/*Sag Content Scroller (Aug 7th, 2010)
* This notice must stay intact for usage 
* Author: Dynamic Drive at http://www.dynamicdrive.com/
* Visit http://www.dynamicdrive.com/ for full source code
*/

//Updated Aug 28th, 10 to v1.3

var sagscroller_constants={
	navpanel: {height:'16px', downarrow:'scroller/down.gif', opacity:0.6, title:'Go to Next Content', background:'black'},
	loadingimg: {src:'ajaxloading.gif', dimensions:[100,15]}
}

function sagscroller(options){

	this.setting={mode:'manual', inittype:'stunted', pause:6000, animatespeed:500, ajaxsource:null, rssdata:null, refreshsecs:0, navpanel:{show:true, cancelauto:false}} //default settings
	jQuery.extend(this.setting, options) //merge default settings with options
	options=null
	this.curmsg=0
	this.addloadingpanel(jQuery, 'preload')
	if (this.setting.rssdata) //if rss contents
		google.load("feeds", "1") //init google ajax api
	var slider=this
	jQuery(function($){ //on document.ready
		slider.$slider=$('#'+slider.setting.id)
		if (slider.setting.ajaxsource||slider.setting.rssdata)
			slider.$slider.empty()
		slider.addloadingpanel(jQuery, 'show')
		if (slider.setting.ajaxsource) //if ajax data
			slider.getajaxul(slider.setting.ajaxsource)
		else if (slider.setting.rssdata){ //if rss data
			slider.fetchfeeds()
		}
		else{ //if inline content
			if (slider.setting.inittype=="onload") //load scroller when page has completely loaded?
				$(window).load(function(){slider.init($)})
			else //load scroller immediately and get dimensions progressively instead
				slider.init($)
		}
	})
}

sagscroller.prototype={

	getajaxul:function(path){
		var $=jQuery, slider=this
		this.stopscroll() //stop animation/ scrolling of slider, in the event this is a subsequent call to getajaxul()
		this.$loadingpanel.show()
		$.ajax({
			url: path, //path to external content
			async: true,
			error:function(ajaxrequest){
				slider.$slider.html('Error fetching content.<br />Server Response: '+ajaxrequest.responseText)
			},
			success:function(content){
				slider.reloadul(content)
				if (slider.setting.refreshsecs>0) //refetch contents every x sec?
					setTimeout(function(){slider.getajaxul(path)}, slider.setting.refreshsecs*1000)
			}
		})
	},

	addloadingpanel:function($, mode){
		var loadingimgref=sagscroller_constants.loadingimg
		if (mode=="preload"){
			var loadingimg=new Image(loadingimgref.dimensions[0], loadingimgref.dimensions[1])
			loadingimg.src=loadingimgref.src
			this.$loadingimg=$(loadingimg).css({position:'absolute', zIndex:1003})
		}
		else{
			var sliderdimensions=[this.$slider.width(), this.$slider.height()]
			var $loadingpanel=$('<div />').css({position:'absolute', left:0, top:0, background:'black', opacity:0.5, width:sliderdimensions[0], height:sliderdimensions[1], zIndex:1002}).appendTo(this.$slider)
			this.$loadingimg.css({left:sliderdimensions[0]/2-loadingimgref.dimensions[0]/2, top:sliderdimensions[1]/2-loadingimgref.dimensions[1]/2}).appendTo(this.$slider)
			this.$loadingpanel=$loadingpanel.add(this.$loadingimg)
		}
	},

	addnavpanel:function(){
		var slider=this, setting=this.setting
		var $navpanel=$('<div class="sliderdesc"><div class="sliderdescbg"></div><div class="sliderdescfg"><div class="sliderdesctext"></div></div></div>')
			.css({position:'absolute', width:'100%', left:0, top:-1000, zIndex:'1001'})
			.find('div').css({position:'absolute', left:0, top:0, width:'100%'})
			.eq(0).css({background:sagscroller_constants.navpanel.background, opacity:sagscroller_constants.navpanel.opacity}).end() //"sliderdescbg" div
			.eq(1).css({color:'white'}).end() //"sliderdescfg" div
			.eq(2).css({textAlign:'center', cursor:'pointer', paddingTop:'2px'}).html('<img src="'+sagscroller_constants.navpanel.downarrow+'"/>').end().end()
			.appendTo(this.$slider)
		var $descpanel=$navpanel.find('div.sliderdesctext').attr('title', sagscroller_constants.navpanel.title).click(function(){ //action when nav bar is clicked on
			slider.stopscroll()
			slider.scrollmsg(setting.mode=="auto" && !setting.navpanel.cancelauto? true : false)
		})
		$navpanel.css({top:this.$slider.height()-parseInt(sagscroller_constants.navpanel.height), height:sagscroller_constants.navpanel.height}).find('div').css({height:'100%'})
	},

	resetuls:function(){ //function to swap between primary and secondary ul
		var $tempul=this.$mainul
		this.$mainul=this.$secul.css({zIndex:1000})
		this.$secul=$tempul.css({zIndex:999})
		this.$secul.css('top', this.ulheight)
	},

	reloadul:function(newhtml){ //function to empty out SAG scroller UL contents then reload with new contents
		this.$slider.find('ul').remove()
		this.ulheight=null
		this.curmsg=0;
		this.$slider.append(newhtml)
		this.init($)		
	},

