#!/usr/bin/env python3

import os
import opml
import feedparser
import youtube_dl
import sys
from pathlib import Path
import argparse
from time import time, mktime, strptime
from datetime import datetime
from dateutil.relativedelta import relativedelta

if sys.version_info.major < 3 and sys.version_info.minor < 6:
    raise Exception('Must be using Python 3.6 or greater')

if __name__ == '__main__':

    parser = argparse.ArgumentParser('Download YouTube subscriptions.')
    parser.add_argument('--save-directory', '-o',
                        dest='output',
                        default=None,
                        help='The directory to which to save the videos.')
    parser.add_argument('--retain', '-c',
                        dest='retain',
                        default=None,
                        help='Retain videos up to the given number of days since today.')
    parser.add_argument('--since', '-s',
                        dest='since',
                        default=None,
                        help='Only download videos newer than the given number of days.')
    parser.add_argument('--config-directory', '-f',
                        dest='config',
                        default=None,
                        help='The directory to which config is saved.')

    args = parser.parse_args()

    # The current run time.
    script_time = time()

    subsPath = 'subs.xml'
    if args.config is not None:
        subsPath = f'{args.config}/{subsPath}'
    outlines = opml.parse(subsPath)

    if args.output is not None:
        args.output = Path(args.output).absolute()
        os.chdir(args.output)
    else:
        print('Must specify an ouput directory with -o')

    lastPath = 'last.txt'
    if args.config is not None:
        lastPath = f'{args.config}/{lastPath}'

    if not Path(lastPath).exists():
        with open(lastPath, 'w') as f:
            f.write(str(time()))
            print('Initialized a last.txt file with current timestamp.')
    else:
        with open(lastPath, 'r') as f:
            # The last run time.
            threshold_time = datetime.utcfromtimestamp(float(f.read()))

        # Overrule the time from which to download video if we've been asked to
        # keep videos since a certain number of days ago.
        if args.since is not None:
            threshold_time = datetime.fromtimestamp(script_time) - relativedelta(days=float(args.since))

        if args.retain is not None:
            # Find the videos in this directory which are older than the time
            # stamp since the last run and remove them.
            keep_time = datetime.fromtimestamp(script_time) - relativedelta(days=float(args.retain))
            for video in Path('.').glob('**/*.*'):
                if 'last.txt' in str(video):
                    continue
                modified_time = datetime.utcfromtimestamp(os.path.getmtime(video))
                if modified_time < keep_time:
                    print(f'Removing {str(video)}.')
                    video.unlink()

        urls = [outline.xmlUrl for outline in outlines[0]]

        videos = []
        for i, url in enumerate(urls):
            print(f'Parsing through channel {i + 1} of {len(urls)}', end='\r')
            feed = feedparser.parse(url)
            for item in feed['items']:
                video_time = datetime.fromtimestamp(mktime(item['published_parsed']))
                if video_time > threshold_time:
                    videos.append(item['link'])

        print(' ' * 100, end='\r')
        if len(videos) == 0:
            print('Sorry, no new video found')
            quit()
        else:
            print(f'{len(videos)} new videos found')

        ydl_opts = {'ignoreerrors': True, 'quiet': True, 'outtmpl': (args.output / Path('%(uploader)s', '%(title)s.%(ext)s')).as_posix()}

        with youtube_dl.YoutubeDL(ydl_opts) as ydl:
            ydl.download(videos)

        with open(lastPath, 'w') as f:
            f.write(str(script_time))