var conf = {
	scroll_speed: 0.4,
	scroll_speed_fast: 1.1,
	scroll_friction: 0.8,
	chars: "SANOTEHUCP",
	input_whitelist: ["checkbox", "radio", "hidden", "submit", "reset", "button", "file", "image"],
	location_change_check_timeout: 2000
}

var keys = {
	scroll_up: {code: 84},
	scroll_down: {code: 78},
	scroll_up_fast: {code: 219, shiftKey: true},
	scroll_down_fast: {code: 221, shiftKey: true},
	blobs_show: {code: 68},
	blobs_show_reload: {code: 68, ctrlKey: true},
	blobs_hide: {code: 27},
	blobs_click: {code: 13},
	blobs_click_new_tab: {code: 13, shiftKey: true},
	elem_deselect: {code: 27},
	change_tab_left: {code: 72},
	change_tab_right: {code: 83},
	move_tab_left: {code: 72, shiftKey: true},
	move_tab_right: {code: 83, shiftKey: true},
	history_back: {code: 72, ctrlKey: true},
	history_forward: {code: 83, ctrlKey: true}
}

function isMatch(k, evt) {
	if ((k.code === evt.keyCode)
	&& (!!k.ctrlKey == evt.ctrlKey)
	&& (!!k.shiftKey == evt.shiftKey)
	&& (!!k.altKey == evt.altKey)
	&& (!!k.metaKey == evt.metaKey)) {
		return true;
	}

	return false;
}


//There's a lot we don't want to do if we're not on an actual webpage, but on
//the "speed dial"-ish pages.
var onWebPage = (document.body !== undefined);

function randomChar() {
	var index = Math.floor(Math.random() * conf.chars.length);
	return conf.chars[index];
}

function getElemPos(elem) {
	var curtop = 0;
	var curleft = 0;

	do {
		curtop += elem.offsetTop;
		curleft += elem.offsetLeft;
	} while (elem = elem.offsetParent);

	return {top: curtop, left: curleft};
}

var blobList = {
	blobs: {},
	container: null,

	visible: false,
	needLoadBlobs: true,

	currentKey: "",

	createContainer: function() {
		var container = document.createElement("div");
		container.style =
			"pointer-events: none;"+
			"display: none;"+
			"position: absolute;"+
			"top: 0px;"+
			"left: 0px;"+
			"z-index: 2147483647"; //Max z-index value in most browsers
		document.body.appendChild(container);
		blobList.container = container;
	},

	init: function() {
		if (!onWebPage)
			return;

		blobList.createContainer();

		window.addEventListener("scroll", function() {
			blobList.needLoadBlobs = true;
		});
	},

	currentIndex: 0,
	loadBlobs: function() {
		if (!onWebPage)
			return;

		var linkElems = document.querySelectorAll("a, button, input, textarea");

		//Remove old container contents
		blobList.container.innerHTML = ""

		//Remove old blobs
		blobList.blobs = {};

		var i = 0;
		function addBlob() {
			var linkElem = linkElems[i];
			i += 1;

			if (i > linkElems.length)
				return false;

			if (linkElem === undefined)
				return true;

			//We don't want hidden elements
			if ((linkElem === undefined)
			||  (linkElem.style.display == "none")
			||  (linkElem.style.visibility == "hidden")) {
				return true;
			}

			//Get element's absolute position
			var pos = getElemPos(linkElem);
	
			//Lots of things which don't really exist have an X and Y value of 0
			if (pos.top == 0 && pos.left == 0)
				return true;

			//We don't need to get things far above our current scroll position
			if (pos.top < (window.scrollY - 100))
				return true;

			//We don't need things below our scroll position either
			if (pos.top - 100 > (window.scrollY + window.innerHeight))
				return true;

			var key = randomChar();
			while (blobList.blobs[key])
				key += randomChar();

			var blobElem = document.createElement("div");
			blobElem.innerHTML = key;
			blobElem.style = [
				"position: absolute",
				"background-color: yellow",
				"border: 1px solid black",
				"border-radius: 10px",
				"padding-left: 3px",
				"padding-right: 3px",
				"color: black",
				"top: "+pos.top+"px",
				"left: "+pos.left+"px",
				"line-height: 12px",
				"font-size: 12px"
			].join(" !important;");
			blobList.container.appendChild(blobElem);

			blobList.blobs[key] = {
				blobElem: blobElem,
				linkElem: linkElem
			}
	
			return true;
		}

		while (addBlob()) {};

	},

	showBlobs: function() {
		blobList.visible = true;
		blobList.container.style.display = "block";
	},

	hideBlobs: function() {
		blobList.currentKey = "";
		blobList.visible = false;
		blobList.container.style.display = "none";
	},

	click: function() {
		if (!blobList.visible)
			return;

		var blob = blobList.blobs[blobList.currentKey];
		if (!blob)
			return;

		blob.linkElem.click();
		blob.linkElem.focus();
		blobList.hideBlobs();
	},

	clickNewTab: function() {
		if (!blobList.visible)
			return;

		var blob = blobList.blobs[blobList.currentKey];
		if (!blob)
			return;

		if (blob.linkElem.tagName == "A" && blob.linkElem.href) {
			self.port.emit("tab_open", blob.linkElem.href);
		} else {
			blob.linkElem.click();
			blob.linkElem.focus();
		}

		blobList.hideBlobs();
	},

	appendKey: function(c) {
		blobList.currentKey += c;
	}
}
blobList.init();

