from argparse import ArgumentParser
import os, subprocess


def delete_if_exists(path):
    if os.path.exists(path) and os.path.isfile(path):
        os.remove(path)


def run_ffmpeg(ffmpeg_args):
    ffmpeg_args.insert(0, "ffmpeg")
    ffmpeg_args = [str(arg) for arg in ffmpeg_args]
    print(" ".join(ffmpeg_args))
    result = subprocess.run(ffmpeg_args, capture_output=True, text=True)
    if result.stdout:
        print(result.stdout)
    if result.stderr:
        print(result.stderr)


def extract_subs(input_file):
    subs_path = "subs.ssa"
    delete_if_exists(subs_path)
    run_ffmpeg(["-i", input_file, "-map", "0:s:0", subs_path])
    return subs_path


def create_gif(input_file, subs_path, start_time, duration, width, height, framerate):
    subs_arg = f"subtitles={subs_path}," if subs_path else ""
    ffmpeg_args = ["-i", input_file, "-ss", start_time, "-vf", f"{subs_arg}scale={width}:{height}"]
    if duration:
        ffmpeg_args.append("-t")
        ffmpeg_args.append(duration)
    if framerate:
        ffmpeg_args.append("-r")
        ffmpeg_args.append(framerate)

    output_path = f"{os.path.splitext(input_file)[0]}.gif"
    delete_if_exists(output_path)
    ffmpeg_args.append(output_path)
    run_ffmpeg(ffmpeg_args)


if __name__ == '__main__':
    parser = ArgumentParser(prog="ffmpeg-gif", description="A tool for converting a video file with subs to a gif")
    parser.add_argument("-i", "--input_file", required=True, type=str)
    parser.add_argument("-ss", "--start_time", default="00:00:00", type=str)
    parser.add_argument("-t", "--duration", type=str)
    parser.add_argument("-x", "--width", default=640, type=int)
    parser.add_argument("-y", "--height", default=360, type=int)
    parser.add_argument("-r", "--framerate", default=10, type=int)
    parser.add_argument("-s", "--subs", action="store_true")

    args = parser.parse_args()
    subs = None
    if args.subs:
        subs = extract_subs(args.input_file)

    create_gif(args.input_file, subs, args.start_time, args.duration, args.width, args.height, args.framerate)