Musare/backend/logic/stations.js

'use strict';

const cache = require('./cache');
const db = require('./db');
const io = require('./io');
const utils = require('./utils');
const songs = require('./songs');
const notifications = require('./notifications');
const async = require('async');
let skipTimeout = null;

//TEMP
cache.sub('station.pause', (stationId) => {
	notifications.remove(`stations.nextSong?id=${stationId}`);
});

cache.sub('station.resume', (stationId) => {
	module.exports.getStation(stationId, (err, station) => {})
});

module.exports = {

	init: function(cb) {
		let _this = this;
		//TODO Add async waterfall
		db.models.station.find({}, (err, stations) => {
			if (!err) {
				stations.forEach((station) => {
					console.info("Initializing Station: " + station._id);
					_this.initializeStation(station);
				});
				cb();
			}
		});
	},

	initializeStation: function(_station) {
		let _this = this;
		_this.getStation(_station._id, (err, station) => {
			if (!err) {
				if (station) {
					let notification = notifications.subscribe(`stations.nextSong?id=${station._id}`, () => {
						console.log("NOTIFICATION!!!");
						_this.getStation(_station._id, (err, station) => {
							if (station) {
								// notify all the sockets on this station to go to the next song
								async.waterfall([

									(next) => {
										if (station.playlist.length > 0) {
											function func() {
												if (station.currentSongIndex < station.playlist.length - 1) {
													station.currentSongIndex++;
													songs.getSong(station.playlist[station.currentSongIndex], (err, song) => {
														if (!err) {
															let $set = {};

															$set.currentSong = {
																_id: song._id,
																title: song.title,
																artists: song.artists,
																duration: song.duration,
																likes: song.likes,
																dislikes: song.dislikes,
																skipDuration: song.skipDuration,
																thumbnail: song.thumbnail
															};
															$set.startedAt = Date.now();
															$set.timePaused = 0;
															next(null, $set);
														} else {
															db.models.station.update({_id: station._id}, {$inc: {currentSongIndex: 1}}, (err) => {
																_this.updateStation(station._id, () => {
																	func();
																});
															});
														}
													});
												} else {
													db.models.station.update({_id: station._id}, {$set: {currentSongIndex: 0}}, (err) => {
														_this.updateStation(station._id, (err, station) => {
															console.log(12345678, err, station);
															_this.calculateSongForStation(station, (err, newPlaylist) => {
																console.log('New playlist: ', newPlaylist);
																if (!err) {
																	songs.getSong(newPlaylist[0], (err, song) => {
																		let $set = {};
																		if (song) {
																			$set.currentSong = {
																				_id: song._id,
																				title: song.title,
																				artists: song.artists,
																				duration: song.duration,
																				likes: song.likes,
																				dislikes: song.dislikes,
																				skipDuration: song.skipDuration,
																				thumbnail: song.thumbnail
																			};
																			station.playlist = newPlaylist;
																		} else {
																			$set.currentSong = _this.defaultSong;
																		}
																		$set.startedAt = Date.now();
																		$set.timePaused = 0;
																		next(null, $set);
																	});
																} else {
																	let $set = {};
																	$set.currentSong = _this.defaultSong;
																	$set.startedAt = Date.now();
																	$set.timePaused = 0;
																	next(null, $set);
																}
															})
														});
													});
												}
											}
											func();
										} else {
											_this.calculateSongForStation(station, (err, playlist) => {
												if (!err && playlist.length === 0) {
													let $set = {};
													$set.currentSongIndex = 0;
													$set.currentSong = _this.defaultSong;
													$set.startedAt = Date.now();
													$set.timePaused = 0;
													next(null, $set);
												} else {
													songs.getSong(playlist[0], (err, song) => {
														let $set = {};
														if (!err) {
															$set.currentSong = {
																_id: song._id,
																title: song.title,
																artists: song.artists,
																duration: song.duration,
																likes: song.likes,
																dislikes: song.dislikes,
																skipDuration: song.skipDuration,
																thumbnail: song.thumbnail
															};
														} else {
															$set.currentSong = _this.defaultSong;
														}
														$set.currentSongIndex = 0;
														$set.startedAt = Date.now();
														$set.timePaused = 0;
														next(null, $set);
													});
												}
											});
										}
									},