//Reload blobs whenever the URL changes
var currentUrl = location.href;
setInterval(function() {
	if (currentUrl !== location.href) {
		blobList.loadBlobs();
	}
	currentUrl = location.href;
}, conf.location_change_check_timeout);

var pressedKeys = [];

function inArray(arr, val) {
	return (arr.indexOf(val) !== -1);
}

function isValidElem(elem) {
	var tag = elem.tagName.toLowerCase();

	if (tag === "textarea")
		return false;

	if (tag === "select")
		return false;

	if (elem.contentEditable.toLowerCase() === "true")
		return false;

	if ((tag === "input")
	&&  (!inArray(conf.input_whitelist, elem.type.toLowerCase()))) {
		return false;
	}

	return true;
}

window.addEventListener("keydown", function(evt) {
	if (/about:.+/.test(location.href))
		return;

	var active = document.activeElement;

	//We don't want to do anything if the user is tpying in an input field,
	//unless the key is to deselect an input field
	if (!isValidElem(active)) {
		if (isMatch(keys.elem_deselect, evt)) {
			active.blur();
		} else {
			return;
		}
	}

	//User is typing a key to a blob
	var c = String.fromCharCode(evt.keyCode);
	if (blobList.visible && conf.chars.indexOf(c) !== -1) {
		blobList.appendKey(c);
		evt.preventDefault();
		evt.stopPropagation();
		return false;
	}

	//Handle other key presses

	//Deselect element
	if (onWebPage && isMatch(keys.elem_deselect, evt)) {
		active.blur();

	//Show/hide/reload blobs
	} else if (onWebPage && !blobList.visible && isMatch(keys.blobs_show, evt)) {
		if (blobList.needLoadBlobs)
			blobList.loadBlobs();
		blobList.needLoadBlobs = false;
		blobList.showBlobs();
	} else if (onWebPage && !blobList.visible && isMatch(keys.blobs_show_reload, evt)) {
		blobList.loadBlobs();
		blobList.needLoadBlobs = false;
		blobList.showBlobs();
	} else if (onWebPage && blobList.visible && isMatch(keys.blobs_hide, evt)) {
		blobList.hideBlobs();

	//Simulate clicks
	} else if (onWebPage && blobList.visible && isMatch(keys.blobs_click, evt)) {
		blobList.click();
	} else if (onWebPage && blobList.visible && isMatch(keys.blobs_click_new_tab, evt)) {
		blobList.clickNewTab();

	//Scrolling
	} else if (onWebPage && isMatch(keys.scroll_up, evt)) {
		scroll.start(-conf.scroll_speed);
	} else if (onWebPage && isMatch(keys.scroll_down, evt)) {
		scroll.start(conf.scroll_speed);
	} else if (onWebPage && isMatch(keys.scroll_up_fast, evt)) {
		scroll.start(-conf.scroll_speed_fast);
	} else if (onWebPage && isMatch(keys.scroll_down_fast, evt)) {
		scroll.start(conf.scroll_speed_fast);

	//Back and forwards
	} else if (isMatch(keys.history_back, evt)) {
		history.back();
	} else if (isMatch(keys.history_forward, evt)) {
		history.forward();

	//Change tab
	} else if (isMatch(keys.change_tab_left, evt)) {
		self.port.emit("change_tab_left");
	} else if (isMatch(keys.change_tab_right, evt)) {
		self.port.emit("change_tab_right");

	//Move tab
	} else if (isMatch(keys.move_tab_left, evt)) {
		self.port.emit("move_tab_left");
	} else if (isMatch(keys.move_tab_right, evt)) {
		self.port.emit("move_tab_right");

	//We don't want to stop the event from propagating
	//if it hasn't matched anything yet
	} else {
		return true;
	}

	evt.preventDefault();
	evt.stopPropagation();
	return false;
}, true);

window.addEventListener("keyup", function(evt) {
	if ((isMatch(keys.scroll_up, evt))
	||  (isMatch(keys.scroll_down, evt))
	||  (isMatch(keys.scroll_up_fast, evt))
	||  (isMatch(keys.scroll_down_fast, evt))) {
		scroll.stop();
	}
}, true);

var scroll = {
	start: function(acceleration) {
		scroll.acceleration = acceleration;

		if (scroll.raf == null)
			scroll.update();
	},

	stop: function() {
		scroll.acceleration = 0;
	},

	update: function() {
		var tdiff = scroll.endTime - scroll.startTime;
		if (tdiff < 100) {
			scroll.velocity += scroll.acceleration;
			window.scrollBy(0, scroll.velocity * tdiff);
			scroll.velocity *= conf.scroll_friction;
		}

		if (tdiff < 10 && scroll.velocity < 0.03 && scroll.velocity > -0.03) {
			scroll.velocity = 0;
			cancelAnimationFrame(scroll.raf);
			scroll.raf = null;
		} else {
			scroll.startTime = scroll.endTime;
			scroll.endTime = new Date().getTime();
			scroll.raf = requestAnimationFrame(scroll.update);
		}
	},

	raf: null,
	acceleration: 0,
	velocity: 0,
	startDate: 0,
	endDate: 0
}