#!/usr/bin/env python3
from pathlib import Path
import subprocess

import click


@click.command()
@click.option('--allow-unknown', is_flag=True,
              help='Error out if one of the directories from the given list does not exist')
@click.option('--base-dir', type=Path, default='.', show_default=True,
              help='Base directory where the channel directories get created')
@click.argument('CHANNEL_FILE', required=True)
def download(allow_unknown, base_dir, channel_file):
    """Mirror channels from YouTube

    The list of channels needs to be provided via CHANNEL_FILE. The format of the file should be one channel per line.
    each line consisting of the directory name and the URL to download the videos joined by a semicolon.
    """
    base_dir = base_dir.resolve()

    channels = {}
    with open(channel_file) as f:
        for line in f:
            line = line.strip()
            if line.startswith('#'):
                continue
            
            dir_name, url = line.split(';')
            channels[dir_name] = url

    if not allow_unknown:
        error = False
        for dir_name in channels:
            if (base_dir / dir_name).is_dir():
                continue

            print(f"Error: '{dir_name}' is an unknown channel")
            error = True

        if error:
            raise click.ClickException("Unknown channels and '--allow-unknown' not given")

    for dir_name, url in channels.items():
        target_dir = base_dir / dir_name

        print(f"Starting download for {dir_name}")

        if not target_dir.exists():
            target_dir.mkdir()

        cmd = [
            'yt-dlp',
            '-o', '%(upload_date)s - %(title)s - %(id)s.%(ext)s',
            '--sleep-interval', '30',
            '--max-sleep-interval', '300',
            '--download-archive', target_dir / '.archive',
            '--break-on-existing',
            '--write-thumbnail',
            url
        ]
        subprocess.run(cmd, check=True, cwd=target_dir) 


if __name__ == '__main__':
    download()