/**
 *    Copyright (c) 2009-2010, As Is Software, dba Media Lab Inc.
 *    http://www.medialab.com
 */

/*global $ml, $, Tween, fc_tb_init */

/*
 * 	Notes:
 * 	1. Nice HTML thumbsheet here: http://plt-scheme.org/screenshots/
 */

var com;
if(!com) { com = {}; } else if(typeof(com) != "object") { throw new Error("can't initialize...com is not an object."); }
if(!com.medialab) { com.medialab = {}; } else if(typeof(com.medialab) != "object") { throw new Error("can't initialize...com.medialab is not an object."); }
if(!com.medialab.sg) { com.medialab.sg = {}; }
if (!com.medialab.sg.gallery1) { com.medialab.sg.gallery1 = {};}


com.medialab.sg.gallery1.scrollPanel =
function (thumbSheetXMLIn, modeIn, docentIn) { 
	var debug = false;
	var sgalert = function(msg) { if (debug) {
		alert(msg);
	} };
	var docent= docentIn;

    docent.sgconsole("panel docent: " + docentIn);
	var xml = thumbSheetXMLIn;
    var cssInitialized=false;
	var that=this;
	var thumbWidth = 0;
	var thumbHeight = 0;
	var sheetWidth = 0;
	var sheetHeight = 0;
	var sheetMode = modeIn;
	if(typeof(sheetMode)=='undefined') { sheetMode = 'exhibit'; }
	var panelPadding = 0;
	var panelBorderWidth = 0;
	var loopBack = true;
	var curPos = 0;
	var currentPanel=0;
	var tweenTime=1;
	var panelsContainer = "not set yet";
	var tweenFunc = Tween.regularEaseInOut;
	var tween = "not set yet";  // will hold the actual tween object
	var numAtOnce = "not set yet";  // how many panels are visible at a time
	var numPanels = "not set yet";
	var sheetDivID = "not set yet";
	var panelClassName = "not set yet";
	var thumbDivID = "not set yet";
	var linkClass = "not set yet";
	var changeimageonhover = "false";
	var clickAction = "not set yet";	
	var sheetOrientation = "horizontal";
	var backgroundHoverChange = "not set yet";	
	var backgroundClickable = "not set yet";	
	var backgroundHoverColor = "not set yet";
	var dataUrl = '';
	var dataType ='gallery';
	var useHtmlMetadata = false;
	var panelSetupComplete = false;
	var thumbClassName = 'not set yet';
	var panelHeight = 'not set yet';
	var panelWidth = 'not set yet';
	var playDelay = 3000;
	var autoPlay = true;
	var feedItems = null;
	var player = null;
	
// BEGIN FUNCTIONS IDENTICAL IN ALL PANELSHEETS

// finds delimited metadata keys in a str and replaces them with the actual metadata for that exhibit number  
// shopuld go in docent?
	function replaceMetaData(str, exNum) {
	    if(typeof str != 'string') {return;}
	    var mdStartDelim = "[[";
	    var mdEndDelim = "]]";
	    var mdataStart = str.indexOf(mdStartDelim);
	    var mdataEnd = str.indexOf(mdEndDelim);
	    while (mdataStart > -1 && mdataEnd > mdataStart) {
	    	var mdReplace = str.substring(mdataStart,mdataEnd+2);
	    	var mdKeyword = str.substring(mdataStart+2,mdataEnd);
	    	var mdata = docent.getMetadata(mdKeyword, exNum);
	    	str = str.replace(mdReplace,mdata);
	  		mdataStart = str.indexOf(mdStartDelim);
	    	mdataEnd = str.indexOf(mdEndDelim);
	    }  
	    return str;
	}

