ryo-analysis 0.1.0

//! AnalysisContext - Unified initialization for code analysis structures.
//!
//! Provides a single entry point for constructing SymbolRegistry, CodeGraphV2,
//! and optionally DataFlowGraph from source files.
//!
//! # Example
//!
//! ```ignore
//! use ryo_analysis::AnalysisContext;
//!
//! // Production: Use from_workspace_root (recommended)
//! let ctx = AnalysisContext::from_workspace_root("/path/to/project")?;
//!
//! // Access components
//! let symbol = ctx.registry.lookup(&path);
//! let callers = ctx.code_graph.callers_of(symbol_id);
//! ```

use std::collections::HashMap;
use std::path::Path;
use std::sync::Arc;

use crate::import_map_builder::{build_import_map, collect_public_reexports};
use crate::SymbolKind;
use rayon::prelude::*;
use ryo_source::pure::{
    PureBlock, PureExpr, PureFields, PureFile, PureFn, PureImpl, PureImplItem, PureItem, PureStmt,
    PureTraitItem, PureVis,
};
use ryo_symbol::{
    CargoMetadataProvider, FileSpan, SymbolPathResolver, UseResolver, WorkspaceFilePath,
    WorkspacePathResolver,
};

use crate::ast::ASTRegistry;
use crate::detail_store::DetailStore;
use crate::query::{
    CodeEdgeV2, CodeGraphV2, DataFlowBuilderWorkspace, DataFlowGraphV2, TypeFlowBuilderV2,
    TypeFlowGraphV2,
};
use crate::symbol::{
    RegistryUpdate, RegistryUpdateBatch, SymbolId, SymbolPath, SymbolRegistry, Visibility,
};

/// Persistent HashMap with O(log n) clone via structural sharing.
pub type ImHashMap<K, V> = im::HashMap<K, V>;

/// Error type for AnalysisContext operations.
#[derive(Debug, thiserror::Error)]
pub enum ContextError {
    /// Failure originating from `cargo metadata` or workspace metadata
    /// resolution. Carries a rendered message for diagnostics.
    #[error("Metadata error: {0}")]
    Metadata(String),

    /// Underlying filesystem I/O failure during context construction.
    #[error("IO error: {0}")]
    Io(String),

    /// Source-file parse failure (syn / tree-sitter level).
    #[error("Parse error: {0}")]
    Parse(String),

    /// SymbolPath or import resolution failure during context wiring.
    #[error("Resolve error: {0}")]
    Resolve(String),

    /// Failure while regenerating Rust source from a mutated AST; wraps the
    /// underlying [`ryo_source::pure::ToSynError`].
    #[error("Source generation error: {0}")]
    SourceGen(#[from] ryo_source::pure::ToSynError),
}

/// Unified context containing all analysis structures.
///
/// This is the recommended way to initialize code analysis from source files.
/// Executor receives this context and works with SymbolId-based Intent.
///
/// # Fork-on-Write Pattern
///
/// AnalysisContext supports fork-on-write for speculative execution:
///
/// ```ignore
/// let forked = ctx.fork();  // O(log n) structural sharing
/// // Mutations on forked don't affect original
/// ```
///
/// Uses `im::HashMap<FileId, Arc<PureFile>>` for efficient cloning:
/// - Clone is O(log n) via structural sharing
/// - Modifications only copy affected nodes
/// - Arc ensures PureFile is shared until modified
///
/// See `docs/parallel-execution-design.md` for design details.
pub struct AnalysisContext {
    /// Workspace root path (shared via Arc for efficient cloning).
    pub workspace_root: Arc<Path>,
    /// Symbol registry for path ↔ SymbolId mapping.
    pub registry: SymbolRegistry,
    /// Code graph for symbol relationships.
    pub code_graph: CodeGraphV2,
    /// Type flow graph for type relationships.
    pub typeflow_graph: TypeFlowGraphV2,
    /// Data flow graph for variable-level flow analysis.
    pub dataflow_graph: DataFlowGraphV2,
    /// Cached symbol details for O(1) access.
    pub detail_store: DetailStore,
    /// Complete AST storage for v2 mutation engine.
    ///
    /// Stores full PureItem per symbol, replacing file-based mutation approach.
    /// Used by ASTMutationEngine for registry-only execution.
    pub ast_registry: ASTRegistry,
    /// Source files with structural sharing for O(log n) fork.
    /// Key: WorkspaceFilePath (self-contained, no external registry needed)
    pub files: ImHashMap<WorkspaceFilePath, Arc<PureFile>>,
    /// Original source strings for diff generation.
    pub original: HashMap<WorkspaceFilePath, String>,
    /// Use statement resolver for cross-crate symbol resolution.
    pub use_resolver: UseResolver,
    /// Literal search index (feature-gated).
    #[cfg(feature = "literal-search")]
    pub literal_index: Option<crate::literal::LiteralIndex>,
    /// Derive index for fast derive trait validation (O(1) lookup).
    pub derive_index: crate::query::DeriveIndex,
}

/// Configuration for context building.
#[derive(Debug, Clone, Default)]
pub struct AnalysisConfig {
    /// Build with parallel processing.
    pub parallel: bool,
    /// Only include public items (default: false = include all).
    pub pub_only: bool,
    /// Preloaded UUID mappings from previous session.
    /// SymbolPath (string) → UUID (string) for JSON compatibility.
    pub uuid_mappings: Option<HashMap<String, String>>,
}

impl AnalysisConfig {
    /// Construct a default configuration (sequential build, all symbols
    /// included, no preloaded UUID mappings).
    pub fn new() -> Self {
        Self::default()
    }

    /// Enable parallel processing during context build (builder-style).
    pub fn parallel(mut self) -> Self {
        self.parallel = true;
        self
    }

    /// Only include public items, excluding private symbols.
    pub fn pub_only(mut self) -> Self {
        self.pub_only = true;
        self
    }

    /// Set preloaded UUID mappings from previous session.
    pub fn with_uuid_mappings(mut self, mappings: HashMap<String, String>) -> Self {
        self.uuid_mappings = Some(mappings);
        self
    }
}

impl AnalysisContext {
    // ========================================================================
    // Public API - Primary Entry Point
    // ========================================================================

    /// Create context from workspace root path.
    ///
    /// **This is the recommended API for workspace-aware analysis.**
    ///
    /// Automatically discovers and loads all Rust files in the workspace,
    /// using CargoMetadataProvider for accurate crate name resolution.
    /// Also loads UUID mappings from `.ryo/uuid-mapping.json` if present.
    ///
    /// # Example
    /// ```ignore
    /// use ryo_analysis::AnalysisContext;
    ///
    /// let ctx = AnalysisContext::from_workspace_root("/path/to/project")?;
    /// let symbol = ctx.registry.lookup(&path);
    /// ```
    pub fn from_workspace_root(path: impl AsRef<Path>) -> Result<Self, ContextError> {
        use ryo_symbol::{CargoMetadataProvider, WorkspaceMetadataProvider};

        let path = path.as_ref();

        // 1. Create CargoMetadataProvider for workspace info
        let metadata = CargoMetadataProvider::from_directory(path)
            .map_err(|e| ContextError::Metadata(e.to_string()))?;

        let workspace_root = metadata.workspace_root().to_path_buf();
        let resolver = WorkspacePathResolver::new(workspace_root.clone());

        // 2. Load UUID mappings from previous session
        let uuid_mappings = Self::load_uuid_mappings(&workspace_root);

        // 3. Load all Rust files from workspace
        let mut files = HashMap::new();
        Self::load_dir(
            &workspace_root,
            &workspace_root,
            &resolver,
            &metadata,
            &mut files,
        )?;

        // 4. Build context with UUID mappings
        let config = match uuid_mappings {
            Some(mappings) => AnalysisConfig::default().with_uuid_mappings(mappings),
            None => AnalysisConfig::default(),
        };

        Self::build_from_workspace_files(files, Arc::from(workspace_root.as_path()), config)
    }

    /// Create context from workspace root with parallel processing.
    pub fn from_workspace_root_parallel(path: impl AsRef<Path>) -> Result<Self, ContextError> {
        use ryo_symbol::{CargoMetadataProvider, WorkspaceMetadataProvider};

        let path = path.as_ref();

        let metadata = CargoMetadataProvider::from_directory(path)
            .map_err(|e| ContextError::Metadata(e.to_string()))?;

        let workspace_root = metadata.workspace_root().to_path_buf();
        let resolver = WorkspacePathResolver::new(workspace_root.clone());

        // Load UUID mappings from previous session
        let uuid_mappings = Self::load_uuid_mappings(&workspace_root);

        let mut files = HashMap::new();
        Self::load_dir(
            &workspace_root,
            &workspace_root,
            &resolver,
            &metadata,
            &mut files,
        )?;

        // Build context with UUID mappings
        let config = match uuid_mappings {
            Some(mappings) => AnalysisConfig::new()
                .parallel()
                .with_uuid_mappings(mappings),
            None => AnalysisConfig::new().parallel(),
        };

        Self::build_from_workspace_files(files, Arc::from(workspace_root.as_path()), config)
    }

    /// Load UUID mappings from `.ryo/uuid-mapping.json`.
    /// Returns None if file doesn't exist or is invalid.
    fn load_uuid_mappings(workspace_root: &std::path::Path) -> Option<HashMap<String, String>> {
        let path = workspace_root.join(".ryo").join("uuid-mapping.json");
        let content = std::fs::read_to_string(&path).ok()?;
        serde_json::from_str(&content).ok()
    }

    /// Save UUID mappings to `.ryo/uuid-mapping.json`.
    ///
    /// # Deprecated
    ///
    /// **Use `UuidPersistence` trait instead.** This method performs direct file I/O
    /// which is not testable and bypasses the storage abstraction layer.
    ///
    /// Production code should use:
    /// - `Api::save_uuid_mappings()` (which uses `FileUuidStorage` internally)
    /// - `ContextLoad::take_and_save()` (for CLI standalone mode)
    ///
    /// This method is preserved for internal tests only.
    #[doc(hidden)]
    #[cfg(any(test, feature = "testing"))]
    pub fn save_uuid_mappings(&self) -> Result<(), ContextError> {
        let ryo_dir = self.workspace_root.join(".ryo");
        std::fs::create_dir_all(&ryo_dir)
            .map_err(|e| ContextError::Io(format!("Failed to create .ryo directory: {}", e)))?;

        let path = ryo_dir.join("uuid-mapping.json");
        let mappings = self.registry.export_uuid_mapping_strings();

        let content = serde_json::to_string_pretty(&mappings)
            .map_err(|e| ContextError::Io(format!("Failed to serialize UUID mappings: {}", e)))?;

        std::fs::write(&path, content)
            .map_err(|e| ContextError::Io(format!("Failed to write UUID mappings: {}", e)))?;

        Ok(())
    }

    /// Load Rust files recursively from a directory.
    fn load_dir(
        _root: &Path,
        dir: &Path,
        resolver: &WorkspacePathResolver,
        metadata: &CargoMetadataProvider,
        files: &mut HashMap<WorkspaceFilePath, PureFile>,
    ) -> Result<(), ContextError> {
        if !dir.is_dir() {
            return Ok(());
        }

        // Skip common non-source directories
        let dir_name = dir.file_name().and_then(|n| n.to_str()).unwrap_or("");
        if matches!(
            dir_name,
            "target" | "node_modules" | ".git" | "dist" | "build"
        ) {
            return Ok(());
        }

        for entry in std::fs::read_dir(dir).map_err(|e| ContextError::Io(e.to_string()))? {
            let entry = entry.map_err(|e| ContextError::Io(e.to_string()))?;
            let path = entry.path();

            if path.is_dir() {
                Self::load_dir(_root, &path, resolver, metadata, files)?;
            } else if path.extension().map(|e| e == "rs").unwrap_or(false) {
                match Self::load_file(&path, resolver, metadata) {
                    Ok((wfp, file)) => {
                        files.insert(wfp, file);
                    }
                    Err(_e) => {
                        // Skip unparseable files silently (common for macro-generated code)
                    }
                }
            }
        }

        Ok(())
    }

    /// Load and parse a single Rust file.
    fn load_file(
        path: &Path,
        resolver: &WorkspacePathResolver,
        metadata: &CargoMetadataProvider,
    ) -> Result<(WorkspaceFilePath, PureFile), ContextError> {
        let content = std::fs::read_to_string(path)
            .map_err(|e| ContextError::Io(format!("{}: {}", path.display(), e)))?;

        let file = PureFile::from_source(&content)
            .map_err(|e| ContextError::Parse(format!("{}: {}", path.display(), e)))?;

        let wfp = resolver
            .resolve_with_provider(path, metadata)
            .map_err(|e| ContextError::Resolve(format!("{}: {}", path.display(), e)))?;

        Ok((wfp, file))
    }

    // ========================================================================
    // Test-only API (for unit/integration tests with explicit WFP injection)
    // ========================================================================

    /// Create context from WorkspaceFilePath-keyed files with full analysis.
    ///
    /// **This is a test-only API.** For production code, use `from_workspace_root`.
    ///
    /// This API allows tests to inject pre-constructed `WorkspaceFilePath` instances
    /// without filesystem access, enabling deterministic unit testing.
    ///
    /// Unlike `from_im_files`, this performs full symbol analysis to populate
    /// the SymbolRegistry and CodeGraphV2. Use this for tests that need
    /// symbol-based features like pre-checks or impact analysis.
    ///
    /// Note: This includes private items by default, which is typically what tests need.
    ///
    /// # Panics
    /// Panics if files is empty.
    #[doc(hidden)]
    pub fn from_workspace_files(files: HashMap<WorkspaceFilePath, PureFile>) -> Self {
        let workspace_root = files
            .keys()
            .next()
            .expect("from_workspace_files requires at least one file")
            .workspace_root()
            .into();

        // Default: include all symbols (pub_only: false)
        Self::build_from_workspace_files(files, workspace_root, AnalysisConfig::default())
            .expect("build_from_workspace_files failed in test API")
    }

    // ========================================================================
    // Internal / Speculative Execution Support
    // ========================================================================

    /// Create a minimal context from WorkspaceFilePath-keyed files.
    ///
    /// This is useful for speculative execution where you want to work with
    /// a snapshot of files without full re-analysis.
    ///
    /// Note: This creates a partial context with empty symbol registry and code graph.
    /// Suitable for mutation execution but not for symbol-based queries.
    ///
    /// # Panics
    /// Panics if files is empty (cannot infer workspace_root).
    pub fn from_im_files(files: ImHashMap<WorkspaceFilePath, Arc<PureFile>>) -> Self {
        // Extract workspace_root from the first file's WorkspaceFilePath
        let workspace_root = files
            .keys()
            .next()
            .expect("from_im_files requires at least one file")
            .workspace_root()
            .into();

        Self {
            workspace_root,
            files,
            original: HashMap::new(),
            registry: SymbolRegistry::new(),
            code_graph: CodeGraphV2::new(),
            typeflow_graph: TypeFlowGraphV2::new(),
            dataflow_graph: DataFlowGraphV2::new(),
            detail_store: DetailStore::default(),
            ast_registry: ASTRegistry::new(),
            use_resolver: UseResolver::new(),
            #[cfg(feature = "literal-search")]
            literal_index: None,
            derive_index: crate::query::DeriveIndex::new(),
        }
    }

    // ========================================================================
    // Internal Build Implementation
    // ========================================================================

    /// Build context from WorkspaceFilePath-keyed files (internal implementation).
    ///
    /// # Panics
    /// Panics if `files` is empty (no crate_name can be inferred). All public
    /// callers (`from_workspace_files`, `from_im_files`, `fork_rebuild`)
    /// document the same precondition.
    fn build_from_workspace_files(
        files: HashMap<WorkspaceFilePath, PureFile>,
        workspace_root: Arc<Path>,
        config: AnalysisConfig,
    ) -> Result<Self, ContextError> {
        let mut registry = SymbolRegistry::new();

        // Preload UUID mappings from previous session before registering symbols
        if let Some(mappings) = config.uuid_mappings {
            registry.preload_uuid_mapping_strings(mappings);
        }

        let mut code_graph = CodeGraphV2::new();

        // Resolve crate_name from first file's WorkspaceFilePath
        let crate_name = files
            .keys()
            .next()
            .expect("No files loaded - cannot determine crate name")
            .crate_name()
            .as_str()
            .to_string();

        // Extract original source before analysis
        let original: HashMap<WorkspaceFilePath, String> = files
            .iter()
            .map(|(path, file)| Ok((path.clone(), file.to_source()?)))
            .collect::<Result<HashMap<_, _>, ContextError>>()?;

        // Phase 1: Collect all symbols
        let symbols = if config.parallel {
            Self::collect_symbols_workspace_parallel(&files, &crate_name, config.pub_only)
        } else {
            Self::collect_symbols_workspace(&files, &crate_name, config.pub_only)
        };

