rustloclib 0.13.1

//! High-level LOC counting API.
//!
//! This module provides the main entry points for counting lines of code
//! in Rust projects, with support for workspace filtering and glob patterns.

use std::collections::HashMap;
use std::path::{Path, PathBuf};

use crate::error::RustlocError;
use crate::query::options::{Aggregation, LineTypes};
use crate::source::filter::{discover_files, discover_files_in_dirs, FilterConfig};
use crate::source::workspace::{CrateInfo, WorkspaceInfo};
use crate::Result;

use super::stats::{CrateStats, FileStats, Locs, ModuleStats};
use super::visitor::gather_stats_for_path;

/// Options for counting LOC.
#[derive(Debug, Clone)]
pub struct CountOptions {
    /// Filter by crate names (empty = all crates)
    pub crate_filter: Vec<String>,
    /// File filter configuration
    pub file_filter: FilterConfig,
    /// Aggregation level for results
    pub aggregation: Aggregation,
    /// Which line types to include in results
    pub line_types: LineTypes,
}

impl Default for CountOptions {
    fn default() -> Self {
        Self {
            crate_filter: Vec::new(),
            file_filter: FilterConfig::new(),
            aggregation: Aggregation::Total,
            line_types: LineTypes::default(),
        }
    }
}

impl CountOptions {
    /// Create new default options.
    pub fn new() -> Self {
        Self::default()
    }

    /// Filter to specific crates.
    pub fn crates(mut self, names: Vec<String>) -> Self {
        self.crate_filter = names;
        self
    }

    /// Set file filter.
    pub fn filter(mut self, filter: FilterConfig) -> Self {
        self.file_filter = filter;
        self
    }

    /// Set aggregation level.
    pub fn aggregation(mut self, level: Aggregation) -> Self {
        self.aggregation = level;
        self
    }

    /// Set which line types to include.
    pub fn line_types(mut self, types: LineTypes) -> Self {
        self.line_types = types;
        self
    }
}

/// Result of counting LOC in a workspace or directory.
#[derive(Debug, Clone, Default, serde::Serialize)]
pub struct CountResult {
    /// Root path of the workspace or directory analyzed
    pub root: PathBuf,
    /// Total number of files analyzed
    pub file_count: usize,
    /// Aggregated statistics across all files
    pub total: Locs,
    /// Per-crate statistics (if workspace)
    pub crates: Vec<CrateStats>,
    /// Per-file statistics (if requested)
    pub files: Vec<FileStats>,
    /// Per-module statistics (if requested)
    pub modules: Vec<ModuleStats>,
}

impl CountResult {
    /// Create a new empty result.
    pub fn new() -> Self {
        Self::default()
    }

    /// Return a filtered copy with only the specified line types included.
    pub fn filter(&self, types: LineTypes) -> Self {
        Self {
            root: self.root.clone(),
            file_count: self.file_count,
            total: self.total.filter(types),
            crates: self.crates.iter().map(|c| c.filter(types)).collect(),
            files: self.files.iter().map(|f| f.filter(types)).collect(),
            modules: self.modules.iter().map(|m| m.filter(types)).collect(),
        }
    }
}

/// Count LOC in a Cargo workspace.
///
/// This is the main entry point for analyzing a Rust project. It:
/// 1. Discovers the workspace structure
/// 2. Optionally filters to specific crates
/// 3. Applies glob filters to files
/// 4. Parses all matching files and aggregates statistics
///
/// # Example
///
/// ```rust
/// use rustloclib::{count_workspace, CountOptions, FilterConfig};
/// use std::fs;
/// use tempfile::tempdir;
///
/// let dir = tempdir().unwrap();
/// fs::write(dir.path().join("Cargo.toml"), r#"
/// [package]
/// name = "my-lib"
/// version = "0.1.0"
/// edition = "2021"
/// "#).unwrap();
/// fs::create_dir(dir.path().join("src")).unwrap();
/// fs::write(dir.path().join("src/lib.rs"), "pub fn hello() {}\n").unwrap();
///
/// // Count all crates in the workspace
/// let result = count_workspace(dir.path(), CountOptions::new()).unwrap();
/// assert_eq!(result.crates.len(), 0); // Total aggregation doesn't include crate breakdown
/// assert!(result.total.code >= 1);
///
/// // Exclude test files with filter
/// let filter = FilterConfig::new().exclude("**/tests/**").unwrap();
/// let result = count_workspace(dir.path(), CountOptions::new().filter(filter)).unwrap();
/// ```
pub fn count_workspace(path: impl AsRef<Path>, options: CountOptions) -> Result<CountResult> {
    let workspace = WorkspaceInfo::discover(path)?;