// Finds all <a> elements in the panelsheet and translates them from SG's link table and replaces metadata
	function convertHrefs() {
		var curEntry = -1;
		var panelsElement = $ml('#' + sheetDivID + ' a');
		var numEntriesPerPanel = panelsElement.length/numPanels;
		panelsElement.each(function(n) {
			if(n % numEntriesPerPanel === 0) { curEntry++; }
	        var initHref = $ml(this).attr('href');
			var intermediateHref = docent.translate_link(initHref);
	        var finalHref = replaceMetaData(intermediateHref,curEntry);
	        finalHref = encodeURI(finalHref);
	        $ml(this).attr('href',finalHref);
		});
	}
	
	function setGalleryMetaData(element, curEntry, metaDataName){
		var metaContents = $ml.trim($ml('exhibits exhibit:eq('+curEntry+') views view:eq(0) metadata[name='+metaDataName+']', xml).text());
		$ml(element).html(metaContents);
	}
	
	function getPropIgnoreCase(propToFindMixedCase, objectToLookIn) {
		if(typeof propToFindMixedCase != 'string' || typeof objectToLookIn!='object') { return ""; }
		var propToFind = propToFindMixedCase.toLowerCase();
		for (var tryProp in objectToLookIn) {
			var lowProp = tryProp.toLowerCase();
			if(lowProp == propToFind) { return objectToLookIn[tryProp]; }
		}
	}
	
	function excavateObject(ob,propArr) {
		if(typeof(ob) == 'undefined' || ob===null) { return ""; }
		if (propArr.length == 1) {
			return getPropIgnoreCase(propArr[0], ob);  //ob[propArr[0]]; }  changed this to fix mixed case problem
		}
		var curProp = propArr[0];
		propArr.splice(0,1);
		return excavateObject(ob[curProp],propArr);
	}	
		
	function setFeedMetaData(element, itemNum, metaDataName) {
		docent.sgconsole('setFeedMetaData item ' + itemNum + ' feedItems ' + feedItems[itemNum]);
		var mdItem = feedItems[itemNum];
		var mdContent = "";
		// Check a deeper query.  Use metaDataName = "author.name"; for debugging
		if (metaDataName.indexOf('.') > -1) {
			mdContent=excavateObject(mdItem, metaDataName.split('.'));
		}
		else {
			if (metaDataName == 'link') {
				mdContent = getLinkUrlFromJson(feedItems, itemNum);
			}
			else {
				//mdContent = mdItem[metaDataName];  // replaced this with below to fix metadata label capitalization problem
				mdContent = getPropIgnoreCase(metaDataName, mdItem);
				// handle funky entries that embed text in subobjects with identifiers, like blogspot's ATOM feed
				if(typeof mdContent == 'object' && typeof mdContent != 'string') {
					if(typeof mdContent.content == 'string') {
						mdContent = mdContent.content;
					} else {
						mdContent = "";
					}
				}
			}
		}
		if (typeof(mdContent) != 'undefined' && mdContent !== null) {
			var feedText = null;
			// The data is a link
			if (mdContent.indexOf('http://') === 0) {
				//function isURL(s) { var regexp = /http:\/\/[A-Za....-]{3,}\.[A-Za-z]{3}/; return regexp.test(s); } 
				//$ml(element).html('<a href="' + mdContent + '">' + mdContent + '</a>');
				$ml(element).html('<a href="' + mdContent + '">' + 'link' + '</a>');
			}
			// The data is a html (starts with a < )
			else if (mdContent.indexOf('<')===0) {
				if(useHtmlMetadata){
					$ml(element).html(mdContent);
				} else {
					////var fixedContent = mdContent.replace(/&(lt|gt);/g, function (strMatch, p1){ return (p1 == "lt")? "<" : ">"; });
					//$ml(element).text( $ml(mdContent).text() );
					
					// Clean HTML tags out of text
					feedText = mdContent.replace(/<\/?[^>]+(>|$)/g, "");
					// convert html entities (like &quot;)
					$ml(element).text( cleanHtmlEntities(feedText) );
				} 
			}
			// The data is something else
			else {
				//$ml(element).text( $ml(mdContent).text() );
				