        // Phase 2: Register symbols and build graph
        let mut symbol_ids: HashMap<String, SymbolId> = HashMap::new();

        for (path, kind, pure_vis, file_path) in symbols {
            let path_str = path.to_string();
            if let Ok(id) = registry.register(path, kind) {
                code_graph.add_node(id);
                code_graph.add_to_kind_index(id, kind);
                symbol_ids.insert(path_str, id);
                // Set visibility
                let vis = pure_vis_to_visibility(&pure_vis);
                let _ = registry.set_visibility(id, vis);
                // Set span info for correct file path resolution
                // This enables FileDumper to write to the correct file (main.rs vs lib.rs)
                let span = FileSpan::new(file_path, 0, 0);
                let _ = registry.set_span(id, span);
            }
        }

        // Phase 3: Build edges (Contains relationships)
        Self::build_contains_edges_workspace(&files, &crate_name, &symbol_ids, &mut code_graph);

        // Phase 4: Build UseResolver for cross-crate symbol resolution
        // (Must be before Phase 5 to enable use-aware type resolution)
        let mut use_resolver = UseResolver::new();
        for (file_path, file) in &files {
            // Use the crate_name from each file's WorkspaceFilePath for correct multi-crate workspace support
            let file_crate_name = file_path.crate_name().as_str();
            if let Ok(crate_name_obj) = ryo_symbol::CrateName::new(file_crate_name) {
                let path_resolver = SymbolPathResolver::new(file_crate_name);
                let mod_path_str = path_resolver.module_path_str(file_path);
                if let Ok(module_path) = SymbolPath::parse(&mod_path_str) {
                    let import_map = build_import_map(file, &crate_name_obj, &module_path);
                    use_resolver.register(module_path, import_map);
                }
            }
        }

        // Phase 4.5: Register public re-exports in SymbolRegistry
        // This populates alias_to_canonical so that registry.lookup() can resolve
        // re-export paths (e.g., tokio::sync::Mutex → tokio::sync::mutex::Mutex).
        for (file_path, file) in &files {
            let file_crate_name = file_path.crate_name().as_str();
            if let Ok(crate_name_obj) = ryo_symbol::CrateName::new(file_crate_name) {
                let path_resolver = SymbolPathResolver::new(file_crate_name);
                let mod_path_str = path_resolver.module_path_str(file_path);
                if let Ok(module_path) = SymbolPath::parse(&mod_path_str) {
                    let reexports = collect_public_reexports(file, &crate_name_obj, &module_path);
                    for entry in reexports {
                        if let Ok(alias_path) = module_path.child(&entry.local_name) {
                            // Only register if canonical symbol exists and alias differs
                            if let Some(canonical_id) = registry.lookup(&entry.full_path) {
                                if registry.lookup(&alias_path).is_none() {
                                    let _ = registry.register_reexport(
                                        canonical_id,
                                        alias_path,
                                        file_path.clone(),
                                    );
                                }
                            }
                        }
                    }
                }
            }
        }

        // Phase 5: Build call/use edges (uses UseResolver for import resolution)
        Self::build_reference_edges_workspace(
            &files,
            &crate_name,
            &symbol_ids,
            &use_resolver,
            &registry,
            &mut code_graph,
        );

        // Note: CodeGraphV2 builds indices incrementally (no rebuild needed)

        // Phase 6: Build detail store
        // Note: Using deprecated file-based method for initial construction
        // (ASTRegistry not yet available at this point)
        #[allow(deprecated)]
        let detail_store = DetailStore::build_all_workspace(&registry, &files, &crate_name);

        // Convert to im::HashMap with Arc for structural sharing
        let im_files: ImHashMap<WorkspaceFilePath, Arc<PureFile>> = files
            .into_iter()
            .map(|(path, file)| (path, Arc::new(file)))
            .collect();

        // Phase 7: Build TypeFlowGraph
        // Note: Using deprecated file-based method for initial construction
        #[allow(deprecated)]
        let typeflow_graph =
            TypeFlowBuilderV2::new_workspace(&registry, &im_files, &crate_name).build();

        // Phase 8: Build DataFlowGraph
        let dataflow_graph =
            DataFlowBuilderWorkspace::new(&registry, &im_files, &crate_name).build();

        // Phase 9: Build ASTRegistry (complete PureItem per symbol)
        let ast_registry = ASTRegistry::build_from_files(&im_files, &registry, &crate_name);

        // Phase 11: Build LiteralIndex (feature-gated)
        #[cfg(feature = "literal-search")]
        let literal_index =
            crate::literal::LiteralIndex::build_from_workspace_files(&im_files, &registry).ok();

        // Phase 12: Build DeriveIndex for fast derive validation
        let derive_index = crate::query::DeriveIndex::build(
            &ast_registry,
            &code_graph,
            &typeflow_graph,
            &registry,
        );

        Ok(Self {
            workspace_root,
            registry,
            code_graph,
            typeflow_graph,
            dataflow_graph,
            detail_store,
            ast_registry,
            files: im_files,
            original,
            use_resolver,
            #[cfg(feature = "literal-search")]
            literal_index,
            derive_index,
        })
    }

    /// Collect symbols from WorkspaceFilePath-keyed files sequentially.
    fn collect_symbols_workspace(
        files: &HashMap<WorkspaceFilePath, PureFile>,
        _crate_name: &str,
        pub_only: bool,
    ) -> Vec<(SymbolPath, SymbolKind, PureVis, WorkspaceFilePath)> {
        let mut symbols = Vec::new();

        for (file_path, file) in files {
            // Use the crate_name from each file's WorkspaceFilePath for correct multi-crate workspace support
            let file_crate_name = file_path.crate_name().as_str();
            let resolver = SymbolPathResolver::new(file_crate_name);
            let mod_path = resolver.module_path_str(file_path);
            let mut file_symbols = Vec::new();
            Self::collect_from_file(&mod_path, file, pub_only, &mut file_symbols);
            for (path, kind, vis) in file_symbols {
                symbols.push((path, kind, vis, file_path.clone()));
            }
        }

        symbols
    }

    /// Collect symbols from WorkspaceFilePath-keyed files in parallel.
    fn collect_symbols_workspace_parallel(
        files: &HashMap<WorkspaceFilePath, PureFile>,
        _crate_name: &str,
        pub_only: bool,
    ) -> Vec<(SymbolPath, SymbolKind, PureVis, WorkspaceFilePath)> {
        files
            .par_iter()
            .flat_map(|(file_path, file)| {
                // Use the crate_name from each file's WorkspaceFilePath for correct multi-crate workspace support
                let file_crate_name = file_path.crate_name().as_str();
                let resolver = SymbolPathResolver::new(file_crate_name);
                let mod_path = resolver.module_path_str(file_path);
                let mut symbols = Vec::new();
                Self::collect_from_file(&mod_path, file, pub_only, &mut symbols);
                symbols
                    .into_iter()
                    .map(|(path, kind, vis)| (path, kind, vis, file_path.clone()))
                    .collect::<Vec<_>>()
            })
            .collect()
    }

    /// Collect symbols from a single file.
    fn collect_from_file(
        mod_path: &str,
        file: &PureFile,
        pub_only: bool,
        out: &mut Vec<(SymbolPath, SymbolKind, PureVis)>,
    ) {
        // Add module itself (modules are public by default in the context of collection)
        if let Ok(path) = SymbolPath::parse(mod_path) {
            out.push((path, SymbolKind::Mod, PureVis::Public));
        }

        // Collect items
        for item in &file.items {
            Self::collect_from_item(mod_path, item, pub_only, out);
        }
    }

    /// Collect symbols from an item.
    fn collect_from_item(
        parent_path: &str,
        item: &PureItem,
        pub_only: bool,
        out: &mut Vec<(SymbolPath, SymbolKind, PureVis)>,
    ) {
        let (name, kind, vis) = match item {
            PureItem::Struct(s) => {
                if pub_only && s.vis == PureVis::Private {
                    return;
                }
                if let Ok(parent) = SymbolPath::parse(parent_path) {
                    if let Ok(struct_path) = parent.child(&s.name) {
                        out.push((struct_path.clone(), SymbolKind::Struct, s.vis.clone()));
                        // Collect named fields
                        if let PureFields::Named(fields) = &s.fields {
                            for field in fields {
                                if let Ok(field_path) = struct_path.child(&field.name) {
                                    out.push((field_path, SymbolKind::Field, field.vis.clone()));
                                }
                            }
                        }
                    }
                }
                return;
            }
            PureItem::Enum(e) => {
                // Skip private enums if pub_only mode
                if pub_only && e.vis == PureVis::Private {
                    return;
                }
                let enum_path = format!("{}::{}", parent_path, e.name);
                if let Ok(path) = SymbolPath::parse(&enum_path) {
                    out.push((path, SymbolKind::Enum, e.vis.clone()));
                }
                // Collect enum variants
                for variant in &e.variants {
                    let variant_path = format!("{}::{}", enum_path, variant.name);
                    if let Ok(path) = SymbolPath::parse(&variant_path) {
                        // Variants inherit enum's visibility
                        out.push((path, SymbolKind::Variant, e.vis.clone()));
                    }
                }
                return;
            }
            PureItem::Fn(f) => (f.name.clone(), SymbolKind::Function, f.vis.clone()),
            PureItem::Trait(t) => {
                if pub_only && t.vis == PureVis::Private {
                    return;
                }
                if let Ok(parent) = SymbolPath::parse(parent_path) {
                    if let Ok(trait_path) = parent.child(&t.name) {
                        out.push((trait_path.clone(), SymbolKind::Trait, t.vis.clone()));
                        // Collect trait items (methods, consts, associated types)
                        for trait_item in &t.items {
                            let (item_name, item_kind) = match trait_item {
                                PureTraitItem::Fn(f) => (&f.name, SymbolKind::Method),
                                PureTraitItem::Const(c) => (&c.name, SymbolKind::Const),
                                PureTraitItem::Type { name, .. } => (name, SymbolKind::TypeAlias),
                                PureTraitItem::Other(_) => continue,
                            };
                            if let Ok(item_path) = trait_path.child(item_name) {
                                // Trait items inherit trait's visibility
                                out.push((item_path, item_kind, t.vis.clone()));
                            }
                        }
                    }
                }
                return;
            }
            PureItem::Impl(i) => {
                Self::collect_from_impl(parent_path, i, pub_only, out);
                return;
            }
            PureItem::Mod(m) => {
                if pub_only && m.vis == PureVis::Private {
                    return;
                }
                let mod_path = format!("{}::{}", parent_path, m.name);
                if let Ok(path) = SymbolPath::parse(&mod_path) {
                    out.push((path, SymbolKind::Mod, m.vis.clone()));
                }
                // Recursively collect from inline module
                for inner_item in &m.items {
                    Self::collect_from_item(&mod_path, inner_item, pub_only, out);
                }
                return;
            }
            PureItem::Use(_) => return,
            PureItem::Const(c) => (c.name.clone(), SymbolKind::Const, c.vis.clone()),
            PureItem::Static(s) => (s.name.clone(), SymbolKind::Static, s.vis.clone()),
            PureItem::Type(t) => (t.name.clone(), SymbolKind::TypeAlias, t.vis.clone()),
            PureItem::Macro(_) => return,
            PureItem::Other(_) => return,
        };

        // Skip private items if pub_only mode
        if pub_only && vis == PureVis::Private {
            return;
        }

        let full_path = format!("{}::{}", parent_path, name);
        if let Ok(path) = SymbolPath::parse(&full_path) {
            out.push((path, kind, vis));
        }
    }

    /// Collect symbols from an impl block.
    ///
    /// Core design:
    /// - Impl blocks are registered as symbols (for trait operations)
    /// - Methods are registered directly on parent type (plain impl) or trait path (trait impl)
    /// - Impl block path: <impl Type> or <impl Trait for Type>
    /// - Method path: Type::method or <impl Trait for Type>::method
    fn collect_from_impl(
        parent_path: &str,
        impl_block: &PureImpl,
        pub_only: bool,
        out: &mut Vec<(SymbolPath, SymbolKind, PureVis)>,
    ) {
        let parent = match SymbolPath::parse(parent_path) {
            Ok(p) => p,
            Err(_) => return,
        };
        let impl_target = &impl_block.self_ty;

        // Register impl block and determine method base path
        // - Trait impl: methods under <impl Trait for Type>::method
        // - Plain impl: impl block registered as <impl Type>, methods under Type::method
        let method_base = if let Some(ref trait_name) = impl_block.trait_ {
            let impl_path = parent.child_trait_impl(trait_name, impl_target);
            out.push((impl_path.clone(), SymbolKind::Impl, PureVis::Public));
            impl_path
        } else {
            let impl_path = parent.child_inherent_impl(impl_target);
            out.push((impl_path, SymbolKind::Impl, PureVis::Public));
            // Strip generic parameters: "Router < S >" → "Router"
            // validate_rust_identifier rejects names with '<' / spaces,
            // so we must use the base type name for the method path.
            let base_type = impl_target.split('<').next().unwrap_or(impl_target).trim();
            match parent.child(base_type) {
                Ok(p) => p,
                Err(_) => return,
            }
        };

        // Register methods and associated items under the method base path
        for item in &impl_block.items {
            let (name, kind, vis) = match item {
                PureImplItem::Fn(m) => (m.name.clone(), SymbolKind::Method, m.vis.clone()),
                PureImplItem::Const(c) => (c.name.clone(), SymbolKind::Const, c.vis.clone()),
                PureImplItem::Type(t) => (t.name.clone(), SymbolKind::TypeAlias, t.vis.clone()),
                PureImplItem::Other(_) => continue,
            };

            if pub_only && vis == PureVis::Private {
                continue;
            }

            if let Ok(path) = method_base.child(&name) {
                out.push((path, kind, vis));
            }
        }
    }

    /// Build Contains edges (parent → child).
    ///
    /// Note: This function is file-agnostic as it only uses symbol_ids.
    fn build_contains_edges_workspace(
        _files: &HashMap<WorkspaceFilePath, PureFile>,
        _crate_name: &str,
        symbol_ids: &HashMap<String, SymbolId>,
        graph: &mut CodeGraphV2,
    ) {
        // Build parent-child relationships based on path hierarchy
        for (path_str, &child_id) in symbol_ids {
            if let Some(parent_path) = get_parent_path(path_str) {
                if let Some(&parent_id) = symbol_ids.get(&parent_path) {
                    graph.add_edge(parent_id, child_id, CodeEdgeV2::Contains);
                }
            }
        }
    }

    /// Build reference edges from WorkspaceFilePath-keyed files.
    fn build_reference_edges_workspace(
        files: &HashMap<WorkspaceFilePath, PureFile>,
        _crate_name: &str,
        symbol_ids: &HashMap<String, SymbolId>,
        use_resolver: &UseResolver,
        registry: &SymbolRegistry,
        graph: &mut CodeGraphV2,
    ) {
        let method_index = build_method_name_index(symbol_ids, registry);
        for (file_path, file) in files {
            // Use the crate_name from each file's WorkspaceFilePath for correct multi-crate workspace support
            let file_crate_name = file_path.crate_name().as_str();
            let resolver = SymbolPathResolver::new(file_crate_name);
            let mod_path = resolver.module_path_str(file_path);
            Self::build_edges_from_items(
                &mod_path,
                &file.items,
                symbol_ids,
                use_resolver,
                registry,
                graph,
                &method_index,
            );
        }
    }

    /// Build edges from a list of items.
    fn build_edges_from_items(
        parent_path: &str,
        items: &[PureItem],
        symbol_ids: &HashMap<String, SymbolId>,
        use_resolver: &UseResolver,
        registry: &SymbolRegistry,
        graph: &mut CodeGraphV2,
        method_index: &MethodNameIndex,
    ) {
        for item in items {
            match item {
                PureItem::Impl(impl_block) => {
                    Self::build_edges_from_impl(
                        parent_path,
                        impl_block,
                        symbol_ids,
                        use_resolver,
                        registry,
                        graph,
                        method_index,
                    );
                }
                PureItem::Fn(func) => {
                    let fn_path = format!("{}::{}", parent_path, func.name);
                    Self::build_edges_from_fn(
                        &fn_path,
                        func,
                        symbol_ids,
                        use_resolver,
                        registry,
                        graph,
                        method_index,
                    );
                }
                PureItem::Struct(_) => {
                    // Struct field type edges handled by TypeFlowGraphV2
                }
                PureItem::Mod(m) if !m.items.is_empty() => {
                    let mod_path = format!("{}::{}", parent_path, m.name);
                    Self::build_edges_from_items(
                        &mod_path,
                        &m.items,
                        symbol_ids,
                        use_resolver,
                        registry,
                        graph,
                        method_index,
                    );
                }
                _ => {}
            }
        }
    }

