ryo-symbol 0.1.0

//! Workspace path resolver for normalizing and validating paths

use std::path::{Component, Path, PathBuf};
use std::sync::Arc;

use crate::crate_name::CrateName;
use crate::error::ResolveError;
use crate::file_path::WorkspaceFilePath;
use crate::metadata::WorkspaceMetadataProvider;
use crate::path::SymbolPath;
use crate::symbol_resolver::SymbolPathResolver;

/// Entry point type for a crate
///
/// Determines whether the crate root is `lib.rs` or `main.rs`.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
pub enum EntryPoint {
    /// Library crate: `src/lib.rs`
    #[default]
    Lib,
    /// Binary crate: `src/main.rs`
    Bin,
}

impl EntryPoint {
    /// Get the file name for this entry point
    pub fn file_name(&self) -> &'static str {
        match self {
            Self::Lib => "lib.rs",
            Self::Bin => "main.rs",
        }
    }

    /// Infer entry point from a file path
    ///
    /// Checks if the path ends with `main.rs` or `lib.rs`.
    pub fn from_path(path: &std::path::Path) -> Self {
        if let Some(file_name) = path.file_name().and_then(|n| n.to_str()) {
            if file_name == "main.rs" {
                return Self::Bin;
            }
        }
        Self::Lib
    }
}

/// Type of workspace structure
///
/// Determined by `[workspace]` section in Cargo.toml:
/// - `Workspace`: Has `[workspace]` section (multi-crate or single-crate in subdirectory)
/// - `Crate`: No `[workspace]` section (single crate at root)
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
pub enum WorkspaceType {
    /// Multi-crate workspace or single crate in subdirectory
    /// File layout: `crates/{crate}/src/*.rs` or `{crate}/src/*.rs`
    #[default]
    Workspace,
    /// Single crate at workspace root
    /// File layout: `src/*.rs`
    Crate,
}

/// Layout of a crate within a workspace
///
/// Determines the file path prefix for a crate's source files.
/// Used by `SymbolPathResolver` to convert `SymbolPath` → `WorkspaceFilePath`.
///
/// # Examples
///
/// ```ignore
/// // Single crate at workspace root: src/lib.rs
/// CrateLayout::Root
///
/// // Standard workspace: crates/my-crate/src/lib.rs
/// CrateLayout::InCrates { crate_dir_name: "my-crate".to_string() }
///
/// // Custom path: packages/core/src/lib.rs
/// CrateLayout::Custom { prefix: PathBuf::from("packages/core") }
/// ```
#[derive(Debug, Clone, PartialEq, Eq, Default)]
pub enum CrateLayout {
    /// Crate at workspace root: `src/*.rs`
    #[default]
    Root,
    /// Crate in `crates/` directory: `crates/{crate_dir_name}/src/*.rs`
    InCrates {
        /// Directory name (may differ from crate name due to hyphens)
        crate_dir_name: String,
    },
    /// Crate at custom path: `{prefix}/src/*.rs`
    Custom {
        /// Path prefix relative to workspace root
        prefix: PathBuf,
    },
}

impl CrateLayout {
    /// Create layout for a crate in `crates/` directory
    pub fn in_crates(crate_dir_name: impl Into<String>) -> Self {
        Self::InCrates {
            crate_dir_name: crate_dir_name.into(),
        }
    }

    /// Create layout for a crate at custom path
    pub fn custom(prefix: impl Into<PathBuf>) -> Self {
        Self::Custom {
            prefix: prefix.into(),
        }
    }

    /// Get the source directory path relative to workspace root
    ///
    /// Returns the path to the `src/` directory for this crate.
    pub fn src_dir(&self) -> PathBuf {
        match self {
            Self::Root => PathBuf::from("src"),
            Self::InCrates { crate_dir_name } => {
                PathBuf::from(format!("crates/{}/src", crate_dir_name))
            }
            Self::Custom { prefix } => prefix.join("src"),
        }
    }

