// Thumbnail slider functionality

var thumbsDiv 			= null;
var intervalDistance 	= 5;	// distance of scroll for each timeout interval
var totalDistanceMoved 	= 0;
var currentPosition 	= 0;
var thumbnailCount  	= 0;	// set in init() on page load
var thumbnailWidth		= 66;  // image width plus padding or margins
var containerWidth		= 395; 	// also set in style sheet
var maxDistance			= 0;	// max distance thumbnail set can scroll to the right before stopping, set in init() on page load
var selectedThumbId		= '';
var timeoutId;

function slideForward() {
	if (totalDistanceMoved < maxDistance) {
		$('scroll_forward').removeClassName('scroll_hide');
		thumbsDiv.style.left = parseInt(thumbsDiv.style.left)-intervalDistance+'px';
		totalDistanceMoved += intervalDistance;
		timeoutId = setTimeout(slideForward,10);
	} else {
		$('scroll_forward').addClassName('scroll_hide');
	}
}

function slideBack() {
	if (totalDistanceMoved != 0) {
		$('scroll_back').removeClassName('scroll_hide');
		thumbsDiv.style.left = parseInt(thumbsDiv.style.left)+intervalDistance+'px';
		totalDistanceMoved -= intervalDistance;
		timeoutId = setTimeout(slideBack,5);
	} else {
		$('scroll_back').addClassName('scroll_hide');
	}
}

function go(direction) {
	thumbsDiv = document.getElementById('scroll_thumbs_container');
	thumbsDiv.style.left = -totalDistanceMoved + 'px';
	currentPosition = totalDistanceMoved;
	switch (direction) {
		case 'forward':
			slideForward();
			break;
		case 'back':
			slideBack();
			break;
	}	
	if (totalDistanceMoved != 0) {
		$('scroll_back').removeClassName('scroll_hide');
	} else {
		$('scroll_back').addClassName('scroll_hide');
	}
	if (totalDistanceMoved < maxDistance) {
		$('scroll_forward').removeClassName('scroll_hide');
	} else {
		$('scroll_forward').addClassName('scroll_hide');
	}
}

function init(collections, firstSelection) {
	thumbnailCount = collections;
	maxDistance = (thumbnailWidth * thumbnailCount) - containerWidth;
	selectThumb(firstSelection);
	if (thumbnailCount < 7) {
		$('scroll_forward').addClassName('scroll_hide');
	}
}

function selectThumb(thumbId) {
	
	var filename = thumbId.replace('thumb_','');
	
	if (selectedThumbId != '') {
		$(thumbId).removeClassName('scroll_thumb_highlight');
		$(selectedThumbId).removeClassName('scroll_thumb_selected');
		$('caption_' + selectedThumbId.replace('thumb_', '')).addClassName('scroll_hide');
		// $('featuredCollectionHeader_' + selectedThumbId.replace('thumb_', '')).addClassName('scroll_hide');
		$('photo_' + selectedThumbId.replace('thumb_', '')).addClassName('scroll_hide');
		// $('collectionImage_' + filename).removeClassName('scroll_hide');
	}

	$(thumbId).addClassName('scroll_thumb_selected');
	selectedThumbId = thumbId;

	$('caption_' + filename).removeClassName('scroll_hide');
	$('photo_' + selectedThumbId.replace('thumb_', '')).removeClassName('scroll_hide');
	// $('featuredCollectionHeader_' + filename).removeClassName('scroll_hide');
	
}

function highlightThumb_over(thumbId) {
	if (thumbId != selectedThumbId) {
		$(thumbId).addClassName('scroll_thumb_highlight');
	}
}

function highlightThumb_out(thumbId) {
	if (thumbId != selectedThumbId) {
		$(thumbId).removeClassName('scroll_thumb_highlight');
	}
}

function stopTimer() {
	clearTimeout(timeoutId);
}