/**
 * This jQuery plugin displays pagination links inside the selected elements.
 *
 * @author Gabriel Birke (birke *at* d-scribe *dot* de)
 * @version 1.2
 * @param {int} maxentries Number of entries to paginate
 * @param {Object} opts Several options (see README for documentation)
 * @return {Object} jQuery Object
 */
jQuery.fn.pagination = function(maxentries, opts){
    opts = jQuery.extend({
        items_per_page: 10,
        num_display_entries: 10,
        current_page: 0,
        num_edge_entries: 0,
        link_to: "#",
        prev_text: "«",
        next_text: "»",
        ellipse_text: "...",
        prev_show_always: true,
        next_show_always: true,
        callback: function(){
            return false;
        }
    }, opts ||
    {});
    
    return this.each(function(){
        /**
         * Calculate the maximum number of pages
         */
        function numPages(){
            return Math.ceil(maxentries / opts.items_per_page);
        }
        
        /**
         * Calculate start and end point of pagination links depending on
         * current_page and num_display_entries.
         * @return {Array}
         */
        function getInterval(){
            var ne_half = Math.ceil(opts.num_display_entries / 2);
            var np = numPages();
            var upper_limit = np - 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, np) : Math.min(opts.num_display_entries, np);
            return [start, end];
        }
        
        /**
         * This is the event handling function for the pagination links.
         * @param {int} page_id The new page number
         */
        function pageSelected(page_id, evt){
            current_page = page_id;
            drawLinks();
            var continuePropagation = opts.callback(page_id, panel);
            if (!continuePropagation) {
                if (evt.stopPropagation) {
                    evt.stopPropagation();
                }
                else {
                    evt.cancelBubble = true;
                }
            }
            return continuePropagation;
        }
        
        /**
         * This function inserts the pagination links into the container element
         */
        function drawLinks(){
            panel.empty();
            var interval = getInterval();
            var np = numPages();
            // This helper function returns a handler function that calls pageSelected with the right page_id
            var getClickHandler = function(page_id){
                return function(evt){
                    return pageSelected(page_id, evt);
                }
            }
            // Helper function for generating a single link (or a span tag if it's the current page)
            var appendItem = function(page_id, appendopts){
                page_id = page_id < 0 ? 0 : (page_id < np ? page_id : np - 1); // Normalize page id to sane value
                appendopts = jQuery.extend({
                    text: page_id + 1,
                    classes: ""
                }, appendopts ||
                {});
                if (page_id == current_page) {
                    var lnk = jQuery("<span class='current'>" + (appendopts.text) + "</span>");
                }
                else {
                    var lnk = jQuery("<a>" + (appendopts.text) + "</a>").bind("click", getClickHandler(page_id)).attr('href', opts.link_to.replace(/__id__/, page_id));
                    
                    
                }
                if (appendopts.classes) {
                    lnk.addClass(appendopts.classes);
                }
                panel.append(lnk);
            }
            // Generate "Previous"-Link
            if (opts.prev_text && (current_page > 0 || opts.prev_show_always)) {
                appendItem(current_page - 1, {
                    text: opts.prev_text,
                    classes: "pagination_prev"
                });
            }
            // Generate starting points
            if (interval[0] > 0 && opts.num_edge_entries > 0) {
                var end = Math.min(opts.num_edge_entries, interval[0]);
                for (var i = 0; i < end; i++) {
                    appendItem(i);
                }
                if (opts.num_edge_entries < interval[0] && opts.ellipse_text) {
                    jQuery("<span>" + opts.ellipse_text + "</span>").appendTo(panel);
                }
            }
            // Generate interval links
            for (var i = interval[0]; i < interval[1]; i++) {
                appendItem(i);
            }
            // Generate ending points
            if (interval[1] < np && opts.num_edge_entries > 0) {
                if (np - opts.num_edge_entries > interval[1] && opts.ellipse_text) {
                    jQuery("<span>" + opts.ellipse_text + "</span>").appendTo(panel);
                }
                var begin = Math.max(np - opts.num_edge_entries, interval[1]);
                for (var i = begin; i < np; i++) {
                    appendItem(i);
                }
                
            }
            // Generate "Next"-Link
            if (opts.next_text && (current_page < np - 1 || opts.next_show_always)) {
                appendItem(current_page + 1, {
                    text: opts.next_text,
                    classes: "pagination_next"
                });
            }
        }
        
        // Extract current_page from options
        var current_page = opts.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;
        // Store DOM element for easy access from all inner functions
        var panel = jQuery(this);
        // Attach control functions to the DOM element 
        this.selectPage = function(page_id){
            pageSelected(page_id);
        }
        this.prevPage = function(){
            if (current_page > 0) {
                pageSelected(current_page - 1);
                return true;
            }
            else {
                return false;
            }
        }
        this.nextPage = function(){
            if (current_page < numPages() - 1) {
                pageSelected(current_page + 1);
                return true;
            }
            else {
                return false;
            }
        }
        // When all initialisation is done, draw the links
        drawLinks();
        // call callback function
        opts.callback(current_page, this);
    });
}

/**
 * Callback function that displays the content.
 *
 * Gets called every time the user clicks on a pagination link.
 *
 * @param {int}page_index New Page index
 * @param {jQuery} jq the container with the pagination links as a jQuery object
 */
function pageselectCallback(page_index, jq){
    scroll(0, 0);
    
    // Get number of elements per pagionation page from form
    var items_per_page = 2
    var num_entries = $('div.component_2d_2').length;
    var max_elem = Math.min((page_index + 1) * items_per_page, num_entries);
    
    /////////
    
    $('div.component_2d_2').css("display", "none");
    
    for (var i = page_index * items_per_page; i < max_elem; i++) {
        $('div.component_2d_2:eq(' + i + ')').show();
    }
    
    scroll(0, 0);
    
    // Prevent click eventpropagation
    
    return false;
}


function getOptionsFromForm(){
    var num_entries = $('div.component_2d_2').length * 10 / 2;
    var initial_page = anchoredPage(2, num_entries);
    var opt = {
        callback: pageselectCallback
    };
    opt.current_page = initial_page;
    return opt;
}

function anchoredPage(items_per_page){

    var element
    var page
    var num_entries = $('div.component_2d_2').length;
    
    if (document.location.hash) {
        var hashQueryString = document.location.hash;
        hashQueryString = hashQueryString.replace("#", "");
		hashQueryString = hashQueryString.replace("%20", " ");
        
        for (var i = 0; i < num_entries; i++) {
            if (hashQueryString == $('div.component_2d_2:eq(' + i + ') h1 a').attr("name")) {
                page = i
                break;
            }
        }
        return (page / items_per_page);
        
    }
    else {
        return 0;
    }
    
}

history.navigationMode = 'compatible';

// When document has loaded, initialize pagination and form 
$(document).ready(function(){
    
    var num_entries = $('div.component_2d_2').length * 10 / 2;
    var optInit = getOptionsFromForm();
    $("#pagination").pagination(num_entries, optInit);
    
});