slimg 0.1.3

pub mod convert;
pub mod optimize;
pub mod resize;

use std::fs;
use std::path::{Path, PathBuf};
use std::sync::Mutex;

use clap::ValueEnum;
use indicatif::{ProgressBar, ProgressStyle};
use slimg_core::Format;

/// Image format argument for CLI (excludes JXL which cannot be encoded).
#[derive(Debug, Clone, Copy, ValueEnum)]
pub enum FormatArg {
    Jpeg,
    Png,
    Webp,
    Avif,
    Qoi,
}

impl FormatArg {
    pub fn into_format(self) -> Format {
        match self {
            Self::Jpeg => Format::Jpeg,
            Self::Png => Format::Png,
            Self::Webp => Format::WebP,
            Self::Avif => Format::Avif,
            Self::Qoi => Format::Qoi,
        }
    }
}

/// Known image file extensions that slimg can process.
const IMAGE_EXTENSIONS: &[&str] = &["jpg", "jpeg", "png", "webp", "avif", "jxl", "qoi"];

/// Collect image files from a path.
///
/// - If `path` is a file, returns it as a single-element vec.
/// - If `path` is a directory, lists entries (recursively if `recursive` is true),
///   filters by image extensions, and returns sorted results.
pub(crate) fn collect_files(path: &Path, recursive: bool) -> anyhow::Result<Vec<PathBuf>> {
    if path.is_file() {
        return Ok(vec![path.to_path_buf()]);
    }

    if !path.is_dir() {
        anyhow::bail!("{} is not a file or directory", path.display());
    }

    let mut files = Vec::new();
    collect_dir(path, recursive, &mut files)?;
    files.sort();
    Ok(files)
}

/// Configure rayon's global thread pool.
/// When `jobs` is `None`, rayon defaults to the number of logical CPUs.
pub(crate) fn configure_thread_pool(jobs: Option<usize>) -> anyhow::Result<()> {
    if let Some(n) = jobs {
        rayon::ThreadPoolBuilder::new()
            .num_threads(n)
            .build_global()
            .map_err(|e| anyhow::anyhow!("failed to configure thread pool: {e}"))?;
    }
    Ok(())
}

/// Create a progress bar for batch processing.
/// Returns a hidden bar when processing a single file.
pub(crate) fn make_progress_bar(total: usize) -> ProgressBar {
    if total <= 1 {
        return ProgressBar::hidden();
    }

    let pb = ProgressBar::new(total as u64);
    pb.set_style(
        ProgressStyle::default_bar()
            .template("[{elapsed_precise}] [{bar:30}] {pos}/{len} ({eta})")
            .unwrap()
            .progress_chars("=> "),
    );
    pb
}

/// Write data to a file safely. When overwriting, writes to a temp file first
/// and renames on success, so the original is preserved if encoding fails.
pub(crate) fn safe_write(path: &Path, data: &[u8], overwrite: bool) -> anyhow::Result<()> {
    if let Some(parent) = path.parent() {
        fs::create_dir_all(parent)?;
    }

    if overwrite && path.exists() {
        let mut tmp = path.as_os_str().to_os_string();
        tmp.push(".slimg_tmp");
        let tmp = PathBuf::from(tmp);
        fs::write(&tmp, data)?;
        fs::rename(&tmp, path)?;
    } else {
        fs::write(path, data)?;
    }

    Ok(())
}

/// Collector for errors that occur during batch processing.
/// Thread-safe — can be shared across rayon workers.
pub(crate) struct ErrorCollector {
    errors: Mutex<Vec<(PathBuf, String)>>,
}

impl ErrorCollector {
    pub fn new() -> Self {
        Self {
            errors: Mutex::new(Vec::new()),
        }
    }

    pub fn push(&self, path: &Path, err: &anyhow::Error) {
        self.errors
            .lock()
            .unwrap()
            .push((path.to_path_buf(), format!("{err:#}")));
    }

    /// Print error summary and return the error count.
    pub fn summarize(&self, pb: &ProgressBar) -> usize {
        let errors = self.errors.lock().unwrap();
        if errors.is_empty() {
            return 0;
        }

        pb.println(format!("\n{} file(s) failed:", errors.len()));
        for (path, msg) in errors.iter() {
            pb.println(format!("  {} — {}", path.display(), msg));
        }

        errors.len()
    }
}

fn collect_dir(dir: &Path, recursive: bool, out: &mut Vec<PathBuf>) -> anyhow::Result<()> {
    for entry in std::fs::read_dir(dir)? {
        let entry = entry?;
        let path = entry.path();

        if path.is_dir() && recursive {
            collect_dir(&path, recursive, out)?;
        } else if path.is_file()
            && let Some(ext) = path.extension().and_then(|e| e.to_str())
            && IMAGE_EXTENSIONS.contains(&ext.to_ascii_lowercase().as_str())
        {
            out.push(path);
        }
    }
    Ok(())
}

