dwelling-radio/web/assets/js/main.js

const $ = id => document.getElementById(id);

const formatDuration = date => `${date.getUTCHours() > 0 ? date.getUTCHours() + ":" : ""}${date.getUTCMinutes()}:${date.getUTCSeconds().toString().padStart(2, "0")}`;
const formatStartAt = date => `${date.getHours().toString().padStart(2, "0")}:${date.getMinutes().toString().padStart(2, "0")}`;

let cursong_startat = null;
let cursong_duration_msec = 0;

async function updateStatus() {
	const resp = await fetch("/api/status");

	if (!resp.ok || 200 != resp.status) {
		$("radio-song").textContent =
			$("radio-duration-estimate").textContent =
				$("radio-duration").textContent = "";
		$("radio-listeners").textContent = "0";
		$("last-songs").lastChild.remove();
		return [-1, null];
	}

	const s = await resp.json();

	if (undefined != s.last_songs) {
		$("last-songs").lastChild.remove();
		$("last-songs").appendChild(document.createElement("tbody"));
		for (let i = 0; i < s.last_songs.length; ++i) {
			let row = $("last-songs").lastChild.insertRow();
			row.insertCell().appendChild(document.createTextNode(formatStartAt(new Date(s.last_songs[i].start_at))));
			row.insertCell().appendChild(document.createTextNode((s.last_songs[i].listeners == undefined ? "" : s.last_songs[i].listeners + "/") + (s.last_songs[i].peak_listeners == undefined ? "" : s.last_songs[i].peak_listeners)));
			row.insertCell().appendChild(document.createTextNode(`${s.last_songs[i].artist} - ${s.last_songs[i].title}`));
		}
	}

	if (undefined == s.current_song || undefined == s.current_song.duration_msec)
		return [-1, null];

	$("radio-song").textContent = `${s.current_song.artist} - ${s.current_song.title}`;
	$("radio-listeners").textContent = s.listeners;
	$("radio-duration").textContent = formatDuration(new Date(s.current_song.duration_msec));

	return [s.current_song.duration_msec, new Date(s.current_song.start_at)];
}

async function update() {
	if (null === cursong_startat)
		return -1;

	const estimate = (new Date()) - (new Date(cursong_startat));
	if (estimate >= cursong_duration_msec) {
		return 1;
	}

	$("radio-duration-estimate").textContent = `${formatDuration(new Date(estimate))} / `;
	return 0;
}

let update_interval_id = null;
async function interval() {
	switch (await update()) {
		case 1:
			[cursong_duration_msec, cursong_startat] = await updateStatus();
			break;
		case -1:
			clearInterval(update_interval_id);
			await new Promise(resolve => setTimeout(resolve, 5000));
			[cursong_duration_msec, cursong_startat] = await updateStatus();
			update_interval_id = setInterval(interval, 1000);
	}
}

updateStatus().then(r => [cursong_duration_msec, cursong_startat] = r);
update_interval_id = setInterval(interval, 1000);



const audio = document.getElementsByTagName("audio")[0];
audio.hidden = true;
const audio_src = audio.childNodes[0].src;

const volume = $("radio-volume");
volume.value = +(localStorage.getItem("volume") || 50);
audio.volume = volume.value / 100.0;
volume.addEventListener("input", e => {
	audio.volume = e.target.value / 100.0;
	localStorage.setItem("volume", e.target.value); });

$("player").style.display = $("player").firstChild.style.display = "flex";

$("radio-play").addEventListener("click", e => {
	audio.paused ? (audio.src = audio_src) && audio.play() : audio.src = "";
	e.target.style.backgroundImage = audio.paused ?
		"url(/assets/img/play.svg)" : "url(/assets/img/stop.svg)"; });