var ui = new function() {
	var __top_z_index = 0;
	var __windows = [];
	var __ctl_items = [];

	this.init = function() {
		Array.prototype.forEach.call($$("ctl-item"), function(el_item) {
			el_item.onclick = () => __toggleMenu(el_item);
			__ctl_items.push(el_item);
		});

		Array.prototype.forEach.call($$("window"), function(el_window) {
			var el_grab = el_window.querySelector(".window-header .window-grab");

			__makeWindowMovable(el_grab, el_window);
			__windows.push(el_window);

			var el_button = el_window.querySelector(".window-header .window-button-close");
			if (el_button) {
				el_button.onclick = function() {
					el_window.style.visibility = "hidden";
					__raiseLastWindow();
				};
			}
		});

		var __hidden_attr = null;
		var __visibility_change_attr = null;

		if (typeof document.hidden !== "undefined") {
			__hidden_attr = "hidden";
			__visibility_change_attr = "visibilitychange";
		} else if (typeof document.webkitHidden !== "undefined") {
			__hidden_attr = "webkitHidden";
			__visibility_change_attr = "webkitvisibilitychange";
		} else if (typeof document.mozHidden !== "undefined") {
			__hidden_attr = "mozHidden";
			__visibility_change_attr = "mozvisibilitychange";
		}

		if (__visibility_change_attr) {
			document.addEventListener(
				__visibility_change_attr,
				function() {
					if (document[__hidden_attr]) {
						hid.releaseAll();
					}
				},
				false
			);
		}

		window.onpagehide = hid.releaseAll;
		window.onblur = hid.releaseAll;

		window.onmouseup = __globalMouseButtonHandler;
		// window.oncontextmenu = __globalMouseButtonHandler;

		ui.showWindow("stream-window");
	};

	this.showWindow = function(id) {
		var el_window = $(id);
		if (!__isWindowOnPage(el_window) || el_window.hasAttribute("data-centered")) {
			var view = __getViewGeometry();
			var rect = el_window.getBoundingClientRect();
			el_window.style.top = Math.max($("ctl").clientHeight, Math.round((view.bottom - rect.height) / 2)) + "px";
			el_window.style.left = Math.round((view.right - rect.width) / 2) + "px";
			el_window.setAttribute("data-centered", "");
		}
		el_window.style.visibility = "visible";
		__raiseWindow(el_window);
	};

	var __isWindowOnPage = function(el_window) {
		var view = __getViewGeometry();
		var rect = el_window.getBoundingClientRect();

		return (
			(rect.bottom - el_window.clientHeight / 1.5) <= view.bottom
			&& rect.top >= view.top
			&& (rect.left + el_window.clientWidth / 1.5) >= view.left
			&& (rect.right - el_window.clientWidth / 1.5) <= view.right
		);
	};

	var __getViewGeometry = function() {
		return {
			top: $("ctl").clientHeight,
			bottom: Math.max(document.documentElement.clientHeight, window.innerHeight || 0),
			left: 0,
			right: Math.max(document.documentElement.clientWidth, window.innerWidth || 0),
		};
	};

	var __toggleMenu = function(el_a) {
		var all_hidden = true;

		__ctl_items.forEach(function(el_item) {
			var el_menu = el_item.parentElement.querySelector(".ctl-dropdown-content");
			if (el_item === el_a && window.getComputedStyle(el_menu, null).visibility === "hidden") {
				el_item.classList.add("ctl-item-selected");
				el_menu.style.visibility = "visible";
				all_hidden &= false;
			} else {
				el_item.classList.remove("ctl-item-selected");
				el_menu.style.visibility = "hidden";
			}
		});

		if (all_hidden) {
			document.onkeyup = null;
			__raiseLastWindow();
		} else {
			document.onkeyup = function(event) {
				if (event.code === "Escape") {
					event.preventDefault();
					__closeAllMenues();
					__raiseLastWindow();
				}
			};
		}
	};

	var __closeAllMenues = function() {
		document.onkeyup = null;
		__ctl_items.forEach(function(el_item) {
			var el_menu = el_item.parentElement.querySelector(".ctl-dropdown-content");
			el_item.classList.remove("ctl-item-selected");
			el_menu.style.visibility = "hidden";
		});
	};

	var __globalMouseButtonHandler = function(event) {
		hid.updateLeds();
		if (!event.target.matches(".ctl-item")) {
			for (var el_item = event.target; el_item && el_item !== document; el_item = el_item.parentNode) {
				if (el_item.hasAttribute("data-force-hide-menu")) {
					break;
				}
				else if (el_item.hasAttribute("data-dont-hide-menu")) {
					return;
				}
			}
			__closeAllMenues();
			__raiseLastWindow();
		}
	};

	var __makeWindowMovable = function(el_grab, el_window) {
		var prev_x = 0;
		var prev_y = 0;

		function startMoving(event) {
			__closeAllMenues();
			__raiseWindow(el_window);
			event = (event || window.event);
			event.preventDefault();
			prev_x = event.clientX;
			prev_y = event.clientY;
			document.onmousemove = doMoving;
			document.onmouseup = stopMoving;
		}

		function doMoving(event) {
			el_window.removeAttribute("data-centered");
			event = (event || window.event);
			event.preventDefault();
			var x = prev_x - event.clientX;
			var y = prev_y - event.clientY;
			prev_x = event.clientX;
			prev_y = event.clientY;
			el_window.style.top = (el_window.offsetTop - y) + "px";
			el_window.style.left = (el_window.offsetLeft - x) + "px";
		}

		function stopMoving() {
			document.onmousemove = null;
			document.onmouseup = null;
		}

		el_window.setAttribute("data-centered", "");
		el_grab.onmousedown = startMoving;
		el_window.onclick = () => __raiseWindow(el_window);
	};

	var __raiseLastWindow = function() {
		var last_el_window = null;
		var max_z_index = 0;
		__windows.forEach(function(el_window) {
			var z_index = parseInt(window.getComputedStyle(el_window, null).zIndex);
			if (max_z_index < z_index && window.getComputedStyle(el_window, null).visibility !== "hidden") {
				last_el_window = el_window;
				max_z_index = z_index;
			}
		});
		__raiseWindow(last_el_window);
	};

	var __raiseWindow = function(el_window) {
		el_window.focus();
		hid.updateLeds();
		if (parseInt(el_window.style.zIndex) !== __top_z_index) {
			var z_index = __top_z_index + 1;
			el_window.style.zIndex = z_index;
			__top_z_index = z_index;
			tools.debug("Raised window:", el_window);
		}
	};
};