Synnefo

/**

 * This jQuery plugin displays pagination links inside the selected elements.

 * 

 * This plugin needs at least jQuery 1.4.2

 *

 * @author Gabriel Birke (birke *at* d-scribe *dot* de)

 * @version 2.2

 * @param {int} maxentries Number of entries to paginate

 * @param {Object} opts Several options (see README for documentation)

 * @return {Object} jQuery Object

 */

 (function($){

        /**

         * @class Class for calculating pagination values

         */

        $.PaginationCalculator = function(maxentries, opts) {

                this.maxentries = maxentries;

                this.opts = opts;

        }

        $.extend($.PaginationCalculator.prototype, {

                /**

                 * Calculate the maximum number of pages

                 * @method

                 * @returns {Number}

                 */

                numPages:function() {

                        return Math.ceil(this.maxentries/this.opts.items_per_page);

                },

                /**

                 * Calculate start and end point of pagination links depending on 

                 * current_page and num_display_entries.

                 * @returns {Array}

                 */

                getInterval:function(current_page)  {

                        var ne_half = Math.floor(this.opts.num_display_entries/2);

                        var np = this.numPages();

                        var upper_limit = np - this.opts.num_display_entries;

                        var start = current_page > ne_half ? Math.max( Math.min(current_page - ne_half, upper_limit), 0 ) : 0;

                        var end = current_page > ne_half?Math.min(current_page+ne_half + (this.opts.num_display_entries % 2), np):Math.min(this.opts.num_display_entries, np);

                        return {start:start, end:end};

                }

        });

        // Initialize jQuery object container for pagination renderers

        $.PaginationRenderers = {}

        /**

         * @class Default renderer for rendering pagination links

         */

        $.PaginationRenderers.defaultRenderer = function(maxentries, opts) {

                this.maxentries = maxentries;

                this.opts = opts;

                this.pc = new $.PaginationCalculator(maxentries, opts);

        }

        $.extend($.PaginationRenderers.defaultRenderer.prototype, {

                /**

                 * Helper function for generating a single link (or a span tag if it's the current page)

                 * @param {Number} page_id The page id for the new item

                 * @param {Number} current_page 

                 * @param {Object} appendopts Options for the new item: text and classes

                 * @returns {jQuery} jQuery object containing the link

                 */

                createLink:function(page_id, current_page, appendopts){

                        var lnk, np = this.pc.numPages();

                        page_id = page_id<0?0:(page_id<np?page_id:np-1); // Normalize page id to sane value

                        appendopts = $.extend({text:page_id+1, classes:""}, appendopts||{});

                        if(page_id == current_page){

                                lnk = $("<span class='current'>" + appendopts.text + "</span>");

                        }

                        else

                        {

                                lnk = $("<a>" + appendopts.text + "</a>")

                                        .attr('href', this.opts.link_to.replace(/__id__/,page_id));

                        }

                        if(appendopts.classes){ lnk.addClass(appendopts.classes); }

                        lnk.data('page_id', page_id);

                        return lnk;

                },

                // Generate a range of numeric links 

                appendRange:function(container, current_page, start, end, opts) {

                        var i;

                        for(i=start; i<end; i++) {

                                this.createLink(i, current_page, opts).appendTo(container);

                        }

                },

                getLinks:function(current_page, eventHandler) {

                        var begin, end,

                                interval = this.pc.getInterval(current_page),

                                np = this.pc.numPages(),

                                fragment = $("<div class='pagination'></div>");

                        // Generate "Previous"-Link

                        if(this.opts.prev_text && (current_page > 0 || this.opts.prev_show_always)){

                                fragment.append(this.createLink(current_page-1, current_page, {text:this.opts.prev_text, classes:"prev"}));

                        }

                        // Generate starting points

                        if (interval.start > 0 && this.opts.num_edge_entries > 0)

                        {

                                end = Math.min(this.opts.num_edge_entries, interval.start);

                                this.appendRange(fragment, current_page, 0, end, {classes:'sp'});

                                if(this.opts.num_edge_entries < interval.start && this.opts.ellipse_text)

                                {

                                        jQuery("<span>"+this.opts.ellipse_text+"</span>").appendTo(fragment);