    /// Build edges from a single PureItem (for symbol-based incremental updates).
    ///
    /// This is the core method for Phase 2 symbol-based updates, allowing
    /// edge rebuilding directly from ASTRegistry without file I/O.
    fn build_edges_from_item(
        parent_path: &str,
        item: &PureItem,
        symbol_ids: &HashMap<String, SymbolId>,
        use_resolver: &UseResolver,
        registry: &SymbolRegistry,
        graph: &mut CodeGraphV2,
        method_index: &MethodNameIndex,
    ) {
        match item {
            PureItem::Impl(impl_block) => {
                Self::build_edges_from_impl(
                    parent_path,
                    impl_block,
                    symbol_ids,
                    use_resolver,
                    registry,
                    graph,
                    method_index,
                );
            }
            PureItem::Fn(func) => {
                let fn_path = format!("{}::{}", parent_path, func.name);
                Self::build_edges_from_fn(
                    &fn_path,
                    func,
                    symbol_ids,
                    use_resolver,
                    registry,
                    graph,
                    method_index,
                );
            }
            PureItem::Struct(_) => {
                // Struct field type edges handled by TypeFlowGraphV2
            }
            PureItem::Mod(m) if !m.items.is_empty() => {
                let mod_path = format!("{}::{}", parent_path, m.name);
                Self::build_edges_from_items(
                    &mod_path,
                    &m.items,
                    symbol_ids,
                    use_resolver,
                    registry,
                    graph,
                    method_index,
                );
            }
            _ => {}
        }
    }

    /// Build edges from an impl block.
    fn build_edges_from_impl(
        parent_path: &str,
        impl_block: &PureImpl,
        symbol_ids: &HashMap<String, SymbolId>,
        use_resolver: &UseResolver,
        registry: &SymbolRegistry,
        graph: &mut CodeGraphV2,
        method_index: &MethodNameIndex,
    ) {
        let parent = match SymbolPath::parse(parent_path) {
            Ok(p) => p,
            Err(_) => return,
        };
        let impl_target = &impl_block.self_ty;

        // Build impl block path
        let impl_path = if let Some(ref trait_name) = &impl_block.trait_ {
            parent.child_trait_impl(trait_name, impl_target)
        } else {
            parent.child_inherent_impl(impl_target)
        };

        // Get impl block's SymbolId
        let impl_id = match symbol_ids.get(&impl_path.to_string()) {
            Some(&id) => id,
            None => return,
        };

        // Implements edge: impl block -> trait
        if let Some(ref trait_name) = &impl_block.trait_ {
            if let Some(trait_id) = Self::resolve_type_reference(
                parent_path,
                trait_name,
                symbol_ids,
                use_resolver,
                registry,
            ) {
                graph.add_edge(impl_id, trait_id, CodeEdgeV2::Implements);
            }
        }

        // Note: Uses edge (impl -> self type) handled by TypeFlowGraphV2

        // Process methods in impl block
        // - Trait impl: methods registered under <impl Trait for Type>::method
        // - Plain impl: methods registered under Type::method
        let method_base = if impl_block.trait_.is_some() {
            impl_path
        } else {
            // Strip generic parameters: "Router < S >" → "Router"
            let base_type = impl_target.split('<').next().unwrap_or(impl_target).trim();
            match parent.child(base_type) {
                Ok(p) => p,
                Err(_) => return,
            }
        };

        for item in &impl_block.items {
            if let PureImplItem::Fn(func) = item {
                if let Ok(method_path) = method_base.child(&func.name) {
                    Self::build_edges_from_fn(
                        &method_path.to_string(),
                        func,
                        symbol_ids,
                        use_resolver,
                        registry,
                        graph,
                        method_index,
                    );
                }
            }
        }
    }

    /// Build edges from a function.
    fn build_edges_from_fn(
        fn_path: &str,
        func: &PureFn,
        symbol_ids: &HashMap<String, SymbolId>,
        use_resolver: &UseResolver,
        registry: &SymbolRegistry,
        graph: &mut CodeGraphV2,
        method_index: &MethodNameIndex,
    ) {
        let fn_id = match symbol_ids.get(fn_path) {
            Some(&id) => id,
            None => return,
        };

        // Get parent path for type resolution
        let parent_path = get_parent_path(fn_path).unwrap_or_default();

        // Note: Uses edges (type references) are handled by TypeFlowGraphV2.
        // Only Calls edges remain in CodeGraphV2.

        // Calls edges from function body
        let mut cx = CallsBuildContext {
            symbol_ids,
            use_resolver,
            registry,
            graph,
            method_index,
        };
        Self::build_calls_from_block(fn_id, &parent_path, &func.body, &mut cx);
    }

    /// Build Calls edges from a block.
    fn build_calls_from_block(
        caller_id: SymbolId,
        parent_path: &str,
        block: &PureBlock,
        cx: &mut CallsBuildContext<'_>,
    ) {
        for stmt in &block.stmts {
            match stmt {
                PureStmt::Local {
                    init: Some(expr), ..
                }
                | PureStmt::Semi(expr)
                | PureStmt::Expr(expr) => {
                    Self::build_calls_from_expr(caller_id, parent_path, expr, cx);
                }
                _ => {}
            }
        }
    }

    /// Build Calls edges from an expression.
    fn build_calls_from_expr(
        caller_id: SymbolId,
        parent_path: &str,
        expr: &PureExpr,
        cx: &mut CallsBuildContext<'_>,
    ) {
        use ryo_source::pure::PureExpr;

        match expr {
            PureExpr::Call { func, args } => {
                // Try to resolve the function being called
                if let PureExpr::Path(path) = func.as_ref() {
                    if let Some(callee_id) = Self::resolve_type_reference(
                        parent_path,
                        path,
                        cx.symbol_ids,
                        cx.use_resolver,
                        cx.registry,
                    ) {
                        cx.graph.add_edge(caller_id, callee_id, CodeEdgeV2::Calls);
                    }
                }
                // Recurse into arguments
                for arg in args {
                    Self::build_calls_from_expr(caller_id, parent_path, arg, cx);
                }
                // Recurse into function expression
                Self::build_calls_from_expr(caller_id, parent_path, func, cx);
            }
            PureExpr::MethodCall {
                receiver,
                method,
                args,
                ..
            } => {
                // Heuristic method resolution without type inference:
                // 1. self.method() → look up sibling method via parent_path
                // 2. General method call → use method_index for name-based lookup
                let is_self_receiver = matches!(receiver.as_ref(), PureExpr::Path(name) if name == "self")
                    || matches!(receiver.as_ref(), PureExpr::Field { expr, .. } if matches!(expr.as_ref(), PureExpr::Path(name) if name == "self"));

                let mut resolved = false;
                if is_self_receiver {
                    // self.method() — try parent_path::method (sibling in same impl)
                    let sibling_path = format!("{}::{}", parent_path, method);
                    if let Some(&callee_id) = cx.symbol_ids.get(&sibling_path) {
                        if callee_id != caller_id {
                            cx.graph.add_edge(caller_id, callee_id, CodeEdgeV2::Calls);
                            resolved = true;
                        }
                    }
                }

                // Fallback: name-based lookup via method_index
                // Skip if already resolved via self.
                //
                // Resolution strategy:
                // 1. Try receiver type hint (e.g., Json::new().render() → type=Json)
                //    If hint available, filter candidates to matching self-type only.
                // 2. self.method() with no explicit type hint: extract self_ty from
                //    parent_path (impl block) as implicit type hint.
                // 3. No hint: for common trait methods (clone, from, etc.), only resolve
                //    when there's a single unambiguous candidate.
                // 4. No hint, non-common: add all candidates (over-approximation).
                if !resolved {
                    if let Some(candidates) = cx.method_index.get(method.as_str()) {
                        // Try explicit type hint from receiver expression first,
                        // then fall back to implicit hint from self receiver's impl self_ty
                        let explicit_hint = extract_receiver_type_hint(receiver);
                        let type_hint = explicit_hint.or_else(|| {
                            if is_self_receiver {
                                extract_self_type_from_parent_path(parent_path)
                            } else {
                                None
                            }
                        });

                        if let Some(hint) = type_hint {
                            // Type hint available: filter candidates by self-type
                            let filtered: Vec<_> = candidates
                                .iter()
                                .copied()
                                .filter(|&id| candidate_matches_type_hint(id, hint, cx.registry))
                                .collect();
                            if !filtered.is_empty() {
                                for callee_id in filtered {
                                    if callee_id != caller_id {
                                        cx.graph.add_edge(caller_id, callee_id, CodeEdgeV2::Calls);
                                    }
                                }
                            } else {
                                // Hint didn't match any candidate: fall back to all
                                let is_common = is_common_trait_method(method);
                                if !is_common || candidates.len() == 1 {
                                    for &callee_id in candidates {
                                        if callee_id != caller_id {
                                            cx.graph.add_edge(
                                                caller_id,
                                                callee_id,
                                                CodeEdgeV2::Calls,
                                            );
                                        }
                                    }
                                }
                            }
                        } else {
                            // No type hint: use existing heuristic
                            let is_common = is_common_trait_method(method);
                            if !is_common || candidates.len() == 1 {
                                for &callee_id in candidates {
                                    if callee_id != caller_id {
                                        cx.graph.add_edge(caller_id, callee_id, CodeEdgeV2::Calls);
                                    }
                                }
                            }
                        }
                    }
                }

                // Recurse into receiver and arguments
                Self::build_calls_from_expr(caller_id, parent_path, receiver, cx);
                for arg in args {
                    Self::build_calls_from_expr(caller_id, parent_path, arg, cx);
                }
            }
            PureExpr::Block { block, .. } => {
                Self::build_calls_from_block(caller_id, parent_path, block, cx);
            }
            PureExpr::If {
                cond,
                then_branch,
                else_branch,
            } => {
                Self::build_calls_from_expr(caller_id, parent_path, cond, cx);
                Self::build_calls_from_block(caller_id, parent_path, then_branch, cx);
                if let Some(else_expr) = else_branch {
                    Self::build_calls_from_expr(caller_id, parent_path, else_expr, cx);
                }
            }
            PureExpr::Match {
                expr: match_expr,
                arms,
            } => {
                Self::build_calls_from_expr(caller_id, parent_path, match_expr, cx);
                for arm in arms {
                    Self::build_calls_from_expr(caller_id, parent_path, &arm.body, cx);
                    if let Some(ref guard) = arm.guard {
                        Self::build_calls_from_expr(caller_id, parent_path, guard, cx);
                    }
                }
            }
            PureExpr::Loop { body: block, .. }
            | PureExpr::Async { body: block, .. }
            | PureExpr::Unsafe(block) => {
                Self::build_calls_from_block(caller_id, parent_path, block, cx);
            }
            PureExpr::While { cond, body, .. } => {
                Self::build_calls_from_expr(caller_id, parent_path, cond, cx);
                Self::build_calls_from_block(caller_id, parent_path, body, cx);
            }
            PureExpr::For {
                expr: iter_expr,
                body,
                ..
            } => {
                Self::build_calls_from_expr(caller_id, parent_path, iter_expr, cx);
                Self::build_calls_from_block(caller_id, parent_path, body, cx);
            }
            PureExpr::Closure { body, .. } => {
                Self::build_calls_from_expr(caller_id, parent_path, body, cx);
            }
            PureExpr::Binary { left, right, .. } => {
                Self::build_calls_from_expr(caller_id, parent_path, left, cx);
                Self::build_calls_from_expr(caller_id, parent_path, right, cx);
            }
            PureExpr::Unary { expr: inner, .. }
            | PureExpr::Field { expr: inner, .. }
            | PureExpr::Await(inner)
            | PureExpr::Try(inner)
            | PureExpr::Ref { expr: inner, .. }
            | PureExpr::Cast { expr: inner, .. } => {
                Self::build_calls_from_expr(caller_id, parent_path, inner, cx);
            }
            PureExpr::Index { expr: arr, index } => {
                Self::build_calls_from_expr(caller_id, parent_path, arr, cx);
                Self::build_calls_from_expr(caller_id, parent_path, index, cx);
            }
            PureExpr::Tuple(exprs) | PureExpr::Array(exprs) => {
                for e in exprs {
                    Self::build_calls_from_expr(caller_id, parent_path, e, cx);
                }
            }
            PureExpr::Struct { fields, .. } => {
                for (_, e) in fields {
                    Self::build_calls_from_expr(caller_id, parent_path, e, cx);
                }
            }
            PureExpr::Return(Some(inner))
            | PureExpr::Break {
                expr: Some(inner), ..
            } => {
                Self::build_calls_from_expr(caller_id, parent_path, inner, cx);
            }
            PureExpr::Range { start, end, .. } => {
                if let Some(s) = start {
                    Self::build_calls_from_expr(caller_id, parent_path, s, cx);
                }
                if let Some(e) = end {
                    Self::build_calls_from_expr(caller_id, parent_path, e, cx);
                }
            }
            PureExpr::Let { expr: inner, .. } => {
                Self::build_calls_from_expr(caller_id, parent_path, inner, cx);
            }
            PureExpr::Repeat { expr: elem, len } => {
                Self::build_calls_from_expr(caller_id, parent_path, elem, cx);
                Self::build_calls_from_expr(caller_id, parent_path, len, cx);
            }
            _ => {}
        }
    }

    /// Resolve a type/trait reference to a SymbolId.
    ///
    /// Tries multiple resolution strategies:
    /// 1. UseResolver (import resolution via use statements)
    /// 2. Qualified path as-is (e.g., "std::io::Read")
    /// 3. Simple name in current module (e.g., "Foo" -> "module::Foo")
    /// 4. Simple name in parent modules
    fn resolve_type_reference(
        parent_path: &str,
        type_name: &str,
        symbol_ids: &HashMap<String, SymbolId>,
        use_resolver: &UseResolver,
        registry: &SymbolRegistry,
    ) -> Option<SymbolId> {
        // Skip primitive types
        let primitives = [
            "i8", "i16", "i32", "i64", "i128", "isize", "u8", "u16", "u32", "u64", "u128", "usize",
            "f32", "f64", "bool", "char", "str", "Self",
        ];
        if primitives.contains(&type_name) {
            return None;
        }

        // Extract the module path by stripping impl segments and method names.
        // UseResolver stores import maps keyed by module path (e.g., "mylib::mod_a"),
        // not by impl block path (e.g., "mylib::mod_a::<impl Trait for Type>::method").
        let module_path_str = strip_to_module_path(parent_path);

        // 1. Try UseResolver for import resolution
        if let Ok(module_path) = SymbolPath::parse(&module_path_str) {
            if let Some(id) = use_resolver.resolve(&module_path, type_name, registry) {
                return Some(id);
            }
        }

        // 2. Try qualified path as-is
        if type_name.contains("::") {
            if let Some(&id) = symbol_ids.get(type_name) {
                return Some(id);
            }

            // 2b. Split at first "::" and resolve prefix via imports, then append suffix.
            // e.g., "Router::new" → resolve "Router" via imports → "mylib::types::Router" + "::new"
            if let Some(split_pos) = type_name.find("::") {
                let prefix = &type_name[..split_pos];
                let suffix = &type_name[split_pos..]; // includes "::"
                if let Ok(module_path) = SymbolPath::parse(&module_path_str) {
                    if let Some(resolved_prefix_id) =
                        use_resolver.resolve(&module_path, prefix, registry)
                    {
                        let resolved_prefix_path = registry.path(resolved_prefix_id);
                        if let Some(full_path_str) = resolved_prefix_path {
                            let combined = format!("{}{}", full_path_str, suffix);
                            if let Some(&id) = symbol_ids.get(&combined) {
                                return Some(id);
                            }
                        }
                    }
                }
            }
        }

        // 3. Try in current module
        let qualified = format!("{}::{}", parent_path, type_name);
        if let Some(&id) = symbol_ids.get(&qualified) {
            return Some(id);
        }

        // 4. Try in parent modules
        let mut current_path = parent_path.to_string();
        while let Some(parent) = get_parent_path(&current_path) {
            let qualified = format!("{}::{}", parent, type_name);
            if let Some(&id) = symbol_ids.get(&qualified) {
                return Some(id);
            }
            current_path = parent;
        }

        // 5. Try as top-level (crate root)
        symbol_ids.get(type_name).copied()
    }

    /// Get the registry.
    pub fn registry(&self) -> &SymbolRegistry {
        &self.registry
    }

    /// Get mutable registry.
    pub fn registry_mut(&mut self) -> &mut SymbolRegistry {
        &mut self.registry
    }

    /// Get the code graph.
    pub fn code_graph(&self) -> &CodeGraphV2 {
        &self.code_graph
    }

    /// Get mutable code graph.
    pub fn code_graph_mut(&mut self) -> &mut CodeGraphV2 {
        &mut self.code_graph
    }

    /// Get the TypeFlow graph.
    pub fn typeflow_graph(&self) -> &TypeFlowGraphV2 {
        &self.typeflow_graph
    }

    /// Get the workspace root path.
    pub fn workspace_root(&self) -> &Path {
        &self.workspace_root
    }

    /// Get a file by path.
    pub fn file(&self, path: &WorkspaceFilePath) -> Option<&PureFile> {
        self.files.get(path).map(|arc| arc.as_ref())
    }

    /// Get mutable file by path (copy-on-write).
    ///
    /// Uses `Arc::make_mut` for copy-on-write semantics:
    /// - If Arc is uniquely owned, returns mutable reference directly
    /// - If Arc is shared, clones the PureFile first
    pub fn file_mut(&mut self, path: &WorkspaceFilePath) -> Option<&mut PureFile> {
        self.files.get_mut(path).map(Arc::make_mut)
    }

