// convert a single digit (0 - 16) into hex
function enHex(aDigit)
{
    return("0123456789ABCDEF".substring(aDigit, aDigit+1))
}

// convert a hex digit into decimal
function deHex(aDigit)
{
    return("0123456789ABCDEF".indexOf(aDigit))
}

// Convert a 24bit number to hex
function toHex(n)
{
    return (enHex((0xf00000 & n) >> 20) +
            enHex((0x0f0000 & n) >> 16) +
            enHex((0x00f000 & n) >> 12) +
            enHex((0x000f00 & n) >>  8) +
            enHex((0x0000f0 & n) >>  4) +
            enHex((0x00000f & n) >>  0))
}

// Convert a six character hex to decimal
function toDecimal(hexNum)
{
   	var tmp = ""+hexNum.toUpperCase()
	while (tmp.length < 6) tmp = "0"+tmp   
   	return ((deHex(tmp.substring(0,1)) << 20) +
	(deHex(tmp.substring(1,2)) << 16) + 
	(deHex(tmp.substring(2,3)) << 12) +
	(deHex(tmp.substring(3,4)) << 8) +
	(deHex(tmp.substring(4,5)) << 4) +
	(deHex(tmp.substring(5,6))))
}


//global variables
var hoverColour
var numLinks;
var rate;
var numFadeLevels;
var bgR;
var bgG;
var bgB;
var currR;
var currG;
var currB;
var count;
var fadeOut;
var continuous;
var newColour;
var tID;
var redInterval;
var greenInterval;
var blueInterval;

function initLinks(mouseOverColour, numberOfLinks, fadeOutColour)
{
	hoverColour = mouseOverColour;
	numLinks = numberOfLinks;
	rate = 1;
	numFadeLevels = 30;
	
	function initArray(theArray, length, val)
	{
		for(i=0;i<length;i++)
		{
			theArray[i] = val;
		}
	}	

	bgR = '0000' + fadeOutColour.substring(1,3)
	bgG = '0000' + fadeOutColour.substring(3,5)
	bgB = '0000' + fadeOutColour.substring(5,7)
	currR = new Array(numLinks);
	currG = new Array(numLinks);
	currB = new Array(numLinks);
	count = new Array(numLinks);
	fadeOut = new Array(numLinks);
	continuous = new Array(numLinks);
	newColour = new Array(numLinks);
	tID = new Array(numLinks);
	redInterval = toDecimal(bgR) / numFadeLevels;
	greenInterval = toDecimal(bgG) / numFadeLevels;
	blueInterval = toDecimal(bgB) / numFadeLevels;
	initArray(currR,numLinks,0);
	initArray(currG,numLinks,0);
	initArray(currB,numLinks,0);
	initArray(count,numLinks,0);
	initArray(fadeOut,numLinks,true);
	initArray(continuous,numLinks,true);
}	


function startFade(id)
{
	if(fadeOut[id] == true)
	{ /*move colour towards background colour (increment)*/
		currR[id] += redInterval;
		currG[id] += greenInterval;
		currB[id] += blueInterval;
		newColour[id] = '#' + (toHex(currR[id])).substring(4,6) + (toHex(currG[id])).substring(4,6) + (toHex(currB[id])).substring(4,6);
		if(++count[id] == numFadeLevels)
		{
			fadeOut[id] = false;
		}
	}
	else
	{

		currR[id] -= redInterval;
		currG[id] -= greenInterval;
		currB[id] -= blueInterval;
		newColour[id] = '#' + (toHex(currR[id])).substring(4,6) + (toHex(currG[id])).substring(4,6) + (toHex(currB[id])).substring(4,6);
		if(--count[id] == 0)
		{
			fadeOut[id] = true;
		}
	}
	if(continuous[id] == true)
	{
		document.getElementById(id).style.color = newColour[id];		
	}
	else
	{
		document.getElementById(id).style.color = hoverColour;
	}
	clearTimeout(tID[id]);
	tID[id]=setTimeout('startFade(' + id + ')', rate);
}


function continueFade(id)
{
	continuous[id] = true;
}


function stopFade(id)
{
	continuous[id] = false;
}


function StartTimers()
{	//set up an initial set of timers to start the shimmering effect
	for(id=0; id<numLinks; id++)
	{
		t=setTimeout('startFade(' + id + ')', id*100);
	}
}