$.fn.product_carousel = function (category) {

    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 = $single.outerWidth(), 
            visible = Math.floor($wrapper.innerWidth() / singleWidth), // note: doesn't include padding or border
            currentPage = 1,
            totalitems = $items.length,
            pages = Math.ceil(totalitems / 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
            }, 1000, 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;
        }
        if (totalitems > 4) { // only place navigation when needed
        	$wrapper.after('<div id="product_nav"><img id="product_prev" src="/gfx/'+category+'_arrow_prev.png" alt="back"/><img src="/gfx/'+category+'_arrow_divider.png" alt="" width="2"/><img id="product_next" src="/gfx/'+category+'_arrow_next.png" alt="next"/></div>');
        
	        // 5. Bind to the forward and back buttons
	        $('#product_prev', this).click(function () {
	            return gotoPage(currentPage - 1);                
	        });
	        
	        $('#product_next', 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);
	        });

        }
    });  
};