				// Clean HTML tags out of text
				feedText = mdContent.replace(/<\/?[^>]+(>|$)/g, "");
				// convert html entities (like &quot;)
				$ml(element).text( cleanHtmlEntities(feedText) );
			}
		}
	}
	
	function cleanHtmlEntities(dirtyString) {
	  var ta=document.createElement("textarea");
	  ta.innerHTML=dirtyString.replace(/</g,"&lt;").replace(/>/g,"&gt;");
	  return ta.value;
	}
	
	
	function setMetaData(element,num,name) {
		if(dataType!='feed') { setGalleryMetaData(element,num,name); }
		else { setFeedMetaData(element,num,name);}
	}
	
	function getThumbPath(thumbNum){
		if(dataType=='feed') { return getImageUrlFromJson(feedItems, thumbNum); }
		else {
			if(sheetMode == 'exhibit') {
				return $ml.trim($ml('exhibits exhibit:eq('+ thumbNum +') view:eq(0) thumbnail url',xml).text());
			} 
			else {
				return $ml.trim($ml('exhibits exhibit:eq('+ docent.getCurrentExhibit() +') view:eq('+ thumbNum +') thumbnail url',xml).text());
			}
		}
	
	}

	function setUpPanelsData() {		
		// hrefs
		convertHrefs();
		if (typeof fc_tb_init == 'function') {  // pre version .7 of foxycart needs this for dynamically added elements
			fc_tb_init('a.foxycart');
		} 

		// content metadata			
		var searchString = 'div[class="' + panelClassName + '"]:eq(0) span[class*='+ docent.getName() +']';
		var numEntriesPerPanel = $ml(searchString).length;
		var curEntry = -1;
		//$ml('div[class="'+ panelClassName + '"] span[class*="'+ docent.getName() +'"]').each(function (n) {	// same as below?
		$ml('#' + sheetDivID +  ' span[class*="'+ docent.getName() +'"]').each(function (n) {	
			if(n % numEntriesPerPanel === 0) { curEntry++; }
			var fullClassName = $ml(this).attr('class');
			var metaDataName = fullClassName.split(' ')[1];
			setMetaData(this, curEntry, metaDataName);
		});	
		
			
		// thumb images & links
		if(typeof thumbClassName =='string' && thumbClassName !== '' && thumbWidth>0 && thumbHeight>0) {
			searchString = 'div[class="'+ panelClassName + '"] div[class*="'+ thumbClassName +'"]';
			docent.sgconsole(searchString);
			$ml(searchString).each(function(n) {
				var link = null;
				var tHtml = "";
				var thumbPath = '#';
				var tPath = getThumbPath(n);
				var styleString = 'position:inherit; width:'+ thumbWidth +'px; height:'+ thumbHeight +'px; background-image:url('+ docent.url2CssUrl(tPath) + '); background-position: 50% 50%; background-repeat: no-repeat;';
				switch (clickAction) {
					case 'picturebox':
					case 'bigbox':
					case 'picturebox':
						tHtml += '<a href="#"';
						break;
					case 'url':
						link = $ml.trim($ml('exhibits exhibit:eq('+ n +') view:eq(0) link',xml).text());
						tHtml += '<a href="' + link + '" ';
						break;
					case 'feedlink':
						link = "#"; 
						if (dataType == 'feed') {
							link = getLinkUrlFromJson(feedItems, n);
						}
						tHtml += '<a href="' + link + '" ';					
						break;
					default:
						$ml(this).attr('style',styleString);
						break;
				}
				if(tHtml!== '') { 
					tHtml += '><div style="'+styleString+'"></div></a>';
	
					$ml(this).append(tHtml);
				}		
			});
		}
	}
        
	function initPanelSheet() {
		// generate generic HTML for all panel sheets
		var containerText = getPanelSheetContainerStartHTML();
		containerText += getEmptyPanelsHTML();
		containerText += getPanelSheetContainerEndHTML();
		containerText += '<div style="clear:left"></div>';

		// add generic HTML to page html
		$ml("#"+sheetDivID).html(containerText);
		
		setUpPanelsData();
		setUpPanelsEvents();
				
