#!/usr/bin/env python3
# BCAO - BandCamp Automatic Organiser
# copyright 2018-2019 @LynnearSoftware@fedi.lynnesbian.space
# Licensed under the GPLv3: https://www.gnu.org/licenses/gpl-3.0.html#content
# input: a .zip from bandcamp
# output: it organises it, adds cover art, puts it in the right place...

import argparse
import os
import re
import sys
import tempfile
import shutil
from os import path
from base64 import b64encode
from zipfile import ZipFile
from pathlib import Path
from typing import Optional, List, Dict

import mutagen
from mutagen.flac import Picture, FLAC
from mutagen.oggvorbis import OggVorbis
from mutagen import id3

from PIL import Image

def log(message: str, importance: int = 0):
	if not args.quiet or importance > 0:
		print(message)

def die(message: str, code: int = 1):
	print(message)
	sys.exit(code)

def get_tag(mut_song: mutagen.FileType, tag: str) -> str:
	if tag == "track":
		tag = "tracknumber"
	tag = tag.replace("_", "")
	return sanitise(mut_song[tag][0] if type(mut_song[tag]) is list else mut_song[tag])

def has_cover(mut_song: mutagen.FileType):
	if type(mut_song) is OggVorbis:
		return "metadata_block_picture" in mut_song and len(mut_song["metadata_block_picture"]) != 0
	if type(mut_song) is FLAC:
		return len(mut_song.pictures) != 0
	raise Exception(f"what is {type(mut_song)}")

def sanitise(in_str: str) -> str:
	if args.sanitise:
		return re.sub(r"[?\\/:|*\"<>]", "_", in_str)
	return in_str

def parse_add_cover_images(value: str) -> str:
	if value not in ["n", "a", "w"]:
		raise argparse.ArgumentTypeError("Must be one of n, a, w")
	return value

parser = argparse.ArgumentParser(usage='%(prog)s zip [options]',
	description="Extracts the given zip file downloaded from Bandcamp and organises it.")
parser.add_argument('zip', help='The zip file to use.')
parser.add_argument('-c', '--add-cover-images', dest='process_cover', default='w', type=parse_add_cover_images,
	help="When to embed cover art into songs. Options: [n]ever, [a]lways, [w]hen necessary. Default: %(default)s")
parser.add_argument('-d', '--destination', dest='destination', default='/home/lynne/Music/Music/',
	help="The directory to organise the music into. Default: %(default)s")
parser.add_argument('-q', '--quiet', dest='quiet', action='store_true',
	help='Disable non-error output and assume default artist name.')
parser.add_argument('-u', '--unsanitised', dest='sanitise', action='store_false',
	help="Don't replace NTFS-unsafe characters with underscores. Not recommended.")
parser.add_argument('-t', '--threshold', dest='threshold', nargs=1, default=300,
	help="Maximum acceptable file size for cover art, in kilobytes. Default: %(default)s")

args = parser.parse_args()
# convert args.threshold to bytes
args.threshold *= 1024

if not path.exists(args.zip):
	die(f"Couldn't find {args.zip}.", 2)

log("Extracting...")
tmp_dir: tempfile.TemporaryDirectory = tempfile.TemporaryDirectory()
tmp: str = tmp_dir.name
cover: Optional[str] = None
song_names: List[str] = []

with ZipFile(args.zip, 'r') as zip_file:
	for file in zip_file.namelist():
		if re.match(r"^(.+ - ){2}\d{2,} .+\.(ogg|flac|alac|aiff|wav|mp3|opus|m4a|aac)$", file):
			# bandcamp zips contains songs with names formatted like "Album - Artist - 01 Song.mp3"
			# for example, "King Crimson - In the Wake of Poseidon - 02 Pictures of a City.ogg"
			# this regex should match only on those, and cut out (hopefully) all of the bonus material stuff, which shouldn't
			#  be added to the music folder (since i sync that to my phone, and "making of" videos are cool, but i don't
			#  have the space for it).
			song_names.append(file)
			zip_file.extract(file, tmp)
		elif cover is None and re.match(r"cover\.(jpe?g|png)", file):
			cover = file
			zip_file.extract(file, tmp)

