#!/usr/bin/env python3
import argparse
import datetime
import glob
import json
import music_tag
import os
from pathlib import Path
import sys
import youtube_dl



def download_song(song_url, ytdl):
    """
    Download a song using youtube url and song title
    """
    return ytdl.extract_info(song_url, download=True)


def format_youtube_date(date):
    default = "Unknown Year"
    try:
        fmt = "%Y%m%d"
        d = datetime.datetime.strptime(date, fmt)
        return d.year
    except Exception as ex:
        print(ex)

    return default


def get_all_files(directory):
    things = glob.glob(os.path.join(directory, '*.mp3'))

    files = []

    for thing in things:
        if os.path.isfile(thing):
            files.append(thing)

    return files


def get_command_line_options():
    parser = argparse.ArgumentParser(description="Download songs from YouTube Music")
    parser.add_argument("url", metavar="string", type=str, help="Playlist or Song URL to download")
    parser.add_argument("-c", "--cookies", metavar="string", type=str, help="Cookie file to use.")
    parser.add_argument("-o", "--output", metavar="string", type=str, help="Output directory to use")

    return parser.parse_args()


# TODO: switch command line args to argparse
def get_playlist_url():
    return sys.argv[1]


def get_video_urls_in_playlist(playlist_url, ytdl):
    videos = ytdl.extract_info(playlist_url, download=False)

    urls = []
    for vid in videos['entries']:
        if 'webpage_url' in vid.keys() and vid['webpage_url'] is not None:
            urls.append(vid['webpage_url'])

    return urls


def move_file(file, metadata, output_directory):
    # TODO: Pass a jamos specific metadata object/dict
    # Then we can do this validation all at once

    artist = 'unknownartist'
    album = 'unknownalbum'
    title = 'unknownsong'

    if ('artist' in metadata.keys()) and (metadata['artist'] is not None):
        if len(metadata['artist'].split(',')) > 1:
            # If there are multiple artists, pick the first one
            # NOTE: This may break if the artist has a comma in their name
            artist = metadata['artist'].split(',')[0].replace(' ', '_').lower()
        else:
            artist = metadata['artist'].replace(' ', '_').lower()

    if ('album' in metadata.keys()) and (metadata['album'] is not None):
        album = metadata['album'].replace(' ', '_').lower()

    if ('title' in metadata.keys()) and (metadata['title'] is not None):
        title = metadata['title'].replace(' ', '_').replace('/', '').lower()

    final_directory = os.path.join(
        output_directory,
        artist,
        album)

    Path(final_directory).mkdir(parents=True, exist_ok=True)

    # TODO: Include album title in filename
    # TODO: Research converting to mp3 instead of just naming it such.
    # TODO: Research better file formats over mp3?
    os.rename(
        file,
        os.path.join(final_directory, artist + '_' + title + '.mp3'))


def write_metadata_to_song_file(file, metadata):
    f = music_tag.load_file(file)

    artist = 'unknownartist'
    album = 'unknownalbum'
    title = 'unknownsong'
    year = 9999

    if ('artist' in metadata.keys()) and (metadata['artist'] is not None):
        if len(metadata['artist'].split(',')) > 1:
            # If there are multiple artists, pick the first one
            # NOTE: This may break if the artist has a comma in their name
            artist = metadata['artist'].split(',')[0].replace(' ', '_').lower()
        else:
            artist = metadata['artist'].replace(' ', '_').lower()

        artist = artist.replace('&', 'and')

    if ('album' in metadata.keys()) and (metadata['album'] is not None):
        album = metadata['album'].replace(' ', '_').lower()

    if ('title' in metadata.keys()) and (metadata['title'] is not None):
        title = metadata['title'].replace(' ', '_').lower()

    if ('release_date' in metadata.keys()):
        year = format_youtube_date(metadata['release_date'])

    f['name'] = title
    f['artist'] = artist
    f['album'] = album
    f['year'] = year

    f.save()


def create_downloader(music_directory, cookies):
    audio_options = {
            'format': 'mp3/bestaudio/best',
            'cookiefile': cookies,
            'outtmpl': music_directory + '%(title)s.%(ext)s',
            'postprocessors': [
                {
                    'key': 'FFmpegExtractAudio',
                    'preferredcodec': 'mp3',
                    'preferredquality': '192',
                },
                {'key': 'FFmpegMetadata'},
            ],
            'writeinfojson': True
        }

    return youtube_dl.YoutubeDL(audio_options)


if __name__ == "__main__":
    args = get_command_line_options()

    # Get the playlist url from the command line
    playlist_url = args.url

    music_directory = args.output or "~/Music"
    cookies = args.cookies or "~/cookies.txt"

    ytdl = create_downloader(music_directory, cookies)

    # TODO: Save urls to file so we can start in the
    # middle of the playlist if needed
    urls = get_video_urls_in_playlist(playlist_url, ytdl)

    for url in urls:
        try:
            download_song(url, ytdl)
        except Exception as ex:
            # TODO: Handle this better
            print(ex)

    files = get_all_files(music_directory)

    for f in files:
        json_data = None
        with open(f.replace('.mp3', '.info.json')) as json_file:
            json_data = json.load(json_file)
            write_metadata_to_song_file(f, json_data)
        move_file(f, json_data, music_directory)