#!/usr/bin/python3
"""Download audio using youtube-dl.

Dependencies:
=============
* youtube-dl
"""

import argparse
import pathlib
import subprocess

# =========== Constants ==========
YOUTUBE_DL_BIN = '/usr/bin/youtube-dl'
DEFAULT_FILENAME = f"{pathlib.Path.home()}/Music/%(title)s.%(ext)s"

# ========== Error Codes ==========
E_NOURLS = 2

# =========== Functions ==========
if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    parser.add_argument('-b', '--batchfile',
                        type=str,
                        nargs=1,
                        help='provide the links from a text file')
    parser.add_argument('-f', '--format',
                        type=str,
                        default='opus',
                        help='the format to use')
    parser.add_argument('-n', '--filename',
                        type=str,
                        help='downloaded filename (without extension)')
    parser.add_argument('urls',
                        nargs='*',
                        help='video URLs')
    args = parser.parse_args()

    dl_opts = [YOUTUBE_DL_BIN,
               '--no-part',
               '--no-continue',
               '--extract-audio',
               '--audio-format={args.format}']

    # filename handling
    # if -b is used, DEFAULT_FILENAME must take precedence
    if args.filename:
        dl_opts.append('--output={args.filename}')
    else:
        dl_opts.append('--output={DEFAULT_FILENAME}')

    # URL handling
    if args.batchfile:
        dl_opts.append(f"--batch-file={args.batchfile}")
    elif not args.urls:
        print("URLs are required")
        exit(E_NOURLS)
    else:
        dl_opts.extend(args.urls)

    subprocess.run(dl_opts)