impactsense_parser/

graph.rs

use std::collections::{HashMap, HashSet};
use std::fmt;
use std::path::{Path, PathBuf};
use std::sync::Arc;

use futures::stream::{FuturesUnordered, StreamExt};
use neo4rs::{query, Graph};
use thiserror::Error;
use tokio::sync::Mutex;
use tree_sitter::{Node, Tree};

use crate::compress::{compress_full_source, compress_snippet, CompressorClient};
use crate::go_resolve::{
    discover_go_modules, discover_go_replaces, is_likely_third_party_go_import,
    resolve_go_import_to_known_go_file, GoModule, GoReplace,
};
use crate::python_common_external::is_python_common_external_top_level;
use crate::go_stdlib::is_go_stdlib_import;
use crate::ir::{
    api_endpoint_key, external_api_key, module_key, ClassIr, EdgeIr,
    EdgeKind, FunctionIr, ProjectIr, PropertyIr,
};
use crate::python_stdlib::is_python_stdlib_top_level;
use crate::schema::props;
use crate::scanner::ParsedFile;
use crate::LanguageId;

/// Configuration required to connect to a Neo4j database.
#[derive(Debug, Clone)]
pub struct Neo4jConfig {
    /// Bolt URI, e.g. "127.0.0.1:7687" or "neo4j://localhost:7687"
    pub uri: String,
    /// Username, e.g. "neo4j"
    pub user: String,
    /// Password or auth token.
    pub password: String,
}

/// Options for Neo4j persistence diagnostics (import noise, parse-warning caps).
#[derive(Debug, Clone)]
pub struct GraphPersistenceOptions {
    /// Log every unresolved import, including stdlib and third-party.
    pub verbose_imports: bool,
    /// Max Tree-sitter ERROR warnings printed per file; `0` means unlimited.
    pub max_parse_warnings_per_file: usize,
    /// RedCompressor HTTP API settings for `code_bytes` on symbol nodes.
    pub compressor: CompressorConfig,
}

impl Default for GraphPersistenceOptions {
    fn default() -> Self {
        Self {
            verbose_imports: false,
            max_parse_warnings_per_file: 50,
            compressor: CompressorConfig::default(),
        }
    }
}

pub use crate::compress::{CompressorConfig, DEFAULT_COMPRESSOR_URL};

/// Node kinds in the core, reusable graph model.
///
/// We start with File nodes and can extend to Class / Function without
/// breaking the existing schema.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum NodeKind {
    File,
    Class,
    Function,
}

impl fmt::Display for NodeKind {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            NodeKind::File => f.write_str("File"),
            NodeKind::Class => f.write_str("Class"),
            NodeKind::Function => f.write_str("Function"),
        }
    }
}

/// Simple in-memory representation of a discovered class symbol.
#[derive(Debug, Clone)]
struct ClassSymbol {
    /// Simple name, e.g. `BusOperatorCancellationResult`.
    name: String,
    /// Fully-qualified name, e.g. `com.redbus.genai.model.BusOperatorCancellationResult`.
    fqn: String,
    /// For C#: `Some("class" | "interface" | "struct" | "enum" | "record")` on `(:Class { kind })`.
    /// Java/Go leave `None` (unchanged Neo4j Class merge).
    kind: Option<&'static str>,
}

/// C# property for `(:Property)` + `DECLARES_PROPERTY` (CRM-3587).
#[derive(Debug, Clone)]
struct PropertySymbol {
    class_fqn: String,
    name: String,
    /// Stable key: `{class_fqn}.{name}`.
    fqn: String,
    declared_type: Option<String>,
}

/// Simple in-memory representation of a discovered function/method symbol.
#[derive(Debug, Clone)]
struct FunctionSymbol {
    /// Simple name, e.g. `isCapiCancellationSuccess`.
    name: String,
    /// Fully-qualified name, e.g.
    /// `com.redbus.genai.model.BusOperatorCancellationResult.isCapiCancellationSuccess`
    /// or just `top_level_function` for non-class code.
    fqn: String,
    /// FQN of the declaring class, if any.
    class_fqn: Option<String>,
    /// Return type, if extractable.
    return_type: Option<String>,
    /// Parameter types, if extractable.
    param_types: Vec<String>,
    /// Number of parameters.
    param_count: usize,
    /// Declaration modifiers in source order (e.g. `public`, `static`, `async`).
    modifiers: Vec<String>,
    /// Go: `true` if the method has a pointer receiver (`*T`); `None` for non-Go or top-level funcs.
    is_pointer_receiver: Option<bool>,
}

/// In-memory contract representation for behaviour callbacks.
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
struct CallbackContract {
    behaviour: String,
    name: String,
    arity: u32,
    optional: bool,
}

#[derive(Debug, Default, Clone)]
struct ErlangModuleSnapshot {
    implemented_signatures: HashSet<(String, u32)>,
    callback_signatures: HashSet<(String, u32)>,
}

/// Aggregated Erlang behaviour/callback metadata extracted from the AST.
#[derive(Debug, Default)]
struct ErlangBehaviourMetadata {
    behaviour_usages: HashSet<String>,
    declared_callbacks: Vec<(String, u32)>,
    optional_callbacks: HashSet<(String, u32)>,
    behaviour_extensions: HashSet<String>,
    overridden_callbacks: HashSet<(String, u32)>,
}

/// Errors returned by the Neo4j graph integration layer.
#[derive(Debug, Error)]
pub enum GraphError {
    #[error("neo4j connection error: {0}")]
    Connection(#[from] neo4rs::Error),
}

/// Threshold for flushing accumulated relationships to Neo4j.
/// When any relationship batch exceeds this size, all batches are flushed.
const BATCH_FLUSH_THRESHOLD: usize = 3000;

/// Threshold for batched C# node MERGE UNWIND writes per flush (CRM-3592).
const CSHARP_NODE_BATCH_FLUSH_THRESHOLD: usize = 500;

/// Accumulator for batching relationship writes across multiple files.
/// This reduces Neo4j round-trips by accumulating edges and flushing
/// in chunks.
#[derive(Debug, Default)]
struct BatchAccumulator {
    /// (caller_fqn, callee_fqn) pairs for CALLS_FUNCTION
    calls_function: HashSet<(String, String)>,
    /// (fn_fqn, class_fqn) pairs for USES_CLASS
    uses_class: HashSet<(String, String)>,
    /// (derived_class_fqn, base_class_fqn) for Class→Class inheritance (CRM-3584).
    class_uses_class: HashSet<(String, String)>,
    /// (fn_fqn, base_url, norm_path) tuples for CALLS_EXTERNAL_API
    calls_external_api: HashSet<(String, String, String)>,
}

type SharedBatchAccumulator = Arc<Mutex<BatchAccumulator>>;

impl BatchAccumulator {
    fn new() -> Self {
        Self::default()
    }

    /// Add a CALLS_FUNCTION relationship to the batch
    fn add_calls_function(&mut self, caller_fqn: String, callee_fqn: String) {
        self.calls_function.insert((caller_fqn, callee_fqn));
    }

    /// Add a USES_CLASS relationship to the batch
    fn add_uses_class(&mut self, fn_fqn: String, class_fqn: String) {
        self.uses_class.insert((fn_fqn, class_fqn));
    }

    /// Class → Class (`USES_CLASS`, `RelType::ClassUsesClass`) for inheritance (CRM-3584).
    fn add_class_uses_class(&mut self, derived_fqn: String, base_fqn: String) {
        self.class_uses_class.insert((derived_fqn, base_fqn));
    }

    /// Add a CALLS_EXTERNAL_API relationship to the batch
    fn add_calls_external_api(&mut self, fn_fqn: String, base_url: String, norm_path: String) {
        self.calls_external_api.insert((fn_fqn, base_url, norm_path));
    }

    /// Check if any batch has reached the flush threshold
    fn should_flush(&self) -> bool {
        self.calls_function.len() >= BATCH_FLUSH_THRESHOLD
            || self.uses_class.len() >= BATCH_FLUSH_THRESHOLD
            || self.class_uses_class.len() >= BATCH_FLUSH_THRESHOLD
            || self.calls_external_api.len() >= BATCH_FLUSH_THRESHOLD
    }

    /// Total number of accumulated relationships
    fn total_size(&self) -> usize {
        self.calls_function.len()
            + self.uses_class.len()
            + self.class_uses_class.len()
            + self.calls_external_api.len()
    }

    /// Flush all accumulated relationships to Neo4j
    async fn flush(&mut self, graph: &Graph) -> Result<(), GraphError> {
        let total = self.total_size();
        if total == 0 {
            return Ok(());
        }

        println!("Neo4j: flushing {} accumulated relationships...", total);

        // Flush CALLS_FUNCTION
        if !self.calls_function.is_empty() {
            let caller_fqns: Vec<String> = self.calls_function.iter().map(|(c, _)| c.clone()).collect();
            let callee_fqns: Vec<String> = self.calls_function.iter().map(|(_, c)| c.clone()).collect();

            let batch_query = query(
                "
                UNWIND range(0, size($caller_fqns) - 1) AS i
                WITH $caller_fqns[i] AS caller_fqn, $callee_fqns[i] AS callee_fqn
                MERGE (caller:Function { fqn: caller_fqn })
                MERGE (callee:Function { fqn: callee_fqn })
                MERGE (caller)-[:CALLS_FUNCTION]->(callee)
                ",
            )
            .param("caller_fqns", caller_fqns)
            .param("callee_fqns", callee_fqns);

            graph.run(batch_query).await?;
            self.calls_function.clear();
        }

        // Flush USES_CLASS
        if !self.uses_class.is_empty() {
            let fn_fqns: Vec<String> = self.uses_class.iter().map(|(f, _)| f.clone()).collect();
            let cls_fqns: Vec<String> = self.uses_class.iter().map(|(_, c)| c.clone()).collect();

            let batch_query = query(
                "
                UNWIND range(0, size($fn_fqns) - 1) AS i
                WITH $fn_fqns[i] AS fn_fqn, $cls_fqns[i] AS cls_fqn
                MERGE (fn:Function { fqn: fn_fqn })
                MERGE (cls:Class { fqn: cls_fqn })
                MERGE (fn)-[:USES_CLASS]->(cls)
                ",
            )
            .param("fn_fqns", fn_fqns)
            .param("cls_fqns", cls_fqns);

            graph.run(batch_query).await?;
            self.uses_class.clear();
        }

        // Flush Class → Class USES_CLASS (inheritance / interfaces)
        if !self.class_uses_class.is_empty() {
            let derived: Vec<String> = self.class_uses_class.iter().map(|(d, _)| d.clone()).collect();
            let bases: Vec<String> = self.class_uses_class.iter().map(|(_, b)| b.clone()).collect();

            let batch_query = query(
                "
                UNWIND range(0, size($derived_fqns) - 1) AS i
                WITH $derived_fqns[i] AS derived_fqn, $base_fqns[i] AS base_fqn
                MERGE (d:Class { fqn: derived_fqn })
                MERGE (b:Class { fqn: base_fqn })
                MERGE (d)-[:USES_CLASS]->(b)
                ",
            )
            .param("derived_fqns", derived)
            .param("base_fqns", bases);

            graph.run(batch_query).await?;
            self.class_uses_class.clear();
        }

        // Flush CALLS_EXTERNAL_API
        if !self.calls_external_api.is_empty() {
            let fn_fqns: Vec<String> = self.calls_external_api.iter().map(|(f, _, _)| f.clone()).collect();
            let base_urls: Vec<String> = self.calls_external_api.iter().map(|(_, b, _)| b.clone()).collect();
            let norm_paths: Vec<String> = self.calls_external_api.iter().map(|(_, _, n)| n.clone()).collect();

            let batch_query = query(
                "
                UNWIND range(0, size($fn_fqns) - 1) AS i
                WITH $fn_fqns[i] AS fn_fqn, $base_urls[i] AS base_url, $norm_paths[i] AS norm_path
                MERGE (fn:Function { fqn: fn_fqn })
                MERGE (ext:ExternalApi { base_url: base_url, norm_path: norm_path })
                MERGE (fn)-[:CALLS_EXTERNAL_API]->(ext)
                ",
            )
            .param("fn_fqns", fn_fqns)
            .param("base_urls", base_urls)
            .param("norm_paths", norm_paths);

            graph.run(batch_query).await?;
            self.calls_external_api.clear();
        }

        Ok(())
    }
}

async fn flush_shared_accumulator_if_needed(
    shared_accumulator: &SharedBatchAccumulator,
    graph: &Graph,
) -> Result<(), GraphError> {
    let mut local_batch = BatchAccumulator::new();
    {
        let mut guard = shared_accumulator.lock().await;
        if !guard.should_flush() {
            return Ok(());
        }
        std::mem::swap(&mut *guard, &mut local_batch);
    }
    local_batch.flush(graph).await
}

async fn flush_shared_accumulator_force(
    shared_accumulator: &SharedBatchAccumulator,
    graph: &Graph,
) -> Result<(), GraphError> {
    let mut local_batch = BatchAccumulator::new();
    {
        let mut guard = shared_accumulator.lock().await;
        if guard.total_size() == 0 {
            return Ok(());
        }
        std::mem::swap(&mut *guard, &mut local_batch);
    }
    local_batch.flush(graph).await
}

/// Maximum number of Erlang files to write to Neo4j in parallel. This keeps
/// overall throughput high while avoiding excessive concurrent write load on
/// the Neo4j instance.
const MAX_CONCURRENT_ERLANG_WRITES: usize = 8;

/// Path of `file_path` relative to the scan `root` (e.g. `proj1/src/a.go` when root is the parent of `proj1`).
/// Uses canonical root/file when possible so `.` and symlinks line up; falls back to non-canonical prefix rules.
fn repo_relative_file_path(root: &Path, file_path: &Path) -> PathBuf {
    let combined = if file_path.is_absolute() {
        file_path.to_path_buf()
    } else {
        root.join(file_path)
    };
    let root_abs = root.canonicalize().unwrap_or_else(|_| root.to_path_buf());
    let file_abs = combined
        .canonicalize()
        .unwrap_or_else(|_| combined.clone());
    if let Ok(rel) = file_abs.strip_prefix(&root_abs) {
        if !rel.as_os_str().is_empty() {
            return rel.to_path_buf();
        }
    }
    if let Ok(rel) = combined.strip_prefix(root) {
        return rel.to_path_buf();
    }
    if let Ok(rel) = file_path.strip_prefix(root) {
        return rel.to_path_buf();
    }
    if let Ok(rel) = file_path.strip_prefix(&root_abs) {
        return rel.to_path_buf();
    }
    file_path.to_path_buf()
}

/// Repo-relative path string for Neo4j `File.path`, `known_paths`, and incremental cleanup (forward slashes).
fn neo4j_path_string(root: &Path, file_path: &Path) -> String {
    path_str_slash(&repo_relative_file_path(root, file_path))
}

fn path_str_slash(p: &Path) -> String {
    p.to_string_lossy().replace('\\', "/")
}

/// Derive project/service name: first normal path component under the scan root (`proj1` in `proj1/src/...`).
pub(crate) fn derive_project_name(file_path: &Path, root: &Path) -> Option<String> {
    use std::path::Component;
    let rel = repo_relative_file_path(root, file_path);
    for c in rel.components() {
        if let Component::Normal(s) = c {
            return s.to_str().map(|x| x.to_string());
        }
    }
    None
}

fn build_erlang_module_index(files: &[ParsedFile]) -> HashMap<String, ErlangModuleSnapshot> {
    let mut index: HashMap<String, ErlangModuleSnapshot> = HashMap::new();

    for file in files {
        if file.language != LanguageId::Erlang {
            continue;
        }

        let Some(module_name) = resolve_erlang_module_name(&file.path, &file.tree, &file.source) else {
            continue;
        };

        let functions = extract_erlang_functions(&module_name, &file.tree, &file.source);
        let meta = extract_erlang_behaviour_metadata_from_tree(&file.tree, &file.source);
        let contracts = collect_callback_contracts_for_module(
            Some(module_name.as_str()),
            &meta.behaviour_usages,
            &meta.declared_callbacks,
            &meta.optional_callbacks,
        );

        let snapshot = index.entry(module_name).or_default();
        for (name, arity, _fqn) in functions {
            snapshot.implemented_signatures.insert((name, arity));
        }
        for contract in contracts {
            snapshot
                .callback_signatures
                .insert((contract.name, contract.arity));
        }
    }

    index
}

/// Append C# `Class` / `Property` nodes and `DECLARES_CLASS` / `DECLARES_PROPERTY` edges to
/// streaming [`ProjectIr`] (CRM-3595). Keys: File by `path`, Class/Property by `fqn`.
pub fn append_csharp_structural_ir(
    ir: &mut ProjectIr,
    file_path: &str,
    project_name: Option<String>,
    tree: &Tree,
    source: &str,
) {
    let (classes, _, properties) = extract_csharp_symbols(tree, source);
    let language = LanguageId::CSharp.to_string();
    for c in classes {
        ir.classes.push(ClassIr {
            fqn: c.fqn.clone(),
            name: c.name,
            path: file_path.to_string(),
            language: language.clone(),
            project_name: project_name.clone(),
            kind: c.kind.map(str::to_string),
            code_bytes: None,
        });
        ir.edges.push(EdgeIr {
            kind: EdgeKind::DeclaresClass,
            from_label: String::from("File"),
            from_key: file_path.to_string(),
            to_label: String::from("Class"),
            to_key: c.fqn,
        });
    }
    for p in properties {
        ir.properties.push(PropertyIr {
            fqn: p.fqn.clone(),
            name: p.name,
            class_fqn: p.class_fqn.clone(),
            path: file_path.to_string(),
            language: language.clone(),
            project_name: project_name.clone(),
            declared_type: p.declared_type,
            code_bytes: None,
        });
        ir.edges.push(EdgeIr {
            kind: EdgeKind::DeclaresProperty,
            from_label: String::from("Class"),
            from_key: p.class_fqn,
            to_label: String::from("Property"),
            to_key: p.fqn,
        });
    }
}

/// Append Java `Class` nodes and `DECLARES_CLASS` edges (no `Property` in this pipeline).
pub fn append_java_class_ir(
    ir: &mut ProjectIr,
    file_path: &str,
    project_name: Option<String>,
    tree: &Tree,
    source: &str,
) {
    let package = extract_java_package(source);
    let (classes, _) = extract_java_symbols(tree, source, package.as_deref());
    let language = LanguageId::Java.to_string();
    for c in classes {
        ir.classes.push(ClassIr {
            fqn: c.fqn.clone(),
            name: c.name,
            path: file_path.to_string(),
            language: language.clone(),
            project_name: project_name.clone(),
            kind: c.kind.map(str::to_string),
            code_bytes: None,
        });
        ir.edges.push(EdgeIr {
            kind: EdgeKind::DeclaresClass,
            from_label: String::from("File"),
            from_key: file_path.to_string(),
            to_label: String::from("Class"),
            to_key: c.fqn,
        });
    }
}

/// Cleanup stale graph scope for incremental updates.
///
/// The caller passes `cleanup_targets` from delta resolution (deleted files,
/// rename old paths, and modified files). This function normalizes each target
/// path relative to `root`, then deletes file-scoped entities by path:
/// - `(:File {path})`
/// - `(:Module {path})`
/// - `(:Class {path})`
/// - `(:Function {path})`
///
/// This is intended to run before incremental upsert so stale symbols and
/// relationships tied to previous file contents are removed.
pub async fn cleanup_incremental_targets_in_neo4j(
    cfg: &Neo4jConfig,
    root: &Path,
    cleanup_targets: &[String],
) -> Result<(), GraphError> {
    if cleanup_targets.is_empty() {
        println!("Neo4j cleanup: no cleanup targets, skipping.");
        return Ok(());
    }

    let normalized_paths: Vec<String> = cleanup_targets
        .iter()
        .map(|target| neo4j_path_string(root, Path::new(target)))
        .collect::<HashSet<_>>()
        .into_iter()
        .collect();

    if normalized_paths.is_empty() {
        println!("Neo4j cleanup: no normalized paths, skipping.");
        return Ok(());
    }

    println!(
        "Neo4j cleanup: deleting stale graph scope for {} path(s)...",
        normalized_paths.len()
    );

    let graph = Graph::new(&cfg.uri, &cfg.user, &cfg.password).await?;

    let delete_files = query(
        "
        UNWIND $paths AS path
        OPTIONAL MATCH (f:File { path: path })
        DETACH DELETE f
        ",
    )
    .param("paths", normalized_paths.clone());
    graph.run(delete_files).await?;

    let delete_modules = query(
        "
        UNWIND $paths AS path
        OPTIONAL MATCH (m:Module { path: path })
        DETACH DELETE m
        ",
    )
    .param("paths", normalized_paths.clone());
    graph.run(delete_modules).await?;

    let delete_classes = query(
        "
        UNWIND $paths AS path
        OPTIONAL MATCH (c:Class { path: path })
        DETACH DELETE c
        ",
    )
    .param("paths", normalized_paths.clone());
    graph.run(delete_classes).await?;

    let delete_functions = query(
        "
        UNWIND $paths AS path
        OPTIONAL MATCH (fn:Function { path: path })
        DETACH DELETE fn
        ",
    )
    .param("paths", normalized_paths);
    graph.run(delete_functions).await?;

    println!("Neo4j cleanup: stale graph scope deleted.");
    Ok(())
}

/// Push a graph representation of the parsed files into Neo4j.
///
/// Current behavior:
/// - For each ParsedFile, creates/merges a `(:File { path, language })` node.
/// - For Java sources:
///   - Extracts package, classes, and methods from the Tree-Sitter AST and creates
///     `(:Class)` and `(:Function)` nodes.
///   - Links them via `(:File)-[:DECLARES_CLASS]->(:Class)` and
///     `(:Class)-[:DECLARES_FUNCTION]->(:Function)`.
///   - For methods and top-level functions, also links
///     `(:File)-[:DECLARES_FUNCTION]->(:Function)`.
///   - Extracts `import com.redbus.genai.*` statements and creates
///     `(:File)-[:DEPENDS_ON_FILE]->(:File)` edges when the target file is known.
/// - For C# sources:
///   - Extracts `using` namespaces from the AST and creates
///     `(:File)-[:DEPENDS_ON_FILE]->(:File)` edges to other parsed `.cs` files in the
///     same namespace (excluding `System.*` / `Microsoft.*`).
///   - Resolves `USES_CLASS` type names using usings and a batch index of types.
///   - Class/method FQNs include nested types (`Ns.Outer.Inner`); enums are `(:Class { kind })`.
///   - `Function` nodes store return type, parameter types/count, and modifiers when present.
///   - Builds `CALLS_FUNCTION` from invocations in methods, constructors, and property
///     accessors, resolving member callees via field/local types and a small BCL map.
/// - For non-Java languages:
///   - Best-effort extraction of top-level functions and creation of
///     `(:Function)` nodes plus `(:File)-[:DECLARES_FUNCTION]->(:Function)` edges.
///
/// This unified schema supports file-level, class-level, and function-level
/// structure while remaining compatible with existing data.
fn should_emit_parse_warnings_for_path(file_path: &str) -> bool {
    let p = file_path.replace('\\', "/").to_lowercase();
    if p.contains("/vendordocs/") {
        return false;
    }
    if p.contains("/refund_issue/") {
        return false;
    }
    true
}

fn emit_limited_parse_warnings(
    label: &str,
    file_path: &str,
    warnings: Vec<(usize, usize, String)>,
    max_per_file: usize,
) {
    if !should_emit_parse_warnings_for_path(file_path) {
        return;
    }
    let total = warnings.len();
    if max_per_file == 0 {
        for (line, col, snippet) in warnings {
            println!(
                "{label} parse warning {file_path}:{line}:{col} - {snippet}",
            );
        }
        return;
    }
    for (i, (line, col, snippet)) in warnings.into_iter().enumerate() {
        if i >= max_per_file {
            let rest = total.saturating_sub(i);
            if rest > 0 {
                println!(
                    "{label} parse warning {file_path}: ... {rest} more suppressed (set max_parse_warnings_per_file to 0 for unlimited)",
                );
            }
            break;
        }
        println!(
            "{label} parse warning {file_path}:{line}:{col} - {snippet}",
        );
    }
}

fn should_log_unresolved_import(
    verbose_imports: bool,
    is_stdlib: bool,
    is_third_party: bool,
) -> bool {
    verbose_imports || (!is_stdlib && !is_third_party)
}

pub async fn persist_files_to_neo4j(
    cfg: &Neo4jConfig,
    root: &Path,
    files: &[ParsedFile],
    clean: bool,
    follow_symlinks: bool,
    persistence: &GraphPersistenceOptions,
) -> Result<(), GraphError> {
    // Establish connection to Neo4j using the provided configuration.
    let graph = Graph::new(&cfg.uri, &cfg.user, &cfg.password).await?;

    // If --clean flag is set, delete all existing nodes and relationships first.
    if clean {
        println!("Neo4j: deleting all existing nodes and relationships...");
        let delete_query = query("MATCH (n) DETACH DELETE n");
        graph.run(delete_query).await?;
        println!("Neo4j: database cleaned, starting fresh graph construction");
    }

    // Pre-compute the set of file paths we know about so that we never create
    // "phantom" File nodes for imports that do not correspond to a parsed file.
    let mut known_paths: HashSet<String> = HashSet::new();
    for file in files {
        known_paths.insert(neo4j_path_string(root, &file.path));
    }

    let go_modules = discover_go_modules(root, follow_symlinks).unwrap_or_else(|e| {
        eprintln!("Neo4j: warning: could not discover go.mod modules: {e}");
        Vec::new()
    });

    let go_replaces = discover_go_replaces(root, follow_symlinks).unwrap_or_else(|e| {
        eprintln!("Neo4j: warning: could not discover go.mod replace directives: {e}");
        Vec::new()
    });

    let csharp_batch_index = build_csharp_batch_index(files, root);

    let compressor_client = if persistence.compressor.enabled {
        match CompressorClient::from_config(&persistence.compressor) {
            Ok(client) => {
                if let Err(e) = client.health_check().await {
                    eprintln!("RedCompressor: health check failed ({e}); compression may be unavailable");
                }
                Some(client)
            }
            Err(e) => {
                eprintln!("RedCompressor: failed to create client ({e}); skipping code_bytes");
                None
            }
        }
    } else {
        None
    };
    let compressor = compressor_client.as_ref();

    // Global batch accumulator for relationships
    let mut accumulator = BatchAccumulator::new();
    let erlang_module_index = build_erlang_module_index(files);

    let total_files = files.len();
    let mut erlang_futures: FuturesUnordered<_> = FuturesUnordered::new();
    let erlang_accumulator: SharedBatchAccumulator =
        Arc::new(Mutex::new(BatchAccumulator::new()));

    for (idx, file) in files.iter().enumerate() {
        let language = file.language.to_string();
        let path = neo4j_path_string(root, &file.path);
        let project_name = derive_project_name(&file.path, root);

        // Simple CLI progress indication: how many files have been processed.
        println!(
            "Neo4j: processing file {}/{} ({})",
            idx + 1,
            total_files,
            path
        );

        // MERGE ensures idempotent creation: existing nodes are matched by path.
        let q = query(
            "
            MERGE (f:File { path: $path })
            ON CREATE SET f.language = $language,
                          f.project_name = $project_name,
                          f.is_test = $is_test
            ON MATCH SET  f.language = $language,
                          f.project_name = $project_name,
                          f.is_test = $is_test
            ",
        )
        .param("path", path.clone())
        .param("language", language.clone())
        .param("project_name", project_name.clone())
        .param("is_test", file.is_test);

        graph.run(q).await?;

        // Language-specific symbol and dependency extraction.
        let source = &file.source;
        match file.language {
            LanguageId::Java => {
                persist_java_structure(
                    &graph,
                    &path,
                    file,
                    source,
                    &known_paths,
                    project_name.clone(),
                    &mut accumulator,
                    persistence,
                    compressor,
                )
                .await?;
            }
            LanguageId::CSharp => {
                persist_csharp_structure(
                    &graph,
                    &path,
                    file,
                    source,
                    project_name.clone(),
                    &known_paths,
                    &csharp_batch_index,
                    &mut accumulator,
                    compressor,
                )
                .await?;
            }
            LanguageId::Erlang => {
                // Queue Erlang writes so we can run several modules in
                // parallel, but cap the number of in-flight tasks to avoid
                // overloading Neo4j.
                erlang_futures.push(persist_erlang_structure(
                    &graph,
                    file,
                    path.clone(),
                    source,
                    project_name.clone(),
                    &erlang_module_index,
                    erlang_accumulator.clone(),
                    compressor,
                ));

                if erlang_futures.len() >= MAX_CONCURRENT_ERLANG_WRITES {
                    if let Some(res) = erlang_futures.next().await {
                        res?;
                    }
                    flush_shared_accumulator_if_needed(&erlang_accumulator, &graph).await?;
                }
            }
            LanguageId::Go => {
                persist_go_structure(
                    &graph,
                    &path,
                    file,
                    source,
                    &known_paths,
                    project_name.clone(),
                    &mut accumulator,
                    root,
                    &go_modules,
                    &go_replaces,
                    persistence,
                    compressor,
                )
                .await?;
            }
            _ => {
                // For non-Java languages (e.g., JS, TS, Python, Rust),
                // we make a best-effort attempt to create top-level function
                // symbols linked to their files so mixed queries (file +
                // function) still work for non-class codebases.
                persist_non_java_functions(
                    &graph,
                    &path,
                    file,
                    source,
                    project_name.clone(),
                    &known_paths,
                    &mut accumulator,
                    persistence,
                    compressor,
                )
                .await?;
            }
        }

        // Check if we should flush accumulated relationships
        if accumulator.should_flush() {
            accumulator.flush(&graph).await?;
        }
        flush_shared_accumulator_if_needed(&erlang_accumulator, &graph).await?;
    }

    // Drain any remaining Erlang writes.
    while let Some(res) = erlang_futures.next().await {
        res?;
        flush_shared_accumulator_if_needed(&erlang_accumulator, &graph).await?;
    }

    // Final flush of any remaining accumulated relationships
    accumulator.flush(&graph).await?;
    flush_shared_accumulator_force(&erlang_accumulator, &graph).await?;

    // Establish SAME_API relationships between ApiEndpoint and ExternalApi
    // based on normalized path. This runs once per push and is idempotent
    // thanks to MERGE on the relationship.
    let same_api_query = query(
        "
        MATCH (ep:ApiEndpoint)
        MATCH (ext:ExternalApi)
        WHERE ep.norm_path IS NOT NULL
          AND ext.norm_path IS NOT NULL
          AND ep.norm_path = ext.norm_path
        MERGE (ep)-[:SAME_API]->(ext)
        ",
    );

    graph.run(same_api_query).await?;

    println!("Neo4j: finished processing {} files.", total_files);

    Ok(())
}

/// Handle Java-specific structure:
/// - Package / class / method symbols.
/// - File-level dependency edges via imports.
async fn persist_java_structure(
    graph: &Graph,
    file_path: &str,
    file: &ParsedFile,
    source: &str,
    known_paths: &HashSet<String>,
    project_name: Option<String>,
    accumulator: &mut BatchAccumulator,
    persistence: &GraphPersistenceOptions,
    compressor: Option<&CompressorClient>,
) -> Result<(), GraphError> {
    let package = extract_java_package(source);
    let (classes, methods) = extract_java_symbols(&file.tree, source, package.as_deref());
    let class_spans = extract_java_class_spans(&file.tree, source, package.as_deref());
    let method_spans = extract_java_method_body_spans(&file.tree, source, package.as_deref());

    emit_limited_parse_warnings(
        "Java",
        file_path,
        extract_java_parse_warnings(&file.tree, source),
        persistence.max_parse_warnings_per_file,
    );

    let class_ann_map: HashMap<String, Vec<String>> =
        extract_java_class_annotations(&file.tree, source, package.as_deref())
            .into_iter()
            .collect();
    let method_ann_map: HashMap<String, Vec<String>> =
        extract_java_method_annotations(&file.tree, source, package.as_deref())
            .into_iter()
            .collect();

    // First create/merge Class nodes and link them to the File.
    for class in &classes {
        let annotations = class_ann_map
            .get(&class.fqn)
            .cloned()
            .unwrap_or_default();
        let code_bytes = code_bytes_for_span(
            compressor,
            source,
            class_spans.get(&class.fqn).copied(),
            LanguageId::Java,
        )
        .await;
        let q = query(
            "
            MATCH (f:File { path: $path })
            MERGE (c:Class { fqn: $class_fqn })
            ON CREATE SET c.name = $class_name,
                          c.path = $path,
                          c.project_name = $project_name,
                          c.annotations = $annotations,
                          c.code_bytes = $code_bytes
            ON MATCH SET  c.name = $class_name,
                          c.path = $path,
                          c.project_name = $project_name,
                          c.annotations = $annotations,
                          c.code_bytes = coalesce($code_bytes, c.code_bytes)
            MERGE (f)-[:DECLARES_CLASS]->(c)
            ",
        )
        .param("path", file_path.to_string())
        .param("class_fqn", class.fqn.clone())
        .param("class_name", class.name.clone())
        .param("project_name", project_name.clone())
        .param("annotations", annotations)
        .param(props::CODE_BYTES, code_bytes);

        graph.run(q).await?;
    }

    // Then create/merge Function nodes and link them to File and Class (if any).
    for func in &methods {
        let fn_annotations = method_ann_map
            .get(&func.fqn)
            .cloned()
            .unwrap_or_default();
        let code_bytes = code_bytes_for_span(
            compressor,
            source,
            method_spans.get(&func.fqn).copied(),
            LanguageId::Java,
        )
        .await;
        match &func.class_fqn {
            Some(class_fqn) => {
                let q = query(
                    "
                    MATCH (f:File { path: $path })
                    MERGE (cls:Class { fqn: $class_fqn })
                    MERGE (fn:Function { fqn: $fn_fqn })
                    ON CREATE SET fn.name = $fn_name,
                                  fn.path = $path,
                                  fn.project_name = $project_name,
                                  fn.return_type = $return_type,
                                  fn.param_types = $param_types,
                                  fn.param_count = $param_count,
                                  fn.annotations = $fn_annotations,
                                  fn.code_bytes = $code_bytes
                    ON MATCH SET  fn.name = $fn_name,
                                  fn.path = $path,
                                  fn.project_name = $project_name,
                                  fn.return_type = coalesce($return_type, fn.return_type),
                                  fn.param_types = coalesce($param_types, fn.param_types),
                                  fn.param_count = coalesce($param_count, fn.param_count),
                                  fn.annotations = $fn_annotations,
                                  fn.code_bytes = coalesce($code_bytes, fn.code_bytes)
                    MERGE (f)-[:DECLARES_FUNCTION]->(fn)
                    MERGE (cls)-[:DECLARES_FUNCTION]->(fn)
                    ",
                )
                .param("path", file_path.to_string())
                .param("class_fqn", class_fqn.clone())
                .param("fn_fqn", func.fqn.clone())
                .param("fn_name", func.name.clone())
                .param("project_name", project_name.clone())
                .param("return_type", func.return_type.clone())
                .param("param_types", func.param_types.clone())
                .param("param_count", func.param_count as i64)
                .param("fn_annotations", fn_annotations)
                .param(props::CODE_BYTES, code_bytes.clone());

                graph.run(q).await?;
            }
            None => {
                let q = query(
                    "
                    MATCH (f:File { path: $path })
                    MERGE (fn:Function { fqn: $fn_fqn })
                    ON CREATE SET fn.name = $fn_name,
                                  fn.path = $path,
                                  fn.project_name = $project_name,
                                  fn.return_type = $return_type,
                                  fn.param_types = $param_types,
                                  fn.param_count = $param_count,
                                  fn.annotations = $fn_annotations,
                                  fn.code_bytes = $code_bytes
                    ON MATCH SET  fn.name = $fn_name,
                                  fn.path = $path,
                                  fn.project_name = $project_name,
                                  fn.return_type = coalesce($return_type, fn.return_type),
                                  fn.param_types = coalesce($param_types, fn.param_types),
                                  fn.param_count = coalesce($param_count, fn.param_count),
                                  fn.annotations = $fn_annotations,
                                  fn.code_bytes = coalesce($code_bytes, fn.code_bytes)
                    MERGE (f)-[:DECLARES_FUNCTION]->(fn)
                    ",
                )
                .param("path", file_path.to_string())
                .param("fn_fqn", func.fqn.clone())
                .param("fn_name", func.name.clone())
                .param("project_name", project_name.clone())
                .param("return_type", func.return_type.clone())
                .param("param_types", func.param_types.clone())
                .param("param_count", func.param_count as i64)
                .param("fn_annotations", fn_annotations)
                .param(props::CODE_BYTES, code_bytes);

                graph.run(q).await?;
            }
        }
    }

    for (derived, base) in extract_java_inheritance_edges(&file.tree, source, package.as_deref()) {
        accumulator.add_class_uses_class(derived, base);
    }
    for (cls, dep) in extract_java_injected_dependencies(&file.tree, source, package.as_deref()) {
        accumulator.add_class_uses_class(cls, dep);
    }

    // Build a basic intra-class call graph between methods. (BATCHED)
    //
    // For now, we conservatively resolve calls to methods on the same declaring
    // class (or same package if no class is present). This still enables
    // useful "which methods are impacted?" queries without requiring full
    // Java type resolution.
    // Accumulate CALLS_FUNCTION relationships (global batching)
    let calls = extract_java_calls(&file.tree, source, package.as_deref());
    for (caller_fqn, callee_fqn) in calls {
        accumulator.add_calls_function(caller_fqn, callee_fqn);
    }

    // Best-effort file-level dependency edges for Java sources.
    //
    // We intentionally keep the logic simple and conservative:
    // - Only consider imports in the `com.redbus.genai.*` namespace.
    // - Only create edges to targets that are also in the scanned file set.
    let internal_imports = extract_internal_java_imports(source);
    for import_fqn in internal_imports {
        if let Some(dep_path) = map_import_to_project_path(file_path, &import_fqn) {
            // Skip imports that do not correspond to a parsed file.
            if !known_paths.contains(&dep_path) {
                continue;
            }

            // Ensure the target File node exists and then create the dependency edge.
            let dep_query = query(
                "
                MERGE (src:File { path: $src_path })
                MERGE (dst:File { path: $dst_path })
                MERGE (src)-[:DEPENDS_ON_FILE]->(dst)
                ",
            )
            .param("src_path", file_path.to_string())
            .param("dst_path", dep_path.clone());

            graph.run(dep_query).await?;
        }
    }

    // Java Spring Framework API endpoint detection.
    //
    // Detect Spring Boot annotations like @GetMapping, @PostMapping, @RequestMapping
    // and create ApiEndpoint nodes with HANDLED_BY edges to the handler methods.
    let endpoints = extract_java_spring_endpoints(source);
    for (http_methods, path_template, handler_name) in endpoints {
        let norm_path = normalize_api_path(&path_template);

        // Create or update the ApiEndpoint node.
        let api_query = query(
            "
            MERGE (api:ApiEndpoint { path: $path })
            ON CREATE SET api.methods      = $methods,
                          api.protocol     = 'http',
                          api.framework    = 'spring',
                          api.project_name = $project_name,
                          api.norm_path    = $norm_path
            ON MATCH  SET api.methods      = $methods,
                          api.protocol     = coalesce(api.protocol, 'http'),
                          api.framework    = coalesce(api.framework, 'spring'),
                          api.project_name = coalesce(api.project_name, $project_name),
                          api.norm_path    = coalesce(api.norm_path, $norm_path)
            ",
        )
        .param("path", path_template.clone())
        .param("methods", http_methods.clone())
        .param("project_name", project_name.clone())
        .param("norm_path", norm_path.clone());

        graph.run(api_query).await?;

        // Link the endpoint to the matching handler method(s) in this file.
        for func in &methods {
            if func.name != handler_name {
                continue;
            }

            let rel_query = query(
                "
                MERGE (fn:Function { fqn: $fn_fqn })
                MERGE (api:ApiEndpoint { path: $path })
                MERGE (api)-[:HANDLED_BY]->(fn)
                ",
            )
            .param("fn_fqn", func.fqn.clone())
            .param("path", path_template.clone());

            graph.run(rel_query).await?;
        }
    }

    // External APIs called from this Java file (HTTP URL detection).
    let external_urls = extract_external_http_urls(source);
    for full_url in external_urls {
        let (protocol_opt, host, path) = split_url_protocol_host_and_path(&full_url);
        let protocol = protocol_opt.unwrap_or_else(|| "http".to_string());
        let base_url = format!("{protocol}://{host}");
        let name = host.clone();
        let norm_path = normalize_api_path(&path);

        // Create ExternalApi node (still needs immediate execution for node creation)
        let ext_query = query(
            "
            MERGE (ext:ExternalApi { base_url: $base_url, norm_path: $norm_path })
            ON CREATE SET ext.name         = $name,
                          ext.path         = $path,
                          ext.protocol     = $protocol,
                          ext.provider     = $provider,
                          ext.project_name = $project_name
            ON MATCH  SET ext.name         = coalesce(ext.name, $name),
                          ext.path         = coalesce(ext.path, $path),
                          ext.protocol     = coalesce(ext.protocol, $protocol),
                          ext.provider     = coalesce(ext.provider, $provider),
                          ext.project_name = coalesce(ext.project_name, $project_name)
            ",
        )
        .param("name", name.clone())
        .param("base_url", base_url.clone())
        .param("path", path.clone())
        .param("norm_path", norm_path.clone())
        .param("protocol", protocol.clone())
        .param("provider", name.clone())
        .param("project_name", project_name.clone());

        graph.run(ext_query).await?;

        // Accumulate CALLS_EXTERNAL_API relationships (global batching)
        for func in &methods {
            accumulator.add_calls_external_api(
                func.fqn.clone(),
                base_url.clone(),
                norm_path.clone(),
            );
        }
    }

    // Accumulate USES_CLASS relationships (global batching)
    let used_classes = extract_java_used_classes(&file.tree, source, package.as_deref());
    for (fn_fqn, class_fqn) in used_classes {
        accumulator.add_uses_class(fn_fqn, class_fqn);
    }

    Ok(())
}

/// Handle C#-specific structure:
/// - Class / method symbols (using Tree-Sitter C#).
/// - External HTTP APIs referenced in the source, linked from methods.
async fn persist_csharp_structure(
    graph: &Graph,
    file_path: &str,
    file: &ParsedFile,
    source: &str,
    project_name: Option<String>,
    known_paths: &HashSet<String>,
    csharp_index: &CSharpBatchIndex,
    accumulator: &mut BatchAccumulator,
    compressor: Option<&CompressorClient>,
) -> Result<(), GraphError> {
    let language = file.language.to_string();
    let namespace = extract_csharp_namespace(&file.tree, source);
    let using_summary = extract_csharp_using_summary(&file.tree, source);

    let (classes, methods, property_symbols) = extract_csharp_symbols(&file.tree, source);
    let class_spans = extract_csharp_class_spans(&file.tree, source);
    let property_spans = extract_csharp_property_spans(&file.tree, source);
    let method_spans = extract_csharp_method_body_spans_map(&file.tree, source, namespace.as_deref());