    /// Get all files.
    pub fn files(&self) -> &ImHashMap<WorkspaceFilePath, Arc<PureFile>> {
        &self.files
    }

    /// Get mutable files map.
    pub fn files_mut(&mut self) -> &mut ImHashMap<WorkspaceFilePath, Arc<PureFile>> {
        &mut self.files
    }

    /// Get original source for a file (for diff generation).
    pub fn original(&self, path: &WorkspaceFilePath) -> Option<&String> {
        self.original.get(path)
    }

    /// Get file count.
    pub fn file_count(&self) -> usize {
        self.files.len()
    }

    /// Check if context is empty.
    pub fn is_empty(&self) -> bool {
        self.files.is_empty()
    }

    // ========================================================================
    // Detail Store Access
    // ========================================================================

    /// Get the detail store.
    pub fn detail_store(&self) -> &DetailStore {
        &self.detail_store
    }

    /// Get mutable detail store.
    pub fn detail_store_mut(&mut self) -> &mut DetailStore {
        &mut self.detail_store
    }

    // ========================================================================
    // ========================================================================
    // Tick Boundary Operations
    // ========================================================================

    /// Commit changes at Tick boundary.
    ///
    /// Applies registry updates and incrementally updates CodeGraphV2 indices.
    /// This is O(k) where k is the number of updates, not O(n) for full rebuild.
    ///
    /// # Arguments
    ///
    /// * `updates` - Registry updates collected during this Tick
    ///
    /// # Performance
    ///
    /// | Operation | Before (rebuild_indices) | After (incremental) |
    /// |-----------|--------------------------|---------------------|
    /// | 10 updates, 10k symbols | O(10k) | O(10) |
    /// | 100 updates, 10k symbols | O(10k) | O(100) |
    pub fn commit_changes(&mut self, updates: &RegistryUpdateBatch) {
        // Collect affected IDs before applying updates (for detail store)
        let affected_ids: Vec<SymbolId> =
            updates.into_iter().filter_map(|u| u.target_id()).collect();

        // 1. Apply registry updates and update graph incrementally
        for update in updates {
            // Get old kind before applying (for UpdateKind)
            let _old_kind = match update {
                RegistryUpdate::UpdateKind { id, .. } => self.registry.kind(*id),
                _ => None,
            };

            // Apply to registry
            if let Err(e) = update.clone().apply(&mut self.registry) {
                eprintln!("Warning: Failed to apply registry update: {:?}", e);
                continue;
            }

            // Update graph incrementally
            match update {
                RegistryUpdate::Add { path, kind, .. } => {
                    if let Some(id) = self.registry.lookup(path) {
                        self.code_graph.add_node(id);
                        self.code_graph.add_to_kind_index(id, *kind);
                    }
                }
                RegistryUpdate::Remove { id } => {
                    self.code_graph.remove_node(*id);
                }
                RegistryUpdate::UpdateKind { id, new_kind } => {
                    // Note: CodeGraphV2 kind index is updated by re-adding
                    // (remove_from_index not needed as add_to_kind_index is idempotent)
                    if self.code_graph.contains(*id) {
                        self.code_graph.add_to_kind_index(*id, *new_kind);
                    }
                }
                // Rename/UpdateSpan/UpdateVisibility don't affect graph structure
                RegistryUpdate::Rename { .. }
                | RegistryUpdate::UpdateSpan { .. }
                | RegistryUpdate::UpdateVisibility { .. } => {}
            }
        }

        // 2. Update detail store for affected symbols
        // Resolve crate_name dynamically from files
        let crate_name = self
            .files
            .keys()
            .next()
            .and_then(|path| SymbolPathResolver::from_workspace_path(path).ok())
            .map(|r| r.crate_name().to_string())
            .unwrap_or_else(|| "crate".to_string());
        self.detail_store.rebuild_affected_workspace(
            &affected_ids,
            &self.registry,
            &self.files,
            &crate_name,
        );
    }

    /// Rebuild edges for symbols in the specified files.
    ///
    /// This is used for incremental updates after mutation:
    /// 1. Clear outgoing edges for all symbols in the files
    /// 2. Rebuild edges from the updated AST
    ///
    /// # Performance
    ///
    /// O(k * m) where k is the number of files and m is symbols per file.
    /// Much faster than full rebuild for small changes.
    pub fn rebuild_edges_for_files(&mut self, file_paths: &[WorkspaceFilePath]) {
        // Collect symbol IDs and build symbol_ids map
        let mut symbol_ids: HashMap<String, SymbolId> = HashMap::new();
        for (id, _) in self.registry.iter() {
            if let Some(path) = self.registry.resolve(id) {
                symbol_ids.insert(path.to_string(), id);
            }
        }

        for file_path in file_paths {
            // 1. Find symbols in this file and clear their outgoing edges
            for (id, _) in self.registry.iter() {
                if let Some(span) = self.registry.span(id) {
                    if &span.file == file_path {
                        self.code_graph.clear_outgoing_edges(id);
                    }
                }
            }

            // 2. Rebuild edges from the file's AST
            if let Some(file) = self.files.get(file_path) {
                let file_crate_name = file_path.crate_name().as_str();
                let resolver = SymbolPathResolver::new(file_crate_name);
                let mod_path = resolver.module_path_str(file_path);

                let method_index = build_method_name_index(&symbol_ids, &self.registry);
                Self::build_edges_from_items(
                    &mod_path,
                    &file.items,
                    &symbol_ids,
                    &self.use_resolver,
                    &self.registry,
                    &mut self.code_graph,
                    &method_index,
                );
            }
        }
    }

    /// Rebuild code_graph edges for the given symbol IDs (Phase 2: Symbol-based).
    ///
    /// This method rebuilds edges directly from ASTRegistry without file I/O:
    /// 1. Clear outgoing edges for affected symbols
    /// 2. Get AST from ASTRegistry for each symbol
    /// 3. Rebuild edges from the AST
    ///
    /// # Performance
    ///
    /// O(S) where S is the number of affected symbols.
    /// Much faster than file-based updates for targeted changes.
    pub fn rebuild_edges_for_symbols(&mut self, affected_ids: &[SymbolId]) {
        if affected_ids.is_empty() {
            return;
        }

        // Build symbol_ids map for edge resolution
        let mut symbol_ids: HashMap<String, SymbolId> = HashMap::new();
        for (id, _) in self.registry.iter() {
            if let Some(path) = self.registry.resolve(id) {
                symbol_ids.insert(path.to_string(), id);
            }
        }

        // 1. Clear outgoing edges for affected symbols
        for &id in affected_ids {
            self.code_graph.clear_outgoing_edges(id);
        }

        // 2. Rebuild edges from ASTRegistry
        for &id in affected_ids {
            // Get parent path from symbol path
            let parent_path = match self.registry.resolve(id) {
                Some(path) => {
                    // Get the parent module path (everything before the last segment)
                    let path_str = path.to_string();
                    path_str
                        .rsplit_once("::")
                        .map(|(parent, _)| parent.to_string())
                        .unwrap_or_else(|| path_str.clone())
                }
                None => continue,
            };

            // Get AST from ASTRegistry
            if let Some(item) = self.ast_registry.get(id) {
                let method_index = build_method_name_index(&symbol_ids, &self.registry);
                Self::build_edges_from_item(
                    &parent_path,
                    item,
                    &symbol_ids,
                    &self.use_resolver,
                    &self.registry,
                    &mut self.code_graph,
                    &method_index,
                );
            }
        }
    }

    /// Get all symbols defined in the specified files.
    ///
    /// Uses `registry.span()` to determine which file each symbol belongs to.
    ///
    /// # Returns
    /// Vector of SymbolIds for symbols defined in the given files.
    pub fn get_symbols_in_files(&self, file_paths: &[WorkspaceFilePath]) -> Vec<SymbolId> {
        let file_set: std::collections::HashSet<_> = file_paths.iter().collect();
        let mut symbols = Vec::new();

        for (id, _) in self.registry.iter() {
            if let Some(span) = self.registry.span(id) {
                if file_set.contains(&span.file) {
                    symbols.push(id);
                }
            }
        }

        symbols
    }

    /// Rebuild all analysis graphs after mutation execution.
    ///
    /// Converts file paths to symbol IDs and delegates to the Symbol-based
    /// rebuild path. All graphs are rebuilt from ASTRegistry (no file I/O).
    ///
    /// Note: ast_registry and files are already updated by execute_v2.
    pub fn rebuild_after_mutation(&mut self, modified_files: &[WorkspaceFilePath]) {
        let affected_symbols = self.get_symbols_in_files(modified_files);
        self.rebuild_after_mutation_by_symbols(&affected_symbols);
    }

    /// Rebuild analysis graphs for the given affected symbol IDs.
    ///
    /// This is the Symbol-based update path (Phase 2) that rebuilds all graphs
    /// directly from ASTRegistry, avoiding file reconstruction overhead.
    ///
    /// All graphs are now built from ASTRegistry (no file I/O):
    /// 1. code_graph: Incremental edge rebuild for affected symbols
    /// 2. typeflow_graph: Full rebuild from ASTRegistry
    /// 3. dataflow_graph: Incremental rebuild for affected symbols
    /// 4. detail_store: Incremental rebuild for affected symbols
    ///
    /// # Performance
    ///
    /// - code_graph: O(S) where S is affected symbols
    /// - typeflow_graph: O(N) where N is total symbols (full rebuild, but no file I/O)
    /// - dataflow_graph: O(S) incremental
    /// - detail_store: O(S) incremental
    pub fn rebuild_after_mutation_by_symbols(&mut self, affected_ids: &[SymbolId]) {
        if affected_ids.is_empty() {
            return;
        }

        // Get crate_name for builders
        let crate_name = self
            .files
            .keys()
            .next()
            .map(|r| r.crate_name().to_string())
            .unwrap_or_else(|| "unknown".to_string());

        // Extract unique file paths for components that still need file-based update
        let mut file_set = std::collections::HashSet::new();
        for &id in affected_ids {
            if let Some(span) = self.registry.span(id) {
                file_set.insert(span.file.clone());
            }
        }
        let _modified_files: Vec<_> = file_set.into_iter().collect();

        // 1. Rebuild code_graph edges (Phase 2: pure symbol-based, no file I/O)
        self.rebuild_edges_for_symbols(affected_ids);

        // 2. Rebuild typeflow_graph (Phase 2: pure symbol-based, no file I/O)
        // Full rebuild from ASTRegistry - avoids file reconstruction overhead.
        self.typeflow_graph =
            TypeFlowBuilderV2::build_from_ast_registry(&self.registry, &self.ast_registry);

        // 3. Rebuild dataflow_graph (Phase 2: pure symbol-based, no file I/O)
        self.dataflow_graph.clear_for_symbols(affected_ids);
        DataFlowBuilderWorkspace::new(&self.registry, &self.files, &crate_name)
            .build_incremental_by_symbols(
                &mut self.dataflow_graph,
                &self.ast_registry,
                affected_ids,
            );

        // 4. Rebuild detail_store (Phase 2: pure symbol-based, no file I/O)
        self.detail_store
            .rebuild_for_symbols(affected_ids, &self.ast_registry);

        // 5. Rebuild derive_index (Phase 2: pure symbol-based, O(S) incremental)
        self.derive_index.rebuild_for_symbols(
            affected_ids,
            &self.ast_registry,
            &self.code_graph,
            &self.typeflow_graph,
            &self.registry,
        );
    }

    // ========================================================================
    // Fork Operations (for Speculative Execution)
    // ========================================================================

    /// Create an ExecutionContext for parallel Mutation execution.
    ///
    /// Registry and Graph are shared as read-only references.
    /// Files use O(log n) structural sharing via `im::HashMap`.
    ///
    /// # Design
    ///
    /// During parallel Mutation execution:
    /// - Registry: Read-only, shared across all Mutations
    /// - Graph: Read-only, shared across all Mutations
    /// - Files: O(log n) clone via structural sharing, copy-on-write
    /// - Changes to Registry are collected as `RegistryUpdate` deltas
    ///
    /// # Performance
    ///
    /// Clone is O(log n) due to `im::HashMap` structural sharing.
    /// Modifications use copy-on-write via `Arc::make_mut`.
    ///
    /// # Example
    ///
    /// ```ignore
    /// let ctx = AnalysisContext::from_path_files(files, "my_crate");
    /// let mut exec_ctx = ctx.fork();  // O(log n) clone
    ///
    /// // Modify files in exec_ctx - original is unchanged
    /// exec_ctx.file_mut(&path).unwrap().modify(...);  // Copy-on-write
    ///
    /// // Registry is read-only
    /// let symbol = exec_ctx.registry.lookup(&path);
    /// ```
    pub fn fork(&self) -> ExecutionContext<'_> {
        ExecutionContext {
            workspace_root: &self.workspace_root,
            registry: &self.registry,
            graph: &self.code_graph,
            files: self.files.clone(), // O(log n) structural sharing
        }
    }

    /// Create a new AnalysisContext with files cloned.
    ///
    /// Registry, graph, and detail store are rebuilt from the cloned files.
    /// Use this when you need a completely independent context with
    /// mutable Registry access.
    ///
    /// # Note
    ///
    /// This is more expensive than `fork()` as it rebuilds all indices.
    /// Prefer `fork()` for parallel Mutation execution.
    ///
    /// # Panics
    /// Panics if the current context has zero files (cannot infer
    /// crate_name during rebuild) or if any file fails source generation
    /// during rebuild. Either situation indicates a corrupted internal
    /// state that should not occur in normal use.
    pub fn fork_rebuild(&self) -> Self {
        // Convert im::HashMap<WorkspaceFilePath, Arc<PureFile>> back to HashMap
        let files: HashMap<WorkspaceFilePath, PureFile> = self
            .files
            .iter()
            .map(|(path, arc)| (path.clone(), (**arc).clone()))
            .collect();
        Self::build_from_workspace_files(
            files,
            self.workspace_root.clone(),
            AnalysisConfig::default(),
        )
        .expect("fork_rebuild: source generation failed")
    }

    /// Create an owned clone of AnalysisContext without rebuilding.
    ///
    /// This is much faster than `fork_rebuild()` because it clones the
    /// existing graph structures directly instead of rebuilding from files.
    ///
    /// # Performance
    ///
    /// - Files: O(log n) structural sharing via `im::HashMap`
    /// - All other fields: Direct Clone (no rebuild)
    ///
    /// Expected: < 1ms vs ~100ms for `fork_rebuild()`
    ///
    /// # Use Case
    ///
    /// Use this for precheck scenarios where you need a mutable owned
    /// context but don't need to rebuild graphs from scratch.
    pub fn fork_clone(&self) -> Self {
        Self {
            workspace_root: self.workspace_root.clone(),
            registry: self.registry.clone(),
            code_graph: self.code_graph.clone(),
            typeflow_graph: self.typeflow_graph.clone(),
            dataflow_graph: self.dataflow_graph.clone(),
            detail_store: self.detail_store.clone(),
            ast_registry: self.ast_registry.clone(),
            files: self.files.clone(), // O(log n) structural sharing
            original: self.original.clone(),
            use_resolver: self.use_resolver.clone(),
            // LiteralIndex is not cloned (Tantivy Index is complex).
            // Precheck doesn't need literal search, so None is acceptable.
            #[cfg(feature = "literal-search")]
            literal_index: None,
            derive_index: self.derive_index.clone(),
        }
    }

    /// Get the number of registered symbols.
    pub fn symbol_count(&self) -> usize {
        self.registry.len()
    }

    // ========================================================================
    // Snapshot/Rollback for Efficient Speculative Execution
    // ========================================================================

    /// Take a snapshot of specified symbols before mutation.
    ///
    /// This enables efficient speculative execution by only saving the
    /// symbols that will be modified, rather than cloning the entire context.
    ///
    /// # Usage
    /// ```ignore
    /// let snapshot = ctx.snapshot_symbols(&affected_ids);
    /// // ... apply mutation ...
    /// ctx.rollback(snapshot, &affected_ids);
    /// ```
    pub fn snapshot_symbols(&self, symbols: &[SymbolId]) -> ContextSnapshot {
        let ast_items: HashMap<SymbolId, PureItem> = symbols
            .iter()
            .filter_map(|&id| self.ast_registry.get(id).map(|item| (id, item.clone())))
            .collect();

        ContextSnapshot { ast_items }
    }

    /// Rollback to a previous snapshot.
    ///
    /// Restores AST items and rebuilds analysis graphs for affected symbols.
    /// This is more efficient than fork_clone when processing many mutations
    /// sequentially on the same context.
    pub fn rollback(&mut self, snapshot: ContextSnapshot, affected_ids: &[SymbolId]) {
        // 1. Restore AST items
        for (id, item) in snapshot.ast_items {
            self.ast_registry.set(id, item);
        }

