import os
import sys
import json
import yt_dlp


def download_playlist_for_cd(playlist_url: str, output_folder: str = "cd_audio"):
    """Downloads YouTube audio directly into 44.1kHz 16-bit WAV files

    ideal for burning directly to Audio CDs without secondary re-encoding loss.
    """
    if not os.path.exists(output_folder):
        os.makedirs(output_folder)

    ydl_opts = {
        # Grab best audio stream available
        "format": "bestaudio/best",
        # Prefix with track index (01, 02...) so CD track order matches playlist order
        "outtmpl": os.path.join(output_folder, "%(playlist_index)s - %(title)s.%(ext)s"),
        "postprocessors": [
            {
                "key": "FFmpegExtractAudio",
                "preferredcodec": "wav",  # Lossless format native to CD Burning
            }
        ],
        # Enforce Red Book CD Standard audio resampling (44.1 kHz)
        "postprocessor_args": [
            "-ar", "44100",  # Set sample rate to 44.1 kHz (CD Standard)
            "-ac", "2",      # Force 2 channels (Stereo)
        ],
        "ignoreerrors": True,
    }

    print(f"Downloading audio optimized for CD burning: {playlist_url}")
    with yt_dlp.YoutubeDL(ydl_opts) as ydl:
        ydl.download([playlist_url])

    print("\nDownload complete! Import these .wav files directly into your CD burner.")



def download_single_video(url, song_num, artist, title):
    output_folder = "cd_audio"

    if not os.path.exists(output_folder):
        os.makedirs(output_folder)

    ytdl_opts = {
        "format": "bestaudio/best",
        "noplaylist": True,
        "outtmpl": os.path.join(output_folder, f"{song_num} - {artist} - {title}.%(ext)s"),
        "postprocessors": [
            {
                "key": "FFmpegExtractAudio",
                "preferredcodec": "wav",
            }
        ],
        "postprocessor_args": [
            "-ar", "44100",  # Set sample rate to 44.1 kHz (CD Standard)
            "-ac", "2",      # Force 2 channels (Stereo)
            "-metadata", f"artist={artist}",
            "-metadata", f"title={title}",
        ],
        "ignoreerrors": True,
    }

    with yt_dlp.YoutubeDL(ytdl_opts) as ytdl:
        ytdl.download([url])


def parse_file(filename):

    class Track:
        def __init__(self, track: int, title: str, url: str):
            self.track = track
            self.title = title
            self.url = url
    
    class Album:
        def __init__(self, artist: str, album: str):
            self.artist = artist
            self.album = album
            self.tracks = []
        def add_track(self, track: Track):
            self.tracks.append(track)
    
    with open(filename, "r") as file:
        data = json.load(file)

    
    albums = []

    for album in data:

        try:
            new_album = Album(
                album["artist"],
                album["album"])
            for video in album["tracks"]:
                new_album.add_track(Track(
                    video["track"],
                    video["title"],
                    video["url"]
                ))
        except KeyError as e:
            print(e)
            continue

        albums.append(new_album)

    return albums




if __name__ == "__main__":

    if len(sys.argv) == 1:
        url = input("Enter YouTube playlist URL: ").strip()
        if url:
            download_playlist_for_cd(url)

    else:
        data = parse_file(" ".join(sys.argv[1:]))
        for album in data:
            print(f"Band: {album.artist}")
            print(f"Album: {album.album}")

            for video in album.tracks:
                print(f"\tTrack {video.track}: {video.title}")

                if album.album == "Even In Arcadia":
                    download_single_video(
                        video.url,
                        video.track,
                        f"{album.artist} - {album.album}",
                        video.title
                    )