/**
 *	device.js for round 3
 */

//Options

var feedbackDelay = 700; //in milliseconds
var traceOn = false;
var smallScrollThumb = true;


var scrollheight = 38;
var viewportlines = 3;
var items, i;


//Sugar

function objectify(id) {
    if (typeof id == 'string') {
        id = document.getElementById(id);
    }
    return id;
}

function addClass(target, classStr) {
    target = objectify(target);

    if (!target.className) {
        target.className = classStr;
    }
    else if (!containsClass(target, classStr)){
        target.className = target.className + " " + classStr;
    }
    return target;
}

function removeClass(target, classStr) {
    target = objectify(target);

    if (!!target.className) {
        var re = new RegExp("\\s*\\b" + classStr + "\\b");
        target.className = target.className.replace(re, "");
    }
    return target;
}

function containsClass(target, classStr) {
    target = objectify(target);
    var regex = new RegExp("\\b" + classStr + "\\b");
    return (!!target && !!target.className && target.className.match(regex));
}

function toggleClass(target, classStr) {
    if (containsClass(target, classStr)) {
        removeClass(target, classStr);
    }
    else {
        addClass(target, classStr);
    }
    return target;
}


// Trace

var trace = {
	on : traceOn,
	add : function(func) {
		if (this.on) {
			var traceListObj = objectify("trace");
			var newListItemObj = document.createElement("LI");
			var funcStr = func.toString();
			if (funcStr.indexOf("function") === 0) {
				funcStr = funcStr.substring(funcStr.indexOf(" "), funcStr.indexOf("("));
				newListItemObj.setAttribute("class", funcStr);
			}
			var newTextObj = document.createTextNode(funcStr);
			newListItemObj.appendChild(newTextObj);
			traceListObj.appendChild(newListItemObj);
			traceListObj.scrollTop = traceListObj.scrollHeight;
		}
	},
	init : function() {
		var newListObj = document.createElement("UL");
		newListObj.setAttribute("id", "trace");
		document.documentElement.appendChild(newListObj);
	}
};


// Basic behaviors and helpers

function getHiIndex() {
	trace.add(arguments.callee);
	for(var i=0; i<items.length; i++){
		if (containsClass(items[i], "hi")) {
			return i;
		}
	}
	return -1;
}

function scrollUp() {
	trace.add(arguments.callee);
	for(var i=0; i<items.length; i++){
		if (containsClass(items[i], "on")) {
			removeClass(items[i+viewportlines-1], "on");
			addClass(items[i-1], "on");
			break;
		}
	}
}

function highlightUp() {
	trace.add(arguments.callee);
	var hiIndex = getHiIndex();
	removeClass(items[hiIndex], "hi");
	addClass(items[hiIndex-1],"hi");
}

function scrollDown() {
	trace.add(arguments.callee);
	for(var i=0; i<items.length; i++){
		if (containsClass(items[i], "on")) {
			removeClass(items[i], "on");
			addClass(items[i+viewportlines], "on");
			break;
		}
	}
}

function highlightDown() {
	trace.add(arguments.callee);
	var hiIndex = getHiIndex();
	removeClass(items[hiIndex], "hi");
	addClass(items[hiIndex+1],"hi");
}

function updateScroll() {
	trace.add(arguments.callee);
	if (items.length <= viewportlines){
		addClass(objectify("scroll"), "off");
		return;
	}
	var height = (smallScrollThumb) ? scrollheight*(1/items.length) : scrollheight*(viewportlines/items.length);
	objectify("scrollindicator").style.height=height + "px";
	for(var i=0; i<items.length; i++){
		if (containsClass(items[i], "hi")) {
			var position = ((scrollheight-height)/(items.length-2))*i+"px";
			objectify("scrollindicator").style.top=position;
		 	break;
		}
	}
}

function moveToTop() {
	trace.add(arguments.callee);
	if (items.length <= viewportlines) {
		for(var i=0; i<items.length; i++) { //clear elements
			removeClass(items[i], "hi");
		}
		for(var i=0; i<items.length; i++) {
			if (!containsClass(items[i], "info") && !containsClass(items[i], "entervalue") && !containsClass(items[i], "unitofmeasure") && (items[i].id != "endofmenu")) {
				addClass(items[i], "hi");
				break;
			}
		}
		return;
	}
	for(var i=0; i<items.length; i++) { //clear elements
		removeClass(items[i], "on");
		removeClass(items[i], "hi");
	}
	for(var i=0; i<viewportlines; i++) { //turn on the right ones
		addClass(items[i], "on");
	}
	for(var i=0; i<viewportlines; i++) { //turn on the right ones
		if (!containsClass(items[i], "info") && !containsClass(items[i], "entervalue") && !containsClass(items[i], "unitofmeasure") && (items[i].id != "endofmenu")) {
			addClass(items[i], "hi");
			break;
		}
	}
}