        // 2. Rebuild analysis graphs for affected symbols
        // This restores code_graph, typeflow_graph, dataflow_graph, detail_store, derive_index
        if !affected_ids.is_empty() {
            self.rebuild_after_mutation_by_symbols(affected_ids);
        }
    }
}

/// Snapshot of context state for rollback.
///
/// Used by `AnalysisContext::snapshot_symbols()` and `rollback()` for
/// efficient speculative execution without full context cloning.
#[derive(Debug, Clone)]
pub struct ContextSnapshot {
    /// Saved AST items (only the symbols that will be modified).
    pub ast_items: HashMap<SymbolId, PureItem>,
}

// ============================================================================
// ExecutionContext - Fork for Parallel Mutation Execution
// ============================================================================

/// Context for parallel Mutation execution.
///
/// Created by `AnalysisContext::fork()`. Shares Registry and Graph as
/// read-only references, with Files using O(log n) structural sharing.
///
/// # Design
///
/// ```text
/// AnalysisContext (owner)
/// ├── workspace_root: Arc<Path>   │
/// ├── registry: SymbolRegistry  ──┤
/// ├── graph: CodeGraphV2         │  shared (read-only)
/// └── files: im::HashMap<...>    │
///                                 │
/// ExecutionContext<'a>            │
/// ├── workspace_root: &'a Path     ←┘
/// ├── registry: &'a SymbolRegistry ←┘
/// ├── graph: &'a CodeGraphV2      ←┘
/// └── files: im::HashMap<...>  (O(log n) clone, copy-on-write)
/// ```
///
/// # Performance
///
/// - Clone: O(log n) via `im::HashMap` structural sharing
/// - Modification: Copy-on-write via `Arc::make_mut`
///
/// # Collecting Changes
///
/// Mutations return `RegistryUpdate` deltas instead of modifying Registry directly.
/// These are collected and applied to AnalysisContext at Tick end.
///
/// See `docs/parallel-execution-design.md` for the full design.
pub struct ExecutionContext<'a> {
    /// Read-only reference to workspace root.
    pub workspace_root: &'a Path,

    /// Read-only reference to SymbolRegistry.
    ///
    /// Mutations should collect changes as `RegistryUpdate` instead of
    /// modifying directly.
    pub registry: &'a SymbolRegistry,

    /// Read-only reference to CodeGraphV2.
    pub graph: &'a CodeGraphV2,

    /// Files with O(log n) clone via structural sharing.
    ///
    /// Uses `im::HashMap<WorkspaceFilePath, Arc<PureFile>>` for:
    /// - O(log n) clone (structural sharing)
    /// - Copy-on-write modification via `Arc::make_mut`
    pub files: ImHashMap<WorkspaceFilePath, Arc<PureFile>>,
}

impl<'a> ExecutionContext<'a> {
    /// Get a file by path.
    pub fn file(&self, path: &WorkspaceFilePath) -> Option<&PureFile> {
        self.files.get(path).map(|arc| arc.as_ref())
    }

    /// Get a mutable file by path (copy-on-write).
    ///
    /// Uses `Arc::make_mut` for copy-on-write semantics:
    /// - If Arc is uniquely owned, returns mutable reference directly
    /// - If Arc is shared, clones the PureFile first
    pub fn file_mut(&mut self, path: &WorkspaceFilePath) -> Option<&mut PureFile> {
        self.files.get_mut(path).map(Arc::make_mut)
    }

    /// Check if a file exists.
    pub fn has_file(&self, path: &WorkspaceFilePath) -> bool {
        self.files.contains_key(path)
    }

    /// Get the number of files.
    pub fn file_count(&self) -> usize {
        self.files.len()
    }
}

/// Convert PureVis to Visibility.
fn pure_vis_to_visibility(pure_vis: &PureVis) -> Visibility {
    match pure_vis {
        PureVis::Public => Visibility::Public,
        PureVis::Crate => Visibility::Crate,
        PureVis::Super => Visibility::Super,
        PureVis::Private => Visibility::Private,
        PureVis::In(path) => {
            // Try to parse as SymbolPath, fallback to Private if invalid
            SymbolPath::parse(path)
                .map(|p| Visibility::Restricted(Box::new(p)))
                .unwrap_or(Visibility::Private)
        }
    }
}

/// Get parent path from a symbol path string.
fn get_parent_path(path: &str) -> Option<String> {
    let parts: Vec<&str> = path.rsplitn(2, "::").collect();
    if parts.len() == 2 {
        Some(parts[1].to_string())
    } else {
        None
    }
}

/// Strip impl segments and trailing names from a path to get the module path.
///
/// UseResolver stores import maps keyed by module path (e.g., "mylib::module"),
/// but during edge building, parent_path may include impl block segments:
/// - `"mylib::mod_a::<impl Trait for Type>::method"` → `"mylib::mod_a"`
/// - `"mylib::mod_a::<impl Type>::method"` → `"mylib::mod_a"`
/// - `"mylib::mod_a::function"` → `"mylib::mod_a"` (if function isn't a module)
/// - `"mylib::mod_a"` → `"mylib::mod_a"` (already a module path)
fn strip_to_module_path(path: &str) -> String {
    // Find the first impl segment and truncate before it
    if let Some(impl_pos) = path.find("::<impl ") {
        return path[..impl_pos].to_string();
    }
    path.to_string()
}

/// Check if a method name is a common std trait method that would produce too many false positives.
///
/// These methods are implemented by many types (Display::fmt, Clone::clone, etc.)
/// and name-based matching would create noise rather than signal.
fn is_common_trait_method(method: &str) -> bool {
    matches!(
        method,
        "new"
            | "default"
            | "fmt"
            | "clone"
            | "eq"
            | "ne"
            | "cmp"
            | "partial_cmp"
            | "hash"
            | "from"
            | "into"
            | "try_from"
            | "try_into"
            | "as_ref"
            | "as_mut"
            | "deref"
            | "deref_mut"
            | "drop"
            | "next"
            | "into_iter"
            | "iter"
            | "len"
            | "is_empty"
    )
}

/// Extract a type hint from a method call receiver expression.
///
/// Without full type inference, we can only extract type information
/// from certain receiver patterns:
/// - `Type::method(...)` → type hint is "Type"
/// - `Type { ... }` → type hint is "Type"
///
/// Returns the base type name (without generics) if extractable.
fn extract_receiver_type_hint(receiver: &PureExpr) -> Option<&str> {
    match receiver {
        // Type::method(...) → e.g., Json::new() → "Json"
        PureExpr::Call { func, .. } => {
            if let PureExpr::Path(path) = func.as_ref() {
                // "Json::new" → "Json", "std::collections::HashMap::new" → "HashMap"
                let segments: Vec<&str> = path.rsplitn(2, "::").collect();
                if segments.len() == 2 {
                    // Return the segment before the last `::`
                    // For "Json::new" → segments = ["new", "Json"]
                    return Some(segments[1].rsplit("::").next().unwrap_or(segments[1]));
                }
            }
            None
        }
        // StructType { ... } → "StructType"
        PureExpr::Struct { path, .. } => path.rsplit("::").next(),
        _ => None,
    }
}

/// Extract the self type name from a parent path (impl block path).
///
/// For trait impl: `mylib::<impl MyTrait for MyStruct>` → `Some("MyStruct")`
/// For inherent impl: `mylib::<impl MyStruct>` → `Some("MyStruct")`
/// For plain type: `mylib::MyStruct` → `Some("MyStruct")`
/// For non-impl: `mylib::module` → `Some("module")`
///
/// Used to provide implicit type hints for `self.method()` calls
/// when explicit type hints are unavailable.
fn extract_self_type_from_parent_path(parent_path: &str) -> Option<&str> {
    // Check if parent_path ends with an impl segment: ...::<impl ...>
    if let Some(impl_start) = parent_path.rfind("::<impl ") {
        let impl_segment = &parent_path[impl_start + 2..]; // skip "::"
                                                           // impl_segment = "<impl Trait for Type>" or "<impl Type>"
        let inner = impl_segment.strip_prefix("<impl ")?.strip_suffix('>')?;

        // Extract self_ty: after " for " if trait impl, otherwise the whole inner
        let self_ty = if let Some(pos) = inner.find(" for ") {
            &inner[pos + 5..]
        } else {
            inner
        };

        // Strip generics: "MyStruct < T >" → "MyStruct"
        let base = self_ty.split('<').next().unwrap_or(self_ty).trim();
        if !base.is_empty() {
            return Some(base);
        }
    }

    // Fallback: last segment of the path (for inherent methods under Type::method)
    parent_path.rsplit("::").next()
}

/// Check if a method candidate's impl self-type matches the given type hint.
///
/// The candidate's SymbolPath contains an impl segment like `<impl Trait for Type>`.
/// We extract the base type name and compare it against the hint.
fn candidate_matches_type_hint(
    candidate_id: SymbolId,
    type_hint: &str,
    registry: &SymbolRegistry,
) -> bool {
    if let Some(path) = registry.path(candidate_id) {
        for segment in path.segment_refs() {
            if segment.is_impl() {
                if let Some(self_ty) = segment.impl_self_ty() {
                    // Strip generics: "Json < T >" → "Json"
                    let base = self_ty.split('<').next().unwrap_or(self_ty).trim();
                    // Strip leading path: "my_crate::Json" → "Json"
                    let base_name = base.rsplit("::").next().unwrap_or(base);
                    return base_name == type_hint;
                }
            }
        }
        // Inherent method without impl segment: check parent
        // Path like "mylib::Json::method" → parent type is "Json"
        let segments: Vec<&str> = path.segments().collect();
        if segments.len() >= 2 {
            let parent_name = segments[segments.len() - 2];
            return parent_name == type_hint;
        }
    }
    false
}

/// Reverse index: method name → Vec<SymbolId>.
///
/// Used for heuristic resolution of method calls without type inference.
type MethodNameIndex = HashMap<String, Vec<SymbolId>>;

/// Shared context passed through `build_calls_from_*` recursion to avoid
/// exceeding clippy's `too_many_arguments` limit.
struct CallsBuildContext<'a> {
    symbol_ids: &'a HashMap<String, SymbolId>,
    use_resolver: &'a UseResolver,
    registry: &'a SymbolRegistry,
    graph: &'a mut CodeGraphV2,
    method_index: &'a MethodNameIndex,
}

/// Build a method name index from symbol_ids.
///
/// Extracts the last segment of each qualified path and maps it to the SymbolId.
/// Only includes symbols that are actually callable (Function or Method).
/// Modules, structs, enums, traits, etc. with the same name are excluded.
fn build_method_name_index(
    symbol_ids: &HashMap<String, SymbolId>,
    registry: &SymbolRegistry,
) -> MethodNameIndex {
    let mut index: MethodNameIndex = HashMap::new();
    for (path, &id) in symbol_ids {
        // Only include callable symbols (Function or Method)
        let kind = registry.kind(id);
        let is_callable = matches!(kind, Some(SymbolKind::Function) | Some(SymbolKind::Method));
        if !is_callable {
            continue;
        }
        if let Some(method_name) = path.rsplit("::").next() {
            index.entry(method_name.to_string()).or_default().push(id);
        }
    }
    index
}

#[cfg(test)]
mod tests {
    use super::*;
    use ryo_symbol::{TestWorkspace, WorkspaceFilePath};

    /// Build AnalysisContext from TestWorkspace
    fn build_context_from_workspace(
        workspace: &TestWorkspace,
        crate_name: &str,
    ) -> AnalysisContext {
        let files: HashMap<WorkspaceFilePath, PureFile> = workspace
            .files_in_crate(crate_name)
            .into_iter()
            .filter_map(|path| {
                let abs = path.to_absolute();
                let content = std::fs::read_to_string(&abs).ok()?;
                let file = PureFile::from_source(&content).ok()?;
                Some((path, file))
            })
            .collect();
        let workspace_root = Arc::from(workspace.workspace_root());
        AnalysisContext::build_from_workspace_files(
            files,
            workspace_root,
            AnalysisConfig::default(),
        )
        .expect("build_from_workspace_files failed in test helper")
    }

    #[test]
    fn test_get_parent_path() {
        assert_eq!(
            get_parent_path("mylib::handlers::handle"),
            Some("mylib::handlers".to_string())
        );
        assert_eq!(get_parent_path("mylib::foo"), Some("mylib".to_string()));
        assert_eq!(get_parent_path("mylib"), None);
    }

    #[test]
    fn test_empty_context() {
        // Create minimal workspace with empty lib.rs
        let workspace = TestWorkspace::builder()
            .crate_with_source("test_crate", "src/lib.rs", "")
            .build();

        let ctx = build_context_from_workspace(&workspace, "test_crate");

        // Context should have minimal content (one empty file)
        assert_eq!(ctx.file_count(), 1);
        assert!(ctx.code_graph.node_count() <= 1);
    }

    #[test]
    fn test_context_with_files() {
        let workspace = TestWorkspace::builder()
            .crate_with_source("mylib", "src/lib.rs", "pub fn foo() {}")
            .build();

        let ctx = build_context_from_workspace(&workspace, "mylib");

        assert_eq!(ctx.file_count(), 1);
        // Get file by WorkspaceFilePath
        let workspace_path = ctx.files.keys().next().expect("should have one file");
        assert!(ctx.file(workspace_path).is_some());
        assert!(ctx.original(workspace_path).is_some());

        // Symbol should be registered
        let foo_path = SymbolPath::parse("mylib::foo").unwrap();
        assert!(
            ctx.registry.lookup(&foo_path).is_some(),
            "foo should be registered"
        );
    }

    #[test]
    fn test_fork_creates_independent_files() {
        let workspace = TestWorkspace::builder()
            .crate_with_source("mylib", "src/lib.rs", "pub fn foo() {}")
            .build();

        let original = build_context_from_workspace(&workspace, "mylib");
        let workspace_path = original.files.keys().next().expect("file exists").clone();
        let mut forked = original.fork();

        // Replace the Arc with a new one containing different content
        forked.files.insert(
            workspace_path.clone(),
            Arc::new(PureFile::from_source("pub fn bar() {}").unwrap()),
        );

        // Original should be unchanged
        let original_source = original.file(&workspace_path).unwrap().to_source().unwrap();
        let forked_source = forked.file(&workspace_path).unwrap().to_source().unwrap();

        assert!(original_source.contains("foo"), "Original should have foo");
        assert!(forked_source.contains("bar"), "Forked should have bar");
        assert!(
            !original_source.contains("bar"),
            "Original should not have bar"
        );
    }

    #[test]
    fn test_fork_shares_registry() {
        let workspace = TestWorkspace::builder()
            .crate_with_source("mylib", "src/lib.rs", "pub struct Foo {}")
            .build();

        let original = build_context_from_workspace(&workspace, "mylib");
        let forked = original.fork();

        // Forked registry is a reference to the same registry
        // (pointer equality - same memory address)
        assert!(std::ptr::eq(
            &original.registry as *const _,
            forked.registry as *const _
        ));

        // Both should have the same number of symbols
        assert_eq!(original.registry.len(), forked.registry.len());
    }

    #[test]
    fn test_fork_rebuild_creates_independent_context() {
        let workspace = TestWorkspace::builder()
            .crate_with_source("mylib", "src/lib.rs", "pub fn foo() {}")
            .build();

        let original = build_context_from_workspace(&workspace, "mylib");
        let rebuilt = original.fork_rebuild();

        // Rebuilt has its own registry (different memory address)
        assert!(!std::ptr::eq(
            &original.registry as *const _,
            &rebuilt.registry as *const _
        ));

        // But same content
        assert_eq!(original.registry.len(), rebuilt.registry.len());
    }

    #[test]
    fn test_execution_context_file_access() {
        let workspace = TestWorkspace::builder()
            .crate_with_source("mylib", "src/lib.rs", "pub fn test_fn() {}")
            .build();

        let ctx = build_context_from_workspace(&workspace, "mylib");
        let workspace_path = ctx.files.keys().next().expect("file exists").clone();
        let exec_ctx = ctx.fork();

        assert!(exec_ctx.has_file(&workspace_path));
        assert_eq!(exec_ctx.file_count(), 1);

        let file = exec_ctx.file(&workspace_path).unwrap();
        assert!(file.to_source().unwrap().contains("test_fn"));
    }

    // ========================================================================
    // commit_changes incremental update tests
    // ========================================================================

    #[test]
    fn test_commit_changes_add_symbol() {
        use crate::SymbolKind;
        use crate::{FileSpan, RegistryUpdate, RegistryUpdateBatch, SymbolPath};

        // Create minimal workspace to satisfy crate_name requirement
        let workspace = TestWorkspace::builder()
            .crate_with_source("testcrate", "src/lib.rs", "")
            .build();
        let mut ctx = build_context_from_workspace(&workspace, "testcrate");

        // Create a batch with an Add update
        let mut batch = RegistryUpdateBatch::new();
        let path = SymbolPath::parse("testcrate::NewStruct").unwrap();
        let dummy_span = FileSpan::new(
            WorkspaceFilePath::new_for_test("src/test.rs", "/project", "testcrate"),
            0,
            100,
        );
        batch.push(RegistryUpdate::Add {
            path: path.clone(),
            kind: SymbolKind::Struct,
            span: dummy_span,
        });

        let initial_nodes = ctx.code_graph.node_count();
        ctx.commit_changes(&batch);

