var currentSection = "sites-pane";
var tabTag = "-tab";
var paneTag = "-pane";


function ScrollSection(link, scrollArea, offset)
{

	if (currentSection == link) {
		return;
	}
	lastSection = currentSection;
	currentSection = link;
	

    sectionTab = currentSection.split("-")[0] + tabTag;
    document.getElementById(sectionTab).className = "active";
    if (lastSection) {
	    lastTab = lastSection.split("-")[0] + tabTag;
	    document.getElementById(lastTab).className = "inactive";
	}
    
	
	theScroll = document.getElementById(scrollArea);
	position = findElementPos(document.getElementById(link));

	
	if (offset != "") {
		offsetPos = findElementPos(document.getElementById(offset));
		position[0] = position[0] - offsetPos[0];
	}

	scrollStart(theScroll, theScroll.scrollLeft, position[0], "horiz");
	// return false;
}


var scrollanim = {time:0, begin:0, change:0.0, duration:0.0, element:null, timer:null};

function scrollStart(elem, start, end, direction)
{
	//console.log("scrollStart from "+start+" to "+end+" in direction "+direction);

	if (scrollanim.timer != null) {
		clearInterval(scrollanim.timer);
		scrollanim.timer = null;
	}
	scrollanim.time = 0;
	scrollanim.begin = start;
	scrollanim.change = end - start;
	scrollanim.duration = 20;
	scrollanim.element = elem;
	
	if (direction == "horiz") {
		scrollanim.timer = setInterval("scrollHorizAnim();", 15);
	}
	else {
		scrollanim.timer = setInterval("scrollVertAnim();", 15);
	}
}

function scrollVertAnim()
{
	if (scrollanim.time > scrollanim.duration) {
		clearInterval(scrollanim.timer);
		scrollanim.timer = null;
	}
	else {
		move = sineInOut(scrollanim.time, scrollanim.begin, scrollanim.change, scrollanim.duration);
		scrollanim.element.scrollTop = move; 
		scrollanim.time++;
	}
}

function scrollHorizAnim()
{
	if (scrollanim.time > scrollanim.duration) {
		clearInterval(scrollanim.timer);
		scrollanim.timer = null;
	}
	else {
		move = sineInOut(scrollanim.time, scrollanim.begin, scrollanim.change, scrollanim.duration);
		scrollanim.element.scrollLeft = move;
		scrollanim.time++;
	}
}

// Utility: Math functions for animation calucations - From http://www.robertpenner.com/easing/
//
// t = time, b = begin, c = change, d = duration
// time = current frame, begin is fixed, change is basically finish - begin, duration is fixed (frames),

function linear(t, b, c, d)
{
	return c*t/d + b;
}

function sineInOut(t, b, c, d)
{
	return -c/2 * (Math.cos(Math.PI*t/d) - 1) + b;
}

function cubicIn(t, b, c, d) {
	return c*(t/=d)*t*t + b;
}

function cubicOut(t, b, c, d) {
	return c*((t=t/d-1)*t*t + 1) + b;
}

function cubicInOut(t, b, c, d)
{
	if ((t/=d/2) < 1) return c/2*t*t*t + b;
	return c/2*((t-=2)*t*t + 2) + b;
}

function bounceOut(t, b, c, d)
{
	if ((t/=d) < (1/2.75)){
		return c*(7.5625*t*t) + b;
	} else if (t < (2/2.75)){
		return c*(7.5625*(t-=(1.5/2.75))*t + .75) + b;
	} else if (t < (2.5/2.75)){
		return c*(7.5625*(t-=(2.25/2.75))*t + .9375) + b;
	} else {
		return c*(7.5625*(t-=(2.625/2.75))*t + .984375) + b;
	}
}


// Utility: Get the size of the window, and set myWidth and myHeight

function getSize() {
	if (document.all) {
		// IE4+ or IE6+ in standards compliant 
		myWidth  = (document.documentElement.clientWidth) ? document.documentElement.clientWidth : document.body.clientWidth;
		myHeight = (document.documentElement.clientHeight) ? document.documentElement.clientHeight : document.body.clientHeight;
		myScroll = (document.documentElement.scrollTop) ? document.documentElement.scrollTop : document.body.scrollTop;
	} else {
		// Non-IE
		myWidth = window.innerWidth;
		myHeight = window.innerHeight;
		myScroll = window.pageYOffset;
	}
	
	// Core code from - quirksmode.org
    if (window.innerHeight && window.scrollMaxY) {	
        myScrollWidth = document.body.scrollWidth;
		myScrollHeight = window.innerHeight + window.scrollMaxY;
	} else if (document.body.scrollHeight > document.body.offsetHeight) { // all but Explorer Mac
		myScrollWidth = document.body.scrollWidth;
		myScrollHeight = document.body.scrollHeight;
	} else { // Explorer Mac...would also work in Explorer 6 Strict, Mozilla and Safari
		myScrollWidth = document.body.offsetWidth;
		myScrollHeight = document.body.offsetHeight;
	}
}

// Utility: Find the Y position of an element on a page. Return Y and X as an array

function findElementPos(elemFind)
{
	var elemX = 0;
	var elemY = 0;
	do {
		elemX += elemFind.offsetLeft;
		elemY += elemFind.offsetTop;
	} while ( elemFind = elemFind.offsetParent )

	//console.log("Found element "+elemFind+" at "+elemY+"/"+elemX);

	return Array(elemX, elemY);
}

function backToTop() {
    var x1 = x2 = x3 = 0;
    var y1 = y2 = y3 = 0;

    if (document.documentElement) {
        x1 = document.documentElement.scrollLeft || 0;
        y1 = document.documentElement.scrollTop || 0;
    }

    if (document.body) {
        x2 = document.body.scrollLeft || 0;
        y2 = document.body.scrollTop || 0;
    }

    x3 = window.scrollX || 0;
    y3 = window.scrollY || 0;

    var x = Math.max(x1, Math.max(x2, x3));
    var y = Math.max(y1, Math.max(y2, y3));

    window.scrollTo(Math.floor(x / 2), Math.floor(y / 2));

    if (x > 0 || y > 0)
        window.setTimeout("backToTop()", 25);
}