		// now finish
		initCustomPanelSheetStuff();
		that.panelSetupComplete();		
	}
	
	
	function getEmptyPanelsHTML() { 
		var panelsHTML = "";
		//var onePanelHTML = $ml('panels > panel > div', xml).toXML();  // pre kludge
		var onePanelHTML = $ml('panels > panel > div:eq(0)', xml).toXML();  // kludge to avoid <divider> that shouldn't be there
		for(var curPanelCounter = 0; curPanelCounter < numPanels; curPanelCounter++) {
			panelsHTML += onePanelHTML;
		}
		return panelsHTML;
	}
	
	function getOption(opt) {
		var w = docent.getPanelOption(sheetMode,opt);
		//var w = $ml('option[varname='+opt+']', options).attr("value");
		return w;
	}
	
	function getFirstPropertyFromObject(ob) {
		for(var i in ob) { 
			return ob[i]; }
	}
	

	
	function getImageUrlFromJson(dataArr,itemNum) {
		var img="";
		if(dataArr.length > itemNum) {
			var item = dataArr[itemNum];
			if (typeof(item.content) != 'undefined') {
				if(typeof item.thumbnail == 'object' && typeof item.thumbnail.url == "string") {  // check for an existing thumbnail entry as in blogspot ATOM
					return item.thumbnail.url;
				}
				else if (typeof item.content.url != "undefined") { // assume image in content poperty 1st as in http://rss.news.yahoo.com/rss/topstories
					return item.content.url;
				} else if(typeof item.content.content != 'undefined') {
					img=getImageFromContent(item.content);  // try finding it in description HTML
					if(img!=="") { return img; }
				}
			}
			img=getImageFromDescription(item);  // try finding it in description HTML
			if(img!=="") { return img; }
			img = getImageFromLink(item);  // Flickr-style, as in http://api.flickr.com/services/feeds/photoset.gne?set=72157623884410853&nsid=25976997@N03&lang=en-us
			if(img!=="") { return img; }
		}
		return img;
	}
	
	function getImageFromLink(item) {
		var img = "";
		if(typeof (item.link) != "undefined") {
			var linkObj = findObjectInArrayWith('type','image/jpeg',item.link);
			if(typeof linkObj == 'object' && linkObj!==null) {
				if(typeof linkObj.href == "string") {
					return linkObj.href;
				}
			}		
		}
		return "";
	}
	
	function findObjectInArrayWith(propName,propVal,objArr) {
		if(typeof objArr == 'object' && objArr!==null) {
			for(var i=0; i < objArr.length; i++) {
				var testObj = objArr[i];
				if (typeof testObj == 'object' && testObj!==null) {
					if(typeof testObj[propName] != 'undefined') {
						if (testObj[propName] == propVal) {
							return testObj;
						}
					}
				}
			}
		}
		return null;
	}
	
	function getImageFromContent(item) {
		var img = "";
		if(typeof (item.content) != "undefined") {
			var h = "<div>" + item.content + "</div>";
			var imgArr = $ml('img',h);
			if (typeof imgArr != "undefined" && typeof imgArr[0] != "undefined" && typeof imgArr[0].src != "undefined"){
				img = imgArr[0].src;
			}
		}
		return img;
	}
	
	function getImageFromDescription(item) {
		var img = "";
		if(typeof (item.description) != "undefined") {
			var h = "<div>" + item.description + "</div>";
			var imgArr = $ml('img',h);
			if (typeof imgArr != "undefined" && typeof imgArr[0] != "undefined" && typeof imgArr[0].src != "undefined"){
				img = imgArr[0].src;
			}
		}
		return img;
	}
	
	function getLinkUrlFromJson(dataArr, itemNum){
		if(dataArr.length > itemNum) {
			var item = dataArr[itemNum];
			var vType = typeof(item.link);
			var strLink = item.link
			switch(vType) {
				case 'string':
					return strLink;
				case 'object':
					var it = item.link;
					if(typeof it=='object' && typeof it.href == 'string') { return it.href; }
					else{
						if (typeof it == 'object') {
							var linkObj = findObjectInArrayWith('type','text/html',it);
							if(typeof linkObj.href == 'string' && linkObj.href.substring(0,4) == 'http') {
								return linkObj.href;
							}
						}
					}
					return it.href;
				//case 'undefined':
				default:
					return "";
				//return item.content.url;
			}
		}
	}
	
	this.select = function (thumbnum) {
		// called whenever a new image is selected to sync
		// could be called becuase a thumb (including this one) is clicked
		// or for any other reason the docent wants, like next/prev buttons.
		
