/*
 * Original from: http://brainerror.net/scripts/javascript/blendtrans/demo.html
 *
 * Edits by ASC:
 *   - Removed unnecessary OO code that caused MSIE to choke
 *   - Added pause between setting bg image and setting opacity to zero to
 *     prevent MSIE image flash
 *   - Increased opacity check argument to 103 for completely smooth fade
 *
 */

var	savedImage;
var	savedSpeed;
var	savedPause;
var	savedCaption;
var savedOpacity;
var blendTimer;
var pausing = false;
var loaded = false;

//find next image
function nextImage(o) {
    do o = o.nextSibling;
    while(o && o.tagName != 'IMG');
    return o;
}

//find first image inside an element
function firstChildImage(o) {
    
    o = o.firstChild;
        
    while(o && o.tagName != 'IMG') {
        o = o.nextSibling;
    }
    
    return o;
}

//set the opacity of an element to a specified value
function setOpacity(obj, o) {

    obj.style.opacity = (o / 100);
    obj.style.MozOpacity = (o / 100);
    obj.style.KhtmlOpacity = (o / 100);
    obj.style.filter = 'alpha(opacity=' + o + ')';
}

//make image invisible and set next one as current image
function getNextImage(image) {
	
    if (next = nextImage(image)) {
	image.style.display = 'none';
	image.style.zIndex = 0;

	next.style.display = 'block';
	next.style.zIndex = 100;

    } else {
	//if there is not a next image, get the first image again
	next = firstChildImage(image.parentNode);
    }

    return next;
}

//set default values for parameters and starting image
function blendImages(id, speed, pause, caption) {

    if(speed == null) {
        speed = 30;
    }
    
    if(pause == null) {
        pause = 1500;
    }

    var blend = document.getElementById(id);

    var image = firstChildImage(blend);

    startBlending(image, speed, pause, caption);

	loaded = true;
}

//make image a block-element and set the caption
function startBlending(image, speed, pause, caption) {

    image.style.display = 'block';

    //if(caption != null) {
	//document.getElementById(caption).innerHTML = image.alt;
    //}

    continueFadeImage(image, 0, speed, pause, caption);
}

// ASC: copied from http://www.sean.co.uk/a/webdesign/javascriptdelay.shtm
function pausecomp(millis) {
    
	stopTimer( millis )
	
	///var date = new Date();
    ///var curDate = null;

    ///do { curDate = new Date(); }
    ///while(curDate-date < millis);
}

//set an increased opacity and check if the image is done blending
function continueFadeImage(image, opacity, speed, pause, caption)
{
    opacity = opacity + 3;
	
	savedImage = image;
	savedSpeed = speed;
	savedPause = pause;
	savedCaption = caption;
	savedOpacity = opacity;


    if (opacity < 223)
	{

		blendTimer = setTimeout(function() {fadeImage(savedImage, savedOpacity, savedSpeed, savedPause, savedCaption)}, savedSpeed);
    }
	else
	{
	//if the image is done, set it to the background and make it transparent
		image.parentNode.style.backgroundImage = "url("+image.src+")";

		savedPause = pause;

		if( !pausing )
		{
			setOpacity(image,0);
			savedImage = image = getNextImage(image);
			blendTimer = setTimeout(function() {startBlending(savedImage, savedSpeed, savedPause, savedCaption)}, savedPause);
		}
	}
}

//set the opacity to a new value and continue the fading
function fadeImage(image, opacity, speed, pause, caption)
{
    setOpacity(image,opacity);
    continueFadeImage(image, opacity, speed, pause, caption);
}

function pauseOn()
{
	if( !loaded ) return;

	if( blendTimer )
	{
		pausing = true;
		setOpacity(savedImage, 100);
		savedOpacity = 100;
		clearTimeout( blendTimer );
		blendTimer = 0;
	}
}

function pauseOff()
{
	if( !loaded ) return;
	
	pausing = false;
	continueFadeImage(savedImage, savedOpacity, savedSpeed, savedPause, savedCaption );
	//setOpacity(savedImage, 0);
	//savedImage = image = getNextImage(savedImage);
	//blendTimer = setTimeout(function() {startBlending(savedImage, savedSpeed, savedPause, savedCaption)}, savedPause);		
}