//=============================
var ajaxpageclass = new Object();

ajaxpageclass.loadstatustext='<img src="{jquery}loading_bar.gif"/>';
ajaxpageclass.ajaxbustcache=false;
ajaxpageclass.paginatepersist=true; //enable persistence of last viewed pagination link (so reloading page doesn't reset page to 1)?
ajaxpageclass.pagerange=4; // Limit page links displayed to a specific number (useful if you have many pages in your book)?
ajaxpageclass.ellipse="..."; // Ellipse text (no HTML allowed)

/////////////// No need to edit beyond here /////////////////////////

ajaxpageclass.connect=function(pageurl, divId){
    var page_request = false;
    var bustcacheparameter="";
    if (window.XMLHttpRequest && !document.all) // if Mozilla, Safari etc (skip IE7, as object is buggy in that browser)
        page_request = new XMLHttpRequest()
    else if (window.ActiveXObject){ // if IE6 or below
        try {
            page_request = new ActiveXObject("Msxml2.XMLHTTP");
        }
        catch (e){
            try{
                page_request = new ActiveXObject("Microsoft.XMLHTTP");
            }
            catch (e){};
        }
    }
    else
        return false;
    document.getElementById(divId).innerHTML=this.loadstatustext; //Display "fetching page message"
    page_request.onreadystatechange=function(){
        ajaxpageclass.loadpage(page_request, divId);
    }
    if (this.ajaxbustcache) //if bust caching of external page
        bustcacheparameter=(pageurl.indexOf("?")!=-1)? "&"+new Date().getTime() : "?"+new Date().getTime();
    page_request.open('GET', pageurl+bustcacheparameter, true);
    page_request.send(null);
}

ajaxpageclass.loadpage=function(page_request, divId){
    if (page_request.readyState == 4 && (page_request.status==200 || window.location.href.indexOf("http")==-1)){
        document.getElementById(divId).innerHTML=page_request.responseText;
    }
}

ajaxpageclass.getCookie=function(Name){ 
    var re=new RegExp(Name+"=[^;]+", "i"); //construct RE to search for target name/value pair
    if (document.cookie.match(re)) //if cookie found
        return document.cookie.match(re)[0].split("=")[1]; //return its value
    return null;
}

ajaxpageclass.setCookie=function(name, value){
    document.cookie = name+"="+value;
}

ajaxpageclass.getInitialPage=function(divId, pageinfo){
    var persistedpage=this.getCookie(divId);
    var selectedpage=(this.paginatepersist && this.getCookie(divId)!=null)? parseInt(this.getCookie(divId)) : pageinfo.selectedpage;
    return (selectedpage>pageinfo.pages.length-1)? 0 : selectedpage; //check that selectedpage isn't out of range
}

ajaxpageclass.createBook=function(pageinfo, divId, paginateIds){ //MAIN CONSTRUCTOR FUNCTION
    this.pageinfo=pageinfo; //store object containing URLs of pages to fetch, selected page number etc
    this.divId=divId;
    this.paginateIds=paginateIds; //array of ids corresponding to the pagination DIVs defined for this pageinstance
    //NOTE: this.paginateInfo stores references to various components of each pagination DIV defined for this pageinstance
    //NOTE: Eg: divs[0] = 1st paginate div, pagelinks[0][0] = 1st page link within 1st paginate DIV, prevlink[0] = previous link within paginate DIV etc
    this.paginateInfo={
        divs:[],
        pagelinks:[[]],
        prevlink:[],
        nextlink:[],
        previouspage:null,
        previousrange:[null,null],
        leftellipse:[],
        rightellipse:[]
    }
    this.dopagerange=false;
    this.pagerangestyle='';
    this.ellipse='<span style="display:none">'+ajaxpageclass.ellipse+'</span>'; //construct HTML for ellipse
    var initialpage=ajaxpageclass.getInitialPage(divId, pageinfo);
    this.buildpagination(initialpage);
    this.selectpage(initialpage);
}