		// don't do anything if already synced 
		
		// If not synced then hilite apropriate thumb if necessary and dehilite others if necessary
		docent.sgconsole("thubsheet select called");
		initSheet();
	};

	function jqClick(e) {
		var thumbNum = e.data.thumbNum;
		//alert('thumb ' + thumbNum);
		docent.sgconsole('css '+ sheetMode +' thumb '+ thumbNum +' clicked');
		switch (clickAction) {
			case 'picturebox':
				docent.selectThumb(thumbNum,sheetMode,true);
				break;
			case 'bigbox':
				docent.selectThumb(thumbNum,sheetMode,true);
				docent.openBigbox(sheetMode);
				break;
			case 'url' :
				docent.gotoCustomUrl(thumbNum);
				break;
			case 'feedlink' :
				//
				// added exteranl link confirmation by Digital Housing & Administration, LLC - kjt - 2011-04-01
				//
				if(confirm('You are about to be linked to a website that is not controlled or administered by Pacific Valley Bank, Pacific Valley Bank does not make any warranty or assume legal liability or any other responsibility for the content, accuracy, or opinions expressed in websites controlled by other entities.\n Click \"OK\" to continue or \"Cancel\" to go back. Continue?')){
					docent.gotoUrl(e.data.feedLink);
				}
				//
				// original code - kjt - 2011-04-01
				//
				//docent.gotoUrl(e.data.feedLink);
				break;
			default:
				docent.sgconsole('css thumbs passed unknwn click action '+ clickAction);
				break;
		}
		return false;
	}

	function setUpPanelsEvents() {
		var numPanelsAdded = $ml('#'+sheetDivID + ' [class="' + panelClassName + '"]').length;
		// 	Set up click events
		
		for (var curPanel = 0; curPanel < numPanelsAdded; curPanel++) {
			var eventInfo = {};
			eventInfo.thumbNum=curPanel;
			if (dataType =='feed') {
				eventInfo.feedLink = getLinkUrlFromJson(feedItems, curPanel);
			}
			if (clickAction && clickAction != 'none') {
				if (backgroundClickable) {
					$ml('div[class*="' + panelClassName + '"]:eq('+ curPanel +')').bind('click', eventInfo, jqClick);
				}
				else { // only the thumb is clickable
					$ml('div[class*="' + thumbClassName + '"] a:eq('+ curPanel + ')').bind('click', eventInfo, jqClick);
				}
			}
		}
		
		// 	Set up style events
		
		if (clickAction && clickAction != 'none') {
			if (backgroundClickable) {
				$ml('div[class="' + panelClassName + '"]').css('cursor', 'pointer');
				if(backgroundHoverChange) {
				$ml('div[class="' + panelClassName + '"]').hover(
					function(e) { $ml(this).css('background-color',backgroundHoverColor);}, 
					function(e) { $ml(this).css('background-color','transparent'); }); // or do we need to capture initial color?
				}
			}
			else { // only the thumb is clickable
				$ml('div[class="' + thumbClassName + '"] a').css('cursor', 'pointer');
			}
		}
	}	

// END FUNCTIONS IDENTICAL IN ALL PANELSHEETS
// ********************************************
// BEGIN FUNCTIONS IMPLEMENTED IN ALL PANELSHEETS BUT THAT ARE NOT THE SAME

	// a good test url for json is http://rss.news.yahoo.com/rss/topstories
	this.gotJSON = function(jsonData) {
		if (typeof jsonData == 'object' && typeof jsonData.query == 'object' && typeof jsonData.query.results == 'object') {
			feedItems = getFirstPropertyFromObject(jsonData.query.results);
			if (typeof(feedItems) == 'undefined' || feedItems === null) {
				$ml("#" + sheetDivID).html('<p>No data found at feed:</p><p>' + dataUrl + '</p>');
				return;
			}
			numPanels = feedItems.length;
			docent.sgconsole('numPanels from feed: ' + numPanels);
			initPanelSheet();
		}
		else {
			$ml("#" + sheetDivID).html('<p>Problem with feed data:</p><p>' + dataUrl + '</p>');
		}
	};
	
