// -- script to implement slideshows --
// author: 		Mike Sadka
// created: 		Feb-April 2005
// related files:	ssSetup.js -not required in this instance

/***** INITIALISE *****/

var ssCurrSlideIndex = 0;						// initialise
var ssMaxSlideIndex = -1;						// initialise
var ssSlides = new Array();						// temporary array of slide object references
var ssRestartable = false;						// initialise
if (typeof ssInterval == 'undefined') var ssInterval = 10000;		// set default milliseconds to display each slide if not already set
if (typeof ssTileWidth == 'undefined') var ssTileWidth = 42;		// set default tile width if not already set - prob unnec as CSS should do this
if (typeof ssLoop == 'undefined') var ssLoop = false;			// set default loop status
if (typeof ssRunning == 'undefined') var ssRunning = false;		// set default run status (NO auto-run)
if (typeof ssSelectable == 'undefined') var ssSelectable = true;	// set default creation of tile selector

// print flag - prevents execution of slideshow when being printed via "print this page" jsp app.
var formatForPrint = (document.location.href.indexOf('print-version') != -1);

if ((W3CDOM) && (!formatForPrint)) {
	window.addOnload(ssSetUp);
}


/***** SETUP *****/
function ssSetUp() {
	if (!W3CDOM) return;						// exit if not dom-compliant browser
	ssSlideshowContainer = document.getElementById('ssSlideshow');	// get entire slideshow div as global object ref
	ssSlideshowContainer.style.visibility = 'hidden';		// hide initially so processing not visible to user
	ssSlides = getElementsByClassName('ssSlide');			// transfer all slide markup to ssSlides array
	ssMaxSlideIndex = ssSlides.length - 1;				// set max slide index value (ie - one less than number of slides)
	for (var i=0;i<ssSlides.length;i++) { 				// for each slide div...
		ssSlides[i].id = 'ssSlide' + i;				// add slide IDs (so can be identified by ssCreateSelector function)
	}
	for (i=0;i<ssSlideshowContainer.childNodes.length;i++) {	// delete all slides (and other text nodes) from slideshow div in HTML source 
		ssSlideshowContainer.removeChild(ssSlideshowContainer.lastChild)
		i--;							// otherwise not all nodes get removed - because the array is being shortened, if i is incremented, nodes get skipped
	}
	ssSlideshowContainer.appendChild(ssCreateControls());		// append control-links div as first child of ssSlideshow
	var ssFirstSlide = ssSlides[ssInitialSlide()];			// re-instate initial (first, unless otherwise specified) slide 
	ssSlideshowContainer.appendChild(ssFirstSlide);
	if (ssSelectable) ssCreateSelector();				// create tile selector - AFTER first slide appended so ssCurrSlideIndex correct
	if (ssSelectable) ssSlideshowContainer.appendChild(ssSelector);	// need to at append selector AFTER slides removed, or it also gets removed
	ssSlideshowContainer.style.visibility = 'visible';		// re-show
	if (ssRunning) ssRun();						// auto-run if ssRunning == true (default is false)
}
function ssCreateControls() {
	ssControllor = document.createElement('DIV');	// create container
	ssControllor.id = 'ssControls';
	ssControllor.className = 'ssMenubar';

	ulTag = document.createElement('UL');		// create menu
	
	liNext = document.createElement('LI');		// create item
	aTag = document.createElement('A');		// create next link
	aTag.id = 'ssNextLink';
	aTag.name = 'nextlink';	
	aTag.href = '#';
	aTag.className = 'pointRight';
	aTag.title = 'Next slide';
	aTag.onclick = ssNext;
	t = document.createTextNode('Next slide');
	aTag.appendChild(t);
	liNext.appendChild(aTag);
	ulTag.appendChild(liNext);

	liRunStop = document.createElement('LI');	// create item
	aTag = document.createElement('A');		// create run/stop link
	aTag.id = 'ssRunStopLink';
	aTag.name = 'runstoplink';	
	aTag.href = '#';
	aTag.className = 'pointRight';
	aTag.title = 'Run slideshow';
	aTag.onclick = ssRun;
	t = document.createTextNode('Run');
	aTag.appendChild(t);
	liRunStop.appendChild(aTag);
	ulTag.appendChild(liRunStop);	

	liPrev = document.createElement('LI');		// create item
	aTag = document.createElement('A');		// create previous link
	aTag.id = 'ssPrevLink';	
	aTag.name = 'prevlink';	
	aTag.href = '#'; 			// not initially...???
	aTag.className = 'pointLeft disabled';
	aTag.title = 'Previous slide';
	aTag.onclick = ssVoid;			// set function as method, so can access index value via this.id
	t = document.createTextNode('Previous slide');
	aTag.appendChild(t);
	liPrev.appendChild(aTag);
	ulTag.appendChild(liPrev);

