/**
 * This jQuery plugin displays pagination links inside the selected elements.
 *
 * @author Gabriel Birke (birke *at* d-scribe *dot* de), modified by Sapient for DVI
 * @version 1.1
 * @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:12,
		num_display_entries:0,
		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,
		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);
			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() {
			var interval = getInterval();
			var np = numPages();
			panel.find("a").unbind("click");
			
			// 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 updateItem = 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, act:"prev"}, appendopts||{});
				var lnk = panel.find("a."+appendopts.act);
				lnk.unbind("click");
				if(page_id == current_page){
					lnk.addClass("disabled "+appendopts.act+"-disabled");
				}
				else
				{
					lnk.removeClass("disabled prev-disabled next-disabled")
             		   .bind("click", function(evt) {
             					$(this).blur();
             					getClickHandler(page_id)(evt);
             					return false;
             				});
				}
			}
			
			// Generate "Previous"-Link
			if(opts.prev_text && (current_page > 0 || opts.prev_show_always)){
		        updateItem(current_page-1,{text:opts.prev_text, act:"prev"});
			}
		
		    // Update select options
		    var sel = panel.find("select");
			sel.empty();
			var groupSizeMultiple = 25; /* Group size must be a multiple of this number */
			var groupSize = Math.round((Math.sqrt(np)/groupSizeMultiple))*groupSizeMultiple || groupSizeMultiple;
			for (var i = 0; i < np; i++) {
				if (np > 100 && np > groupSize+Math.floor(groupSize*0.1)) {
					if (i%groupSize===0 && (i < current_page-current_page%groupSize || i >= current_page-current_page%groupSize+groupSize)) {
						sel.append($("<option/>").attr("value", i).text((i+1)+" - "+(i+groupSize>np?np:i+groupSize)));
						continue;
					}
					if (i >= current_page-current_page%groupSize && i < current_page-current_page%groupSize+groupSize) {
						if (i%groupSize===0) { sel.append($("<optgroup/>").attr("label", (i+1)+" - "+(i+groupSize>np?np:i+groupSize))); }
						sel.find("optgroup").append(
						  $("<option/>").attr(i===current_page?{value:i,selected:"selected"}:{value:i}).text(i+1)
						);
					}
				}
				else { sel.append($("<option/>").attr(i===current_page?{value:i,selected:"selected"}:{value:i}).text(i+1)); }
			}
		    sel.attr("disabled", false).unbind("change")
		       .bind("change", function(evt) {
		         $(this).blur();
		         $(this).parents(".resultSection").find(".pagination select").attr("disabled", true);
		         $(this).parents(".resultSection").find(".pagination a").unbind("click");
		         //$(this).parents(".resultSection").find(".pagination select").val($(this).val());
		         getClickHandler(parseInt($(this).val()))(evt);
		         return false;
		       });
		    
		    // Update the page count
		    panel.find(".pageCount").text(np);

			// Generate "Next"-Link
			if(opts.next_text && (current_page < np-1 || opts.next_show_always)){
				updateItem(current_page+1,{text:opts.next_text, act:"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();
	});
}