#!/usr/bin/env python3

# ===================================================
# Spotify playlist syncer using spotify-downloader
# ===================================================
# 
# Author: Prithu Goswami
# Email: prithugoswami524@gmail.com
# Date: 21 Sep 2018
#
# Description:
# This script syncs playlist from spotify using the spotify-downloader
# module written by ritiek [https://github.com/ritiek/spotify-downloader]
# Conifg file : ~/.config/playlist-syncer/config.json
# The config file is in json and is read to get a list of playlists to sync
# 
# Requirements:
# 'spotdl', 'unicode-slugify', 'spotipy'
#
# Example config file:
#
#
# {
#     "playlists": [
#         {
#             "name": "Today's Top Hits",
#             "id": "37i9dQZF1DXcBWIGoYBM5M",
#             "owner_id": "spotify",
#             "location": "/home/user/music/todays-top-hits/",
#             "snapshot_id": "<user does not need to bother with this",
#             "last_updated": "never"
#         },
#         {
#             "name": "Feel Good",
#             "id": "2BARfqxeupzZy3TWMnAaSw",
#             "owner_id": "Deby",
#             "location": "/home/user/music/feel-good/",
#             "snapshot_id": "<user does not need to bother with this",
#             "last_updated": "never"
#         },
#     ]
# }
#
# A new playlist entry is created by giving the `-a` option to the script
# followed by the id and a local path where the music will be downloaded
#
# Example:
# $ playlist-sync -a <playlist-id> <absolute-path-to-directory>


import json
import os 
import shlex
import subprocess
import sys

import spotipy
from slugify import slugify
from spotipy.oauth2 import SpotifyClientCredentials
from time import strftime


ok='{}[]()-_'
HOME=os.environ['HOME']
client_id='5a78b4a9902c4ae1b8cba38dade6acc8'
client_secret='884b0b01626b4e67888dada40ce49852'
config_path=HOME+'/.config/playlist-sync/config.json'
log_dir_path=HOME+'/.log/playlist-sync'

client_credentials_manager = SpotifyClientCredentials(client_id=client_id,
        client_secret=client_secret)
sp = spotipy.Spotify(client_credentials_manager=client_credentials_manager)
config={}

def create_config():
    ans = input("Config file does not exist. Create it? [y/n] ")
    if ans in "yY":
        os.mkdir(HOME+'/.config/playlist-sync')
        global config
        config={'playlists':[]}
        with open(config_path, 'w') as jsonfile:
            json.dump(config, jsonfile, indent=4)
        ans = input("\nWould you also like to add a playlist? [y/n] ")
        if ans in "yY":
            pl_id=input('\nPlaylist Id > ')
            pl_path=input('Playlist local path (absolute path) > ')
            add_playlist(pl_id, pl_path)
        else:
            print('\nYou can add a playlist by passing the `-a` option to the'
                    'script\n\nsyntax: $ playlist-sync -a <playlist-id> '
                    '<absolute-path-to-directory>')
            exit(0)
    else:
        exit(0)


def add_playlist(plid, path):
    try:
        pl=sp.user_playlist(' ', plid)
    except spotipy.client.SpotifyException:
        print('Err:Invalid Playlist Id')
        exit(1)

    playlist= {
        "name": pl['name'],
        "id": pl['id'],
        "location": path,
        "snapshot_id": ' ',
        "last_updated": 'never'
    }
    config['playlists'].append(playlist)
    with open(config_path, 'w') as jsonfile:
        json.dump(config, jsonfile, indent=4)

    print('Added playlist: {} \n'
          'Sync path: {}'.format(pl['name'], path))
    print('\nUpdated config file')
    if not os.path.exists(path):
        os.mkdir(path)
        print('Created directory: {}'.format(path))

def requires_update(playlist_data, playlist):
    return playlist_data['snapshot_id'] != playlist['snapshot_id']

def get_local_tracknames(playlist):
    tracks=set()
    for f in os.listdir(playlist['location']):
        if f.endswith("mp3"):
            tracks.add(f[:-4])
    return tracks

