;(function( $ ){

	var $serialScroll = $.serialScroll = function( settings ){
		$.scrollTo.window().serialScroll( settings );
	};

	$serialScroll.defaults = {
		duration:1000,
		axis:'x',
		event:'click', 
		start:0,
		step:1, 
		lock:true,
		cycle:true,
		constant:true 
	};

	$.fn.serialScroll = function( settings ){
		settings = $.extend( {}, $serialScroll.defaults, settings );
		var event = settings.event, 
			step = settings.step, 
			lazy = settings.lazy;

		return this.each(function(){
			var 
				context = settings.target ? this : document,
				$pane = $(settings.target || this, context),
				pane = $pane[0],
				items = settings.items,
				active = settings.start, 
				auto = settings.interval, 
				nav = settings.navigation, 
				timer; 

			if( !lazy )
				items = getItems();

			if( settings.force )
				jump( {}, active );

			
			$(settings.prev||[], context).bind( event, -step, move );
			$(settings.next||[], context).bind( event, step, move );

			
			if( !pane.ssbound )
				$pane
					.bind('prev.serialScroll', -step, move ) 
					.bind('next.serialScroll', step, move )
					.bind('goto.serialScroll', jump );
			if( auto )
				$pane
					.bind('start.serialScroll', function(e){
						if( !auto ){
							clear();
							auto = true;
							next();
						}
					 })
					.bind('stop.serialScroll', function(){
						clear();
						auto = false;
					});
			$pane.bind('notify.serialScroll', function(e, elem){
				var i = index(elem);
				if( i > -1 )
					active = i;
			});
			pane.ssbound = true;

			if( settings.jump )
				(lazy ? $pane : getItems()).bind( event, function( e ){
					jump( e, index(e.target) );
				});

			if( nav )
				nav = $(nav, context).bind(event, function( e ){
					e.data = Math.round(getItems().length / nav.length) * nav.index(this);
					jump( e, this );
				});

			function move( e ){
				e.data += active;
				jump( e, this );
			};
			function jump( e, button ){
				if( !isNaN(button) ){
					e.data = button;
					button = pane;
				}

				var
					pos = e.data, n,
					real = e.type,
					$items = settings.exclude ? getItems().slice(0,-settings.exclude) : getItems(),
					limit = $items.length,
					elem = $items[pos],
					duration = settings.duration;

				if( real )
					e.preventDefault();

				if( auto ){
					clear();
					timer = setTimeout( next, settings.interval ); 
				}

				if( !elem ){ 
					n = pos < 0 ? 0 : limit - 1;
					if( active != n )
						pos = n;
					else if( !settings.cycle )
						return;
					else
						pos = limit - n - 1
					elem = $items[pos];
				}

				if( !elem || real && active == pos ||
					settings.lock && $pane.is(':animated') ||
					real && settings.onBefore &&
					settings.onBefore.call(button, e, elem, $pane, getItems(), pos) === false ) return;

				if( settings.stop )
					$pane.queue('fx',[]).stop();

				if( settings.constant )
					duration = Math.abs(duration/step * (active - pos ));

				$pane
					.scrollTo( elem, duration, settings )
					.trigger('notify.serialScroll',[pos]);
			};
			function next(){
				$pane.trigger('next.serialScroll');
			};
			function clear(){
				clearTimeout(timer);
			};
			function getItems(){
				return $( items, pane );
			};
			function index( elem ){
				if( !isNaN(elem) ) return elem;
				var $items = getItems(), i;
				while(( i = $items.index(elem)) == -1 && elem != pane )
					elem = elem.parentNode;
				return i;
			};
		});
	};

})( jQuery );