tftio-prompter 3.0.0

//! Profile resolution, dependency trees, and listing.
use crate::config::Config;
use crate::config::load_bundle;
use crate::{
    ProfileDef, PrompterError, home_dir, parse_config_file, read_config_with_path, unescape,
};
use serde::{Deserialize, Serialize};
use std::collections::HashMap;
use std::collections::HashSet;
use std::fs;
use std::io;
use std::io::Write;
use std::path::{Path, PathBuf};
use tftio_cli_common::{JsonOutput, render_response};

pub(crate) fn collect_profiles(
    prefix: &str,
    value: &toml::Value,
    out: &mut HashMap<String, Vec<String>>,
) -> Result<(), PrompterError> {
    let Some(table) = value.as_table() else {
        return Ok(());
    };

    if let Some(deps_value) = table.get("depends_on") {
        let arr = deps_value.as_array().ok_or_else(|| {
            PrompterError::ConfigField(format!(
                "`depends_on` for [{prefix}] must be an array of strings"
            ))
        })?;
        let mut deps = Vec::with_capacity(arr.len());
        for entry in arr {
            let s = entry.as_str().ok_or_else(|| {
                PrompterError::ConfigField(format!(
                    "`depends_on` entries for [{prefix}] must be strings"
                ))
            })?;
            deps.push(s.to_string());
        }
        if out.insert(prefix.to_string(), deps).is_some() {
            return Err(PrompterError::DuplicateProfile(format!(
                "Duplicate profile definition: [{prefix}]"
            )));
        }
    }

    for (sub_key, sub_val) in table {
        if sub_key == "depends_on" {
            continue;
        }
        let new_prefix = if prefix.is_empty() {
            sub_key.clone()
        } else {
            format!("{prefix}.{sub_key}")
        };
        collect_profiles(&new_prefix, sub_val, out)?;
    }
    Ok(())
}

/// Expand a leading `~` or `~/` to the home directory.
///
/// Paths without a leading `~` are returned unchanged.
pub(crate) fn expand_tilde(s: &str) -> Result<PathBuf, PrompterError> {
    if let Some(rest) = s.strip_prefix("~/") {
        Ok(home_dir()?.join(rest))
    } else if s == "~" {
        home_dir()
    } else {
        Ok(PathBuf::from(s))
    }
}

/// Resolve an `import = [...]` entry against the importing config's directory.
///
/// Absolute paths are returned as-is (after `~` expansion); relative paths
/// are joined onto `importer_dir`.
fn resolve_import_path(importer_dir: &Path, import_str: &str) -> Result<PathBuf, PrompterError> {
    let p = expand_tilde(import_str)?;
    if p.is_absolute() {
        Ok(p)
    } else {
        Ok(importer_dir.join(p))
    }
}

/// Determine the library root for a loaded config file.
///
/// * If the config has an explicit `library = "..."` key, expand tilde and
///   resolve it relative to the config file's directory.
/// * Otherwise, if `default_library` is provided (only the primary config
///   with no `-c` override gets this), use that.
/// * Otherwise, default to `<config-dir>/library`.
fn library_root_for(
    config_path: &Path,
    raw_library: Option<&str>,
    default_library: Option<&Path>,
) -> Result<PathBuf, PrompterError> {
    let config_dir = config_path
        .parent()
        .ok_or_else(|| PrompterError::NoParentDir(config_path.to_path_buf()))?;

    if let Some(lib_str) = raw_library {
        let p = expand_tilde(lib_str)?;
        return Ok(if p.is_absolute() {
            p
        } else {
            config_dir.join(p)
        });
    }

    if let Some(default) = default_library {
        return Ok(default.to_path_buf());
    }

    Ok(config_dir.join("library"))
}

/// Load a primary config file plus all of its transitive imports and merge them.
///
/// Invariants enforced:
/// * Profile names must be unique across the entire merged bundle (hard error).
/// * Import cycles are detected and reported.
/// * Only the primary file's `post_prompt` is kept; imports' are ignored.
///
/// `primary_default_library` is the library root to use for the primary
/// config when it does not declare `library = "..."`. Pass
/// `Some(~/.local/prompter/library)` when loading the default config, or
/// `None` when the user supplied `-c FILE` (in which case the primary falls
/// back to `<FILE-dir>/library`).
///
/// # Errors
/// Returns an error on I/O failure, TOML parse failure, unresolved import
/// paths, import cycles, or duplicate profile names.
pub fn load_config_bundle(
    primary_path: &Path,
    primary_default_library: Option<&Path>,
) -> Result<Config, PrompterError> {
    let mut profiles: HashMap<String, ProfileDef> = HashMap::new();
    let mut visited: HashSet<PathBuf> = HashSet::new();
    let mut post_prompt: Option<String> = None;

    load_one(
        primary_path,
        primary_default_library,
        true,
        &mut profiles,
        &mut visited,
        &mut post_prompt,
    )?;