    // Class nodes: batched MERGE (CRM-3592); `path` only on CREATE for partials (CRM-3591).
    for chunk in classes.chunks(CSHARP_NODE_BATCH_FLUSH_THRESHOLD.max(1)) {
        let class_fqns: Vec<String> = chunk.iter().map(|c| c.fqn.clone()).collect();
        let class_names: Vec<String> = chunk.iter().map(|c| c.name.clone()).collect();
        let class_kinds: Vec<String> = chunk
            .iter()
            .map(|c| c.kind.unwrap_or("class").to_string())
            .collect();
        let mut code_bytes_list: Vec<Option<Vec<u8>>> = Vec::with_capacity(chunk.len());
        for c in chunk {
            code_bytes_list.push(
                code_bytes_for_span(
                    compressor,
                    source,
                    class_spans.get(&c.fqn).copied(),
                    LanguageId::CSharp,
                )
                .await,
            );
        }
        let q = query(
            "
            UNWIND range(0, size($class_fqns) - 1) AS i
            WITH $file_path AS path, $class_fqns[i] AS class_fqn, $class_names[i] AS class_name,
                 $class_kinds[i] AS class_kind, $project_name AS project_name, $language AS language,
                 $code_bytes_list[i] AS code_bytes
            MATCH (f:File { path: path })
            MERGE (c:Class { fqn: class_fqn })
            ON CREATE SET c.name = class_name, c.path = path, c.project_name = project_name,
                          c.language = language, c.kind = class_kind, c.code_bytes = code_bytes
            ON MATCH SET c.name = class_name, c.project_name = project_name, c.language = language,
                         c.kind = class_kind, c.code_bytes = coalesce(code_bytes, c.code_bytes)
            MERGE (f)-[:DECLARES_CLASS]->(c)
            ",
        )
        .param("file_path", file_path.to_string())
        .param("class_fqns", class_fqns)
        .param("class_names", class_names)
        .param("class_kinds", class_kinds)
        .param("project_name", project_name.clone())
        .param("language", language.clone())
        .param("code_bytes_list", code_bytes_list);

        graph.run(q).await?;
    }

    for chunk in property_symbols.chunks(CSHARP_NODE_BATCH_FLUSH_THRESHOLD.max(1)) {
        let class_fqns: Vec<String> = chunk.iter().map(|p| p.class_fqn.clone()).collect();
        let prop_fqns: Vec<String> = chunk.iter().map(|p| p.fqn.clone()).collect();
        let prop_names: Vec<String> = chunk.iter().map(|p| p.name.clone()).collect();
        let decl_types: Vec<Option<String>> = chunk.iter().map(|p| p.declared_type.clone()).collect();
        let mut code_bytes_list: Vec<Option<Vec<u8>>> = Vec::with_capacity(chunk.len());
        for p in chunk {
            code_bytes_list.push(
                code_bytes_for_span(
                    compressor,
                    source,
                    property_spans.get(&p.fqn).copied(),
                    LanguageId::CSharp,
                )
                .await,
            );
        }
        let q = query(
            "
            UNWIND range(0, size($prop_fqns) - 1) AS i
            WITH $class_fqns[i] AS class_fqn, $prop_fqns[i] AS prop_fqn, $prop_names[i] AS prop_name,
                 $decl_types[i] AS declared_type, $file_path AS path,
                 $project_name AS project_name, $language AS language,
                 $code_bytes_list[i] AS code_bytes
            MATCH (c:Class { fqn: class_fqn })
            MERGE (p:Property { fqn: prop_fqn })
            ON CREATE SET p.name = prop_name, p.path = path, p.project_name = project_name,
                          p.language = language, p.declared_type = declared_type, p.code_bytes = code_bytes
            ON MATCH SET p.name = prop_name, p.project_name = project_name, p.language = language,
                         p.declared_type = coalesce(declared_type, p.declared_type),
                         p.code_bytes = coalesce(code_bytes, p.code_bytes)
            MERGE (c)-[:DECLARES_PROPERTY]->(p)
            ",
        )
        .param("class_fqns", class_fqns)
        .param("prop_fqns", prop_fqns)
        .param("prop_names", prop_names)
        .param("decl_types", decl_types)
        .param("file_path", file_path.to_string())
        .param("project_name", project_name.clone())
        .param("language", language.clone())
        .param("code_bytes_list", code_bytes_list);

        graph.run(q).await?;
    }

    let methods_with_class: Vec<&FunctionSymbol> =
        methods.iter().filter(|f| f.class_fqn.is_some()).collect();
    for chunk in methods_with_class.chunks(CSHARP_NODE_BATCH_FLUSH_THRESHOLD.max(1)) {
        let class_fqns: Vec<String> = chunk
            .iter()
            .map(|f| f.class_fqn.clone().unwrap_or_default())
            .collect();
        let fn_fqns: Vec<String> = chunk.iter().map(|f| f.fqn.clone()).collect();
        let fn_names: Vec<String> = chunk.iter().map(|f| f.name.clone()).collect();
        let return_types: Vec<Option<String>> = chunk.iter().map(|f| f.return_type.clone()).collect();
        let param_types_list: Vec<Vec<String>> = chunk.iter().map(|f| f.param_types.clone()).collect();
        let param_counts: Vec<i64> = chunk.iter().map(|f| f.param_count as i64).collect();
        let modifiers_list: Vec<Vec<String>> = chunk.iter().map(|f| f.modifiers.clone()).collect();
        let mut code_bytes_list: Vec<Option<Vec<u8>>> = Vec::with_capacity(chunk.len());
        for f in chunk {
            code_bytes_list.push(
                code_bytes_for_span(
                    compressor,
                    source,
                    method_spans.get(&f.fqn).copied(),
                    LanguageId::CSharp,
                )
                .await,
            );
        }
        let q = query(
            "
            UNWIND range(0, size($fn_fqns) - 1) AS i
            WITH $file_path AS path, $class_fqns[i] AS class_fqn, $fn_fqns[i] AS fn_fqn,
                 $fn_names[i] AS fn_name, $return_types[i] AS return_type,
                 $param_types_list[i] AS param_types, $param_counts[i] AS param_count,
                 $modifiers_list[i] AS modifiers, $project_name AS project_name, $language AS language,
                 $code_bytes_list[i] AS code_bytes
            MATCH (f:File { path: path })
            MERGE (cls:Class { fqn: class_fqn })
            MERGE (fn:Function { fqn: fn_fqn })
            ON CREATE SET fn.name = fn_name, fn.path = path, fn.project_name = project_name,
                          fn.language = language, fn.return_type = return_type,
                          fn.param_types = param_types, fn.param_count = param_count,
                          fn.modifiers = modifiers, fn.code_bytes = code_bytes
            ON MATCH SET fn.name = fn_name, fn.project_name = project_name, fn.language = language,
                         fn.return_type = coalesce(return_type, fn.return_type),
                         fn.param_types = coalesce(param_types, fn.param_types),
                         fn.param_count = coalesce(param_count, fn.param_count),
                         fn.modifiers = coalesce(modifiers, fn.modifiers),
                         fn.code_bytes = coalesce(code_bytes, fn.code_bytes)
            MERGE (f)-[:DECLARES_FUNCTION]->(fn)
            MERGE (cls)-[:DECLARES_FUNCTION]->(fn)
            ",
        )
        .param("file_path", file_path.to_string())
        .param("class_fqns", class_fqns)
        .param("fn_fqns", fn_fqns)
        .param("fn_names", fn_names)
        .param("return_types", return_types)
        .param("param_types_list", param_types_list)
        .param("param_counts", param_counts)
        .param("modifiers_list", modifiers_list)
        .param("project_name", project_name.clone())
        .param("language", language.clone())
        .param("code_bytes_list", code_bytes_list);

        graph.run(q).await?;
    }

    let methods_top: Vec<&FunctionSymbol> = methods.iter().filter(|f| f.class_fqn.is_none()).collect();
    for chunk in methods_top.chunks(CSHARP_NODE_BATCH_FLUSH_THRESHOLD.max(1)) {
        let fn_fqns: Vec<String> = chunk.iter().map(|f| f.fqn.clone()).collect();
        let fn_names: Vec<String> = chunk.iter().map(|f| f.name.clone()).collect();
        let return_types: Vec<Option<String>> = chunk.iter().map(|f| f.return_type.clone()).collect();
        let param_types_list: Vec<Vec<String>> = chunk.iter().map(|f| f.param_types.clone()).collect();
        let param_counts: Vec<i64> = chunk.iter().map(|f| f.param_count as i64).collect();
        let modifiers_list: Vec<Vec<String>> = chunk.iter().map(|f| f.modifiers.clone()).collect();
        let mut code_bytes_list: Vec<Option<Vec<u8>>> = Vec::with_capacity(chunk.len());
        for f in chunk {
            code_bytes_list.push(
                code_bytes_for_span(
                    compressor,
                    source,
                    method_spans.get(&f.fqn).copied(),
                    LanguageId::CSharp,
                )
                .await,
            );
        }
        let q = query(
            "
            UNWIND range(0, size($fn_fqns) - 1) AS i
            WITH $file_path AS path, $fn_fqns[i] AS fn_fqn, $fn_names[i] AS fn_name,
                 $return_types[i] AS return_type, $param_types_list[i] AS param_types,
                 $param_counts[i] AS param_count, $modifiers_list[i] AS modifiers,
                 $project_name AS project_name, $language AS language,
                 $code_bytes_list[i] AS code_bytes
            MATCH (f:File { path: path })
            MERGE (fn:Function { fqn: fn_fqn })
            ON CREATE SET fn.name = fn_name, fn.path = path, fn.project_name = project_name,
                          fn.language = language, fn.return_type = return_type,
                          fn.param_types = param_types, fn.param_count = param_count,
                          fn.modifiers = modifiers, fn.code_bytes = code_bytes
            ON MATCH SET fn.name = fn_name, fn.project_name = project_name, fn.language = language,
                         fn.return_type = coalesce(return_type, fn.return_type),
                         fn.param_types = coalesce(param_types, fn.param_types),
                         fn.param_count = coalesce(param_count, fn.param_count),
                         fn.modifiers = coalesce(modifiers, fn.modifiers),
                         fn.code_bytes = coalesce(code_bytes, fn.code_bytes)
            MERGE (f)-[:DECLARES_FUNCTION]->(fn)
            ",
        )
        .param("file_path", file_path.to_string())
        .param("fn_fqns", fn_fqns)
        .param("fn_names", fn_names)
        .param("return_types", return_types)
        .param("param_types_list", param_types_list)
        .param("param_counts", param_counts)
        .param("modifiers_list", modifiers_list)
        .param("project_name", project_name.clone())
        .param("language", language.clone())
        .param("code_bytes_list", code_bytes_list);

        graph.run(q).await?;
    }

    // Best-effort HTTP API endpoint + external API detection for C#.
    //
    // 1) ApiEndpoint + HANDLED_BY:
    //    - ASP.NET-style attributes ([HttpGet], [Route], etc.) are read from the
    //      Tree-sitter AST (including multi-line attribute spans). Class-level
    //      [Route] on the enclosing type is composed with method-level templates.
    //    - Each `method_declaration` with relevant attributes maps to an
    //      ApiEndpoint path/methods and a HANDLED_BY edge to the Function.
    //
    // 2) ExternalApi + CALLS_EXTERNAL_API:
    //
    // URLs are taken only from string-literal AST nodes (not comments). Each URL
    // is linked only to methods whose body byte range contains that literal
    // (no N×M linking of every method to every URL in the file).
    let endpoints = extract_csharp_api_endpoints_from_tree(&file.tree, source);
    for (methods_http, path_template, handler_name) in endpoints {
        let norm_path = normalize_api_path(&path_template);

        // Create or update the ApiEndpoint node.
        let api_query = query(
            "
            MERGE (api:ApiEndpoint { path: $path })
            ON CREATE SET api.methods      = $methods,
                          api.protocol     = 'http',
                          api.framework    = 'aspnet',
                          api.project_name = $project_name,
                          api.norm_path    = $norm_path
            ON MATCH  SET api.methods      = $methods,
                          api.protocol     = coalesce(api.protocol, 'http'),
                          api.framework    = coalesce(api.framework, 'aspnet'),
                          api.project_name = coalesce(api.project_name, $project_name),
                          api.norm_path    = coalesce(api.norm_path, $norm_path)
            ",
        )
        .param("path", path_template.clone())
        .param("methods", methods_http.clone())
        .param("project_name", project_name.clone())
        .param("norm_path", norm_path.clone());

        graph.run(api_query).await?;

        // Link the endpoint to the matching handler method(s) in this file.
        for func in &methods {
            if func.name != handler_name {
                continue;
            }

            let rel_query = query(
                "
                MERGE (fn:Function { fqn: $fn_fqn })
                MERGE (api:ApiEndpoint { path: $path })
                MERGE (api)-[:HANDLED_BY]->(fn)
                ",
            )
            .param("fn_fqn", func.fqn.clone())
            .param("path", path_template.clone());

            graph.run(rel_query).await?;
        }
    }

    // External APIs called from this file (AST string literals only; per-method edges).
    let url_spans = extract_csharp_external_http_urls_with_spans(&file.tree, source);
    let method_spans = csharp_method_body_spans(&file.tree, source, namespace.as_deref());
    let mut spans_by_fqn: HashMap<String, Vec<(usize, usize)>> = HashMap::new();
    for (fqn, lo, hi) in method_spans {
        spans_by_fqn.entry(fqn).or_default().push((lo, hi));
    }

    for (full_url, u_start, u_end) in url_spans {
        let (protocol_opt, host, path) = split_url_protocol_host_and_path(&full_url);
        let protocol = protocol_opt.unwrap_or_else(|| "http".to_string());
        let base_url = format!("{protocol}://{host}");
        let name = host.clone();
        let norm_path = normalize_api_path(&path);

        let ext_query = query(
            "
            MERGE (ext:ExternalApi { base_url: $base_url, norm_path: $norm_path })
            ON CREATE SET ext.name         = $name,
                          ext.path         = $path,
                          ext.protocol     = $protocol,
                          ext.provider     = $provider,
                          ext.project_name = $project_name
            ON MATCH  SET ext.name         = coalesce(ext.name, $name),
                          ext.path         = coalesce(ext.path, $path),
                          ext.protocol     = coalesce(ext.protocol, $protocol),
                          ext.provider     = coalesce(ext.provider, $provider),
                          ext.project_name = coalesce(ext.project_name, $project_name)
            ",
        )
        .param("name", name.clone())
        .param("base_url", base_url.clone())
        .param("path", path.clone())
        .param("norm_path", norm_path.clone())
        .param("protocol", protocol.clone())
        .param("provider", name.clone())
        .param("project_name", project_name.clone());

        graph.run(ext_query).await?;

        for func in &methods {
            let Some(ranges) = spans_by_fqn.get(&func.fqn) else {
                continue;
            };
            if !ranges
                .iter()
                .any(|(lo, hi)| *lo <= u_start && u_end <= *hi)
            {
                continue;
            }
            accumulator.add_calls_external_api(
                func.fqn.clone(),
                base_url.clone(),
                norm_path.clone(),
            );
        }
    }

    // File-level dependencies from `using` namespaces (same pattern as Java imports).
    for ns in &using_summary.namespace_imports {
        let Some(dep_paths) = csharp_index.namespace_to_paths.get(ns) else {
            continue;
        };
        for dep_path in dep_paths {
            if dep_path == file_path || !known_paths.contains(dep_path) {
                continue;
            }
            let dep_query = query(
                "
                MERGE (src:File { path: $src_path })
                MERGE (dst:File { path: $dst_path })
                MERGE (src)-[:DEPENDS_ON_FILE]->(dst)
                ",
            )
            .param("src_path", file_path.to_string())
            .param("dst_path", dep_path.clone());

            graph.run(dep_query).await?;
        }
    }

    for (derived, base) in extract_csharp_class_inheritance_edges(
        &file.tree,
        source,
        namespace.as_deref(),
        &using_summary,
        csharp_index,
    ) {
        accumulator.add_class_uses_class(derived, base);
    }

    // Accumulate USES_CLASS relationships (global batching)
    let used_classes = extract_csharp_used_classes(
        &file.tree,
        source,
        namespace.as_deref(),
        &using_summary,
        csharp_index,
    );
    for (fn_fqn, class_fqn) in used_classes {
        accumulator.add_uses_class(fn_fqn, class_fqn);
    }

    // Accumulate CALLS_FUNCTION relationships (global batching)
    let calls = extract_csharp_calls(
        &file.tree,
        source,
        namespace.as_deref(),
        &using_summary,
        csharp_index,
    );
    for (caller_fqn, callee_fqn) in calls {
        accumulator.add_calls_function(caller_fqn, callee_fqn);
    }

    Ok(())
}

/// Handle Erlang-specific structure:
/// - Module and function symbols for `.erl` files.
///
/// This implementation is intentionally conservative and uses simple source
/// analysis rather than full Tree-Sitter Erlang walkers. It is good enough
/// to populate:
/// - `(:File)-[:DECLARES_MODULE]->(:Module)`
/// - `(:Module)-[:DECLARES_FUNCTION]->(:Function)`
/// - `(:File)-[:DECLARES_FUNCTION]->(:Function)`
async fn persist_erlang_structure(
    graph: &Graph,
    file: &ParsedFile,
    file_path: String,
    source: &str,
    project_name: Option<String>,
    erlang_module_index: &HashMap<String, ErlangModuleSnapshot>,
    erlang_accumulator: SharedBatchAccumulator,
    compressor: Option<&CompressorClient>,
) -> Result<(), GraphError> {
    let language = file.language.to_string();

    // Resolve module identity with Erlang file-type awareness:
    // - .erl: prefer AST/text module attribute, then basename fallback.
    // - .hrl: never fallback to basename to avoid phantom Module nodes.
    let module_name = resolve_erlang_module_name(&file.path, &file.tree, source);
    let erlang_meta = extract_erlang_behaviour_metadata_from_tree(&file.tree, source);

    // Create/merge the Module node only when we have a resolved module name.
    if let Some(module_name) = module_name.as_ref() {
        let module_code_bytes = match compressor {
            Some(client) => compress_full_source(source, LanguageId::Erlang, client).await,
            None => None,
        };
        let module_query = query(
            "
            MATCH (f:File { path: $path })
            MERGE (m:Module { name: $module_name, path: $path })
            ON CREATE SET m.language = $language,
                          m.project_name = $project_name,
                          m.code_bytes = $code_bytes
            ON MATCH  SET m.language = $language,
                          m.project_name = $project_name,
                          m.code_bytes = coalesce($code_bytes, m.code_bytes)
            MERGE (f)-[:DECLARES_MODULE]->(m)
            ",
        )
        .param("path", file_path.to_string())
        .param("module_name", module_name.clone())
        .param("language", language.clone())
        .param("project_name", project_name.clone())
        .param(props::CODE_BYTES, module_code_bytes);

        graph.run(module_query).await?;
    }

    // Discover function heads in the Erlang source and create Function nodes.
    let functions = if let Some(module_name) = module_name.as_ref() {
        extract_erlang_functions(module_name, &file.tree, source)
    } else {
        Vec::new()
    };
    let function_spans = module_name.as_ref().map(|module_name| {
        extract_erlang_function_spans(module_name, &file.tree, source)
    }).unwrap_or_default();
    // Batch-create Function nodes and DECLARES_FUNCTION edges for better Neo4j throughput.
    if !functions.is_empty() {
        let module_name = module_name.as_ref().expect("module must exist when functions exist");
        // Prepare parallel arrays for Cypher UNWIND; this avoids sending a list of maps
        // and keeps the parameter typing simple for neo4rs.
        let mut fn_fqns: Vec<String> = Vec::with_capacity(functions.len());
        let mut fn_names: Vec<String> = Vec::with_capacity(functions.len());
        let mut fn_arities: Vec<i64> = Vec::with_capacity(functions.len());
        let mut code_bytes_list: Vec<Option<Vec<u8>>> = Vec::with_capacity(functions.len());

        for (fun_name, arity, fqn) in &functions {
            fn_fqns.push(fqn.clone());
            fn_names.push(fun_name.clone());
            fn_arities.push(*arity as i64);
            code_bytes_list.push(
                code_bytes_for_span(
                    compressor,
                    source,
                    function_spans.get(fqn).copied(),
                    LanguageId::Erlang,
                )
                .await,
            );
        }

        let fun_query = query(
            "
            MATCH (f:File { path: $path })
            MATCH (m:Module { name: $module_name, path: $path })
            WITH f, m,
                 $fn_fqns   AS fn_fqns,
                 $fn_names  AS fn_names,
                 $fn_arities AS fn_arities,
                 $code_bytes_list AS code_bytes_list,
                 $language  AS language,
                 $path      AS path,
                 $project_name AS project_name
            UNWIND range(0, size(fn_fqns) - 1) AS idx
            WITH f, m, language, path, project_name,
                 fn_fqns[idx]   AS fn_fqn,
                 fn_names[idx]  AS fn_name,
                 fn_arities[idx] AS arity,
                 code_bytes_list[idx] AS code_bytes
            MERGE (fn:Function { fqn: fn_fqn })
            ON CREATE SET fn.name = fn_name,
                          fn.path = path,
                          fn.language = language,
                          fn.project_name = project_name,
                          fn.arity = arity,
                          fn.code_bytes = code_bytes
            ON MATCH  SET fn.name = fn_name,
                          fn.path = path,
                          fn.language = language,
                          fn.project_name = project_name,
                          fn.arity = arity,
                          fn.code_bytes = coalesce(code_bytes, fn.code_bytes)
            MERGE (f)-[:DECLARES_FUNCTION]->(fn)
            MERGE (m)-[:DECLARES_FUNCTION]->(fn)
            ",
        )
        .param("path", file_path.to_string())
        .param("module_name", module_name.clone())
        .param("language", language.clone())
        .param("fn_fqns", fn_fqns)
        .param("fn_names", fn_names)
        .param("fn_arities", fn_arities)
        .param("code_bytes_list", code_bytes_list)
        .param("project_name", project_name.clone());

        graph.run(fun_query).await?;
    }

    // Build callback contract candidates from locally declared behaviour
    // callbacks and known OTP behaviour signatures.
    let callback_contracts = collect_callback_contracts_for_module(
        module_name.as_deref(),
        &erlang_meta.behaviour_usages,
        &erlang_meta.declared_callbacks,
        &erlang_meta.optional_callbacks,
    );

    if let Some(module_name) = module_name.as_ref() {
        // Module -> IMPLEMENTS_BEHAVIOUR -> Behaviour
        for behaviour in &erlang_meta.behaviour_usages {
            let behaviour_query = query(
                "
                MATCH (m:Module { name: $module_name, path: $path })
                MERGE (b:Behaviour { name: $behaviour })
                ON CREATE SET b.language = $language,
                              b.project_name = $project_name
                ON MATCH  SET b.language = coalesce(b.language, $language),
                              b.project_name = coalesce(b.project_name, $project_name)
                MERGE (m)-[:IMPLEMENTS_BEHAVIOUR]->(b)
                ",
            )
            .param("module_name", module_name.clone())
            .param("path", file_path.to_string())
            .param("behaviour", behaviour.clone())
            .param("language", language.clone())
            .param("project_name", project_name.clone());
            graph.run(behaviour_query).await?;

            // Module -> DEPENDS_ON_FILE -> File for custom behaviour files.
            // We use same-directory module-to-file guess to keep behavior
            // consistent with existing Erlang dependency heuristics.
            let dep_path = guess_erlang_file_path_from_module(&file_path, behaviour);
            let module_dep_query = query(
                "
                MATCH (m:Module { name: $module_name, path: $path })
                MERGE (dst:File { path: $dst_path })
                MERGE (m)-[:DEPENDS_ON_FILE]->(dst)
                ",
            )
            .param("module_name", module_name.clone())
            .param("path", file_path.to_string())
            .param("dst_path", dep_path);
            graph.run(module_dep_query).await?;
        }

        // If callbacks are declared in this module, treat it as a behaviour
        // declaration source for traceability.
        if !erlang_meta.declared_callbacks.is_empty() {
            let file_declares_behaviour_query = query(
                "
                MATCH (f:File { path: $path })
                MERGE (b:Behaviour { name: $behaviour })
                ON CREATE SET b.path = $path,
                              b.language = $language,
                              b.project_name = $project_name
                ON MATCH  SET b.path = coalesce(b.path, $path),
                              b.language = coalesce(b.language, $language),
                              b.project_name = coalesce(b.project_name, $project_name)
                MERGE (f)-[:DECLARES_BEHAVIOUR]->(b)
                ",
            )
            .param("path", file_path.to_string())
            .param("behaviour", module_name.clone())
            .param("language", language.clone())
            .param("project_name", project_name.clone());
            graph.run(file_declares_behaviour_query).await?;
        }

        // Behaviour -> EXTENDS_BEHAVIOUR -> Behaviour
        for parent_behaviour in &erlang_meta.behaviour_extensions {
            let extends_query = query(
                "
                MERGE (child:Behaviour { name: $child })
                MERGE (parent:Behaviour { name: $parent })
                MERGE (child)-[:EXTENDS_BEHAVIOUR]->(parent)
                ",
            )
            .param("child", module_name.clone())
            .param("parent", parent_behaviour.clone());
            graph.run(extends_query).await?;
        }
    }

    // Persist callback contracts and behaviour declarations.
    for contract in &callback_contracts {
        let callback_fqn = format!(
            "{behaviour}:{name}/{arity}",
            behaviour = contract.behaviour,
            name = contract.name,
            arity = contract.arity
        );
        let callback_query = query(
            "
            MERGE (b:Behaviour { name: $behaviour })
            MERGE (cb:Callback { fqn: $cb_fqn })
            ON CREATE SET cb.name = $cb_name,
                          cb.arity = $cb_arity,
                          cb.optional = $cb_optional,
                          cb.language = $language,
                          cb.project_name = $project_name
            ON MATCH  SET cb.name = coalesce(cb.name, $cb_name),
                          cb.arity = coalesce(cb.arity, $cb_arity),
                          cb.optional = $cb_optional,
                          cb.language = coalesce(cb.language, $language),
                          cb.project_name = coalesce(cb.project_name, $project_name)
            MERGE (b)-[:DECLARES_CALLBACK]->(cb)
            ",
        )
        .param("behaviour", contract.behaviour.clone())
        .param("cb_fqn", callback_fqn.clone())
        .param("cb_name", contract.name.clone())
        .param("cb_arity", contract.arity as i64)
        .param("cb_optional", contract.optional)
        .param("language", language.clone())
        .param("project_name", project_name.clone());
        graph.run(callback_query).await?;
    }

    // Function -> IMPLEMENTS_CALLBACK and advanced explicit
    // Function -> OVERRIDES_CALLBACK relations.
    let function_by_sig: HashMap<(String, u32), String> = functions
        .iter()
        .map(|(name, arity, fqn)| ((name.clone(), *arity), fqn.clone()))
        .collect();

    for contract in &callback_contracts {
        let key = (contract.name.clone(), contract.arity);
        let Some(fn_fqn) = function_by_sig.get(&key) else {
            continue;
        };

        let callback_fqn = format!(
            "{behaviour}:{name}/{arity}",
            behaviour = contract.behaviour,
            name = contract.name,
            arity = contract.arity
        );
        let implements_query = query(
            "
            MERGE (fn:Function { fqn: $fn_fqn })
            MERGE (cb:Callback { fqn: $cb_fqn })
            MERGE (fn)-[:IMPLEMENTS_CALLBACK]->(cb)
            ",
        )
        .param("fn_fqn", fn_fqn.clone())
        .param("cb_fqn", callback_fqn.clone());
        graph.run(implements_query).await?;
    }

    // Guarded override relation: create only for explicit -override_callback.
    for (name, arity) in erlang_meta.overridden_callbacks {
        let key = (name.clone(), arity);
        let Some(fn_fqn) = function_by_sig.get(&key) else {
            continue;
        };
        for contract in callback_contracts
            .iter()
            .filter(|c| c.name == name && c.arity == arity)
        {
            let callback_fqn = format!(
                "{behaviour}:{name}/{arity}",
                behaviour = contract.behaviour,
                name = contract.name,
                arity = contract.arity
            );
            let overrides_query = query(
                "
                MERGE (fn:Function { fqn: $fn_fqn })
                MERGE (cb:Callback { fqn: $cb_fqn })
                MERGE (fn)-[:OVERRIDES_CALLBACK]->(cb)
                ",
            )
            .param("fn_fqn", fn_fqn.clone())
            .param("cb_fqn", callback_fqn);
            graph.run(overrides_query).await?;
        }
    }

    // Best-effort extraction of Cowboy API endpoints inside this module.
    //
    // Previous behavior only linked ApiEndpoint -> Function when the router
    // module name matched the handler module name. That missed the common
    // pattern where a dedicated router module points at a separate handler
    // module. We now always link the ApiEndpoint to well-known handler
    // callbacks (`init/2` and `handle/2`) on the referenced handler module.
    let endpoints = extract_erlang_api_endpoints(&file.tree, source);
    for (methods, path_template, handler_module) in endpoints {
        let norm_path = normalize_api_path(&path_template);

        // Create or update the ApiEndpoint node.
        let api_query = query(
            "
            MERGE (api:ApiEndpoint { path: $path })
            ON CREATE SET api.methods      = $methods,
                          api.protocol     = 'http',
                          api.framework    = 'cowboy',
                          api.project_name = $project_name,
                          api.norm_path    = $norm_path
            ON MATCH  SET api.methods      = $methods,
                          api.protocol     = coalesce(api.protocol, 'http'),
                          api.framework    = coalesce(api.framework, 'cowboy'),
                          api.project_name = coalesce(api.project_name, $project_name),
                          api.norm_path    = coalesce(api.norm_path, $norm_path)
            ",
        )
        .param("path", path_template.clone())
        .param("methods", methods.clone())
        .param("project_name", project_name.clone())
        .param("norm_path", norm_path.clone());

        graph.run(api_query).await?;

        // Strict precision mode:
        // - Derive callback signatures from AST behaviour/callback contracts.
        // - Link only callbacks that are actually implemented in the handler module.
        let candidate_fqns = select_endpoint_handler_fqns(&handler_module, erlang_module_index);
        for fqn in candidate_fqns {
            let rel_query = query(
                "
                MERGE (fn:Function { fqn: $fn_fqn })
                MERGE (api:ApiEndpoint { path: $path })
                MERGE (api)-[:HANDLED_BY]->(fn)
                ",
            )
            .param("fn_fqn", fqn)
            .param("path", path_template.clone());

            graph.run(rel_query).await?;
        }
    }

    // Best-effort extraction of external HTTP APIs referenced in this module.
    //
    // We now retain both the base_url (scheme://host) and the path so that
    // downstream queries can join Omega ApiEndpoints to CAPI ExternalApi
    // nodes on full API identity (host + path).
    let external_urls = extract_external_http_urls_from_tree(&file.tree, source);
    for full_url in external_urls {
        let (protocol_opt, host, path) = split_url_protocol_host_and_path(&full_url);
        let protocol = protocol_opt.unwrap_or_else(|| "http".to_string());
        let base_url = format!("{protocol}://{host}");
        let name = host.clone();
        let norm_path = normalize_api_path(&path);

        let ext_query = query(
            "
            MERGE (ext:ExternalApi { base_url: $base_url, norm_path: $norm_path })
            ON CREATE SET ext.name         = $name,
                          ext.path         = $path,
                          ext.protocol     = $protocol,
                          ext.provider     = $provider,
                          ext.project_name = $project_name
            ON MATCH  SET ext.name         = coalesce(ext.name, $name),
                          ext.path         = coalesce(ext.path, $path),
                          ext.protocol     = coalesce(ext.protocol, $protocol),
                          ext.provider     = coalesce(ext.provider, $provider),
                          ext.project_name = coalesce(ext.project_name, $project_name)
            ",
        )
        .param("name", name.clone())
        .param("base_url", base_url.clone())
        .param("path", path.clone())
        .param("norm_path", norm_path.clone())
        .param("protocol", protocol.clone())
        .param("provider", name.clone())
        .param("project_name", project_name.clone());

        graph.run(ext_query).await?;

        // Link all functions in this module to the external API. We still keep
        // conservative function-to-URL coverage, but relationship persistence is
        // batched through the shared accumulator for higher throughput.
        if !functions.is_empty() {
            let mut guard = erlang_accumulator.lock().await;
            for (_fun_name, _arity, fqn) in &functions {
                guard.add_calls_external_api(fqn.clone(), base_url.clone(), norm_path.clone());
            }
        }
    }

    // Intra-module function call graph for Erlang.
    //
    // Build CALLS_FUNCTION edges from AST call sites by resolving:
    // - caller from the enclosing function_clause
    // - callee from local call expression + arity
    //
    // This records only observed caller->callee pairs and avoids the old
    // module-wide N*M over-approximation.
    let function_by_sig: HashMap<(String, u32), String> = functions
        .iter()
        .map(|(name, arity, fqn)| ((name.clone(), *arity), fqn.clone()))
        .collect();
    let call_edges: Vec<(String, String)> = extract_erlang_call_edges(
        &file.tree,
        source,
        module_name.as_deref(),
        &function_by_sig,
    )
    .into_iter()
    .collect();

    if !call_edges.is_empty() {
        let mut guard = erlang_accumulator.lock().await;
        for (caller_fqn, callee_fqn) in call_edges {
            guard.add_calls_function(caller_fqn, callee_fqn);
        }
    }

    // File-level dependencies for Erlang based on module calls.
    //
    // Whenever this module calls AnotherModule:fun(...), we create a
    // DEPENDS_ON_FILE edge from this file to the guessed file path for
    // AnotherModule (e.g. same directory with `.erl` extension).
    let called_modules = extract_erlang_called_modules_from_tree(&file.tree, source);
    for callee_mod in called_modules {
        if module_name.as_deref() == Some(callee_mod.as_str()) {
            continue;
        }
        let dep_path = guess_erlang_file_path_from_module(&file_path, &callee_mod);
        let dep_query = query(
            "
            MERGE (src:File { path: $src_path })
            MERGE (dst:File { path: $dst_path })
            MERGE (src)-[:DEPENDS_ON_FILE]->(dst)
            ",
        )
        .param("src_path", file_path.to_string())
        .param("dst_path", dep_path);

        graph.run(dep_query).await?;

        if let Some(module_name) = module_name.as_ref() {
            let module_dep_query = query(
                "
                MATCH (m:Module { name: $module_name, path: $path })
                MERGE (dst:File { path: $dst_path })
                MERGE (m)-[:DEPENDS_ON_FILE]->(dst)
                ",
            )
            .param("module_name", module_name.clone())
            .param("path", file_path.to_string())
            .param(
                "dst_path",
                guess_erlang_file_path_from_module(&file_path, &callee_mod),
            );

            graph.run(module_dep_query).await?;
        }
    }

    Ok(())
}

/// For non-Java languages, extract top-level functions and link them to their
/// files. This makes the graph usable for functional queries even in
/// non-class-based codebases (e.g. Python, JS).
async fn persist_non_java_functions(
    graph: &Graph,
    file_path: &str,
    file: &ParsedFile,
    source: &str,
    project_name: Option<String>,
    known_paths: &HashSet<String>,
    accumulator: &mut BatchAccumulator,
    persistence: &GraphPersistenceOptions,
    compressor: Option<&CompressorClient>,
) -> Result<(), GraphError> {
    let language = file.language.to_string();

    match file.language {
        LanguageId::Python => {
            emit_limited_parse_warnings(
                "Python",
                file_path,
                extract_python_parse_warnings(&file.tree, source),
                persistence.max_parse_warnings_per_file,
            );
        }
        LanguageId::JavaScript | LanguageId::TypeScript | LanguageId::Tsx => {
            emit_limited_parse_warnings(
                "JS/TS",
                file_path,
                extract_js_ts_parse_warnings(&file.tree, source),
                persistence.max_parse_warnings_per_file,
            );
        }
        _ => {}
    }

    let functions = extract_non_java_function_symbols(file, source, file_path);
    let function_spans = extract_non_java_function_body_spans(file, source, file_path);

    let mut name_to_fqn_depth: HashMap<String, (String, usize)> = HashMap::new();
    for f in &functions {
        let logical = f
            .fqn
            .split_once("::")
            .map(|(_, l)| l)
            .unwrap_or(f.fqn.as_str());
        let (short, depth) = non_java_short_name_and_depth(file.language, logical);
        name_to_fqn_depth
            .entry(short)
            .and_modify(|(existing_fqn, existing_depth)| {
                if depth > *existing_depth {
                    *existing_fqn = f.fqn.clone();
                    *existing_depth = depth;
                }
            })
            .or_insert_with(|| (f.fqn.clone(), depth));
    }
    let name_to_fqn: HashMap<String, String> = name_to_fqn_depth
        .into_iter()
        .map(|(k, (v, _))| (k, v))
        .collect();

    for func in &functions {
        let code_bytes = code_bytes_for_span(
            compressor,
            source,
            function_spans.get(&func.fqn).copied(),
            file.language,
        )
        .await;
        let q = query(
            "
            MATCH (f:File { path: $path })
            MERGE (fn:Function { fqn: $fn_fqn })
            ON CREATE SET fn.name = $fn_name,
                          fn.path = $path,
                          fn.project_name = $project_name,
                          fn.language = $language,
                          fn.code_bytes = $code_bytes
            ON MATCH SET  fn.name = $fn_name,
                          fn.path = $path,
                          fn.project_name = $project_name,
                          fn.language = $language,
                          fn.code_bytes = coalesce($code_bytes, fn.code_bytes)
            MERGE (f)-[:DECLARES_FUNCTION]->(fn)
            ",
        )
        .param("path", file_path.to_string())
        .param("fn_fqn", func.fqn.clone())
        .param("fn_name", func.name.clone())
        .param("project_name", project_name.clone())
        .param("language", language.clone())
        .param(props::CODE_BYTES, code_bytes);

        graph.run(q).await?;
    }

    match file.language {
        LanguageId::Python => {
            for imp in extract_python_import_modules(&file.tree, source) {
                if let Some(dep) = resolve_python_import_to_known_file(&imp, known_paths) {
                    let dep_query = query(
                        "
                        MERGE (src:File { path: $src_path })
                        MERGE (dst:File { path: $dst_path })
                        MERGE (src)-[:DEPENDS_ON_FILE]->(dst)
                        ",
                    )
                    .param("src_path", file_path.to_string())
                    .param("dst_path", dep.clone());
                    graph.run(dep_query).await?;
                } else if should_log_unresolved_import(
                    persistence.verbose_imports,
                    is_python_stdlib_top_level(&imp),
                    is_python_common_external_top_level(&imp),
                ) {
                    println!(
                        "Python import (unresolved to scanned files): `{}` in {}",
                        imp, file_path
                    );
                }
            }
            for (caller, callee) in extract_python_intrafile_calls(
                &file.tree,
                source,
                file_path,
                &name_to_fqn,
            ) {
                accumulator.add_calls_function(caller, callee);
            }
        }
        LanguageId::JavaScript | LanguageId::TypeScript | LanguageId::Tsx => {
            for spec in extract_js_ts_import_specifiers(&file.tree, source) {
                if let Some(dep) =
                    resolve_js_ts_import_to_known_file(&spec, file_path, known_paths)
                {
                    let dep_query = query(
                        "
                        MERGE (src:File { path: $src_path })
                        MERGE (dst:File { path: $dst_path })
                        MERGE (src)-[:DEPENDS_ON_FILE]->(dst)
                        ",
                    )
                    .param("src_path", file_path.to_string())
                    .param("dst_path", dep.clone());
                    graph.run(dep_query).await?;
                } else if persistence.verbose_imports {
                    println!(
                        "JS/TS import (unresolved to scanned files): `{}` in {}",
                        spec, file_path
                    );
                }
            }
            for (caller, callee) in extract_js_ts_intrafile_calls(
                &file.tree,
                source,
                file_path,
                file.language,
                &name_to_fqn,
            ) {
                accumulator.add_calls_function(caller, callee);
            }
        }
        LanguageId::Rust => {
            for use_path in extract_rust_use_paths(&file.tree, source) {
                if let Some(dep) =
                    resolve_rust_use_to_known_file(&use_path, file_path, known_paths)
                {
                    let dep_query = query(
                        "
                        MERGE (src:File { path: $src_path })
                        MERGE (dst:File { path: $dst_path })
                        MERGE (src)-[:DEPENDS_ON_FILE]->(dst)
                        ",
                    )
                    .param("src_path", file_path.to_string())
                    .param("dst_path", dep.clone());
                    graph.run(dep_query).await?;
                } else if persistence.verbose_imports {
                    println!(
                        "Rust use (unresolved to scanned files): `{}` in {}",
                        use_path.join("::"),
                        file_path
                    );
                }
            }
            for (caller, callee) in
                extract_rust_intrafile_calls(&file.tree, source, file_path, &name_to_fqn)
            {
                accumulator.add_calls_function(caller, callee);
            }
        }
        _ => {}
    }

    Ok(())
}

/// Extract internal Java imports from a source file.
///
/// We treat any line that looks like:
///     import com.redbus.genai.some.package.Type;
///
/// as an internal dependency and return the fully-qualified name
/// `com.redbus.genai.some.package.Type`.
fn extract_internal_java_imports(source: &str) -> Vec<String> {
    source
        .lines()
        .filter_map(|line| {
            let line = line.trim();
            // Ignore non-import lines quickly.
            if !line.starts_with("import ") || !line.ends_with(';') {
                return None;
            }

            // Strip the leading "import " and trailing ';'.
            let body = &line["import ".len()..line.len() - 1];
            let body = body.trim();

            // Skip static imports like "import static com.foo.Bar.baz;"
            let body = body.strip_prefix("static ").map(str::trim).unwrap_or(body);

            // Only keep internal project imports.
            if !body.starts_with("com.redbus.genai.") {
                return None;
            }

            Some(body.to_string())
        })
        .collect()
}

/// Map a Java import FQN (e.g. `com.redbus.genai.model.Foo`) to a project
/// relative file path string that matches how the scanner recorded it.
///
/// We do this by:
/// - Finding the `com/redbus/genai/` segment in the current file's path.
/// - Replacing '.' with '/' in the import FQN and appending ".java".
/// - Prefixing that relative path with the part of the current file path
///   that comes before `com/redbus/genai/`.
fn map_import_to_project_path(current_path: &str, import_fqn: &str) -> Option<String> {
    let marker = "com/redbus/genai/";
    let idx = current_path.find(marker)?;
    let prefix = &current_path[..idx];

    let relative = import_fqn.replace('.', "/") + ".java";
    Some(format!("{prefix}{relative}"))
}

/// Extract the Java package name from a source file, if present.
fn extract_java_package(source: &str) -> Option<String> {
    for line in source.lines() {
        let line = line.trim();
        if !line.starts_with("package ") || !line.ends_with(';') {
            continue;
        }

        let body = &line["package ".len()..line.len() - 1];
        let body = body.trim();
        if body.is_empty() {
            continue;
        }
        return Some(body.to_string());
    }
    None
}

/// Extract the Erlang module name from source, if there is a `-module(Name).`
/// attribute. Falls back to None if not present.
fn extract_erlang_module_name(source: &str) -> Option<String> {
    for line in source.lines() {
        let line = line.trim();
        if !line.starts_with("-module(") || !line.ends_with(").") {
            continue;
        }

        let inner = &line["-module(".len()..line.len() - 2]; // strip "-module(" and ")."
        let name = inner.trim();
        if !name.is_empty() {
            return Some(name.to_string());
        }
    }
    None
}

/// Extract the Erlang module name from the Tree-Sitter AST, if present.
fn extract_erlang_module_name_from_tree(tree: &Tree, source: &str) -> Option<String> {
    let mut out: Option<String> = None;
    let root = tree.root_node();

    walk_tree(root, |node| {
        if out.is_some() || node.kind() != "module_attribute" {
            return;
        }
        if let Some(name_node) = node.child_by_field_name("name") {
            let start = name_node.start_byte() as usize;
            let end = name_node.end_byte() as usize;
            if end <= source.len() && start < end {
                let name = source[start..end].trim().trim_matches('\'').to_string();
                if !name.is_empty() {
                    out = Some(name);
                }
            }
        }
    });

    out
}

fn is_erlang_header_file(path: &Path) -> bool {
    path.extension()
        .and_then(|ext| ext.to_str())
        .map(|ext| ext.eq_ignore_ascii_case("hrl"))
        .unwrap_or(false)
}

