import os
import sys
import json
import yt_dlp


g_OUTPUT_FOLDER = "cd_audio"



def generate_ytdl_opts(outtmpl: str, metadata_artist: str = "", metadata_title: str = ""):
	return {
		"format": "bestaudio/best",
		"noplaylist": True,
		"outtmpl": outtmpl,
		"postprocessors": [
			{
				"key": "FFmpegExtractAudio",
				"preferredcodec": "wav",
			}
		],
		"postprocessor_args": [
			"-ar", "44100",
			"-ac", "2",
			"-metadata", f"artist={metadata_artist}",
			"-metadata", f"title={metadata_title}",
		],
		"ignoreerrors": True,
	}



def download_playlist_for_cd(playlist_url: str):
	ytdl_opts = generate_ytdl_opts(
		os.path.join(g_OUTPUT_FOLDER, "%(playlist_index)s - %(title)s.%(ext)s")
	)

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

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



def download_single_video(url, song_num, artist, title):

	ytdl_opts = generate_ytdl_opts(
		os.path.join(g_OUTPUT_FOLDER, f"{song_num} - {artist} - {title}.%(ext)s"),
		artist, title
	)

	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



def print_help():
	print("-h				print help and exit")
	print("-f <filename>	select a file (required)")
	print("-a				download all")
	print("-d <album>		download a specific album")


def parse_args(argv):

	class Ret:
		file = None
		downloads = None
	ret = Ret()

	cache_arg_count = len(argv)
	arg_idx = 1

	while arg_idx < cache_arg_count:

		if argv[arg_idx] == "-h":
			print_help()
			exit(1)

		elif argv[arg_idx] == "-f":
			if arg_idx + 1 >= cache_arg_count:
				raise ValueError("-f <filename> - is missing the filename")

			ret.file = argv[arg_idx + 1]

			arg_idx += 2
			continue

		elif argv[arg_idx] == "-a":

			if ret.downloads != None:
				raise ValueError("Cannot use -a twice, or in combination with -d")

			ret.downloads = ""

			arg_idx += 1
			continue

		elif argv[arg_idx] == "-d":

			if ret.downloads != None:
				raise ValueError("Cannot use -d twice, or in combination with -a")

			if arg_idx + 1 >= cache_arg_count:
				raise ValueError("-d <album> - is missing the album name")

			ret.downloads = argv[arg_idx + 1]

			arg_idx += 2
			continue

		else:
			print_help()
			exit(2)

	return ret




if __name__ == "__main__":

	config = parse_args(sys.argv)

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


	data = parse_file(config.file)


	for album in data:

		if not (config.downloads == "" or config.downloads == album.album):
			continue

		print(f"Band: {album.artist}")
		print(f"Album: {album.album}")

		for video in album.tracks:
			print(f"\tTrack {video.track}: {video.title}")
			download_single_video(
				video.url,
				video.track,
				f"{album.artist} - {album.album}",
				video.title
			)