    /// Convert a crate-relative path to a workspace-relative path.
    ///
    /// This is essential for converting generator output paths (e.g., `"src/lib.rs"`)
    /// to workspace-relative paths (e.g., `"crates/my-crate/src/lib.rs"`).
    ///
    /// # Arguments
    ///
    /// * `crate_relative` - Path relative to crate root (e.g., `"src/lib.rs"`, `"src/foo/bar.rs"`)
    ///
    /// # Returns
    ///
    /// Path relative to workspace root.
    ///
    /// # Examples
    ///
    /// ```
    /// use ryo_symbol::CrateLayout;
    /// use std::path::PathBuf;
    ///
    /// // Root layout: path unchanged
    /// let root = CrateLayout::Root;
    /// assert_eq!(root.to_workspace_relative("src/lib.rs"), PathBuf::from("src/lib.rs"));
    ///
    /// // InCrates layout: prepend crates/{name}/
    /// let in_crates = CrateLayout::in_crates("my-crate");
    /// assert_eq!(
    ///     in_crates.to_workspace_relative("src/lib.rs"),
    ///     PathBuf::from("crates/my-crate/src/lib.rs")
    /// );
    ///
    /// // Custom layout: prepend custom prefix
    /// let custom = CrateLayout::custom("packages/core");
    /// assert_eq!(
    ///     custom.to_workspace_relative("src/lib.rs"),
    ///     PathBuf::from("packages/core/src/lib.rs")
    /// );
    /// ```
    pub fn to_workspace_relative(&self, crate_relative: impl AsRef<Path>) -> PathBuf {
        let crate_relative = crate_relative.as_ref();

        match self {
            Self::Root => {
                // Root layout: path is already workspace-relative
                crate_relative.to_path_buf()
            }
            Self::InCrates { crate_dir_name } => {
                // InCrates: prepend "crates/{name}/"
                PathBuf::from(format!("crates/{}", crate_dir_name)).join(crate_relative)
            }
            Self::Custom { prefix } => {
                // Custom: prepend the custom prefix
                prefix.join(crate_relative)
            }
        }
    }

    /// Infer layout from a WorkspaceFilePath
    ///
    /// Analyzes the path structure to determine the crate layout.
    pub fn from_workspace_file_path(path: &WorkspaceFilePath) -> Self {
        let path_str = path.as_relative().to_string_lossy();

        // Check for crates/{name}/src/ pattern
        if let Some(idx) = path_str.find("crates/") {
            let after_crates = &path_str[idx + 7..];
            if let Some(end_idx) = after_crates.find('/') {
                let crate_dir_name = &after_crates[..end_idx];
                return Self::InCrates {
                    crate_dir_name: crate_dir_name.to_string(),
                };
            }
        }

        // Check for direct src/ (root layout)
        if path_str.starts_with("src/") {
            return Self::Root;
        }

        // Check for custom prefix (anything before /src/)
        if let Some(idx) = path_str.find("/src/") {
            let prefix = &path_str[..idx];
            return Self::Custom {
                prefix: PathBuf::from(prefix),
            };
        }

        // Default to root
        Self::Root
    }
}

/// Workspace path resolver
///
/// Normalizes and validates paths relative to a workspace root.
/// This is the **only** way to create `WorkspaceFilePath` instances.
///
/// # Responsibilities
/// - Convert any path (absolute/relative) to `WorkspaceFilePath`
/// - Normalize paths (resolve `..` and `.`)
/// - Validate paths are within workspace
/// - Share workspace_root via `Arc<Path>` for efficient cloning
///
/// # Example
/// ```ignore
/// let resolver = WorkspacePathResolver::new("/home/user/project".into());
///
/// // Absolute path
/// let p1 = resolver.resolve("/home/user/project/src/lib.rs")?;
///
/// // Relative path (resolved from CWD)
/// let p2 = resolver.resolve("./src/../src/lib.rs")?;
///
/// // Strict mode (also checks file existence)
/// let p3 = resolver.resolve_strict("src/lib.rs")?;
/// ```
#[derive(Debug, Clone)]
pub struct WorkspacePathResolver {
    workspace_root: Arc<Path>,
    workspace_type: WorkspaceType,
}

impl WorkspacePathResolver {
    /// Create a new resolver with the given workspace root
    ///
    /// Defaults to `WorkspaceType::Workspace`. Use `with_type` for explicit control.
    pub fn new(workspace_root: PathBuf) -> Self {
        Self {
            workspace_root: Arc::from(workspace_root),
            workspace_type: WorkspaceType::default(),
        }
    }