        // Verify symbol was added to registry
        let id = ctx.registry.lookup(&path);
        assert!(id.is_some(), "Symbol should be registered");

        // Verify node was added to graph
        assert_eq!(
            ctx.code_graph.node_count(),
            initial_nodes + 1,
            "Graph should have one more node"
        );
    }

    #[test]
    fn test_commit_changes_remove_symbol() {
        use crate::{RegistryUpdate, RegistryUpdateBatch, SymbolPath};

        // Create context with existing symbol
        let workspace = TestWorkspace::builder()
            .crate_with_source("mylib", "src/lib.rs", "pub struct Foo {}")
            .build();

        let mut ctx = build_context_from_workspace(&workspace, "mylib");

        // Find the Foo struct's ID
        let foo_path = SymbolPath::parse("mylib::Foo").unwrap();
        let foo_id = ctx.registry.lookup(&foo_path);
        assert!(foo_id.is_some(), "Foo should exist initially");
        let foo_id = foo_id.unwrap();

        let initial_nodes = ctx.code_graph.node_count();

        // Create a batch with a Remove update
        let mut batch = RegistryUpdateBatch::new();
        batch.push(RegistryUpdate::Remove { id: foo_id });

        ctx.commit_changes(&batch);

        // Verify symbol was removed from registry
        let foo_path_check = SymbolPath::parse("mylib::Foo").unwrap();
        assert!(
            ctx.registry.lookup(&foo_path_check).is_none(),
            "Symbol should be removed from registry"
        );

        // Verify node was removed from graph
        assert_eq!(
            ctx.code_graph.node_count(),
            initial_nodes - 1,
            "Graph should have one fewer node"
        );
    }

    #[test]
    fn test_commit_changes_update_kind() {
        use crate::SymbolKind;
        use crate::{RegistryUpdate, RegistryUpdateBatch, SymbolPath};

        // Create context with existing symbol
        let workspace = TestWorkspace::builder()
            .crate_with_source("mylib", "src/lib.rs", "pub struct Foo {}")
            .build();

        let mut ctx = build_context_from_workspace(&workspace, "mylib");

        // Find the Foo struct's ID
        let foo_path = SymbolPath::parse("mylib::Foo").unwrap();
        let foo_id = ctx.registry.lookup(&foo_path).expect("Foo should exist");

        // Verify initial kind
        assert_eq!(ctx.registry.kind(foo_id), Some(SymbolKind::Struct));

        let initial_nodes = ctx.code_graph.node_count();

        // Create a batch to change Struct -> Enum
        let mut batch = RegistryUpdateBatch::new();
        batch.push(RegistryUpdate::UpdateKind {
            id: foo_id,
            new_kind: SymbolKind::Enum,
        });

        ctx.commit_changes(&batch);

        // Verify kind was updated in registry
        assert_eq!(
            ctx.registry.kind(foo_id),
            Some(SymbolKind::Enum),
            "Kind should be updated to Enum"
        );

        // Node count should remain the same
        assert_eq!(
            ctx.code_graph.node_count(),
            initial_nodes,
            "Node count should not change"
        );
    }

    #[test]
    fn test_commit_changes_batch_multiple_updates() {
        use crate::SymbolKind;
        use crate::{FileSpan, RegistryUpdate, RegistryUpdateBatch, SymbolPath};

        // Create minimal workspace to satisfy crate_name requirement
        let workspace = TestWorkspace::builder()
            .crate_with_source("testcrate", "src/lib.rs", "")
            .build();
        let mut ctx = build_context_from_workspace(&workspace, "testcrate");

        // Create a batch with multiple Add updates
        let mut batch = RegistryUpdateBatch::new();
        for name in ["Alpha", "Beta", "Gamma"] {
            let path = SymbolPath::parse(&format!("testcrate::{}", name)).unwrap();
            let dummy_span = FileSpan::new(
                WorkspaceFilePath::new_for_test("src/test.rs", "/project", "testcrate"),
                0,
                100,
            );
            batch.push(RegistryUpdate::Add {
                path,
                kind: SymbolKind::Struct,
                span: dummy_span,
            });
        }

        let initial_nodes = ctx.code_graph.node_count();
        ctx.commit_changes(&batch);

        // All three symbols should be added
        assert_eq!(
            ctx.code_graph.node_count(),
            initial_nodes + 3,
            "Graph should have 3 more nodes"
        );

        // Verify all symbols exist
        for name in ["Alpha", "Beta", "Gamma"] {
            let path = SymbolPath::parse(&format!("testcrate::{}", name)).unwrap();
            assert!(
                ctx.registry.lookup(&path).is_some(),
                "{} should be registered",
                name
            );
        }
    }

    // ========================================================================
    // Reference edges tests (Implements, Uses, Calls)
    // ========================================================================

    #[test]
    fn test_implements_edge() {
        let workspace = TestWorkspace::builder()
            .crate_with_source(
                "mylib",
                "src/lib.rs",
                r#"
                pub trait MyTrait {
                    fn do_something(&self);
                }

                pub struct MyStruct {}

                impl MyTrait for MyStruct {
                    fn do_something(&self) {}
                }
                "#,
            )
            .build();

        let ctx = build_context_from_workspace(&workspace, "mylib");

        // Find the trait
        let trait_path = SymbolPath::parse("mylib::MyTrait").unwrap();
        let trait_id = ctx.registry.lookup(&trait_path);
        assert!(trait_id.is_some(), "Trait should be registered");

        // Find the struct
        let struct_path = SymbolPath::parse("mylib::MyStruct").unwrap();
        let struct_id = ctx.registry.lookup(&struct_path);
        assert!(struct_id.is_some(), "Struct should be registered");

        // Check implementors
        let has_implementors = ctx
            .code_graph
            .implementors_of(trait_id.unwrap())
            .next()
            .is_some();
        assert!(
            has_implementors,
            "MyTrait should have at least one implementor"
        );
    }

    #[test]
    fn test_uses_edge_from_struct_field() {
        let workspace = TestWorkspace::builder()
            .crate_with_source(
                "mylib",
                "src/lib.rs",
                r#"
                pub struct Inner {}

                pub struct Outer {
                    pub inner: Inner,
                }
                "#,
            )
            .build();

        let ctx = build_context_from_workspace(&workspace, "mylib");

        let outer_path = SymbolPath::parse("mylib::Outer").unwrap();
        let inner_path = SymbolPath::parse("mylib::Inner").unwrap();

        let outer_id = ctx.registry.lookup(&outer_path);
        let inner_id = ctx.registry.lookup(&inner_path);

        assert!(outer_id.is_some(), "Outer should be registered");
        assert!(inner_id.is_some(), "Inner should be registered");

        // Check type usage: Outer uses Inner (via TypeFlow)
        let outer = outer_id.unwrap();
        let is_user = ctx
            .typeflow_graph
            .type_users(inner_id.unwrap())
            .any(|id| id == outer);
        assert!(is_user, "Outer should use Inner");
    }

    #[test]
    fn test_uses_edge_from_fn_params() {
        let workspace = TestWorkspace::builder()
            .crate_with_source(
                "mylib",
                "src/lib.rs",
                r#"
                pub struct Config {}

                pub fn process(config: Config) {}
                "#,
            )
            .build();

        let ctx = build_context_from_workspace(&workspace, "mylib");

        let fn_path = SymbolPath::parse("mylib::process").unwrap();
        let config_path = SymbolPath::parse("mylib::Config").unwrap();

        let fn_id = ctx.registry.lookup(&fn_path);
        let config_id = ctx.registry.lookup(&config_path);

        assert!(fn_id.is_some(), "Function should be registered");
        assert!(config_id.is_some(), "Config should be registered");

        // Check type usage: process uses Config (via TypeFlow)
        let fn_sym = fn_id.unwrap();
        let config_sym = config_id.unwrap();

        let is_user = ctx
            .typeflow_graph
            .type_users(config_sym)
            .any(|id| id == fn_sym);
        assert!(is_user, "process should use Config");
    }

    #[test]
    fn test_calls_edge() {
        let workspace = TestWorkspace::builder()
            .crate_with_source(
                "mylib",
                "src/lib.rs",
                r#"
                pub fn helper() {}

                pub fn main_fn() {
                    helper();
                }
                "#,
            )
            .build();

        let ctx = build_context_from_workspace(&workspace, "mylib");

        let main_path = SymbolPath::parse("mylib::main_fn").unwrap();
        let helper_path = SymbolPath::parse("mylib::helper").unwrap();

        let main_id = ctx.registry.lookup(&main_path);
        let helper_id = ctx.registry.lookup(&helper_path);

        assert!(main_id.is_some(), "main_fn should be registered");
        assert!(helper_id.is_some(), "helper should be registered");

        // Check Calls edge: main_fn calls helper
        let main = main_id.unwrap();
        let is_caller = ctx
            .code_graph
            .callers_of(helper_id.unwrap())
            .any(|id| id == main);
        assert!(is_caller, "main_fn should call helper");
    }

    #[test]
    fn test_fork_clone_creates_independent_context() {
        let workspace = TestWorkspace::builder()
            .crate_with_source("mylib", "src/lib.rs", "pub fn foo() {}")
            .build();

        let original = build_context_from_workspace(&workspace, "mylib");
        let cloned = original.fork_clone();

        // Cloned has its own registry (different memory address)
        assert!(!std::ptr::eq(
            &original.registry as *const _,
            &cloned.registry as *const _
        ));

        // But same content
        assert_eq!(original.registry.len(), cloned.registry.len());
        assert_eq!(
            original.code_graph.node_count(),
            cloned.code_graph.node_count()
        );
    }

    #[test]
    fn test_fork_clone_is_faster_than_rebuild() {
        use std::time::Instant;

        // Create a context with multiple files
        let workspace = TestWorkspace::builder()
            .crate_with_source("mylib", "src/lib.rs", "pub mod a; pub mod b;")
            .crate_with_source("mylib", "src/a.rs", "pub struct A { x: i32 }")
            .crate_with_source("mylib", "src/b.rs", "pub struct B { y: String }")
            .build();

        let ctx = build_context_from_workspace(&workspace, "mylib");

        // Warm up
        let _ = ctx.fork_clone();
        let _ = ctx.fork_rebuild();

        // Benchmark fork_clone (10 iterations)
        let t0 = Instant::now();
        for _ in 0..10 {
            let _ = ctx.fork_clone();
        }
        let clone_time = t0.elapsed();

        // Benchmark fork_rebuild (10 iterations)
        let t1 = Instant::now();
        for _ in 0..10 {
            let _ = ctx.fork_rebuild();
        }
        let rebuild_time = t1.elapsed();

        eprintln!(
            "fork_clone: {:?} avg, fork_rebuild: {:?} avg, speedup: {:.1}x",
            clone_time / 10,
            rebuild_time / 10,
            rebuild_time.as_nanos() as f64 / clone_time.as_nanos() as f64
        );

        // fork_clone should be significantly faster
        assert!(
            clone_time < rebuild_time,
            "fork_clone ({:?}) should be faster than fork_rebuild ({:?})",
            clone_time,
            rebuild_time
        );
    }

    // ========================================================================
    // UUID Persistence Tests
    // ========================================================================

    #[test]
    fn test_uuid_persistence_save_and_load() {
        use ryo_symbol::SymbolPath;

        let temp_dir = tempfile::tempdir().expect("Failed to create temp dir");
        let workspace_root: Arc<Path> = Arc::from(temp_dir.path());

        // Create .ryo directory for UUID storage
        std::fs::create_dir_all(temp_dir.path().join(".ryo")).unwrap();

        // Create test files using TestWorkspace pattern
        let wfp = WorkspaceFilePath::new_for_test("src/lib.rs", temp_dir.path(), "test_crate");

        let source = r#"pub struct TestStruct { pub field: i32 }"#;
        let file = PureFile::from_source(source).expect("Failed to parse");

        let mut files = HashMap::new();
        files.insert(wfp.clone(), file);

        // Build first context (generates UUIDs)
        let ctx1 = AnalysisContext::build_from_workspace_files(
            files.clone(),
            workspace_root.clone(),
            AnalysisConfig::default(),
        )
        .unwrap();

        // Find TestStruct
        let path = SymbolPath::parse("test_crate::TestStruct").unwrap();
        let id1 = ctx1
            .registry
            .lookup(&path)
            .expect("TestStruct should be registered");
        let uuid1 = ctx1.registry.uuid(id1).expect("Should have UUID");

        // Save UUID mappings
        ctx1.save_uuid_mappings().expect("Failed to save");

        // Verify file exists
        let uuid_file = temp_dir.path().join(".ryo/uuid-mapping.json");
        assert!(uuid_file.exists(), "UUID file should exist");

        // Load mappings for second context
        let mappings =
            AnalysisContext::load_uuid_mappings(temp_dir.path()).expect("Should load mappings");

        // Rebuild with loaded mappings
        let config = AnalysisConfig::default().with_uuid_mappings(mappings);
        let ctx2 =
            AnalysisContext::build_from_workspace_files(files, workspace_root, config).unwrap();

        // Find TestStruct again (different SymbolId)
        let id2 = ctx2
            .registry
            .lookup(&path)
            .expect("TestStruct should exist");
        let uuid2 = ctx2.registry.uuid(id2).expect("Should have UUID");

        // UUID should be preserved
        assert_eq!(uuid1, uuid2, "UUID should be preserved across rebuilds");
    }

    #[test]
    fn test_uuid_persistence_new_symbol_gets_new_uuid() {
        use ryo_symbol::SymbolPath;

        let temp_dir = tempfile::tempdir().expect("Failed to create temp dir");
        let workspace_root: Arc<Path> = Arc::from(temp_dir.path());
        std::fs::create_dir_all(temp_dir.path().join(".ryo")).unwrap();

        let wfp = WorkspaceFilePath::new_for_test("src/lib.rs", temp_dir.path(), "test_crate");

        // First context with one struct
        let source1 = "pub struct First;";
        let file1 = PureFile::from_source(source1).unwrap();
        let mut files1 = HashMap::new();
        files1.insert(wfp.clone(), file1);

        let ctx1 = AnalysisContext::build_from_workspace_files(
            files1,
            workspace_root.clone(),
            AnalysisConfig::default(),
        )
        .unwrap();

        let first_path = SymbolPath::parse("test_crate::First").unwrap();
        let first_id = ctx1.registry.lookup(&first_path).unwrap();
        let first_uuid = ctx1.registry.uuid(first_id).unwrap();
        ctx1.save_uuid_mappings().unwrap();

        // Second context with two structs
        let source2 = "pub struct First;\npub struct Second;";
        let file2 = PureFile::from_source(source2).unwrap();
        let mut files2 = HashMap::new();
        files2.insert(wfp, file2);

        let mappings = AnalysisContext::load_uuid_mappings(temp_dir.path()).unwrap();
        let config = AnalysisConfig::default().with_uuid_mappings(mappings);
        let ctx2 =
            AnalysisContext::build_from_workspace_files(files2, workspace_root, config).unwrap();

        // First should keep UUID
        let first_id2 = ctx2.registry.lookup(&first_path).unwrap();
        let first_uuid2 = ctx2.registry.uuid(first_id2).unwrap();
        assert_eq!(first_uuid, first_uuid2, "First UUID preserved");

        // Second should have new UUID
        let second_path = SymbolPath::parse("test_crate::Second").unwrap();
        let second_id = ctx2.registry.lookup(&second_path).unwrap();
        let second_uuid = ctx2.registry.uuid(second_id).unwrap();
        assert_ne!(first_uuid, second_uuid, "Second has different UUID");
    }

    // ========================================================================
    // Core Entity: impl methods registered directly on struct
    // ========================================================================

    #[test]
    fn test_impl_methods_registered_directly_on_struct() {
        let workspace = TestWorkspace::builder()
            .crate_with_source(
                "mylib",
                "src/lib.rs",
                r#"
                pub struct TodoList {
                    items: Vec<String>,
                }

                impl TodoList {
                    pub fn new() -> Self {
                        Self { items: vec![] }
                    }

                    pub fn add(&mut self, item: String) {
                        self.items.push(item);
                    }
                }
                "#,
            )
            .build();

        let ctx = build_context_from_workspace(&workspace, "mylib");

        // メソッドが直接Structパスで登録される（implブロック経由なし）
        let new_path = SymbolPath::parse("mylib::TodoList::new").unwrap();
        let add_path = SymbolPath::parse("mylib::TodoList::add").unwrap();

        assert!(
            ctx.registry.lookup(&new_path).is_some(),
            "new method should be registered as TodoList::new"
        );
        assert!(
            ctx.registry.lookup(&add_path).is_some(),
            "add method should be registered as TodoList::add"
        );

