#!/usr/bin/env python3
"""
Extract all tar archives under train/ and val/ directories.
"""
from __future__ import annotations

import argparse
import tarfile
from pathlib import Path


def iter_archives(root: Path) -> list[Path]:
    patterns = ("*.tar", "*.tar.gz", "*.tgz")
    archives: list[Path] = []
    for pattern in patterns:
        archives.extend(root.rglob(pattern))
    return sorted(set(archives))


def extract_archive(archive: Path, dest: Path, *, dry_run: bool) -> None:
    if dry_run:
        print(f"[dry-run] {archive} -> {dest}")
        return
    with tarfile.open(archive, "r:*") as tar:
        tar.extractall(path=dest)
    print(f"extracted {archive} -> {dest}")


def delete_archives(archives: list[Path]) -> None:
    """Delete archives after successful extraction to save space."""
    for archive in archives:
        try:
            archive.unlink()
            print(f"deleted {archive}")
        except FileNotFoundError:
            continue


def remove_dot_underscore_files(root: Path) -> None:
    """Remove macOS resource fork files like ._foo."""
    for path in root.rglob("._*"):
        try:
            path.unlink()
            print(f"removed {path}")
        except FileNotFoundError:
            continue


def main() -> int:
    parser = argparse.ArgumentParser(
        description="Extract tar archives under train/ and val/ directories."
    )
    parser.add_argument(
        "--root",
        type=Path,
        default=Path("."),
        help="Project root containing train/ and val/ (default: current directory).",
    )
    parser.add_argument(
        "--dry-run",
        action="store_true",
        help="List archives without extracting.",
    )
    args = parser.parse_args()

    root = args.root.resolve()
    targets = [root / "train", root / "val"]
    archives: list[Path] = []
    for target in targets:
        if target.is_dir():
            archives.extend(iter_archives(target))
        else:
            print(f"skip missing directory: {target}")

    if not archives:
        print("no archives found")
        return 0

    for archive in archives:
        extract_archive(archive, archive.parent, dry_run=args.dry_run)

    if not args.dry_run:
        delete_archives(archives)
        for target in targets:
            if target.is_dir():
                remove_dot_underscore_files(target)

    return 0


if __name__ == "__main__":
    raise SystemExit(main())