from argparse import ArgumentParser
from pathlib import Path
from logging import basicConfig, warning, WARNING
from shutil import copyfile

def main(music_folder: Path):
    music_folder = music_folder.resolve()

    for m3u in music_folder.rglob("*.m3u"):
        copyfile(m3u, m3u.with_suffix(".m3u.bak"))

        with m3u.open("r") as contents:
            tracks = [Path(p).resolve() for p in contents.readlines()]

        if not all(music_folder in track.parents for track in tracks):
            warning(f"{m3u} contains references to tracks that are not in {music_folder} and will be skipped")
            continue
       
        with m3u.open("w") as updated_contents:
            for track in tracks:
                updated_contents.write(str(track.relative_to(m3u, walk_up=True)).replace("\\", "/"))


if __name__ == "__main__":
    basicConfig(
        level=WARNING,
    )
    
    parser = ArgumentParser(
        description=""
    )

    parser.add_argument(
        "music_folder",
        required=True,
        type=Path
    )

    args = parser.parse_args()

    main(args.music_folder)