window.addEventListener("error", evt => {
	console.error(evt);
	alert("Error: " + evt.message + " -- " + evt.filename + ":" + evt.lineno);
});

window.addEventListener("unhandledrejection", evt => {
	console.error(evt);
	alert("Unhandled rejection: " + evt.reason.toString());
});

async function api(method, path, body = null) {
	let options = {method};
	if (body != null) {
		options.body = JSON.stringify(body);
	}

	let json;
	let resp = await fetch("/api/" + path, options).then(r => r.text());
	json = JSON.parse(resp);

	return json;
}

function html(name, attrs, children) {
	if (!(children instanceof Array)) {
		children = [children];
	}

	if (name == "text") {
		return document.createTextNode(attrs);
	}

	let el = document.createElement(name);
	for (let key in attrs) {
		if (!attrs.hasOwnProperty(key)) {
			continue;
		}

		el.setAttribute(key, attrs[key]);
	}

	for (let child of children) {
		if (typeof child == "string") {
			el.appendChild(document.createTextNode(child));
		} else {
			el.appendChild(child);
		}
	}

	return el;
}

function clearElement(el) {
	while (el.firstChild) {
		el.removeChild(el.firstChild);
	}
}

function renderToElement(el, children) {
	if (!(children instanceof Array)) {
		children = [children];
	}

	clearElement(el);
	for (let child of children) {
		el.appendChild(child);
	}
}

function debounce(func) {
	let f = function() {
		if (f.waiting) {
			f.args = arguments;
			return;
		}

		f.args = null;
		f.waiting = true;
		func.apply(null, arguments).then(() => {
			f.waiting = false;
			if (f.args != null) {
				f.apply(null, f.args);
			}
		});
	}

	f.args = null;
	f.waiting = null;
	return f;
}