jQuery.fn.slider = function(settings) {
	settings = jQuery.extend({
		speed: "normal",
		slideBy: 3,
		pagerId: "pager",
		nextId: "next",
		previousId: "previous",
		continuous: true,
		autoPlay: false,
		timeout: 10000
	}, settings);
	return this.each(function() {
		jQuery.fn.slider.run(jQuery(this), settings);
	});
};

jQuery.fn.slider.run = function($this, settings) {
	var currentPage = 0;
	var ul = jQuery("ul:eq(0)", $this);
	var li = ul.children();
	if (li.length > settings.slideBy) {
		var $next = jQuery("#" + settings.nextId, $this);
		var $back = jQuery("#" + settings.previousId, $this);
		if (settings.continuous == false) $back.fadeTo("fast", 0.4);

		var liWidth = jQuery(li[0]).outerWidth(true);
		var length = li.length;
		var extraItems = length % settings.slideBy;
		for (var i = 0; i < extraItems; i++) {
			ul.append("<li></li>");
			length++;
		}
		var pageCount = length / settings.slideBy;
		for (var i = 0; i < pageCount; i++) {
			$(document.createElement("a"))
				.attr('id', settings.pagerId + "_" + i)
				.attr('rel', i)
				.attr('href', "javascript:void(0);")
				.appendTo($("#" + settings.pagerId))
				.html("&nbsp;")
				.click(function() {
					animate($(this).attr('rel'));
				});
		};
		if (settings.continuous) {
			ul.append(jQuery("ul li", $this).slice(0, parseInt(settings.slideBy)).clone());
			length = ul.children().length;
		};
		ul.css("width", (length * liWidth));
		var animating = false;
		$next.click(function() {
			clearInterval(_timer);
			next();
			return false;
		});
		$back.click(function() {
			clearInterval(_timer);
			previous();
			return false;
		});
		function next() {
			var pageNumber = parseInt(currentPage) + 1;
			if (pageNumber == pageCount && settings.continuous == false) { }
			else animate(pageNumber);
		}
		function previous() {
			var pageNumber = parseInt(currentPage) - 1;
			if (currentPage == 0 && settings.continuous == false) { }
			else animate(pageNumber);
		}
		function animate(pageNumber) {
			setCurrent(pageNumber);
			var slideLength = 0;
			if (pageNumber < 0 && settings.continuous) {
				ul.css("left", (liWidth * settings.slideBy) * pageCount * -1);
				slideLength = liWidth * (length - settings.slideBy * 2) * -1;
			}
			else {
				slideLength = (liWidth * settings.slideBy) * pageNumber * -1;
			}
			ul.animate({
				left: slideLength
			}, settings.speed, function() {
				if (currentPage == (pageCount - 1) && settings.continuous == false) {
					$next.fadeTo("fast", 0.4);
					$back.fadeTo("fast", 1);
					return;
				}
				else if (currentPage == 0 && settings.continuous == false) {
					$back.fadeTo("fast", 0.4);
					$next.fadeTo("fast", 1);
					return;
				}
				if (pageNumber == pageCount)
					ul.css("left", 0);
			});
		}
		function setCurrent(i) {
			$("#" + settings.pagerId + "_" + currentPage).removeClass("current");
			if (i < 0) currentPage = (pageCount - 1);
			else currentPage = i < pageCount ? i : 0;
			$("#" + settings.pagerId + "_" + currentPage).addClass("current");
		};
		//init
		setCurrent(0);

		var _timer;
		if (settings.autoPlay) {
			_timer = setInterval(function() {
				next();
			}, settings.timeout);
		};
	}
}