var worker;

function load() {
	init_worker();
	document.querySelector('#player').addEventListener('ended', function() {
		if (document.querySelector('#shuffle').checked) {
			ww_send_event('random_track', {});
		}
	});
}

function init_worker() {
	worker = new Worker('/static/scorchWorker.js');
	worker.onmessage = ww_onmessage;
	worker.events = {};
	worker.events['artist_albums'] = artist_albums_recv;
	worker.events['album_tracks'] = album_tracks_recv;
	worker.events['track'] = track_recv;
}

function ww_send_event(event_title, data) {
	worker.postMessage([event_title, data]);
}

function ww_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 (worker.events[event_title] === undefined) {
		console.log("Unknown socket event: " + event_title);
		return;
	}
	//console.log("Received `" + event_title + "` event with following data: " + JSON.stringify(data));
	worker.events[event_title](data);
}

/* 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,
	};
	ww_send_event('select_artist', data);
}

function select_album(select) {
	let data = {
		'artist': document.querySelector('#artistList').value, 
		'album': select.value,
	};
	ww_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'],
	};
	ww_send_event('select_track', data);
}