(function() {

	window.apiLogin = apiLogin;
	window.api = api;
	window.elem = elem;
	window.uploadEl = uploadEl;
	window.async = async;
	window.debounce = debounce;
	window.error = error;
	window.$$ = $$;

	function apiLogin(pass, cb) {
		var extraHeads = [ [ "Session-Pass", pass ] ];

		api("login", {}, (err, token) => {
			if (token) {
				document.cookie = "token = " + token;
				cb(true);
			} else {
				cb(false);
			}
		}, extraHeads);
	}

	function argstr(args) {
		return "?" + Object.keys(args).map(function(key) {
			return encodeURIComponent(key)+"="+encodeURIComponent(args[key]);
		}).join("&");
	}

	function api(method, args, cb, extraHeads) {
		var heads = new Headers();
		if (extraHeads)
			extraHeads.forEach(h => heads.append(h[0], h[1]));

		var opts = {
			method: "POST",
			headers: heads,
			credentials: "same-origin"
		};
		fetch("/admin/api/"+method+argstr(args), opts)
			.then(response => response.json())
			.then(res => {
				if (res.err && res.err === "EINVALTOKEN")
					setView("login");
				else
					cb(res.err, res.obj)
			});
	}

	function elem(tag, props, children) {
		var e;
		if (tag instanceof HTMLElement)
			e = tag;
		else
			e = document.createElement(tag);

		if (props) {
			for (var i in props) {
				e[i] = props[i];
			}
		}

		if (children) {
			for (var i in children) {
				e.appendChild(children[i]);
			}
		}

		e.appendTo = function(p) {
			p.appendChild(e);
			return e;
		}

		e.on = function(name, fn) {
			e.addEventListener(name, function(evt) {
				fn(evt, e);
			}, false);
			return e;
		}

		e.addClass = function(name) {
			if (e.className.indexOf(name) !== -1)
				return e;

			e.className += " "+name;
			return e;
		}

		e.removeClass = function(name) {
			e.className = e.className
				.replace(name, "")
				.trim()
				.replace(/ +/, "");
			return e;
		}

		e.clear = function() {
			var fc;
			while (fc = e.firstChild)
				e.removeChild(fc);
			return e;
		}

		return e;
	}

	var uploadElId = 0;
	function uploadEl(args, cb) {
		var id = uploadElId++;
		var frame;
		var form;
		var fileEl;
		return form = elem("form", {
			className: "uploader",
			action: "/admin/api/slide_file_upload"+argstr(args),
			method: "post",
			enctype: "multipart/form-data",
			target: "upload-form-"+id
		}, [
			frame = elem("iframe", {
				style: "display: none",
				name: "upload-form-"+id
			}).on("load", cb),

			fileEl = elem("input", {
				type: "file",
				style: "display: none",
				name: "file"
			}).on("change", () => {
				form.submit();
			}),

			elem("button", {
				innerHTML: "Upload",
				type: "button"
			}).on("click", () => {
				fileEl.click();
			})
		]);
	}

	function async(n, cb) {
		var args = [];
		return function(arg) {
			args.push(arg);

			n -= 1;
			if (n === 0)
				cb(args);
		}
	}

	function debounce(fn, ms) {
		if (ms === undefined)
			ms = 300;

		var timeout;
		return function() {

			if (timeout)
				clearTimeout(timeout);

			timeout = setTimeout(function() {
				fn();
				timeout = null;
			}, ms);
		}
	 }

	function error(msg) {
		alert(msg);
	}

	function $$() {
		return elem(document.querySelector.apply(document, arguments));
	}
})();