    // Filter crates if specified
    let crates: Vec<&CrateInfo> = if options.crate_filter.is_empty() {
        workspace.crates.iter().collect()
    } else {
        let names: Vec<&str> = options.crate_filter.iter().map(|s| s.as_str()).collect();
        workspace
            .crates
            .iter()
            .filter(|c| names.contains(&c.name.as_str()))
            .collect()
    };

    let mut result = CountResult::new();
    result.root = workspace.root.clone();

    // Determine what to include based on aggregation level
    let include_files = matches!(options.aggregation, Aggregation::ByFile);
    let include_modules = matches!(options.aggregation, Aggregation::ByModule);
    let include_crates = matches!(
        options.aggregation,
        Aggregation::ByCrate | Aggregation::ByModule | Aggregation::ByFile
    );

    for crate_info in &crates {
        let crate_stats = count_crate(crate_info, &options)?;
        result.total += crate_stats.stats;
        result.file_count += crate_stats.files.len();

        if include_files {
            result.files.extend(crate_stats.files.clone());
        }

        // Compute module stats per-crate if requested
        if include_modules {
            let crate_modules = aggregate_modules(&crate_stats.files, &crate_info.name, crate_info);
            result.modules.extend(crate_modules);
        }

        if include_crates {
            result.crates.push(crate_stats);
        }
    }

    // Sort modules by name for consistent output
    if include_modules {
        result.modules.sort_by(|a, b| a.name.cmp(&b.name));
    }

    // Apply line type filter
    Ok(result.filter(options.line_types))
}

/// Compute the module name for a file path relative to a source root.
///
/// Returns the directory-level module name so that all files within
/// a directory aggregate under a single module entry.
///
/// Module naming rules:
/// - `lib.rs`, `main.rs`, `mod.rs` in root → "" (root module)
/// - `foo.rs` in root → "foo"
/// - `foo/mod.rs` → "foo"
/// - `foo/bar.rs` → "foo" (aggregates with other files in foo/)
/// - `foo/sub/baz.rs` → "foo::sub"
/// - New-style: `foo.rs` + `foo/bar.rs` both → "foo"
pub fn compute_module_name(file_path: &Path, src_root: &Path) -> String {
    let relative = file_path.strip_prefix(src_root).unwrap_or(file_path);

    let mut components: Vec<&str> = relative
        .components()
        .filter_map(|c| c.as_os_str().to_str())
        .collect();

    if components.is_empty() {
        return String::new();
    }

    // Get the filename
    let filename = components.pop().unwrap_or("");
    let stem = filename.strip_suffix(".rs").unwrap_or(filename);

    // Special case: root module files
    if components.is_empty() && (stem == "lib" || stem == "main" || stem == "mod") {
        return String::new();
    }

    // mod.rs belongs to parent module
    if stem == "mod" {
        return components.join("::");
    }

    // Files inside a directory belong to that directory's module.
    // e.g., data/counter.rs → "data", data/sub/foo.rs → "data::sub"
    // Root-level files (like error.rs or data.rs) are their own module.
    // This means data.rs (new-style module entry) naturally aggregates
    // with files in data/ since both map to "data".
    if !components.is_empty() {
        components.join("::")
    } else {
        stem.to_string()
    }
}