									($set, next) => {
										db.models.station.update({_id: station._id}, {$set}, (err) => {
											_this.updateStation(station._id, (err, station) => {
												console.log(err, station);
												next(null, station);
											});
										});
									},


								], (err, station) => {
									console.log(err, station);
									io.io.to(`station.${station._id}`).emit("event:songs.next", {
										currentSong: station.currentSong,
										startedAt: station.startedAt,
										paused: station.paused,
										timePaused: 0
									});
									utils.socketsJoinSongRoom(io.io.to(`station.${station._id}`).sockets, `song.${station.currentSong._id}`);
									// schedule a notification to be dispatched when the next song ends
									console.log("NEXT SONG!!!");
									if (!station.paused) {
										notifications.schedule(`stations.nextSong?id=${station._id}`, station.currentSong.duration * 1000);
									}
								});
							}
							// the station doesn't exist anymore, unsubscribe from it
							else {
								notifications.remove(notification);
							}
						});
					}, true);
					if (!station.paused) {
						/*if (!station.startedAt) {
							station.startedAt = Date.now();
							station.timePaused = 0;
							cache.hset('stations', stationId, station);
						}*/
						let timeLeft = ((station.currentSong.duration * 1000) - (Date.now() - station.startedAt - station.timePaused));
						if (isNaN(timeLeft)) timeLeft = -1;
						if (station.currentSong.duration * 1000 < timeLeft || timeLeft < 0) {
							console.log("Test");
							notifications.schedule(`stations.nextSong?id=${station._id}`, 1);
						} else {
							notifications.schedule(`stations.nextSong?id=${station._id}`, timeLeft);
						}
					} else {
						notifications.unschedule(`stations.nextSong?id${station._id}`);
					}
				}
			}
		});
	},

	calculateSongForStation: function(station, cb) {
		let _this = this;
		let songList = [];
		async.waterfall([

			(next) => {
				let genresDone = [];
				station.genres.forEach((genre) => {
					db.models.song.find({genres: genre}, (err, songs) => {
						if (!err) {
							songs.forEach((song) => {
								if (songList.indexOf(song._id) === -1) songList.push(song._id);
							});
						}
						genresDone.push(genre);
						if (genresDone.length === station.genres.length) {
							next();
						}
					});
				});
			},

			(next) => {
				let playlist = [];
				songList.forEach(function(songId) {
					if(station.playlist.indexOf(songId) === -1) playlist.push(songId);
				});
				station.playlist.filter((songId) => {
					if (songList.indexOf(songId) !== -1) playlist.push(songId);
				});
				db.models.station.update({_id: station._id}, {$set: {playlist: playlist}}, (err) => {
					_this.updateStation(station._id, () => {
						next(err, playlist);
					});
				});
			}

		], (err, newPlaylist) => {
			cb(err, newPlaylist);
		});
	},

	// Attempts to get the station from Redis. If it's not in Redis, get it from Mongo and add it to Redis.
	getStation: function(stationId, cb) {
		async.waterfall([

			(next) => {
				cache.hget('stations', stationId, next);
			},

			(station, next) => {
				if (station) return next(true, station);

				db.models.station.findOne({ _id: stationId }, next);
			},

			(station, next) => {
				if (station) {
					station = cache.schemas.station(station);
					cache.hset('stations', stationId, station);
					next(true, station);
				} else next('Station not found.');
			},

		], (err, station) => {
			if (err && err !== true) cb(err);

			cb(null, station);
		});
	},

	updateStation: (stationId, cb) => {
		async.waterfall([

			(next) => {
				db.models.station.findOne({ _id: stationId }, next);
			},

			(station, next) => {
				if (!station) return next('Station not found.');

				cache.hset('stations', stationId, station, (err) => {
					if (err) return next(err);
					next(null, station);
				});
			}

		], (err, station) => {
			if (err && err !== true) cb(err);

			cb(null, station);
		});
	},

	defaultSong: {
		_id: '60ItHLz5WEA',
		title: 'Faded',
		artists: ['Alan Walker'],
		duration: 212,
		skipDuration: 0,
		thumbnail: 'https://i.scdn.co/image/2ddde58427f632037093857ebb71a67ddbdec34b'
	}

};