    /// Create a new resolver with explicit workspace type
    pub fn with_type(workspace_root: PathBuf, workspace_type: WorkspaceType) -> Self {
        Self {
            workspace_root: Arc::from(workspace_root),
            workspace_type,
        }
    }

    /// Get the workspace type
    pub fn workspace_type(&self) -> WorkspaceType {
        self.workspace_type
    }

    /// Resolve any path to a WorkspaceFilePath with provider-based crate resolution
    ///
    /// - Absolute path → convert to relative from workspace_root
    /// - Relative path → resolve from CWD, then convert
    /// - `..` / `.` → resolved
    /// - Outside workspace → error
    /// - crate_name → resolved from provider
    pub fn resolve_with_provider<P: WorkspaceMetadataProvider>(
        &self,
        path: impl AsRef<Path>,
        provider: &P,
    ) -> Result<WorkspaceFilePath, ResolveError> {
        let path = path.as_ref();

        // 1. Convert to absolute path
        let absolute = if path.is_absolute() {
            path.to_path_buf()
        } else {
            std::env::current_dir()?.join(path)
        };

        // 2. Normalize (resolve .. and ., no I/O)
        let normalized = normalize_path(&absolute);

        // 3. Convert to relative path from workspace_root
        let relative = normalized
            .strip_prefix(&*self.workspace_root)
            .map_err(|_| ResolveError::OutsideWorkspace {
                path: normalized.clone(),
                workspace: self.workspace_root.to_path_buf(),
            })?
            .to_path_buf();

        // 4. Create temporary path to resolve crate name
        // We need to create a temporary WorkspaceFilePath to pass to the provider
        // Use a placeholder crate name first, then resolve the real one
        let temp_crate = CrateName::new_unchecked("__temp__");
        let temp_path = WorkspaceFilePath::new_unchecked(
            relative.clone(),
            Arc::clone(&self.workspace_root),
            temp_crate,
        );

        // 5. Resolve crate name from provider
        let crate_name = provider
            .crate_for_file(&temp_path)
            .ok_or_else(|| ResolveError::CrateNotFound(normalized.clone()))?;

        Ok(WorkspaceFilePath::new_unchecked(
            relative,
            Arc::clone(&self.workspace_root),
            crate_name,
        ))
    }

    /// Resolve with file existence check (strict mode)
    pub fn resolve_strict_with_provider<P: WorkspaceMetadataProvider>(
        &self,
        path: impl AsRef<Path>,
        provider: &P,
    ) -> Result<WorkspaceFilePath, ResolveError> {
        let workspace_path = self.resolve_with_provider(path, provider)?;
        let absolute = workspace_path.to_absolute();

        if !absolute.exists() {
            return Err(ResolveError::FileNotFound(absolute));
        }

        Ok(workspace_path)
    }

    /// Resolve from a path that's already relative to workspace root (with explicit crate name)
    ///
    /// This skips CWD resolution and directly creates a WorkspaceFilePath.
    /// Useful when you already have a known-good relative path and crate name.
    pub fn resolve_relative_with_crate(
        &self,
        relative: impl AsRef<Path>,
        crate_name: CrateName,
    ) -> WorkspaceFilePath {
        let relative = relative.as_ref();
        let normalized = normalize_path(relative);
        WorkspaceFilePath::new_unchecked(normalized, Arc::clone(&self.workspace_root), crate_name)
    }

    /// Resolve from a path that's already relative to workspace root (with provider)
    ///
    /// This skips CWD resolution and uses the provider to resolve the crate name.
    pub fn resolve_relative_with_provider<P: WorkspaceMetadataProvider>(
        &self,
        relative: impl AsRef<Path>,
        provider: &P,
    ) -> Option<WorkspaceFilePath> {
        let relative = relative.as_ref();
        let normalized = normalize_path(relative);

        // Create temporary path to resolve crate name
        let temp_crate = CrateName::new_unchecked("__temp__");
        let temp_path = WorkspaceFilePath::new_unchecked(
            normalized.clone(),
            Arc::clone(&self.workspace_root),
            temp_crate,
        );