/// Resolve module name with file-type-aware fallback policy.
///
/// - `.erl`: AST/text attribute first, then basename fallback.
/// - `.hrl`: AST/text attribute only (no basename fallback).
fn resolve_erlang_module_name(path: &Path, tree: &Tree, source: &str) -> Option<String> {
    if let Some(module_name) = extract_erlang_module_name_from_tree(tree, source)
        .or_else(|| extract_erlang_module_name(source))
    {
        return Some(module_name);
    }

    if is_erlang_header_file(path) {
        None
    } else {
        Some(guess_erlang_module_name_from_path(&path.display().to_string()))
    }
}

/// Guess an Erlang module name from the file path if there is no explicit
/// `-module(Name).` attribute.
fn guess_erlang_module_name_from_path(path: &str) -> String {
    Path::new(path)
        .file_stem()
        .and_then(|s| s.to_str())
        .unwrap_or("unknown_module")
        .to_string()
}

fn extract_erlang_behaviour_metadata_from_tree(tree: &Tree, source: &str) -> ErlangBehaviourMetadata {
    let mut meta = ErlangBehaviourMetadata::default();
    let mut seen_declared_callbacks: HashSet<(String, u32)> = HashSet::new();
    let root = tree.root_node();

    walk_tree(root, |node| match node.kind() {
        "behaviour_attribute" => {
            if let Some(name_node) = node.child_by_field_name("name") {
                if let Some(name) = extract_erlang_name(name_node, source) {
                    meta.behaviour_usages.insert(name);
                }
            }
        }
        "callback" => {
            let Some(fun_node) = node.child_by_field_name("fun") else {
                return;
            };
            let Some(fun_name) = extract_erlang_name(fun_node, source) else {
                return;
            };

            let mut cursor = node.walk();
            for sig_node in node.children_by_field_name("sigs", &mut cursor) {
                let Some(args_node) = sig_node.child_by_field_name("args") else {
                    continue;
                };
                let key = (fun_name.clone(), args_node.named_child_count() as u32);
                if seen_declared_callbacks.insert(key.clone()) {
                    meta.declared_callbacks.push(key);
                }
            }
        }
        "optional_callbacks_attribute" => {
            let mut cursor = node.walk();
            for fa_node in node.children_by_field_name("callbacks", &mut cursor) {
                if let Some((name, arity)) = extract_erlang_fa_pair(fa_node, source) {
                    meta.optional_callbacks.insert((name, arity));
                }
            }
        }
        "wild_attribute" => {
            let Some(attr_node) = node.child_by_field_name("name") else {
                return;
            };
            let Some(attr_name) = extract_wild_attribute_name(attr_node, source) else {
                return;
            };
            let Some(value_node) = node.child_by_field_name("value") else {
                return;
            };

            match attr_name.as_str() {
                "extends_behaviour" => {
                    if let Some(parent_behaviour) = extract_single_name_expr(value_node, source) {
                        meta.behaviour_extensions.insert(parent_behaviour);
                    }
                }
                "override_callback" => {
                    let mut pairs: HashSet<(String, u32)> = HashSet::new();
                    walk_tree(value_node, |child| {
                        if child.kind() == "fa" {
                            if let Some((name, arity)) = extract_erlang_fa_pair(child, source) {
                                pairs.insert((name, arity));
                            }
                        }
                    });
                    if pairs.is_empty() {
                        if let Some(raw_value) = node_text(value_node, source) {
                            pairs.extend(parse_fa_pairs_from_expr_text(raw_value));
                        }
                    }
                    meta.overridden_callbacks.extend(pairs);
                }
                _ => {}
            }
        }
        _ => {}
    });

    meta
}

fn extract_wild_attribute_name(attr_node: Node, source: &str) -> Option<String> {
    let name_node = attr_node.child_by_field_name("name").unwrap_or(attr_node);
    let mut name = extract_erlang_name(name_node, source)?;
    if let Some(stripped) = name.strip_prefix('-') {
        name = stripped.to_string();
    }
    Some(name)
}

fn extract_erlang_fa_pair(fa_node: Node, source: &str) -> Option<(String, u32)> {
    if fa_node.kind() != "fa" {
        return None;
    }
    let fun_node = fa_node.child_by_field_name("fun")?;
    let arity_node = fa_node.child_by_field_name("arity")?;

    let fun_name = extract_erlang_name(fun_node, source)?;
    let raw_arity = node_text(arity_node, source)?;
    let arity = parse_erlang_arity(raw_arity)?;
    Some((fun_name, arity))
}

fn parse_erlang_arity(raw: &str) -> Option<u32> {
    raw.trim().trim_start_matches('/').parse::<u32>().ok()
}

fn extract_single_name_expr(node: Node, source: &str) -> Option<String> {
    let mut raw = node_text(node, source)?.trim();
    while raw.starts_with('(') && raw.ends_with(')') && raw.len() >= 2 {
        raw = raw[1..raw.len() - 1].trim();
    }
    normalize_erlang_name(raw)
}

fn parse_fa_pairs_from_expr_text(expr_text: &str) -> HashSet<(String, u32)> {
    let mut out = HashSet::new();
    let mut raw = expr_text.trim();
    while raw.starts_with('(') && raw.ends_with(')') && raw.len() >= 2 {
        raw = raw[1..raw.len() - 1].trim();
    }

    for token in raw.split(',') {
        let token = token.trim();
        let Some((name_raw, arity_raw)) = token.split_once('/') else {
            continue;
        };
        let Some(name) = normalize_erlang_name(name_raw) else {
            continue;
        };
        let Some(arity) = parse_erlang_arity(arity_raw) else {
            continue;
        };
        out.insert((name, arity));
    }

    out
}

fn extract_erlang_name(node: Node, source: &str) -> Option<String> {
    let raw = node_text(node, source)?;
    normalize_erlang_name(raw)
}

fn node_text<'a>(node: Node, source: &'a str) -> Option<&'a str> {
    let start = node.start_byte() as usize;
    let end = node.end_byte() as usize;
    if end <= source.len() && start < end {
        Some(&source[start..end])
    } else {
        None
    }
}

fn normalize_erlang_name(raw: &str) -> Option<String> {
    let mut name = raw.trim();
    if name.starts_with('\'') && name.ends_with('\'') && name.len() >= 2 {
        name = &name[1..name.len() - 1];
    }
    if name.is_empty() {
        return None;
    }
    if name.starts_with('?') {
        return None;
    }
    if name
        .chars()
        .next()
        .map(|c| c.is_ascii_uppercase())
        .unwrap_or(false)
    {
        return None;
    }
    if name.chars().any(char::is_whitespace) {
        return None;
    }
    Some(name.to_string())
}

fn known_behaviour_callbacks(behaviour: &str) -> &'static [(&'static str, u32)] {
    match behaviour {
        "gen_server" => &[
            ("init", 1),
            ("handle_call", 3),
            ("handle_cast", 2),
            ("handle_info", 2),
            ("terminate", 2),
            ("code_change", 3),
            ("format_status", 2),
        ],
        "supervisor" => &[("init", 1)],
        "gen_statem" => &[
            ("init", 1),
            ("callback_mode", 0),
            ("state_name", 3),
            ("state_name", 2),
            ("terminate", 3),
            ("code_change", 4),
            ("format_status", 2),
        ],
        "cowboy_handler" => &[("init", 2)],
        "cowboy_loop" => &[("init", 2), ("info", 3), ("terminate", 3)],
        "cowboy_websocket" => &[
            ("init", 2),
            ("websocket_init", 1),
            ("websocket_handle", 2),
            ("websocket_info", 2),
            ("terminate", 3),
        ],
        "cowboy_rest" => &[
            ("init", 2),
            ("allowed_methods", 2),
            ("content_types_provided", 2),
            ("content_types_accepted", 2),
            ("resource_exists", 2),
            ("is_authorized", 2),
            ("forbidden", 2),
            ("malformed_request", 2),
            ("delete_resource", 2),
            ("generate_etag", 2),
            ("last_modified", 2),
        ],
        _ => &[],
    }
}

fn collect_callback_contracts_for_module(
    module_name: Option<&str>,
    behaviour_usages: &HashSet<String>,
    declared_callbacks: &[(String, u32)],
    optional_callbacks: &HashSet<(String, u32)>,
) -> Vec<CallbackContract> {
    let mut contracts = HashSet::new();

    // Contracts declared by this module when it is itself a behaviour.
    if let Some(module_name) = module_name {
        for (name, arity) in declared_callbacks {
            contracts.insert(CallbackContract {
                behaviour: module_name.to_string(),
                name: name.clone(),
                arity: *arity,
                optional: optional_callbacks.contains(&(name.clone(), *arity)),
            });
        }
    }

    // Known OTP callback sets for behaviours implemented by this module.
    for behaviour in behaviour_usages {
        for (name, arity) in known_behaviour_callbacks(behaviour) {
            contracts.insert(CallbackContract {
                behaviour: behaviour.clone(),
                name: (*name).to_string(),
                arity: *arity,
                optional: false,
            });
        }
    }

    contracts.into_iter().collect()
}

fn select_endpoint_handler_fqns(
    handler_module: &str,
    erlang_module_index: &HashMap<String, ErlangModuleSnapshot>,
) -> Vec<String> {
    let Some(snapshot) = erlang_module_index.get(handler_module) else {
        return Vec::new();
    };

    let mut fqns: Vec<String> = snapshot
        .callback_signatures
        .iter()
        .filter(|sig| snapshot.implemented_signatures.contains(*sig))
        .map(|(name, arity)| format!("{module}:{name}/{arity}", module = handler_module))
        .collect();

    fqns.sort();
    fqns.dedup();
    fqns
}

/// Extract Erlang top-level function signatures from AST `function_clause` nodes.
///
/// We intentionally only capture clauses that are direct children of the
/// source file to avoid picking up anonymous `fun` clauses.
fn extract_erlang_functions(
    module_name: &str,
    tree: &Tree,
    source: &str,
) -> Vec<(String, u32, String)> {
    let mut seen: HashSet<(String, u32)> = HashSet::new();
    let mut out: Vec<(String, u32, String)> = Vec::new();

    let root = tree.root_node();
    walk_tree(root, |node| {
        if node.kind() != "function_clause" || !is_top_level_erlang_function_clause(node) {
            return;
        }

        let Some(name_node) = node.child_by_field_name("name") else {
            return;
        };
        let Some(fun_name) = extract_erlang_name(name_node, source) else {
            return;
        };
        let Some(args_node) = node.child_by_field_name("args") else {
            return;
        };
        let arity = args_node.named_child_count() as u32;

        if seen.insert((fun_name.clone(), arity)) {
            let fqn = format!("{module}:{name}/{arity}", module = module_name, name = fun_name);
            out.push((fun_name, arity, fqn));
        }
    });

    out
}

fn is_top_level_erlang_function_clause(node: Node) -> bool {
    let mut parent = node.parent();
    let mut has_source_file_ancestor = false;
    while let Some(p) = parent {
        match p.kind() {
            // Anonymous function clauses should not be treated as module-level
            // declared functions.
            "fun_expr" => return false,
            "source_file" => {
                has_source_file_ancestor = true;
                break;
            }
            _ => {
                parent = p.parent();
            }
        }
    }
    has_source_file_ancestor
}

fn extract_erlang_call_edges(
    tree: &Tree,
    source: &str,
    module_name: Option<&str>,
    function_by_sig: &HashMap<(String, u32), String>,
) -> HashSet<(String, String)> {
    let Some(module_name) = module_name else {
        return HashSet::new();
    };
    let mut edges = HashSet::new();
    let root = tree.root_node();

    walk_tree(root, |node| {
        if node.kind() != "call" {
            return;
        }
        let Some(caller_clause) = find_enclosing_function_clause(node) else {
            return;
        };
        let Some(caller_name_node) = caller_clause.child_by_field_name("name") else {
            return;
        };
        let Some(caller_name) = extract_erlang_name(caller_name_node, source) else {
            return;
        };
        let Some(caller_args) = caller_clause.child_by_field_name("args") else {
            return;
        };
        let caller_arity = caller_args.named_child_count() as u32;
        let Some(caller_fqn) = function_by_sig.get(&(caller_name, caller_arity)) else {
            return;
        };

        let Some(call_expr) = node.child_by_field_name("expr") else {
            return;
        };
        let Some(call_args) = node.child_by_field_name("args") else {
            return;
        };
        let callee_arity = call_args.named_child_count() as u32;
        let Some(callee_name) = extract_local_call_name(call_expr, source) else {
            return;
        };

        let callee_key = (callee_name, callee_arity);
        let Some(callee_fqn) = function_by_sig.get(&callee_key) else {
            return;
        };
        if caller_fqn != callee_fqn && caller_fqn.starts_with(module_name) && callee_fqn.starts_with(module_name) {
            edges.insert((caller_fqn.clone(), callee_fqn.clone()));
        }
    });

    edges
}

fn find_enclosing_function_clause(node: Node) -> Option<Node> {
    let mut cur = node.parent();
    while let Some(parent) = cur {
        if parent.kind() == "function_clause" {
            return Some(parent);
        }
        if parent.kind() == "source_file" {
            break;
        }
        cur = parent.parent();
    }
    None
}

fn extract_local_call_name(expr_node: Node, source: &str) -> Option<String> {
    match expr_node.kind() {
        // Local calls: foo(...)
        "_name" | "atom" | "var" => extract_erlang_name(expr_node, source),
        // Remote call (module:fun(...)) is not an intra-module function edge.
        "remote" => None,
        _ => extract_erlang_name(expr_node, source),
    }
}

/// Extract Cowboy-style API endpoint declarations from Erlang AST tuples.
///
/// We look for tuples that contain:
/// - first element: path string (`"/..."`)
/// - second element: handler module atom/name
fn extract_erlang_api_endpoints(
    tree: &Tree,
    source: &str,
) -> Vec<(Vec<String>, String, String)> {
    let mut endpoints = Vec::new();
    let mut seen: HashSet<(String, String)> = HashSet::new();
    let root = tree.root_node();
    walk_tree(root, |node| {
        if node.kind() != "tuple" {
            return;
        }
        let mut cursor = node.walk();
        let exprs: Vec<Node> = node.children_by_field_name("expr", &mut cursor).collect();
        if exprs.len() < 2 {
            return;
        }
        let Some(path_raw) = extract_erlang_string_literal(exprs[0], source) else {
            return;
        };
        let path = normalize_api_path(&path_raw);
        if !path.starts_with('/') {
            return;
        }
        let Some(handler_name) = extract_erlang_name(exprs[1], source) else {
            return;
        };
        let key = (path.clone(), handler_name.clone());
        if seen.insert(key) {
            endpoints.push((vec!["ANY".to_string()], path, handler_name));
        }
    });

    endpoints
}

/// Extract full external HTTP(S) URLs referenced in source code by
/// scanning for string literals that start with "http://" or "https://".
///
/// This generic helper is used by non-Erlang language flows.
fn extract_external_http_urls(source: &str) -> Vec<String> {
    let mut urls = HashSet::new();

    for line in source.lines() {
        let mut rest = line;
        loop {
            let start = match rest.find("http://").or_else(|| rest.find("https://")) {
                Some(i) => i,
                None => break,
            };
            let after = &rest[start..];
            let end = after
                .find(|c: char| c == '"' || c.is_whitespace() || c == '\'' || c == ')')
                .unwrap_or(after.len());
            let url = &after[..end];
            if !url.is_empty() {
                urls.insert(url.to_string());
            }
            rest = &after[end..];
        }
    }

    urls.into_iter().collect()
}

/// Extract HTTP(S) URLs from Erlang AST string literal nodes.
fn extract_external_http_urls_from_tree(tree: &Tree, source: &str) -> Vec<String> {
    let mut urls = HashSet::new();
    let root = tree.root_node();
    walk_tree(root, |node| {
        let Some(s) = extract_erlang_string_literal(node, source) else {
            return;
        };
        if s.starts_with("http://") || s.starts_with("https://") {
            urls.insert(s);
        }
    });

    urls.into_iter().collect()
}

/// Scan `[span_start, span_end)` for `http://` / `https://` tokens, same delimiters as
/// [`extract_external_http_urls`] but bounded to an AST literal span (excludes comments).
fn scan_http_urls_in_span(source: &str, span_start: usize, span_end: usize) -> Vec<(String, usize, usize)> {
    let mut out = Vec::new();
    if span_start >= span_end || span_end > source.len() {
        return out;
    }
    let mut rest_start = span_start;
    while rest_start < span_end {
        let Some(slice) = source.get(rest_start..span_end) else {
            break;
        };
        let rel = match slice.find("http://").or_else(|| slice.find("https://")) {
            Some(i) => i,
            None => break,
        };
        let abs_start = rest_start + rel;
        let Some(after) = source.get(abs_start..span_end) else {
            break;
        };
        let end_rel = after
            .find(|c: char| c == '"' || c.is_whitespace() || c == '\'' || c == ')')
            .unwrap_or(after.len());
        let url = after[..end_rel].trim();
        if !url.is_empty() {
            out.push((url.to_string(), abs_start, abs_start + end_rel));
        }
        rest_start = abs_start + end_rel.max(1);
    }
    out
}

/// HTTP(S) URLs from C# string literals and interpolated string fragments only (not comments).
fn extract_csharp_external_http_urls_with_spans(tree: &Tree, source: &str) -> Vec<(String, usize, usize)> {
    let mut seen: HashSet<(String, usize, usize)> = HashSet::new();
    let root = tree.root_node();
    walk_tree(root, |node| {
        let kind = node.kind();
        if !matches!(
            kind,
            "string_literal"
                | "verbatim_string_literal"
                | "interpolated_string_text"
                | "interpolated_verbatim_string_text"
        ) {
            return;
        }
        let start = node.start_byte() as usize;
        let end = node.end_byte() as usize;
        for triple in scan_http_urls_in_span(source, start, end) {
            seen.insert(triple);
        }
    });
    seen.into_iter().collect()
}

/// `(function_fqn, body_start_byte, body_end_byte)` for methods, instance/static constructors, and
/// property accessors. FQN rules match [`extract_csharp_symbols`] / [`extract_csharp_calls`] (CRM-3587).
fn csharp_method_body_spans(tree: &Tree, source: &str, namespace: Option<&str>) -> Vec<(String, usize, usize)> {
    let mut out = Vec::new();
    let root = tree.root_node();
    walk_tree(root, |node| {
        match node.kind() {
            "method_declaration" => {
                let Some(body) = node.child_by_field_name("body") else {
                    return;
                };
                let Some(method_name) = csharp_method_simple_name(node, source) else {
                    return;
                };
                let class_fqn = csharp_enclosing_type_fqn(node, source, namespace);
                let effective_ns = csharp_enclosing_namespace_prefix(node, source)
                    .or_else(|| namespace.map(|s| s.to_string()));
                let fqn = match class_fqn {
                    Some(cf) => format!("{cf}.{method_name}"),
                    None => effective_ns
                        .as_ref()
                        .map(|ns| format!("{ns}.{method_name}"))
                        .unwrap_or(method_name),
                };
                let lo = body.start_byte() as usize;
                let hi = body.end_byte() as usize;
                out.push((fqn, lo, hi));
            }
            "constructor_declaration" => {
                let Some(cf) = csharp_enclosing_type_fqn(node, source, namespace) else {
                    return;
                };
                let (_, fqn) = csharp_constructor_symbol_fqn(node, &cf, source);
                let Some(body) = csharp_block_body(node) else {
                    return;
                };
                let lo = body.start_byte() as usize;
                let hi = body.end_byte() as usize;
                out.push((fqn, lo, hi));
            }
            "accessor_declaration" => {
                let Some(cf) = csharp_enclosing_type_fqn(node, source, namespace) else {
                    return;
                };
                let Some(prop_name) = csharp_property_name_for_accessor(node, source) else {
                    return;
                };
                let prefix = csharp_accessor_kind_prefix(node, source);
                let fqn = format!("{cf}.{}_{}", prefix, prop_name);
                let Some(body) = csharp_block_body(node) else {
                    return;
                };
                let lo = body.start_byte() as usize;
                let hi = body.end_byte() as usize;
                out.push((fqn, lo, hi));
            }
            _ => {}
        }
    });
    out
}

/// Extract Erlang module names from AST remote calls (`module:fun(...)`).
fn extract_erlang_called_modules_from_tree(tree: &Tree, source: &str) -> HashSet<String> {
    let mut modules = HashSet::new();
    let root = tree.root_node();
    walk_tree(root, |node| {
        if node.kind() != "remote" {
            return;
        }
        let Some(remote_module) = node.child_by_field_name("module") else {
            return;
        };
        let Some(module_expr) = remote_module.child_by_field_name("module") else {
            return;
        };
        if let Some(name) = extract_erlang_name(module_expr, source) {
            modules.insert(name);
        }
    });

    modules
}

/// Split a URL string into (protocol, host, path) if possible.
///
/// - `protocol`: e.g. "http" or "https".
/// - `host`: e.g. "qproxy.latam.redbus.in" or "publisher1.ias.redbus.in:8002".
/// - `path`: everything after the host, starting with '/', query, etc.
fn split_url_protocol_host_and_path(url: &str) -> (Option<String>, String, String) {
    if let Some(idx) = url.find("://") {
        let proto = &url[..idx];
        let rest = &url[idx + 3..];

        // Host is everything up to the first '/' or '?'.
        // We intentionally DO NOT split on ':' so that ports remain part of the host,
        // e.g. "publisher1.ias.redbus.in:8002" stays together.
        let host_end = rest
            .find(|c: char| c == '/' || c == '?')
            .unwrap_or(rest.len());

        let host = &rest[..host_end];
        let path = if host_end < rest.len() {
            &rest[host_end..]
        } else {
            "/"
        };

        (
            Some(proto.to_string()),
            host.to_string(),
            path.to_string(),
        )
    } else {
        (None, url.to_string(), "/".to_string())
    }
}

/// Normalize an API path so that semantically equivalent paths have the same
/// representation across ApiEndpoint and ExternalApi nodes.
///
/// Normalizations applied:
/// - Trim whitespace.
/// - If a full URL is given, strip scheme + host, keep only path+query.
/// - Drop query string and fragment (everything after '?' or '#').
/// - Ensure a single leading '/'.
/// - Drop trailing '/' (except for root).
fn normalize_api_path(raw: &str) -> String {
    let mut p = raw.trim().to_string();

    // If we accidentally receive a full URL, keep only the path+query part.
    if let Some(idx) = p.find("://") {
        let after = &p[idx + 3..];
        if let Some(slash) = after.find('/') {
            p = after[slash..].to_string();
        } else {
            // No path segment; treat as root.
            return "/".to_string();
        }
    }

    // Strip query string and fragment.
    if let Some(idx) = p.find(|c: char| c == '?' || c == '#') {
        p.truncate(idx);
    }

    // Ensure leading slash.
    if !p.starts_with('/') {
        p.insert(0, '/');
    }

    // Drop trailing slash except for root.
    if p.len() > 1 && p.ends_with('/') {
        p.pop();
    }

    p
}

fn extract_erlang_string_literal(node: Node, source: &str) -> Option<String> {
    if node.kind() != "string" {
        return None;
    }
    let raw = node_text(node, source)?.trim();
    // Regular string literal: "value"
    if raw.starts_with('"') && raw.ends_with('"') && raw.len() >= 2 {
        return Some(raw[1..raw.len() - 1].to_string());
    }
    // Fallback for sigil strings and other forms: if quoted section exists,
    // capture inner value between first/last quote.
    let first = raw.find('"')?;
    let last = raw.rfind('"')?;
    if last > first {
        return Some(raw[first + 1..last].to_string());
    }
    None
}

/// Guess a `.erl` file path for a given Erlang module name, assuming a
/// one-module-per-file convention in the same directory as `current_path`.
fn guess_erlang_file_path_from_module(current_path: &str, module_name: &str) -> String {
    let base = Path::new(current_path)
        .parent()
        .map(|p| p.to_path_buf())
        .unwrap_or_else(|| Path::new(".").to_path_buf());
    path_str_slash(&base.join(format!("{module}.erl", module = module_name)))
}

fn node_byte_span(node: Node) -> (usize, usize) {
    (
        node.start_byte() as usize,
        node.end_byte() as usize,
    )
}

fn insert_widest_span(map: &mut HashMap<String, (usize, usize)>, key: String, span: (usize, usize)) {
    map.entry(key)
        .and_modify(|existing| {
            existing.0 = existing.0.min(span.0);
            existing.1 = existing.1.max(span.1);
        })
        .or_insert(span);
}

fn extract_java_class_spans(tree: &Tree, source: &str, package: Option<&str>) -> HashMap<String, (usize, usize)> {
    let mut out = HashMap::new();
    walk_tree(tree.root_node(), |node| {
        if node.kind() != "class_declaration" && node.kind() != "interface_declaration" {
            return;
        }
        let Some(name) = identifier_text_from_children(node, source) else {
            return;
        };
        let fqn = package
            .map(|pkg| format!("{pkg}.{name}"))
            .unwrap_or(name);
        insert_widest_span(&mut out, fqn, node_byte_span(node));
    });
    out
}

fn extract_java_method_body_spans(
    tree: &Tree,
    source: &str,
    package: Option<&str>,
) -> HashMap<String, (usize, usize)> {
    let mut out = HashMap::new();
    walk_tree(tree.root_node(), |node| {
        if node.kind() != "method_declaration" {
            return;
        }
        let Some(method_name) = identifier_text_from_children(node, source) else {
            return;
        };
        let mut parent = node.parent();
        let mut class_fqn: Option<String> = None;
        while let Some(p) = parent {
            let pk = p.kind();
            if pk == "class_declaration" || pk == "interface_declaration" {
                if let Some(class_name) = identifier_text_from_children(p, source) {
                    class_fqn = Some(
                        package
                            .map(|pkg| format!("{pkg}.{class_name}"))
                            .unwrap_or(class_name),
                    );
                }
                break;
            }
            parent = p.parent();
        }
        let fqn = if let Some(ref cls) = class_fqn {
            format!("{cls}.{method_name}")
        } else if let Some(pkg) = package {
            format!("{pkg}.{method_name}")
        } else {
            method_name.clone()
        };
        let span = node
            .child_by_field_name("body")
            .map(node_byte_span)
            .unwrap_or_else(|| node_byte_span(node));
        insert_widest_span(&mut out, fqn, span);
    });
    out
}

fn extract_csharp_class_spans(tree: &Tree, source: &str) -> HashMap<String, (usize, usize)> {
    let mut out = HashMap::new();
    let namespace = extract_csharp_namespace(tree, source);
    walk_tree(tree.root_node(), |node| {
        match node.kind() {
            "class_declaration"
            | "interface_declaration"
            | "struct_declaration"
            | "enum_declaration"
            | "record_declaration"
            | "record_struct_declaration" => {
                if let Some(fqn) = csharp_fqn_for_type_declaration(node, source, namespace.as_deref()) {
                    insert_widest_span(&mut out, fqn, node_byte_span(node));
                }
            }
            _ => {}
        }
    });
    out
}

fn extract_csharp_property_spans(tree: &Tree, source: &str) -> HashMap<String, (usize, usize)> {
    let mut out = HashMap::new();
    let namespace = extract_csharp_namespace(tree, source);
    walk_tree(tree.root_node(), |node| {
        if node.kind() != "property_declaration" {
            return;
        }
        let Some(class_fqn) = csharp_enclosing_type_fqn(node, source, namespace.as_deref()) else {
            return;
        };
        let Some(prop_name_node) = node.child_by_field_name("name") else {
            return;
        };
        let Some(prop_name) = csharp_node_text(prop_name_node, source).filter(|s| !s.is_empty()) else {
            return;
        };
        let fqn = format!("{class_fqn}.{prop_name}");
        insert_widest_span(&mut out, fqn, node_byte_span(node));
    });
    out
}

fn extract_csharp_method_body_spans_map(
    tree: &Tree,
    source: &str,
    namespace: Option<&str>,
) -> HashMap<String, (usize, usize)> {
    csharp_method_body_spans(tree, source, namespace)
        .into_iter()
        .map(|(fqn, lo, hi)| (fqn, (lo, hi)))
        .collect()
}

fn extract_erlang_function_spans(
    module_name: &str,
    tree: &Tree,
    source: &str,
) -> HashMap<String, (usize, usize)> {
    let mut out = HashMap::new();
    walk_tree(tree.root_node(), |node| {
        if node.kind() != "function_clause" || !is_top_level_erlang_function_clause(node) {
            return;
        }
        let Some(name_node) = node.child_by_field_name("name") else {
            return;
        };
        let Some(fun_name) = extract_erlang_name(name_node, source) else {
            return;
        };
        let Some(args_node) = node.child_by_field_name("args") else {
            return;
        };
        let arity = args_node.named_child_count() as u32;
        let fqn = format!("{module_name}:{fun_name}/{arity}");
        insert_widest_span(&mut out, fqn, node_byte_span(node));
    });
    out
}

fn extract_go_class_spans(
    tree: &Tree,
    source: &str,
    package: Option<&str>,
) -> HashMap<String, (usize, usize)> {
    let mut out = HashMap::new();
    walk_tree(tree.root_node(), |node| {
        if node.kind() != "type_declaration" {
            return;
        }
        let mut i = 0usize;
        while let Some(child) = node.child(i) {
            i += 1;
            if child.kind() != "type_spec" {
                continue;
            }
            let Some(type_n) = child.child_by_field_name("type") else {
                continue;
            };
            if type_n.kind() != "struct_type" && type_n.kind() != "interface_type" {
                continue;
            }
            let Some(name_node) = child.child_by_field_name("name") else {
                continue;
            };
            let start = name_node.start_byte() as usize;
            let end = (name_node.end_byte() as usize).min(source.len());
            if start >= end {
                continue;
            }
            let name = source[start..end].to_string();
            let fqn = package
                .map(|pkg| format!("{pkg}.{name}"))
                .unwrap_or(name);
            insert_widest_span(&mut out, fqn, node_byte_span(child));
        }
    });
    out
}

fn extract_go_function_body_spans(
    tree: &Tree,
    source: &str,
    package: Option<&str>,
) -> HashMap<String, (usize, usize)> {
    let mut out = HashMap::new();
    walk_tree(tree.root_node(), |node| {
        let kind = node.kind();
        if kind != "function_declaration" && kind != "method_declaration" {
            return;
        }
        let fqn = match kind {
            "function_declaration" => go_decl_fqn_from_function_declaration(node, source, package),
            "method_declaration" => go_decl_fqn_from_method_declaration(node, source, package),
            _ => None,
        };
        let Some(fqn) = fqn else {
            return;
        };
        let span = node
            .child_by_field_name("body")
            .map(node_byte_span)
            .unwrap_or_else(|| node_byte_span(node));
        insert_widest_span(&mut out, fqn, span);
    });
    out
}

fn extract_non_java_function_body_spans(
    file: &ParsedFile,
    source: &str,
    file_path: &str,
) -> HashMap<String, (usize, usize)> {
    let mut out = HashMap::new();
    match file.language {
        LanguageId::Python => {
            walk_tree(file.tree.root_node(), |node| {
                if node.kind() != "function_definition" || python_node_inside_class(node) {
                    return;
                }
                let Some(logical) = python_function_logical_name(node, source) else {
                    return;
                };
                let fqn = non_java_file_scoped_fqn(file_path, &logical);
                let span = node
                    .child_by_field_name("body")
                    .map(node_byte_span)
                    .unwrap_or_else(|| node_byte_span(node));
                insert_widest_span(&mut out, fqn, span);
            });
        }
        LanguageId::JavaScript | LanguageId::TypeScript | LanguageId::Tsx => {
            walk_tree(file.tree.root_node(), |node| {
                if node.kind() != "function_declaration" {
                    return;
                }
                let Some(name) = js_ts_function_name(node, source) else {
                    return;
                };
                let fqn = non_java_file_scoped_fqn(file_path, &name);
                let span = node
                    .child_by_field_name("body")
                    .map(node_byte_span)
                    .unwrap_or_else(|| node_byte_span(node));
                insert_widest_span(&mut out, fqn, span);
            });
        }
        LanguageId::Rust => {
            walk_tree(file.tree.root_node(), |node| {
                if node.kind() != "function_item" || rust_inside_impl(node) {
                    return;
                }
                let Some(logical) = rust_function_logical_name(node, source) else {
                    return;
                };
                let fqn = non_java_file_scoped_fqn(file_path, &logical);
                let span = node
                    .child_by_field_name("body")
                    .map(node_byte_span)
                    .unwrap_or_else(|| node_byte_span(node));
                insert_widest_span(&mut out, fqn, span);
            });
        }
        _ => {}
    }
    out
}

fn js_ts_function_name(node: Node, source: &str) -> Option<String> {
    node.child_by_field_name("name")
        .and_then(|n| node_text_slice(n, source))
        .map(|s| s.trim().to_string())
        .filter(|s| !s.is_empty())
}

fn rust_function_name(node: Node, source: &str) -> Option<String> {
    node.child_by_field_name("name")
        .and_then(|n| node_text_slice(n, source))
        .map(|s| s.trim().to_string())
        .filter(|s| !s.is_empty())
}

async fn code_bytes_for_span(
    compressor: Option<&CompressorClient>,
    source: &str,
    span: Option<(usize, usize)>,
    language: LanguageId,
) -> Option<Vec<u8>> {
    let client = compressor?;
    compress_snippet(source, span, language, client).await
}

/// Walk a Tree-Sitter tree depth-first, applying `f` to every node.
fn walk_tree(root: Node, mut f: impl FnMut(Node)) {
    let mut stack = vec![root];
    while let Some(node) = stack.pop() {
        f(node);
        let child_count = node.child_count();
        for i in (0..child_count).rev() {
            if let Some(child) = node.child(i) {
                stack.push(child);
            }
        }
    }
}

/// Like [`walk_tree`], but does not descend into `local_function_statement` subtrees
/// (so nested locals are not attributed to the enclosing method for type extraction).
fn walk_tree_skip_local_functions(root: Node, mut f: impl FnMut(Node)) {
    let mut stack = vec![root];
    while let Some(node) = stack.pop() {
        f(node);
        if node.kind() == "local_function_statement" {
            continue;
        }
        let child_count = node.child_count();
        for i in (0..child_count).rev() {
            if let Some(child) = node.child(i) {
                stack.push(child);
            }
        }
    }
}

/// Get the first identifier-like child text from a node.
fn identifier_text_from_children(node: Node, source: &str) -> Option<String> {
    let child_count = node.child_count();
    for i in 0..child_count {
        if let Some(child) = node.child(i) {
            let kind = child.kind();
            if kind == "identifier" || kind == "name" {
                let start = child.start_byte() as usize;
                let end = child.end_byte() as usize;
                if end <= source.len() && start < end {
                    return Some(source[start..end].to_string());
                }
            }
        }
    }
    None
}

/// Extract Java classes and methods from the AST.
fn extract_java_symbols(
    tree: &Tree,
    source: &str,
    package: Option<&str>,
) -> (Vec<ClassSymbol>, Vec<FunctionSymbol>) {
    let mut classes: Vec<ClassSymbol> = Vec::new();
    let mut methods: Vec<FunctionSymbol> = Vec::new();
    let mut seen_class_fqns: HashSet<String> = HashSet::new();

    let root = tree.root_node();
    walk_tree(root, |node| {
        let kind = node.kind();
        match kind {
            "class_declaration" | "interface_declaration" => {
                if let Some(name) = identifier_text_from_children(node, source) {
                    let fqn = if let Some(pkg) = package {
                        format!("{pkg}.{name}")
                    } else {
                        name.clone()
                    };
                    if seen_class_fqns.insert(fqn.clone()) {
                        classes.push(ClassSymbol {
                            name,
                            fqn,
                            kind: None,
                        });
                    }
                }
            }
            "method_declaration" => {
                if let Some(method_name) = identifier_text_from_children(node, source) {
                    // Find the nearest enclosing class or interface to build the FQN.
                    let mut parent = node.parent();
                    let mut class_fqn: Option<String> = None;
                    while let Some(p) = parent {
                        let pk = p.kind();
                        if pk == "class_declaration" || pk == "interface_declaration" {
                            if let Some(class_name) = identifier_text_from_children(p, source) {
                                let full = if let Some(pkg) = package {
                                    format!("{pkg}.{class_name}")
                                } else {
                                    class_name
                                };
                                class_fqn = Some(full);
                            }
                            break;
                        }
                        parent = p.parent();
                    }

                    let fqn = if let Some(ref cls) = class_fqn {
                        format!("{cls}.{}", method_name)
                    } else if let Some(pkg) = package {
                        format!("{pkg}.{}", method_name)
                    } else {
                        method_name.clone()
                    };

                    let (return_type, param_types, param_count) =
                        extract_java_method_signature_types(node, source);

                    methods.push(FunctionSymbol {
                        name: method_name,
                        fqn,
                        class_fqn,
                        return_type,
                        param_types,
                        param_count,
                        modifiers: Vec::new(),
                        is_pointer_receiver: None,
                    });
                }
            }
            _ => {}
        }
    });

    (classes, methods)
}

/// Java parse warnings: Tree-Sitter `ERROR` / missing nodes (CRM-3647).
fn extract_java_parse_warnings(tree: &Tree, source: &str) -> Vec<(usize, usize, String)> {
    let mut out = Vec::new();
    let root = tree.root_node();
    walk_tree(root, |node| {
        if node.kind() == "ERROR" || node.is_missing() {
            let pos = node.start_position();
            let s = node.start_byte() as usize;
            let e = (node.end_byte() as usize).min(source.len());
            let snippet = if s < e {
                source[s..e]
                    .chars()
                    .take(120)
                    .collect::<String>()
                    .replace('\n', " ")
            } else {
                String::new()
            };
            out.push((pos.row + 1, pos.column + 1, snippet));
        }
    });
    out
}

/// Strip outer generic arguments for simple type display, e.g. `ResponseEntity<List<X>>` → `ResponseEntity`.
fn java_simple_type_name(type_text: &str) -> String {
    let t = type_text.trim();
    t.split('<')
        .next()
        .unwrap_or(t)
        .trim()
        .split_whitespace()
        .last()
        .unwrap_or(t)
        .trim()
        .to_string()
}

/// Text of a Java `type` AST node (method return / parameter type).
fn java_type_node_display(node: Node, source: &str) -> Option<String> {
    let s = node.start_byte() as usize;
    let e = (node.end_byte() as usize).min(source.len());
    if s >= e {
        return None;
    }
    Some(source[s..e].trim().to_string())
}

/// Return type (simple name), parameter simple types, and count for a `method_declaration`.
fn extract_java_method_signature_types(
    method: Node,
    source: &str,
) -> (Option<String>, Vec<String>, usize) {
    let return_type = method
        .child_by_field_name("type")
        .and_then(|n| java_type_node_display(n, source))
        .map(|full| java_simple_type_name(&full));

    let mut param_types: Vec<String> = Vec::new();
    if let Some(params) = method.child_by_field_name("parameters") {
        let mut i = 0usize;
        while let Some(child) = params.child(i) {
            i += 1;
            if child.kind() == "formal_parameter" || child.kind() == "spread_parameter" {
                if let Some(tn) = child.child_by_field_name("type") {
                    if let Some(full) = java_type_node_display(tn, source) {
                        param_types.push(java_simple_type_name(&full));
                    }
                }
            }
        }
    }

    let param_count = param_types.len();
    (return_type, param_types, param_count)
}

/// `(child_class_fqn, parent_or_interface_fqn)` for extends/implements (CRM-3649).
fn extract_java_inheritance_edges(
    tree: &Tree,
    source: &str,
    package: Option<&str>,
) -> Vec<(String, String)> {
    let mut edges = Vec::new();
    let import_map = build_internal_import_map(source);
    let root = tree.root_node();

    walk_tree(root, |node| {
        if node.kind() != "class_declaration" {
            return;
        }
        let Some(class_name) = identifier_text_from_children(node, source) else {
            return;
        };
        let child_fqn = match package {
            Some(pkg) => format!("{pkg}.{class_name}"),
            None => class_name,
        };

        let resolve = |type_node: Node| {
            java_resolve_type_fqn(type_node, source, package, &import_map)
        };

        if let Some(super_c) = node.child_by_field_name("superclass") {
            if let Some(p) = resolve(super_c) {
                edges.push((child_fqn.clone(), p));
            }
        }
        if let Some(ifs) = node.child_by_field_name("interfaces") {
            let mut i = 0usize;
            while let Some(ch) = ifs.child(i) {
                i += 1;
                if ch.kind() == "type_list" {
                    let mut j = 0usize;
                    while let Some(t) = ch.child(j) {
                        j += 1;
                        if let Some(p) = resolve(t) {
                            edges.push((child_fqn.clone(), p));
                        }
                    }
                }
            }
        }
    });

    edges
}

fn java_resolve_type_fqn(
    type_node: Node,
    source: &str,
    package: Option<&str>,
    import_map: &HashMap<String, String>,
) -> Option<String> {
    let s = type_node.start_byte() as usize;
    let e = (type_node.end_byte() as usize).min(source.len());
    if s < e && type_node.kind() == "scoped_type_identifier" {
        let text = source[s..e].trim();
        if text.contains('.') && !text.is_empty() {
            return Some(text.to_string());
        }
    }

    let simple: String = match type_node.kind() {
        "integral_type" | "floating_point_type" | "boolean_type" | "void_type" => {
            if s >= e {
                return None;
            }
            source[s..e].trim().to_string()
        }
        _ => type_node
            .child_by_field_name("name")
            .and_then(|n| {
                let s = n.start_byte() as usize;
                let e = (n.end_byte() as usize).min(source.len());
                if s < e {
                    Some(source[s..e].to_string())
                } else {
                    None
                }
            })
            .or_else(|| {
                let mut found: Option<String> = None;
                walk_tree(type_node, |n| {
                    if found.is_some() {
                        return;
                    }
                    if n.kind() == "type_identifier" {
                        let s = n.start_byte() as usize;
                        let e = (n.end_byte() as usize).min(source.len());
                        if s < e {
                            found = Some(source[s..e].to_string());
                        }
                    }
                });
                found
            })?,
    };

    if is_java_primitive_or_builtin(&simple) {
        return None;
    }
    Some(
        import_map
            .get(&simple)
            .cloned()
            .unwrap_or_else(|| match package {
                Some(pkg) => format!("{pkg}.{simple}"),
                None => simple,
            }),
    )
}

/// `(class_fqn, annotation simple names)` for classes (CRM-3648).
fn extract_java_class_annotations(
    tree: &Tree,
    source: &str,
    package: Option<&str>,
) -> Vec<(String, Vec<String>)> {
    let mut out = Vec::new();
    let root = tree.root_node();
    walk_tree(root, |node| {
        if node.kind() != "class_declaration" && node.kind() != "interface_declaration" {
            return;
        }
        let Some(class_name) = identifier_text_from_children(node, source) else {
            return;
        };
        let class_fqn = match package {
            Some(pkg) => format!("{pkg}.{class_name}"),
            None => class_name,
        };
        let anns = java_modifiers_annotations(node, source);
        if !anns.is_empty() {
            out.push((class_fqn, anns));
        }
    });
    out
}