    Ok(Config {
        profiles,
        post_prompt,
    })
}

fn load_one(
    path: &Path,
    default_library: Option<&Path>,
    is_primary: bool,
    profiles: &mut HashMap<String, ProfileDef>,
    visited: &mut HashSet<PathBuf>,
    post_prompt: &mut Option<String>,
) -> Result<(), PrompterError> {
    let text = read_config_with_path(path)?;
    let canonical = fs::canonicalize(path).map_err(|source| PrompterError::Io {
        path: path.to_path_buf(),
        source,
    })?;

    if !visited.insert(canonical.clone()) {
        return Err(PrompterError::ImportCycle(canonical));
    }

    let raw = parse_config_file(&text)?;

    let library_root = library_root_for(&canonical, raw.library.as_deref(), default_library)?;

    for (name, deps) in raw.profiles {
        if let Some(existing) = profiles.get(&name) {
            return Err(PrompterError::DuplicateProfile(format!(
                "Duplicate profile `{}` defined in both {} and {}",
                name,
                existing.library_root.display(),
                library_root.display()
            )));
        }
        profiles.insert(
            name,
            ProfileDef {
                deps,
                library_root: library_root.clone(),
            },
        );
    }

    if is_primary {
        *post_prompt = raw.post_prompt.map(|s| unescape(&s));
    }

    let importer_dir = canonical
        .parent()
        .ok_or_else(|| PrompterError::NoParentDir(canonical.clone()))?
        .to_path_buf();
    for import_str in raw.imports {
        let import_path = resolve_import_path(&importer_dir, &import_str)?;
        // Imported configs never use the primary default library; they always
        // resolve their library via `library = "..."` or `<their-dir>/library`.
        load_one(&import_path, None, false, profiles, visited, post_prompt)?;
    }

    Ok(())
}

/// Errors that can occur during profile resolution.
///
/// These errors represent various failure modes when resolving
/// profile dependencies and validating file references.
#[derive(thiserror::Error, Debug, PartialEq, Eq)]
pub enum ResolveError {
    /// Referenced profile name does not exist in configuration
    #[error("Unknown profile: {0}")]
    UnknownProfile(String),
    /// Circular dependency detected in profile references
    #[error("Cycle detected: {}", .0.join(" -> "))]
    Cycle(Vec<String>),
    /// Referenced markdown file does not exist
    #[error("Missing file: {path} (referenced by [{referenced_by}])", path = .0.display(), referenced_by = .1)]
    MissingFile(PathBuf, String), // (path, referenced_by)
}

/// Node type in the dependency tree
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
#[serde(rename_all = "lowercase")]
pub enum TreeNodeType {
    /// Profile node
    Profile,
    /// Fragment (markdown file) node
    Fragment,
}

/// Tree node representing a profile or fragment in the dependency tree
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct TreeNode {
    /// Type of node (profile or fragment)
    #[serde(rename = "type")]
    pub node_type: TreeNodeType,
    /// Name of profile or path of fragment
    pub name: String,
    /// Children of this node
    #[serde(skip_serializing_if = "Vec::is_empty")]
    pub children: Vec<TreeNode>,
}

/// Complete tree structure for JSON output
#[derive(Debug, Serialize, Deserialize)]
pub struct TreeOutput {
    /// List of root trees (top-level profiles)
    pub trees: Vec<TreeNode>,
}

/// Recursively resolve a profile's dependencies into a list of
/// `(fragment_path, owning_library_root)` pairs.
///
/// Each `.md` dep is resolved against the owning profile's `library_root`,
/// so profiles imported from different bundles still find their fragments.
/// Profile-to-profile refs are looked up by name in the merged map.
///
/// Cycle detection and fragment deduplication (by absolute path) are
/// performed across the full traversal.
///
/// # Errors
/// Returns an error if:
/// - Profile name is not found in configuration
/// - Circular dependency is detected
/// - Referenced markdown file does not exist
#[allow(
    clippy::implicit_hasher,
    reason = "public resolver API intentionally fixes the std default HashMap hasher rather than exposing a hasher type parameter"
)]
pub fn resolve_profile(
    name: &str,
    cfg: &Config,
    seen_files: &mut HashSet<PathBuf>,
    stack: &mut Vec<String>,
    out: &mut Vec<(PathBuf, PathBuf)>,
) -> Result<(), ResolveError> {
    if stack.contains(&name.to_string()) {
        let mut cycle = stack.clone();
        cycle.push(name.to_string());
        return Err(ResolveError::Cycle(cycle));
    }
    let profile = cfg
        .profiles
        .get(name)
        .ok_or_else(|| ResolveError::UnknownProfile(name.to_string()))?;
    stack.push(name.to_string());
    for dep in &profile.deps {
        if std::path::Path::new(dep)
            .extension()
            .is_some_and(|ext| ext.eq_ignore_ascii_case("md"))
        {
            let path = profile.library_root.join(dep);
            if !path.exists() {
                return Err(ResolveError::MissingFile(path, name.to_string()));
            }
            if seen_files.insert(path.clone()) {
                out.push((path, profile.library_root.clone()));
            }
        } else {
            resolve_profile(dep, cfg, seen_files, stack, out)?;
        }
    }
    stack.pop();
    Ok(())
}