/// Aggregate file stats into modules for a specific crate.
fn aggregate_modules(
    files: &[FileStats],
    crate_name: &str,
    crate_info: &CrateInfo,
) -> Vec<ModuleStats> {
    let mut module_map: HashMap<String, ModuleStats> = HashMap::new();

    for file in files {
        // Find the appropriate src root for this file
        let src_root = crate_info
            .src_dirs
            .iter()
            .find(|dir| file.path.starts_with(dir))
            .map(|p| p.as_path())
            .unwrap_or(&crate_info.root);

        let local_module = compute_module_name(&file.path, src_root);

        // Prefix with crate name for multi-crate workspaces
        let full_module_name = if local_module.is_empty() {
            crate_name.to_string()
        } else {
            format!("{}::{}", crate_name, local_module)
        };

        let module = module_map
            .entry(full_module_name.clone())
            .or_insert_with(|| ModuleStats::new(full_module_name));

        module.add_file(file.path.clone(), file.stats);
    }

    module_map.into_values().collect()
}

/// Count LOC in a single crate.
fn count_crate(crate_info: &CrateInfo, options: &CountOptions) -> Result<CrateStats> {
    let dirs: Vec<&Path> = crate_info.all_dirs();
    let files = discover_files_in_dirs(&dirs, &options.file_filter)?;

    let mut crate_stats = CrateStats::new(crate_info.name.clone(), crate_info.root.clone());

    for file_path in files {
        let stats = gather_stats_for_path(&file_path)?;
        let file_stats = FileStats::new(file_path, stats);
        crate_stats.add_file(file_stats);
    }

    Ok(crate_stats)
}

/// Count LOC in a directory (non-workspace mode).
///
/// Use this when you want to count files in a directory without
/// Cargo workspace awareness.
///
/// # Example
///
/// ```rust
/// use rustloclib::{count_directory, FilterConfig};
/// use std::fs;
/// use tempfile::tempdir;
///
/// let dir = tempdir().unwrap();
/// let src = dir.path().join("src");
/// fs::create_dir(&src).unwrap();
/// fs::write(src.join("lib.rs"), "pub fn hello() {}\n").unwrap();
/// fs::write(src.join("util.rs"), "pub fn util() {\n    // helper\n}\n").unwrap();
///
/// let filter = FilterConfig::new();
/// let result = count_directory(&src, &filter).unwrap();
/// assert_eq!(result.files.len(), 2);
/// ```
pub fn count_directory(path: impl AsRef<Path>, filter: &FilterConfig) -> Result<CountResult> {
    let path = path.as_ref();

    if !path.exists() {
        return Err(RustlocError::PathNotFound(path.to_path_buf()));
    }

    let files = discover_files(path, filter)?;

    let mut result = CountResult::new();
    result.root = path.to_path_buf();

    for file_path in files {
        let stats = gather_stats_for_path(&file_path)?;
        result.total += stats;
        result.file_count += 1;
        result.files.push(FileStats::new(file_path, stats));
    }

    Ok(result)
}

/// Count LOC in a single file.
///
/// # Example
///
/// ```rust
/// use rustloclib::count_file;
/// use std::fs;
/// use tempfile::tempdir;
///
/// let dir = tempdir().unwrap();
/// let file_path = dir.path().join("main.rs");
/// fs::write(&file_path, "fn main() {\n    println!(\"Hello\");\n}\n").unwrap();
///
/// let stats = count_file(&file_path).unwrap();
/// assert_eq!(stats.code, 3);
/// ```
pub fn count_file(path: impl AsRef<Path>) -> Result<Locs> {
    gather_stats_for_path(path)
}