/// `(method_fqn, annotation simple names)` (CRM-3648).
fn extract_java_method_annotations(
    tree: &Tree,
    source: &str,
    package: Option<&str>,
) -> Vec<(String, Vec<String>)> {
    let mut out = Vec::new();
    let root = tree.root_node();
    walk_tree(root, |node| {
        if node.kind() != "method_declaration" {
            return;
        }
        let Some(method_name) = identifier_text_from_children(node, source) else {
            return;
        };
        let mut parent = node.parent();
        let mut class_fqn: Option<String> = None;
        while let Some(p) = parent {
            let pk = p.kind();
            if pk == "class_declaration" || pk == "interface_declaration" {
                if let Some(class_name) = identifier_text_from_children(p, source) {
                    class_fqn = Some(match package {
                        Some(pkg) => format!("{pkg}.{class_name}"),
                        None => class_name,
                    });
                }
                break;
            }
            parent = p.parent();
        }
        let fqn = match &class_fqn {
            Some(cls) => format!("{cls}.{method_name}"),
            None => match package {
                Some(pkg) => format!("{pkg}.{method_name}"),
                None => method_name.clone(),
            },
        };
        let anns = java_modifiers_annotations(node, source);
        if !anns.is_empty() {
            out.push((fqn, anns));
        }
    });
    out
}

fn java_modifiers_annotations(node: Node, source: &str) -> Vec<String> {
    let mut names = Vec::new();
    let mut i = 0usize;
    while let Some(ch) = node.child(i) {
        i += 1;
        if ch.kind() == "modifiers" {
            let mut j = 0usize;
            while let Some(m) = ch.child(j) {
                j += 1;
                if m.kind() == "marker_annotation" || m.kind() == "annotation" {
                    if let Some(n) = m.named_child(0) {
                        if n.kind() == "identifier" || n.kind() == "scoped_identifier" {
                            let s = n.start_byte() as usize;
                            let e = (n.end_byte() as usize).min(source.len());
                            if s < e {
                                let raw = source[s..e].to_string();
                                let simple = raw.rsplit('.').next().unwrap_or(&raw).to_string();
                                names.push(simple);
                            }
                        }
                    }
                }
            }
        }
    }
    names
}

fn java_type_has_autowired(type_node: Node, source: &str) -> bool {
    let mut found = false;
    walk_tree(type_node, |n| {
        if n.kind() == "modifiers" {
            let mut j = 0usize;
            while let Some(m) = n.child(j) {
                j += 1;
                if m.kind() == "marker_annotation" || m.kind() == "annotation" {
                    if let Some(id) = m.named_child(0) {
                        let s = id.start_byte() as usize;
                        let e = (id.end_byte() as usize).min(source.len());
                        if s < e {
                            let raw = &source[s..e];
                            if raw == "Autowired" || raw.ends_with(".Autowired") {
                                found = true;
                            }
                        }
                    }
                }
            }
        }
    });
    found
}

/// `(class_fqn, injected_type_fqn)` for constructor + `@Autowired` fields (CRM-3650).
fn extract_java_injected_dependencies(
    tree: &Tree,
    source: &str,
    package: Option<&str>,
) -> Vec<(String, String)> {
    let mut out = Vec::new();
    let import_map = build_internal_import_map(source);
    let root = tree.root_node();

    walk_tree(root, |node| {
        if node.kind() != "class_declaration" {
            return;
        }
        let Some(class_name) = identifier_text_from_children(node, source) else {
            return;
        };
        let class_fqn = match package {
            Some(pkg) => format!("{pkg}.{class_name}"),
            None => class_name,
        };

        let mut i = 0usize;
        while let Some(body) = node.child(i) {
            i += 1;
            if body.kind() != "class_body" {
                continue;
            }
            let mut j = 0usize;
            while let Some(member) = body.child(j) {
                j += 1;
                match member.kind() {
                    "constructor_declaration" => {
                        if let Some(params) = member.child_by_field_name("parameters") {
                            let mut k = 0usize;
                            while let Some(p) = params.child(k) {
                                k += 1;
                                if p.kind() == "formal_parameter" {
                                    if let Some(tn) = p.child_by_field_name("type") {
                                        if let Some(fqn) =
                                            java_resolve_type_fqn(tn, source, package, &import_map)
                                        {
                                            out.push((class_fqn.clone(), fqn));
                                        }
                                    }
                                }
                            }
                        }
                    }
                    "field_declaration" => {
                        if !java_type_has_autowired(member, source) {
                            continue;
                        }
                        let type_node = member
                            .child_by_field_name("type")
                            .or_else(|| {
                                let mut k = 0usize;
                                while let Some(ch) = member.child(k) {
                                    if matches!(
                                        ch.kind(),
                                        "type_identifier"
                                            | "generic_type"
                                            | "array_type"
                                            | "integral_type"
                                            | "floating_point_type"
                                            | "boolean_type"
                                            | "void_type"
                                    ) {
                                        return Some(ch);
                                    }
                                    k += 1;
                                }
                                None
                            });
                        if let Some(tn) = type_node {
                            if let Some(fqn) = java_resolve_type_fqn(tn, source, package, &import_map)
                            {
                                out.push((class_fqn.clone(), fqn));
                            }
                        }
                    }
                    _ => {}
                }
            }
        }
    });

    out
}

/// Line-based namespace fallback when the AST has no `namespace` node (CRM-3586).
fn extract_csharp_namespace_line_fallback(source: &str) -> Option<String> {
    for line in source.lines() {
        let trimmed = line.trim();
        if trimmed.starts_with("namespace ") {
            let rest = &trimmed["namespace ".len()..];
            let ns = rest
                .split(|c: char| c == '{' || c == ';' || c.is_whitespace())
                .next()?
                .trim();
            if !ns.is_empty() {
                return Some(ns.to_string());
            }
        }
    }
    None
}

/// First file-scoped or top-level block namespace from the compilation unit (CRM-3586).
fn extract_csharp_namespace_from_ast(tree: &Tree, source: &str) -> Option<String> {
    let root = tree.root_node();
    for i in 0..root.named_child_count() {
        let c = root.named_child(i)?;
        if c.kind() == "file_scoped_namespace_declaration" {
            return csharp_namespace_declaration_name(c, source);
        }
    }
    for i in 0..root.named_child_count() {
        let c = root.named_child(i)?;
        if c.kind() == "namespace_declaration" {
            return csharp_namespace_declaration_name(c, source);
        }
    }
    None
}

/// `namespace X` / `namespace X.Y` / file-scoped: full name text from the `name` field.
fn csharp_namespace_declaration_name(decl: Node, source: &str) -> Option<String> {
    if !matches!(
        decl.kind(),
        "namespace_declaration" | "file_scoped_namespace_declaration"
    ) {
        return None;
    }
    decl.child_by_field_name("name")
        .and_then(|n| csharp_node_text(n, source))
        .filter(|s| !s.is_empty())
}

/// Walk parents from `node` and build `Outer.Inner` namespace prefix (CRM-3586).
fn csharp_enclosing_namespace_prefix(node: Node, source: &str) -> Option<String> {
    let mut segments: Vec<String> = Vec::new();
    let mut cur = node.parent();
    while let Some(p) = cur {
        if matches!(
            p.kind(),
            "namespace_declaration" | "file_scoped_namespace_declaration"
        ) {
            if let Some(name) = csharp_namespace_declaration_name(p, source) {
                segments.push(name);
            }
        }
        cur = p.parent();
    }
    segments.reverse();
    if segments.is_empty() {
        None
    } else {
        Some(segments.join("."))
    }
}

/// All distinct namespace prefixes that enclose any type declaration in the file (for batch index).
fn collect_csharp_file_namespace_strings(tree: &Tree, source: &str) -> Vec<String> {
    let mut seen: HashSet<String> = HashSet::new();
    let root = tree.root_node();
    walk_tree(root, |n| {
        if matches!(
            n.kind(),
            "class_declaration"
                | "interface_declaration"
                | "struct_declaration"
                | "enum_declaration"
                | "record_declaration"
                | "record_struct_declaration"
        ) {
            if let Some(p) = csharp_enclosing_namespace_prefix(n, source) {
                seen.insert(p);
            }
        }
    });
    if seen.is_empty() {
        if let Some(p) = extract_csharp_namespace_from_ast(tree, source) {
            seen.insert(p);
        } else if let Some(p) = extract_csharp_namespace_line_fallback(source) {
            seen.insert(p);
        }
    }
    let mut v: Vec<String> = seen.into_iter().collect();
    v.sort();
    v
}

/// Primary namespace for a file: AST first, then line fallback (CRM-3586).
fn extract_csharp_namespace(tree: &Tree, source: &str) -> Option<String> {
    extract_csharp_namespace_from_ast(tree, source).or_else(|| extract_csharp_namespace_line_fallback(source))
}

/// Parsed `using` directive (namespace import, alias, or static).
#[derive(Debug, Clone, PartialEq, Eq)]
enum CSharpUsingKind {
    /// `using Ns.A.B;` or `global using Ns.A.B;`
    Namespace(String),
    /// `using static X.Y.Z;` — excluded from file deps and namespace import list.
    Static(String),
    /// `using Alias = Target;`
    Alias { alias: String, target: String },
}

/// Namespace imports suitable for `DEPENDS_ON_FILE` and type resolution (non-system only).
#[derive(Debug, Clone, Default)]
struct CSharpUsingSummary {
    namespace_imports: Vec<String>,
    alias_map: HashMap<String, String>,
}

fn normalize_csharp_global_prefix(s: &str) -> String {
    s.replace("global::", "").trim().to_string()
}

/// True if this namespace should not create `DEPENDS_ON_FILE` edges (BCL / Microsoft).
fn is_csharp_system_or_microsoft_namespace(ns: &str) -> bool {
    let ns = ns.trim();
    let ns = ns.strip_prefix("global::").unwrap_or(ns).trim();
    match ns.split('.').next() {
        Some("System") | Some("Microsoft") => true,
        _ => false,
    }
}

/// Parse a `using_directive` AST node into a structured kind.
fn parse_csharp_using_directive(node: Node, source: &str) -> Option<CSharpUsingKind> {
    let start = node.start_byte() as usize;
    let end = node.end_byte() as usize;
    let raw = source.get(start..end)?.trim();
    let mut body = raw.strip_suffix(';')?.trim();

    if let Some(rest) = body.strip_prefix("global") {
        if rest.starts_with(char::is_whitespace) {
            body = rest.trim_start();
        }
    }

    body = body.strip_prefix("using")?.trim();

    if let Some(rest) = body.strip_prefix("static") {
        if rest.starts_with(char::is_whitespace) {
            let target = normalize_csharp_global_prefix(rest.trim_start());
            return if target.is_empty() {
                None
            } else {
                Some(CSharpUsingKind::Static(target))
            };
        }
    }

    if let Some(eq_pos) = body.find('=') {
        let left = body[..eq_pos].trim();
        let right = body[eq_pos + 1..].trim();
        if !left.is_empty()
            && !right.is_empty()
            && left.chars().all(|c| c.is_alphanumeric() || c == '_')
        {
            return Some(CSharpUsingKind::Alias {
                alias: left.to_string(),
                target: normalize_csharp_global_prefix(right),
            });
        }
    }

    let ns = normalize_csharp_global_prefix(body);
    if ns.is_empty() {
        None
    } else {
        Some(CSharpUsingKind::Namespace(ns))
    }
}

/// Walk the tree for `using_directive` nodes (not `using_statement`).
fn extract_csharp_using_summary(tree: &Tree, source: &str) -> CSharpUsingSummary {
    let mut namespace_imports: Vec<String> = Vec::new();
    let mut seen_ns: HashSet<String> = HashSet::new();
    let mut alias_map: HashMap<String, String> = HashMap::new();

    walk_tree(tree.root_node(), |node| {
        if node.kind() != "using_directive" {
            return;
        }
        let Some(kind) = parse_csharp_using_directive(node, source) else {
            return;
        };
        match kind {
            CSharpUsingKind::Namespace(ns) => {
                if !is_csharp_system_or_microsoft_namespace(&ns) && seen_ns.insert(ns.clone()) {
                    namespace_imports.push(ns);
                }
            }
            CSharpUsingKind::Static(_) => {}
            CSharpUsingKind::Alias { alias, target } => {
                alias_map.insert(alias, target);
            }
        }
    });

    CSharpUsingSummary {
        namespace_imports,
        alias_map,
    }
}

/// Batch index for C# files in the current scan (namespace → file paths, type resolution).
#[derive(Debug, Default, Clone)]
struct CSharpBatchIndex {
    namespace_to_paths: HashMap<String, Vec<String>>,
    simple_name_to_fqns: HashMap<String, Vec<String>>,
    class_fqns: HashSet<String>,
}

fn build_csharp_batch_index(files: &[ParsedFile], root: &Path) -> CSharpBatchIndex {
    let mut namespace_to_paths: HashMap<String, Vec<String>> = HashMap::new();
    let mut simple_name_to_fqns: HashMap<String, Vec<String>> = HashMap::new();
    let mut class_fqns: HashSet<String> = HashSet::new();

    for file in files {
        if file.language != LanguageId::CSharp {
            continue;
        }
        let path_str = neo4j_path_string(root, &file.path);
        let source = &file.source;
        let tree = &file.tree;
        for ns in collect_csharp_file_namespace_strings(tree, source) {
            namespace_to_paths
                .entry(ns)
                .or_default()
                .push(path_str.clone());
        }
        let (classes, _, _) = extract_csharp_symbols(tree, source);
        for c in classes {
            class_fqns.insert(c.fqn.clone());
            simple_name_to_fqns
                .entry(c.name.clone())
                .or_default()
                .push(c.fqn.clone());
        }
    }

    for v in namespace_to_paths.values_mut() {
        v.sort();
        v.dedup();
    }
    for v in simple_name_to_fqns.values_mut() {
        v.sort();
        v.dedup();
    }

    CSharpBatchIndex {
        namespace_to_paths,
        simple_name_to_fqns,
        class_fqns,
    }
}

/// Namespaces that contribute to type lookup: normal usings plus alias targets that are not a class FQN.
fn csharp_effective_import_namespaces(
    namespace_imports: &[String],
    alias_map: &HashMap<String, String>,
    class_fqns: &HashSet<String>,
) -> Vec<String> {
    let mut out: Vec<String> = namespace_imports.to_vec();
    for target in alias_map.values() {
        if !class_fqns.contains(target) && !is_csharp_system_or_microsoft_namespace(target) {
            out.push(target.clone());
        }
    }
    out.sort();
    out.dedup();
    out
}

/// Resolve a simple type name to a class FQN using file namespace, usings, and the batch index.
fn resolve_csharp_type_fqn(
    simple: &str,
    current_ns: Option<&str>,
    namespace_imports: &[String],
    alias_map: &HashMap<String, String>,
    index: &CSharpBatchIndex,
) -> Option<String> {
    if let Some(target) = alias_map.get(simple) {
        if index.class_fqns.contains(target) {
            return Some(target.clone());
        }
    }

    let imports = csharp_effective_import_namespaces(namespace_imports, alias_map, &index.class_fqns);

    let candidates: Vec<String> = index
        .simple_name_to_fqns
        .get(simple)
        .cloned()
        .unwrap_or_default();

    let mut filtered: Vec<String> = candidates
        .into_iter()
        .filter(|fqn| {
            let Some((decl_ns, base_name)) = fqn.rsplit_once('.') else {
                return false;
            };
            if base_name != simple {
                return false;
            }
            if Some(decl_ns) == current_ns {
                return true;
            }
            imports.iter().any(|im| im.as_str() == decl_ns)
        })
        .collect();

    if filtered.is_empty() {
        return current_ns.map(|ns| format!("{ns}.{simple}"));
    }

    if filtered.len() == 1 {
        return Some(filtered.pop().expect("one element"));
    }

    if let Some(ns) = current_ns {
        if let Some(hit) = filtered
            .iter()
            .find(|fqn| fqn.rsplit_once('.').map(|(d, _)| d) == Some(ns))
        {
            return Some(hit.clone());
        }
    }

    filtered.sort();
    Some(filtered[0].clone())
}

/// BCL type names for static call resolution (receiver is a lone identifier, no local/field).
fn csharp_well_known_static_type(name: &str) -> Option<&'static str> {
    match name {
        "Console" => Some("System.Console"),
        "String" => Some("System.String"),
        "Math" => Some("System.Math"),
        "Object" => Some("System.Object"),
        "Environment" => Some("System.Environment"),
        _ => None,
    }
}

fn csharp_node_text(node: Node, source: &str) -> Option<String> {
    let s = node.start_byte() as usize;
    let e = node.end_byte() as usize;
    source.get(s..e).map(str::trim).map(String::from)
}

/// Strip generics and take the last dotted segment for type resolution heuristics.
fn csharp_type_text_to_simple_for_resolve(type_text: &str) -> String {
    let t = type_text.split('<').next().unwrap_or(type_text).trim();
    t.split('.').last().unwrap_or(t).trim().to_string()
}

fn csharp_resolve_type_node_to_fqn(
    type_node: Node,
    source: &str,
    namespace: Option<&str>,
    using_summary: &CSharpUsingSummary,
    index: &CSharpBatchIndex,
) -> Option<String> {
    let raw = csharp_node_text(type_node, source)?;
    if raw == "var" || raw.is_empty() {
        return None;
    }
    let simple = csharp_type_text_to_simple_for_resolve(&raw);
    if simple.is_empty() {
        return None;
    }
    resolve_csharp_type_fqn(
        &simple,
        namespace,
        &using_summary.namespace_imports,
        &using_summary.alias_map,
        index,
    )
}

fn csharp_variable_declaration_child(node: Node) -> Option<Node> {
    for i in 0..node.child_count() {
        if let Some(c) = node.child(i) {
            if c.kind() == "variable_declaration" {
                return Some(c);
            }
        }
    }
    None
}

fn csharp_collect_variable_declaration_bindings(
    var_decl: Node,
    source: &str,
    namespace: Option<&str>,
    using_summary: &CSharpUsingSummary,
    index: &CSharpBatchIndex,
    out: &mut HashMap<String, String>,
) {
    let Some(type_node) = var_decl.child_by_field_name("type") else {
        return;
    };
    let Some(type_fqn) =
        csharp_resolve_type_node_to_fqn(type_node, source, namespace, using_summary, index)
    else {
        return;
    };
    for i in 0..var_decl.child_count() {
        let Some(child) = var_decl.child(i) else {
            continue;
        };
        if child.kind() != "variable_declarator" {
            continue;
        }
        let Some(id) = child.child(0).filter(|c| c.kind() == "identifier") else {
            continue;
        };
        if let Some(name) = csharp_node_text(id, source) {
            out.insert(name, type_fqn.clone());
        }
    }
}

fn csharp_collect_fields_for_type_declaration(
    type_decl: Node,
    source: &str,
    namespace: Option<&str>,
    using_summary: &CSharpUsingSummary,
    index: &CSharpBatchIndex,
) -> HashMap<String, String> {
    let mut fields = HashMap::new();
    if !matches!(
        type_decl.kind(),
        "class_declaration"
            | "interface_declaration"
            | "struct_declaration"
            | "enum_declaration"
            | "record_declaration"
            | "record_struct_declaration"
    ) {
        return fields;
    }
    let Some(body) = type_decl.child_by_field_name("body") else {
        return fields;
    };
    for i in 0..body.child_count() {
        let Some(member) = body.child(i) else {
            continue;
        };
        if member.kind() != "field_declaration" {
            continue;
        }
        let Some(vd) = csharp_variable_declaration_child(member) else {
            continue;
        };
        csharp_collect_variable_declaration_bindings(
            vd,
            source,
            namespace,
            using_summary,
            index,
            &mut fields,
        );
    }
    fields
}

fn csharp_collect_locals_in_scope(
    scope_root: Node,
    source: &str,
    namespace: Option<&str>,
    using_summary: &CSharpUsingSummary,
    index: &CSharpBatchIndex,
) -> HashMap<String, String> {
    let mut locals = HashMap::new();
    walk_tree(scope_root, |n| {
        if n.kind() != "local_declaration_statement" {
            return;
        }
        let Some(vd) = csharp_variable_declaration_child(n) else {
            return;
        };
        csharp_collect_variable_declaration_bindings(
            vd,
            source,
            namespace,
            using_summary,
            index,
            &mut locals,
        );
    });
    locals
}

fn csharp_type_declaration_kind_str(decl_kind: &str) -> &'static str {
    match decl_kind {
        "enum_declaration" => "enum",
        "interface_declaration" => "interface",
        "struct_declaration" => "struct",
        "record_struct_declaration" => "struct",
        "record_declaration" => "record",
        _ => "class",
    }
}

/// FQN for a type declaration node, including outer nesting (`Ns.Outer.Inner`) and
/// nested `namespace` blocks (CRM-3586). `legacy_file_namespace` is used only when no
/// enclosing `namespace_declaration` / `file_scoped_namespace_declaration` applies.
fn csharp_fqn_for_type_declaration(
    decl: Node,
    source: &str,
    legacy_file_namespace: Option<&str>,
) -> Option<String> {
    let leaf_name = identifier_text_from_children(decl, source)?;
    let mut segments = vec![leaf_name];
    let mut cur = decl.parent();
    while let Some(p) = cur {
        let pk = p.kind();
        if matches!(
            pk,
            "class_declaration"
                | "interface_declaration"
                | "struct_declaration"
                | "enum_declaration"
                | "record_declaration"
                | "record_struct_declaration"
        ) {
            if let Some(n) = identifier_text_from_children(p, source) {
                segments.push(n);
            }
        }
        cur = p.parent();
    }
    segments.reverse();
    let qualified = segments.join(".");
    let ns = csharp_enclosing_namespace_prefix(decl, source)
        .or_else(|| legacy_file_namespace.map(|s| s.to_string()));
    Some(match ns {
        Some(n) => format!("{n}.{qualified}"),
        None => qualified,
    })
}

fn csharp_innermost_enclosing_type_declaration(from: Node) -> Option<Node> {
    let mut cur = from.parent();
    while let Some(p) = cur {
        let pk = p.kind();
        if matches!(
            pk,
            "class_declaration"
                | "interface_declaration"
                | "struct_declaration"
                | "enum_declaration"
                | "record_declaration"
                | "record_struct_declaration"
        ) {
            return Some(p);
        }
        cur = p.parent();
    }
    None
}

/// Caller / `Function.fqn` for instance constructors: `{class_fqn}.ctor#{arity}` (CRM-3587).
fn csharp_constructor_function_fqn(class_fqn: &str, arity: usize) -> String {
    format!("{class_fqn}.ctor#{arity}")
}

/// `(name, fqn)` for constructor symbols and call-graph callers; static ctor uses `{class_fqn}.cctor`.
fn csharp_constructor_symbol_fqn(ctor: Node, class_fqn: &str, source: &str) -> (String, String) {
    let modifiers = csharp_collect_method_modifiers(ctor, source);
    if modifiers.iter().any(|m| m == "static") {
        return ("cctor".to_string(), format!("{class_fqn}.cctor"));
    }
    let param_types = csharp_method_parameter_types(ctor, source);
    let arity = param_types.len();
    (
        format!("ctor#{arity}"),
        csharp_constructor_function_fqn(class_fqn, arity),
    )
}

fn csharp_method_simple_name(method: Node, source: &str) -> Option<String> {
    method
        .child_by_field_name("name")
        .and_then(|n| csharp_node_text(n, source))
        .filter(|s| !s.is_empty())
        .or_else(|| identifier_text_from_children(method, source))
}

fn csharp_collect_method_modifiers(method: Node, source: &str) -> Vec<String> {
    let mut out = Vec::new();
    for i in 0..method.child_count() {
        let Some(c) = method.child(i) else {
            continue;
        };
        if c.kind() == "modifier" {
            if let Some(t) = csharp_node_text(c, source) {
                if !t.is_empty() {
                    out.push(t);
                }
            }
        }
    }
    out
}

/// Return-type node: tree-sitter-c-sharp 0.23+ uses field `returns`; older grammars used `type`.
fn csharp_method_return_type_node(method: Node) -> Option<Node> {
    method
        .child_by_field_name("returns")
        .or_else(|| method.child_by_field_name("type"))
}

fn csharp_method_return_type_string(method: Node, source: &str) -> Option<String> {
    let t = csharp_method_return_type_node(method)?;
    if t.kind() == "void_keyword" {
        return Some("void".to_string());
    }
    csharp_node_text(t, source)
}

fn csharp_method_parameter_types(method: Node, source: &str) -> Vec<String> {
    let mut out = Vec::new();
    let Some(params) = method.child_by_field_name("parameters") else {
        return out;
    };
    for i in 0..params.child_count() {
        let Some(p) = params.child(i) else {
            continue;
        };
        if p.kind() != "parameter" {
            continue;
        }
        let Some(ty) = p.child_by_field_name("type") else {
            continue;
        };
        if let Some(s) = csharp_node_text(ty, source) {
            if !s.is_empty() {
                out.push(s);
            }
        }
    }
    out
}

fn csharp_enclosing_type_fqn(node: Node, source: &str, namespace: Option<&str>) -> Option<String> {
    let inner = csharp_innermost_enclosing_type_declaration(node)?;
    csharp_fqn_for_type_declaration(inner, source, namespace)
}

fn csharp_block_body(node: Node) -> Option<Node> {
    for i in 0..node.child_count() {
        if let Some(c) = node.child(i) {
            if c.kind() == "block" {
                return Some(c);
            }
        }
    }
    None
}

fn csharp_property_name_for_accessor(acc: Node, source: &str) -> Option<String> {
    let list = acc.parent()?;
    let prop = list.parent()?;
    if prop.kind() != "property_declaration" {
        return None;
    }
    let name_node = prop.child_by_field_name("name")?;
    csharp_node_text(name_node, source)
}

fn csharp_accessor_kind_prefix(acc: Node, source: &str) -> &'static str {
    for i in 0..acc.child_count() {
        if let Some(c) = acc.child(i) {
            if let Some(t) = csharp_node_text(c, source) {
                match t.as_str() {
                    "get" => return "get",
                    "set" => return "set",
                    "init" => return "init",
                    _ => {}
                }
            }
        }
    }
    "accessor"
}

fn csharp_method_name_from_simple_name_node(node: Node, source: &str) -> Option<String> {
    match node.kind() {
        "identifier" => csharp_node_text(node, source),
        "generic_name" => node
            .child(0)
            .filter(|c| c.kind() == "identifier")
            .and_then(|c| csharp_node_text(c, source)),
        _ => {
            let t = csharp_node_text(node, source)?;
            Some(csharp_type_text_to_simple_for_resolve(&t))
        }
    }
}

fn csharp_unwrap_parenthesized_invoke_expr(mut expr: Node) -> Node {
    while expr.kind() == "parenthesized_expression" {
        if let Some(inner) = expr.child(1) {
            expr = inner;
        } else {
            break;
        }
    }
    expr
}

fn csharp_resolve_member_receiver_to_type_fqn(
    mut receiver: Node,
    source: &str,
    class_fqn: Option<&str>,
    field_map: &HashMap<String, String>,
    local_map: &HashMap<String, String>,
    namespace: Option<&str>,
    using_summary: &CSharpUsingSummary,
    index: &CSharpBatchIndex,
) -> Option<String> {
    while receiver.kind() == "member_access_expression" {
        receiver = receiver.child_by_field_name("expression")?;
    }
    match receiver.kind() {
        // tree-sitter-c-sharp 0.23+: `this` / `base` are anonymous nodes; older grammars used *_expression.
        "this_expression" | "base_expression" | "this" | "base" => class_fqn.map(String::from),
        "identifier" => {
            let name = csharp_node_text(receiver, source)?;
            if let Some(t) = local_map.get(&name) {
                return Some(t.clone());
            }
            if let Some(t) = field_map.get(&name) {
                return Some(t.clone());
            }
            if let Some(wk) = csharp_well_known_static_type(&name) {
                return Some(wk.to_string());
            }
            resolve_csharp_type_fqn(
                &name,
                namespace,
                &using_summary.namespace_imports,
                &using_summary.alias_map,
                index,
            )
        }
        _ => None,
    }
}

fn csharp_resolve_invocation_callee_fqn(
    fn_expr: Node,
    source: &str,
    class_fqn: Option<&str>,
    field_map: &HashMap<String, String>,
    local_map: &HashMap<String, String>,
    namespace: Option<&str>,
    using_summary: &CSharpUsingSummary,
    index: &CSharpBatchIndex,
) -> Option<String> {
    let fn_expr = csharp_unwrap_parenthesized_invoke_expr(fn_expr);
    match fn_expr.kind() {
        "identifier" => {
            let name = csharp_node_text(fn_expr, source)?;
            if let Some(cls) = class_fqn {
                Some(format!("{cls}.{name}"))
            } else if let Some(ns) = namespace {
                Some(format!("{ns}.{name}"))
            } else {
                Some(name)
            }
        }
        "generic_name" => {
            let name = csharp_method_name_from_simple_name_node(fn_expr, source)?;
            if let Some(cls) = class_fqn {
                Some(format!("{cls}.{name}"))
            } else if let Some(ns) = namespace {
                Some(format!("{ns}.{name}"))
            } else {
                Some(name)
            }
        }
        "member_access_expression" => {
            let name_node = fn_expr.child_by_field_name("name")?;
            let method_name = csharp_method_name_from_simple_name_node(name_node, source)?;
            let recv = fn_expr.child_by_field_name("expression")?;
            let recv_ty = csharp_resolve_member_receiver_to_type_fqn(
                recv,
                source,
                class_fqn,
                field_map,
                local_map,
                namespace,
                using_summary,
                index,
            )?;
            Some(format!("{recv_ty}.{method_name}"))
        }
        _ => None,
    }
}

fn csharp_collect_calls_from_body(
    body: Node,
    caller_fqn: &str,
    class_fqn: Option<&str>,
    field_map: &HashMap<String, String>,
    source: &str,
    namespace: Option<&str>,
    using_summary: &CSharpUsingSummary,
    index: &CSharpBatchIndex,
    calls: &mut Vec<(String, String)>,
) {
    let locals = csharp_collect_locals_in_scope(body, source, namespace, using_summary, index);
    walk_tree(body, |n| {
        if n.kind() != "invocation_expression" {
            return;
        }
        let Some(fn_node) = n.child_by_field_name("function") else {
            return;
        };
        let Some(callee) = csharp_resolve_invocation_callee_fqn(
            fn_node,
            source,
            class_fqn,
            field_map,
            &locals,
            namespace,
            using_summary,
            index,
        ) else {
            return;
        };
        calls.push((caller_fqn.to_string(), callee));
    });
}

/// Extract C# classes (including records), methods, constructors, property accessors, and properties.
///
/// Type FQNs include nesting (`Ns.Outer.Inner`). Method metadata uses raw type
/// text from the declaration (CRM-3594). Constructor and accessor `fqn` values
/// align with [`extract_csharp_calls`] (CRM-3587).
fn extract_csharp_symbols(
    tree: &Tree,
    source: &str,
) -> (
    Vec<ClassSymbol>,
    Vec<FunctionSymbol>,
    Vec<PropertySymbol>,
) {
    let mut classes: Vec<ClassSymbol> = Vec::new();
    let mut methods: Vec<FunctionSymbol> = Vec::new();
    let mut properties: Vec<PropertySymbol> = Vec::new();
    let mut seen_class_fqns: HashSet<String> = HashSet::new();
    let mut seen_property_fqns: HashSet<String> = HashSet::new();

    let namespace = extract_csharp_namespace(tree, source);
    let root = tree.root_node();

    walk_tree(root, |node| {
        let nk = node.kind();
        match nk {
            "class_declaration"
            | "interface_declaration"
            | "struct_declaration"
            | "enum_declaration"
            | "record_declaration"
            | "record_struct_declaration" => {
                let Some(name) = identifier_text_from_children(node, source) else {
                    return;
                };
                let Some(fqn) = csharp_fqn_for_type_declaration(node, source, namespace.as_deref()) else {
                    return;
                };
                if seen_class_fqns.insert(fqn.clone()) {
                    let kind = Some(csharp_type_declaration_kind_str(nk));
                    classes.push(ClassSymbol { name, fqn, kind });
                }
            }
            "method_declaration" => {
                let Some(method_name) = csharp_method_simple_name(node, source) else {
                    return;
                };
                let class_fqn = csharp_enclosing_type_fqn(node, source, namespace.as_deref());
                let fqn = if let Some(ref cls) = class_fqn {
                    format!("{cls}.{method_name}")
                } else if let Some(ref ns) = namespace {
                    format!("{ns}.{method_name}")
                } else {
                    method_name.clone()
                };

                let param_types = csharp_method_parameter_types(node, source);
                let param_count = param_types.len();
                let return_type = csharp_method_return_type_string(node, source);
                let modifiers = csharp_collect_method_modifiers(node, source);

                methods.push(FunctionSymbol {
                    name: method_name,
                    fqn,
                    class_fqn,
                    return_type,
                    param_types,
                    param_count,
                    modifiers,
                    is_pointer_receiver: None,
                });
            }
            "constructor_declaration" => {
                let Some(class_fqn) =
                    csharp_enclosing_type_fqn(node, source, namespace.as_deref())
                else {
                    return;
                };
                let (name, fqn) = csharp_constructor_symbol_fqn(node, &class_fqn, source);
                let param_types = csharp_method_parameter_types(node, source);
                let param_count = param_types.len();
                let modifiers = csharp_collect_method_modifiers(node, source);
                methods.push(FunctionSymbol {
                    name,
                    fqn,
                    class_fqn: Some(class_fqn),
                    return_type: None,
                    param_types,
                    param_count,
                    modifiers,
                    is_pointer_receiver: None,
                });
            }
            "property_declaration" => {
                let Some(class_fqn) =
                    csharp_enclosing_type_fqn(node, source, namespace.as_deref())
                else {
                    return;
                };
                let Some(prop_name_node) = node.child_by_field_name("name") else {
                    return;
                };
                let Some(prop_name) = csharp_node_text(prop_name_node, source).filter(|s| !s.is_empty())
                else {
                    return;
                };
                let prop_fqn = format!("{class_fqn}.{prop_name}");
                if seen_property_fqns.insert(prop_fqn.clone()) {
                    let declared_type = node
                        .child_by_field_name("type")
                        .and_then(|t| csharp_node_text(t, source))
                        .filter(|s| !s.is_empty());
                    properties.push(PropertySymbol {
                        class_fqn: class_fqn.clone(),
                        name: prop_name.clone(),
                        fqn: prop_fqn,
                        declared_type,
                    });
                }
                let prop_type_text = node
                    .child_by_field_name("type")
                    .and_then(|t| csharp_node_text(t, source))
                    .filter(|s| !s.is_empty());
                let Some(accessor_list) = node.child_by_field_name("accessors") else {
                    return;
                };
                for i in 0..accessor_list.child_count() {
                    let Some(acc) = accessor_list.child(i) else {
                        continue;
                    };
                    if acc.kind() != "accessor_declaration" {
                        continue;
                    }
                    let prefix = csharp_accessor_kind_prefix(acc, source);
                    let fn_name = format!("{prefix}_{prop_name}");
                    let fqn = format!("{class_fqn}.{fn_name}");
                    let return_type = match prefix {
                        "get" => prop_type_text.clone(),
                        "set" | "init" => Some("void".to_string()),
                        _ => prop_type_text.clone(),
                    };
                    let param_types = csharp_method_parameter_types(acc, source);
                    let param_count = param_types.len();
                    let modifiers = csharp_collect_method_modifiers(acc, source);
                    methods.push(FunctionSymbol {
                        name: fn_name,
                        fqn,
                        class_fqn: Some(class_fqn.clone()),
                        return_type,
                        param_types,
                        param_count,
                        modifiers,
                        is_pointer_receiver: None,
                    });
                }
            }
            _ => {}
        }
    });

    (classes, methods, properties)
}

/// Visit each unique `_type` subtree root from explicit type positions (CRM-3589 F-16);
/// skips nested local functions. Roots are deduped by byte span.
fn csharp_for_each_unique_type_root(method: Node, seen: &mut HashSet<(usize, usize)>, f: &mut impl FnMut(Node)) {
    let mut push = |n: Option<Node>| {
        let Some(t) = n else {
            return;
        };
        if t.kind() == "void_keyword" {
            return;
        }
        let key = (t.start_byte() as usize, t.end_byte() as usize);
        if seen.insert(key) {
            f(t);
        }
    };

    push(csharp_method_return_type_node(method));

    walk_tree_skip_local_functions(method, |n| {
        match n.kind() {
            "local_declaration_statement" => {
                if let Some(vd) = csharp_variable_declaration_child(n) {
                    push(vd.child_by_field_name("type"));
                }
            }
            "variable_declaration" | "parameter" | "object_creation_expression" | "cast_expression"
            | "default_expression" => {
                push(n.child_by_field_name("type"));
            }
            "as_expression" | "is_expression" => {
                push(n.child_by_field_name("right"));
            }
            "type_pattern" => {
                if let Some(c) = n.named_child(0) {
                    push(Some(c));
                }
            }
            _ => {}
        }
    });
}

/// Walk a `_type` subtree and collect simple names for [`resolve_csharp_type_fqn`].
fn csharp_collect_simple_type_names_from_type_node(node: Node, source: &str, out: &mut Vec<String>) {
    match node.kind() {
        "type_identifier" | "identifier" => {
            if let Some(t) = csharp_node_text(node, source) {
                out.push(t);
            }
        }
        "generic_name" => {
            for i in 0..node.child_count() {
                let Some(c) = node.child(i) else {
                    continue;
                };
                match c.kind() {
                    "identifier" => {
                        if let Some(t) = csharp_node_text(c, source) {
                            out.push(t);
                        }
                    }
                    "type_argument_list" => {
                        for j in 0..c.named_child_count() {
                            if let Some(arg) = c.named_child(j) {
                                csharp_collect_simple_type_names_from_type_node(arg, source, out);
                            }
                        }
                    }
                    _ => {}
                }
            }
        }
        "qualified_name" => {
            for i in 0..node.child_count() {
                let Some(c) = node.child(i) else {
                    continue;
                };
                match c.kind() {
                    "qualified_name" | "alias_qualified_name" | "generic_name" | "type_identifier"
                    | "identifier" => {
                        csharp_collect_simple_type_names_from_type_node(c, source, out);
                    }
                    _ => {}
                }
            }
        }
        "alias_qualified_name" => {
            for i in 0..node.child_count() {
                let Some(c) = node.child(i) else {
                    continue;
                };
                if matches!(c.kind(), "generic_name" | "identifier" | "type_identifier") {
                    csharp_collect_simple_type_names_from_type_node(c, source, out);
                }
            }
        }
        "nullable_type" => {
            if let Some(c) = node.named_child(0) {
                csharp_collect_simple_type_names_from_type_node(c, source, out);
            }
        }
        "array_type" => {
            if let Some(c) = node.child_by_field_name("type") {
                csharp_collect_simple_type_names_from_type_node(c, source, out);
            }
        }
        "pointer_type" => {
            if let Some(c) = node.named_child(0) {
                csharp_collect_simple_type_names_from_type_node(c, source, out);
            }
        }
        "tuple_type" => {
            for i in 0..node.named_child_count() {
                let Some(el) = node.named_child(i) else {
                    continue;
                };
                if el.kind() == "tuple_element" {
                    if let Some(tn) = el.child_by_field_name("type") {
                        csharp_collect_simple_type_names_from_type_node(tn, source, out);
                    }
                }
            }
        }
        "predefined_type" => {}
        _ => {
            if let Some(inner) = node.child_by_field_name("type") {
                csharp_collect_simple_type_names_from_type_node(inner, source, out);
            }
        }
    }
}

fn csharp_for_each_base_type_in_list(base_list: Node, mut f: impl FnMut(Node)) {
    for i in 0..base_list.child_count() {
        let Some(c) = base_list.child(i) else {
            continue;
        };
        match c.kind() {
            ":" | "," => continue,
            // Constructor call on base type in primary ctor / record bases
            "argument_list" => continue,
            _ => f(c),
        }
    }
}

/// Base clause: older grammars used field `bases`; 0.23+ uses a `base_list` named child.
fn csharp_type_declaration_base_list(decl: Node) -> Option<Node> {
    decl.child_by_field_name("bases")
        .filter(|b| !b.is_missing())
        .or_else(|| {
            (0..decl.named_child_count())
                .filter_map(|i| decl.named_child(i))
                .find(|c| c.kind() == "base_list")
        })
}

/// `(:Class)-[:USES_CLASS]->(:Class)` pairs for base types and interfaces (CRM-3584).
fn extract_csharp_class_inheritance_edges(
    tree: &Tree,
    source: &str,
    legacy_ns: Option<&str>,
    using_summary: &CSharpUsingSummary,
    index: &CSharpBatchIndex,
) -> Vec<(String, String)> {
    let mut out = Vec::new();
    let mut seen: HashSet<(String, String)> = HashSet::new();
    let root = tree.root_node();
    walk_tree(root, |n| {
        if !matches!(
            n.kind(),
            "class_declaration" | "interface_declaration" | "struct_declaration" | "record_declaration"
        ) {
            return;
        }
        let Some(derived_fqn) = csharp_fqn_for_type_declaration(n, source, legacy_ns) else {
            return;
        };
        let Some(bases_field) = csharp_type_declaration_base_list(n) else {
            return;
        };
        if bases_field.is_missing() {
            return;
        }
        let ns_for = csharp_enclosing_namespace_prefix(n, source)
            .or_else(|| legacy_ns.map(|s| s.to_string()));
        csharp_for_each_base_type_in_list(bases_field, |ty_node| {
            let mut names: Vec<String> = Vec::new();
            csharp_collect_simple_type_names_from_type_node(ty_node, source, &mut names);
            let Some(simple) = names.first() else {
                return;
            };
            if is_csharp_builtin_type(simple) {
                return;
            }
            let base_fqn = resolve_csharp_type_fqn(
                simple,
                ns_for.as_deref(),
                &using_summary.namespace_imports,
                &using_summary.alias_map,
                index,
            )
            .unwrap_or_else(|| {
                ns_for
                    .as_ref()
                    .map(|ns| format!("{ns}.{simple}"))
                    .unwrap_or_else(|| simple.clone())
            });
            if base_fqn != derived_fqn && seen.insert((derived_fqn.clone(), base_fqn.clone())) {
                out.push((derived_fqn.clone(), base_fqn));
            }
        });
    });
    out
}

/// Single-letter uppercase names are usually generic type parameters (CRM-3589).
fn csharp_is_likely_type_parameter_name(name: &str) -> bool {
    let mut it = name.chars();
    match (it.next(), it.next()) {
        (Some(c), None) if c.is_ascii_uppercase() => true,
        _ => false,
    }
}