	ssControllor.appendChild(ulTag);
	return ssControllor;
}
function ssCreateSelector() {
	ssSelector = document.createElement('DIV');	// create tile selector div
	ssSelector.id = 'ssTileSelector';
	for (i=0;i<ssMaxSlideIndex+1;i++) {		// create tiles
		var bool = (i == ssCurrSlideIndex);
		ssSelector.appendChild(ssCreateTile(i, bool));
	}
}
function ssCreateTile(index, status) {
// status: true (current tile) or false (clickable tile)

	slide = ssSlides[index];				// get ref to image of currrent slide
	slideImageObj = slide.getElementsByTagName('IMG');
	slideImageFile = slideImageObj[0].src;

	// AT PRESENT, script assumes thumbnails will be 1 level lower than images in /tns - we will need to change this assumption for Rx-published image files
	lastUnderscorePos = slideImageFile.lastIndexOf('_');	// create thumbnail path and filename
	firstSrcPart = slideImageFile.substring('0',lastUnderscorePos);
	lastSrcPart = slideImageFile.substring(lastUnderscorePos);
	thumbImageFile = firstSrcPart + '_th' + lastSrcPart;

	imageTag = document.createElement('IMG');		// create image tag
	imageTag.src = thumbImageFile;
	imageTag.removeAttribute('width');			// actual width of image gets inserted automatically, so remove it (although would be fine if using correct thumbnail sizes...)
	imageTag.removeAttribute('height');			// actual height of image gets inserted automatically, so remove it
	imageTag.width = ssTileWidth;				// best to set this anyway? - but CSS rule should control tile width
	imageTag.height = ssTileWidth;				// best to set this anyway? - but CSS rule should control tile width
	imageTag.border = '2';					// if don't do this, Opera (and Safari?) has no image borders
	
	aTag = document.createElement('A');			// create A-tag
	if (status) {						// create current tile
		aTag.className = 'ssCurrTileLink';
		aTag.onclick = ssVoid;			// set function as method, so can access index value via this.id
	 	imageTag.className = 'ssCurrTileImage';
	} else {						// create clickable tile
		aTag.className = 'ssTileLink';
		aTag.onclick = ssSelectSlide;			// set function as method, so can access index value via this.id
		//aTag.onmouseover = ssFakeHover_on;
		//aTag.onmouseout = ssFakeHover_off;
		imageTag.className = 'ssTileImage';
	}
	aTag.appendChild(imageTag);
	aTag.id = index;
	aTag.href = '#';