#[cfg(test)]
mod tests {
    use super::*;
    use std::fs;
    use tempfile::tempdir;

    fn create_rust_file(path: &Path, content: &str) {
        if let Some(parent) = path.parent() {
            fs::create_dir_all(parent).unwrap();
        }
        fs::write(path, content).unwrap();
    }

    fn create_simple_project(root: &Path) {
        // Cargo.toml
        fs::write(
            root.join("Cargo.toml"),
            r#"[package]
name = "test-project"
version = "0.1.0"
edition = "2021"
"#,
        )
        .unwrap();

        // src/main.rs
        create_rust_file(
            &root.join("src/main.rs"),
            r#"fn main() {
    println!("Hello");
}

#[cfg(test)]
mod tests {
    #[test]
    fn test_main() {
        assert!(true);
    }
}
"#,
        );

        // src/lib.rs
        create_rust_file(
            &root.join("src/lib.rs"),
            r#"//! Library documentation

/// A public function
pub fn hello() {
    println!("Hello from lib");
}
"#,
        );
    }

    fn create_workspace(root: &Path) {
        // Workspace Cargo.toml
        fs::write(
            root.join("Cargo.toml"),
            r#"[workspace]
members = ["crate-a", "crate-b"]
"#,
        )
        .unwrap();

        // crate-a
        fs::create_dir_all(root.join("crate-a/src")).unwrap();
        fs::write(
            root.join("crate-a/Cargo.toml"),
            r#"[package]
name = "crate-a"
version = "0.1.0"
edition = "2021"
"#,
        )
        .unwrap();
        create_rust_file(
            &root.join("crate-a/src/lib.rs"),
            r#"pub fn a() {
    println!("A");
}
"#,
        );

        // crate-b
        fs::create_dir_all(root.join("crate-b/src")).unwrap();
        fs::write(
            root.join("crate-b/Cargo.toml"),
            r#"[package]
name = "crate-b"
version = "0.1.0"
edition = "2021"
"#,
        )
        .unwrap();
        create_rust_file(
            &root.join("crate-b/src/lib.rs"),
            r#"pub fn b() {
    println!("B");
}

// A comment
"#,
        );
    }

    #[test]
    fn test_count_directory() {
        let temp = tempdir().unwrap();
        let src = temp.path().join("src");
        fs::create_dir_all(&src).unwrap();

        create_rust_file(
            &src.join("main.rs"),
            r#"fn main() {
    println!("Hello");
}
"#,
        );

        let filter = FilterConfig::new();
        let result = count_directory(&src, &filter).unwrap();

        assert_eq!(result.files.len(), 1);
        assert_eq!(result.total.code, 3);
    }

    #[test]
    fn test_count_file() {
        let temp = tempdir().unwrap();
        let file = temp.path().join("test.rs");

        create_rust_file(
            &file,
            r#"/// Doc comment
fn foo() {
    // Regular comment
    let x = 1;
}
"#,
        );

        let stats = count_file(&file).unwrap();

        assert_eq!(stats.docs, 1);
        assert_eq!(stats.code, 3); // fn, let, }
        assert_eq!(stats.comments, 1);
    }

    #[test]
    fn test_count_workspace() {
        let temp = tempdir().unwrap();
        create_workspace(temp.path());

        let result = count_workspace(
            temp.path(),
            CountOptions::new().aggregation(Aggregation::ByCrate),
        )
        .unwrap();

        assert_eq!(result.crates.len(), 2);
    }

    #[test]
    fn test_count_workspace_filtered() {
        let temp = tempdir().unwrap();
        create_workspace(temp.path());

        let options = CountOptions::new()
            .crates(vec!["crate-a".to_string()])
            .aggregation(Aggregation::ByCrate);
        let result = count_workspace(temp.path(), options).unwrap();

        assert_eq!(result.crates.len(), 1);
        assert_eq!(result.crates[0].name, "crate-a");
    }

