#! /usr/bin/env python3
# -*- coding: utf-8 -*-
# vim:fenc=utf-8:ft=python
#
# Bad Witch
# Copyright © 2020 Vintage Salt <rehashedsalt@cock.li>
#
# Distributed under terms of the MIT license.
#

from appdirs import AppDirs
from pathlib import Path
import argparse
import eyed3
import json
import logging
import math
import pathlib
import sys
import youtube_dl

class Library:
    # A thing full of albums
    def __init__(self, file, albums={}):
        self.albums = albums
        self.file = file

    # Load from file
    def load(self):
        try:
            with open(self.file, 'r+') as libfd:
                libfd.seek(0)
                self.albums = json.load(libfd)
        except FileNotFoundError:
            logging.debug('Could not find library, loading empty')
            self.albums = {}
        return

    # Save to file
    def save(self):
        with open(self.file, 'w+') as libfd:
            libfd.seek(0)
            json.dump(self.albums, libfd, indent='\t')
        return

    def validate(self):
        self.load()
        for album, albumcontent in self.albums.items():
            for song, songcontent in albumcontent.items():
                for field in ['track', 'artist', 'source']:
                    if field not in songcontent:
                        raise Exception('Song is missing required field', song, field)

    # Download library
    def download(self, targetalbum=None):
        if targetalbum is not None:
            print('Downloading album: ' + album)
        else:
            print('Downloading entire library')
        for album, albumcontent in self.albums.items():
            # Skip albums that don't match our criterea
            if targetalbum is not None and not album == targetalbum:
                logging.debug('Skipping album ' + album)
                continue
            # Get albumartist
            # Sets to Various Artists if multiple
            albumartist=''
            for song, songcontent in albumcontent.items():
                if albumartist == '':
                    albumartist = songcontent['artist']
                elif albumartist != songcontent['artist']:
                    albumartist = 'Various Artists'
                    break
            destpath = (Path.home() / 'Music' / albumartist / album)
            Path(destpath).mkdir(parents=True, exist_ok=True)
            # Actually download and tag songs
            for song, songcontent in albumcontent.items():
                try:
                    zeroes = int(math.log10(len(albumcontent)) + 1)
                    filename = str(songcontent['track']).zfill(zeroes) + ' - ' + song
                    destfile = str(destpath / filename) + '.%(ext)s'
                    logging.debug('Saving to: ' + destfile)
                    # See if we already have  it
                    if Path(str(destpath / filename) + '.mp3').exists():
                        # Skip downloading
                        logging.info('Already have song: ' + song)
                    else:
                        # Download the song
                        ytdl_opts = {
                                'format': 'bestaudio',
                                'outtmpl': destfile,
                                'playlist_items': 1,
                                'quiet': True,
                                'writethumbnail': True,
                                'postprocessors': [{
                                    'key': 'FFmpegExtractAudio',
                                    'preferredcodec': 'mp3',
                                    'preferredquality': '192'
                                    },{
                                    'key': 'EmbedThumbnail'
                                    }]
                                }
                        with youtube_dl.YoutubeDL(ytdl_opts) as ydl:
                            ydl.download([songcontent['source']])
                        print('Downloaded song: ' + song)
                    # Add tags
                    logging.debug('Adding tags')
                    resultfile = eyed3.load(str(destpath / filename) + '.mp3')
                    resultfile.tag.album_artist = albumartist
                    resultfile.tag.artist = songcontent['artist']
                    resultfile.tag.album = album
                    resultfile.tag.title = song
                    resultfile.tag.track_num = songcontent['track']
                    resultfile.tag.save()
                except (KeyboardInterrupt, EOFError):
                    logging.debug('Interrupt received, exiting')

class BadWitch:
    # Our program
    def __init__(self):
        # Flags and arguments
        self.argparser = argparse.ArgumentParser(
                description='Manage a declarative music library through YouTube scraping')
        self.argparser.add_argument('-l', '--library', metavar='FILE', nargs='?',
                help='Override default library file with this one')
        self.argparser.add_argument('-v', '--verbose', action='store_true',
                help='Show more status messages')
        self.argparser.add_argument('-d', '--debug', action='store_true',
                help='Show even more status messages')
        self.argparser.add_argument('action', metavar='action', nargs='?',
                choices=['download', 'edit', 'list'],
                help='Action to perform on the library')
        # Set up appdirs
        self.dirs = AppDirs('badwitch', 'rehashedsalt')
        Path(self.dirs.user_data_dir).mkdir(parents=True, exist_ok=True)

    def execute(self):
        self.args = self.argparser.parse_args() 
        # Parse flags
        if self.args.debug:
            logging.basicConfig(level=logging.DEBUG)
        elif self.args.verbose:
            logging.basicConfig(level=logging.INFO)
        # Initialize library
        libfile = self.args.library or self.dirs.user_data_dir + '/lib.json'
        lib = Library(file=libfile)
        lib.load()
        lib.validate()
        # Perform action
        if self.args.action == 'download':
            lib.download()
            return
        elif self.args.action == 'edit':
            print('Bad Witch interactive $ibrary editor')
            print('^C to abort, ^D to finish changes')
            print('Loaded library ' + lib.file)
            try:
                while True:
                    in_album = input('\tAlbum: ')
                    auto_artist = input('\tArtist (leave blank to assign per song): ')
                    auto_track = int(input('\tStarting track number (leave blank to assign per song): ') or -1)
                    if in_album not in lib.albums:
                        lib.albums[in_album] = {}
                    else:
                        print('\tLoaded existing album')
                    album = lib.albums[in_album]
                    try:
                        while True:
                            in_song = input('\t\tSong title: ')
                            if auto_artist is not '':
                                in_artist = auto_artist
                            else:
                                in_artist = input('\t\tArtist: ')
                            if auto_track is not -1:
                                in_track = auto_track
                                auto_track += 1
                            else:
                                in_track = input('\t\tTrack number: ')
                            in_source = input('\t\tSource URL: ')
                            # Only assign values if we gave them
                            if in_song not in album:
                                album[in_song] = {}
                            else:
                                print('\t\tLoaded existing song')
                            song = album[in_song]
                            if in_track is not '': song['track'] = int(in_track)
                            if in_artist is not '': song['artist'] = in_artist
                            if in_source is not '': song['source'] = in_source
                            # Bail if song is bad
                            for field in ['track', 'artist', 'source']:
                                if field not in song:
                                    print('\t\tError: Critical field is empty: ' + field)
                                    continue
                    except KeyboardInterrupt:
                        print('\n\t\tAborting, changes were not saved')
                    except EOFError:
                        album[in_song] = song
                        print('\n\t\tChanges cached, ^D again to save')
                    lib.albums[in_album] = album
                    lib.save()
            except KeyboardInterrupt:
                print('\n\tAborting, changes were not saved')
            except EOFError:
                lib.save()
                print('\n\tSaving changes')
            print('Closing library')
        elif self.args.action == 'list':
            for album, albumcontent in lib.albums.items():
                print(album)
                for song, songcontent in albumcontent.items():
                    print(str(songcontent['track'])
                            + ' - ' + song
                            + ' by ' + songcontent['artist'])
            return

badwitch = BadWitch()
badwitch.execute()