/*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:'/aasn/images/down.gif', opacity:0.6, title:'Go to Next Content'},
  loadingimg: {src:'/aasn/images/ajaxloading.gif', dimensions:[100,15]}
}

function sagscroller(options){

  this.setting={mode:'manual', inittype:'stunted', pause:3000, animatespeed:700, 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)
  }
}