# save the format of the songs (ogg, mp3, etc)
# we'll need this to know what metadata format we should write
song_format: str = path.splitext(song_names[0])[1][1:]

if args.process_cover != 'n':
	log("Resizing album art to embed in songs...")
	with Image.open(str(Path(tmp, cover))) as image:
		temp_cover: Path = Path(tmp, "cover-lq.jpg")

		if image.mode in ["RGBA", "P"]:
			# remove alpha channel
			image = image.convert("RGB")

		image.save(temp_cover, quality=85, optimize=True)
		image_smol = image

		while path.getsize(temp_cover) > args.threshold:
			# keep shrinking the image by 90% until it's less than {args.threshold} kilobytes
			ratio = 0.9

			if path.getsize(temp_cover) > args.threshold * 2:
				# if the file size of the cover is more than double the threshold, resize the cover image size by 80% instead
				ratio = 0.8

			image_smol = image_smol.resize([round(n * ratio) for n in image_smol.size])
			image_smol.save(temp_cover, quality=85, optimize=True)
			if image_smol.size[0] == 10:
				# something very bad has happened here
				die("Failed to resize image")

	# read the image file to get its raw data
	with open(temp_cover, 'r+b') as cover_file:
		data = cover_file.read()

	with Image.open(temp_cover) as image:
		if song_format == "ogg" or song_format == "flac":
			# i hate this
			embed_cover = Picture()
			embed_cover.data = data
			embed_cover.type = mutagen.id3.PictureType.COVER_FRONT
			embed_cover.mime = "image/jpeg"
			embed_cover.width = image.size[0]
			embed_cover.height = image.size[1]
			embed_cover.depth = image.bits
		else:
			log(f"Format {song_format} is not fully supported - cover images will not be modified", 1)

artists: List[str] = []
album: Optional[str] = None
songs: Dict[str, str] = {}
zeroes = min(len(song_names), 2)
first_loop: bool = True

for song in song_names:
	m = mutagen.File(Path(tmp, song))
	if first_loop:
		# the first item in the artists list should be the album artist
		artists.append(get_tag(m, "album_artist"))
		album = get_tag(m, "album")
		first_loop = False

	# add the song's artist(s) to the list
	map(lambda x: artists.append(sanitise(x)), m['artist'])
	songs[song] = f"{str(get_tag(m, 'track')).zfill(zeroes)} {get_tag(m, 'title')}.{song_format}"

	if args.process_cover == 'a' or (args.process_cover == 'w' and has_cover(m) is False):
		log("Embedding cover art...")
		# embed cover art
		if song_format == "ogg":
			m["metadata_block_picture"] = [b64encode(embed_cover.write()).decode("ascii")]
			m.save()
		elif song_format == "flac":
			m.clear_pictures()
			m.add_picture(embed_cover)
			m.save()

# remove duplicate artists
artists = list(dict.fromkeys(artists))

if len(artists) > 1 and "Various Artists" not in artists:
	artists.append("Various Artists")

artist: Optional[str] = None
while artist is None:
	log("Artist directory:")
	for i, artist_name in enumerate(artists):
		log(f"{i+1}) {artist_name}")
	log(f"{len(artists) + 1}) Custom...")

	choice = "1" if args.quiet else input("> ")
	if choice.isdecimal():
		choice = int(choice)
		if choice == len(artists) + 1:
			log("Enter the name to use:")
			artist = input("> ")
		else:
			try:
				artist = artists[choice - 1]
			except KeyError:
				log(f"Please choose a number between 1 and {len(artists) + 1}.")
	else:
		log(f"Please choose a number between 1 and {len(artists) + 1}")

destination: Path = Path(args.destination, artist, album)
log(f"Moving files to \"{destination}\"...")
os.makedirs(destination, exist_ok=True)

for source_name, dest_name in songs.items():
	shutil.move(Path(tmp, source_name), Path(destination, dest_name))
shutil.move(Path(tmp, cover), Path(destination, cover))

tmp_dir.cleanup()
log("Done!")