/// JSON output structure for list command.
#[derive(Debug, Serialize)]
struct ListOutput {
    profiles: Vec<ProfileInfo>,
    libraries: Vec<LibraryOutput>,
}

/// Profile information for JSON output.
#[derive(Debug, Serialize)]
struct ProfileInfo {
    name: String,
    dependencies: Vec<String>,
    library_root: String,
}

/// One library directory plus the fragment paths it contains.
#[derive(Debug, Serialize)]
struct LibraryOutput {
    path: String,
    fragments: Vec<String>,
}

/// List all available profiles to a writer.
///
/// Text mode: one profile name per line, sorted alphabetically.
///
/// JSON mode: emits profiles (each tagged with the library root it was loaded
/// against) plus a `libraries` array, one entry per unique library root seen
/// across the merged bundle.
///
/// # Errors
/// Returns an error if writing to the output fails or a library directory
/// cannot be read.
pub fn list_profiles(
    cfg: &Config,
    output: JsonOutput,
    mut w: impl Write,
) -> Result<(), PrompterError> {
    if output.is_json() {
        // Gather unique library roots from all loaded profiles.
        let mut unique_roots: Vec<PathBuf> = Vec::new();
        for profile in cfg.profiles.values() {
            if !unique_roots.contains(&profile.library_root) {
                unique_roots.push(profile.library_root.clone());
            }
        }
        unique_roots.sort();

        let mut libraries = Vec::with_capacity(unique_roots.len());
        for root in &unique_roots {
            let mut fragments = Vec::new();
            if root.exists() {
                collect_fragments(root, root, &mut fragments)?;
            }
            fragments.sort();
            libraries.push(LibraryOutput {
                path: root.display().to_string(),
                fragments,
            });
        }

        let mut profiles: Vec<ProfileInfo> = cfg
            .profiles
            .iter()
            .map(|(name, def)| ProfileInfo {
                name: name.clone(),
                dependencies: def.deps.clone(),
                library_root: def.library_root.display().to_string(),
            })
            .collect();
        profiles.sort_by(|a, b| a.name.cmp(&b.name));

        let data = serde_json::to_value(ListOutput {
            profiles,
            libraries,
        })?;
        writeln!(
            &mut w,
            "{}",
            render_response("list", JsonOutput::Json, data, String::new())
        )
        .map_err(PrompterError::Write)?;
    } else {
        let mut names: Vec<_> = cfg.profiles.keys().cloned().collect();
        names.sort();
        for n in names {
            writeln!(&mut w, "{n}").map_err(PrompterError::Write)?;
        }
    }
    Ok(())
}

/// Recursively collect all .md files from a directory
fn collect_fragments(
    root: &Path,
    dir: &Path,
    fragments: &mut Vec<String>,
) -> Result<(), PrompterError> {
    let entries = fs::read_dir(dir).map_err(|source| PrompterError::Io {
        path: dir.to_path_buf(),
        source,
    })?;

    for entry in entries {
        let entry = entry.map_err(|source| PrompterError::Io {
            path: dir.to_path_buf(),
            source,
        })?;
        let path = entry.path();

        if path.is_dir() {
            collect_fragments(root, &path, fragments)?;
        } else if path
            .extension()
            .is_some_and(|ext| ext.eq_ignore_ascii_case("md"))
        {
            if let Ok(rel_path) = path.strip_prefix(root) {
                fragments.push(rel_path.display().to_string());
            }
        }
    }

    Ok(())
}

/// Validate configuration and library file references.
///
/// Checks that all profile dependencies are valid, including:
/// - Referenced profiles exist in configuration
/// - Referenced markdown files exist in their owning library root
/// - No circular dependencies exist
///
/// # Errors
/// Returns an error if:
/// - Referenced profiles don't exist
/// - Referenced files don't exist
/// - Circular dependencies are detected
pub fn validate(cfg: &Config) -> Result<(), PrompterError> {
    let mut errors: Vec<String> = Vec::new();

