// -------------------------------------------------------------------
// Virtual Pagination Script- By Dynamic Drive, available at: http://www.dynamicdrive.com
// Last updated: Nov 21st, 2008 to v2.0
// ** Adds ability to define multiple pagination DIVs (the secondary DIVs mirror primary DIV's contents)
// ** Last viewed page persistence, so last viewed page can be remembered/ recalled within browser session.
// ** Improvements to instance.navigate() to select a page using an arbitrary link or inside another script.
// ** Ability to select a page using a URL parameter (ie: target.htm?virtualpiececlass=index).
//
// PUBLIC: virtualpaginate()
// Main Virtual Paginate Object function.
// -------------------------------------------------------------------

document.write('<style type="text/css">' //write out CSS for class ".hidepeice" that hides pieces of contents within pages
    + '.hidepiece{display:none}\n'
    + '@media print{.hidepiece{display:block !important;}}\n'
    + '</style>');

function virtualpaginate(config) { //config: {piececlass:, piececontainer:, pieces_per_page:, defaultpage:, persist}
    this.piececlass = config.piececlass;
    var elementType = (typeof config.piececontainer == "undefined") ? "div" : config.piececontainer; //The type of element used to divide up content into pieces. Defaults to "div"
    this.pieces = virtualpaginate.collectElementbyClass(config.piececlass, elementType); //get total number of divs matching class name
    //Set this.chunksize: 1 if "chunksize" param is undefined, "chunksize" if it's less than total pieces available, or simply total pieces avail (show all)
    this.chunksize = (typeof config.pieces_per_page == "undefined") ? 1 : (config.pieces_per_page > 0 && config.pieces_per_page < this.pieces.length) ? config.pieces_per_page : this.pieces.length;
    this.pagecount = Math.ceil(this.pieces.length / this.chunksize); //calculate number of "pages" needed to show the divs
    this.paginatediv = [], this.flatviewlinks = [], this.cpspan = [], this.selectmenu = [];
    this.persist = config.persist;
    var persistedpage = virtualpaginate.getCookie("dd_" + this.piececlass) || 0;
    var urlselectedpage = virtualpaginate.urlparamselect(this.piececlass); //returns null or index from: mypage.htm?piececlass=index
    this.currentpage = (typeof urlselectedpage == "number") ? urlselectedpage : ((this.persist) ? persistedpage : config.defaultpage);
    this.currentpage = (this.currentpage < this.pagecount) ? parseInt(this.currentpage) : 0; //ensure currentpage is within range of available pages
    this.showpage(this.currentpage); //Show selected page
}

// -------------------------------------------------------------------
// PUBLIC: navigate(keyword)- Calls this.showpage() based on parameter passed (0=page1, 1=page2 etc, "next", "first", or "last")
// -------------------------------------------------------------------

virtualpaginate.prototype.navigate = function(keyword) {
    var prevlinkindex = this.currentpage; //Get index of last clicked on page
    if (keyword == "previous")
        this.currentpage = (this.currentpage > 0) ? this.currentpage - 1 : (this.currentpage == 0) ? this.pagecount - 1 : 0;
    else if (keyword == "next")
        this.currentpage = (this.currentpage < this.pagecount - 1) ? this.currentpage + 1 : 0;
    else if (keyword == "first")
        this.currentpage = 0;
    else if (keyword == "last")
        this.currentpage = this.pagecount - 1; 
//last page number
    else
        this.currentpage = parseInt(keyword);
    this.currentpage = (this.currentpage < this.pagecount) ? this.currentpage : 0; //ensure pagenumber is within range of available pages
    this.showpage(this.currentpage);
    for (var p = 0; p < this.paginatediv.length; p++) { //loop through all pagination DIVs
        if (this.flatviewpresent)
            this.flatviewlinks[p][prevlinkindex].className = ""; //"Unhighlight" previous page (before this.currentpage increments)
        if (this.selectmenupresent)
            this.selectmenu[p].selectedIndex = this.currentpage;
        if (this.flatviewpresent)
            this.flatviewlinks[p][this.currentpage].className = "selected"; //"Highlight" current page
    }
};
// -------------------------------------------------------------------
// PUBLIC: buildpagination()- Create pagination interface by calling one or more of the paginate_build_() functions
// -------------------------------------------------------------------

