/**
 * @author S. Roucheray 
 * @extends jquery
 */


jQuery.fn.carousel = function(previous, next, options){
  var sliderList = jQuery(this).children()[0];
  
  if (sliderList) {
    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--;
        }
        
        jQuery(sliderList).animate({
          left: "+=" + increment,
          y: 0,
          queue: true
        }, "swing", function(){isAnimating = false;});
        isAnimating = true;
      }
      
    });
    
    jQuery(next).click(function(event){
      if (!isAnimating) {
        if (firstElementOnViewPort > numElmts) {
          firstElementOnViewPort = 2;
          jQuery(sliderList).css('left', "0px");
        }
        else {
          firstElementOnViewPort++;
        }
        jQuery(sliderList).animate({
          left: "-=" + increment,
          y: 0,
          queue: true
        }, "swing", function(){isAnimating = false;});
        isAnimating = true;
      }
    });
  }
};