import argparse
from pathlib import Path
import random
import string
import subprocess
from typing import Any, Dict, List, Tuple


def get_args() -> Dict[str, Any]:
    parser = argparse.ArgumentParser(
        prog='video_to_gif.py',
        description='Use ffmpeg to make GIFs from videos',
        epilog='— Be gay and do crime')
    parser.add_argument('input', type=str, metavar='INPUT', nargs='+',
                        help="input file, supports passing a glob like /Users/MyName/Videos/*.mov")
    parser.add_argument('-w', '--width', type=str, default='960',
                        help='width of the GIF in pixels, respecting aspect ratio (default: 960)')
    parser.add_argument('-r', '--framerate', type=str,
                        default='12', help='framerate of GIF (default: 12)')
    parser.add_argument('-s', '--scaler', type=str, choices=get_scaling_algorithms(),
                        default='lanczos', help='scaling algorithm to use (default: lanczos)')
    parser.add_argument('-i', '--interpolate', type=str, choices=get_interpolation_methods(),
                        default='none', help='interpolation method to use (default: none)')
    parser.add_argument('-t', '--tag', type=str, default=get_tag(),
                        help='optional tag included in file name')
    return vars(parser.parse_args())


def get_scaling_algorithms() -> List[str]:
    return ['fast_bilinear', 'bilinear', 'bicubic', 'experimental', 'neighbor',
            'area', 'bicublin', 'gauss', 'sinc', 'lanczos', 'spline']


def get_interpolation_methods() -> List[str]:
    return ['none', 'dup', 'blend', 'mci']


# TODO: Figure out how to specify both scaling and dithering algorithms.
def get_dithering_algorithms() -> List[str]:
    return ['none', 'auto', 'bayer', 'ed', 'a_dither', 'x_dither']


def get_tag() -> str:
    return ''.join(random.choices(string.ascii_uppercase + string.digits, k=5))


def call_ffmpeg(command: List[str]) -> bool:
    print("ffmpeg", ' '.join(command))
    full_command = ["ffmpeg", '-hide_banner', '-loglevel', 'error'] + command
    process = subprocess.run(full_command)
    return process.returncode == 0


def generate_gif_files(inputs: List[str], args: Dict[str, Any]) -> Dict[str, Tuple[bool, str]]:
    tag = args['tag']
    width = args['width']
    framerate = args['framerate']
    scaler = args['scaler']
    interpolate = args['interpolate']

    interpolate_cmd = ''
    if interpolate != 'none':
        interpolate_cmd = f"minterpolate=fps={ \
            framerate}:mi_mode={interpolate},"

    output_map = {}
    for input in inputs:
        file_name = f"{Path(input).stem}_{tag}.gif"
        full_path = f"{Path(input).parent}/{file_name}"
        command = ['-i', input, '-f', 'gif', '-r', f"{framerate}", '-filter_complex', f"{interpolate_cmd}scale={ \
            width}:-1:flags={scaler},split[v1][v2];[v1]palettegen[plt];[v2][plt]paletteuse", f"{full_path}"]
        success = call_ffmpeg(command)
        # Tuple of (was it successful?, path of output)
        output_map[input] = (success, full_path)

    return output_map


def make_gifs(args: Dict[str, Any]) -> None:
    inputs = args['input']
    output_map = generate_gif_files(inputs, args)
    successes = 0
    for input in output_map:
        entry = output_map[input]
        if entry[0]:
            print(f"Created {entry[1]} from {input}")
            successes += 1
    total = len(output_map)
    print(f"{successes} of {total} commands succeeded.")


def main() -> None:
    make_gifs(get_args())
    return


if __name__ == '__main__':
    main()