virtualpaginate.prototype.buildpagination = function(divids, optnavtext) {
    var divids = (typeof divids == "string") ? [divids] : divids; //force divids to be an array of ids
    var primarypaginatediv = divids.shift(); //get first id within divids[]
    var paginaterawHTML = document.getElementById(primarypaginatediv).innerHTML;
    this.paginate_build(primarypaginatediv, 0, optnavtext);
    for (var i = 0; i < divids.length; i++) {
        document.getElementById(divids[i]).innerHTML = paginaterawHTML;
        this.paginate_build(divids[i], i + 1, optnavtext);
    }
};
// -------------------------------------------------------------------
// PRIVATE utility functions
// -------------------------------------------------------------------

virtualpaginate.collectElementbyClass = function(classname, element) { //Returns an array containing DIVs with specified classname
    if (document.querySelectorAll) {
        var pieces = document.querySelectorAll(element + "." + classname); //return pieces as HTMLCollection
    } else {
        var classnameRE = new RegExp("(^|\\s+)" + classname + "($|\\s+)", "i"); //regular expression to screen for classname within element
        var pieces = [];
        var alltags = document.getElementsByTagName(element);
        for (var i = 0; i < alltags.length; i++) {
            if (typeof alltags[i].className == "string" && alltags[i].className.search(classnameRE) != -1)
                pieces[pieces.length] = alltags[i]; //return pieces as array
        }
    }
    return pieces;
};
virtualpaginate.urlparamselect = function(vpclass) {
    var result = window.location.search.match(new RegExp(vpclass + "=(\\d+)", "i")); //check for "?piececlass=2" in URL
    return (result == null) ? null : parseInt(RegExp.$1); //returns null or index, where index (int) is the selected virtual page's index
};
virtualpaginate.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;
};
virtualpaginate.setCookie = function(name, value) {
    document.cookie = name + "=" + value;
};
// -------------------------------------------------------------------
// PRIVATE: showpage(pagenumber)- Shows a page based on parameter passed (0=page1, 1=page2 etc)
// -------------------------------------------------------------------

virtualpaginate.prototype.showpage = function(pagenumber) {
    var totalitems = this.pieces.length; //total number of broken up divs
    var showstartindex = pagenumber * this.chunksize; //array index of div to start showing per pagenumber setting
    var showendindex = showstartindex + this.chunksize - 1; //array index of div to stop showing after per pagenumber setting
    for (var i = 0; i < totalitems; i++) {
        if (i >= showstartindex && i <= showendindex)
            this.pieces[i].style.display = "block";
        else
            this.pieces[i].style.display = "none";
    }
    if (this.persist) { //if persistence enabled
        virtualpaginate.setCookie("dd_" + this.piececlass, this.currentpage);
    }
    if (this.cpspan.length > 0) { //if <span class="paginateinfo> element is present, update it with the most current info (ie: Page 3/4)
        for (var p = 0; p < this.cpspan.length; p++)
            this.cpspan[p].innerHTML = 'Page ' + (this.currentpage + 1) + '/' + this.pagecount;
    }
};
// -------------------------------------------------------------------
// PRIVATE: build() methods- Various methods to create pagination interfaces
// paginate_paginate_build()- Main build() paginate function
// paginate_output_flatview()- Accepts <span class="flatview"> element and populates it with sequential pagination links
// paginate_paginate_build_flatview()- Parses the modified <span class="flatview"> element and assigns click behavior to the pagination links
// paginate_build_selectmenu(paginatedropdown)- Accepts an empty SELECT element and turns it into pagination menu
// paginate_build_regularlinks(paginatelinks)- Accepts a collection of links and screens out/ creates pagination out of ones with specific "rel" attr
// paginate_build_cpinfo(cpspan)- Accepts <span class="paginateinfo"> element and displays current page info (ie: Page 1/4)
// -------------------------------------------------------------------