        // impl block自体も登録される（trait操作のため）
        let impl_blocks: Vec<_> = ctx
            .registry
            .iter()
            .filter(|(_, path)| path.segment_refs().iter().any(|s| s.is_impl()))
            .collect();

        assert_eq!(
            impl_blocks.len(),
            1,
            "impl block should be registered as <impl TodoList>"
        );
        assert!(
            impl_blocks[0].1.to_string() == "mylib::<impl TodoList>",
            "impl block path should be mylib::<impl TodoList>, found: {}",
            impl_blocks[0].1
        );
    }

    #[test]
    fn test_multiple_impl_blocks_methods_merged_on_struct() {
        let workspace = TestWorkspace::builder()
            .crate_with_source(
                "mylib",
                "src/lib.rs",
                r#"
                pub struct TodoList;

                impl TodoList {
                    pub fn new() -> Self { Self }
                }

                impl TodoList {
                    pub fn add(&mut self, item: String) {}
                }
                "#,
            )
            .build();

        let ctx = build_context_from_workspace(&workspace, "mylib");

        // 両方のimplブロックのメソッドがStructに登録される
        let new_path = SymbolPath::parse("mylib::TodoList::new").unwrap();
        let add_path = SymbolPath::parse("mylib::TodoList::add").unwrap();

        assert!(
            ctx.registry.lookup(&new_path).is_some(),
            "new from first impl should be registered"
        );
        assert!(
            ctx.registry.lookup(&add_path).is_some(),
            "add from second impl should be registered"
        );

        // impl blockがマージされて1つ登録される
        let impl_blocks: Vec<_> = ctx
            .registry
            .iter()
            .filter(|(_, path)| path.segment_refs().iter().any(|s| s.is_impl()))
            .collect();

        assert_eq!(
            impl_blocks.len(),
            1,
            "merged impl block should be registered"
        );
        assert!(
            impl_blocks[0].1.to_string() == "mylib::<impl TodoList>",
            "impl block path should be mylib::<impl TodoList>"
        );
    }

    // =====================================================================
    // BUG#3: graph chain callers/callees resolution tests
    // =====================================================================

    /// P0: Associated function call across modules via `use` import.
    /// `Router::new()` in handler.rs should create a Calls edge to types::Router::new.
    #[test]
    fn test_calls_edge_associated_fn_cross_module() {
        let workspace = TestWorkspace::builder()
            .crate_with_source(
                "mylib",
                "src/lib.rs",
                r#"
                pub mod types;
                pub mod handler;
                "#,
            )
            .crate_with_source(
                "mylib",
                "src/types.rs",
                r#"
                pub struct Router {}
                impl Router {
                    pub fn new() -> Self { Router {} }
                }
                "#,
            )
            .crate_with_source(
                "mylib",
                "src/handler.rs",
                r#"
                use crate::types::Router;
                pub fn setup() {
                    let _r = Router::new();
                }
                "#,
            )
            .build();

        let ctx = build_context_from_workspace(&workspace, "mylib");

        let setup_path = SymbolPath::parse("mylib::handler::setup").unwrap();
        let new_path = SymbolPath::parse("mylib::types::Router::new").unwrap();

        let setup_id = ctx
            .registry
            .lookup(&setup_path)
            .expect("setup should be registered");
        let new_id = ctx
            .registry
            .lookup(&new_path)
            .expect("Router::new should be registered");

        let callees: Vec<_> = ctx.code_graph.callees_of(setup_id).collect();
        assert!(
            callees.contains(&new_id),
            "setup should call Router::new, but callees = {:?}",
            callees
        );
    }

    /// P0: Cross-module free function call via `use` import.
    #[test]
    fn test_calls_edge_free_fn_cross_module_via_use() {
        let workspace = TestWorkspace::builder()
            .crate_with_source(
                "mylib",
                "src/lib.rs",
                r#"
                pub mod utils;
                pub mod handler;
                "#,
            )
            .crate_with_source(
                "mylib",
                "src/utils.rs",
                r#"
                pub fn helper() {}
                "#,
            )
            .crate_with_source(
                "mylib",
                "src/handler.rs",
                r#"
                use crate::utils::helper;
                pub fn process() {
                    helper();
                }
                "#,
            )
            .build();

        let ctx = build_context_from_workspace(&workspace, "mylib");

        let process_path = SymbolPath::parse("mylib::handler::process").unwrap();
        let helper_path = SymbolPath::parse("mylib::utils::helper").unwrap();

        let process_id = ctx
            .registry
            .lookup(&process_path)
            .expect("process should be registered");
        let helper_id = ctx
            .registry
            .lookup(&helper_path)
            .expect("helper should be registered");

        let is_callee = ctx
            .code_graph
            .callees_of(process_id)
            .any(|id| id == helper_id);
        assert!(is_callee, "process should call helper via use import");
    }

    /// P1: Method call `self.method()` where method name is in common trait list ("new").
    /// Associated function calls (Type::new()) should NOT be filtered by is_common_trait_method.
    #[test]
    fn test_calls_edge_associated_fn_new_not_filtered() {
        let workspace = TestWorkspace::builder()
            .crate_with_source(
                "mylib",
                "src/lib.rs",
                r#"
                pub struct Builder {}
                impl Builder {
                    pub fn new() -> Self { Builder {} }
                    pub fn build(self) -> String { String::new() }
                }

                pub fn create() -> String {
                    let b = Builder::new();
                    b.build()
                }
                "#,
            )
            .build();

        let ctx = build_context_from_workspace(&workspace, "mylib");

        let create_path = SymbolPath::parse("mylib::create").unwrap();
        let new_path = SymbolPath::parse("mylib::Builder::new").unwrap();

        let create_id = ctx
            .registry
            .lookup(&create_path)
            .expect("create should be registered");
        let new_id = ctx
            .registry
            .lookup(&new_path)
            .expect("Builder::new should be registered");

        let callees: Vec<_> = ctx.code_graph.callees_of(create_id).collect();
        assert!(
            callees.contains(&new_id),
            "create should call Builder::new (associated fn, not filtered by is_common_trait_method), callees = {:?}",
            callees
        );
    }

    /// P0: Qualified path call with multiple segments (e.g., `module::func()`).
    #[test]
    fn test_calls_edge_qualified_path_call() {
        let workspace = TestWorkspace::builder()
            .crate_with_source(
                "mylib",
                "src/lib.rs",
                r#"
                pub mod utils {
                    pub fn do_work() {}
                }

                pub fn caller() {
                    utils::do_work();
                }
                "#,
            )
            .build();

        let ctx = build_context_from_workspace(&workspace, "mylib");

        let caller_path = SymbolPath::parse("mylib::caller").unwrap();
        let do_work_path = SymbolPath::parse("mylib::utils::do_work").unwrap();

        let caller_id = ctx
            .registry
            .lookup(&caller_path)
            .expect("caller should be registered");
        let do_work_id = ctx
            .registry
            .lookup(&do_work_path)
            .expect("do_work should be registered");

        let is_callee = ctx
            .code_graph
            .callees_of(caller_id)
            .any(|id| id == do_work_id);
        assert!(
            is_callee,
            "caller should call utils::do_work via qualified path"
        );
    }

    /// P1: Method call with common trait name ("clone") should resolve
    /// when there is exactly one candidate (unambiguous).
    #[test]
    fn test_calls_edge_method_common_name_single_candidate() {
        let workspace = TestWorkspace::builder()
            .crate_with_source(
                "mylib",
                "src/lib.rs",
                r#"
                pub struct Data {}
                impl Data {
                    pub fn clone(&self) -> Self { Data {} }
                }

                pub fn process(d: Data) -> Data {
                    d.clone()
                }
                "#,
            )
            .build();

        let ctx = build_context_from_workspace(&workspace, "mylib");

        let process_path = SymbolPath::parse("mylib::process").unwrap();
        let clone_path = SymbolPath::parse("mylib::Data::clone").unwrap();

        let process_id = ctx
            .registry
            .lookup(&process_path)
            .expect("process should be registered");
        let clone_id = ctx
            .registry
            .lookup(&clone_path)
            .expect("Data::clone should be registered");

        let callees: Vec<_> = ctx.code_graph.callees_of(process_id).collect();
        assert!(
            callees.contains(&clone_id),
            "process should call Data::clone even though 'clone' is in common trait list (single candidate), callees = {:?}",
            callees
        );
    }

    /// P1: Candidate limit should not block resolution when candidates <= 32.
    #[test]
    fn test_calls_edge_method_many_candidates_not_blocked() {
        // Create 12 types each with a "handle" method — exceeds old limit of 8
        let workspace = TestWorkspace::builder()
            .crate_with_source(
                "mylib",
                "src/lib.rs",
                r#"
                pub struct A {} impl A { pub fn handle(&self) {} }
                pub struct B {} impl B { pub fn handle(&self) {} }
                pub struct C {} impl C { pub fn handle(&self) {} }
                pub struct D {} impl D { pub fn handle(&self) {} }
                pub struct E {} impl E { pub fn handle(&self) {} }
                pub struct F {} impl F { pub fn handle(&self) {} }
                pub struct G {} impl G { pub fn handle(&self) {} }
                pub struct H {} impl H { pub fn handle(&self) {} }
                pub struct I {} impl I { pub fn handle(&self) {} }
                pub struct J {} impl J { pub fn handle(&self) {} }
                pub struct K {} impl K { pub fn handle(&self) {} }
                pub struct L {} impl L { pub fn handle(&self) {} }

                pub fn caller(a: A) {
                    a.handle();
                }
                "#,
            )
            .build();

        let ctx = build_context_from_workspace(&workspace, "mylib");

        let caller_path = SymbolPath::parse("mylib::caller").unwrap();
        let caller_id = ctx
            .registry
            .lookup(&caller_path)
            .expect("caller should be registered");

        let callees: Vec<_> = ctx.code_graph.callees_of(caller_id).collect();
        // Without type inference, all 12 "handle" methods are candidates (over-approximation).
        // The key assertion: at least some callees exist (not 0 due to candidate cap).
        assert!(
            !callees.is_empty(),
            "caller should have callees for 'handle' method (12 candidates should not be blocked), callees = {:?}",
            callees
        );
    }

    /// Trait impl method body should have callees resolved
    /// (direct function call inside trait impl).
    #[test]
    fn test_calls_edge_trait_impl_method_has_callees() {
        let workspace = TestWorkspace::builder()
            .crate_with_source(
                "mylib",
                "src/lib.rs",
                r#"
                pub fn helper() -> i32 { 42 }

                pub trait MyTrait {
                    fn do_work(&self) -> i32;
                }

                pub struct Foo;
                impl MyTrait for Foo {
                    fn do_work(&self) -> i32 {
                        helper()
                    }
                }
                "#,
            )
            .build();

        let ctx = build_context_from_workspace(&workspace, "mylib");

        // Verify symbols are registered
        let helper_path = SymbolPath::parse("mylib::helper").unwrap();
        let helper_id = ctx
            .registry
            .lookup(&helper_path)
            .expect("helper should be registered");

        let method_path = SymbolPath::parse("mylib::<impl MyTrait for Foo>::do_work").unwrap();
        let method_id = ctx
            .registry
            .lookup(&method_path)
            .expect("trait impl method should be registered");

        let callees: Vec<_> = ctx.code_graph.callees_of(method_id).collect();
        assert!(
            callees.contains(&helper_id),
            "Trait impl method do_work should call helper(), but callees = {:?}",
            callees
        );
    }

    /// Trait impl method with self.method() call should have callees resolved.
    #[test]
    fn test_calls_edge_trait_impl_method_call_inside_body() {
        let workspace = TestWorkspace::builder()
            .crate_with_source(
                "mylib",
                "src/lib.rs",
                r#"
                pub struct Data {
                    pub value: i32,
                }
                impl Data {
                    pub fn process(&self) -> i32 { self.value }
                }

                pub trait Transform {
                    fn transform(&self) -> i32;
                }

                impl Transform for Data {
                    fn transform(&self) -> i32 {
                        self.process()
                    }
                }
                "#,
            )
            .build();

        let ctx = build_context_from_workspace(&workspace, "mylib");

        let transform_method_path =
            SymbolPath::parse("mylib::<impl Transform for Data>::transform").unwrap();
        let transform_id = ctx
            .registry
            .lookup(&transform_method_path)
            .expect("transform should be registered");

        let process_path = SymbolPath::parse("mylib::Data::process").unwrap();
        let process_id = ctx
            .registry
            .lookup(&process_path)
            .expect("Data::process should be registered");

        let callees: Vec<_> = ctx.code_graph.callees_of(transform_id).collect();
        assert!(
            callees.contains(&process_id),
            "Trait impl transform() should call self.process(), but callees = {:?}",
            callees
        );
    }

    /// Method call with >32 candidates should NOT be silently dropped.
    /// Reproduces axum `into_response` pattern: 57 impls caused 0 callees.
    #[test]
    fn test_calls_edge_method_over_32_candidates_not_dropped() {
        // Create 35 types each with a "render" method to exceed the limit of 32
        let mut source = String::new();
        for i in 0..35 {
            source.push_str(&format!(
                "pub struct T{i} {{}}\nimpl T{i} {{ pub fn render(&self) -> i32 {{ {i} }} }}\n"
            ));
        }
        source.push_str(
            r#"
            pub fn caller(t: T0) -> i32 {
                t.render()
            }
            "#,
        );

        let workspace = TestWorkspace::builder()
            .crate_with_source("mylib", "src/lib.rs", &source)
            .build();

        let ctx = build_context_from_workspace(&workspace, "mylib");

        let caller_path = SymbolPath::parse("mylib::caller").unwrap();
        let caller_id = ctx
            .registry
            .lookup(&caller_path)
            .expect("caller should be registered");

        let callees: Vec<_> = ctx.code_graph.callees_of(caller_id).collect();
        assert!(
            !callees.is_empty(),
            "caller should have callees for 'render' even with 35 candidates (>32 limit), \
             but callees is empty — candidate limit silently drops all edges"
        );
    }

    #[test]
    fn test_method_index_excludes_non_callable_symbols() {
        // BUG: method_index includes modules, structs, enums that share the method name.
        // When a nested module like "response::process" exists (3 segments = passes current filter),
        // calling x.process() should NOT create an edge to the module.
        // This mirrors axum's axum_core::response::into_response (module) vs .into_response() (method).
        let source = r#"
            pub mod response {
                pub mod process {
                    pub fn run() -> i32 { 42 }
                }
            }
            pub struct Engine;
            impl Engine {
                pub fn process(&self) -> i32 { 1 }
            }
            pub fn caller(e: Engine) -> i32 {
                e.process()
            }
        "#;

        let workspace = TestWorkspace::builder()
            .crate_with_source("mylib", "src/lib.rs", source)
            .build();

        let ctx = build_context_from_workspace(&workspace, "mylib");

        let caller_path = SymbolPath::parse("mylib::caller").unwrap();
        let caller_id = ctx
            .registry
            .lookup(&caller_path)
            .expect("caller should be registered");

        let callees: Vec<_> = ctx.code_graph.callees_of(caller_id).collect();

        // The nested module "response::process" should NOT be a callee
        let mod_path = SymbolPath::parse("mylib::response::process").unwrap();
        let mod_id = ctx
            .registry
            .lookup(&mod_path)
            .expect("nested module mylib::response::process should be registered");

        let has_mod_edge = callees.contains(&mod_id);
        assert!(
            !has_mod_edge,
            "method_index should not include module 'response::process' as a callee of caller(); \
             only Function/Method symbols should be in the method_index"
        );

        // Engine::process SHOULD be a callee
        assert!(
            !callees.is_empty(),
            "caller should have at least one callee (Engine::process)"
        );
    }

    #[test]
    fn test_method_call_receiver_type_hint_filters_candidates() {
        // When the receiver is a constructor call like `Foo::new()`, we can infer
        // the receiver type is `Foo` and filter method_index candidates to only
        // methods on `Foo`, instead of ALL methods with the same name.
        let source = r#"
            pub trait Render {
                fn render(&self) -> String;
            }
            pub struct Html;
            impl Render for Html {
                fn render(&self) -> String { String::new() }
            }
            pub struct Json;
            impl Json {
                pub fn new() -> Self { Json }
            }
            impl Render for Json {
                fn render(&self) -> String { String::new() }
            }
            pub struct Xml;
            impl Render for Xml {
                fn render(&self) -> String { String::new() }
            }
            pub fn caller() -> String {
                Json::new().render()
            }
        "#;

        let workspace = TestWorkspace::builder()
            .crate_with_source("mylib", "src/lib.rs", source)
            .build();

        let ctx = build_context_from_workspace(&workspace, "mylib");

        let caller_path = SymbolPath::parse("mylib::caller").unwrap();
        let caller_id = ctx
            .registry
            .lookup(&caller_path)
            .expect("caller should be registered");

        let callees: Vec<_> = ctx.code_graph.callees_of(caller_id).collect();

        // Json::new should be a callee
        let new_path = SymbolPath::parse("mylib::Json::new").unwrap();
        let new_id = ctx.registry.lookup(&new_path);
        if let Some(new_id) = new_id {
            assert!(callees.contains(&new_id), "Json::new should be a callee");
        }