ajaxpageclass.createBook.prototype={

    buildpagination:function(selectedpage){ //build pagination links based on length of this.pageinfo.pages[]
        this.dopagerange=(this.pageinfo.pages.length>ajaxpageclass.pagerange); //Bool: enable limitpagerange if pagerange value is less than total pages available
        this.pagerangestyle=this.dopagerange? 'style="display:none"' : ''; //if limitpagerange enabled, hide pagination links when building them
        this.paginateInfo.previousrange=null; //Set previousrange[start, finish] to null to start
        if (this.pageinfo.pages.length<=1){ //no 0 or just 1 page
            document.getElementById(this.paginateIds[0]).innerHTML=(this.pageinfo.pages.length==1)? "Page 1 of 1" : "";
            return;
        }
        else{ //construct paginate interface
            var paginateHTML='<div class="pagination"><ul>\n'
            paginateHTML+='<li><a href="#previous" rel="'+(selectedpage-1)+'">Prev</a></li>\n'; //previous link HTML
            for (var i=0; i<this.pageinfo.pages.length; i++){
                var ellipses={
                    left: (i==0? this.ellipse : ''),
                    right: (i==this.pageinfo.pages.length-1? this.ellipse : '')
                } //if this is 1st or last page link, add ellipse next to them, hidden by default
                paginateHTML+='<li>'+ellipses.right+'<a href="#page'+(i+1)+'" rel="'+i+'" '+this.pagerangestyle+'>'+(i+1)+'</a>'+ellipses.left+'</li>\n';
            }
            paginateHTML+='<li><a href="#next" rel="'+(selectedpage+1)+'">Next</a></li>\n' //next link HTML
            paginateHTML+='</ul></div>'
        }// end construction
        this.paginateInfo.previouspage=selectedpage //remember last viewed page
        for (var i=0; i<this.paginateIds.length; i++){ //loop through # of pagination DIVs specified
            var paginatediv=document.getElementById(this.paginateIds[i]); //reference pagination DIV
            this.paginateInfo.divs[i]=paginatediv; //store ref to this paginate DIV
            paginatediv.innerHTML=paginateHTML;
            var paginatelinks=paginatediv.getElementsByTagName("a");
            var ellipsespans=paginatediv.getElementsByTagName("span");
            this.paginateInfo.prevlink[i]=paginatelinks[0];
            if (paginatelinks.length>0)
                this.paginateInfo.nextlink[i]=paginatelinks[paginatelinks.length-1];
            this.paginateInfo.leftellipse[i]=ellipsespans[0];
            this.paginateInfo.rightellipse[i]=ellipsespans[1];
            this.paginateInfo.pagelinks[i]=[]; //array to store the page links of pagination DIV
            for (var p=1; p<paginatelinks.length-1; p++){
                this.paginateInfo.pagelinks[i][p-1]=paginatelinks[p];
            }
            var pageinstance=this;
            paginatediv.onclick=function(e){
                var targetobj=window.event? window.event.srcElement : e.target
                if (targetobj.tagName=="A" && targetobj.getAttribute("rel")!=""){
                    if (!/disabled/i.test(targetobj.className)){ //if this pagination link isn't disabled (CSS classname "disabled")
                        pageinstance.selectpage(parseInt(targetobj.getAttribute("rel")));
                    }
                }
                return false;
            }
        }
    },