virtualpaginate.prototype.paginate_build = function(divid, divpos, optnavtext) {
    var instanceOfBox = this;
    var paginatediv = document.getElementById(divid);
    if (this.chunksize == this.pieces.length) { //if user has set to display all pieces at once, no point in creating pagination div
        paginatediv.style.display = "none";
        return;
    }
    var paginationcode = paginatediv.innerHTML; //Get user defined, "unprocessed" HTML within paginate div
    if (paginatediv.getElementsByTagName("select").length > 0) //if there's a select menu in div
        this.paginate_build_selectmenu(paginatediv.getElementsByTagName("select")[0], divpos, optnavtext);
    if (paginatediv.getElementsByTagName("a").length > 0) //if there are links defined in div
        this.paginate_build_regularlinks(paginatediv.getElementsByTagName("a"));
    var allspans = paginatediv.getElementsByTagName("span"); //Look for span tags within passed div
    for (var i = 0; i < allspans.length; i++) {
        if (allspans[i].className == "flatview")
            this.paginate_output_flatview(allspans[i], divpos, optnavtext);
        else if (allspans[i].className == "paginateinfo")
            this.paginate_build_cpinfo(allspans[i], divpos);
    }
    this.paginatediv[divpos] = paginatediv;
};
virtualpaginate.prototype.paginate_output_flatview = function(flatviewcontainer, divpos, anchortext) {
    var flatviewhtml = "";
    var anchortext = anchortext || new Array();
    for (var i = 0; i < this.pagecount; i++) {
        if (typeof anchortext[i] != "undefined") //if custom anchor text for this link exists
            flatviewhtml += '<a href="#flatview" rel="' + i + '">' + anchortext[i] + '</a> '; 
//build pagination link using custom anchor text
        else
            flatviewhtml += '<a href="#flatview" rel="' + i + '">' + (i + 1) + '</a> '; //build  pagination link using auto incremented sequential number instead
    }
    flatviewcontainer.innerHTML = flatviewhtml;
    this.paginate_build_flatview(flatviewcontainer, divpos, anchortext);
};
virtualpaginate.prototype.paginate_build_flatview = function(flatviewcontainer, divpos, anchortext) {
    var instanceOfBox = this;
    var flatviewhtml = "";
    this.flatviewlinks[divpos] = flatviewcontainer.getElementsByTagName("a");
    for (var i = 0; i < this.flatviewlinks[divpos].length; i++) {
        this.flatviewlinks[divpos][i].onclick = function() {
            var prevlinkindex = instanceOfBox.currentpage; //Get index of last clicked on flatview link
            var curlinkindex = parseInt(this.getAttribute("rel"));
            instanceOfBox.navigate(curlinkindex);
            return false;
        };
    }
    this.flatviewlinks[divpos][this.currentpage].className = "selected"; //"Highlight" current flatview link
    this.flatviewpresent = true; //indicate flat view links are present
};
virtualpaginate.prototype.paginate_build_selectmenu = function(paginatedropdown, divpos, anchortext) {
    var instanceOfBox = this;
    var anchortext = anchortext || new Array();
    this.selectmenupresent = 1;
    for (var i = 0; i < this.pagecount; i++) {
        if (typeof anchortext[i] != "undefined") //if custom anchor text for this link exists, use anchor text as each OPTION's text
            paginatedropdown.options[i] = new Option(anchortext[i], i);
        else //else, use auto incremented, sequential numbers
            paginatedropdown.options[i] = new Option("Page " + (i + 1) + " of " + this.pagecount, i);
    }
    paginatedropdown.selectedIndex = this.currentpage;
    setTimeout(function() { paginatedropdown.selectedIndex = instanceOfBox.currentpage; }, 500); //refresh currently selected option (for IE's sake)
    paginatedropdown.onchange = function() {
        instanceOfBox.navigate(this.selectedIndex);
    };
    this.selectmenu[divpos] = paginatedropdown;
    this.selectmenu[divpos].selectedIndex = this.currentpage; //"Select" current page's corresponding option
};
virtualpaginate.prototype.paginate_build_regularlinks = function(paginatelinks) {
    var instanceOfBox = this;
    for (var i = 0; i < paginatelinks.length; i++) {
        var currentpagerel = paginatelinks[i].getAttribute("rel");
        if (currentpagerel == "previous" || currentpagerel == "next" || currentpagerel == "first" || currentpagerel == "last") { //screen for these "rel" values
            paginatelinks[i].onclick = function() {
                instanceOfBox.navigate(this.getAttribute("rel"));
                return false;
            };
        }
    }
};
virtualpaginate.prototype.paginate_build_cpinfo = function(cpspan, divpos) {
    this.cpspan[divpos] = cpspan;
    cpspan.innerHTML = 'Page ' + (this.currentpage + 1) + '/' + this.pagecount;
};