	setgetoffset:function($li){
		var recaldimensions=(this.setting.ajaxsource || this.setting.rssdata) && this.setting.inittype=="onload" //bool to see if script should always refetch dimensions
		if (this.curmsg==this.$lis.length)
			return (!this.ulheight || recaldimensions)? this.ulheight=this.$mainul.height() : this.ulheight
		else{
			if (!$li.data('toppos') || recaldimensions)
				$li.data('toppos', $li.position().top)
			return $li.data('toppos')
		}
	},

	scrollmsg:function(repeat){
		var slider=this, setting=this.setting
		var ulheight=this.ulheight || this.$mainul.height()
		var endpoint=-this.setgetoffset(this.$lis.eq(this.curmsg))
		this.$mainul.animate({top: endpoint}, setting.animatespeed, function(){
			slider.curmsg=(slider.curmsg<slider.$lis.length+1)? slider.curmsg+1 : 0
			if (slider.curmsg==slider.$lis.length+1){ //if at end of UL
				slider.resetuls() //swap between main and sec UL
				slider.curmsg=1
			}
			if (repeat)
				slider.scrolltimer=setTimeout(function(){slider.scrollmsg(repeat)}, setting.pause)
		})
		var secendpoint=endpoint+ulheight
		this.$secul.animate({top: secendpoint}, setting.animatespeed)
	},

	stopscroll:function(){
		if (this.$mainul){
			this.$mainul.add(this.$secul).stop(true, false)
			clearTimeout(this.scrolltimer)
		}
	},

	init:function($){
		var setting=this.setting
		this.$loadingpanel.hide()
		this.$mainul=this.$slider.find('ul:eq(0)').css({zIndex:1000})
		this.$lis=this.$mainul.find('li')
		if (setting.navpanel.show)
			this.addnavpanel()
		this.$secul=this.$mainul.clone().css({top:this.$mainul.height(), zIndex:999}).appendTo(this.$slider) //create sec UL and add it to the end of main UL
		this.scrollmsg(setting.mode=="auto")
	},

	///////////////////////RSS related methods below///////////////////


	fetchfeeds:function(){
		var slider=this, rssdata=this.setting.rssdata
		this.stopscroll() //stop animation/ scrolling of slider, in the event this is a subsequent call to fetchfeeds()
		this.$loadingpanel.show()
		this.entries=[] //array holding combined RSS feeds' entries from Feed API (result.feed.entries)
		this.feedsfetched=0
		for (var i=0; i<rssdata.feeds.length; i++){ //loop through the specified RSS feeds' URLs
			var feedpointer=new google.feeds.Feed(rssdata.feeds[i][1]) //create new instance of Google Ajax Feed API
			feedpointer.setNumEntries(rssdata.entries) //set number of items to display
			feedpointer.load(function(label){
				return function(r){
					slider.storefeeds(r, label)
				}
			}(rssdata.feeds[i][0])) //call Feed.load() to retrieve and output RSS feed.
		}	
	},

	storefeeds:function(result, label){
		var thisfeed=(!result.error)? result.feed.entries : "" //get all feed entries as a JSON array or "" if failed
		if (thisfeed==""){ //if error has occured fetching feed
			alert("Google Feed API Error: "+result.error.message)
		}
		for (var i=0; i<thisfeed.length; i++){ //For each entry within feed
			result.feed.entries[i].label=label //extend it with a "label" property
		}
		this.entries=this.entries.concat(thisfeed) //add entry to array holding all feed entries
		this.feedsfetched+=1
		if (this.feedsfetched==this.setting.rssdata.feeds.length){ //if all feeds fetched
			if (this.setting.rssdata.groupbylabel){ //sort by label name?
				this.entries.sort(function(a,b){
					var fielda=a.label.toLowerCase(), fieldb=b.label.toLowerCase()
					return (fielda<fieldb)? -1 : (fielda>fieldb)? 1 : 0
				})
			}
			else{ //just sort by date
				this.entries.sort(function(a,b){return new Date(b.publishedDate)-new Date(a.publishedDate)})
			}
			this.formatfeeds()
		}
	},

	formatfeeds:function(){
		function formatdate(datestr, showoptions){
			var itemdate=new Date(datestr)
			var parseddate=(showoptions.indexOf("datetime")!=-1)? itemdate.toLocaleString() : (showoptions.indexOf("date")!=-1)? itemdate.toLocaleDateString() : ""
			return "<span class='datefield'>"+parseddate+"</span>"
		}
		var sagcontent='<ul>'
		var slider=this, rssdata=this.setting.rssdata, entries=this.entries
		for (var i=0; i<entries.length; i++){
			sagcontent+='<li><a href="'+entries[i].link+'" target="'+rssdata.linktarget+'">'+entries[i].title+'</a>'
				+'<div class="rsscontent">'
				+(/description/.test(rssdata.displayoptions)? entries[i].content : entries[i].contentSnippet)
				+'</div>'
				+'<div class="rsslabel">'
				+(/label/.test(rssdata.displayoptions)? "<b>Source("+(i+1)+"):</b> "+entries[i].label+" " : "")
				+(/date/.test(rssdata.displayoptions)? formatdate(entries[i].publishedDate, rssdata.displayoptions): "")
				+'</div>'
				+'</li>\n\n'
		}
	sagcontent+='</ul>'
	this.reloadul(sagcontent)
	if (slider.setting.refreshsecs>0) //refetch contents every x sec?
		setTimeout(function(){slider.fetchfeeds()}, slider.setting.refreshsecs*1000)
	}
}