/// Extract `USES_CLASS` from **type syntax sites** only (not arbitrary identifiers), with an
/// expanded BCL filter (CRM-3589 F-16 / F-17). Nested `local_function_statement` bodies are excluded.
fn extract_csharp_used_classes(
    tree: &Tree,
    source: &str,
    namespace: Option<&str>,
    using_summary: &CSharpUsingSummary,
    csharp_index: &CSharpBatchIndex,
) -> Vec<(String, String)> {
    let mut uses: Vec<(String, String)> = Vec::new();
    let mut pair_seen: HashSet<(String, String)> = HashSet::new();
    let root = tree.root_node();

    walk_tree(root, |node| {
        if node.kind() != "method_declaration" {
            return;
        }

        let Some(method_name) = csharp_method_simple_name(node, source) else {
            return;
        };

        let effective_ns = csharp_enclosing_namespace_prefix(node, source)
            .or_else(|| namespace.map(|s| s.to_string()));
        let class_fqn = csharp_enclosing_type_fqn(node, source, namespace);
        let func_fqn = if let Some(ref cls) = class_fqn {
            format!("{cls}.{method_name}")
        } else if let Some(ref ns) = effective_ns {
            format!("{ns}.{method_name}")
        } else {
            method_name
        };

        let mut root_seen: HashSet<(usize, usize)> = HashSet::new();
        let mut simple_names: Vec<String> = Vec::new();
        csharp_for_each_unique_type_root(node, &mut root_seen, &mut |tr| {
            csharp_collect_simple_type_names_from_type_node(tr, source, &mut simple_names);
        });

        for type_name in simple_names {
            if is_csharp_builtin_type(&type_name) {
                continue;
            }
            if csharp_is_likely_type_parameter_name(&type_name)
                && !using_summary.alias_map.contains_key(&type_name)
            {
                continue;
            }
            if !type_name
                .chars()
                .next()
                .map(|c| c.is_uppercase())
                .unwrap_or(false)
            {
                continue;
            }
            let type_fqn = resolve_csharp_type_fqn(
                &type_name,
                effective_ns.as_deref(),
                &using_summary.namespace_imports,
                &using_summary.alias_map,
                csharp_index,
            )
            .unwrap_or_else(|| {
                effective_ns
                    .as_ref()
                    .map(|ns| format!("{ns}.{type_name}"))
                    .unwrap_or_else(|| type_name.clone())
            });
            if pair_seen.insert((func_fqn.clone(), type_fqn.clone())) {
                uses.push((func_fqn.clone(), type_fqn));
            }
        }
    });

    uses
}

/// Keywords / CLR aliases (F-17).
fn is_csharp_primitive_or_alias(name: &str) -> bool {
    matches!(
        name,
        "int" | "long" | "short" | "byte" | "float" | "double" | "decimal"
            | "bool" | "char" | "string" | "object" | "void" | "dynamic" | "var"
            | "nint" | "nuint"
            | "Int32" | "Int64" | "Int16" | "UInt32" | "UInt64" | "UInt16"
            | "Byte" | "SByte" | "Single" | "Double" | "Decimal"
            | "Boolean" | "Char" | "String" | "Object" | "Void"
    )
}

/// Common BCL / framework types that rarely need `USES_CLASS` edges for impact analysis (F-17).
fn is_csharp_common_bcl_or_framework_type(name: &str) -> bool {
    matches!(
        name,
        // Collections & LINQ
        "List" | "Dictionary" | "IEnumerable" | "IEnumerator" | "IList" | "ICollection" | "IDictionary"
            | "IReadOnlyList" | "IReadOnlyCollection" | "IReadOnlyDictionary" | "ISet" | "HashSet"
            | "SortedSet" | "Queue" | "Stack" | "LinkedList" | "SortedList" | "ConcurrentBag"
            | "ConcurrentQueue" | "ConcurrentStack" | "ConcurrentDictionary" | "ObservableCollection"
            | "ImmutableArray" | "ImmutableList" | "ImmutableDictionary" | "IOrderedEnumerable"
        // Async / threading
            | "Task" | "ValueTask" | "CancellationToken" | "CancellationTokenSource"
            | "IAsyncEnumerable" | "IAsyncEnumerator" | "Parallel" | "Thread" | "Interlocked"
        // Delegates
            | "Func" | "Action" | "MulticastDelegate" | "Delegate"
        // Date/time / core value types
            | "DateTime" | "DateTimeOffset" | "TimeSpan" | "DateOnly" | "TimeOnly" | "Guid"
        // Text / IO
            | "StringBuilder" | "Encoding" | "UTF8Encoding" | "ASCIIEncoding" | "UnicodeEncoding"
            | "Stream" | "MemoryStream" | "FileStream" | "BufferedStream" | "TextReader" | "TextWriter"
            | "StringReader" | "StringWriter" | "BinaryReader" | "BinaryWriter" | "File" | "Path"
            | "Directory" | "Environment"
        // Reflection / core
            | "Uri" | "Version" | "Type" | "Enum" | "Array" | "Nullable" | "Lazy" | "Tuple"
            | "ValueTuple" | "Console" | "Math" | "Convert" | "BitConverter" | "GC" | "WeakReference"
            | "RuntimeHelpers" | "Activator"
        // Exceptions
            | "Exception" | "ArgumentException" | "ArgumentNullException" | "ArgumentOutOfRangeException"
            | "InvalidOperationException" | "NotSupportedException" | "NotImplementedException"
            | "IOException" | "UnauthorizedAccessException" | "TimeoutException" | "AggregateException"
            | "OperationCanceledException" | "ObjectDisposedException" | "FormatException"
        // Span / memory
            | "Span" | "ReadOnlySpan" | "Memory" | "ReadOnlyMemory"
        // Common interfaces (may hide a same-named domain type — tradeoff per CRM-3589)
            | "IDisposable" | "IAsyncDisposable" | "IComparable" | "IEquatable" | "IFormattable"
            | "IServiceProvider" | "ILogger" | "IConfiguration" | "IHost" | "IHostedService"
            | "IHttpClientFactory" | "HttpClient" | "HttpRequestMessage" | "HttpResponseMessage"
    )
}

fn is_csharp_builtin_type(name: &str) -> bool {
    is_csharp_primitive_or_alias(name) || is_csharp_common_bcl_or_framework_type(name)
}

/// Extract C# method calls for CALLS_FUNCTION edges (methods, constructors, property accessors).
fn extract_csharp_calls(
    tree: &Tree,
    source: &str,
    namespace: Option<&str>,
    using_summary: &CSharpUsingSummary,
    csharp_index: &CSharpBatchIndex,
) -> Vec<(String, String)> {
    let mut calls: Vec<(String, String)> = Vec::new();
    let root = tree.root_node();
    let mut class_field_maps: HashMap<String, HashMap<String, String>> = HashMap::new();

    walk_tree(root, |node| {
        if matches!(
            node.kind(),
            "class_declaration"
                | "interface_declaration"
                | "struct_declaration"
                | "enum_declaration"
                | "record_declaration"
                | "record_struct_declaration"
        ) {
            if let Some(cfqn) = csharp_fqn_for_type_declaration(node, source, namespace) {
                let ns_for = csharp_enclosing_namespace_prefix(node, source)
                    .or_else(|| namespace.map(|s| s.to_string()));
                let fm = csharp_collect_fields_for_type_declaration(
                    node,
                    source,
                    ns_for.as_deref(),
                    using_summary,
                    csharp_index,
                );
                class_field_maps.insert(cfqn, fm);
            }
        }
    });

    let empty_fields: HashMap<String, String> = HashMap::new();

    walk_tree(root, |node| {
        match node.kind() {
            "method_declaration" => {
                let Some(method_name) = csharp_method_simple_name(node, source) else {
                    return;
                };
                let effective_ns = csharp_enclosing_namespace_prefix(node, source)
                    .or_else(|| namespace.map(|s| s.to_string()));
                let class_fqn = csharp_enclosing_type_fqn(node, source, namespace);
                let caller_fqn = match &class_fqn {
                    Some(cf) => format!("{cf}.{method_name}"),
                    None => effective_ns
                        .as_ref()
                        .map(|ns| format!("{ns}.{method_name}"))
                        .unwrap_or(method_name),
                };
                let Some(body) = csharp_block_body(node) else {
                    return;
                };
                let field_map = class_fqn
                    .as_ref()
                    .and_then(|c| class_field_maps.get(c))
                    .unwrap_or(&empty_fields);
                csharp_collect_calls_from_body(
                    body,
                    &caller_fqn,
                    class_fqn.as_deref(),
                    field_map,
                    source,
                    effective_ns.as_deref(),
                    using_summary,
                    csharp_index,
                    &mut calls,
                );
            }
            "constructor_declaration" => {
                let class_fqn = csharp_enclosing_type_fqn(node, source, namespace);
                let Some(cf) = class_fqn.clone() else {
                    return;
                };
                let effective_ns = csharp_enclosing_namespace_prefix(node, source)
                    .or_else(|| namespace.map(|s| s.to_string()));
                let (_, caller_fqn) = csharp_constructor_symbol_fqn(node, &cf, source);
                let Some(body) = csharp_block_body(node) else {
                    return;
                };
                let field_map = class_field_maps.get(&cf).unwrap_or(&empty_fields);
                csharp_collect_calls_from_body(
                    body,
                    &caller_fqn,
                    Some(cf.as_str()),
                    field_map,
                    source,
                    effective_ns.as_deref(),
                    using_summary,
                    csharp_index,
                    &mut calls,
                );
            }
            "accessor_declaration" => {
                let class_fqn = csharp_enclosing_type_fqn(node, source, namespace);
                let Some(cf) = class_fqn.clone() else {
                    return;
                };
                let effective_ns = csharp_enclosing_namespace_prefix(node, source)
                    .or_else(|| namespace.map(|s| s.to_string()));
                let Some(prop_name) = csharp_property_name_for_accessor(node, source) else {
                    return;
                };
                let prefix = csharp_accessor_kind_prefix(node, source);
                let caller_fqn = format!("{cf}.{}_{}", prefix, prop_name);
                let Some(body) = csharp_block_body(node) else {
                    return;
                };
                let field_map = class_field_maps.get(&cf).unwrap_or(&empty_fields);
                csharp_collect_calls_from_body(
                    body,
                    &caller_fqn,
                    Some(cf.as_str()),
                    field_map,
                    source,
                    effective_ns.as_deref(),
                    using_summary,
                    csharp_index,
                    &mut calls,
                );
            }
            _ => {}
        }
    });

    calls
}

/// Decode a C# `string_literal` or `verbatim_string_literal` node's content (no quotes).
fn csharp_string_value_from_literal_node(node: Node, source: &str) -> Option<String> {
    let s = source.get(node.start_byte() as usize..node.end_byte() as usize)?;
    let t = s.trim();
    match node.kind() {
        "string_literal" => {
            if t.starts_with('"') && t.ends_with('"') && t.len() >= 2 {
                Some(t[1..t.len() - 1].to_string())
            } else {
                None
            }
        }
        "verbatim_string_literal" => {
            if t.starts_with("@\"") && t.ends_with('"') && t.len() >= 3 {
                Some(t[2..t.len() - 1].replace("\"\"", "\""))
            } else {
                None
            }
        }
        _ => None,
    }
}

/// First string literal under `root` (DFS pre-order), for attribute arguments.
fn csharp_first_string_in_subtree(root: Node, source: &str) -> Option<String> {
    let mut stack = vec![root];
    while let Some(n) = stack.pop() {
        match n.kind() {
            "string_literal" | "verbatim_string_literal" => {
                return csharp_string_value_from_literal_node(n, source);
            }
            _ => {
                let cc = n.child_count();
                for i in (0..cc).rev() {
                    if let Some(c) = n.child(i) {
                        stack.push(c);
                    }
                }
            }
        }
    }
    None
}

fn csharp_first_string_in_attribute(attr: Node, source: &str) -> Option<String> {
    for i in 0..attr.child_count() {
        let Some(c) = attr.child(i) else {
            continue;
        };
        if c.kind() != "attribute_argument_list" {
            continue;
        }
        for j in 0..c.named_child_count() {
            let Some(arg) = c.named_child(j) else {
                continue;
            };
            if arg.kind() == "attribute_argument" {
                if let Some(s) = csharp_first_string_in_subtree(arg, source) {
                    return Some(s);
                }
            }
        }
    }
    None
}

/// Simple name of an attribute target (`HttpGet`, `Route`, last segment of `Foo.HttpGet`).
fn csharp_attribute_simple_name_from_name_node(n: Node, source: &str) -> Option<String> {
    match n.kind() {
        "identifier" => csharp_node_text(n, source),
        "generic_name" => {
            let id = n.child(0).filter(|c| c.kind() == "identifier")?;
            csharp_node_text(id, source)
        }
        "qualified_name" | "alias_qualified_name" => {
            let mut last = None;
            for i in 0..n.child_count() {
                let Some(c) = n.child(i) else {
                    continue;
                };
                if !c.is_named() {
                    continue;
                }
                if let Some(s) = csharp_attribute_simple_name_from_name_node(c, source) {
                    last = Some(s);
                }
            }
            last
        }
        _ => None,
    }
}

fn csharp_route_path_from_str(path: &str) -> Option<String> {
    let path = path.trim();
    if path.is_empty() {
        None
    } else if path.starts_with('/') {
        Some(path.to_string())
    } else {
        Some(format!("/{}", path))
    }
}

/// Last non-empty `[Route("...")]` on a `class_declaration` / `record_declaration`.
fn csharp_type_level_route_template(type_node: Node, source: &str) -> Option<String> {
    let mut last: Option<String> = None;
    for i in 0..type_node.child_count() {
        let Some(c) = type_node.child(i) else {
            continue;
        };
        if c.kind() != "attribute_list" {
            continue;
        }
        for j in 0..c.child_count() {
            let Some(attr) = c.child(j) else {
                continue;
            };
            if attr.kind() != "attribute" {
                continue;
            }
            let Some(name_n) = attr.child_by_field_name("name") else {
                continue;
            };
            let Some(simple) = csharp_attribute_simple_name_from_name_node(name_n, source) else {
                continue;
            };
            if simple != "Route" {
                continue;
            }
            if let Some(raw) = csharp_first_string_in_attribute(attr, source) {
                last = csharp_route_path_from_str(&raw);
            }
        }
    }
    last
}

fn csharp_enclosing_route_type_for_method(method: Node) -> Option<Node> {
    let mut p = method.parent();
    while let Some(n) = p {
        let k = n.kind();
        if k == "class_declaration" || k == "record_declaration" {
            return Some(n);
        }
        p = n.parent();
    }
    None
}

fn csharp_push_http_verb(verbs: &mut Vec<String>, v: &str) {
    if !verbs.iter().any(|x| x == v) {
        verbs.push(v.to_string());
    }
}

/// `(http_verbs, template_from_http_verb_attr, template_from_route_attr)` from method `attribute_list`s.
fn csharp_parse_method_api_attributes(
    method: Node,
    source: &str,
) -> (Vec<String>, Option<String>, Option<String>) {
    let mut verbs: Vec<String> = Vec::new();
    let mut http_template: Option<String> = None;
    let mut route_attr: Option<String> = None;

    const VERB_ATTRS: &[(&str, &str)] = &[
        ("HttpGet", "GET"),
        ("HttpPost", "POST"),
        ("HttpPut", "PUT"),
        ("HttpDelete", "DELETE"),
        ("HttpPatch", "PATCH"),
        ("HttpHead", "HEAD"),
    ];

    for i in 0..method.child_count() {
        let Some(c) = method.child(i) else {
            continue;
        };
        if c.kind() != "attribute_list" {
            continue;
        }
        for j in 0..c.child_count() {
            let Some(attr) = c.child(j) else {
                continue;
            };
            if attr.kind() != "attribute" {
                continue;
            }
            let Some(name_n) = attr.child_by_field_name("name") else {
                continue;
            };
            let Some(simple) = csharp_attribute_simple_name_from_name_node(name_n, source) else {
                continue;
            };

            if simple == "Route" {
                if let Some(raw) = csharp_first_string_in_attribute(attr, source) {
                    route_attr = csharp_route_path_from_str(&raw);
                }
                continue;
            }

            if let Some((_, verb)) = VERB_ATTRS.iter().find(|(a, _)| *a == simple.as_str()) {
                csharp_push_http_verb(&mut verbs, verb);
                if let Some(raw) = csharp_first_string_in_attribute(attr, source) {
                    http_template = csharp_route_path_from_str(&raw);
                }
            }
        }
    }

    (verbs, http_template, route_attr)
}

/// Combine optional class-level route with a method template or default `/{method_name}`.
fn csharp_join_route_parts(
    class_route: Option<&str>,
    method_template: Option<&str>,
    method_name: &str,
) -> String {
    fn strip_slashes(s: &str) -> &str {
        s.trim().trim_start_matches('/').trim_end_matches('/')
    }

    let method_part = method_template
        .map(|s| s.trim())
        .filter(|s| !s.is_empty())
        .map(strip_slashes)
        .filter(|s| !s.is_empty())
        .map(|s| s.to_string())
        .unwrap_or_else(|| method_name.trim().to_string());

    let Some(base_raw) = class_route.map(str::trim).filter(|s| !s.is_empty()) else {
        let m = strip_slashes(&method_part);
        return format!("/{}", m);
    };

    let base = strip_slashes(base_raw);
    if base.is_empty() {
        return format!("/{}", strip_slashes(&method_part));
    }
    format!("/{}/{}", base, strip_slashes(&method_part))
}

/// Extract C# HTTP API endpoints from the AST using ASP.NET attribute conventions.
///
/// Returns `(http_methods, path_template, handler_method_name)` per `method_declaration`
/// that has at least one `Http*` verb, `[Route]` on the method, or a string route on a verb attribute.
fn extract_csharp_api_endpoints_from_tree(tree: &Tree, source: &str) -> Vec<(Vec<String>, String, String)> {
    let mut endpoints: Vec<(Vec<String>, String, String)> = Vec::new();
    let root = tree.root_node();

    walk_tree(root, |node| {
        if node.kind() != "method_declaration" {
            return;
        }

        let method_name = node
            .child_by_field_name("name")
            .and_then(|n| csharp_node_text(n, source))
            .or_else(|| identifier_text_from_children(node, source));

        let Some(method_name) = method_name else {
            return;
        };

        let (verbs, http_template, route_attr) = csharp_parse_method_api_attributes(node, source);

        if verbs.is_empty() && http_template.is_none() && route_attr.is_none() {
            return;
        }

        let methods_http = if verbs.is_empty() {
            vec!["ANY".to_string()]
        } else {
            verbs
        };

        let method_segment = http_template.or(route_attr);
        let class_route = csharp_enclosing_route_type_for_method(node)
            .and_then(|t| csharp_type_level_route_template(t, source));

        let path_template = csharp_join_route_parts(
            class_route.as_deref(),
            method_segment.as_deref(),
            &method_name,
        );

        endpoints.push((methods_http, path_template, method_name));
    });

    endpoints
}

/// Build a map from simple class name -> fully-qualified name for internal
/// project imports (i.e. `com.redbus.genai.*`), e.g.:
/// `com.redbus.genai.model.OrderDetail` -> `OrderDetail`.
fn build_internal_import_map(source: &str) -> HashMap<String, String> {
    let mut map = HashMap::new();
    for fqn in extract_internal_java_imports(source) {
        if let Some(simple) = fqn.rsplit('.').next() {
            map.insert(simple.to_string(), fqn.clone());
        }
    }
    map
}

/// Given a local variable declaration statement, heuristically extract a
/// mapping from variable name -> variable type simple name / FQN.
///
/// This is intentionally simple and geared towards cases like:
///     OrderDetail detail = new OrderDetail();
fn collect_local_var_types_for_method(
    method_node: Node,
    source: &str,
    package: Option<&str>,
    import_map: &HashMap<String, String>,
) -> HashMap<String, String> {
    let mut vars: HashMap<String, String> = HashMap::new();

    walk_tree(method_node, |node| {
        if node.kind() != "local_variable_declaration" {
            return;
        }

        let start = node.start_byte() as usize;
        let end = node.end_byte() as usize;
        if end > source.len() || start >= end {
            return;
        }

        let stmt = &source[start..end];
        let before_eq = stmt.split('=').next().unwrap_or("").trim();
        // Expect something like: "OrderDetail detail" or "Type var,"
        let mut parts = before_eq.split_whitespace();
        let type_part = match parts.next() {
            Some(t) => t,
            None => return,
        };
        let var_part = match parts.next() {
            Some(v) => v,
            None => return,
        };

        // Clean up generic type suffixes and package prefixes in the type.
        let type_simple = type_part
            .split('<')
            .next()
            .unwrap_or(type_part)
            .split('.')
            .last()
            .unwrap_or(type_part)
            .trim();

        // Clean up trailing punctuation from variable name.
        let var_name = var_part
            .trim_end_matches(';')
            .trim_end_matches(',')
            .trim();

        if var_name.is_empty() || type_simple.is_empty() {
            return;
        }

        // Resolve the type to an FQN using imports when possible, otherwise:
        // - fall back to wildcard imports like `com.redbus.genai.utils.*`
        // - then to the current package (if any)
        // - finally to the simple name.
        let fqn = if let Some(import_fqn) = import_map.get(type_simple) {
            import_fqn.clone()
        } else if let Some(pkg_prefix) = import_map
            .values()
            .find(|v| v.ends_with(".*"))
        {
            let base = pkg_prefix.trim_end_matches(".*");
            format!("{base}.{type_simple}")
        } else if let Some(pkg) = package {
            format!("{pkg}.{type_simple}")
        } else {
            type_simple.to_string()
        };

        vars.insert(var_name.to_string(), fqn);
    });

    vars
}

/// Collect all identifier texts under a given subtree. This is used for
/// heuristically separating the receiver variable from the invoked method
/// name inside a `method_invocation`.
fn collect_identifiers(node: Node, source: &str, out: &mut Vec<String>) {
    walk_tree(node, |n| {
        if n.kind() == "identifier" {
            let start = n.start_byte() as usize;
            let end = n.end_byte() as usize;
            if end <= source.len() && start < end {
                out.push(source[start..end].to_string());
            }
        }
    });
}

/// Extract a basic Java call graph: caller function FQN -> callee function FQN.
///
/// This focuses on:
/// - Building a caller FQN for each `method_declaration`.
/// - Within that method's subtree, discovering `method_invocation` nodes and
///   attempting to resolve:
///     - Calls on local variables to the variable's declared type (using
///       imports + package to build a best-effort FQN).
///     - Otherwise, falling back to treating the call as intra-class.
fn extract_java_calls(
    tree: &Tree,
    source: &str,
    package: Option<&str>,
) -> Vec<(String, String)> {
    let mut calls: Vec<(String, String)> = Vec::new();
    let root = tree.root_node();

    // Pre-compute a simple mapping of imported type simple names to their FQNs
    // for internal project imports. This lets us resolve variables like
    // `OrderDetail detail = new OrderDetail();` to `com.redbus.genai.model.OrderDetail`.
    let import_map = build_internal_import_map(source);

    walk_tree(root, |node| {
        if node.kind() != "method_declaration" {
            return;
        }

        // Determine the caller method FQN using the same logic as in
        // `extract_java_symbols`.
        let method_name = match identifier_text_from_children(node, source) {
            Some(name) => name,
            None => return,
        };

        // Find the nearest enclosing class / interface to build the class FQN.
        let mut parent = node.parent();
        let mut class_fqn: Option<String> = None;
        while let Some(p) = parent {
            let pk = p.kind();
            if pk == "class_declaration" || pk == "interface_declaration" {
                if let Some(class_name) = identifier_text_from_children(p, source) {
                    let full = if let Some(pkg) = package {
                        format!("{pkg}.{class_name}")
                    } else {
                        class_name
                    };
                    class_fqn = Some(full);
                }
                break;
            }
            parent = p.parent();
        }

        let caller_fqn = if let Some(ref cls) = class_fqn {
            format!("{cls}.{}", method_name)
        } else if let Some(pkg) = package {
            format!("{pkg}.{}", method_name)
        } else {
            method_name.clone()
        };

        // Collect local variable types inside this method so that we can
        // resolve calls like `detail.setAmenities(...)` to the type of
        // `detail` (e.g. `com.redbus.genai.model.OrderDetail`).
        let local_var_types =
            collect_local_var_types_for_method(node, source, package, &import_map);

        // Walk the body of this method and capture method_invocation nodes.
        walk_tree(node, |child| {
            if child.kind() != "method_invocation" {
                return;
            }

            // Resolve the invoked method name. Prefer the `name` field from the
            // Tree-Sitter Java grammar; fall back to the older heuristic if
            // that is not available.
            let callee_name = if let Some(name_node) = child.child_by_field_name("name") {
                let start = name_node.start_byte() as usize;
                let end = name_node.end_byte() as usize;
                if end <= source.len() && start < end {
                    source[start..end].to_string()
                } else {
                    match identifier_text_from_children(child, source) {
                        Some(name) => name,
                        None => return,
                    }
                }
            } else {
                match identifier_text_from_children(child, source) {
                    Some(name) => name,
                    None => return,
                }
            };

            // Try to resolve the receiver variable (e.g. `detail` in
            // `detail.setAmenities(...)`) to its declared type FQN using the
            // local variable map. We only consider the `object` field of the
            // method invocation (the receiver expression), not nested
            // identifiers inside the arguments.
            let mut receiver_type_fqn: Option<String> = None;
            if let Some(object_node) = child.child_by_field_name("object") {
                let mut recv_idents: Vec<String> = Vec::new();
                collect_identifiers(object_node, source, &mut recv_idents);

                // 1) First, try to resolve the receiver as a local variable
                //    (e.g. `detail.setAmenities(...)` where `detail` is a
                //    local of type `OrderDetail`).
                for ident in &recv_idents {
                    if let Some(ty) = local_var_types.get(ident) {
                        receiver_type_fqn = Some(ty.clone());
                        break;
                    }
                }

                // 2) If that fails, fall back to treating the receiver as a
                //    type name coming from imports or the current package,
                //    which lets us resolve static calls like:
                //    `OrderDetailsFetcher.getAllOrderDetailsOfCustomer(...)`.
                if receiver_type_fqn.is_none() {
                    if let Some(first_ident) = recv_idents.first() {
                        if let Some(import_fqn) = import_map.get(first_ident) {
                            receiver_type_fqn = Some(import_fqn.clone());
                        } else if let Some(pkg_prefix) = import_map
                            .values()
                            .find(|v| v.ends_with(".*"))
                        {
                            let base = pkg_prefix.trim_end_matches(".*");
                            receiver_type_fqn =
                                Some(format!("{base}.{first_ident}"));
                        } else if let Some(pkg) = package {
                            receiver_type_fqn =
                                Some(format!("{pkg}.{first_ident}"));
                        }
                    }
                }
            }

            let callee_fqn = if let Some(ref recv_ty) = receiver_type_fqn {
                format!("{recv_ty}.{}", callee_name)
            } else if let Some(ref cls) = class_fqn {
                format!("{cls}.{}", callee_name)
            } else if let Some(pkg) = package {
                format!("{pkg}.{}", callee_name)
            } else {
                callee_name.clone()
            };

            calls.push((caller_fqn.clone(), callee_fqn));
        });
    });

    calls
}

// --- Non-Java (Python / JS / TS / TSX / Rust) graph helpers -------------------------------------

fn node_text_slice(n: Node, source: &str) -> Option<String> {
    let s = n.start_byte() as usize;
    let e = (n.end_byte() as usize).min(source.len());
    (s < e).then(|| source[s..e].to_string())
}

fn non_java_file_scoped_fqn(file_path: &str, logical_name: &str) -> String {
    format!("{file_path}::{logical_name}")
}

/// Short name and nesting depth for resolving intra-file calls to the best FQN.
fn non_java_short_name_and_depth(language: LanguageId, logical: &str) -> (String, usize) {
    match language {
        LanguageId::Rust => {
            let short = logical
                .rsplit("::")
                .next()
                .unwrap_or(logical)
                .to_string();
            (short, logical.matches("::").count())
        }
        _ => {
            let short = logical
                .rsplit_once('.')
                .map(|(_, s)| s)
                .unwrap_or(logical)
                .to_string();
            (short, logical.matches('.').count())
        }
    }
}

fn rust_inside_impl(node: Node) -> bool {
    let mut cur = node.parent();
    while let Some(p) = cur {
        if p.kind() == "impl_item" {
            return true;
        }
        cur = p.parent();
    }
    false
}

fn rust_enclosing_mod_prefixes(fn_node: Node, source: &str) -> Vec<String> {
    let mut prefixes = Vec::new();
    let mut cur = fn_node.parent();
    while let Some(p) = cur {
        if p.kind() == "mod_item" {
            if let Some(name_n) = p.child_by_field_name("name") {
                if let Some(name) = node_text_slice(name_n, source) {
                    let name = name.trim();
                    if !name.is_empty() {
                        prefixes.insert(0, name.to_string());
                    }
                }
            }
        }
        cur = p.parent();
    }
    prefixes
}

fn rust_function_logical_name(fn_node: Node, source: &str) -> Option<String> {
    let name = rust_function_name(fn_node, source)?;
    let prefixes = rust_enclosing_mod_prefixes(fn_node, source);
    Some(if prefixes.is_empty() {
        name
    } else {
        format!("{}::{}", prefixes.join("::"), name)
    })
}

fn rust_innermost_enclosing_function(call: Node) -> Option<Node> {
    let mut cur = call.parent();
    while let Some(p) = cur {
        if p.kind() == "function_item" && !rust_inside_impl(p) {
            return Some(p);
        }
        cur = p.parent();
    }
    None
}

fn extract_rust_graph_symbols(tree: &Tree, source: &str, file_path: &str) -> Vec<FunctionSymbol> {
    let mut out = Vec::new();
    let mut seen = HashSet::new();
    walk_tree(tree.root_node(), |node| {
        if node.kind() != "function_item" || rust_inside_impl(node) {
            return;
        }
        let Some(logical) = rust_function_logical_name(node, source) else {
            return;
        };
        let fqn = non_java_file_scoped_fqn(file_path, &logical);
        if !seen.insert(fqn.clone()) {
            return;
        }
        let name = rust_function_name(node, source).unwrap_or_default();
        out.push(FunctionSymbol {
            name,
            fqn,
            class_fqn: None,
            return_type: None,
            param_types: Vec::new(),
            param_count: 0,
            modifiers: Vec::new(),
            is_pointer_receiver: None,
        });
    });
    out
}

fn extract_rust_intrafile_calls(
    tree: &Tree,
    source: &str,
    file_path: &str,
    name_to_fqn: &HashMap<String, String>,
) -> Vec<(String, String)> {
    let mut calls = Vec::new();
    walk_tree(tree.root_node(), |inner| {
        if inner.kind() != "call_expression" {
            return;
        }
        let Some(encl) = rust_innermost_enclosing_function(inner) else {
            return;
        };
        let Some(logical) = rust_function_logical_name(encl, source) else {
            return;
        };
        let caller_fqn = non_java_file_scoped_fqn(file_path, &logical);
        let Some(func_n) = inner.child_by_field_name("function") else {
            return;
        };
        if func_n.kind() != "identifier" {
            return;
        }
        let Some(callee_name) = node_text_slice(func_n, source) else {
            return;
        };
        let callee_name = callee_name.trim();
        if let Some(callee_fqn) = name_to_fqn.get(callee_name) {
            calls.push((caller_fqn, callee_fqn.clone()));
        }
    });
    calls
}

fn rust_use_path_segments_from_node(node: Node, source: &str) -> Option<Vec<String>> {
    let text = node_text_slice(node, source)?;
    let text = text.split('{').next()?.trim();
    let text = text.trim_end_matches(';').trim();
    if text.is_empty() {
        return None;
    }
    let segs: Vec<String> = text
        .split("::")
        .map(|s| s.trim().to_string())
        .filter(|s| !s.is_empty() && s != "*" && s != "as")
        .collect();
    if segs.is_empty() {
        None
    } else {
        Some(segs)
    }
}

fn extract_rust_use_paths(tree: &Tree, source: &str) -> Vec<Vec<String>> {
    let mut out = Vec::new();
    walk_tree(tree.root_node(), |node| {
        if node.kind() != "use_declaration" {
            return;
        }
        walk_tree(node, |inner| {
            if inner.kind() != "scoped_identifier" && inner.kind() != "use_tree" {
                return;
            }
            if let Some(segs) = rust_use_path_segments_from_node(inner, source) {
                if !segs.is_empty() && !out.contains(&segs) {
                    out.push(segs);
                }
            }
        });
    });
    out
}

fn rust_file_to_module_path(file_path: &str) -> Vec<String> {
    let p = file_path.replace('\\', "/");
    let p = p.strip_prefix("src/").unwrap_or(p.as_str());
    if p == "lib.rs" || p == "main.rs" {
        return Vec::new();
    }
    if let Some(dir) = p.strip_suffix("/mod.rs") {
        if dir.is_empty() {
            return Vec::new();
        }
        return dir.split('/').map(String::from).collect();
    }
    if let Some(stem) = p.strip_suffix(".rs") {
        if stem.is_empty() {
            return Vec::new();
        }
        return stem.split('/').map(String::from).collect();
    }
    Vec::new()
}

fn rust_module_path_to_file_candidates(segments: &[String]) -> Vec<String> {
    if segments.is_empty() {
        return vec!["src/lib.rs".to_string(), "src/main.rs".to_string()];
    }
    let joined = segments.join("/");
    vec![
        format!("src/{joined}.rs"),
        format!("src/{joined}/mod.rs"),
    ]
}

fn resolve_rust_use_to_known_file(
    use_segments: &[String],
    current_file: &str,
    known_paths: &HashSet<String>,
) -> Option<String> {
    if use_segments.is_empty() {
        return None;
    }
    let mut mod_path = rust_file_to_module_path(current_file);
    let mut i = 0usize;
    match use_segments[0].as_str() {
        "crate" => {
            i = 1;
            mod_path.clear();
        }
        "super" => {
            i = 1;
            if !mod_path.is_empty() {
                mod_path.pop();
            }
        }
        "self" => {
            i = 1;
        }
        _ => {}
    }
    let rest: Vec<String> = use_segments[i..].to_vec();
    for len in (0..=rest.len()).rev() {
        let mut target = mod_path.clone();
        target.extend(rest[..len].iter().cloned());
        for cand in rust_module_path_to_file_candidates(&target) {
            if known_paths.contains(&cand) {
                return Some(cand);
            }
        }
    }
    None
}

fn extract_non_java_function_symbols(
    file: &ParsedFile,
    source: &str,
    file_path: &str,
) -> Vec<FunctionSymbol> {
    match file.language {
        LanguageId::Rust => extract_rust_graph_symbols(&file.tree, source, file_path),
        LanguageId::Python => extract_python_graph_symbols(&file.tree, source, file_path),
        LanguageId::JavaScript | LanguageId::TypeScript | LanguageId::Tsx => {
            extract_js_ts_graph_symbols(&file.tree, source, file_path, file.language)
        }
        _ => Vec::new(),
    }
}

fn extract_python_parse_warnings(tree: &Tree, source: &str) -> Vec<(usize, usize, String)> {
    let mut out = Vec::new();
    walk_tree(tree.root_node(), |node| {
        if node.kind() == "ERROR" || node.is_missing() {
            let pos = node.start_position();
            let s = node.start_byte() as usize;
            let e = (node.end_byte() as usize).min(source.len());
            let snippet = if s < e {
                source[s..e]
                    .chars()
                    .take(120)
                    .collect::<String>()
                    .replace('\n', " ")
            } else {
                String::new()
            };
            out.push((pos.row + 1, pos.column + 1, snippet));
        }
    });
    out
}

fn extract_js_ts_parse_warnings(tree: &Tree, source: &str) -> Vec<(usize, usize, String)> {
    extract_python_parse_warnings(tree, source)
}

fn python_node_inside_class(mut node: Node) -> bool {
    while let Some(p) = node.parent() {
        if p.kind() == "class_definition" {
            return true;
        }
        node = p;
    }
    false
}

fn python_function_definition_name(fn_node: Node, source: &str) -> Option<String> {
    fn_node
        .child_by_field_name("name")
        .and_then(|n| node_text_slice(n, source))
        .map(|s| s.trim().to_string())
        .filter(|s| !s.is_empty())
}

fn python_enclosing_function_prefixes(fn_node: Node, source: &str) -> Vec<String> {
    let mut prefixes = Vec::new();
    let mut cur = fn_node.parent();
    while let Some(p) = cur {
        if p.kind() == "function_definition" && !python_node_inside_class(p) {
            if let Some(n) = python_function_definition_name(p, source) {
                prefixes.insert(0, n);
            }
        }
        cur = p.parent();
    }
    prefixes
}

fn python_function_logical_name(fn_node: Node, source: &str) -> Option<String> {
    let name = python_function_definition_name(fn_node, source)?;
    let prefixes = python_enclosing_function_prefixes(fn_node, source);
    Some(if prefixes.is_empty() {
        name
    } else {
        format!("{}.{}", prefixes.join("."), name)
    })
}

fn extract_python_graph_symbols(tree: &Tree, source: &str, file_path: &str) -> Vec<FunctionSymbol> {
    let mut out = Vec::new();
    let mut seen = HashSet::new();
    walk_tree(tree.root_node(), |node| {
        if node.kind() != "function_definition" {
            return;
        }
        if python_node_inside_class(node) {
            return;
        }
        let Some(logical) = python_function_logical_name(node, source) else {
            return;
        };
        let fqn = non_java_file_scoped_fqn(file_path, &logical);
        if !seen.insert(fqn.clone()) {
            return;
        }
        let name = python_function_definition_name(node, source).unwrap_or_default();
        out.push(FunctionSymbol {
            name,
            fqn,
            class_fqn: None,
            return_type: None,
            param_types: Vec::new(),
            param_count: 0,
            modifiers: Vec::new(),
            is_pointer_receiver: None,
        });
    });
    out
}

fn python_innermost_enclosing_function(call: Node) -> Option<Node> {
    let mut cur = call.parent();
    while let Some(p) = cur {
        if p.kind() == "function_definition" && !python_node_inside_class(p) {
            return Some(p);
        }
        cur = p.parent();
    }
    None
}

fn extract_python_intrafile_calls(
    tree: &Tree,
    source: &str,
    file_path: &str,
    name_to_fqn: &HashMap<String, String>,
) -> Vec<(String, String)> {
    let mut calls = Vec::new();
    walk_tree(tree.root_node(), |inner| {
        if inner.kind() != "call" {
            return;
        }
        let Some(encl) = python_innermost_enclosing_function(inner) else {
            return;
        };
        let Some(logical) = python_function_logical_name(encl, source) else {
            return;
        };
        let caller_fqn = non_java_file_scoped_fqn(file_path, &logical);
        let Some(func_n) = inner.child_by_field_name("function") else {
            return;
        };
        if func_n.kind() != "identifier" {
            return;
        }
        let Some(callee_name) = node_text_slice(func_n, source) else {
            return;
        };
        let callee_name = callee_name.trim();
        if let Some(callee_fqn) = name_to_fqn.get(callee_name) {
            calls.push((caller_fqn, callee_fqn.clone()));
        }
    });
    calls
}

fn extract_python_import_modules(tree: &Tree, source: &str) -> Vec<String> {
    let mut out = Vec::new();
    walk_tree(tree.root_node(), |node| match node.kind() {
        "import_from_statement" => {
            if let Some(mod_n) = node.child_by_field_name("module_name") {
                let t = node_text_slice(mod_n, source).unwrap_or_default();
                let t = t.trim();
                if !t.is_empty() && t != "." && !t.starts_with('.') {
                    out.push(t.to_string());
                }
            }
        }
        "import_statement" => {
            let mut c = node.walk();
            if !c.goto_first_child() {
                return;
            }
            loop {
                let ch = c.node();
                match ch.kind() {
                    "dotted_name" => {
                        if let Some(t) = node_text_slice(ch, source) {
                            let t = t.trim();
                            if !t.is_empty() {
                                out.push(t.to_string());
                            }
                        }
                    }
                    "aliased_import" => {
                        if let Some(name_n) = ch.child_by_field_name("name") {
                            if name_n.kind() == "dotted_name" {
                                if let Some(t) = node_text_slice(name_n, source) {
                                    let t = t.trim();
                                    if !t.is_empty() {
                                        out.push(t.to_string());
                                    }
                                }
                            }
                        }
                    }
                    _ => {}
                }
                if !c.goto_next_sibling() {
                    break;
                }
            }
        }
        _ => {}
    });
    out.sort();
    out.dedup();
    out
}

fn resolve_python_import_to_known_file(
    module_path: &str,
    known_paths: &HashSet<String>,
) -> Option<String> {
    let norm = module_path.trim();
    if norm.is_empty() {
        return None;
    }
    let needle = norm.replace('.', "/");
    known_paths
        .iter()
        .filter(|p| {
            let pn = p.replace('\\', "/");
            pn.ends_with(".py") && pn.contains(needle.as_str())
        })
        .min_by_key(|p| p.len())
        .cloned()
}

fn js_inside_class(mut node: Node) -> bool {
    while let Some(p) = node.parent() {
        if p.kind() == "class_declaration" {
            return true;
        }
        node = p;
    }
    false
}

fn js_function_declaration_name(node: Node, source: &str) -> Option<String> {
    node.child_by_field_name("name")
        .and_then(|n| node_text_slice(n, source))
        .map(|s| s.trim().to_string())
        .filter(|s| !s.is_empty())
}

fn js_nested_function_declaration_prefix(fn_node: Node, source: &str, self_name: &str) -> String {
    let mut prefixes = Vec::new();
    let mut cur = fn_node.parent();
    while let Some(p) = cur {
        if p.kind() == "function_declaration" && !js_inside_class(p) {
            if let Some(n) = js_function_declaration_name(p, source) {
                prefixes.insert(0, n);
            }
        }
        cur = p.parent();
    }
    if prefixes.is_empty() {
        self_name.to_string()
    } else {
        format!("{}.{}", prefixes.join("."), self_name)
    }
}

fn js_prefix_from_ancestors_for_expr(expr_node: Node, source: &str, var_name: &str) -> String {
    let mut prefixes = Vec::new();
    let mut cur = expr_node.parent();
    while let Some(p) = cur {
        if p.kind() == "function_declaration" && !js_inside_class(p) {
            if let Some(n) = js_function_declaration_name(p, source) {
                prefixes.insert(0, n);
            }
        }
        cur = p.parent();
    }
    if prefixes.is_empty() {
        var_name.to_string()
    } else {
        format!("{}.{}", prefixes.join("."), var_name)
    }
}

fn js_class_declaration_name_from(class_node: Node, source: &str) -> Option<String> {
    class_node
        .child_by_field_name("name")
        .and_then(|n| node_text_slice(n, source))
        .map(|s| s.trim().to_string())
        .filter(|s| !s.is_empty())
}

fn js_enclosing_class_declaration_name(start: Node, source: &str) -> Option<String> {
    let mut cur = start.parent();
    while let Some(p) = cur {
        if p.kind() == "class_declaration" {
            return js_class_declaration_name_from(p, source);
        }
        cur = p.parent();
    }
    None
}

fn js_property_name_text(method_node: Node, source: &str) -> Option<String> {
    let name_node = method_node
        .child_by_field_name("name")
        .or_else(|| method_node.child_by_field_name("property"))?;
    match name_node.kind() {
        "property_identifier" | "identifier" | "private_property_identifier" => {
            node_text_slice(name_node, source)
        }
        _ => None,
    }
    .map(|s| s.trim().to_string())
    .filter(|s| !s.is_empty())
}

fn is_js_ts_class_member_fn(kind: &str) -> bool {
    matches!(
        kind,
        "method_definition"
            | "field_definition"
            | "public_field_definition"
            | "private_field_definition"
            | "protected_field_definition"
    )
}

fn js_ts_string_inner(spec: &str) -> String {
    let t = spec.trim();
    if t.len() >= 2 {
        let bytes = t.as_bytes();
        let q = bytes[0];
        if (q == b'"' || q == b'\'') && bytes[t.len() - 1] == q {
            return t[1..t.len() - 1].to_string();
        }
    }
    t.to_string()
}

fn extract_js_ts_import_specifiers(tree: &Tree, source: &str) -> Vec<String> {
    let mut out = Vec::new();
    walk_tree(tree.root_node(), |node| {
        if node.kind() != "import_statement" && node.kind() != "export_statement" {
            return;
        }
        if let Some(src) = node.child_by_field_name("source") {
            if src.kind() == "string" {
                if let Some(raw) = node_text_slice(src, source) {
                    let inner = js_ts_string_inner(&raw);
                    if !inner.is_empty() {
                        out.push(inner);
                    }
                }
            }
        }
    });
    out.sort();
    out.dedup();
    out
}

