var urlParams = new URLSearchParams(window.location.search);
var path = window.location.pathname.split("/");
var loc = path[path.length - 1];
var url = "/timetable/" + loc;
var timetable = {};
var timeOffset = Number.parseInt(urlParams.get("timeOffset"));
var flashDelay = urlParams.has("flashDelay") ? Number.parseInt(urlParams.get("flashDelay")) : 500;
var flashStart = urlParams.has("flashStart") ? Number.parseInt(urlParams.get("flashStart")) : 5*60;
var flashElement = "counter";
var lastFlash = null;
var locale =  "de-DE";

var shortTime = new Intl.DateTimeFormat(locale, { timeStyle: "short" })

function setTimetable(tt) {
    timetable = tt;
    updateCounter();
}

function getShow(tt, when) {
    if (tt.shows == null) {
	return null;
    }

    for (let i = 0; i < timetable.shows.length; i++) {
	let show = tt.shows[i];
	let start = new Date(show.start);

	// Show has not yet started
	if (when < start.getTime())
	    return null;

	// No end
	if (show.end == null) {
	    return show;
	}

	// Has it ended?
	let end = new Date(show.end);
	if (when < end.getTime())
	    return show;
    }

    return null;
}

function getNextShow(tt, when) {
    if (tt.shows == null) {
	return null;
    }

    for (let i = 0; i < timetable.shows.length; i++) {
	let show = tt.shows[i];
	let start = new Date(show.start);

	// Return the first show that has not yet started
	if (when < start.getTime())
	    return show;
    }

    return null;
}

function stopFlash() {
    let elem = document.getElementById(flashElement);
    if (elem === null)
	return;

    elem.classList.remove("flash");
    lastFlash = null;
}

function doFlash(now) {
    let elem = document.getElementById(flashElement);
    if (elem === null)
	return;

    if (lastFlash === null) {
	lastFlash = now;
    }

    if (now - lastFlash >= flashDelay) {
	elem.classList.toggle("flash");
	lastFlash = now;
    }
}

function updateCounter() {
    let artistSpan = document.getElementById("artist");
    let valueSpan = document.getElementById("counter-value");
    let unitSpan = document.getElementById("counter-unit");

    if (artistSpan === null || valueSpan === null || unitSpan === null)
	return;

    let now = new Date();
    if (timeOffset > 0) {
	now = new Date(now.getTime() + timeOffset*60000);
    }

    let show = getShow(timetable, now.getTime());
    if (show == null) {
	show = getNextShow(timetable, now.getTime());
	if (show != null) {
	    let start = new Date(show.start);

	    artistSpan.textContent = "Next: " + show.name;
	    valueSpan.textContent = shortTime.format(start);
	} else {
	    artistSpan.textContent = "";
	}
	unitSpan.textContent = "";
	stopFlash();
	return;
    }

    let value = "";
    let unit = ""
    if (show.end != null) {
	let end = new Date(show.end);
	let sec = Math.round((end - now) / 1000);
	if (sec >= 60) {
	    value = Math.ceil(sec / 60).toString();
	    unit = "m";
	} else {
	    value = sec.toString();
	    unit = "s";
	}

	if (sec < flashStart)
	    doFlash(now);
	else
	    stopFlash();
    } else {
	stopFlash();
    }

    artistSpan.textContent = show.name;
    valueSpan.textContent = value;
    unitSpan.textContent = unit;
}
setInterval(updateCounter, 100);

function updateTimetable() {
    console.log("Updating timetable");
    fetch(url, { signal: AbortSignal.timeout(5000) })
	.then(res => res.json())
	.then(tt => setTimetable(tt))
	.catch(err => console.log(err));
}
setInterval(updateTimetable, 2*60*1000);

updateTimetable();