/**
 * @author Stéphane Roucheray 
 * @extends jquery
 */

jQuery.fn.carousel = function(previous, next, options){
	var sliderList = jQuery(this).children()[0];
	
	if (sliderList) {
                var intervalId= null;
                var animTime= options!=null && options.animTime ? options.animTime : 666;
                var easing= options!=null && options.easing ? options.easing : "swing";
		var increment = jQuery(sliderList).children().outerWidth("true"),
		elmnts = jQuery(sliderList).children(),
		numElmts = elmnts.length,
		sizeFirstElmnt = increment,
		shownInViewport = Math.round(jQuery(this).width() / sizeFirstElmnt),
		firstElementOnViewPort = 1,
		isAnimating = false;
		
		for (i = 0; i < shownInViewport; i++) {
			jQuery(sliderList).css('width',(numElmts+shownInViewport)*increment + increment + "px");
			jQuery(sliderList).append(jQuery(elmnts[i]).clone());
		}
		
		jQuery(previous).click(function(event){
			if (!isAnimating) {
				if (firstElementOnViewPort == 1) {
					jQuery(sliderList).css('left', "-" + numElmts * sizeFirstElmnt + "px");
					firstElementOnViewPort = numElmts;
				}
				else {
					firstElementOnViewPort--;
				}
				
                                restartInterval();
				jQuery(sliderList).animate({
					left: "+=" + increment,
					y: 0,
					queue: true
				}, animTime,  easing, function(){isAnimating = false;});
				isAnimating = true;
			}
			
		});
		
		jQuery(next).click(function(event){
			if (!isAnimating) {
				if (firstElementOnViewPort > numElmts) {
					firstElementOnViewPort = 2;
					jQuery(sliderList).css('left', "0px");
				}
				else {
					firstElementOnViewPort++;
				}
                                restartInterval();
				jQuery(sliderList).animate({
					left: "-=" + increment,
					y: 0,
					queue: true
				}, animTime, easing, function(){isAnimating = false;});
				isAnimating = true;
			}
		});

                function restartInterval() {
                    clearTimeout(intervalId);
                    intervalId= window.setInterval(function() {$(next).click(); }, options.interval);
                } 

                if (options.interval)
                    restartInterval();
                                   
	}
};