    selectpage:function(selectedpage){
        //replace URL's root domain with dynamic root domain (with or without "www"), for ajax security sake:
        if (this.pageinfo.pages.length>0){
            var ajaxfriendlyurl=this.pageinfo.pages[selectedpage].replace(/^http:\/\/[^\/]+\//i, "http://"+window.location.hostname+"/");
            ajaxpageclass.connect(ajaxfriendlyurl, this.divId); //fetch requested page and display it inside DIV
        }
        if (this.pageinfo.pages.length<=1) //if this book only contains only 1 page (or 0)
            return //stop here
        var paginateInfo=this.paginateInfo
        for (var i=0; i<paginateInfo.divs.length; i++){ //loop through # of pagination DIVs specified
            //var paginatediv=document.getElementById(this.paginateIds[i])
            paginateInfo.prevlink[i].className=(selectedpage==0)? "prevnext disabled" : "prevnext"; //if current page is 1st page, disable "prev" button
            paginateInfo.prevlink[i].setAttribute("rel", selectedpage-1); //update rel attr of "prev" button with page # to go to when clicked on
            paginateInfo.nextlink[i].className=(selectedpage==this.pageinfo.pages.length-1)? "prevnext disabled" : "prevnext";
            paginateInfo.nextlink[i].setAttribute("rel", selectedpage+1);
            paginateInfo.pagelinks[i][paginateInfo.previouspage].className="";//deselect last clicked on pagination link (previous)
            paginateInfo.pagelinks[i][selectedpage].className="currentpage"; //select current pagination link
        }
        paginateInfo.previouspage=selectedpage; //Update last viewed page info
        ajaxpageclass.setCookie(this.divId, selectedpage);
        this.limitpagerange(selectedpage); //limit range of page links displayed (if applicable)
    },

    limitpagerange:function(selectedpage){
        //reminder: selectedpage count starts at 0 (0=1st page)
        var paginateInfo=this.paginateInfo;
        if (this.dopagerange){
            var visiblelinks=ajaxpageclass.pagerange-1; //# of visible page links other than currently selected link
            var visibleleftlinks=Math.floor(visiblelinks/2); //calculate # of visible links to the left of the selected page
            var visiblerightlinks=visibleleftlinks+(visiblelinks%2==1? 1 : 0); //calculate # of visible links to the right of the selected page
            if (selectedpage<visibleleftlinks){ //if not enough room to the left to accomodate all visible left links
                var overage=visibleleftlinks-selectedpage;
                visibleleftlinks-=overage; //remove overage links from visible left links
                visiblerightlinks+=overage; //add overage links to the visible right links
            }
            else if ((this.pageinfo.pages.length-selectedpage-1)<visiblerightlinks){ //else if not enough room to the left to accomodate all visible right links
                var overage=visiblerightlinks-(this.pageinfo.pages.length-selectedpage-1);
                visiblerightlinks-=overage; //remove overage links from visible right links
                visibleleftlinks+=overage; //add overage links to the visible left links
            }
            var currentrange=[selectedpage-visibleleftlinks, selectedpage+visiblerightlinks]; //calculate indices of visible pages to show: [startindex, endindex]
            var previousrange=paginateInfo.previousrange; //retrieve previous page range
            for (var i=0; i<paginateInfo.divs.length; i++){ //loop through paginate divs
                if (previousrange){ //if previous range is available (not null)
                    for (var p=previousrange[0]; p<=previousrange[1]; p++){ //hide all page links
                        paginateInfo.pagelinks[i][p].style.display="none";
                    }
                }
                for (var p=currentrange[0]; p<=currentrange[1]; p++){ //reveal all active page links
                    paginateInfo.pagelinks[i][p].style.display="inline";
                }
                paginateInfo.pagelinks[i][0].style.display="inline"; //always show 1st page link
                paginateInfo.pagelinks[i][this.pageinfo.pages.length-1].style.display="inline"; //always show last page link
                paginateInfo.leftellipse[i].style.display=(currentrange[0]>1)? "inline" : "none"; //if starting page is page3 or higher, show ellipse to page1
                paginateInfo.rightellipse[i].style.display=(currentrange[1]<this.pageinfo.pages.length-2)? "inline" : "none"; //if end page is 2 pages before last page or less, show ellipse to last page
            }
        }
        paginateInfo.previousrange=currentrange;
    },

    refresh:function(pageinfo){
        this.pageinfo=pageinfo;
        var initialpage=ajaxpageclass.getInitialPage(this.divId, pageinfo);
        this.buildpagination(initialpage);
        this.selectpage(initialpage);
    }
}