        // Resolve crate name from provider
        let crate_name = provider.crate_for_file(&temp_path)?;

        Some(WorkspaceFilePath::new_unchecked(
            normalized,
            Arc::clone(&self.workspace_root),
            crate_name,
        ))
    }

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

    /// Get the workspace root as Arc (for deserialization)
    pub fn workspace_root_arc(&self) -> Arc<Path> {
        Arc::clone(&self.workspace_root)
    }

    // ========== Module to File Resolution ==========

    /// Resolve module path to file path
    ///
    /// This method centralizes the logic for determining which file a module belongs to.
    /// It handles the distinction between:
    /// - **Crate root (depth 1)**: span points to the actual file (main.rs/lib.rs)
    /// - **Sub-modules (depth > 1)**: span points to declaration site (`mod foo;` in lib.rs),
    ///   so path-based inference is needed to get the actual file (foo.rs)
    ///
    /// # Arguments
    ///
    /// - `module_path`: The symbol path of the module
    /// - `crate_name`: The crate name for path inference
    /// - `span_file`: Optional span file (use for crate root to preserve main.rs vs lib.rs)
    ///
    /// # Example
    ///
    /// ```ignore
    /// let resolver = WorkspacePathResolver::new("/workspace".into());
    ///
    /// // For crate root with span → uses span file (preserves main.rs)
    /// let file = resolver.module_to_file(&module_path, &crate_name, Some(&span_file));
    ///
    /// // For sub-module → uses path-based inference
    /// let file = resolver.module_to_file(&module_path, &crate_name, None);
    /// ```
    pub fn module_to_file(
        &self,
        module_path: &SymbolPath,
        crate_name: &CrateName,
        span_file: Option<&WorkspaceFilePath>,
    ) -> WorkspaceFilePath {
        // Crate root (depth 1): span points to actual file (main.rs/lib.rs)
        if module_path.depth() == 1 {
            if let Some(span_file) = span_file {
                return span_file.clone();
            }
        }

        // Sub-module or no span: use path-based inference
        let symbol_resolver = SymbolPathResolver::from_crate_name(crate_name.clone());

        // Create a virtual child to get the containing file
        // (e.g., crate::storage → crate::storage::_ → src/storage.rs)
        if let Ok(virtual_child) = module_path.child("_") {
            symbol_resolver.to_workspace_file_path(&virtual_child, self.workspace_root_arc())
        } else {
            symbol_resolver.to_workspace_file_path(module_path, self.workspace_root_arc())
        }
    }

    // ========== Simplified API (infers crate_name from path) ==========

    /// Resolve any path to a WorkspaceFilePath (infers crate_name from path)
    ///
    /// This is a simplified API that attempts to infer the crate name from the path.
    /// It looks for `crates/<crate-name>/` in the path structure.
    ///
    /// For more control, use `resolve_with_provider` or `resolve_relative_with_crate`.
    pub fn resolve(&self, path: impl AsRef<Path>) -> Result<WorkspaceFilePath, ResolveError> {
        let path = path.as_ref();

        // 1. Convert to absolute path
        let absolute = if path.is_absolute() {
            path.to_path_buf()
        } else {
            std::env::current_dir()?.join(path)
        };

        // 2. Normalize (resolve .. and ., no I/O)
        let normalized = normalize_path(&absolute);

        // 3. Convert to relative path from workspace_root
        let relative = normalized
            .strip_prefix(&*self.workspace_root)
            .map_err(|_| ResolveError::OutsideWorkspace {
                path: normalized.clone(),
                workspace: self.workspace_root.to_path_buf(),
            })?
            .to_path_buf();

        // 4. Infer crate name from path
        let crate_name = infer_crate_name(&relative);

        Ok(WorkspaceFilePath::new_unchecked(
            relative,
            Arc::clone(&self.workspace_root),
            crate_name,
        ))
    }

    /// Resolve from a path that's already relative to workspace root (infers crate_name)
    ///
    /// This is a simplified API that skips CWD resolution and infers the crate name.
    pub fn resolve_relative(&self, relative: impl AsRef<Path>) -> Option<WorkspaceFilePath> {
        let relative = relative.as_ref();
        let normalized = normalize_path(relative);
        let crate_name = infer_crate_name(&normalized);