	return aTag;
}
function ssInitialSlide() {
var ssInitialSlideIndex = 0;					// initialise
// NOTE - index starts at 0 but hash uses position, starting at 1
// this doesn't work if already on slideshow page, but works loading from a link
// could use an http param and parse it from the URL if preferable
	if (location.hash.length > 1) { ssInitialSlideIndex = location.hash.substring(1) - 1; }
	ssCurrSlideIndex = ssInitialSlideIndex;	
	return ssInitialSlideIndex;
}
/***** FIX *****/
// this really shouldn't be required, but helps avoid dodgy IE bug (do not have to remove href from link, which causes IE issues)
function ssVoid() {
	this.blur();
	return false;
}
/***** OPERATE *****/
function ssRun() {
	if (ssRestartable) {				// restartable is true only after show has ended without looping, and before any other action has occurred
		ssShowSlide(0);
		setTimeout(ssRun,ssInterval);
		ssRestartable = false;
		ssSetNext(false);
	} else {
		if (!ssRunning) {
			ssNext();
			ssRunning = true;
		}
		ssRunStop(true);
		process = setInterval('ssNext();',ssInterval);
		ssSetNextPrev();
	}
	return false;					// so links not followed
}
function ssStop() {
	ssRunning = false;
	if(typeof process != 'undefined') clearInterval(process);
	ssRunStop(false);
	ssSetNextPrev();
	return false;					// so links not followed
}
function ssRunStop() {
// innerHTML is not a DOM standard, but is useful and very widely supported - miks
	ssRSLink = document.getElementById('ssRunStopLink');
	ssRSLink.innerHTML = (ssRunning? 'Stop' : 'Run');
	ssRSLink.title = (ssRunning? 'Stop slideshow' : 'Run slideshow');
	if (ssRunning) {
		ssRSLink.onclick = ssStop;
	} else {
		ssRSLink.onclick = ssRun;
	}
}
function ssSetNextPrev() {
	if (ssRunning) {
		ssSetNext(false);
		ssSetPrev(false);
	} else {
		if (ssCurrSlideIndex > 0) ssSetPrev(true);
		if (ssCurrSlideIndex == 0) ssSetPrev(false);
		if (ssCurrSlideIndex < ssMaxSlideIndex) ssSetNext(true);
		if (ssCurrSlideIndex == ssMaxSlideIndex) ssSetNext(ssLoop);
	}
}
function ssSetNext(status) {
	ssNLink = document.getElementById('ssNextLink');
	if(status) {
		ssNLink.onclick = ssNext;
		//ssNLink.href = '#';
		ssNLink.className = 'pointRight';
	} else {
		ssNLink.onclick = ssVoid;
		//ssNLink.removeAttribute('onclick');
		//ssNLink.removeAttribute('href');
		ssNLink.className = 'pointRight disabled';
	}
}
function ssSetPrev(status) {
	ssPLink = document.getElementById('ssPrevLink');
	if(status) {
		ssPLink.onclick = ssPrev;
		//ssPLink.href = '#';
		ssPLink.className = 'pointLeft';
	} else {
		ssPLink.onclick = ssVoid;
		//ssPLink.removeAttribute('onclick');
		//ssPLink.removeAttribute('href');
		ssPLink.className = 'pointLeft disabled';
	}
}
function ssPrev() {
	if (ssCurrSlideIndex > 0) {
		var newSlideIndex = ssCurrSlideIndex - 1;
		ssShowSlide(newSlideIndex);
		ssCurrentSlide(newSlideIndex);
	}
	return false;						// so links not followed
}
function ssNext() {
	var newSlideIndex = (ssCurrSlideIndex - 0) + 1;		// -0 forces number datatype, but why this is necessary I have no idea (otherise SOMETIMES gets concatenated rather than summed
	if (newSlideIndex == ssMaxSlideIndex) {			// about to move to last slide
		if (!ssLoop) {
			if (ssRunning) ssRestartable = true;	// end of slideshow - if not looping, run should restart
			ssStop();
		}
	}
	if (newSlideIndex > ssMaxSlideIndex) newSlideIndex = 0;	// loop
	ssShowSlide(newSlideIndex);	
	return false;						// don't follow # href
}
function ssSelectSlide() {
	if(typeof process != 'undefined') ssStop();		// stop slideshow if already running	
	ssShowSlide(this.id);					// only called as method of tiles 
	return false;						// don't follow # href
}
function ssShowSlide(index) {					// replace current slide with new slide
	ssRestartable = (index == ssMaxSlideIndex ? true : false);				// set to true when slideshow ends without looping, but should only be true at that point, so reset if move previous - BUT maybe not needed if ssShowSlide does it...

	if (index != ssCurrSlideIndex) {
		var newSlide = ssSlides[index];
		var oldSlide = document.getElementById('ssSlide' + ssCurrSlideIndex);
		ssSlideshowContainer.replaceChild(newSlide,oldSlide);
		ssCurrTile(index);
		ssCurrentSlide(index);	// do this last, so original index available to ssCurrTile function
	    
	}   
	// if control enablement may have changed, check and set it appropriately
	if ((index == 0) || (index == 1) || (index == ssMaxSlideIndex) || (index == ssMaxSlideIndex - 1)) ssSetNextPrev();
}
function ssCurrentSlide(index) {
	ssCurrSlideIndex = index;
}
function ssCurrTile(index) {
// hover styles do not work in Safari or Opera - could fix this by using js to swap classes rather then relying on hover events... - miks
	if (!ssSelectable) return;					 // exit if no tiles
	var oldTileLink = document.getElementById(ssCurrSlideIndex);
		oldTileLink.onclick = ssSelectSlide;
		oldTileLink.className = 'ssTileLink';
		oldTileLink.firstChild.className = 'ssTileImage';
		//aTag.onmouseover = ssFakeHover_on;
		//aTag.onmouseout = ssFakeHover_off;
	var newTileLink = document.getElementById(index);
		newTileLink.onclick = ssVoid;
		newTileLink.className = 'ssCurrTileLink';
		newTileLink.firstChild.className = 'ssCurrTileImage';
		newTileLink.blur();
		//aTag.onmouseover = ssVoid;
		//aTag.onmouseout = ssVoid;
}
// these functions explicitly change classes to achieve hover without CSS - prob completely unnec as Opera and Safari still don't show it - miks
function ssFakeHover_on() {
	this.className = 'ssTileLink_fakeHover';
}
function ssFakeHover_off() {
	this.className = 'ssTileLink';
}