purger-core 0.4.0

use anyhow::{Context, Result};
use serde::{Deserialize, Serialize};
use std::fs;
use std::path::{Path, PathBuf};
use std::time::SystemTime;
use tracing::debug;
use walkdir::WalkDir;

/// Rust project metadata
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct RustProject {
    pub path: PathBuf,
    pub name: String,
    pub target_size: u64,
    pub last_modified: SystemTime,
    pub is_workspace: bool,
    pub has_target: bool,
}

impl RustProject {
    /// Create a `RustProject` from a directory path
    pub fn from_path<P: AsRef<Path>>(path: P) -> Result<Self> {
        Self::from_path_impl(path, false)
    }

    /// Create a `RustProject` from a directory path, without computing target size
    pub fn from_path_lazy<P: AsRef<Path>>(path: P) -> Result<Self> {
        Self::from_path_impl(path, true)
    }

    fn from_path_impl<P: AsRef<Path>>(path: P, lazy_size: bool) -> Result<Self> {
        let path = path.as_ref().to_path_buf();
        let cargo_toml_path = path.join("Cargo.toml");

        if !cargo_toml_path.exists() {
            anyhow::bail!("No Cargo.toml found at {:?}", path);
        }

        // 一次性读取和解析 TOML，避免重复 IO
        let (name, is_workspace) = match Self::parse_cargo_toml(&cargo_toml_path, &path) {
            Ok(result) => result,
            Err(err) => {
                debug!(
                    "Failed to parse Cargo.toml at {:?}: {}",
                    cargo_toml_path, err
                );
                (Self::fallback_project_name(&path), false)
            }
        };
        let target_path = path.join("target");
        let has_target = target_path.exists();

        let (target_size, last_modified) = if has_target {
            let modified = fs::metadata(&target_path)
                .context("Failed to get target directory metadata")?
                .modified()
                .context("Failed to get target directory modification time")?;
            let size = if lazy_size {
                0
            } else {
                Self::calculate_directory_size_fast(&target_path).unwrap_or(0)
            };
            (size, modified)
        } else {
            (0, SystemTime::UNIX_EPOCH)
        };

        Ok(RustProject {
            path,
            name,
            target_size,
            last_modified,
            is_workspace,
            has_target,
        })
    }

    /// Parse Cargo.toml once to extract package name and workspace info
    fn parse_cargo_toml(cargo_toml_path: &Path, project_path: &Path) -> Result<(String, bool)> {
        let content = fs::read_to_string(cargo_toml_path).context("Failed to read Cargo.toml")?;
        let parsed: toml::Value = toml::from_str(&content).context("Failed to parse Cargo.toml")?;

        // 提取项目名称
        let name = parsed
            .get("package")
            .and_then(|p| p.get("name"))
            .and_then(|n| n.as_str())
            .map(|s| s.to_string())
            .unwrap_or_else(|| Self::fallback_project_name(project_path));

        // 检查是否为workspace项目
        let is_workspace = parsed.get("workspace").is_some();

        Ok((name, is_workspace))
    }

    fn fallback_project_name(project_path: &Path) -> String {
        project_path
            .file_name()
            .and_then(|n| n.to_str())
            .unwrap_or("unknown")
            .to_string()
    }

    /// Check whether this is a workspace project (kept for backward compatibility)
    fn is_workspace_project(cargo_toml_path: &Path) -> Result<bool> {
        let content = fs::read_to_string(cargo_toml_path).context("Failed to read Cargo.toml")?;
        let parsed: toml::Value = toml::from_str(&content).context("Failed to parse Cargo.toml")?;
        Ok(parsed.get("workspace").is_some())
    }

    /// Extract project name from Cargo.toml (kept for backward compatibility)
    fn extract_project_name(cargo_toml_path: &Path) -> Option<String> {
        let content = fs::read_to_string(cargo_toml_path).ok()?;
        let parsed: toml::Value = toml::from_str(&content).ok()?;

        parsed
            .get("package")
            .and_then(|p| p.get("name"))
            .and_then(|n| n.as_str())
            .map(|s| s.to_string())
    }

    /// Calculate directory size
    fn calculate_directory_size(dir: &Path) -> Result<u64> {
        let mut total_size = 0u64;

        for entry in WalkDir::new(dir).into_iter().filter_map(|e| e.ok()) {
            if entry.file_type().is_file() {
                if let Ok(metadata) = entry.metadata() {
                    total_size += metadata.len();
                }
            }
        }

        Ok(total_size)
    }

    /// Calculate directory size (parallelized)
    fn calculate_directory_size_fast(dir: &Path) -> Result<u64> {
        use rayon::prelude::*;
        use std::sync::atomic::{AtomicU64, Ordering};

        // 使用原子计数器避免收集所有条目到 Vec
        let total_size = AtomicU64::new(0);

        // 并行遍历，直接累加大小
        WalkDir::new(dir)
            .into_iter()
            .par_bridge() // 将串行迭代器转换为并行迭代器
            .filter_map(|entry| entry.ok())
            .filter(|entry| entry.file_type().is_file())
            .for_each(|entry| {
                if let Ok(metadata) = entry.metadata() {
                    total_size.fetch_add(metadata.len(), Ordering::Relaxed);
                }
            });

        Ok(total_size.into_inner())
    }

    /// Get a human-readable target size string
    pub fn formatted_size(&self) -> String {
        crate::format_bytes(self.get_target_size())
    }

