var socket;

function load() {
	socket = init_websocket();
}

/* 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['albums'] = albums_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;
	}
	this.send(data);
}

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;
	}
	socket.events[event_title](data);
}

async function onclose(event) {
	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) {
	console.log("Websocket error!")
	console.log(event);
}

/* Websocket receive */
function 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;
		option.innerText = album;
		albums_list.appendChild(option);
	}
}

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

/* DOM */