	function getPanelSheetContainerEndHTML() {
		return '</div></div>';
	}

	function initCustomPanelSheetStuff() {  // will be custom depending on panel type
		$ml('div[class="' + panelClassName + '"]').css('overflow','hidden');  // necessary?
		  // set up tween
		var axis = sheetOrientation=='horizontal' ? 'left' : 'top';
		panelsContainer = $ml("#"+sheetDivID + " > div > div")[0];
		tween = new Tween(panelsContainer.style,axis,tweenFunc,0,0,1,'px');
		  // set up margins
		var marg = sheetOrientation == 'horizontal' ? 'margin-left' : 'margin-top';
		panelPadding = parseInt($ml('div[class="' + panelClassName + '"]').css(marg),10);
		if (isNaN(panelPadding)) { panelPadding = 0; }
	}
	
	function getPanelSheetContainerStartHTML() { // will be custom depending on panel type
		// Basic scroll panel
		var containerText = '<div style="width:' + sheetWidth + 'px;height:' + sheetHeight + 'px;overflow:hidden;position:relative;">'; // position relative fixes IE bug with overlfow hidden
		var extent = that.getPanelsExtent();  // axis size based on h/v orientation of sheet
		if(sheetOrientation=='horizontal') {
			containerText += '<div style="height:'+panelHeight+'px; width:'+extent+'px; left:0; top:0;position:relative;">';
		} else {
			containerText += '<div style="height:'+extent+'px; width:'+panelWidth+'px; left:0; top:0;position:relative;">';
		}
		return containerText;
	}

	 function processXML () {
		sgalert("SG Standard Thumbsheet: processXML", this);

		dataUrl = getOption('dataurl');
		dataType = getOption('datatype');
		//panelBorderWidth = getOption('panelborderwidth');
		clickAction = getOption('clickaction');
		//panelPadding = getOption("spacing");
		//if(typeof(panelPadding)!='number') { panelPadding = getOption("hspacing"); }
		sheetWidth = getOption("sheetwidth");
		sheetHeight = getOption("sheetheight");
		panelWidth = getOption("panelwidth");
		panelHeight = getOption("panelheight");
		thumbWidth = getOption("thumbwidth");
		thumbHeight = getOption("thumbheight");
		thumbClassName = getOption("panelthumbclass");
		sheetDivID = getOption("sheetdivname");
		thumbDivID = getOption("thumbdivname");
		useHtmlMetadata = getOption('usehtmlmetadata');
		changeimageonhover = getOption("changeimageonhover");
		loopBack =  getOption("loopback");
		backgroundHoverChange = getOption("backgroundohoverchange");
		backgroundClickable = getOption("backgroundclickable");
		backgroundHoverColor = docent.toCSSColor(getOption("backgroundhovercolor"));
		tweenTime = getOption('tweenduration');
		playDelay = getOption('playdelay') * 1000 + tweenTime*1000;
		autoPlay = getOption('autoplay');

		var tweenFuncName = getOption("tweenfunction");
		if(typeof(Tween[tweenFuncName]) == 'function') { tweenFunc = Tween[tweenFuncName]; }

		sheetOrientation = getOption('sheetorientation');
		if(sheetOrientation=='auto' || sheetOrientation === '') { 
			sheetOrientation = (sheetWidth-panelWidth >= sheetHeight-panelHeight) ? 'horizontal' : 'vertical';
		}
		
		if(sheetMode=='exhibit') { numPanels = docent.getExhibitCount(); }
		else { numPanels = docent.getNumViews();}
		docent.sgconsole('numpanels: ' + numPanels);
		panelClassName = $ml.trim($ml('panels > panel > div',xml).attr('class'));
		panelClassName = panelClassName.replace('  ',' ');

		var size = sheetOrientation == 'horizontal' ? sheetWidth : sheetHeight;
		numAtOnce = Math.floor(size/that.getPanelExtent());
		docent.sgconsole('panel showing ' + numAtOnce + ' at once out of ' + numPanels + ' total');
		if (numAtOnce === 0) {
			numAtOnce = 1;
		}
		return;
	}
	
	this.panelSetupComplete = function() {
		if(autoPlay) { startPlay(); }
	};

	function init() {
		docent.sgconsole("SG Basic Scroll Panelsheet: Init", this);
		if(getOption("type")!="scrollPanel") { docent.sgconsole("Type mismatch between thumbsheet javascript(scrollPanel) and data ("+getOption("type")+")"); return;}
		if(getOption("version") > 1.0) { docent.sgconsole("Panel javascript version older than data version!"); return;}
		processXML();
		if(dataType=='feed') {
			docent.getJSON(dataUrl, that.gotJSON);
		} else {
			initPanelSheet();
		}
	}


		
	this.updateSheet = function() {
		initSheet();
	};
	