/// Normalize a logical path to forward slashes, collapse `.` / `..`, and preserve a leading `/`.
fn normalized_logical_path(path: &Path) -> String {
    use std::path::Component;
    let mut parts: Vec<String> = Vec::new();
    let mut starts_root = false;
    for c in path.components() {
        match c {
            Component::RootDir => starts_root = true,
            Component::Prefix(_) => {}
            Component::CurDir => {}
            Component::Normal(s) => parts.push(s.to_string_lossy().into_owned()),
            Component::ParentDir => {
                parts.pop();
            }
        }
    }
    let s = parts.join("/");
    if starts_root {
        format!("/{s}")
    } else {
        s
    }
}

fn resolve_js_ts_import_to_known_file(
    spec: &str,
    current_file: &str,
    known_paths: &HashSet<String>,
) -> Option<String> {
    let spec = spec.trim();
    if spec.is_empty() {
        return None;
    }
    if spec.starts_with('@') {
        return None;
    }

    let try_extensions = |base: &str| -> Option<String> {
        let base = base.replace('\\', "/");
        for ext in ["", ".ts", ".tsx", ".js", ".jsx"] {
            let cand = format!("{base}{ext}");
            if known_paths.contains(&cand) {
                return Some(cand);
            }
        }
        for ext in [".ts", ".tsx", ".js", ".jsx"] {
            let cand = format!("{base}/index{ext}");
            if known_paths.contains(&cand) {
                return Some(cand);
            }
        }
        None
    };

    if spec.starts_with('.') {
        let base = Path::new(current_file).parent()?;
        let joined = base.join(spec);
        let normalized = normalized_logical_path(&joined);
        return try_extensions(&normalized);
    }

    let needle = spec.replace('\\', "/");
    known_paths
        .iter()
        .filter(|p| {
            let pn = p.replace('\\', "/");
            (pn.ends_with(".ts")
                || pn.ends_with(".tsx")
                || pn.ends_with(".js")
                || pn.ends_with(".jsx"))
                && pn.contains(needle.as_str())
        })
        .min_by_key(|p| p.len())
        .cloned()
}

fn extract_js_ts_graph_symbols(
    tree: &Tree,
    source: &str,
    file_path: &str,
    language: LanguageId,
) -> Vec<FunctionSymbol> {
    let _ = language;
    let mut out = Vec::new();
    let mut seen = HashSet::new();
    let root = tree.root_node();

    let mut push = |logical: String, name: String| {
        let fqn = non_java_file_scoped_fqn(file_path, &logical);
        if seen.insert(fqn.clone()) {
            out.push(FunctionSymbol {
                name,
                fqn,
                class_fqn: None,
                return_type: None,
                param_types: Vec::new(),
                param_count: 0,
                modifiers: Vec::new(),
                is_pointer_receiver: None,
            });
        }
    };

    walk_tree(root, |node| {
        let kind = node.kind();
        if kind == "function_declaration" {
            if js_inside_class(node) {
                return;
            }
            let Some(nm) = js_function_declaration_name(node, source) else {
                return;
            };
            let logical = js_nested_function_declaration_prefix(node, source, &nm);
            push(logical, nm);
            return;
        }

        if is_js_ts_class_member_fn(kind) {
            let Some(meth) = js_property_name_text(node, source) else {
                return;
            };
            let cls = js_enclosing_class_declaration_name(node, source)
                .unwrap_or_else(|| "anonymous_class".to_string());
            let logical = format!("{cls}.{meth}");
            push(logical, meth);
            return;
        }

        if kind == "variable_declarator" {
            let Some(val) = node.child_by_field_name("value") else {
                return;
            };
            if !matches!(val.kind(), "arrow_function" | "function_expression") {
                return;
            }
            let Some(name_n) = node.child_by_field_name("name") else {
                return;
            };
            if name_n.kind() != "identifier" {
                return;
            }
            let Some(var_name) = node_text_slice(name_n, source) else {
                return;
            };
            let var_name = var_name.trim().to_string();
            if var_name.is_empty() {
                return;
            }
            if js_inside_class(node) {
                let cls = js_enclosing_class_declaration_name(node, source)
                    .unwrap_or_else(|| "anonymous_class".to_string());
                let logical = format!("{cls}.{var_name}");
                push(logical, var_name);
            } else {
                let logical = js_prefix_from_ancestors_for_expr(val, source, &var_name);
                push(logical, var_name);
            }
        }
    });

    out
}

fn js_ts_innermost_enclosing_logical(call: Node, source: &str) -> Option<String> {
    let mut cur = call.parent();
    while let Some(p) = cur {
        match p.kind() {
            "function_declaration" => {
                if js_inside_class(p) {
                    cur = p.parent();
                    continue;
                }
                let nm = js_function_declaration_name(p, source)?;
                return Some(js_nested_function_declaration_prefix(p, source, &nm));
            }
            k if is_js_ts_class_member_fn(k) => {
                let meth = js_property_name_text(p, source)?;
                let cls = js_enclosing_class_declaration_name(p, source)
                    .unwrap_or_else(|| "anonymous_class".to_string());
                return Some(format!("{cls}.{meth}"));
            }
            "arrow_function" | "function_expression" => {
                let mut up = Some(p);
                while let Some(x) = up {
                    if x.kind() == "variable_declarator" {
                        let name_n = x.child_by_field_name("name")?;
                        if name_n.kind() != "identifier" {
                            return None;
                        }
                        let vn = node_text_slice(name_n, source)?;
                        let vn = vn.trim();
                        if vn.is_empty() {
                            return None;
                        }
                        return Some(js_prefix_from_ancestors_for_expr(p, source, vn));
                    }
                    up = x.parent();
                }
            }
            _ => {}
        }
        cur = p.parent();
    }
    None
}

fn extract_js_ts_intrafile_calls(
    tree: &Tree,
    source: &str,
    file_path: &str,
    language: LanguageId,
    name_to_fqn: &HashMap<String, String>,
) -> Vec<(String, String)> {
    let _ = language;
    let mut calls = Vec::new();
    walk_tree(tree.root_node(), |inner| {
        if inner.kind() != "call_expression" {
            return;
        }
        let Some(logical) = js_ts_innermost_enclosing_logical(inner, source) else {
            return;
        };
        let caller_fqn = non_java_file_scoped_fqn(file_path, &logical);
        let Some(func_n) = inner.child_by_field_name("function") else {
            return;
        };
        if func_n.kind() != "identifier" {
            return;
        }
        let Some(callee_name) = node_text_slice(func_n, source) else {
            return;
        };
        let callee_name = callee_name.trim();
        if let Some(callee_fqn) = name_to_fqn.get(callee_name) {
            calls.push((caller_fqn, callee_fqn.clone()));
        }
    });
    calls
}

/// Extract Java Spring Framework API endpoints from source code.
///
/// Detects annotations like:
/// - @GetMapping("/path"), @PostMapping("/path"), etc.
/// - @RequestMapping(value = "/path", method = RequestMethod.GET)
/// - Class-level @RequestMapping combined with method-level mappings
fn extract_java_spring_endpoints(source: &str) -> Vec<(Vec<String>, String, String)> {
    let mut endpoints: Vec<(Vec<String>, String, String)> = Vec::new();
    let mut class_base_path: Option<String> = None;
    let mut pending_methods: Vec<String> = Vec::new();
    let mut pending_path: Option<String> = None;

    for line in source.lines() {
        let trimmed = line.trim();

        // Detect class-level @RequestMapping for base path
        if trimmed.starts_with("@RequestMapping") && !trimmed.contains("method") {
            if let Some(path) = extract_java_annotation_path(trimmed) {
                class_base_path = Some(path);
            }
            continue;
        }

        // Detect @RestController or @Controller (indicates this is an API class)
        if trimmed.starts_with("@RestController") || trimmed.starts_with("@Controller") {
            continue;
        }

        // Method-level annotations
        if trimmed.starts_with('@') {
            for (attr, verb) in [
                ("@GetMapping", "GET"),
                ("@PostMapping", "POST"),
                ("@PutMapping", "PUT"),
                ("@DeleteMapping", "DELETE"),
                ("@PatchMapping", "PATCH"),
            ] {
                if trimmed.starts_with(attr) {
                    pending_methods.push(verb.to_string());
                    if let Some(path) = extract_java_annotation_path(trimmed) {
                        pending_path = Some(path);
                    } else {
                        pending_path = Some("/".to_string());
                    }
                }
            }

            // Handle @RequestMapping with method specification
            if trimmed.starts_with("@RequestMapping") {
                if let Some(path) = extract_java_annotation_path(trimmed) {
                    pending_path = Some(path);
                }
                // Extract method if specified
                if trimmed.contains("RequestMethod.GET") {
                    pending_methods.push("GET".to_string());
                } else if trimmed.contains("RequestMethod.POST") {
                    pending_methods.push("POST".to_string());
                } else if trimmed.contains("RequestMethod.PUT") {
                    pending_methods.push("PUT".to_string());
                } else if trimmed.contains("RequestMethod.DELETE") {
                    pending_methods.push("DELETE".to_string());
                } else if pending_path.is_some() && pending_methods.is_empty() {
                    pending_methods.push("ANY".to_string());
                }
            }
            continue;
        }

        // Method declaration line
        if (trimmed.starts_with("public ")
            || trimmed.starts_with("private ")
            || trimmed.starts_with("protected "))
            && trimmed.contains('(')
            && !pending_methods.is_empty()
        {
            let before_paren = match trimmed.split_once('(') {
                Some((before, _)) => before,
                None => continue,
            };
            let mut last = None;
            for p in before_paren.split_whitespace() {
                last = Some(p);
            }
            let method_name = match last {
                Some(name) => name.trim().to_string(),
                None => continue,
            };

            let path_template = if let Some(ref base) = class_base_path {
                let method_path = pending_path.clone().unwrap_or_else(|| "/".to_string());
                if method_path.starts_with('/') {
                    format!("{}{}", base.trim_end_matches('/'), method_path)
                } else {
                    format!("{}/{}", base.trim_end_matches('/'), method_path)
                }
            } else {
                pending_path.clone().unwrap_or_else(|| format!("/{}", method_name))
            };

            endpoints.push((pending_methods.clone(), path_template, method_name));

            pending_methods.clear();
            pending_path = None;
        }
    }

    endpoints
}

/// Extract path from Java annotation like @GetMapping("/path") or @RequestMapping(value = "/path")
fn extract_java_annotation_path(attr_line: &str) -> Option<String> {
    // Try simple format: @GetMapping("/path")
    if let Some(start) = attr_line.find('"') {
        let rest = &attr_line[start + 1..];
        if let Some(end) = rest.find('"') {
            let path = &rest[..end];
            if !path.is_empty() {
                return Some(path.to_string());
            }
        }
    }
    None
}

/// Extract USES_CLASS relationships from Java source.
///
/// This detects:
/// - Field declarations with class types
/// - Local variable declarations with class types
/// - Method parameter types
/// - Return types
/// - new ClassName() instantiations
fn extract_java_used_classes(
    tree: &Tree,
    source: &str,
    package: Option<&str>,
) -> Vec<(String, String)> {
    let mut uses: Vec<(String, String)> = Vec::new();
    let root = tree.root_node();
    let import_map = build_internal_import_map(source);

    walk_tree(root, |node| {
        if node.kind() != "method_declaration" {
            return;
        }

        let method_name = match identifier_text_from_children(node, source) {
            Some(name) => name,
            None => return,
        };

        // Find enclosing class
        let mut parent = node.parent();
        let mut class_fqn: Option<String> = None;
        while let Some(p) = parent {
            let pk = p.kind();
            if pk == "class_declaration" || pk == "interface_declaration" {
                if let Some(class_name) = identifier_text_from_children(p, source) {
                    let full = if let Some(pkg) = package {
                        format!("{pkg}.{class_name}")
                    } else {
                        class_name
                    };
                    class_fqn = Some(full);
                }
                break;
            }
            parent = p.parent();
        }

        let func_fqn = if let Some(ref cls) = class_fqn {
            format!("{cls}.{}", method_name)
        } else if let Some(pkg) = package {
            format!("{pkg}.{}", method_name)
        } else {
            method_name.clone()
        };

        // Collect type references inside this method
        walk_tree(node, |child| {
            let kind = child.kind();

            // Look for type identifiers in various contexts
            if kind == "type_identifier" || kind == "object_creation_expression" {
                let type_name = if kind == "object_creation_expression" {
                    // Extract type from "new ClassName()"
                    child.child_by_field_name("type")
                        .and_then(|t| {
                            let start = t.start_byte() as usize;
                            let end = t.end_byte() as usize;
                            if end <= source.len() && start < end {
                                Some(source[start..end].to_string())
                            } else {
                                None
                            }
                        })
                } else {
                    let start = child.start_byte() as usize;
                    let end = child.end_byte() as usize;
                    if end <= source.len() && start < end {
                        Some(source[start..end].to_string())
                    } else {
                        None
                    }
                };

                if let Some(type_name) = type_name {
                    // Skip primitive types and common Java types
                    if is_java_primitive_or_builtin(&type_name) {
                        return;
                    }

                    // Resolve to FQN
                    let used_class_fqn = if let Some(fqn) = import_map.get(&type_name) {
                        fqn.clone()
                    } else if let Some(pkg) = package {
                        format!("{pkg}.{type_name}")
                    } else {
                        type_name
                    };

                    uses.push((func_fqn.clone(), used_class_fqn));
                }
            }
        });
    });

    uses
}

/// Check if a type name is a Java primitive or common built-in type
fn is_java_primitive_or_builtin(name: &str) -> bool {
    matches!(
        name,
        "int" | "long" | "short" | "byte" | "float" | "double" | "boolean" | "char" | "void"
            | "String" | "Integer" | "Long" | "Short" | "Byte" | "Float" | "Double" | "Boolean"
            | "Character" | "Object" | "Class" | "Void"
            | "List" | "ArrayList" | "Map" | "HashMap" | "Set" | "HashSet"
            | "Optional" | "Collection" | "Iterator"
    )
}

struct GoCallGraphEdges {
    calls_function: Vec<(String, String)>,
    uses_class: Vec<(String, String)>,
    class_uses_class: Vec<(String, String)>,
}

fn collect_go_call_graph_edges(
    tree: &Tree,
    source: &str,
    package_name: Option<&str>,
) -> GoCallGraphEdges {
    let mut calls_function = extract_go_calls(tree, source, package_name);
    calls_function.extend(extract_go_goroutine_calls(tree, source, package_name));
    GoCallGraphEdges {
        calls_function,
        uses_class: extract_go_used_types(tree, source, package_name),
        class_uses_class: extract_go_embedding(tree, source, package_name),
    }
}

fn apply_go_call_graph_to_ir(accumulator: &mut IrEdgeAccumulator, edges: GoCallGraphEdges) {
    for (caller, callee) in edges.calls_function {
        accumulator.calls_function.insert((caller, callee));
    }
    for (fn_fqn, struct_fqn) in edges.uses_class {
        accumulator.uses_class.insert((fn_fqn, struct_fqn));
    }
    for (derived, base) in edges.class_uses_class {
        accumulator.class_uses_class.insert((derived, base));
    }
}

fn apply_go_call_graph_to_batch(accumulator: &mut BatchAccumulator, edges: GoCallGraphEdges) {
    for (caller, callee) in edges.calls_function {
        accumulator.add_calls_function(caller, callee);
    }
    for (fn_fqn, struct_fqn) in edges.uses_class {
        accumulator.add_uses_class(fn_fqn, struct_fqn);
    }
    for (derived, base) in edges.class_uses_class {
        accumulator.add_class_uses_class(derived, base);
    }
}

/// Handle Go-specific structure:
/// - Package, struct, and function symbols.
/// - HTTP handler detection (http.HandleFunc, Chi, Gin, Echo patterns).
/// - External API calls.
async fn persist_go_structure(
    graph: &Graph,
    file_path: &str,
    file: &ParsedFile,
    source: &str,
    known_paths: &HashSet<String>,
    project_name: Option<String>,
    accumulator: &mut BatchAccumulator,
    scan_root: &Path,
    go_modules: &[GoModule],
    go_replaces: &[GoReplace],
    persistence: &GraphPersistenceOptions,
    compressor: Option<&CompressorClient>,
) -> Result<(), GraphError> {
    let language = file.language.to_string();
    let package_name = extract_go_package(source);

    emit_limited_parse_warnings(
        "Go",
        file_path,
        extract_go_parse_warnings(&file.tree, source),
        persistence.max_parse_warnings_per_file,
    );

    // Extract structs (as Classes) and functions
    let (structs, functions) = extract_go_symbols(&file.tree, source, package_name.as_deref());
    let class_spans = extract_go_class_spans(&file.tree, source, package_name.as_deref());
    let function_spans = extract_go_function_body_spans(&file.tree, source, package_name.as_deref());

    // Create struct nodes (similar to Class nodes)
    for strct in &structs {
        let class_kind = strct.kind.map(|k| k.to_string());
        let code_bytes = code_bytes_for_span(
            compressor,
            source,
            class_spans.get(&strct.fqn).copied(),
            LanguageId::Go,
        )
        .await;
        let q = query(
            "
            MATCH (f:File { path: $path })
            MERGE (c:Class { fqn: $class_fqn })
            ON CREATE SET c.name = $class_name,
                          c.path = $path,
                          c.project_name = $project_name,
                          c.language = $language,
                          c.kind = $class_kind,
                          c.code_bytes = $code_bytes
            ON MATCH SET  c.name = $class_name,
                          c.path = $path,
                          c.project_name = $project_name,
                          c.language = $language,
                          c.kind = coalesce($class_kind, c.kind),
                          c.code_bytes = coalesce($code_bytes, c.code_bytes)
            MERGE (f)-[:DECLARES_CLASS]->(c)
            ",
        )
        .param("path", file_path.to_string())
        .param("class_fqn", strct.fqn.clone())
        .param("class_name", strct.name.clone())
        .param("project_name", project_name.clone())
        .param("language", language.clone())
        .param("class_kind", class_kind)
        .param(props::CODE_BYTES, code_bytes);

        graph.run(q).await?;
    }

    // Create function nodes
    for func in &functions {
        let code_bytes = code_bytes_for_span(
            compressor,
            source,
            function_spans.get(&func.fqn).copied(),
            LanguageId::Go,
        )
        .await;
        match &func.class_fqn {
            Some(class_fqn) => {
                let q = query(
                    "
                    MATCH (f:File { path: $path })
                    MERGE (cls:Class { fqn: $class_fqn })
                    MERGE (fn:Function { fqn: $fn_fqn })
                    ON CREATE SET fn.name = $fn_name,
                                  fn.path = $path,
                                  fn.project_name = $project_name,
                                  fn.language = $language,
                                  fn.is_pointer_receiver = $is_pointer_receiver,
                                  fn.code_bytes = $code_bytes
                    ON MATCH SET  fn.name = $fn_name,
                                  fn.path = $path,
                                  fn.project_name = $project_name,
                                  fn.language = $language,
                                  fn.is_pointer_receiver = coalesce($is_pointer_receiver, fn.is_pointer_receiver),
                                  fn.code_bytes = coalesce($code_bytes, fn.code_bytes)
                    MERGE (f)-[:DECLARES_FUNCTION]->(fn)
                    MERGE (cls)-[:DECLARES_FUNCTION]->(fn)
                    ",
                )
                .param("path", file_path.to_string())
                .param("class_fqn", class_fqn.clone())
                .param("fn_fqn", func.fqn.clone())
                .param("fn_name", func.name.clone())
                .param("project_name", project_name.clone())
                .param("language", language.clone())
                .param("is_pointer_receiver", func.is_pointer_receiver)
                .param(props::CODE_BYTES, code_bytes.clone());

                graph.run(q).await?;
            }
            None => {
                let q = query(
                    "
                    MATCH (f:File { path: $path })
                    MERGE (fn:Function { fqn: $fn_fqn })
                    ON CREATE SET fn.name = $fn_name,
                                  fn.path = $path,
                                  fn.project_name = $project_name,
                                  fn.language = $language,
                                  fn.is_pointer_receiver = $is_pointer_receiver,
                                  fn.code_bytes = $code_bytes
                    ON MATCH SET  fn.name = $fn_name,
                                  fn.path = $path,
                                  fn.project_name = $project_name,
                                  fn.language = $language,
                                  fn.is_pointer_receiver = coalesce($is_pointer_receiver, fn.is_pointer_receiver),
                                  fn.code_bytes = coalesce($code_bytes, fn.code_bytes)
                    MERGE (f)-[:DECLARES_FUNCTION]->(fn)
                    ",
                )
                .param("path", file_path.to_string())
                .param("fn_fqn", func.fqn.clone())
                .param("fn_name", func.name.clone())
                .param("project_name", project_name.clone())
                .param("language", language.clone())
                .param("is_pointer_receiver", func.is_pointer_receiver)
                .param(props::CODE_BYTES, code_bytes);

                graph.run(q).await?;
            }
        }
    }

    // Go HTTP handler detection
    let endpoints = extract_go_http_endpoints(source);
    for (methods, path_template, handler_name) in endpoints {
        let norm_path = normalize_api_path(&path_template);

        let api_query = query(
            "
            MERGE (api:ApiEndpoint { path: $path })
            ON CREATE SET api.methods      = $methods,
                          api.protocol     = 'http',
                          api.framework    = 'go-http',
                          api.project_name = $project_name,
                          api.norm_path    = $norm_path
            ON MATCH  SET api.methods      = $methods,
                          api.protocol     = coalesce(api.protocol, 'http'),
                          api.framework    = coalesce(api.framework, 'go-http'),
                          api.project_name = coalesce(api.project_name, $project_name),
                          api.norm_path    = coalesce(api.norm_path, $norm_path)
            ",
        )
        .param("path", path_template.clone())
        .param("methods", methods.clone())
        .param("project_name", project_name.clone())
        .param("norm_path", norm_path.clone());

        graph.run(api_query).await?;

        // Link to handler function
        for func in &functions {
            if func.name == handler_name {
                let rel_query = query(
                    "
                    MERGE (fn:Function { fqn: $fn_fqn })
                    MERGE (api:ApiEndpoint { path: $path })
                    MERGE (api)-[:HANDLED_BY]->(fn)
                    ",
                )
                .param("fn_fqn", func.fqn.clone())
                .param("path", path_template.clone());

                graph.run(rel_query).await?;
            }
        }
    }

    // External APIs
    let external_urls = extract_external_http_urls(source);
    for full_url in external_urls {
        let (protocol_opt, host, path) = split_url_protocol_host_and_path(&full_url);
        let protocol = protocol_opt.unwrap_or_else(|| "http".to_string());
        let base_url = format!("{protocol}://{host}");
        let name = host.clone();
        let norm_path = normalize_api_path(&path);

        let ext_query = query(
            "
            MERGE (ext:ExternalApi { base_url: $base_url, norm_path: $norm_path })
            ON CREATE SET ext.name         = $name,
                          ext.path         = $path,
                          ext.protocol     = $protocol,
                          ext.provider     = $provider,
                          ext.project_name = $project_name
            ON MATCH  SET ext.name         = coalesce(ext.name, $name),
                          ext.path         = coalesce(ext.path, $path),
                          ext.protocol     = coalesce(ext.protocol, $protocol),
                          ext.provider     = coalesce(ext.provider, $provider),
                          ext.project_name = coalesce(ext.project_name, $project_name)
            ",
        )
        .param("name", name.clone())
        .param("base_url", base_url.clone())
        .param("path", path.clone())
        .param("norm_path", norm_path.clone())
        .param("protocol", protocol.clone())
        .param("provider", name.clone())
        .param("project_name", project_name.clone());

        graph.run(ext_query).await?;

        // Accumulate CALLS_EXTERNAL_API relationships (global batching)
        for func in &functions {
            accumulator.add_calls_external_api(
                func.fqn.clone(),
                base_url.clone(),
                norm_path.clone(),
            );
        }
    }

    apply_go_call_graph_to_batch(
        accumulator,
        collect_go_call_graph_edges(&file.tree, source, package_name.as_deref()),
    );

    for imp in extract_go_imports(&file.tree, source) {
        if let Some(dep_path) =
            resolve_go_import_to_known_go_file(
                &imp,
                known_paths,
                go_modules,
                go_replaces,
                Some(scan_root),
            )
        {
            let dep_query = query(
                "
                MERGE (src:File { path: $src_path })
                MERGE (dst:File { path: $dst_path })
                MERGE (src)-[:DEPENDS_ON_FILE]->(dst)
                ",
            )
            .param("src_path", file_path.to_string())
            .param("dst_path", dep_path.clone());

            graph.run(dep_query).await?;
        } else if should_log_unresolved_import(
            persistence.verbose_imports,
            is_go_stdlib_import(&imp),
            is_likely_third_party_go_import(&imp),
        ) {
            println!("Go import (unresolved to scanned files): `{}` in {}", imp, file_path);
        }
    }

    Ok(())
}

/// Go parse warnings from Tree-Sitter `ERROR` / missing nodes (CRM-3653).
fn extract_go_parse_warnings(tree: &Tree, source: &str) -> Vec<(usize, usize, String)> {
    let mut out = Vec::new();
    let root = tree.root_node();
    walk_tree(root, |node| {
        if node.kind() == "ERROR" || node.is_missing() {
            let pos = node.start_position();
            let s = node.start_byte() as usize;
            let e = (node.end_byte() as usize).min(source.len());
            let snippet = if s < e {
                source[s..e]
                    .chars()
                    .take(120)
                    .collect::<String>()
                    .replace('\n', " ")
            } else {
                String::new()
            };
            out.push((pos.row + 1, pos.column + 1, snippet));
        }
    });
    out
}

fn go_go_callee_fqn_from_call_expression(
    call: Node,
    source: &str,
    package: Option<&str>,
) -> Option<String> {
    let func_node = call.child_by_field_name("function")?;
    let s = func_node.start_byte() as usize;
    let e = (func_node.end_byte() as usize).min(source.len());
    if s >= e {
        return None;
    }
    let callee_name = source[s..e].trim().to_string();
    if callee_name.is_empty() {
        return None;
    }
    Some(if callee_name.contains('.') {
        callee_name
    } else if let Some(pkg) = package {
        format!("{pkg}.{callee_name}")
    } else {
        callee_name
    })
}

fn go_decl_fqn_from_function_declaration(
    decl: Node,
    source: &str,
    package: Option<&str>,
) -> Option<String> {
    let name_node = decl.child_by_field_name("name")?;
    let s = name_node.start_byte() as usize;
    let e = (name_node.end_byte() as usize).min(source.len());
    if s >= e {
        return None;
    }
    let name = source[s..e].to_string();
    Some(match package {
        Some(pkg) => format!("{pkg}.{name}"),
        None => name,
    })
}

fn go_decl_fqn_from_method_declaration(
    decl: Node,
    source: &str,
    package: Option<&str>,
) -> Option<String> {
    let name_node = decl.child_by_field_name("name")?;
    let s = name_node.start_byte() as usize;
    let e = (name_node.end_byte() as usize).min(source.len());
    if s >= e {
        return None;
    }
    let method_name = source[s..e].to_string();
    let receiver_type = decl.child_by_field_name("receiver").and_then(|r| {
        let mut type_name = None;
        walk_tree(r, |n| {
            if n.kind() == "type_identifier" {
                let s = n.start_byte() as usize;
                let e = (n.end_byte() as usize).min(source.len());
                if e <= source.len() && s < e {
                    type_name = Some(source[s..e].to_string());
                }
            }
        });
        type_name
    })?;
    let class_fqn = match package {
        Some(pkg) => format!("{pkg}.{receiver_type}"),
        None => receiver_type,
    };
    Some(format!("{class_fqn}.{method_name}"))
}

fn go_enclosing_func_decl_fqn_from_inner(node: Node, source: &str, package: Option<&str>) -> Option<String> {
    let mut cur = node.parent();
    while let Some(n) = cur {
        match n.kind() {
            "function_declaration" => return go_decl_fqn_from_function_declaration(n, source, package),
            "method_declaration" => return go_decl_fqn_from_method_declaration(n, source, package),
            _ => cur = n.parent(),
        }
    }
    None
}

/// `go foo()` → caller/callee FQNs (CRM-3652).
fn extract_go_goroutine_calls(
    tree: &Tree,
    source: &str,
    package: Option<&str>,
) -> Vec<(String, String)> {
    let mut out = Vec::new();
    let root = tree.root_node();
    walk_tree(root, |node| {
        if node.kind() != "go_statement" {
            return;
        }
        let Some(caller) = go_enclosing_func_decl_fqn_from_inner(node, source, package) else {
            return;
        };
        let mut i = 0usize;
        while let Some(expr) = node.named_child(i) {
            i += 1;
            if expr.kind() == "call_expression" {
                if let Some(callee) = go_go_callee_fqn_from_call_expression(expr, source, package) {
                    out.push((caller.clone(), callee));
                }
                break;
            }
        }
    });
    out
}

fn go_type_leaf_for_embedding(mut n: Node) -> Node {
    loop {
        if n.kind() == "pointer_type" {
            if let Some(inner) = n.named_child(0) {
                n = inner;
                continue;
            }
        }
        return n;
    }
}

fn go_embedding_type_fqn(type_node: Node, source: &str, package: Option<&str>) -> Option<String> {
    let leaf = go_type_leaf_for_embedding(type_node);
    let s = leaf.start_byte() as usize;
    let e = (leaf.end_byte() as usize).min(source.len());
    if s >= e {
        return None;
    }
    let raw = source[s..e].trim().to_string();
    if raw.is_empty() {
        return None;
    }
    Some(if raw.contains('.') {
        raw
    } else if let Some(pkg) = package {
        format!("{pkg}.{raw}")
    } else {
        raw
    })
}

/// Struct embedding → `(struct_fqn, embedded_type_fqn)` (CRM-3654).
fn extract_go_embedding(
    tree: &Tree,
    source: &str,
    package: Option<&str>,
) -> Vec<(String, String)> {
    let mut out = Vec::new();
    let root = tree.root_node();
    walk_tree(root, |node| {
        if node.kind() != "type_declaration" {
            return;
        }
        let mut i = 0usize;
        while let Some(child) = node.child(i) {
            i += 1;
            if child.kind() != "type_spec" {
                continue;
            }
            let Some(type_n) = child.child_by_field_name("type") else {
                continue;
            };
            if type_n.kind() != "struct_type" {
                continue;
            }
            let Some(name_node) = child.child_by_field_name("name") else {
                continue;
            };
            let s = name_node.start_byte() as usize;
            let e = (name_node.end_byte() as usize).min(source.len());
            if s >= e {
                continue;
            }
            let struct_name = source[s..e].to_string();
            let struct_fqn = match package {
                Some(pkg) => format!("{pkg}.{struct_name}"),
                None => struct_name,
            };
            walk_tree(type_n, |fd| {
                if fd.kind() != "field_declaration" {
                    return;
                }
                if fd.child_by_field_name("name").is_some() {
                    return;
                }
                let Some(ty) = fd.child_by_field_name("type") else {
                    return;
                };
                if let Some(emb) = go_embedding_type_fqn(ty, source, package) {
                    out.push((struct_fqn.clone(), emb));
                }
            });
        }
    });
    out
}

/// Import path strings from `import` declarations (CRM-3656).
fn extract_go_imports(tree: &Tree, source: &str) -> Vec<String> {
    let mut out = Vec::new();
    let root = tree.root_node();
    walk_tree(root, |node| {
        if node.kind() != "import_spec" {
            return;
        }
        let Some(path_node) = node.child_by_field_name("path") else {
            return;
        };
        let s = path_node.start_byte() as usize;
        let e = (path_node.end_byte() as usize).min(source.len());
        if s >= e {
            return;
        }
        let raw = source[s..e].trim();
        let path = raw.trim_matches('`').trim_matches('"').to_string();
        if !path.is_empty() {
            out.push(path);
        }
    });
    out
}

/// Extract Go package name from source
fn extract_go_package(source: &str) -> Option<String> {
    for line in source.lines() {
        let line = line.trim();
        if line.starts_with("package ") {
            let pkg = line["package ".len()..].trim();
            if !pkg.is_empty() {
                return Some(pkg.to_string());
            }
        }
    }
    None
}

/// Extract Go structs, interfaces, and functions from AST (CRM-3654, CRM-3655).
fn extract_go_symbols(
    tree: &Tree,
    source: &str,
    package: Option<&str>,
) -> (Vec<ClassSymbol>, Vec<FunctionSymbol>) {
    let mut structs: Vec<ClassSymbol> = Vec::new();
    let mut functions: Vec<FunctionSymbol> = Vec::new();
    let mut seen_struct_names: HashSet<String> = HashSet::new();

    let root = tree.root_node();
    walk_tree(root, |node| {
        let kind = node.kind();
        match kind {
            "type_declaration" => {
                let mut i = 0usize;
                while let Some(child) = node.child(i) {
                    i += 1;
                    if child.kind() != "type_spec" {
                        continue;
                    }
                    let Some(type_n) = child.child_by_field_name("type") else {
                        continue;
                    };
                    let kind_label: Option<&'static str> = if type_n.kind() == "struct_type" {
                        Some("struct")
                    } else if type_n.kind() == "interface_type" {
                        Some("interface")
                    } else {
                        continue;
                    };
                    let Some(name_node) = child.child_by_field_name("name") else {
                        continue;
                    };
                    let start = name_node.start_byte() as usize;
                    let end = (name_node.end_byte() as usize).min(source.len());
                    if start >= end {
                        continue;
                    }
                    let name = source[start..end].to_string();
                    let fqn = if let Some(pkg) = package {
                        format!("{pkg}.{name}")
                    } else {
                        name.clone()
                    };
                    if seen_struct_names.insert(fqn.clone()) {
                        structs.push(ClassSymbol {
                            name,
                            fqn,
                            kind: kind_label,
                        });
                    }
                }
            }
            "function_declaration" => {
                if let Some(name_node) = node.child_by_field_name("name") {
                    let start = name_node.start_byte() as usize;
                    let end = (name_node.end_byte() as usize).min(source.len());
                    if end <= source.len() && start < end {
                        let name = source[start..end].to_string();
                        let fqn = if let Some(pkg) = package {
                            format!("{pkg}.{name}")
                        } else {
                            name.clone()
                        };
                        functions.push(FunctionSymbol {
                            name,
                            fqn,
                            class_fqn: None,
                            return_type: None,
                            param_types: Vec::new(),
                            param_count: 0,
                            modifiers: Vec::new(),
                            is_pointer_receiver: None,
                        });
                    }
                }
            }
            "method_declaration" => {
                // Methods have a receiver: func (r *Receiver) MethodName() { ... }
                if let Some(name_node) = node.child_by_field_name("name") {
                    let start = name_node.start_byte() as usize;
                    let end = (name_node.end_byte() as usize).min(source.len());
                    if end <= source.len() && start < end {
                        let method_name = source[start..end].to_string();

                        let is_pointer_receiver = node
                            .child_by_field_name("receiver")
                            .map(|r| go_receiver_has_pointer(r))
                            .unwrap_or(false);

                        // Try to get receiver type
                        let receiver_type = node
                            .child_by_field_name("receiver")
                            .and_then(|r| {
                                let mut type_name = None;
                                walk_tree(r, |n| {
                                    if n.kind() == "type_identifier" {
                                        let s = n.start_byte() as usize;
                                        let e = (n.end_byte() as usize).min(source.len());
                                        if e <= source.len() && s < e {
                                            type_name = Some(source[s..e].to_string());
                                        }
                                    }
                                });
                                type_name
                            });

                        let class_fqn = receiver_type.map(|t| {
                            if let Some(pkg) = package {
                                format!("{pkg}.{t}")
                            } else {
                                t
                            }
                        });

                        let fqn = if let Some(ref cls) = class_fqn {
                            format!("{cls}.{method_name}")
                        } else if let Some(pkg) = package {
                            format!("{pkg}.{method_name}")
                        } else {
                            method_name.clone()
                        };

                        functions.push(FunctionSymbol {
                            name: method_name,
                            fqn,
                            class_fqn,
                            return_type: None,
                            param_types: Vec::new(),
                            param_count: 0,
                            modifiers: Vec::new(),
                            is_pointer_receiver: Some(is_pointer_receiver),
                        });
                    }
                }
            }
            _ => {}
        }
    });

    (structs, functions)
}

fn go_receiver_has_pointer(receiver: Node) -> bool {
    let mut ptr = false;
    walk_tree(receiver, |n| {
        if n.kind() == "pointer_type" {
            ptr = true;
        }
    });
    ptr
}

/// Extract Go HTTP handler registrations
fn extract_go_http_endpoints(source: &str) -> Vec<(Vec<String>, String, String)> {
    let mut endpoints: Vec<(Vec<String>, String, String)> = Vec::new();

    for line in source.lines() {
        let trimmed = line.trim();

        // Standard library: http.HandleFunc("/path", handler)
        if trimmed.contains("HandleFunc(") || trimmed.contains("Handle(") {
            if let Some((path, handler)) = extract_go_handler_call(trimmed) {
                endpoints.push((vec!["ANY".to_string()], path, handler));
            }
        }

        // Chi router: r.Get("/path", handler), r.Post("/path", handler)
        for (pattern, method) in [
            (".Get(", "GET"),
            (".Post(", "POST"),
            (".Put(", "PUT"),
            (".Delete(", "DELETE"),
            (".Patch(", "PATCH"),
        ] {
            if trimmed.contains(pattern) {
                if let Some((path, handler)) = extract_go_handler_call(trimmed) {
                    endpoints.push((vec![method.to_string()], path, handler));
                }
            }
        }

        // Gin: router.GET("/path", handler)
        for (pattern, method) in [
            (".GET(", "GET"),
            (".POST(", "POST"),
            (".PUT(", "PUT"),
            (".DELETE(", "DELETE"),
            (".PATCH(", "PATCH"),
        ] {
            if trimmed.contains(pattern) {
                if let Some((path, handler)) = extract_go_handler_call(trimmed) {
                    endpoints.push((vec![method.to_string()], path, handler));
                }
            }
        }

        // Echo: e.GET("/path", handler)
        // Similar pattern to Gin, already covered above
    }

    endpoints
}

/// Extract path and handler from Go HTTP registration calls
fn extract_go_handler_call(line: &str) -> Option<(String, String)> {
    // Find first quoted string (path)
    let first_quote = line.find('"')?;
    let rest = &line[first_quote + 1..];
    let second_quote = rest.find('"')?;
    let path = rest[..second_quote].to_string();

    // Find handler name after the path (last identifier before closing paren)
    let after_path = &rest[second_quote + 1..];
    let comma_idx = after_path.find(',')?;
    let handler_part = &after_path[comma_idx + 1..];

    // Extract handler name (last word before any parenthesis or end)
    let handler = handler_part
        .split(|c: char| c == ')' || c == '(' || c == ',')
        .next()?
        .trim()
        .to_string();

    if handler.is_empty() || path.is_empty() {
        return None;
    }

    Some((path, handler))
}

/// Extract Go struct usage (USES_CLASS relationships)
fn extract_go_used_types(
    tree: &Tree,
    source: &str,
    package: Option<&str>,
) -> Vec<(String, String)> {
    let mut uses: Vec<(String, String)> = Vec::new();
    let root = tree.root_node();

    walk_tree(root, |node| {
        let kind = node.kind();
        if kind != "function_declaration" && kind != "method_declaration" {
            return;
        }

        let func_name = node
            .child_by_field_name("name")
            .and_then(|n| {
                let s = n.start_byte() as usize;
                let e = n.end_byte() as usize;
                if e <= source.len() && s < e {
                    Some(source[s..e].to_string())
                } else {
                    None
                }
            });

        let func_name = match func_name {
            Some(n) => n,
            None => return,
        };

        let func_fqn = if let Some(pkg) = package {
            format!("{pkg}.{func_name}")
        } else {
            func_name
        };

        // Find type identifiers used in the function
        walk_tree(node, |child| {
            if child.kind() == "type_identifier" {
                let s = child.start_byte() as usize;
                let e = child.end_byte() as usize;
                if e <= source.len() && s < e {
                    let type_name = source[s..e].to_string();
                    // Skip built-in types
                    if !is_go_builtin_type(&type_name) {
                        let type_fqn = if let Some(pkg) = package {
                            format!("{pkg}.{type_name}")
                        } else {
                            type_name
                        };
                        uses.push((func_fqn.clone(), type_fqn));
                    }
                }
            }
        });
    });

    uses
}

/// Check if a type is a Go built-in type
fn is_go_builtin_type(name: &str) -> bool {
    matches!(
        name,
        "int" | "int8" | "int16" | "int32" | "int64"
            | "uint" | "uint8" | "uint16" | "uint32" | "uint64" | "uintptr"
            | "float32" | "float64" | "complex64" | "complex128"
            | "bool" | "string" | "byte" | "rune" | "error"
    )
}

/// Extract Go function calls
fn extract_go_calls(
    tree: &Tree,
    source: &str,
    package: Option<&str>,
) -> Vec<(String, String)> {
    let mut calls: Vec<(String, String)> = Vec::new();
    let root = tree.root_node();

    walk_tree(root, |node| {
        let kind = node.kind();
        if kind != "function_declaration" && kind != "method_declaration" {
            return;
        }

        let func_name = node
            .child_by_field_name("name")
            .and_then(|n| {
                let s = n.start_byte() as usize;
                let e = n.end_byte() as usize;
                if e <= source.len() && s < e {
                    Some(source[s..e].to_string())
                } else {
                    None
                }
            });

        let func_name = match func_name {
            Some(n) => n,
            None => return,
        };

        let caller_fqn = if let Some(pkg) = package {
            format!("{pkg}.{func_name}")
        } else {
            func_name
        };

        // Find call expressions
        walk_tree(node, |child| {
            if child.kind() == "call_expression" {
                if let Some(func_node) = child.child_by_field_name("function") {
                    let s = func_node.start_byte() as usize;
                    let e = func_node.end_byte() as usize;
                    if e <= source.len() && s < e {
                        let callee_name = source[s..e].to_string();
                        // Try to build FQN for the callee
                        let callee_fqn = if callee_name.contains('.') {
                            // Already has package/receiver prefix
                            callee_name
                        } else if let Some(pkg) = package {
                            format!("{pkg}.{callee_name}")
                        } else {
                            callee_name
                        };
                        calls.push((caller_fqn.clone(), callee_fqn));
                    }
                }
            }
        });
    });

    calls
}

/// Options for pure IR extraction (no Neo4j).
#[derive(Debug, Clone)]
pub struct ExtractOptions {
    pub verbose_imports: bool,
    pub max_parse_warnings_per_file: usize,
    /// RedCompressor HTTP API for `code_bytes` on symbol nodes in [`ProjectIr`].
    pub compressor: CompressorConfig,
}

impl Default for ExtractOptions {
    fn default() -> Self {
        Self {
            verbose_imports: false,
            max_parse_warnings_per_file: 50,
            compressor: CompressorConfig::default(),
        }
    }
}

/// Body spans keyed by function FQN for a single parsed file.
pub fn function_body_spans_for_file(
    file: &ParsedFile,
    file_path: &str,
    source: &str,
) -> HashMap<String, (usize, usize)> {
    match file.language {
        LanguageId::Java => {
            let package = extract_java_package(source);
            extract_java_method_body_spans(&file.tree, source, package.as_deref())
        }
        LanguageId::CSharp => {
            let namespace = extract_csharp_namespace(&file.tree, source);
            extract_csharp_method_body_spans_map(&file.tree, source, namespace.as_deref())
        }
        LanguageId::Go => {
            let package = extract_go_package(source);
            extract_go_function_body_spans(&file.tree, source, package.as_deref())
        }
        LanguageId::Erlang => {
            let module = resolve_erlang_module_name(&file.path, &file.tree, source);
            module
                .as_ref()
                .map(|m| extract_erlang_function_spans(m, &file.tree, source))
                .unwrap_or_default()
        }
        _ => extract_non_java_function_body_spans(file, source, file_path),
    }
}