                                }

                        }

                        // Generate interval links

                        this.appendRange(fragment, current_page, interval.start, interval.end);

                        // Generate ending points

                        if (interval.end < np && this.opts.num_edge_entries > 0)

                        {

                                if(np-this.opts.num_edge_entries > interval.end && this.opts.ellipse_text)

                                {

                                        jQuery("<span>"+this.opts.ellipse_text+"</span>").appendTo(fragment);

                                }

                                begin = Math.max(np-this.opts.num_edge_entries, interval.end);

                                this.appendRange(fragment, current_page, begin, np, {classes:'ep'});

                        }

                        // Generate "Next"-Link

                        if(this.opts.next_text && (current_page < np-1 || this.opts.next_show_always)){

                                fragment.append(this.createLink(current_page+1, current_page, {text:this.opts.next_text, classes:"next"}));

                        }

                        $('a', fragment).click(eventHandler);

                        return fragment;

                }

        });

        // Extend jQuery

        $.fn.pagination = function(maxentries, opts){

                // Initialize options with default values

                opts = jQuery.extend({

                        items_per_page:10,

                        num_display_entries:11,

                        current_page:0,

                        num_edge_entries:0,

                        link_to:"#",

                        prev_text:"Prev",

                        next_text:"Next",

                        ellipse_text:"...",

                        prev_show_always:true,

                        next_show_always:true,

                        renderer:"defaultRenderer",

                        load_first_page:false,

                        callback:function(){return false;}

                },opts||{});

                var containers = this,

                        renderer, links, current_page;

                /**

                 * This is the event handling function for the pagination links. 

                 * @param {int} page_id The new page number

                 */

                function paginationClickHandler(evt){

                        var links, 

                                new_current_page = $(evt.target).data('page_id'),

                                continuePropagation = selectPage(new_current_page);

                        if (!continuePropagation) {

                                evt.stopPropagation();

                        }

                        return continuePropagation;

                }

                /**

                 * This is a utility function for the internal event handlers. 

                 * It sets the new current page on the pagination container objects, 

                 * generates a new HTMl fragment for the pagination links and calls

                 * the callback function.

                 */

                function selectPage(new_current_page) {

                        // update the link display of a all containers

                        containers.data('current_page', new_current_page);

                        links = renderer.getLinks(new_current_page, paginationClickHandler);

                        containers.empty();

                        links.appendTo(containers);

                        // call the callback and propagate the event if it does not return false

                        var continuePropagation = opts.callback(new_current_page, containers);

                        return continuePropagation;

                }

                // -----------------------------------

                // Initialize containers

                // -----------------------------------

                current_page = opts.current_page;

                containers.data('current_page', current_page);

                // Create a sane value for maxentries and items_per_page

                maxentries = (!maxentries || maxentries < 0)?1:maxentries;

                opts.items_per_page = (!opts.items_per_page || opts.items_per_page < 0)?1:opts.items_per_page;

                if(!$.PaginationRenderers[opts.renderer])

                {

                        throw new ReferenceError("Pagination renderer '" + opts.renderer + "' was not found in jQuery.PaginationRenderers object.");

                }

                renderer = new $.PaginationRenderers[opts.renderer](maxentries, opts);

                // Attach control events to the DOM elements

                var pc = new $.PaginationCalculator(maxentries, opts);

                var np = pc.numPages();

                containers.bind('setPage', {numPages:np}, function(evt, page_id) { 

                                if(page_id >= 0 && page_id < evt.data.numPages) {

                                        selectPage(page_id); return false;

                                }

                });

                containers.bind('prevPage', function(evt){

                                var current_page = $(this).data('current_page');

                                if (current_page > 0) {

                                        selectPage(current_page - 1);

                                }

                                return false;

                });

                containers.bind('nextPage', {numPages:np}, function(evt){

                                var current_page = $(this).data('current_page');

                                if(current_page < evt.data.numPages - 1) {

                                        selectPage(current_page + 1);

                                }

                                return false;

                });

                // When all initialisation is done, draw the links

                links = renderer.getLinks(current_page, paginationClickHandler);

                containers.empty();

                links.appendTo(containers);

                // call callback function

                if(opts.load_first_page) {

                        opts.callback(current_page, containers);

                }

        } // End of $.fn.pagination block

})(jQuery);