    /// Get target directory size (compute on demand if needed)
    pub fn get_target_size(&self) -> u64 {
        if self.target_size > 0 {
            return self.target_size;
        }

        if !self.has_target {
            return 0;
        }

        // 按需计算大小
        let target_path = self.target_path();
        Self::calculate_directory_size_fast(&target_path).unwrap_or(0)
    }

    /// Get relative path from a base directory
    pub fn relative_path(&self, base: &Path) -> PathBuf {
        self.path
            .strip_prefix(base)
            .unwrap_or(&self.path)
            .to_path_buf()
    }

    /// Check if target directory exists
    pub fn target_exists(&self) -> bool {
        self.path.join("target").exists()
    }

    /// Get target directory path
    pub fn target_path(&self) -> PathBuf {
        self.path.join("target")
    }
}

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

    #[test]
    fn test_is_workspace_project() {
        let temp_dir = TempDir::new().unwrap();
        let cargo_toml = temp_dir.path().join("Cargo.toml");

        // 测试普通项目
        fs::write(
            &cargo_toml,
            r#"
[package]
name = "test"
version = "0.1.0"
"#,
        )
        .unwrap();

        assert!(!RustProject::is_workspace_project(&cargo_toml).unwrap());

        // 测试workspace项目
        fs::write(
            &cargo_toml,
            r#"
[workspace]
members = ["crate1", "crate2"]
"#,
        )
        .unwrap();

        assert!(RustProject::is_workspace_project(&cargo_toml).unwrap());
    }

    #[test]
    fn test_extract_project_name() {
        let temp_dir = TempDir::new().unwrap();
        let cargo_toml = temp_dir.path().join("Cargo.toml");

        fs::write(
            &cargo_toml,
            r#"
[package]
name = "my-awesome-project"
version = "0.1.0"
"#,
        )
        .unwrap();

        let name = RustProject::extract_project_name(&cargo_toml);
        assert_eq!(name, Some("my-awesome-project".to_string()));
    }

    #[test]
    fn test_from_path_with_target() -> Result<()> {
        let temp_dir = TempDir::new()?;
        let project_dir = temp_dir.path().join("test_project");
        std::fs::create_dir_all(&project_dir)?;

        // 创建Cargo.toml
        let cargo_toml = r#"
[package]
name = "test_project"
version = "0.1.0"
edition = "2021"
"#;
        std::fs::write(project_dir.join("Cargo.toml"), cargo_toml)?;

        // 创建target目录和一些文件
        let target_dir = project_dir.join("target");
        std::fs::create_dir_all(&target_dir)?;
        std::fs::write(target_dir.join("test.txt"), "test content")?;

        let project = RustProject::from_path(&project_dir)?;
        assert_eq!(project.name, "test_project");
        assert!(project.has_target);
        assert!(project.target_size > 0);

        Ok(())
    }

    #[test]
    fn test_from_path_without_target() -> Result<()> {
        let temp_dir = TempDir::new()?;
        let project_dir = temp_dir.path().join("test_project");
        std::fs::create_dir_all(&project_dir)?;

        // 创建Cargo.toml
        let cargo_toml = r#"
[package]
name = "test_project"
version = "0.1.0"
edition = "2021"
"#;
        std::fs::write(project_dir.join("Cargo.toml"), cargo_toml)?;

        let project = RustProject::from_path(&project_dir)?;
        assert_eq!(project.name, "test_project");
        assert!(!project.has_target);
        assert_eq!(project.target_size, 0);

        Ok(())
    }

    #[test]
    fn test_from_path_invalid() {
        let temp_dir = TempDir::new().unwrap();
        let project_dir = temp_dir.path().join("invalid_project");
        std::fs::create_dir_all(&project_dir).unwrap();

        // 不创建Cargo.toml
        let result = RustProject::from_path(&project_dir);
        assert!(result.is_err());
    }

    #[test]
    fn test_formatted_size() {
        let project = RustProject {
            path: PathBuf::from("/test"),
            name: "test".to_string(),
            target_size: 1024,
            last_modified: SystemTime::now(),
            is_workspace: false,
            has_target: true,
        };

        let formatted = project.formatted_size();
        assert_eq!(formatted, "1.00 KB");
    }

    #[test]
    fn test_relative_path() {
        let project = RustProject {
            path: PathBuf::from("/home/user/projects/my_project"),
            name: "my_project".to_string(),
            target_size: 0,
            last_modified: SystemTime::now(),
            is_workspace: false,
            has_target: false,
        };

        let base = Path::new("/home/user/projects");
        let relative = project.relative_path(base);
        assert_eq!(relative, PathBuf::from("my_project"));
    }

    #[test]
    fn test_target_exists() -> Result<()> {
        let temp_dir = TempDir::new()?;
        let project_dir = temp_dir.path().join("test_project");
        std::fs::create_dir_all(&project_dir)?;

        let project = RustProject {
            path: project_dir.clone(),
            name: "test".to_string(),
            target_size: 0,
            last_modified: SystemTime::now(),
            is_workspace: false,
            has_target: false,
        };

        // 最初target不存在
        assert!(!project.target_exists());

        // 创建target目录
        std::fs::create_dir_all(project_dir.join("target"))?;
        assert!(project.target_exists());

        Ok(())
    }

    #[test]
    fn test_target_path() {
        let project = RustProject {
            path: PathBuf::from("/test/project"),
            name: "test".to_string(),
            target_size: 0,
            last_modified: SystemTime::now(),
            is_workspace: false,
            has_target: false,
        };

        let target_path = project.target_path();
        assert_eq!(target_path, PathBuf::from("/test/project/target"));
    }
}