def get_need_to_download(playlist_data, playlist):
    """
    Return a set of urls to be downloaded that are not present in the current
    local playlist collection
    """
    sp_tracknames=set()
    loc_tracknames = get_local_tracknames(playlist)
    sp_tracks=[]
    for t in playlist_data['tracks']['items']:
        tr={
            'title':slugify(t['track']['name'], lower=False, spaces=True, ok=ok),
            'artist':slugify(t['track']['artists'][0]['name'], spaces=True, lower=False, ok=ok)
        }
        sp_track={
            'string':tr['artist']+' - '+tr['title'],
            'url':t['track']['external_urls']['spotify']
        }
        sp_tracks.append(sp_track)
        sp_tracknames.add(sp_track['string'])
    need_to_download = sp_tracknames-loc_tracknames
    for t in need_to_download:
        for track in sp_tracks:
            if t==track['string']:
                need_to_download.add(track['url'])
                #FIXME: If there are duplicates in the playlist remove them before proceeding
                need_to_download.remove(t)

    return need_to_download


def write_log(data):
    logname=strftime('%c').replace(' ','-')+'sc.log'
    with open(log_dir_path+'/'+logname, 'w') as l:
        l.write(data)

def update_m3u(playlist_data, playlist):
    m3uloc=playlist['location']+slugify(playlist_data['name'], ok=ok)+'.m3u8'
    with open(m3uloc, 'w') as m3ufile:
        for t in playlist_data['tracks']['items']:
            tr={
                'title':slugify(t['track']['name'], lower=False, spaces=True, ok=ok),
                'artist':slugify(t['track']['artists'][0]['name'], spaces=True, lower=False, ok=ok)
            }
            track_string=tr['artist']+' - '+tr['title']+'.mp3\n'
            m3ufile.write(track_string)


def update_playlist(playlist_data, playlist):
    print("Updating Playlist: " + playlist['name'] + "\n")

    track_urls=get_need_to_download(playlist_data, playlist)

    with open("/tmp/spotdllist.txt", 'w') as f:
        for a in track_urls:
            f.write(a+'\n')
    print('Written files to /tmp/spotdllist.txt')

    print('Track links to downalod:')
    for m in track_urls:
        print(m)

    command=('spotdl --list /tmp/spotdllist.txt -f {} --trim-silence --overwrite skip'
             .format(playlist['location']))
    args=shlex.split(command)
    print('\nCalling spotdl')
    p = subprocess.Popen(args, universal_newlines=True)
    p_out, p_err = p.communicate()
    if p.returncode!=0:
        d = "-----STDOUT------\n"+p_out+'\n'*3+"-----STDERR------\n"+p_err
        write_log(d)
        print('Error occured, log written')
        return
    else:
        update_m3u(playlist_data, playlist)
        print('Updated the m3u playlist')
        i=0
        for pl in config['playlists']:
            if pl['id']==playlist['id']:
                config['playlists'][i]['snapshot_id']=playlist_data['snapshot_id']
                config['playlists'][i]['last_updated']=strftime('%c')
            i+=1

        with open(config_path, 'w') as jsonfile:
            json.dump(config, jsonfile, indent=4)
        print('updated config')
        return


if not os.path.exists(config_path):
    create_config()
else:
    with open(config_path, 'r') as jsonfile:
        config = json.load(jsonfile)

playlists=config['playlists']
if not playlists:
    print('There are no playlists to process')
    print('Add playlist by passing the `-a` option.\n\nsyntax: '
          '$ playlist-sync -a <playlist-id> <absolute-path-to-directory>')
    exit(0)


if len(sys.argv)>1:
    if sys.argv[1]=='-a':
        add_id=sys.argv[2]
        add_id_path=sys.argv[3]
        if add_id_path[-1] != '/':
            add_id_path+='/'
        add_playlist(add_id, add_id_path)
        exit(0)

for playlist in playlists:
    playlist_data=sp.user_playlist(' ', playlist_id=playlist['id'])
    if requires_update(playlist_data, playlist):
        update_playlist(playlist_data, playlist)