﻿$.fn.infiniteCarousel = function () {

	function repeat(str, num) {        
		return new Array( num + 1 ).join( str );
	}
	
	return this.each(function () {
		var $wrapper = $('> div', this).css('overflow', 'hidden'),
			$slider = $wrapper.find('> ul'),
			$items = $slider.find('> li'),
			$single = $items.filter(':first'),
			
			singleWidth = $single.outerWidth(),
			visible = Math.ceil($wrapper.innerWidth() / singleWidth), // note: doesn't include padding or border
			currentPage = 1,
			pages = Math.ceil($items.length / visible);

		// 1. Pad so that 'visible' number will always be seen, otherwise create empty items
		if (($items.length % visible) != 0) {
			$slider.append(repeat('<li class="empty" />', visible - ($items.length % visible)));
			$items = $slider.find('> li');
		}
	        
		// 2. Top and tail the list with 'visible' number of items, top has the last section, and tail has the first
		$items.filter(':first').before($items.slice(- visible).clone().addClass('cloned'));
		$items.filter(':last').after($items.slice(0, visible).clone().addClass('cloned'));
		$items = $slider.find('> li'); // reselect

		// 3. Set the left position to the first 'real' item
		$wrapper.scrollLeft(singleWidth * visible);

		// 4. paging function
		function gotoPage(page) {
			var dir = page < currentPage ? -1 : 1,
			n = Math.abs(currentPage - page),
			left = singleWidth * dir * visible * n;
	
			$wrapper.filter(':not(:animated)').animate({
				scrollLeft : '+=' + left            
			}, 500, function () {
				if (page == 0) {
					$wrapper.scrollLeft(singleWidth * visible * pages);
					page = pages;
				} else if (page > pages) {
					$wrapper.scrollLeft(singleWidth * visible);
					// reset back to start position
					page = 1;
				}
				currentPage = page;
			});
			return false;
		}
	
		// 5. Bind to the forward and back buttons
		$('a.back', this).click(function () {
			return gotoPage(currentPage - 1);
		});
	
		$('a.forward', this).click(function () {
			return gotoPage(currentPage + 1);
		});                
	
		// create a public interface to move to a specific page
		$(this).bind('goto', function (event, page) {
			gotoPage(page);
		});    
	});  
};
$(document).ready(function () {
	$('.infiniteCarousel').infiniteCarousel();
});
