Scorch/static/scorch.js

var socket;

function load() {
	socket = init_websocket();
	document.querySelector('#player').addEventListener('ended', function() {
		if (document.querySelector('#shuffle').checked) {
			socket.send_event('random_track', {});
		}
	});
}

/* Websocket setup */
function init_websocket() {
	let socket = new WebSocket('wss://' + window.location.hostname + ws_uri);
	socket.send_event = send_event;
	socket.onmessage = onmessage;
	socket.onclose = onclose;
	socket.onerror = onerror;
	socket.events = {};
	socket.events['artist_albums'] = artist_albums_recv;
	socket.events['album_tracks'] = album_tracks_recv;
	socket.events['track'] = track_recv;
	return socket;
}

function send_event(event_title, data) {
	data = JSON.stringify({'event': event_title, 'data': data});
	if (this.readyState == 0) {
		console.log("Socket is still opening!");
		return;
	}
	log_debug_message('debug', "Sending `" + event_title + "` event with following data: " + JSON.stringify(data));
	this.send(data);
}

function onopen(event) {
	log_debug_message('debug', 'Websocket connected to server.');
}

function onmessage(event) {
	let data;
	let event_title;
	try {
		data = JSON.parse(event.data);
	} catch(err) {
		// not JSON
		console.log(err);
		console.log(event);
		throw new Error("Error decoding JSON");
		return;
	}

	if (!data.ok) {
		throw new Error("Socket error: event = " + event_title + ", error = " + data.error);
	}

	try {
		event_title = data.event;
		data = data.data;
	} catch(err) {
		// not proper event
		console.log(err);
		console.log(event);
		throw new Error("Event malformed");
		return;
	}

	if (socket.events[event_title] === undefined) {
		console.log("Unknown socket event: " + event_title);
		return;
	}
	log_debug_message('debug', "Received `" + event_title + "` event with following data: " + JSON.stringify(data));
	socket.events[event_title](data);
}

async function onclose(event) {
	log_debug_message('debug', 'Websocket lost connection to server.')
	if (event.wasClean) { return; } // no need to reconnect
	console.log(event);
	console.log('Websocket lost connection to server. Re-trying...');
	await sleep(3000);
	socket = init_websocket();
}

function sleep(ms) {
	return new Promise(resolve => setTimeout(resolve, ms));
}

function onerror(event) {
	log_debug_message('error', 'Websocket encountered an error.')
	console.log("Websocket error!")
	console.log(event);
}

/* Websocket receive */
function artist_albums_recv(data) {
	let albums_list = document.querySelector('#albumList');
	while (albums_list.firstChild) {
		albums_list.removeChild(albums_list.lastChild);
	}
	for (let album of data) {
		let option = document.createElement('option');
		option.value = album['album'];
		option.innerText = album['album'];
		albums_list.appendChild(option);
	}
}

function album_tracks_recv(data) {
	let track_list = document.querySelector('#trackList');
	while (track_list.firstChild) {
		track_list.removeChild(track_list.lastChild);
	}
	for (let track of data) {
		let option = document.createElement('option');
		option.value = track['title'];
		option.innerText = track['discnumber'] + '.' + track['tracknumber'] + ' - ' + track['title'];
		option.dataset['discnumber'] = track['discnumber']
		option.dataset['tracknumber'] = track['tracknumber']
		track_list.appendChild(option);
	}
}

function track_recv(data) {
	document.querySelector('#nowPlayingArtist').innerText = data['albumartist'];
	document.querySelector('#nowPlayingAlbum').innerText = data['album'];
	document.querySelector('#nowPlayingTitle').innerText = data['title'];
	document.title = 'Scorch | ' + data['artist'] + ' - ' + data['title'];
	let player = document.querySelector('#player');
	player.firstElementChild.src = data['url'];
	player.load();
	player.play();
	document.querySelector('#albumCover').firstChild.src = data['coverart'];
}

/* Websocket send */
function select_artist(select) {
	let data = {
		'artist': select.value,
	};
	socket.send_event('select_artist', data);
}

function select_album(select) {
	let data = {
		'artist': document.querySelector('#artistList').value, 
		'album': select.value,
	};
	socket.send_event('select_album', data);
}

function select_track(select) {
	let data = {
		'artist': document.querySelector('#artistList').value,
		'album': document.querySelector('#albumList').value,
		'discnumber': select.selectedOptions[0].dataset['discnumber'],
		'tracknumber': select.selectedOptions[0].dataset['tracknumber'],
	};
	socket.send_event('select_track', data);
}

/* DOM */
function show_debug(checkbox) {
	if (checkbox.checked) {
		document.querySelector('#debugLog').style.display = 'inherit';
	} else {
		document.querySelector('#debugLog').style.display = 'none';
	}
}

function log_debug_message(log_level, message) {
	let msg = new Date().toTimeString().replace(/ .*/, '') + ' ' + message;
	let li = document.createElement('li');
	li.className = log_level;
	li.textContent = msg;
	document.querySelector('#debugLog').appendChild(li);
}