        Some(WorkspaceFilePath::new_unchecked(
            normalized,
            Arc::clone(&self.workspace_root),
            crate_name,
        ))
    }

    // ========== Validation API ==========

    /// Validate that a `crate::` prefixed path is unambiguous in this workspace
    ///
    /// In a multi-crate workspace (`WorkspaceType::Workspace`), paths starting with
    /// `crate::` are ambiguous because it's unclear which crate is being referred to.
    ///
    /// # Arguments
    ///
    /// - `path`: The path string to validate (e.g., "crate::domain::model")
    /// - `workspace_members`: List of workspace member paths for error message (e.g., ["crates/core", "crates/api"])
    ///
    /// # Returns
    ///
    /// - `Ok(())` if the path is unambiguous (single crate or doesn't start with `crate::`)
    /// - `Err(ResolveError::AmbiguousCratePath)` if ambiguous in multi-crate workspace
    ///
    /// # Example
    ///
    /// ```ignore
    /// let resolver = WorkspacePathResolver::with_type(root, WorkspaceType::Workspace);
    /// let members = vec!["crates/core".to_string(), "crates/api".to_string()];
    ///
    /// // This will error in multi-crate workspace
    /// resolver.validate_crate_path("crate::domain", &members)?;
    ///
    /// // These are OK
    /// resolver.validate_crate_path("core::domain", &members)?;  // explicit crate name
    /// resolver.validate_crate_path("src/domain.rs", &members)?; // file path
    /// ```
    pub fn validate_crate_path(
        &self,
        path: &str,
        workspace_members: &[String],
    ) -> Result<(), ResolveError> {
        // Only validate for multi-crate workspaces
        if self.workspace_type != WorkspaceType::Workspace {
            return Ok(());
        }

        // Only validate paths starting with "crate::"
        if !path.starts_with("crate::") {
            return Ok(());
        }

        // Single-member workspace is not ambiguous
        if workspace_members.len() <= 1 {
            return Ok(());
        }

        // Multi-crate workspace with crate:: path is ambiguous
        let first_member = workspace_members.first().cloned().unwrap_or_default();
        let crate_name = first_member
            .split('/')
            .next_back()
            .unwrap_or(&first_member)
            .to_string();

        // Extract module path from "crate::xxx" -> "xxx"
        let module_suffix = path.strip_prefix("crate::").unwrap_or("");
        let example_file_path = if module_suffix.is_empty() {
            format!("{}/src/lib.rs", first_member)
        } else {
            format!(
                "{}/src/{}.rs",
                first_member,
                module_suffix.replace("::", "/")
            )
        };

        Err(ResolveError::AmbiguousCratePath {
            path: path.to_string(),
            example_crate_path: first_member,
            example_file_path,
            example_crate_name: crate_name,
        })
    }
}

/// Infer crate name from a relative path
///
/// Looks for `crates/<crate-name>/` pattern in the path.
/// Falls back to "crate" if pattern not found.
fn infer_crate_name(path: &Path) -> CrateName {
    let path_str = path.to_string_lossy();

    // Look for "crates/<name>/" pattern
    if let Some(idx) = path_str.find("crates/") {
        let after_crates = &path_str[idx + 7..];
        if let Some(end_idx) = after_crates.find('/') {
            let crate_name = &after_crates[..end_idx];
            return CrateName::new_unchecked(crate_name);
        }
    }

    // Fallback: use first component if it looks like a crate (has src/)
    if path_str.contains("/src/") || path_str.starts_with("src/") {
        // Path is already in crate root, use "crate" as default
        return CrateName::new_unchecked("crate");
    }

