#!/usr/bin/env python3.9
import argparse
import logging
import subprocess
import sys
from pathlib import Path


def parse_args(argv: list[str]):
    arger = argparse.ArgumentParser(formatter_class=argparse.ArgumentDefaultsHelpFormatter)
    arger.add_argument("files", nargs="+", type=Path, help="Video paths")
    arger.add_argument("-o", dest="output_path", type=Path, help="Output path", required=True)
    if len(argv) == 0:
        arger.print_help()
        exit(1)

    return arger.parse_args(argv)


def combine_videos(videos: list[Path], save_path: Path) -> Path:
    """
    Combine multiple videos into one.
    :param videos: List of video paths.
    :param save_path: Path to save the combined video.
    :return: Path to the combined video.
    """

    # file '/path/to/file1'
    # file '/path/to/file2'
    # file '/path/to/file3'
    #
    # $ ffmpeg -f concat -safe 0 -i mylist.txt -c copy output.mp4

    # ffmpeg -f concat -safe 0 -i mylist.txt -c copy output.mp4
    stdin = "\n".join(f"file '{video.absolute()}'" for video in videos if video.is_file())
    # fmt: off
    args = [
        'ffmpeg',
        '-protocol_whitelist', 'file,pipe',
        '-f', 'concat',
        '-safe', '0',
        '-i', '-',
        '-c', 'copy',
        str(save_path),
    ]
    # fmt: on
    logging.info(f"calling ffmpeg with {args=} and {stdin=}")
    subprocess.run(args, input=stdin.encode(), check=True)
    return save_path


def main():
    logging.basicConfig(level=logging.INFO)
    args = parse_args(sys.argv[1:])
    paths = [Path(f) for f in args.files]
    combine_videos(videos=paths, save_path=args.output_path)


if __name__ == "__main__":
    main()