// END FUNCTIONS IMPLEMENTED IN ALL PANELSHEETS BUT THAT ARE NOT THE SAME
// ********************************************
// BEGIN FUNCTIONS TOTALLY UNIQUE TO THIS PANELSHEET
	this.getPanelsExtent = function() {  // get the total width/height of all panels with borders and spacing
		var extent = 0;
		extent += panelPadding * 2 * (numPanels-1);
		extent += panelBorderWidth * 2 * (numPanels-1);
		var size = sheetOrientation=="horizontal" ? panelWidth : panelHeight;
		extent += size * numPanels;
		return extent;
	};
	
	this.getPanelExtent = function() { // get the total width/height of a single panel with borders and spacing
		var extent = 0;
		extent += panelPadding;
		extent += panelBorderWidth * 2;
		var size = sheetOrientation=="horizontal" ? panelWidth : panelHeight;
		docent.sgconsole(panelPadding + " - " + panelBorderWidth + " - " + size);
		extent += size;
		docent.sgconsole('panelsheet getPanelExtent returning ' + extent);
		return extent;
	};
	
	function startPlay() {
		player = setInterval(playNext,playDelay);
	}
	
	function stopPlay() {
		if (player) {
			player.stop();
		}
	}
	
	function playNext() {
		that.nextPanel();
	}
	
	function resetTweenTime() {
		if(player) { 
			clearInterval(player);
			startPlay();
		}
	}
	
	this.goToPanel = function (destPanel) {
		var targetLoc = -destPanel * this.getPanelExtent();
		currentPanel = destPanel;
		if(window.Tween) {
			if(autoPlay) { resetTweenTime(); }
			tween.continueTo(targetLoc, tweenTime);
		}
		else {
			docent.sgconsole("JSTween not found!");
		}
	};
	
	this.nextPanel = function() {
		var nextPanel = currentPanel;
		if (currentPanel >= numPanels - numAtOnce) {
			if (loopBack) {
				nextPanel = 0;
			}
		}
		else {
			nextPanel = currentPanel + 1;
		}
		if(nextPanel != currentPanel) { this.goToPanel(nextPanel); }
		return;
	};
	
	this.previousPanel = this.prevPanel = function() {
		var saveNum = numAtOnce;
		if(currentPanel!==0) { numAtOnce = 1; }  // if at beginning and looping we need to preserve numAtOnce so the loop works
		this.previousPanelSet();
		numAtOnce=saveNum;
	};
	
	this.nextPanelSet = function() {
		var nextPanel = currentPanel;
		var numToSlide = numAtOnce;
		docent.sgconsole('nextPanelSet currentPanel >= numPanels - numAtOnce ' + numPanels + ' ' + numAtOnce + ' ' + currentPanel);
		if(currentPanel >= numPanels - numAtOnce) {			
			if (loopBack) {
				nextPanel = 0;
			}
		}
		else {
			var numLeft = numPanels-(currentPanel + (numAtOnce));
			if (numLeft < numAtOnce) { numToSlide = numLeft; }
			nextPanel = currentPanel + numToSlide;
		}
		
		if(nextPanel != currentPanel) { this.goToPanel(nextPanel); }
		return;
	};
	
	
	this.previousPanelSet = this.prevPanelSet = function() {
		var nextPanel = currentPanel;
		var numToSlide = numAtOnce;
		if(currentPanel === 0) {
			if (loopBack) {
				nextPanel = numPanels - numAtOnce;
			}
		}
		else {
			var numLeft = numPanels-(currentPanel + (numAtOnce));
			if(currentPanel < numAtOnce) { numToSlide = currentPanel; }
			nextPanel = currentPanel - numToSlide;
		}
		if(nextPanel != currentPanel) { this.goToPanel(nextPanel); }
	};	
	


// END FUNCTIONS TOTALLY UNIQUE TO THIS PANELSHEET

	init();
};