#!/usr/bin/env python3

from datetime import timedelta
from email import message_from_file
import re
import sys
import youtube_dl


FROM    = "{uploader} <noreply@youtube.com>"
SUBJECT = "{title}"
CONTENT = """\
{uploader} just uploaded a video
{title} ({duration})

{webpage_url}

Description
───────────────────────────────────────────────────────────────────────

{description}

───────────────────────────────────────────────────────────────────────

Manage notifications: https://www.youtube.com/subscription_manager
"""


def parse_file(fd):
    msg = message_from_file(fd)

    payload = ""
    if msg.is_multipart():
        for part in msg.get_payload():
            if part.get_content_type() != 'text/plain':
                continue
            charset = part.get_content_charset()
            payload = part.get_payload(decode=True).decode(charset)
    else:
        payload = msg.get_payload(decode=True).decode(charset)

    url = re.search(r'^https?://www.youtube.com/watch\?v=[\w-]{11}', payload, re.MULTILINE).group()
    # print(url)
    with youtube_dl.YoutubeDL({'quiet' : True}) as ytdl:
        info = ytdl.extract_info(url, download=False, force_generic_extractor=True)

    if info is None:
        return False

    info['duration'] = timedelta(seconds=info['duration'])

    del msg['From']
    msg['From'] = FROM.format(**info)

    del msg['Subject']
    msg['Subject'] = SUBJECT.format(**info)

    msg.set_payload(CONTENT.format(**info))

    return msg


if __name__ == "__main__":
    if len(sys.argv) == 1:
        msg = parse_file(sys.stdin)
    else:
        with open(sys.argv[1], 'r') as fd:
            msg = parse_file(fd)
    print(msg)