#!/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

DEBUG = False


def cleanup_metadata_files(music_directory):
    files = glob.glob(os.path.join(music_directory, '*.json'))

    for file in files:
        os.remove(file)


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="https://music.youtube.com/playlist?list=1234",
                        nargs='?',
                        default=None,
                        type=str,
                        help="Playlist or Song URL to download.")

    parser.add_argument("-c",
                        "--cookies",
                        metavar="cookiefile.txt",
                        type=str,
                        help="Cookie file to use.")

    parser.add_argument("-o",
                        "--output",
                        metavar="output_directory",
                        type=str,
                        help="Output directory to use")

    parser.add_argument("-r",
                        "--retryFile",
                        metavar="jamos_failed_urls.txt",
                        default=None,
                        type=str,
                        help="Output directory to use")

    args = parser.parse_args()

    if args.retryFile and args.url:
        print("Cannot have url and retry flag!\n")
        parser.print_help()
        raise Exception()

    if not args.retryFile and not args.url:
        print("Must pass either a url or a retry file!\n")
        parser.print_help()
        raise Exception()

    return 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 remove_special_characters_for_filename(filename):
    special_chars = [
        ['-', ' '],
        ['(', ''],
        [')', ''],
        ['/', ' '],
        ['/', ' '],
        [' ', '_'],
        ["'", ''],
        ["&", 'and'],
        [chr(8217), ''],
        ['$', 's'],
        ['.', '']
    ]
    new_name = filename

    for char_set in special_chars:
        new_name = new_name.replace(char_set[0], char_set[1])

    return new_name.lower()


def move_file(file, metadata, output_directory):
    artist = remove_special_characters_for_filename(metadata['artist'])
    album = remove_special_characters_for_filename(metadata['album'])
    title = remove_special_characters_for_filename(metadata['title'])

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

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

    # 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, '{}_{}_{}.mp3'.format(artist,
                                                            album,
                                                            title)))


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

    file['name'] = metadata['title']
    file['artist'] = metadata['artist']
    file['album'] = metadata['album']
    file['year'] = metadata['year']

    file.save()


def get_song_metadata_from_json(json, counter):
    metadata = {
        'title': 'unknownsong',
        'artist': 'unknownartist',
        'album': 'unknownalbum',
        'year': 1999,
        'jamos_filename': 'jamos_unknwon_file_number_{}.mp3'.format(counter),
    }

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

        if ('album' in json.keys()) and (json['album'] is not None):
            metadata['album'] = json['album']

        if ('title' in json.keys()) and (json['title'] is not None):
            metadata['title'] = json['title']

        if ('release_date' in json.keys() and
                json['release_date'] is not None):
            metadata['year'] = format_youtube_date(json['release_date'])

        artist_for_filename = metadata['artist'].replace(' ', '_').lower()
        title_for_filename = metadata['title'].replace(' ', '_').lower()
        metadata['jamos_filename'] = '{}_{}.mp3'.format(artist_for_filename,
                                                        title_for_filename)

    except Exception as ex:
        print(ex)

    return metadata


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,
        'quiet': not DEBUG
    }

    return youtube_dl.YoutubeDL(audio_options)


def save_urls_from_playlist_to_file(filename, urls):
    try:
        f = open(filename, "a")
        for url in urls:
            f.writelines(url + '\n')
        f.close()
    except Exception as e:
        print(e)
        raise e


if __name__ == "__main__":
    try:
        args = get_command_line_options()
    except Exception as ex:
        sys.exit()

    music_directory = args.output or os.path.join(os.path.expanduser("~"),
                                                  "Music")
    cookies = args.cookies or os.path.join(os.path.expanduser("~"),
                                           "cookies.txt")

    # From some testing, if your playlist is public, you don't have to use a
    # cookie file. Youtube-dl doesn't break or throw if the file doesn't exist.
    ytdl = create_downloader(music_directory, cookies)

    urls = []

    if args.url:
        playlist_url = args.url

        print("Downloading urls...", end="")
        urls = get_video_urls_in_playlist(playlist_url, ytdl)
        print("Done.")
    elif args.retryFile:
        with open(args.retryFile) as retry_file:
            urls = retry_file.read().splitlines()

    failed_urls = []
    for url in urls:
        try:
            print("Downloading: {}...".format(url), end='')
            ytdl.extract_info(url, download=True)
            print("Done.")
        except Exception as ex:
            print(ex)
            print("Could not download: {}".format((url)))
            failed_urls.append(url)

    try:
        if len(failed_urls) > 1:
            print("Saving failed urls to txt file.")
            save_urls_from_playlist_to_file(
                os.path.join(music_directory, "jamos_failed_urls.txt"),
                failed_urls)
        elif args.retryFile:
            # Just because we don't have any failed urls in this run, doesn't
            # mean that we can get rid of the retry file. We'll only remove it
            # if it's been explicitly tried and we have no failed urls.

            # We've successfully downloaded all of the previously failed urls.
            # Delete the file
            os.remove(args.retryFile)
    except Exception as ex:
        print(ex)
        print("Saving failed urls to file failed! Printing failed urls:")
        for url in failed_urls:
            print(url)

    files = get_all_files(music_directory)

    counter = 1
    for f in files:
        try:
            print("Adding metadata to {} ...".format(f), end="")
            with open(f.replace('.mp3', '.info.json')) as json_file:
                json_data = json.load(json_file)
                metadata = get_song_metadata_from_json(json_data, counter)
                write_metadata_to_song_file(f, metadata)
                print("Done".format(f))
            print("Moving file...", end="")
            move_file(f, metadata, music_directory)
            print("Done", end="")
            counter += 1
        except Exception as e:
            # just gonna print this and move on to the next file.
            print(e)

    print("Cleaning up JSON files...", end='')
    cleanup_metadata_files(music_directory)
    print("Done.")