    // Default fallback
    CrateName::new_unchecked("crate")
}

/// Normalize a path without I/O (resolve `..` and `.`)
///
/// # Precondition
/// For best results, input should be an absolute path.
/// Relative paths with `..` that exceed the root will have those
/// components silently dropped.
fn normalize_path(path: &Path) -> PathBuf {
    let mut components = Vec::new();

    for comp in path.components() {
        match comp {
            Component::ParentDir => {
                // `/foo/..` → `/`
                // Don't pop RootDir or Prefix (Windows)
                if let Some(Component::Normal(_)) = components.last() {
                    components.pop();
                }
            }
            Component::CurDir => {
                // `.` is skipped
            }
            c => components.push(c),
        }
    }

    components.iter().collect()
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_normalize_path() {
        assert_eq!(
            normalize_path(Path::new("/foo/bar/../baz")),
            PathBuf::from("/foo/baz")
        );
        assert_eq!(
            normalize_path(Path::new("/foo/./bar")),
            PathBuf::from("/foo/bar")
        );
        assert_eq!(
            normalize_path(Path::new("/foo/bar/../../baz")),
            PathBuf::from("/baz")
        );
        assert_eq!(
            normalize_path(Path::new("foo/bar/../baz")),
            PathBuf::from("foo/baz")
        );
    }

    #[test]
    fn test_resolve_relative_with_crate() {
        let resolver = WorkspacePathResolver::new(PathBuf::from("/workspace"));
        let crate_name = CrateName::new_for_test("my_crate");

        let path = resolver.resolve_relative_with_crate("src/lib.rs", crate_name);
        assert_eq!(path.as_relative(), Path::new("src/lib.rs"));
        assert_eq!(path.workspace_root(), Path::new("/workspace"));
        assert_eq!(path.crate_name().as_str(), "my_crate");
    }

    #[test]
    fn test_resolve_relative_with_dots_and_crate() {
        let resolver = WorkspacePathResolver::new(PathBuf::from("/workspace"));
        let crate_name = CrateName::new_for_test("my_crate");

        let path = resolver.resolve_relative_with_crate("src/../src/./lib.rs", crate_name);
        assert_eq!(path.as_relative(), Path::new("src/lib.rs"));
        assert_eq!(path.crate_name().as_str(), "my_crate");
    }

    #[test]
    fn test_resolve_relative_with_provider() {
        use crate::metadata::MockMetadataProvider;

        let resolver = WorkspacePathResolver::new(PathBuf::from("/workspace"));
        let provider = MockMetadataProvider::new("/workspace", "test_crate");

        let path = resolver
            .resolve_relative_with_provider("src/lib.rs", &provider)
            .unwrap();
        assert_eq!(path.as_relative(), Path::new("src/lib.rs"));
        assert_eq!(path.crate_name().as_str(), "test_crate");
    }

    // ========================================================================
    // CrateLayout::to_workspace_relative tests
    // ========================================================================

    #[test]
    fn test_crate_layout_to_workspace_relative_root() {
        // Root layout: src/lib.rs stays as src/lib.rs
        let layout = CrateLayout::Root;
        let result = layout.to_workspace_relative("src/lib.rs");
        assert_eq!(result, PathBuf::from("src/lib.rs"));
    }

    #[test]
    fn test_crate_layout_to_workspace_relative_in_crates() {
        // InCrates layout: src/lib.rs → crates/my-crate/src/lib.rs
        let layout = CrateLayout::in_crates("my-crate");
        let result = layout.to_workspace_relative("src/lib.rs");
        assert_eq!(result, PathBuf::from("crates/my-crate/src/lib.rs"));
    }

    #[test]
    fn test_crate_layout_to_workspace_relative_in_crates_nested() {
        // InCrates layout: src/foo/bar.rs → crates/my-crate/src/foo/bar.rs
        let layout = CrateLayout::in_crates("my-crate");
        let result = layout.to_workspace_relative("src/foo/bar.rs");
        assert_eq!(result, PathBuf::from("crates/my-crate/src/foo/bar.rs"));
    }

    #[test]
    fn test_crate_layout_to_workspace_relative_custom() {
        // Custom layout: src/lib.rs → packages/core/src/lib.rs
        let layout = CrateLayout::custom("packages/core");
        let result = layout.to_workspace_relative("src/lib.rs");
        assert_eq!(result, PathBuf::from("packages/core/src/lib.rs"));
    }

    #[test]
    fn test_crate_layout_to_workspace_relative_main_rs() {
        // Binary: src/main.rs → crates/my-cli/src/main.rs
        let layout = CrateLayout::in_crates("my-cli");
        let result = layout.to_workspace_relative("src/main.rs");
        assert_eq!(result, PathBuf::from("crates/my-cli/src/main.rs"));
    }
}