/// Class/type declaration spans keyed by FQN (Go struct, C# class, etc.).
pub fn class_body_spans_for_file(
    file: &ParsedFile,
    source: &str,
) -> HashMap<String, (usize, usize)> {
    match file.language {
        LanguageId::Go => {
            let package = extract_go_package(source);
            extract_go_class_spans(&file.tree, source, package.as_deref())
        }
        LanguageId::CSharp => extract_csharp_class_spans(&file.tree, source),
        _ => HashMap::new(),
    }
}

/// Property declaration spans keyed by FQN (C#).
pub fn property_body_spans_for_file(
    file: &ParsedFile,
    source: &str,
) -> HashMap<String, (usize, usize)> {
    match file.language {
        LanguageId::CSharp => extract_csharp_property_spans(&file.tree, source),
        _ => HashMap::new(),
    }
}

/// Fill `code_bytes` on IR symbol nodes via the RedCompressor HTTP API (same as Neo4j persist path).
pub async fn enrich_project_ir_code_bytes(
    ir: &mut ProjectIr,
    root: &Path,
    files: &[ParsedFile],
    config: &CompressorConfig,
) -> Result<(), crate::compress::CompressError> {
    if !config.enabled {
        return Ok(());
    }
    let client = match CompressorClient::from_config(config) {
        Ok(c) => c,
        Err(e) => {
            eprintln!("RedCompressor: failed to create client ({e}); skipping code_bytes");
            return Ok(());
        }
    };
    if let Err(e) = client.health_check().await {
        eprintln!("RedCompressor: health check failed ({e}); compression may be unavailable");
    }

    let mut by_path: HashMap<String, &ParsedFile> = HashMap::new();
    for file in files {
        by_path.insert(neo4j_path_string(root, &file.path), file);
    }

    for func in &mut ir.functions {
        let Some(file) = by_path.get(&func.path) else {
            continue;
        };
        let spans = function_body_spans_for_file(file, &func.path, &file.source);
        let Some(span) = spans.get(&func.fqn).copied() else {
            continue;
        };
        func.code_bytes = code_bytes_for_span(
            Some(&client),
            &file.source,
            Some(span),
            file.language,
        )
        .await;
    }

    for module in &mut ir.modules {
        let Some(file) = by_path.get(&module.path) else {
            continue;
        };
        module.code_bytes =
            compress_full_source(&file.source, LanguageId::Erlang, &client).await;
    }

    for class in &mut ir.classes {
        let Some(file) = by_path.get(&class.path) else {
            continue;
        };
        let spans = class_body_spans_for_file(file, &file.source);
        let Some(span) = spans.get(&class.fqn).copied() else {
            continue;
        };
        class.code_bytes = code_bytes_for_span(
            Some(&client),
            &file.source,
            Some(span),
            file.language,
        )
        .await;
    }

    Ok(())
}

#[derive(Debug, Default)]
struct IrEdgeAccumulator {
    calls_function: HashSet<(String, String)>,
    uses_class: HashSet<(String, String)>,
    class_uses_class: HashSet<(String, String)>,
}

impl IrEdgeAccumulator {
    fn flush_into(&self, edges: &mut Vec<EdgeIr>) {
        for (caller, callee) in &self.calls_function {
            edges.push(EdgeIr {
                kind: EdgeKind::CallsFunction,
                from_label: "Function".into(),
                from_key: caller.clone(),
                to_label: "Function".into(),
                to_key: callee.clone(),
            });
        }
        for (fn_fqn, cls_fqn) in &self.uses_class {
            edges.push(EdgeIr {
                kind: EdgeKind::UsesClass,
                from_label: "Function".into(),
                from_key: fn_fqn.clone(),
                to_label: "Class".into(),
                to_key: cls_fqn.clone(),
            });
        }
        for (derived, base) in &self.class_uses_class {
            edges.push(EdgeIr {
                kind: EdgeKind::ClassUsesClass,
                from_label: "Class".into(),
                from_key: derived.clone(),
                to_label: "Class".into(),
                to_key: base.clone(),
            });
        }
    }
}

fn push_depends_on_file(edges: &mut Vec<EdgeIr>, src: &str, dst: &str) {
    edges.push(EdgeIr {
        kind: EdgeKind::DependsOnFile,
        from_label: "File".into(),
        from_key: src.to_string(),
        to_label: "File".into(),
        to_key: dst.to_string(),
    });
}

fn push_declares_function(edges: &mut Vec<EdgeIr>, from_label: &str, from_key: &str, fqn: &str) {
    edges.push(EdgeIr {
        kind: EdgeKind::DeclaresFunction,
        from_label: from_label.into(),
        from_key: from_key.to_string(),
        to_label: "Function".into(),
        to_key: fqn.to_string(),
    });
}

/// Build a language-agnostic [`ProjectIr`] from parsed files (no Neo4j I/O).
pub fn build_project_ir(
    root: &Path,
    files: &[ParsedFile],
    _options: &ExtractOptions,
) -> ProjectIr {
    use crate::ir::{ApiEndpointIr, FileIr};

    let mut ir = ProjectIr::empty();
    let mut accumulator = IrEdgeAccumulator::default();

    let known_paths: HashSet<String> = files
        .iter()
        .map(|f| neo4j_path_string(root, &f.path))
        .collect();

    let go_modules = discover_go_modules(root, false).unwrap_or_default();
    let go_replaces = discover_go_replaces(root, false).unwrap_or_default();
    let csharp_batch_index = build_csharp_batch_index(files, root);
    let erlang_module_index = build_erlang_module_index(files);

    for file in files {
        let path = neo4j_path_string(root, &file.path);
        let language = file.language.to_string();
        let project_name = derive_project_name(&file.path, root);
        let source = &file.source;

        ir.files.push(FileIr {
            path: path.clone(),
            language: language.clone(),
            framework: None,
            project_name: project_name.clone(),
        });

        match file.language {
            LanguageId::Java => {
                append_java_class_ir(&mut ir, &path, project_name.clone(), &file.tree, source);
                let package = extract_java_package(source);
                let (_, methods) =
                    extract_java_symbols(&file.tree, source, package.as_deref());
                for func in &methods {
                    ir.functions.push(FunctionIr {
                        name: func.name.clone(),
                        fqn: func.fqn.clone(),
                        path: path.clone(),
                        language: language.clone(),
                        framework: None,
                        project_name: project_name.clone(),
                        arity: None,
                        return_type: func.return_type.clone(),
                        param_count: Some(func.param_count as u32),
                        param_types: func.param_types.clone(),
                        code_bytes: None,
                    });
                    if let Some(class_fqn) = &func.class_fqn {
                        push_declares_function(&mut ir.edges, "Class", class_fqn, &func.fqn);
                    }
                    push_declares_function(&mut ir.edges, "File", &path, &func.fqn);
                }
                for (derived, base) in
                    extract_java_inheritance_edges(&file.tree, source, package.as_deref())
                {
                    accumulator.class_uses_class.insert((derived, base));
                }
                for (cls, dep) in
                    extract_java_injected_dependencies(&file.tree, source, package.as_deref())
                {
                    accumulator.class_uses_class.insert((cls, dep));
                }
                for (caller, callee) in extract_java_calls(&file.tree, source, package.as_deref()) {
                    accumulator.calls_function.insert((caller, callee));
                }
                for import_fqn in extract_internal_java_imports(source) {
                    if let Some(dep_path) = map_import_to_project_path(&path, &import_fqn) {
                        if known_paths.contains(&dep_path) {
                            push_depends_on_file(&mut ir.edges, &path, &dep_path);
                        }
                    }
                }
                for (http_methods, path_template, handler_name) in extract_java_spring_endpoints(source)
                {
                    let norm_path = normalize_api_path(&path_template);
                    ir.api_endpoints.push(ApiEndpointIr {
                        methods: http_methods.clone(),
                        path: path_template.clone(),
                        protocol: Some("http".into()),
                        framework: Some("spring".into()),
                        project_name: project_name.clone(),
                    });
                    if let Some(handler_fqn) =
                        resolve_java_handler_fqn(&http_methods, &handler_name, &ir)
                    {
                        ir.edges.push(EdgeIr {
                            kind: EdgeKind::HandlesApi,
                            from_label: "ApiEndpoint".into(),
                            from_key: api_endpoint_key(&http_methods, &path_template),
                            to_label: "Function".into(),
                            to_key: handler_fqn,
                        });
                    }
                    let _ = norm_path;
                }
            }
            LanguageId::CSharp => {
                append_csharp_structural_ir(
                    &mut ir,
                    &path,
                    project_name.clone(),
                    &file.tree,
                    source,
                );
                let namespace = extract_csharp_namespace(&file.tree, source);
                let using_summary = extract_csharp_using_summary(&file.tree, source);
                let (classes, methods, _) = extract_csharp_symbols(&file.tree, source);
                for func in &methods {
                    ir.functions.push(FunctionIr {
                        name: func.name.clone(),
                        fqn: func.fqn.clone(),
                        path: path.clone(),
                        language: language.clone(),
                        framework: None,
                        project_name: project_name.clone(),
                        arity: None,
                        return_type: func.return_type.clone(),
                        param_count: Some(func.param_count as u32),
                        param_types: func.param_types.clone(),
                        code_bytes: None,
                    });
                    if let Some(class_fqn) = &func.class_fqn {
                        push_declares_function(&mut ir.edges, "Class", class_fqn, &func.fqn);
                    }
                    push_declares_function(&mut ir.edges, "File", &path, &func.fqn);
                }
                for ns in &using_summary.namespace_imports {
                    let Some(dep_paths) = csharp_batch_index.namespace_to_paths.get(ns) else {
                        continue;
                    };
                    for dep_path in dep_paths {
                        if dep_path == &path || !known_paths.contains(dep_path) {
                            continue;
                        }
                        push_depends_on_file(&mut ir.edges, &path, dep_path);
                    }
                }
                for (derived, base) in extract_csharp_class_inheritance_edges(
                    &file.tree,
                    source,
                    namespace.as_deref(),
                    &using_summary,
                    &csharp_batch_index,
                ) {
                    accumulator.class_uses_class.insert((derived, base));
                }
                for (fn_fqn, class_fqn) in extract_csharp_used_classes(
                    &file.tree,
                    source,
                    namespace.as_deref(),
                    &using_summary,
                    &csharp_batch_index,
                ) {
                    accumulator.uses_class.insert((fn_fqn, class_fqn));
                }
                for (caller, callee) in extract_csharp_calls(
                    &file.tree,
                    source,
                    namespace.as_deref(),
                    &using_summary,
                    &csharp_batch_index,
                ) {
                    accumulator.calls_function.insert((caller, callee));
                }
                let _ = classes;
            }
            LanguageId::Erlang => {
                extract_erlang_to_ir(
                    &mut ir,
                    &mut accumulator,
                    file,
                    &path,
                    source,
                    project_name.clone(),
                    &language,
                    &erlang_module_index,
                );
            }
            LanguageId::Go => {
                let package_name = extract_go_package(source);
                let (structs, functions) =
                    extract_go_symbols(&file.tree, source, package_name.as_deref());
                for s in &structs {
                    ir.classes.push(ClassIr {
                        fqn: s.fqn.clone(),
                        name: s.name.clone(),
                        path: path.clone(),
                        language: language.clone(),
                        project_name: project_name.clone(),
                        kind: s.kind.map(str::to_string),
                        code_bytes: None,
                    });
                    ir.edges.push(EdgeIr {
                        kind: EdgeKind::DeclaresClass,
                        from_label: "File".into(),
                        from_key: path.clone(),
                        to_label: "Class".into(),
                        to_key: s.fqn.clone(),
                    });
                }
                for func in &functions {
                    ir.functions.push(FunctionIr {
                        name: func.name.clone(),
                        fqn: func.fqn.clone(),
                        path: path.clone(),
                        language: language.clone(),
                        framework: None,
                        project_name: project_name.clone(),
                        arity: None,
                        return_type: func.return_type.clone(),
                        param_count: Some(func.param_count as u32),
                        param_types: func.param_types.clone(),
                        code_bytes: None,
                    });
                    if let Some(class_fqn) = &func.class_fqn {
                        push_declares_function(&mut ir.edges, "Class", class_fqn, &func.fqn);
                    }
                    push_declares_function(&mut ir.edges, "File", &path, &func.fqn);
                }
                for import_path in extract_go_imports(&file.tree, source) {
                    if let Some(dep) = resolve_go_import_to_known_go_file(
                        &import_path,
                        &known_paths,
                        &go_modules,
                        &go_replaces,
                        Some(root),
                    ) {
                        push_depends_on_file(&mut ir.edges, &path, &dep);
                    }
                }
                apply_go_call_graph_to_ir(
                    &mut accumulator,
                    collect_go_call_graph_edges(&file.tree, source, package_name.as_deref()),
                );
            }
            _ => {
                extract_non_java_to_ir(
                    &mut ir,
                    &mut accumulator,
                    file,
                    &path,
                    source,
                    project_name.clone(),
                    &language,
                    &known_paths,
                    _options,
                );
            }
        }
    }

    accumulator.flush_into(&mut ir.edges);
    apply_same_api_edges(&mut ir);
    ir
}

fn resolve_java_handler_fqn(
    _methods: &[String],
    handler_name: &str,
    ir: &ProjectIr,
) -> Option<String> {
    ir.functions
        .iter()
        .find(|f| f.name == handler_name)
        .map(|f| f.fqn.clone())
}

fn extract_erlang_to_ir(
    ir: &mut ProjectIr,
    accumulator: &mut IrEdgeAccumulator,
    file: &ParsedFile,
    file_path: &str,
    source: &str,
    project_name: Option<String>,
    language: &str,
    erlang_module_index: &HashMap<String, ErlangModuleSnapshot>,
) {
    use crate::ir::{ApiEndpointIr, BehaviourIr, CallbackIr, ExternalApiIr, ModuleIr};

    let module_name = resolve_erlang_module_name(&file.path, &file.tree, source);
    let erlang_meta = extract_erlang_behaviour_metadata_from_tree(&file.tree, source);

    if let Some(module_name) = module_name.as_ref() {
        ir.modules.push(ModuleIr {
            name: module_name.clone(),
            path: file_path.to_string(),
            language: language.to_string(),
            framework: None,
            project_name: project_name.clone(),
            code_bytes: None,
        });
        ir.edges.push(EdgeIr {
            kind: EdgeKind::DeclaresModule,
            from_label: "File".into(),
            from_key: file_path.to_string(),
            to_label: "Module".into(),
            to_key: module_key(module_name, file_path),
        });
    }

    let functions = if let Some(module_name) = module_name.as_ref() {
        extract_erlang_functions(module_name, &file.tree, source)
    } else {
        Vec::new()
    };

    for (fun_name, arity, fqn) in &functions {
        ir.functions.push(FunctionIr {
            name: fun_name.clone(),
            fqn: fqn.clone(),
            path: file_path.to_string(),
            language: language.to_string(),
            framework: None,
            project_name: project_name.clone(),
            arity: Some(*arity),
            return_type: None,
            param_count: None,
            param_types: vec![],
            code_bytes: None,
        });
        push_declares_function(&mut ir.edges, "File", file_path, fqn);
        if let Some(module_name) = module_name.as_ref() {
            push_declares_function(&mut ir.edges, "Module", &module_key(module_name, file_path), fqn);
        }
    }

    let callback_contracts = collect_callback_contracts_for_module(
        module_name.as_deref(),
        &erlang_meta.behaviour_usages,
        &erlang_meta.declared_callbacks,
        &erlang_meta.optional_callbacks,
    );

    if let Some(module_name) = module_name.as_ref() {
        for behaviour in &erlang_meta.behaviour_usages {
            ir.behaviours.push(BehaviourIr {
                name: behaviour.clone(),
                path: None,
                language: Some(language.to_string()),
                project_name: project_name.clone(),
            });
            ir.edges.push(EdgeIr {
                kind: EdgeKind::ImplementsBehaviour,
                from_label: "Module".into(),
                from_key: module_key(module_name, file_path),
                to_label: "Behaviour".into(),
                to_key: behaviour.clone(),
            });
            let dep_path = guess_erlang_file_path_from_module(file_path, behaviour);
            push_depends_on_file(&mut ir.edges, file_path, &dep_path);
        }

        if !erlang_meta.declared_callbacks.is_empty() {
            ir.behaviours.push(BehaviourIr {
                name: module_name.clone(),
                path: Some(file_path.to_string()),
                language: Some(language.to_string()),
                project_name: project_name.clone(),
            });
            ir.edges.push(EdgeIr {
                kind: EdgeKind::DeclaresBehaviour,
                from_label: "File".into(),
                from_key: file_path.to_string(),
                to_label: "Behaviour".into(),
                to_key: module_name.clone(),
            });
        }

        for parent in &erlang_meta.behaviour_extensions {
            ir.edges.push(EdgeIr {
                kind: EdgeKind::ExtendsBehaviour,
                from_label: "Behaviour".into(),
                from_key: module_name.clone(),
                to_label: "Behaviour".into(),
                to_key: parent.clone(),
            });
        }
    }

    for contract in &callback_contracts {
        let callback_fqn = format!(
            "{}:{}/{}",
            contract.behaviour, contract.name, contract.arity
        );
        ir.callbacks.push(CallbackIr {
            name: contract.name.clone(),
            fqn: callback_fqn.clone(),
            arity: contract.arity,
            optional: contract.optional,
            language: Some(language.to_string()),
            project_name: project_name.clone(),
        });
        ir.edges.push(EdgeIr {
            kind: EdgeKind::DeclaresCallback,
            from_label: "Behaviour".into(),
            from_key: contract.behaviour.clone(),
            to_label: "Callback".into(),
            to_key: callback_fqn.clone(),
        });
    }

    let function_by_sig: HashMap<(String, u32), String> = functions
        .iter()
        .map(|(name, arity, fqn)| ((name.clone(), *arity), fqn.clone()))
        .collect();

    for contract in &callback_contracts {
        let key = (contract.name.clone(), contract.arity);
        let Some(fn_fqn) = function_by_sig.get(&key) else {
            continue;
        };
        let callback_fqn = format!(
            "{}:{}/{}",
            contract.behaviour, contract.name, contract.arity
        );
        ir.edges.push(EdgeIr {
            kind: EdgeKind::ImplementsCallback,
            from_label: "Function".into(),
            from_key: fn_fqn.clone(),
            to_label: "Callback".into(),
            to_key: callback_fqn.clone(),
        });
    }

    for (name, arity) in &erlang_meta.overridden_callbacks {
        let key = (name.clone(), *arity);
        let Some(fn_fqn) = function_by_sig.get(&key) else {
            continue;
        };
        for contract in callback_contracts
            .iter()
            .filter(|c| c.name == *name && c.arity == *arity)
        {
            let callback_fqn = format!(
                "{}:{}/{}",
                contract.behaviour, contract.name, contract.arity
            );
            ir.edges.push(EdgeIr {
                kind: EdgeKind::OverridesCallback,
                from_label: "Function".into(),
                from_key: fn_fqn.clone(),
                to_label: "Callback".into(),
                to_key: callback_fqn,
            });
        }
    }

    for (methods, path_template, handler_module) in extract_erlang_api_endpoints(&file.tree, source)
    {
        let methods_owned: Vec<String> = methods.iter().map(|s| s.to_string()).collect();
        ir.api_endpoints.push(ApiEndpointIr {
            methods: methods_owned.clone(),
            path: path_template.clone(),
            protocol: Some("http".into()),
            framework: Some("cowboy".into()),
            project_name: project_name.clone(),
        });
        for fqn in select_endpoint_handler_fqns(&handler_module, erlang_module_index) {
            ir.edges.push(EdgeIr {
                kind: EdgeKind::HandlesApi,
                from_label: "ApiEndpoint".into(),
                from_key: api_endpoint_key(&methods_owned, &path_template),
                to_label: "Function".into(),
                to_key: fqn,
            });
        }
    }

    for full_url in extract_external_http_urls_from_tree(&file.tree, source) {
        let (protocol_opt, host, url_path) = split_url_protocol_host_and_path(&full_url);
        let protocol = protocol_opt.unwrap_or_else(|| "http".to_string());
        let base_url = format!("{protocol}://{host}");
        let norm_path = normalize_api_path(&url_path);
        ir.external_apis.push(ExternalApiIr {
            name: host.clone(),
            base_url: Some(base_url.clone()),
            protocol: Some(protocol),
            provider: Some(host),
            service: None,
            norm_path: Some(norm_path.clone()),
        });
        for (_, _, fqn) in &functions {
            ir.edges.push(EdgeIr {
                kind: EdgeKind::CallsExternalApi,
                from_label: "Function".into(),
                from_key: fqn.clone(),
                to_label: "ExternalApi".into(),
                to_key: external_api_key(&base_url, &norm_path),
            });
        }
    }

    if let Some(module_name) = module_name.as_ref() {
        let function_by_sig: HashMap<(String, u32), String> = functions
            .iter()
            .map(|(name, arity, fqn)| ((name.clone(), *arity), fqn.clone()))
            .collect();
        for (caller, callee) in extract_erlang_call_edges(
            &file.tree,
            source,
            Some(module_name.as_str()),
            &function_by_sig,
        ) {
            accumulator.calls_function.insert((caller, callee));
        }
    }
}

fn extract_non_java_to_ir(
    ir: &mut ProjectIr,
    accumulator: &mut IrEdgeAccumulator,
    file: &ParsedFile,
    file_path: &str,
    source: &str,
    project_name: Option<String>,
    language: &str,
    known_paths: &HashSet<String>,
    options: &ExtractOptions,
) {
    let functions = extract_non_java_function_symbols(file, source, file_path);
    let mut name_to_fqn_depth: HashMap<String, (String, usize)> = HashMap::new();
    for f in &functions {
        let logical = f
            .fqn
            .split_once("::")
            .map(|(_, l)| l)
            .unwrap_or(f.fqn.as_str());
        let (short, depth) = non_java_short_name_and_depth(file.language, logical);
        name_to_fqn_depth
            .entry(short)
            .and_modify(|(existing_fqn, existing_depth)| {
                if depth > *existing_depth {
                    *existing_fqn = f.fqn.clone();
                    *existing_depth = depth;
                }
            })
            .or_insert_with(|| (f.fqn.clone(), depth));
    }
    let name_to_fqn: HashMap<String, String> = name_to_fqn_depth
        .into_iter()
        .map(|(k, (v, _))| (k, v))
        .collect();

    for func in &functions {
        ir.functions.push(FunctionIr {
            name: func.name.clone(),
            fqn: func.fqn.clone(),
            path: file_path.to_string(),
            language: language.to_string(),
            framework: None,
            project_name: project_name.clone(),
            arity: None,
            return_type: func.return_type.clone(),
            param_count: Some(func.param_count as u32),
            param_types: func.param_types.clone(),
            code_bytes: None,
        });
        push_declares_function(&mut ir.edges, "File", file_path, &func.fqn);
    }

    match file.language {
        LanguageId::Python => {
            for imp in extract_python_import_modules(&file.tree, source) {
                if let Some(dep) = resolve_python_import_to_known_file(&imp, known_paths) {
                    push_depends_on_file(&mut ir.edges, file_path, &dep);
                } else if should_log_unresolved_import(
                    options.verbose_imports,
                    is_python_stdlib_top_level(&imp),
                    is_python_common_external_top_level(&imp),
                ) {
                    eprintln!(
                        "Python import (unresolved to scanned files): `{imp}` in {file_path}"
                    );
                }
            }
            for (caller, callee) in
                extract_python_intrafile_calls(&file.tree, source, file_path, &name_to_fqn)
            {
                accumulator.calls_function.insert((caller, callee));
            }
        }
        LanguageId::JavaScript | LanguageId::TypeScript | LanguageId::Tsx => {
            for spec in extract_js_ts_import_specifiers(&file.tree, source) {
                if let Some(dep) =
                    resolve_js_ts_import_to_known_file(&spec, file_path, known_paths)
                {
                    push_depends_on_file(&mut ir.edges, file_path, &dep);
                } else if options.verbose_imports {
                    eprintln!("JS/TS import (unresolved): `{spec}` in {file_path}");
                }
            }
            for (caller, callee) in extract_js_ts_intrafile_calls(
                &file.tree,
                source,
                file_path,
                file.language,
                &name_to_fqn,
            ) {
                accumulator.calls_function.insert((caller, callee));
            }
        }
        LanguageId::Rust => {
            for use_path in extract_rust_use_paths(&file.tree, source) {
                if let Some(dep) =
                    resolve_rust_use_to_known_file(&use_path, file_path, known_paths)
                {
                    push_depends_on_file(&mut ir.edges, file_path, &dep);
                } else if options.verbose_imports {
                    eprintln!(
                        "Rust use (unresolved to scanned files): `{}` in {file_path}",
                        use_path.join("::")
                    );
                }
            }
            for (caller, callee) in
                extract_rust_intrafile_calls(&file.tree, source, file_path, &name_to_fqn)
            {
                accumulator.calls_function.insert((caller, callee));
            }
        }
        _ => {}
    }
}

fn apply_same_api_edges(ir: &mut ProjectIr) {
    use crate::ir::{api_endpoint_key, external_api_key};
    for ep in &ir.api_endpoints {
        let ep_norm = normalize_api_path(&ep.path);
        for ext in &ir.external_apis {
            if ext.norm_path.as_deref() == Some(ep_norm.as_str()) {
                ir.edges.push(EdgeIr {
                    kind: EdgeKind::SameApi,
                    from_label: "ApiEndpoint".into(),
                    from_key: api_endpoint_key(&ep.methods, &ep.path),
                    to_label: "ExternalApi".into(),
                    to_key: if let (Some(b), Some(n)) = (&ext.base_url, &ext.norm_path) {
                        external_api_key(b, n)
                    } else {
                        ext.name.clone()
                    },
                });
            }
        }
    }
}

/// Persist a pre-built [`ProjectIr`] into Neo4j (server/webhook adapter path).
///
/// Prefer building IR via [`build_project_ir`] so client and server share the same
/// extraction logic; this function maps IR nodes/edges to MERGE queries.
pub async fn persist_project_ir_to_neo4j(
    cfg: &Neo4jConfig,
    ir: &ProjectIr,
    clean: bool,
) -> Result<(), GraphError> {
    let graph = Graph::new(&cfg.uri, &cfg.user, &cfg.password).await?;

    if clean {
        graph.run(query("MATCH (n) DETACH DELETE n")).await?;
    }

    for f in &ir.files {
        let q = query(
            "
            MERGE (n:File { path: $path })
            SET n.language = $language, n.project_name = $project_name
            ",
        )
        .param("path", f.path.clone())
        .param("language", f.language.clone())
        .param("project_name", f.project_name.clone());
        graph.run(q).await?;
    }

    for m in &ir.modules {
        let q = query(
            "
            MERGE (n:Module { name: $name, path: $path })
            ON CREATE SET n.language = $language, n.project_name = $project_name,
                          n.code_bytes = $code_bytes
            ON MATCH SET  n.language = $language, n.project_name = $project_name,
                          n.code_bytes = coalesce($code_bytes, n.code_bytes)
            ",
        )
        .param("name", m.name.clone())
        .param("path", m.path.clone())
        .param("language", m.language.clone())
        .param("project_name", m.project_name.clone())
        .param(props::CODE_BYTES, m.code_bytes.clone());
        graph.run(q).await?;
    }

    for c in &ir.classes {
        let q = query(
            "
            MERGE (n:Class { fqn: $fqn })
            ON CREATE SET n.name = $name, n.path = $path, n.language = $language,
                          n.project_name = $project_name, n.kind = $kind,
                          n.code_bytes = $code_bytes
            ON MATCH SET  n.name = $name, n.path = $path, n.language = $language,
                          n.project_name = $project_name, n.kind = coalesce($kind, n.kind),
                          n.code_bytes = coalesce($code_bytes, n.code_bytes)
            ",
        )
        .param("fqn", c.fqn.clone())
        .param("name", c.name.clone())
        .param("path", c.path.clone())
        .param("language", c.language.clone())
        .param("project_name", c.project_name.clone())
        .param("kind", c.kind.clone())
        .param(props::CODE_BYTES, c.code_bytes.clone());
        graph.run(q).await?;
    }

    for f in &ir.functions {
        let q = query(
            "
            MERGE (n:Function { fqn: $fqn })
            ON CREATE SET n.name = $name, n.path = $path, n.language = $language,
                          n.project_name = $project_name, n.arity = $arity,
                          n.return_type = $return_type, n.param_count = $param_count,
                          n.code_bytes = $code_bytes
            ON MATCH SET  n.name = $name, n.path = $path, n.language = $language,
                          n.project_name = $project_name, n.arity = $arity,
                          n.return_type = $return_type, n.param_count = $param_count,
                          n.code_bytes = coalesce($code_bytes, n.code_bytes)
            ",
        )
        .param("fqn", f.fqn.clone())
        .param("name", f.name.clone())
        .param("path", f.path.clone())
        .param("language", f.language.clone())
        .param("project_name", f.project_name.clone())
        .param("arity", f.arity.map(|a| a as i64))
        .param("return_type", f.return_type.clone())
        .param("param_count", f.param_count.map(|c| c as i64))
        .param(props::CODE_BYTES, f.code_bytes.clone());
        graph.run(q).await?;
    }

    for edge in &ir.edges {
        let rel = edge.kind.to_rel_type().to_string();
        let q = match edge.from_label.as_str() {
            "Module" if edge.to_label == "Function" || edge.to_label == "Module" => {
                let (name, path) = parse_module_key(&edge.from_key).unwrap_or_default();
                let cypher = format!(
                    "
                    MERGE (a:Module {{ name: $from_name, path: $from_path }})
                    MERGE (b:{lbl_b} {{ {key_b}: $to_key }})
                    MERGE (a)-[:{rel}]->(b)
                    ",
                    lbl_b = edge.to_label,
                    key_b = stable_key_property(&edge.to_label),
                    rel = rel,
                );
                query(&cypher)
                    .param("from_name", name)
                    .param("from_path", path)
                    .param("to_key", edge.to_key.clone())
            }
            _ => {
                let cypher = format!(
                    "
                    MERGE (a:{lbl_a} {{ {key_a}: $from_key }})
                    MERGE (b:{lbl_b} {{ {key_b}: $to_key }})
                    MERGE (a)-[:{rel}]->(b)
                    ",
                    lbl_a = edge.from_label,
                    key_a = stable_key_property(&edge.from_label),
                    lbl_b = edge.to_label,
                    key_b = stable_key_property(&edge.to_label),
                    rel = rel,
                );
                query(&cypher)
                    .param("from_key", edge.from_key.clone())
                    .param("to_key", edge.to_key.clone())
            }
        };
        graph.run(q).await?;
    }

    Ok(())
}

fn parse_module_key(key: &str) -> Option<(String, String)> {
    key.split_once('@').map(|(n, p)| (n.to_string(), p.to_string()))
}

fn stable_key_property(label: &str) -> &'static str {
    match label {
        "File" => "path",
        "Module" => "name",
        "Function" | "Class" | "Property" | "Callback" => "fqn",
        "Behaviour" => "name",
        "ApiEndpoint" => "path",
        "ExternalApi" => "name",
        _ => "name",
    }
}

//child submodule for test submodule
#[cfg(test)]  //only can be used for test builds  
mod tests {
    use super::*;
    use crate::ir::{EdgeKind, ProjectIr};
    use crate::scanner::ParsedFile;
    use crate::{parse_once, LanguageId};
    use std::collections::HashSet;
    use std::path::{Path, PathBuf};
    //Resolve module name from Erlang -module(...) attribute

    #[test]
    fn append_csharp_structural_ir_populates_classes_properties_and_edges() {
        let src = r#"
namespace Ns {
  public class C {
    public string Name { get; set; }
  }
}
"#;
        let tree = parse_once(LanguageId::CSharp, src).expect("parse C#");
        let mut ir = ProjectIr::empty();
        append_csharp_structural_ir(&mut ir, "/src/C.cs", None, &tree, src);
        assert!(ir.classes.iter().any(|c| c.fqn == "Ns.C"));
        assert!(ir.properties.iter().any(|p| p.fqn == "Ns.C.Name"));
        assert!(
            ir.edges
                .iter()
                .any(|e| e.kind == EdgeKind::DeclaresClass && e.to_key == "Ns.C")
        );
        assert!(ir
            .edges
            .iter()
            .any(|e| e.kind == EdgeKind::DeclaresProperty && e.to_key == "Ns.C.Name"));
    }

    #[test]
    fn csharp_using_summary_parses_ast_and_filters_system_microsoft() {
        let src = r#"
using System;
using System.Collections.Generic;
using Microsoft.Extensions.Logging;
using OtherNs;
using static System.Math;
using AliasType = OtherNs.SomeType;

namespace ConsumerNs { class C { void M() { } } }
"#;
        let tree = parse_once(LanguageId::CSharp, src).expect("parse C#");
        let sum = extract_csharp_using_summary(&tree, src);
        assert!(sum.namespace_imports.contains(&"OtherNs".to_string()));
        assert!(!sum
            .namespace_imports
            .iter()
            .any(|n| n.starts_with("System") || n.starts_with("Microsoft")));
        assert_eq!(
            sum.alias_map.get("AliasType").map(String::as_str),
            Some("OtherNs.SomeType")
        );
    }

    #[test]
    fn csharp_global_using_included_in_summary() {
        let src = r#"
global using SharedNs;

namespace N { class C { } }
"#;
        let tree = parse_once(LanguageId::CSharp, src).expect("parse C#");
        let sum = extract_csharp_using_summary(&tree, src);
        assert!(sum.namespace_imports.contains(&"SharedNs".to_string()));
    }

    #[test]
    fn csharp_api_endpoints_multiline_http_get_attribute() {
        let src = r#"
namespace N {
  public class C {
    [HttpGet(
      "/x")]
    public void GetIt() { }
  }
}
"#;
        let tree = parse_once(LanguageId::CSharp, src).expect("parse C#");
        let eps = extract_csharp_api_endpoints_from_tree(&tree, src);
        assert_eq!(eps.len(), 1);
        assert_eq!(eps[0].0, vec!["GET"]);
        assert_eq!(eps[0].1, "/x");
        assert_eq!(eps[0].2, "GetIt");
    }

    #[test]
    fn csharp_api_endpoints_class_route_plus_method_http_get() {
        let src = r#"
namespace N {
  [Route("api/v1")]
  public class OrdersController {
    [HttpGet("orders")]
    public void Get() { }
  }
}
"#;
        let tree = parse_once(LanguageId::CSharp, src).expect("parse C#");
        let eps = extract_csharp_api_endpoints_from_tree(&tree, src);
        assert_eq!(eps.len(), 1);
        assert_eq!(eps[0].0, vec!["GET"]);
        assert_eq!(eps[0].1, "/api/v1/orders");
        assert_eq!(eps[0].2, "Get");
    }

    #[test]
    fn csharp_api_endpoints_single_line_http_get_regression() {
        let src = r#"
namespace N {
  public class C {
    [HttpGet("/api/orders")]
    public void List() { }
  }
}
"#;
        let tree = parse_once(LanguageId::CSharp, src).expect("parse C#");
        let eps = extract_csharp_api_endpoints_from_tree(&tree, src);
        assert_eq!(eps.len(), 1);
        assert_eq!(eps[0].1, "/api/orders");
        assert_eq!(eps[0].2, "List");
    }

    #[test]
    fn csharp_api_endpoints_comment_with_fake_attribute_not_parsed() {
        let src = r#"
namespace N {
  public class C {
    // [HttpGet("/fake")]
    [HttpGet("/real")]
    public void A() { }
  }
}
"#;
        let tree = parse_once(LanguageId::CSharp, src).expect("parse C#");
        let eps = extract_csharp_api_endpoints_from_tree(&tree, src);
        assert_eq!(eps.len(), 1);
        assert_eq!(eps[0].1, "/real");
    }

    #[test]
    fn csharp_api_endpoints_comment_only_does_not_create_endpoint() {
        let src = r#"
namespace N {
  public class C {
    // [HttpGet("/fake")]
    public void M() { }
  }
}
"#;
        let tree = parse_once(LanguageId::CSharp, src).expect("parse C#");
        let eps = extract_csharp_api_endpoints_from_tree(&tree, src);
        assert!(eps.is_empty(), "expected no endpoints, got {eps:?}");
    }

    #[test]
    fn csharp_symbols_nested_class_fqns() {
        let src = r#"
namespace N {
  public class Outer {
    public class Inner {
      public void M() { }
    }
  }
}
"#;
        let tree = parse_once(LanguageId::CSharp, src).expect("parse C#");
        let (classes, methods, _) = extract_csharp_symbols(&tree, src);
        let fqns: Vec<&str> = classes.iter().map(|c| c.fqn.as_str()).collect();
        assert!(fqns.contains(&"N.Outer"));
        assert!(fqns.contains(&"N.Outer.Inner"));
        let m = methods.iter().find(|f| f.name == "M").expect("method M");
        assert_eq!(m.class_fqn.as_deref(), Some("N.Outer.Inner"));
        assert_eq!(m.fqn, "N.Outer.Inner.M");
    }

    #[test]
    fn csharp_symbols_enum_kind_and_fqn() {
        let src = r#"
namespace N {
  public enum Color { Red, Green }
}
"#;
        let tree = parse_once(LanguageId::CSharp, src).expect("parse C#");
        let (classes, _, _) = extract_csharp_symbols(&tree, src);
        let e = classes.iter().find(|c| c.name == "Color").expect("enum Color");
        assert_eq!(e.fqn, "N.Color");
        assert_eq!(e.kind, Some("enum"));
    }

    #[test]
    fn csharp_symbols_record_kind_and_fqn() {
        let src = r#"
namespace N {
  public record Person(string Name);
}
"#;
        let tree = parse_once(LanguageId::CSharp, src).expect("parse C#");
        let (classes, _, _) = extract_csharp_symbols(&tree, src);
        let r = classes.iter().find(|c| c.name == "Person").expect("record Person");
        assert_eq!(r.fqn, "N.Person");
        assert_eq!(r.kind, Some("record"));
    }

    #[test]
    fn csharp_namespace_nested_blocks_in_fqn() {
        let src = r#"
namespace A {
  namespace B {
    public class C {
      public void M() {}
    }
  }
}
"#;
        let tree = parse_once(LanguageId::CSharp, src).expect("parse C#");
        let (classes, methods, _) = extract_csharp_symbols(&tree, src);
        let c = classes.iter().find(|x| x.name == "C").expect("class C");
        assert_eq!(c.fqn, "A.B.C");
        let m = methods.iter().find(|f| f.name == "M").expect("method M");
        assert_eq!(m.fqn, "A.B.C.M");
    }

    #[test]
    fn csharp_namespace_file_scoped_extracts() {
        let src = "namespace Ns;\npublic class X { }\n";
        let tree = parse_once(LanguageId::CSharp, src).expect("parse C#");
        assert_eq!(
            extract_csharp_namespace(&tree, src).as_deref(),
            Some("Ns")
        );
        let (classes, _, _) = extract_csharp_symbols(&tree, src);
        let x = classes.iter().find(|c| c.name == "X").expect("class X");
        assert_eq!(x.fqn, "Ns.X");
    }

    #[test]
    fn csharp_collect_file_namespace_strings_two_roots() {
        let src = r#"
namespace A { public class Ca { } }
namespace B { public class Cb { } }
"#;
        let tree = parse_once(LanguageId::CSharp, src).expect("parse C#");
        let mut ns = collect_csharp_file_namespace_strings(&tree, src);
        ns.sort();
        assert_eq!(ns, vec!["A".to_string(), "B".to_string()]);
    }

    #[test]
    fn csharp_class_inheritance_edges_resolved() {
        let src_base = "namespace N { public class Base { } }";
        let src_der = "namespace N { public class Derived : Base { } }";
        let tree_b = parse_once(LanguageId::CSharp, src_base).expect("parse");
        let tree_d = parse_once(LanguageId::CSharp, src_der).expect("parse");
        let files = vec![
            ParsedFile {
                path: PathBuf::from("/b/Base.cs"),
                language: LanguageId::CSharp,
                tree: tree_b,
                source: src_base.to_string(),
                is_test: false,
            },
            ParsedFile {
                path: PathBuf::from("/d/Derived.cs"),
                language: LanguageId::CSharp,
                tree: tree_d,
                source: src_der.to_string(),
                is_test: false,
            },
        ];
        let index = build_csharp_batch_index(&files, Path::new("."));
        let using = extract_csharp_using_summary(&files[1].tree, &files[1].source);
        let edges = extract_csharp_class_inheritance_edges(
            &files[1].tree,
            &files[1].source,
            Some("N"),
            &using,
            &index,
        );
        assert!(
            edges.contains(&(String::from("N.Derived"), String::from("N.Base"))),
            "edges={edges:?}"
        );
    }

    #[test]
    fn csharp_symbols_constructor_function_matches_call_graph_fqn() {
        let src = r#"
namespace Ns {
  public class C {
    public C() { M(); }
    public void M() { }
  }
}
"#;
        let tree = parse_once(LanguageId::CSharp, src).expect("parse C#");
        let files = vec![ParsedFile {
            path: PathBuf::from("/t/C.cs"),
            language: LanguageId::CSharp,
            tree,
            source: src.to_string(),
            is_test: false,
        }];
        let index = build_csharp_batch_index(&files, Path::new("."));
        let using_summary = extract_csharp_using_summary(&files[0].tree, &files[0].source);
        let (_, methods, _) = extract_csharp_symbols(&files[0].tree, &files[0].source);
        let ctor = methods
            .iter()
            .find(|f| f.fqn == "Ns.C.ctor#0")
            .expect("ctor#0 symbol");
        assert_eq!(ctor.name, "ctor#0");
        assert_eq!(ctor.class_fqn.as_deref(), Some("Ns.C"));
        let calls = extract_csharp_calls(
            &files[0].tree,
            &files[0].source,
            Some("Ns"),
            &using_summary,
            &index,
        );
        assert!(
            calls.iter().any(|(a, b)| a == "Ns.C.ctor#0" && b == "Ns.C.M"),
            "expected persisted ctor fqn as caller, got {calls:?}"
        );
    }

    #[test]
    fn csharp_symbols_property_declares_accessors_and_property_symbol() {
        let src = r#"
namespace Ns {
  public class C {
    public string Name { get; set; }
  }
}
"#;
        let tree = parse_once(LanguageId::CSharp, src).expect("parse C#");
        let (_, methods, properties) = extract_csharp_symbols(&tree, src);
        let pname = properties.iter().find(|p| p.name == "Name").expect("property Name");
        assert_eq!(pname.fqn, "Ns.C.Name");
        assert_eq!(pname.class_fqn, "Ns.C");
        assert!(pname.declared_type.as_deref() == Some("string"));
        let get_f = methods
            .iter()
            .find(|f| f.fqn == "Ns.C.get_Name")
            .expect("getter function");
        assert_eq!(get_f.name, "get_Name");
        let set_f = methods
            .iter()
            .find(|f| f.fqn == "Ns.C.set_Name")
            .expect("setter function");
        assert_eq!(set_f.name, "set_Name");
    }

    #[test]
    fn csharp_symbols_method_modifiers_params_return_type() {
        let src = r#"
namespace N {
  public class Api {
    public static async System.Threading.Tasks.Task<int> Foo(string s, OrderDto o) { return 0; }
  }
}
"#;
        let tree = parse_once(LanguageId::CSharp, src).expect("parse C#");
        let (_, methods, _) = extract_csharp_symbols(&tree, src);
        let f = methods.iter().find(|m| m.name == "Foo").expect("Foo");
        assert!(f.modifiers.contains(&"public".to_string()));
        assert!(f.modifiers.contains(&"static".to_string()));
        assert!(f.modifiers.contains(&"async".to_string()));
        assert_eq!(f.param_count, 2);
        assert_eq!(f.param_types, vec!["string", "OrderDto"]);
        assert!(f.return_type.as_deref().unwrap_or("").contains("Task<int>"));
    }