        // Json's render should be a callee (receiver = Json::new())
        // Html's render and Xml's render should NOT be callees
        // because we can infer the receiver type is Json from Json::new()
        let json_render = ctx
            .registry
            .lookup(&SymbolPath::parse("mylib::<impl Render for Json>::render").unwrap());
        let html_render = ctx
            .registry
            .lookup(&SymbolPath::parse("mylib::<impl Render for Html>::render").unwrap());
        let xml_render = ctx
            .registry
            .lookup(&SymbolPath::parse("mylib::<impl Render for Xml>::render").unwrap());

        if let Some(json_id) = json_render {
            assert!(
                callees.contains(&json_id),
                "Json's render should be a callee (receiver type hint: Json from Json::new())"
            );
        }

        // These should NOT be callees if receiver type hint works
        if let Some(html_id) = html_render {
            assert!(
                !callees.contains(&html_id),
                "Html's render should NOT be a callee when receiver is Json::new(); \
                 receiver type hint should filter it out"
            );
        }

        if let Some(xml_id) = xml_render {
            assert!(
                !callees.contains(&xml_id),
                "Xml's render should NOT be a callee when receiver is Json::new(); \
                 receiver type hint should filter it out"
            );
        }
    }

    #[test]
    fn test_associated_fn_call_in_trait_impl_resolved_via_imports() {
        // BUG: When Body::new() is called inside a trait impl method,
        // resolve_type_reference receives parent_path with impl segment
        // (e.g., "mylib::<impl Render for Page>::render") but UseResolver
        // stores import maps keyed by module path ("mylib"). The impl
        // segment causes import resolution to fail, so Body::new() is
        // not detected as a callee.
        let source = r#"
            pub mod types {
                pub struct Body;
                impl Body {
                    pub fn create() -> Self { Body }
                }
            }
            use crate::types::Body;
            pub trait Render {
                fn render(&self) -> Body;
            }
            pub struct Page;
            impl Render for Page {
                fn render(&self) -> Body {
                    Body::create()
                }
            }
        "#;

        let workspace = TestWorkspace::builder()
            .crate_with_source("mylib", "src/lib.rs", source)
            .build();

        let ctx = build_context_from_workspace(&workspace, "mylib");

        // Find Page's render method
        let render_path = SymbolPath::parse("mylib::<impl Render for Page>::render").unwrap();
        let render_id = ctx
            .registry
            .lookup(&render_path)
            .expect("Page::render should be registered");

        let callees: Vec<_> = ctx.code_graph.callees_of(render_id).collect();

        // Body::create should be a callee
        let create_path = SymbolPath::parse("mylib::types::Body::create").unwrap();
        let create_id = ctx
            .registry
            .lookup(&create_path)
            .expect("Body::create should be registered");

        assert!(
            callees.contains(&create_id),
            "Body::create() should be a callee of Page::render(); \
             import resolution in trait impl methods must strip impl segments \
             from parent_path before querying UseResolver"
        );
    }

    #[test]
    fn test_generic_impl_methods_registered_and_edges_built() {
        // BUG: impl<S> Router<S> { pub fn new() -> Self { ... } }
        // collect_from_impl AND build_edges_from_impl both call
        // parent.child("Router < S >") which fails validate_rust_identifier
        // → Err → return → methods never registered / edges never built.
        let workspace = TestWorkspace::builder()
            .crate_with_source(
                "mylib",
                "src/lib.rs",
                r#"
                pub struct Inner;
                impl Inner {
                    pub fn create() -> Self { Inner }
                }

                pub struct Router<S> {
                    _marker: std::marker::PhantomData<S>,
                }

                impl<S> Router<S> {
                    pub fn new() -> Self {
                        let _inner = Inner::create();
                        Router { _marker: std::marker::PhantomData }
                    }

                    pub fn route(self, path: &str) -> Self {
                        self
                    }
                }
                "#,
            )
            .build();

        let ctx = build_context_from_workspace(&workspace, "mylib");

        // Methods must be registered under the base type name (without generics)
        let new_path = SymbolPath::parse("mylib::Router::new").unwrap();
        let route_path = SymbolPath::parse("mylib::Router::route").unwrap();

        let new_id = ctx
            .registry
            .lookup(&new_path)
            .expect("Router::new should be registered despite generic impl<S> Router<S>");
        assert!(
            ctx.registry.lookup(&route_path).is_some(),
            "Router::route should be registered despite generic impl<S> Router<S>"
        );

        // impl block itself should also be registered
        let impl_path_str = "mylib::<impl Router < S >>";
        let impl_path = SymbolPath::parse(impl_path_str).unwrap();
        assert!(
            ctx.registry.lookup(&impl_path).is_some(),
            "impl block <impl Router < S >> should be registered"
        );

        // Callees edges must also be built for generic impl methods
        let callees: Vec<_> = ctx.code_graph.callees_of(new_id).collect();
        let create_path = SymbolPath::parse("mylib::Inner::create").unwrap();
        let create_id = ctx
            .registry
            .lookup(&create_path)
            .expect("Inner::create should be registered");
        assert!(
            callees.contains(&create_id),
            "Router::new must have Inner::create() as callee; \
             build_edges_from_impl must strip generics from self_ty"
        );
    }

    #[test]
    fn test_external_trait_impl_callees_built() {
        // NG-6: impl ExternalTrait for LocalType のメソッドのcalleesが0になる問題
        // bodyでプロジェクト内関数を呼び出しているのに、calleesエッジが構築されない
        let workspace = TestWorkspace::builder()
            .crate_with_source(
                "mylib",
                "src/lib.rs",
                r#"
                pub trait MyWrite {
                    fn write(&mut self, buf: &[u8]) -> usize;
                }

                pub fn helper() -> usize { 42 }

                pub struct Writer;

                impl MyWrite for Writer {
                    fn write(&mut self, buf: &[u8]) -> usize {
                        helper()
                    }
                }
                "#,
            )
            .build();

        let ctx = build_context_from_workspace(&workspace, "mylib");

        // Method should be registered under impl path
        let impl_path_str = "mylib::<impl MyWrite for Writer>";
        let impl_path = SymbolPath::parse(impl_path_str).unwrap();
        assert!(
            ctx.registry.lookup(&impl_path).is_some(),
            "impl block should be registered: {}",
            impl_path_str,
        );

        let method_path = SymbolPath::parse(&format!("{}::write", impl_path_str)).unwrap();
        let method_id = ctx
            .registry
            .lookup(&method_path)
            .expect("Writer::write should be registered under trait impl path");

        // Callees should include helper()
        let callees: Vec<_> = ctx.code_graph.callees_of(method_id).collect();
        let helper_path = SymbolPath::parse("mylib::helper").unwrap();
        let helper_id = ctx
            .registry
            .lookup(&helper_path)
            .expect("helper should be registered");

        assert!(
            callees.contains(&helper_id),
            "trait impl method Writer::write must have helper() as callee; \
             callees = {:?}",
            callees
        );
    }

    #[test]
    fn test_external_trait_impl_with_generics_callees_built() {
        // NG-6の亜種: impl ExternalTrait for GenericType<'_>
        let workspace = TestWorkspace::builder()
            .crate_with_source(
                "mylib",
                "src/lib.rs",
                r#"
                pub trait MyWrite {
                    fn write(&mut self, buf: &[u8]) -> usize;
                }

                pub fn process_buf(buf: &[u8]) -> usize { buf.len() }

                pub struct Writer<'a> {
                    _data: &'a [u8],
                }

                impl<'a> MyWrite for Writer<'a> {
                    fn write(&mut self, buf: &[u8]) -> usize {
                        process_buf(buf)
                    }
                }
                "#,
            )
            .build();

        let ctx = build_context_from_workspace(&workspace, "mylib");

        // Check impl block registration with lifetime param
        let impl_path_str = "mylib::<impl MyWrite for Writer < 'a >>";
        let impl_path = SymbolPath::parse(impl_path_str).unwrap();
        let impl_registered = ctx.registry.lookup(&impl_path).is_some();

        // Method should be registered
        let method_path = SymbolPath::parse(&format!("{}::write", impl_path_str)).unwrap();
        let method_id = ctx.registry.lookup(&method_path);

        assert!(
            impl_registered,
            "impl block <impl MyWrite for Writer < 'a >> should be registered"
        );
        assert!(
            method_id.is_some(),
            "Writer::write should be registered under trait impl path"
        );

        if let Some(mid) = method_id {
            let callees: Vec<_> = ctx.code_graph.callees_of(mid).collect();
            let process_path = SymbolPath::parse("mylib::process_buf").unwrap();
            let process_id = ctx
                .registry
                .lookup(&process_path)
                .expect("process_buf should be registered");

            assert!(
                callees.contains(&process_id),
                "trait impl method with generics must have process_buf() as callee; \
                 callees = {:?}",
                callees
            );
        }
    }

    /// NG-2: Struct → Impl → Trait のチェーン追跡に必要なグラフ構造の検証
    #[test]
    fn test_struct_trait_implements_chain_via_impl() {
        let workspace = TestWorkspace::builder()
            .crate_with_source(
                "mylib",
                "src/lib.rs",
                r#"
                pub trait MyTrait {
                    fn do_something(&self);
                }

                pub trait AnotherTrait {
                    fn other(&self);
                }

                pub struct MyStruct;

                impl MyTrait for MyStruct {
                    fn do_something(&self) {}
                }

                impl AnotherTrait for MyStruct {
                    fn other(&self) {}
                }
                "#,
            )
            .build();

        let ctx = build_context_from_workspace(&workspace, "mylib");

        // Verify graph structure: Impl blocks have Implements edges to Traits
        let impl_mytrait_path = SymbolPath::parse("mylib::<impl MyTrait for MyStruct>").unwrap();
        let impl_another_path =
            SymbolPath::parse("mylib::<impl AnotherTrait for MyStruct>").unwrap();
        let mytrait_path = SymbolPath::parse("mylib::MyTrait").unwrap();
        let another_path = SymbolPath::parse("mylib::AnotherTrait").unwrap();
        let struct_path = SymbolPath::parse("mylib::MyStruct").unwrap();

        let impl_mytrait_id = ctx
            .registry
            .lookup(&impl_mytrait_path)
            .expect("impl MyTrait for MyStruct should be registered");
        let impl_another_id = ctx
            .registry
            .lookup(&impl_another_path)
            .expect("impl AnotherTrait for MyStruct should be registered");
        let mytrait_id = ctx
            .registry
            .lookup(&mytrait_path)
            .expect("MyTrait should be registered");
        let another_id = ctx
            .registry
            .lookup(&another_path)
            .expect("AnotherTrait should be registered");
        let struct_id = ctx
            .registry
            .lookup(&struct_path)
            .expect("MyStruct should be registered");

        // Impl → Trait edges exist
        let impl1_targets: Vec<_> = ctx
            .code_graph
            .outgoing_edges(impl_mytrait_id)
            .filter(|e| e.kind == CodeEdgeV2::Implements)
            .map(|e| e.to)
            .collect();
        assert!(
            impl1_targets.contains(&mytrait_id),
            "impl MyTrait for MyStruct should have Implements edge to MyTrait"
        );

        let impl2_targets: Vec<_> = ctx
            .code_graph
            .outgoing_edges(impl_another_id)
            .filter(|e| e.kind == CodeEdgeV2::Implements)
            .map(|e| e.to)
            .collect();
        assert!(
            impl2_targets.contains(&another_id),
            "impl AnotherTrait for MyStruct should have Implements edge to AnotherTrait"
        );

        // Struct has NO direct Implements edges (this is the expected structure)
        let struct_implements: Vec<_> = ctx
            .code_graph
            .outgoing_edges(struct_id)
            .filter(|e| e.kind == CodeEdgeV2::Implements)
            .collect();
        assert!(
            struct_implements.is_empty(),
            "Struct should have no direct Implements edges; chain via Impl is needed"
        );

        // Verify chain: Struct name can be matched against Impl self_ty
        let struct_name = struct_path.name();
        let impl_ids_for_struct: Vec<_> = ctx
            .registry
            .iter_by_kind(SymbolKind::Impl)
            .filter(|&id| {
                ctx.registry
                    .resolve(id)
                    .and_then(|p| p.segment_refs().last())
                    .and_then(|seg| seg.impl_self_ty())
                    .map(|ty| ty.split('<').next().unwrap_or(ty).trim() == struct_name)
                    .unwrap_or(false)
            })
            .collect();
        assert_eq!(
            impl_ids_for_struct.len(),
            2,
            "MyStruct should have 2 impl blocks"
        );

        // Follow Implements edges from matching Impl blocks → Traits
        let mut trait_ids: Vec<_> = impl_ids_for_struct
            .iter()
            .flat_map(|&impl_id| {
                ctx.code_graph
                    .outgoing_edges(impl_id)
                    .filter(|e| e.kind == CodeEdgeV2::Implements)
                    .map(|e| e.to)
                    .collect::<Vec<_>>()
            })
            .collect();
        trait_ids.sort();
        trait_ids.dedup();

        assert!(
            trait_ids.contains(&mytrait_id),
            "Struct → Impl → Trait chain should reach MyTrait"
        );
        assert!(
            trait_ids.contains(&another_id),
            "Struct → Impl → Trait chain should reach AnotherTrait"
        );

        // Verify ImplementedBy reverse: Trait → Impl, Impl self_ty → Struct
        let implementors: Vec<_> = ctx.code_graph.implementors_of(mytrait_id).collect();
        assert!(
            implementors.contains(&impl_mytrait_id),
            "MyTrait should have impl block as implementor"
        );

        // Resolve Impl → Struct by matching self_ty name
        for &impl_id in &implementors {
            if let Some(impl_path) = ctx.registry.resolve(impl_id) {
                if let Some(last_seg) = impl_path.segment_refs().last() {
                    if let Some(self_ty) = last_seg.impl_self_ty() {
                        let base = self_ty.split('<').next().unwrap_or(self_ty).trim();
                        let resolved_struct = ctx.registry.lookup_by_name(base);
                        assert!(
                            resolved_struct.is_some(),
                            "Impl self_ty '{}' should resolve to a registered struct",
                            base
                        );
                        assert_eq!(
                            resolved_struct.unwrap(),
                            struct_id,
                            "Impl self_ty should resolve to MyStruct"
                        );
                    }
                }
            }
        }
    }

    /// NG-4: self.method() で parent_path から self_ty を抽出してtype_hintとして使用
    #[test]
    fn test_self_method_resolves_via_impl_type_hint() {
        // self.render() in trait impl should resolve to inherent render(), not all render()
        let workspace = TestWorkspace::builder()
            .crate_with_source(
                "mylib",
                "src/lib.rs",
                r#"
                pub trait IntoResponse {
                    fn into_response(self) -> String;
                }

                pub struct Html {
                    content: String,
                }

                impl Html {
                    pub fn render(&self) -> String {
                        self.content.clone()
                    }
                }

                pub struct Json {
                    data: String,
                }

                impl Json {
                    pub fn render(&self) -> String {
                        self.data.clone()
                    }
                }

                impl IntoResponse for Html {
                    fn into_response(self) -> String {
                        self.render()
                    }
                }
                "#,
            )
            .build();

        let ctx = build_context_from_workspace(&workspace, "mylib");

        let into_response_path =
            SymbolPath::parse("mylib::<impl IntoResponse for Html>::into_response").unwrap();
        let html_render_path = SymbolPath::parse("mylib::Html::render").unwrap();
        let json_render_path = SymbolPath::parse("mylib::Json::render").unwrap();

        let into_response_id = ctx
            .registry
            .lookup(&into_response_path)
            .expect("into_response should be registered");
        let html_render_id = ctx
            .registry
            .lookup(&html_render_path)
            .expect("Html::render should be registered");
        let json_render_id = ctx
            .registry
            .lookup(&json_render_path)
            .expect("Json::render should be registered");

        let callees: Vec<_> = ctx.code_graph.callees_of(into_response_id).collect();

        // self.render() in impl IntoResponse for Html should resolve to Html::render,
        // NOT Json::render (which is a different type's render method)
        assert!(
            callees.contains(&html_render_id),
            "self.render() in Html's trait impl should resolve to Html::render; \
             callees = {:?}",
            callees
        );
        assert!(
            !callees.contains(&json_render_id),
            "self.render() in Html's trait impl should NOT resolve to Json::render; \
             callees = {:?}",
            callees
        );
    }

    #[test]
    fn test_extract_self_type_from_parent_path() {
        // Trait impl
        assert_eq!(
            extract_self_type_from_parent_path("mylib::<impl IntoResponse for Html>"),
            Some("Html")
        );
        // Trait impl with generics
        assert_eq!(
            extract_self_type_from_parent_path("mylib::<impl io::Write for Writer < '_ >>"),
            Some("Writer")
        );
        // Inherent impl
        assert_eq!(
            extract_self_type_from_parent_path("mylib::<impl Router < S >>"),
            Some("Router")
        );
        // Plain type path
        assert_eq!(
            extract_self_type_from_parent_path("mylib::Html"),
            Some("Html")
        );
    }
}