    for (profile_name, profile) in &cfg.profiles {
        for dep in &profile.deps {
            if std::path::Path::new(dep)
                .extension()
                .is_some_and(|ext| ext.eq_ignore_ascii_case("md"))
            {
                let path = profile.library_root.join(dep);
                if !path.exists() {
                    errors.push(format!(
                        "Missing file: {} (referenced by [{}])",
                        path.display(),
                        profile_name
                    ));
                }
            } else if !cfg.profiles.contains_key(dep) {
                errors.push(format!(
                    "Unknown profile: {dep} (referenced by [{profile_name}])"
                ));
            }
        }
    }

    for name in cfg.profiles.keys() {
        let mut seen_files = HashSet::new();
        let mut stack = Vec::new();
        let mut out = Vec::new();
        if let Err(ResolveError::Cycle(cycle)) =
            resolve_profile(name, cfg, &mut seen_files, &mut stack, &mut out)
        {
            let chain = cycle.join(" -> ");
            errors.push(format!("Cycle detected: {chain}"));
        }
    }

    if errors.is_empty() {
        Ok(())
    } else {
        Err(PrompterError::Validation(errors.join("\n")))
    }
}

/// Build a tree node for a profile or fragment
fn build_tree_node(name: &str, cfg: &Config) -> TreeNode {
    // Check if it's a fragment (ends with .md)
    if std::path::Path::new(name)
        .extension()
        .is_some_and(|ext| ext.eq_ignore_ascii_case("md"))
    {
        return TreeNode {
            node_type: TreeNodeType::Fragment,
            name: name.to_string(),
            children: Vec::new(),
        };
    }

    // It's a profile - recursively build children
    let children = cfg
        .profiles
        .get(name)
        .map(|def| {
            def.deps
                .iter()
                .map(|dep| build_tree_node(dep, cfg))
                .collect()
        })
        .unwrap_or_default();

    TreeNode {
        node_type: TreeNodeType::Profile,
        name: name.to_string(),
        children,
    }
}

/// Find root profiles (profiles that are not referenced by any other profile)
fn find_root_profiles(cfg: &Config) -> Vec<String> {
    let mut referenced = HashSet::new();

    // Collect all profiles that are referenced by others
    for profile in cfg.profiles.values() {
        for dep in &profile.deps {
            // Only track profile references (not .md files)
            if !std::path::Path::new(dep)
                .extension()
                .is_some_and(|ext| ext.eq_ignore_ascii_case("md"))
            {
                referenced.insert(dep.clone());
            }
        }
    }

    // Find profiles that are never referenced
    let mut roots: Vec<String> = cfg
        .profiles
        .keys()
        .filter(|profile| !referenced.contains(*profile))
        .cloned()
        .collect();

    roots.sort();
    roots
}

/// Build complete tree structure for all root profiles
fn build_trees(cfg: &Config) -> TreeOutput {
    let root_profiles = find_root_profiles(cfg);
    let trees = root_profiles
        .iter()
        .map(|profile| build_tree_node(profile, cfg))
        .collect();

    TreeOutput { trees }
}

/// Print tree structure in traditional tree format
fn print_tree(node: &TreeNode, prefix: &str, is_last: bool, w: &mut impl Write) -> io::Result<()> {
    // Print current node with appropriate connector
    let connector = if is_last { "└── " } else { "├── " };
    writeln!(w, "{prefix}{connector}{}", node.name)?;

    // Prepare prefix for children
    let child_prefix = format!("{}{}", prefix, if is_last { "    " } else { "│   " });

    // Print children
    for (i, child) in node.children.iter().enumerate() {
        let is_last_child = i == node.children.len() - 1;
        print_tree(child, &child_prefix, is_last_child, w)?;
    }

    Ok(())
}

/// Show tree structure for all profiles
pub fn show_tree(cfg: &Config, output: JsonOutput, mut w: impl Write) -> Result<(), PrompterError> {
    let trees = build_trees(cfg);

    if output.is_json() {
        let data = serde_json::to_value(&trees)?;
        writeln!(
            &mut w,
            "{}",
            render_response("tree", JsonOutput::Json, data, String::new())
        )
        .map_err(PrompterError::Write)?;
    } else {
        for (i, tree) in trees.trees.iter().enumerate() {
            // Print root profile name
            writeln!(&mut w, "{}", tree.name).map_err(PrompterError::Write)?;

            // Print children with tree structure
            for (j, child) in tree.children.iter().enumerate() {
                let is_last = j == tree.children.len() - 1;
                print_tree(child, "", is_last, &mut w).map_err(PrompterError::Write)?;
            }

            // Add blank line between trees (except after last one)
            if i < trees.trees.len() - 1 {
                writeln!(&mut w).map_err(PrompterError::Write)?;
            }
        }
    }

    Ok(())
}

/// Show tree structure to stdout
pub fn run_tree_stdout(
    config_override: Option<&Path>,
    output: JsonOutput,
) -> Result<(), PrompterError> {
    let (_cfg_path, cfg) = load_bundle(config_override)?;
    show_tree(&cfg, output, io::stdout())
}