    #[test]
    fn csharp_method_body_spans_nested_method_fqn() {
        let src = r#"
namespace N {
  public class Outer {
    public class Inner {
      public void M() { int x = 1; }
    }
  }
}
"#;
        let tree = parse_once(LanguageId::CSharp, src).expect("parse C#");
        let spans = csharp_method_body_spans(&tree, src, Some("N"));
        let m = spans.iter().find(|(fqn, _, _)| fqn.ends_with(".M")).expect("span M");
        assert_eq!(m.0, "N.Outer.Inner.M");
    }

    #[test]
    fn csharp_uses_class_resolves_type_via_using_and_batch_index() {
        let src_other = "namespace OtherNs { public class RemoteDto { } }\n";
        let src_consumer = r#"
using OtherNs;
namespace ConsumerNs {
  public class Consumer {
    public void M() {
      RemoteDto x;
    }
  }
}
"#;
        let tree_other = parse_once(LanguageId::CSharp, src_other).expect("parse");
        let tree_consumer = parse_once(LanguageId::CSharp, src_consumer).expect("parse");
        let files = vec![
            ParsedFile {
                path: PathBuf::from("/repo/OtherNs/RemoteDto.cs"),
                language: LanguageId::CSharp,
                tree: tree_other,
                source: src_other.to_string(),
                is_test: false,
            },
            ParsedFile {
                path: PathBuf::from("/repo/Consumer.cs"),
                language: LanguageId::CSharp,
                tree: tree_consumer,
                source: src_consumer.to_string(),
                is_test: false,
            },
        ];
        let index = build_csharp_batch_index(&files, Path::new("."));
        let using_summary = extract_csharp_using_summary(&files[1].tree, &files[1].source);
        let uses = extract_csharp_used_classes(
            &files[1].tree,
            &files[1].source,
            Some("ConsumerNs"),
            &using_summary,
            &index,
        );
        assert!(
            uses.iter().any(|(_, cls)| cls == "OtherNs.RemoteDto"),
            "expected USES_CLASS to OtherNs.RemoteDto, got {uses:?}"
        );
    }

    #[test]
    fn csharp_type_alias_using_resolves_to_aliased_class_fqn() {
        let src_other = "namespace OtherNs { public class RemoteDto { } }\n";
        let src_consumer = r#"
using R = OtherNs.RemoteDto;
namespace ConsumerNs {
  public class Consumer {
    public void M() {
      R x;
    }
  }
}
"#;
        let tree_other = parse_once(LanguageId::CSharp, src_other).expect("parse");
        let tree_consumer = parse_once(LanguageId::CSharp, src_consumer).expect("parse");
        let files = vec![
            ParsedFile {
                path: PathBuf::from("/p/Other.cs"),
                language: LanguageId::CSharp,
                tree: tree_other,
                source: src_other.to_string(),
                is_test: false,
            },
            ParsedFile {
                path: PathBuf::from("/p/Consumer.cs"),
                language: LanguageId::CSharp,
                tree: tree_consumer,
                source: src_consumer.to_string(),
                is_test: false,
            },
        ];
        let index = build_csharp_batch_index(&files, Path::new("."));
        let using_summary = extract_csharp_using_summary(&files[1].tree, &files[1].source);
        let uses = extract_csharp_used_classes(
            &files[1].tree,
            &files[1].source,
            Some("ConsumerNs"),
            &using_summary,
            &index,
        );
        assert!(uses.iter().any(|(_, cls)| cls == "OtherNs.RemoteDto"));
    }

    #[test]
    fn csharp_uses_class_does_not_use_method_name_as_type_from_invocation() {
        let src = r#"
namespace Ns {
  public class C {
    public void GetOrder() { }
    public void M() {
      var x = GetOrder();
    }
  }
}
"#;
        let tree = parse_once(LanguageId::CSharp, src).expect("parse");
        let files = vec![ParsedFile {
            path: PathBuf::from("/t/C.cs"),
            language: LanguageId::CSharp,
            tree,
            source: src.to_string(),
            is_test: false,
        }];
        let index = build_csharp_batch_index(&files, Path::new("."));
        let using_summary = extract_csharp_using_summary(&files[0].tree, &files[0].source);
        let uses = extract_csharp_used_classes(
            &files[0].tree,
            &files[0].source,
            Some("Ns"),
            &using_summary,
            &index,
        );
        assert!(
            !uses.iter().any(|(_, cls)| cls == "Ns.GetOrder"),
            "GetOrder() invocation must not create USES_CLASS to a synthetic type, got {uses:?}"
        );
    }

    #[test]
    fn csharp_uses_class_skips_bcl_datetime_in_parameter() {
        let src = r#"
namespace Ns {
  public class C {
    public void M(System.DateTime d) { }
  }
}
"#;
        let tree = parse_once(LanguageId::CSharp, src).expect("parse");
        let files = vec![ParsedFile {
            path: PathBuf::from("/t/C.cs"),
            language: LanguageId::CSharp,
            tree,
            source: src.to_string(),
            is_test: false,
        }];
        let index = build_csharp_batch_index(&files, Path::new("."));
        let using_summary = extract_csharp_using_summary(&files[0].tree, &files[0].source);
        let uses = extract_csharp_used_classes(
            &files[0].tree,
            &files[0].source,
            Some("Ns"),
            &using_summary,
            &index,
        );
        assert!(
            !uses.iter().any(|(_, cls)| cls.contains("DateTime")),
            "DateTime parameter should be filtered as BCL noise, got {uses:?}"
        );
    }

    #[test]
    fn csharp_uses_class_does_not_include_types_only_used_in_local_function() {
        let src = r#"
namespace Ns {
  public class Outer {
    public void M() {
      void Local() {
        InnerOnly x;
      }
    }
  }
  public class InnerOnly { }
}
"#;
        let tree = parse_once(LanguageId::CSharp, src).expect("parse");
        let files = vec![ParsedFile {
            path: PathBuf::from("/t/Types.cs"),
            language: LanguageId::CSharp,
            tree,
            source: src.to_string(),
            is_test: false,
        }];
        let index = build_csharp_batch_index(&files, Path::new("."));
        let using_summary = extract_csharp_using_summary(&files[0].tree, &files[0].source);
        let uses = extract_csharp_used_classes(
            &files[0].tree,
            &files[0].source,
            Some("Ns"),
            &using_summary,
            &index,
        );
        assert!(
            !uses
                .iter()
                .any(|(caller, cls)| caller == "Ns.Outer.M" && cls.contains("InnerOnly")),
            "InnerOnly only appears inside local function; outer M must not USES_CLASS it, got {uses:?}"
        );
    }

    #[test]
    fn csharp_calls_resolve_field_receiver_to_type_fqn() {
        let src_repo =
            "namespace OtherNs { public class OrderRepo { public void Get(int id) { } } }\n";
        let src_svc = r#"
using OtherNs;
namespace ConsumerNs {
  public class Svc {
    private OrderRepo _repo;
    public void M() { _repo.Get(1); }
  }
}
"#;
        let tree_repo = parse_once(LanguageId::CSharp, src_repo).expect("parse");
        let tree_svc = parse_once(LanguageId::CSharp, src_svc).expect("parse");
        let files = vec![
            ParsedFile {
                path: PathBuf::from("/r/OrderRepo.cs"),
                language: LanguageId::CSharp,
                tree: tree_repo,
                source: src_repo.to_string(),
                is_test: false,
            },
            ParsedFile {
                path: PathBuf::from("/r/Svc.cs"),
                language: LanguageId::CSharp,
                tree: tree_svc,
                source: src_svc.to_string(),
                is_test: false,
            },
        ];
        let index = build_csharp_batch_index(&files, Path::new("."));
        let using_summary = extract_csharp_using_summary(&files[1].tree, &files[1].source);
        let calls = extract_csharp_calls(
            &files[1].tree,
            &files[1].source,
            Some("ConsumerNs"),
            &using_summary,
            &index,
        );
        assert!(
            calls.iter().any(|(_, c)| c == "OtherNs.OrderRepo.Get"),
            "expected callee OtherNs.OrderRepo.Get, got {calls:?}"
        );
    }

    #[test]
    fn csharp_calls_this_receiver_resolves_to_class_method() {
        let src = r#"
namespace Ns {
  public class C {
    void Helper() { }
    public void Run() { this.Helper(); }
  }
}
"#;
        let tree = parse_once(LanguageId::CSharp, src).expect("parse");
        let files = vec![ParsedFile {
            path: PathBuf::from("/t/C.cs"),
            language: LanguageId::CSharp,
            tree,
            source: src.to_string(),
            is_test: false,
        }];
        let index = build_csharp_batch_index(&files, Path::new("."));
        let using_summary = extract_csharp_using_summary(&files[0].tree, &files[0].source);
        let calls = extract_csharp_calls(
            &files[0].tree,
            &files[0].source,
            Some("Ns"),
            &using_summary,
            &index,
        );
        assert!(
            calls.iter().any(|(_, c)| c == "Ns.C.Helper"),
            "expected callee Ns.C.Helper, got {calls:?}"
        );
    }

    #[test]
    fn csharp_calls_constructor_invocations_extracted() {
        let src = r#"
namespace Ns {
  public class C {
    public C() { M(); }
    public void M() { }
  }
}
"#;
        let tree = parse_once(LanguageId::CSharp, src).expect("parse");
        let files = vec![ParsedFile {
            path: PathBuf::from("/t/C.cs"),
            language: LanguageId::CSharp,
            tree,
            source: src.to_string(),
            is_test: false,
        }];
        let index = build_csharp_batch_index(&files, Path::new("."));
        let using_summary = extract_csharp_using_summary(&files[0].tree, &files[0].source);
        let calls = extract_csharp_calls(
            &files[0].tree,
            &files[0].source,
            Some("Ns"),
            &using_summary,
            &index,
        );
        assert!(
            calls.iter().any(|(a, b)| a == "Ns.C.ctor#0" && b == "Ns.C.M"),
            "expected ctor caller Ns.C.ctor#0 -> Ns.C.M, got {calls:?}"
        );
    }

    #[test]
    fn csharp_calls_property_getter_invocations_extracted() {
        let src = r#"
namespace Ns {
  public class C {
    public int Prop {
      get { Helper(); return 1; }
    }
    void Helper() { }
  }
}
"#;
        let tree = parse_once(LanguageId::CSharp, src).expect("parse");
        let files = vec![ParsedFile {
            path: PathBuf::from("/t/C.cs"),
            language: LanguageId::CSharp,
            tree,
            source: src.to_string(),
            is_test: false,
        }];
        let index = build_csharp_batch_index(&files, Path::new("."));
        let using_summary = extract_csharp_using_summary(&files[0].tree, &files[0].source);
        let calls = extract_csharp_calls(
            &files[0].tree,
            &files[0].source,
            Some("Ns"),
            &using_summary,
            &index,
        );
        assert!(
            calls.iter().any(|(a, b)| a == "Ns.C.get_Prop" && b == "Ns.C.Helper"),
            "expected getter caller Ns.C.get_Prop -> Ns.C.Helper, got {calls:?}"
        );
    }

    #[test]
    fn csharp_calls_console_writeline_uses_well_known_type() {
        let src = r#"
namespace Ns {
  public class C {
    public void M() { Console.WriteLine("x"); }
  }
}
"#;
        let tree = parse_once(LanguageId::CSharp, src).expect("parse");
        let files = vec![ParsedFile {
            path: PathBuf::from("/t/C.cs"),
            language: LanguageId::CSharp,
            tree,
            source: src.to_string(),
            is_test: false,
        }];
        let index = build_csharp_batch_index(&files, Path::new("."));
        let using_summary = extract_csharp_using_summary(&files[0].tree, &files[0].source);
        let calls = extract_csharp_calls(
            &files[0].tree,
            &files[0].source,
            Some("Ns"),
            &using_summary,
            &index,
        );
        assert!(
            calls.iter().any(|(_, c)| c == "System.Console.WriteLine"),
            "expected System.Console.WriteLine, got {calls:?}"
        );
    }

    #[test]
    fn csharp_external_http_urls_ignore_comments_not_string_literals() {
        let src = r#"
namespace Ns {
  class C {
    // https://evil-line.example/x
    void M() {
      /* https://evil-block.example/y */
      var x = "https://good.example/only";
    }
  }
}
"#;
        let tree = parse_once(LanguageId::CSharp, src).expect("parse C#");
        let urls = extract_csharp_external_http_urls_with_spans(&tree, src);
        assert_eq!(urls.len(), 1, "expected one URL from string literal, got {urls:?}");
        assert!(
            urls[0].0.contains("good.example"),
            "unexpected url {:?}",
            urls[0].0
        );
        assert!(
            !urls.iter().any(|(u, _, _)| u.contains("evil")),
            "comment URLs must not appear: {urls:?}"
        );
    }

    #[test]
    fn csharp_external_api_links_url_only_to_methods_whose_body_contains_literal() {
        let src = r#"
namespace Ns {
  public class C {
    void A() { var x = "https://api-a.example/v1"; }
    void B() { var y = "https://api-b.example/v2"; }
  }
}
"#;
        let tree = parse_once(LanguageId::CSharp, src).expect("parse C#");
        let (_, methods, _) = extract_csharp_symbols(&tree, src);
        let url_spans = extract_csharp_external_http_urls_with_spans(&tree, src);
        let method_spans = csharp_method_body_spans(&tree, src, Some("Ns"));
        let mut spans_by_fqn: HashMap<String, Vec<(usize, usize)>> = HashMap::new();
        for (fqn, lo, hi) in method_spans {
            spans_by_fqn.entry(fqn).or_default().push((lo, hi));
        }
        let mut pairs: Vec<(String, String)> = Vec::new();
        for (full_url, u_start, u_end) in &url_spans {
            for func in &methods {
                let Some(ranges) = spans_by_fqn.get(&func.fqn) else {
                    continue;
                };
                if !ranges
                    .iter()
                    .any(|(lo, hi)| *lo <= *u_start && *u_end <= *hi)
                {
                    continue;
                }
                pairs.push((func.fqn.clone(), full_url.clone()));
            }
        }
        pairs.sort();
        assert!(
            pairs.contains(&(String::from("Ns.C.A"), String::from("https://api-a.example/v1"))),
            "missing A->api-a, got {pairs:?}"
        );
        assert!(
            pairs.contains(&(String::from("Ns.C.B"), String::from("https://api-b.example/v2"))),
            "missing B->api-b, got {pairs:?}"
        );
        assert!(
            !pairs.contains(&(String::from("Ns.C.A"), String::from("https://api-b.example/v2"))),
            "N×M leak: A linked to B's URL: {pairs:?}"
        );
        assert!(
            !pairs.contains(&(String::from("Ns.C.B"), String::from("https://api-a.example/v1"))),
            "N×M leak: B linked to A's URL: {pairs:?}"
        );
    }

    #[test]
    fn resolves_module_name_from_erl_attribute() {
        let source = "-module(real_mod).\nfoo() -> ok.\n";
        let tree = parse_once(LanguageId::Erlang, source).expect("Erlang parse should succeed");
        let resolved = resolve_erlang_module_name(Path::new("/tmp/not_matching.erl"), &tree, source);
        assert_eq!(resolved.as_deref(), Some("real_mod"));
    }
    //Fallback to file basename for .erl when attribute is missing

    #[test]
    fn resolves_module_name_from_erl_basename_fallback() {
        let source = "foo() -> ok.\n";
        let tree = parse_once(LanguageId::Erlang, source).expect("Erlang parse should succeed");
        let resolved = resolve_erlang_module_name(Path::new("/tmp/fallback_name.erl"), &tree, source);
        assert_eq!(resolved.as_deref(), Some("fallback_name"));
    }
    //No fallback for .hrl files (returns None)
    #[test]
    fn does_not_fallback_module_name_for_hrl() {
        let source = "-define(FLAG, true).\n";
        let tree = parse_once(LanguageId::Erlang, source).expect("Erlang parse should succeed");
        let resolved = resolve_erlang_module_name(Path::new("/tmp/records.hrl"), &tree, source);
        assert_eq!(resolved, None);
    }

    #[test]
    fn extracts_erlang_behaviour_usages_from_ast() {
        let source = r#"
            -behaviour(gen_server).
            -behavior(custom_behaviour).
            foo() -> ok.
        "#;
        let tree = parse_once(LanguageId::Erlang, source).expect("Erlang parse should succeed");
        let meta = extract_erlang_behaviour_metadata_from_tree(&tree, source);
        assert!(meta.behaviour_usages.contains("gen_server"));
        assert!(meta.behaviour_usages.contains("custom_behaviour"));
    }

    #[test]
    fn extracts_declared_and_optional_callbacks_from_ast() {
        let source = r#"
            -callback init(term()) -> {ok, state()}.
            -callback handle_call(term(), term(), term()) -> {reply, ok, term()}.
            -optional_callbacks([handle_call/3]).
        "#;
        let tree = parse_once(LanguageId::Erlang, source).expect("Erlang parse should succeed");
        let meta = extract_erlang_behaviour_metadata_from_tree(&tree, source);

        assert!(meta.declared_callbacks.contains(&(String::from("init"), 1)));
        assert!(
            meta.declared_callbacks
                .contains(&(String::from("handle_call"), 3))
        );
        assert!(
            meta.optional_callbacks
                .contains(&(String::from("handle_call"), 3))
        );
        assert!(!meta.optional_callbacks.contains(&(String::from("init"), 1)));
    }

    #[test]
    fn extracts_behaviour_extension_and_override_hints_from_ast() {
        let source = r#"
            -extends_behaviour(base_handler).
            -override_callback(handle_call/3).
        "#;
        let tree = parse_once(LanguageId::Erlang, source).expect("Erlang parse should succeed");
        let meta = extract_erlang_behaviour_metadata_from_tree(&tree, source);
        assert!(meta.behaviour_extensions.contains("base_handler"));
        assert!(
            meta.overridden_callbacks
                .contains(&(String::from("handle_call"), 3))
        );
    }

    #[test]
    fn ast_extracts_multiline_and_quoted_attributes() {
        let source = r#"
            -'behaviour'('gen_server').
            -callback
                'handle_call'(
                    term(),
                    term(),
                    term()
                ) ->
                    {reply, ok, term()}.
            -optional_callbacks([
                'handle_call'/3
            ]).
        "#;
        let tree = parse_once(LanguageId::Erlang, source).expect("Erlang parse should succeed");
        let meta = extract_erlang_behaviour_metadata_from_tree(&tree, source);
        assert!(meta.behaviour_usages.contains("gen_server"));
        assert!(
            meta.declared_callbacks
                .contains(&(String::from("handle_call"), 3))
        );
        assert!(
            meta.optional_callbacks
                .contains(&(String::from("handle_call"), 3))
        );
    }

    #[test]
    fn ast_skips_macro_or_variable_names_for_safety() {
        let source = r#"
            -behaviour(?DYN_BEHAVIOUR).
            -optional_callbacks([?CALLBACK/2]).
            -extends_behaviour(ParentVar).
            -override_callback(?OVERRIDE/3).
        "#;
        let tree = parse_once(LanguageId::Erlang, source).expect("Erlang parse should succeed");
        let meta = extract_erlang_behaviour_metadata_from_tree(&tree, source);
        assert!(meta.behaviour_usages.is_empty());
        assert!(meta.optional_callbacks.is_empty());
        assert!(meta.behaviour_extensions.is_empty());
        assert!(meta.overridden_callbacks.is_empty());
    }

    #[test]
    fn maps_functions_to_callback_contracts() {
        let source = r#"
            -behaviour(gen_server).
            -callback local_cb(term()) -> ok.
            -optional_callbacks([local_cb/1]).
            init(Args) -> {ok, Args}.
            handle_call(_Req, _From, State) -> {reply, ok, State}.
            local_cb(X) -> X.
        "#;
        let tree = parse_once(LanguageId::Erlang, source).expect("Erlang parse should succeed");
        let meta = extract_erlang_behaviour_metadata_from_tree(&tree, source);
        let contracts = collect_callback_contracts_for_module(
            Some("my_behaviour"),
            &meta.behaviour_usages,
            &meta.declared_callbacks,
            &meta.optional_callbacks,
        );

        // OTP known callback from gen_server.
        assert!(contracts.iter().any(|c| {
            c.behaviour == "gen_server" && c.name == "handle_call" && c.arity == 3
        }));
        // Local declared callback + optional=true.
        assert!(contracts.iter().any(|c| {
            c.behaviour == "my_behaviour"
                && c.name == "local_cb"
                && c.arity == 1
                && c.optional
        }));
    }

    #[test]
    fn extracts_erlang_functions_from_ast_multiline_and_quoted() {
        let source = r#"
            -module(my_handler).
            'special_name'(
                Req,
                State
            ) ->
                {ok, State}.
            websocket_handle(Frame, State) ->
                {ok, State}.
        "#;
        let tree = parse_once(LanguageId::Erlang, source).expect("Erlang parse should succeed");
        let functions = extract_erlang_functions("my_handler", &tree, source);
        let sigs: HashSet<(String, u32)> = functions
            .iter()
            .map(|(name, arity, _)| (name.clone(), *arity))
            .collect();

        assert!(sigs.contains(&(String::from("special_name"), 2)));
        assert!(sigs.contains(&(String::from("websocket_handle"), 2)));
    }

    #[test]
    fn erlang_function_spans_keyed_by_fqn() {
        let source = r#"
-module(m).
handle(Req, State) ->
    {ok, State}.
"#;
        let tree = parse_once(LanguageId::Erlang, source).expect("parse");
        let spans = extract_erlang_function_spans("m", &tree, source);
        let fqn = "m:handle/2";
        let (lo, hi) = spans.get(fqn).copied().expect("span for handle/2");
        assert!(source[lo..hi].contains("handle(Req, State)"));
    }

    #[test]
    fn java_method_body_spans_include_method_body() {
        let source = r#"
package com.example;
class A {
  void m() { return; }
}
"#;
        let tree = parse_once(LanguageId::Java, source).expect("parse");
        let spans = extract_java_method_body_spans(&tree, source, Some("com.example"));
        let (lo, hi) = spans.get("com.example.A.m").copied().expect("span");
        assert!(source[lo..hi].contains("return"));
    }

    #[test]
    fn selects_endpoint_handler_callbacks_from_contracts_and_implemented_signatures() {
        let mut idx = HashMap::new();
        idx.insert(
            String::from("omega_ws_handler"),
            ErlangModuleSnapshot {
                implemented_signatures: HashSet::from([
                    (String::from("init"), 2),
                    (String::from("websocket_handle"), 2),
                    (String::from("not_a_callback"), 1),
                ]),
                callback_signatures: HashSet::from([
                    (String::from("init"), 2),
                    (String::from("websocket_handle"), 2),
                    (String::from("websocket_info"), 2),
                ]),
            },
        );

        let fqns = select_endpoint_handler_fqns("omega_ws_handler", &idx);
        assert_eq!(
            fqns,
            vec![
                String::from("omega_ws_handler:init/2"),
                String::from("omega_ws_handler:websocket_handle/2"),
            ]
        );
    }

    #[test]
    fn endpoint_handler_callback_selection_is_strict_when_metadata_missing() {
        let mut idx = HashMap::new();
        idx.insert(
            String::from("router_only"),
            ErlangModuleSnapshot {
                implemented_signatures: HashSet::from([(String::from("init"), 2)]),
                callback_signatures: HashSet::new(),
            },
        );

        let none_for_unknown = select_endpoint_handler_fqns("missing_module", &idx);
        assert!(none_for_unknown.is_empty());

        let none_for_no_contracts = select_endpoint_handler_fqns("router_only", &idx);
        assert!(none_for_no_contracts.is_empty());
    }

    #[test]
    fn extracts_precise_erlang_call_edges_from_ast() {
        let source = r#"
            -module(my_mod).
            a() -> b(), c(), ok.
            b() -> ok.
            c() -> lists:map(fun(X) -> X end, [1,2]).
        "#;
        let tree = parse_once(LanguageId::Erlang, source).expect("Erlang parse should succeed");
        let functions = extract_erlang_functions("my_mod", &tree, source);
        let function_by_sig: HashMap<(String, u32), String> = functions
            .iter()
            .map(|(name, arity, fqn)| ((name.clone(), *arity), fqn.clone()))
            .collect();
        let edges = extract_erlang_call_edges(&tree, source, Some("my_mod"), &function_by_sig);

        assert!(edges.contains(&(String::from("my_mod:a/0"), String::from("my_mod:b/0"))));
        assert!(edges.contains(&(String::from("my_mod:a/0"), String::from("my_mod:c/0"))));
        // Remote stdlib call should not become intra-module edge.
        assert!(!edges.contains(&(String::from("my_mod:c/0"), String::from("my_mod:map/2"))));
    }

    #[test]
    fn does_not_create_nm_edges_for_sparse_local_calls() {
        let source = r#"
            -module(my_mod).
            a() -> b().
            b() -> ok.
            c() -> ok.
            d() -> ok.
        "#;
        let tree = parse_once(LanguageId::Erlang, source).expect("Erlang parse should succeed");
        let functions = extract_erlang_functions("my_mod", &tree, source);
        let function_by_sig: HashMap<(String, u32), String> = functions
            .iter()
            .map(|(name, arity, fqn)| ((name.clone(), *arity), fqn.clone()))
            .collect();
        let edges = extract_erlang_call_edges(&tree, source, Some("my_mod"), &function_by_sig);

        let expected = HashSet::from([(String::from("my_mod:a/0"), String::from("my_mod:b/0"))]);
        assert_eq!(edges, expected);
    }

    #[test]
    fn attributes_calls_to_enclosing_multi_clause_function() {
        let source = r#"
            -module(my_mod).
            foo(0) -> bar();
            foo(N) -> baz(N).
            bar() -> ok.
            baz(_N) -> ok.
        "#;
        let tree = parse_once(LanguageId::Erlang, source).expect("Erlang parse should succeed");
        let functions = extract_erlang_functions("my_mod", &tree, source);
        let function_by_sig: HashMap<(String, u32), String> = functions
            .iter()
            .map(|(name, arity, fqn)| ((name.clone(), *arity), fqn.clone()))
            .collect();
        let edges = extract_erlang_call_edges(&tree, source, Some("my_mod"), &function_by_sig);

        assert!(edges.contains(&(String::from("my_mod:foo/1"), String::from("my_mod:bar/0"))));
        assert!(edges.contains(&(String::from("my_mod:foo/1"), String::from("my_mod:baz/1"))));
        assert_eq!(edges.len(), 2);
    }

    #[test]
    fn extracts_called_modules_from_ast_remote_calls() {
        let source = r#"
            -module(my_mod).
            a() -> lists:map(fun(X) -> X end, [1,2]), my_dep:run().
        "#;
        let tree = parse_once(LanguageId::Erlang, source).expect("Erlang parse should succeed");
        let mods = extract_erlang_called_modules_from_tree(&tree, source);
        assert!(mods.contains("lists"));
        assert!(mods.contains("my_dep"));
    }

    #[test]
    fn extracts_cowboy_endpoints_from_ast_multiline_tuples() {
        let source = r#"
            Dispatch = cowboy_router:compile([
                {'_', [
                    {"/v1/ping", ping_handler, []},
                    {
                        "/v1/ws",
                        websocket_handler,
                        []
                    }
                ]}
            ]).
        "#;
        let tree = parse_once(LanguageId::Erlang, source).expect("Erlang parse should succeed");
        let endpoints = extract_erlang_api_endpoints(&tree, source);
        let keyset: HashSet<(String, String)> = endpoints
            .into_iter()
            .map(|(_, path, handler)| (path, handler))
            .collect();
        assert!(keyset.contains(&(String::from("/v1/ping"), String::from("ping_handler"))));
        assert!(keyset.contains(&(String::from("/v1/ws"), String::from("websocket_handler"))));
    }

    #[test]
    fn extracts_external_urls_from_ast_strings_only() {
        let source = r#"
            -module(my_mod).
            a() ->
                Url = "https://api.example.com/v1/orders?x=1",
                io:format("~p", [Url]).
            % "https://comment.only/should/not/appear"
        "#;
        let tree = parse_once(LanguageId::Erlang, source).expect("Erlang parse should succeed");
        let urls = extract_external_http_urls_from_tree(&tree, source);
        assert!(urls.contains(&String::from("https://api.example.com/v1/orders?x=1")));
        assert!(!urls.iter().any(|u| u.contains("comment.only")));
    }

    // --- Java / Go CRM-3647–3656 extraction tests (no Neo4j) ---

    #[test]
    fn java_parse_warnings_surface_error_nodes() {
        let src = r#"
package p;
class Broken { void m(  // missing close paren and brace
"#;
        let tree = parse_once(LanguageId::Java, src).expect("parse");
        let w = extract_java_parse_warnings(&tree, src);
        assert!(
            !w.is_empty(),
            "expected ERROR/missing warnings, got {w:?}"
        );
        assert!(w.iter().any(|(line, _, _)| *line >= 2), "got {w:?}");
    }

    #[test]
    fn java_method_extracts_return_and_param_types() {
        let src = r#"
package com.example;
import java.util.List;
import org.springframework.http.ResponseEntity;
class Order {}
class C {
  public ResponseEntity<List<Order>> getOrders(String id, int page) { return null; }
}
"#;
        let tree = parse_once(LanguageId::Java, src).expect("parse");
        let (_, methods) = extract_java_symbols(&tree, src, Some("com.example"));
        let m = methods
            .iter()
            .find(|f| f.name == "getOrders")
            .expect("getOrders");
        assert_eq!(m.return_type.as_deref(), Some("ResponseEntity"));
        assert_eq!(m.param_types, vec!["String", "int"]);
        assert_eq!(m.param_count, 2);
    }

    #[test]
    fn java_inheritance_edges_extends_and_implements() {
        let src = r#"
package p;
class Parent {}
class Child extends Parent implements java.io.Serializable {}
"#;
        let tree = parse_once(LanguageId::Java, src).expect("parse");
        let edges = extract_java_inheritance_edges(&tree, src, Some("p"));
        assert!(edges.contains(&(String::from("p.Child"), String::from("p.Parent"))));
        assert!(edges.contains(&(
            String::from("p.Child"),
            String::from("java.io.Serializable")
        )));
    }

    #[test]
    fn java_class_and_method_annotations_extracted() {
        let src = r#"
package p;
@Service
class Svc {
  @Override
  @Deprecated
  void run() {}
}
"#;
        let tree = parse_once(LanguageId::Java, src).expect("parse");
        let c = extract_java_class_annotations(&tree, src, Some("p"));
        assert!(c.iter().any(|(fqn, a)| fqn == "p.Svc" && a.contains(&String::from("Service"))));
        let m = extract_java_method_annotations(&tree, src, Some("p"));
        let (_, anns) = m.iter().find(|(f, _)| f.ends_with(".run")).expect("run");
        assert!(anns.contains(&String::from("Override")));
        assert!(anns.contains(&String::from("Deprecated")));
    }

    #[test]
    fn java_injected_dependencies_constructor_and_autowired_field() {
        let src = r#"
package p;
class OrderRepo {}
class UserService {}
class MyService {
  @Autowired
  OrderRepo repo;
  public MyService(UserService svc, OrderRepo r2) {}
}
"#;
        let tree = parse_once(LanguageId::Java, src).expect("parse");
        let deps = extract_java_injected_dependencies(&tree, src, Some("p"));
        assert!(deps.contains(&(String::from("p.MyService"), String::from("p.OrderRepo"))));
        assert!(deps.contains(&(String::from("p.MyService"), String::from("p.UserService"))));
    }

    #[test]
    fn go_parse_warnings_surface_error_nodes() {
        let src = r#"package main
func main() { x := 
"#;
        let tree = parse_once(LanguageId::Go, src).expect("parse");
        let w = extract_go_parse_warnings(&tree, src);
        assert!(!w.is_empty(), "expected warnings, got {w:?}");
    }

    #[test]
    fn go_extracts_interface_kind_and_struct_embedding() {
        let src = r#"package main
import "io"
type Reader interface { Read(p []byte) (n int, err error) }
type MyStruct struct {
	io.Reader
	Name string
}
"#;
        let tree = parse_once(LanguageId::Go, src).expect("parse");
        let (classes, _) = extract_go_symbols(&tree, src, Some("main"));
        assert!(classes.iter().any(|c| c.name == "Reader" && c.kind == Some("interface")));
        assert!(classes.iter().any(|c| c.name == "MyStruct" && c.kind == Some("struct")));
        let emb = extract_go_embedding(&tree, src, Some("main"));
        assert!(emb.contains(&(String::from("main.MyStruct"), String::from("io.Reader"))));
    }

    #[test]
    fn go_goroutine_call_extracted_as_calls_function_pair() {
        let src = r#"package main
func worker() {}
func main() { go worker() }
"#;
        let tree = parse_once(LanguageId::Go, src).expect("parse");
        let g = extract_go_goroutine_calls(&tree, src, Some("main"));
        assert!(
            g.contains(&(String::from("main.main"), String::from("main.worker"))),
            "got {g:?}"
        );
    }

    #[test]
    fn go_method_pointer_receiver_flag() {
        let src = r#"package main
type User struct{}
func (u *User) GetName() string { return "" }
func (u User) String() string { return "" }
"#;
        let tree = parse_once(LanguageId::Go, src).expect("parse");
        let (_, funcs) = extract_go_symbols(&tree, src, Some("main"));
        let get = funcs.iter().find(|f| f.name == "GetName").expect("GetName");
        assert_eq!(get.is_pointer_receiver, Some(true));
        let s = funcs.iter().find(|f| f.name == "String").expect("String");
        assert_eq!(s.is_pointer_receiver, Some(false));
    }

    #[test]
    fn go_import_paths_extracted_from_grouped_import() {
        let src = r#"package main
import (
  "fmt"
  "github.com/gorilla/mux"
  "myproject/internal/handler"
)
func main() {}
"#;
        let tree = parse_once(LanguageId::Go, src).expect("parse");
        let imps = extract_go_imports(&tree, src);
        assert!(imps.contains(&String::from("fmt")));
        assert!(imps.contains(&String::from("github.com/gorilla/mux")));
        assert!(imps.contains(&String::from("myproject/internal/handler")));
    }

    #[test]
    fn go_import_resolves_to_known_scanned_file_path() {
        let mut known = HashSet::new();
        known.insert(String::from("/repo/myproject/internal/handler/api.go"));
        let dep =
            resolve_go_import_to_known_go_file("myproject/internal/handler", &known, &[], &[], None);
        assert_eq!(dep.as_deref(), Some("/repo/myproject/internal/handler/api.go"));
    }

    #[test]
    fn rust_graph_symbols_use_file_scoped_fqn() {
        let src = "fn hello() {}";
        let tree = parse_once(LanguageId::Rust, src).expect("parse");
        let file = ParsedFile {
            path: PathBuf::from("/x/a.rs"),
            language: LanguageId::Rust,
            tree,
            source: src.to_string(),
            is_test: false,
        };
        let syms = extract_non_java_function_symbols(&file, src, "/x/a.rs");
        assert_eq!(syms.len(), 1);
        assert_eq!(syms[0].fqn, "/x/a.rs::hello");
    }

    #[test]
    fn rust_ir_emits_intrafile_calls() {
        let src = r#"
fn callee() {}
fn caller() {
    callee();
}
"#;
        let tree = parse_once(LanguageId::Rust, src).expect("parse");
        let files = vec![ParsedFile {
            path: PathBuf::from("src/a.rs"),
            language: LanguageId::Rust,
            tree,
            source: src.to_string(),
            is_test: false,
        }];
        let ir = build_project_ir(Path::new("/repo"), &files, &ExtractOptions::default());
        let has_call = ir.edges.iter().any(|e| {
            e.kind == EdgeKind::CallsFunction
                && e.from_key == "src/a.rs::caller"
                && e.to_key == "src/a.rs::callee"
        });
        assert!(has_call, "expected intra-file CALLS_FUNCTION");
    }

    #[test]
    fn rust_ir_emits_depends_on_file_from_use() {
        let caller_src = "use crate::other;\nfn caller() {}";
        let callee_src = "pub fn callee() {}";
        let caller_tree = parse_once(LanguageId::Rust, caller_src).expect("parse");
        let callee_tree = parse_once(LanguageId::Rust, callee_src).expect("parse");
        let files = vec![
            ParsedFile {
                path: PathBuf::from("src/caller.rs"),
                language: LanguageId::Rust,
                tree: caller_tree,
                source: caller_src.to_string(),
                is_test: false,
            },
            ParsedFile {
                path: PathBuf::from("src/other.rs"),
                language: LanguageId::Rust,
                tree: callee_tree,
                source: callee_src.to_string(),
                is_test: false,
            },
        ];
        let ir = build_project_ir(Path::new("/repo"), &files, &ExtractOptions::default());
        let has_dep = ir.edges.iter().any(|e| {
            e.kind == EdgeKind::DependsOnFile
                && e.from_key == "src/caller.rs"
                && e.to_key == "src/other.rs"
        });
        assert!(has_dep, "expected DEPENDS_ON_FILE from use crate::other");
    }

    #[test]
    fn go_ir_emits_calls_function_edges() {
        let src = r#"
package main

import "fmt"

func helper() { fmt.Println("x") }

func main() { helper() }
"#;
        let tree = parse_once(LanguageId::Go, src).expect("parse");
        let files = vec![ParsedFile {
            path: PathBuf::from("main.go"),
            language: LanguageId::Go,
            tree,
            source: src.to_string(),
            is_test: false,
        }];
        let ir = build_project_ir(Path::new("/repo"), &files, &ExtractOptions::default());
        let has_call = ir.edges.iter().any(|e| e.kind == EdgeKind::CallsFunction);
        assert!(has_call, "expected at least one CALLS_FUNCTION edge for Go");
    }

    #[test]
    fn python_graph_symbols_file_scoped_fqn_and_nested() {
        let src = r#"
def top():
    pass
def outer():
    def inner():
        pass
    pass
"#;
        let tree = parse_once(LanguageId::Python, src).expect("parse");
        let file = ParsedFile {
            path: PathBuf::from("/app/mod.py"),
            language: LanguageId::Python,
            tree,
            source: src.to_string(),
            is_test: false,
        };
        let syms = extract_non_java_function_symbols(&file, src, "/app/mod.py");
        let fqns: Vec<&str> = syms.iter().map(|s| s.fqn.as_str()).collect();
        assert!(fqns.contains(&"/app/mod.py::top"));
        assert!(fqns.contains(&"/app/mod.py::outer"));
        assert!(fqns.contains(&"/app/mod.py::outer.inner"));
    }

    #[test]
    fn python_class_methods_excluded_from_graph_symbols() {
        let src = r#"
class C:
    def meth(self):
        pass
def global_fn():
    pass
"#;
        let tree = parse_once(LanguageId::Python, src).expect("parse");
        let file = ParsedFile {
            path: PathBuf::from("/app/c.py"),
            language: LanguageId::Python,
            tree,
            source: src.to_string(),
            is_test: false,
        };
        let syms = extract_non_java_function_symbols(&file, src, "/app/c.py");
        assert!(!syms.iter().any(|s| s.name == "meth"));
        assert!(syms.iter().any(|s| s.name == "global_fn"));
    }

    #[test]
    fn js_graph_symbols_class_method_arrow_and_top_level() {
        let src = r#"
class Box {
  run() { return 1; }
  go = () => 2;
}
const top = () => {};
function decl() {}
"#;
        let tree = parse_once(LanguageId::JavaScript, src).expect("parse");
        let file = ParsedFile {
            path: PathBuf::from("/app/box.js"),
            language: LanguageId::JavaScript,
            tree,
            source: src.to_string(),
            is_test: false,
        };
        let syms = extract_non_java_function_symbols(&file, src, "/app/box.js");
        let fqns: Vec<&str> = syms.iter().map(|s| s.fqn.as_str()).collect();
        assert!(
            fqns.iter().any(|f| f.ends_with("::Box.run")),
            "got {fqns:?}"
        );
        assert!(
            fqns.iter().any(|f| f.ends_with("::Box.go")),
            "got {fqns:?}"
        );
        assert!(fqns.iter().any(|f| f.ends_with("::top")), "got {fqns:?}");
        assert!(fqns.iter().any(|f| f.ends_with("::decl")), "got {fqns:?}");
    }

    #[test]
    fn ts_graph_symbols_include_class_method() {
        let src = r#"
class Svc {
  handle(): void {}
}
"#;
        let tree = parse_once(LanguageId::TypeScript, src).expect("parse");
        let file = ParsedFile {
            path: PathBuf::from("/svc/h.ts"),
            language: LanguageId::TypeScript,
            tree,
            source: src.to_string(),
            is_test: false,
        };
        let syms = extract_non_java_function_symbols(&file, src, "/svc/h.ts");
        assert!(
            syms.iter().any(|s| s.fqn.ends_with("::Svc.handle")),
            "got {:?}",
            syms.iter().map(|s| &s.fqn).collect::<Vec<_>>()
        );
    }

    #[test]
    fn python_parse_warnings_surface_error_nodes() {
        let src = "def foo(\n";
        let tree = parse_once(LanguageId::Python, src).expect("parse");
        let w = extract_python_parse_warnings(&tree, src);
        assert!(!w.is_empty(), "expected warnings, got {w:?}");
    }

    #[test]
    fn js_parse_warnings_surface_error_nodes() {
        let src = "function f( {";
        let tree = parse_once(LanguageId::JavaScript, src).expect("parse");
        let w = extract_js_ts_parse_warnings(&tree, src);
        assert!(!w.is_empty(), "expected warnings, got {w:?}");
    }

    #[test]
    fn python_import_resolves_to_known_py_file() {
        let mut known = HashSet::new();
        known.insert("/repo/pkg/helper.py".to_string());
        let dep = resolve_python_import_to_known_file("pkg.helper", &known);
        assert_eq!(dep.as_deref(), Some("/repo/pkg/helper.py"));
    }

    #[test]
    fn python_intrafile_call_edge() {
        let src = r#"
def callee():
    pass
def caller():
    callee()
"#;
        let tree = parse_once(LanguageId::Python, src).expect("parse");
        let fp = "/t/a.py";
        let mut name_to_fqn = HashMap::new();
        name_to_fqn.insert("callee".into(), format!("{fp}::callee"));
        name_to_fqn.insert("caller".into(), format!("{fp}::caller"));
        let calls = extract_python_intrafile_calls(&tree, src, fp, &name_to_fqn);
        assert!(
            calls.contains(&(format!("{fp}::caller"), format!("{fp}::callee"))),
            "got {calls:?}"
        );
    }

    #[test]
    fn js_ts_relative_import_resolves_to_known_file() {
        let mut known = HashSet::new();
        known.insert("/repo/src/util.ts".to_string());
        let dep = resolve_js_ts_import_to_known_file("./util", "/repo/src/main.ts", &known);
        assert_eq!(dep.as_deref(), Some("/repo/src/util.ts"));
    }

    #[test]
    fn js_intrafile_call_edge() {
        let src = r#"
function callee() {}
function caller() { callee(); }
"#;
        let tree = parse_once(LanguageId::JavaScript, src).expect("parse");
        let fp = "/t/b.js";
        let mut name_to_fqn = HashMap::new();
        name_to_fqn.insert("callee".into(), format!("{fp}::callee"));
        name_to_fqn.insert("caller".into(), format!("{fp}::caller"));
        let calls = extract_js_ts_intrafile_calls(
            &tree,
            src,
            fp,
            LanguageId::JavaScript,
            &name_to_fqn,
        );
        assert!(
            calls.contains(&(format!("{fp}::caller"), format!("{fp}::callee"))),
            "got {calls:?}"
        );
    }
}