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

    // ── safe_write ──────────────────────────────────────────

    #[test]
    fn safe_write_creates_new_file() {
        let dir = TempDir::new().unwrap();
        let path = dir.path().join("out.bin");

        safe_write(&path, b"hello", false).unwrap();

        assert_eq!(fs::read(&path).unwrap(), b"hello");
    }

    #[test]
    fn safe_write_creates_parent_dirs() {
        let dir = TempDir::new().unwrap();
        let path = dir.path().join("a/b/c/out.bin");

        safe_write(&path, b"nested", false).unwrap();

        assert_eq!(fs::read(&path).unwrap(), b"nested");
    }

    #[test]
    fn safe_write_overwrite_replaces_content() {
        let dir = TempDir::new().unwrap();
        let path = dir.path().join("file.jpg");
        fs::write(&path, b"original").unwrap();

        safe_write(&path, b"optimized", true).unwrap();

        assert_eq!(fs::read(&path).unwrap(), b"optimized");
    }

    #[test]
    fn safe_write_overwrite_leaves_no_temp_file() {
        let dir = TempDir::new().unwrap();
        let path = dir.path().join("file.jpg");
        fs::write(&path, b"original").unwrap();

        safe_write(&path, b"new", true).unwrap();

        let tmp = dir.path().join("file.jpg.slimg_tmp");
        assert!(!tmp.exists(), "temp file should be cleaned up after rename");
    }

    #[test]
    fn safe_write_overwrite_no_collision_different_extensions() {
        let dir = TempDir::new().unwrap();
        let jpg = dir.path().join("photo.jpg");
        let png = dir.path().join("photo.png");
        fs::write(&jpg, b"jpg-original").unwrap();
        fs::write(&png, b"png-original").unwrap();

        // Simulate parallel overwrite of both files
        safe_write(&jpg, b"jpg-new", true).unwrap();
        safe_write(&png, b"png-new", true).unwrap();

        assert_eq!(fs::read(&jpg).unwrap(), b"jpg-new");
        assert_eq!(fs::read(&png).unwrap(), b"png-new");

        // Verify distinct temp paths
        let jpg_tmp = dir.path().join("photo.jpg.slimg_tmp");
        let png_tmp = dir.path().join("photo.png.slimg_tmp");
        assert!(!jpg_tmp.exists());
        assert!(!png_tmp.exists());
    }

    #[test]
    fn safe_write_overwrite_preserves_original_on_nonexistent_target() {
        // When the file doesn't exist yet, overwrite=true still creates it
        let dir = TempDir::new().unwrap();
        let path = dir.path().join("new.jpg");

        safe_write(&path, b"data", true).unwrap();

        assert_eq!(fs::read(&path).unwrap(), b"data");
    }

    // ── ErrorCollector ──────────────────────────────────────

    #[test]
    fn error_collector_empty_returns_zero() {
        let ec = ErrorCollector::new();
        let pb = ProgressBar::hidden();

        assert_eq!(ec.summarize(&pb), 0);
    }

    #[test]
    fn error_collector_counts_errors() {
        let ec = ErrorCollector::new();
        ec.push(Path::new("a.jpg"), &anyhow::anyhow!("decode failed"));
        ec.push(Path::new("b.png"), &anyhow::anyhow!("io error"));

        let pb = ProgressBar::hidden();
        assert_eq!(ec.summarize(&pb), 2);
    }

    #[test]
    fn error_collector_is_thread_safe() {
        use rayon::prelude::*;

        let ec = ErrorCollector::new();
        let paths: Vec<PathBuf> = (0..100)
            .map(|i| PathBuf::from(format!("{i}.jpg")))
            .collect();

        paths.par_iter().for_each(|p| {
            ec.push(p, &anyhow::anyhow!("error"));
        });

        let pb = ProgressBar::hidden();
        assert_eq!(ec.summarize(&pb), 100);
    }

    // ── collect_files ───────────────────────────────────────

    #[test]
    fn collect_files_single_file() {
        let dir = TempDir::new().unwrap();
        let path = dir.path().join("test.jpg");
        fs::write(&path, b"fake").unwrap();

        let files = collect_files(&path, false).unwrap();
        assert_eq!(files, vec![path]);
    }

    #[test]
    fn collect_files_filters_by_extension() {
        let dir = TempDir::new().unwrap();
        fs::write(dir.path().join("a.jpg"), b"").unwrap();
        fs::write(dir.path().join("b.txt"), b"").unwrap();
        fs::write(dir.path().join("c.png"), b"").unwrap();

        let files = collect_files(dir.path(), false).unwrap();
        assert_eq!(files.len(), 2);
        assert!(files.iter().all(|f| {
            let ext = f.extension().unwrap().to_str().unwrap();
            ext == "jpg" || ext == "png"
        }));
    }

    #[test]
    fn collect_files_recursive() {
        let dir = TempDir::new().unwrap();
        fs::write(dir.path().join("a.jpg"), b"").unwrap();
        let sub = dir.path().join("sub");
        fs::create_dir(&sub).unwrap();
        fs::write(sub.join("b.png"), b"").unwrap();

        let non_recursive = collect_files(dir.path(), false).unwrap();
        assert_eq!(non_recursive.len(), 1);

        let recursive = collect_files(dir.path(), true).unwrap();
        assert_eq!(recursive.len(), 2);
    }
}