function moveToBottom() {
	trace.add(arguments.callee);
	if (items.length <= viewportlines) {
		for(var i=0; i<items.length; i++) { //clear elements
			removeClass(items[i], "hi");
		}
		addClass(items[items.length-1], "hi");
		return;
	}
	for(var i=0; i<items.length; i++) { //clear elements
		removeClass(items[i], "on");
		removeClass(items[i], "hi");
	}
	for(var i=items.length-1; i>=items.length-viewportlines; i--) {
		addClass(items[i], "on");
	}
	for(var i=items.length-1; i>=items.length-viewportlines; i--) {
		if (!containsClass(items[i], "info") && !containsClass(items[i], "entervalue") && !containsClass(items[i], "unitofmeasure") && (items[i].id != "endofmenu")) {
			addClass(items[i], "hi");
			break;
		}
	}
}

function getFeedback(obj) {
	trace.add(arguments.callee);
	return obj.getAttribute('feedback') || false;
}

function showFeedback(feedbackClassStr) {
	trace.add(arguments.callee);

	var deviceObj = objectify('device');
	for (i in deviceObj.childNodes) {
		if (deviceObj.childNodes[i].nodeType == 1) {
			deviceObj.childNodes[i].style.display = "none"; //hide children of "device" DIV
		}
	}

	var newDivObj = document.createElement("DIV");
	newDivObj.setAttribute("class", feedbackClassStr);
	newDivObj.setAttribute("id", "feedback");
	deviceObj.appendChild(newDivObj);
}


// Button actions

function down() {
	trace.add(arguments.callee);
	if (items.length <= viewportlines) { //if a non-scrolling menu
		if (containsClass(items[items.length-1], "hi")) { //if the last item in the menu is highlighted
			moveToTop();
		}
		else {
			highlightDown();
		}
		updateScroll();
	}
	else { //a scrolling menu
		if (containsClass(items[items.length-1], "on")) { //if the last item in the menu is visible
			moveToTop();
			updateScroll();
			return;
		}
		else if (!containsClass(items[0], "hi")) { //if the first item in the entire menu is not highlighted
			scrollDown();
		}
		highlightDown();
		updateScroll();
	}
}

function up() {
	trace.add(arguments.callee);
	var hiIndex = getHiIndex();
	if (items.length <= viewportlines) { //if a non-scrolling menu
		if (containsClass(items[0], "hi") || containsClass(items[hiIndex-1], "info")) { //if the first item in the menu is highlighted OR the item above the highlight is informational
			moveToBottom();
		}
		else if (!containsClass(items[hiIndex-1], "info")) { //the item above the highlight is not informational
			highlightUp();
		}
		updateScroll();
	}
	else { //a scrolling menu
		if (containsClass(items[0], "hi") || containsClass(items[hiIndex-1], "info")) { //if the first item in the menu is highlighted OR the item above the highlight is informational
			moveToBottom();
			updateScroll();
			return;
		}
		else if (!containsClass(items[0], "on")) { //if the first item in the entire menu is not yet visible
			scrollUp();
		}
		if (!containsClass(items[hiIndex-1], "info")) { //the item above the highlight is not informational
			highlightUp();
		}
		updateScroll();
	}
}

function handleButton(anchorObj) {
	trace.add(anchorObj.id);
	anchorObj.blur();

	var hrefStr = anchorObj.getAttribute('href');
	if (hrefStr != "#" && hrefStr !== "" && (hrefStr.indexOf("#") != (hrefStr.length-1))) {
		trace.add("direct");
		var feedback = getFeedback(anchorObj);
		if (feedback) {
			showFeedback(feedback);
			deferNavigation(hrefStr);
			return false;
		}
		return true;
	}
	else {
		trace.add("indirect");
		switch(anchorObj.id) {
			case ("up"):
				up();
				break;
			case ("down"):
				down();
				break;
			case ("esc"): // this may be vestigial
				trace.add("used history.back() on ESC button");
				history.back();
				break;
			case ("act"):
				var hiIndex = getHiIndex();
				var actObj = objectify("act");
				if (hiIndex != -1) {
					var hrefStr = items[hiIndex].getAttribute('href');
					var feedback = getFeedback(anchorObj) || getFeedback(items[hiIndex]);
					if (feedback) {
						showFeedback(feedback);
						deferNavigation(hrefStr);
					}
					else {
						actObj.href = hrefStr;
						return true;
					}
				}
				break;
			default:
				alert("Button not implemented.");
		}
	}
	return false;
}

function deferNavigation(hrefStr) {
	self.setTimeout( function() {
		location.href = hrefStr;
	}, feedbackDelay);
}
		
		
// Init

window.onload = function() {
	if (trace.on) {
		trace.init();
	}
	items = objectify("Menu").getElementsByTagName("LI");
	var buttons = objectify("controls").getElementsByTagName("A");
	for(var i=0; i<buttons.length; i++) {
		buttons[i].onclick = function() {
			return handleButton(this);
		};
	}
	updateScroll();
};

/* Notes
	Reserved words: http://www.irt.org/script/1076.htm
	TODO:
		Thorough test
		Optimize/streamline/modularize
		Clean up trace logging
*/