    #[test]
    fn test_count_workspace_with_file_stats() {
        let temp = tempdir().unwrap();
        create_workspace(temp.path());

        let options = CountOptions::new().aggregation(Aggregation::ByFile);
        let result = count_workspace(temp.path(), options).unwrap();

        assert_eq!(result.files.len(), 2);
    }

    #[test]
    fn test_count_mixed_code_and_tests() {
        let temp = tempdir().unwrap();
        create_simple_project(temp.path());

        let result = count_workspace(temp.path(), CountOptions::new()).unwrap();

        // main.rs has 3 production code lines + test block
        // lib.rs has doc comment + code
        assert!(result.total.code > 0);
        assert!(result.total.tests > 0);
        assert!(result.total.docs > 0);
    }

    #[test]
    fn test_compute_module_name_root_files() {
        let src = Path::new("/project/src");
        assert_eq!(
            compute_module_name(Path::new("/project/src/lib.rs"), src),
            ""
        );
        assert_eq!(
            compute_module_name(Path::new("/project/src/main.rs"), src),
            ""
        );
        assert_eq!(
            compute_module_name(Path::new("/project/src/error.rs"), src),
            "error"
        );
    }

    #[test]
    fn test_compute_module_name_directory_aggregation() {
        let src = Path::new("/project/src");
        // All files in data/ aggregate to "data"
        assert_eq!(
            compute_module_name(Path::new("/project/src/data/mod.rs"), src),
            "data"
        );
        assert_eq!(
            compute_module_name(Path::new("/project/src/data/counter.rs"), src),
            "data"
        );
        assert_eq!(
            compute_module_name(Path::new("/project/src/data/stats.rs"), src),
            "data"
        );
    }

    #[test]
    fn test_compute_module_name_nested_directories() {
        let src = Path::new("/project/src");
        // Nested directories get their own module
        assert_eq!(
            compute_module_name(Path::new("/project/src/data/sub/foo.rs"), src),
            "data::sub"
        );
        assert_eq!(
            compute_module_name(Path::new("/project/src/data/sub/mod.rs"), src),
            "data::sub"
        );
    }

    #[test]
    fn test_compute_module_name_new_style_module() {
        let src = Path::new("/project/src");
        // New-style: data.rs (sibling to data/) maps to "data"
        // just like files inside data/ — they aggregate together
        assert_eq!(
            compute_module_name(Path::new("/project/src/data.rs"), src),
            "data"
        );
        assert_eq!(
            compute_module_name(Path::new("/project/src/data/counter.rs"), src),
            "data"
        );
    }

    #[test]
    fn test_module_aggregation_groups_files_by_directory() {
        let temp = tempdir().unwrap();
        let root = temp.path();

        // Create a project with multiple modules
        fs::write(
            root.join("Cargo.toml"),
            "[package]\nname = \"test-proj\"\nversion = \"0.1.0\"\nedition = \"2021\"\n",
        )
        .unwrap();

        create_rust_file(&root.join("src/lib.rs"), "pub mod data;\npub mod utils;\n");
        create_rust_file(
            &root.join("src/data/mod.rs"),
            "pub mod counter;\npub mod stats;\n",
        );
        create_rust_file(&root.join("src/data/counter.rs"), "pub fn count() {}\n");
        create_rust_file(&root.join("src/data/stats.rs"), "pub fn stats() {}\n");
        create_rust_file(&root.join("src/utils.rs"), "pub fn helper() {}\n");

        let options = CountOptions::new().aggregation(Aggregation::ByModule);
        let result = count_workspace(root, options).unwrap();

        let module_names: Vec<&str> = result.modules.iter().map(|m| m.name.as_str()).collect();

        // data/mod.rs, data/counter.rs, data/stats.rs all aggregate under "test-proj::data"
        assert!(module_names.contains(&"test-proj::data"));
        // utils.rs is a root-level module
        assert!(module_names.contains(&"test-proj::utils"));
        // lib.rs maps to the crate root
        assert!(module_names.contains(&"test-proj"));
        // Should NOT have per-file entries
        assert!(!module_names.contains(&"test-proj::data::counter"));
        assert!(!module_names.contains(&"test-proj::data::stats"));
    }
}