( function( $ ) {
    $(document).ready(function(){
        
        // Auto-sizing
        imgSize = $('#slider img:first').height();        
        $('#slider').height(imgSize);
        
        // Create the animation zoom then fadeOut
        function zoomFade(element){
            element.fadeOut(250);
        }
        
        //create animation for captions
        function captionMove(element) {
            element.transition({
                opacity: 1,
                left: '50%'
            });
        }
        
        // Determinate number of slides, if only one is counted, hide arrows
        nbSlides = $('#slider .slide').length;
        
        if (nbSlides <= 1) {
            $('.arrow-container').hide();
        }
        
        // n is the current slide number nth-child(n)
        n = 1;
        
        // Init : show only first slide
        $('.slide').not('.slide:nth-child(' + n +')').hide();
        $('.slide').not('.slide:nth-child(' + n +')').find('.slide-caption').css({
            left: '60%'
        });
        
        // On arrow click :
        $('.arrow-container').click(function(){
            
            // Define if click is on "previous" or "next"
            direction = $(this).attr('id').split('-')[2];
            
            // Define current, previous and next slide
            // Current
            currentSlide = $('.slide:nth-child(' + n +')');
            currentCaption = $('.slide:nth-child(' + n +')').find('.slide-caption');
            
            // Previous
            if (n === 1) {
                previousSlide = $('.slide:nth-child(' + nbSlides + ')');
                previousCaption = $('.slide:nth-child(' + nbSlides + ')').find('.slide-caption');
            } else {
                previousSlide = $('.slide:nth-child(' + (n-1) +')');
                previousCaption = $('.slide:nth-child(' + (n-1) +')').find('.slide-caption');
            }
            
            // Next
            if (n === nbSlides) {
                nextSlide = $('.slide:nth-child(1)');
                nextCaption = $('.slide:nth-child(1)').find('.slide-caption');
            } else {
                nextSlide = $('.slide:nth-child(' + (n+1) + ')');
                nextCaption = $('.slide:nth-child(' + (n+1) + ')').find('.slide-caption');
            }
            
            // Finally : ACTION !!!
            
            zoomFade(currentSlide);
            currentCaption.transition({
                left: '60%',
                opacity: 0
            });
            
            if (direction === 'right') {
                
                nextSlide.fadeIn();
                nextCaption.transition({
                    left: '50%',
                    opacity: 1
                });
                if (n === nbSlides) {
                    n = 1;
                } else {
                    n = n+1;                
                }
                
            } else {
                
                previousSlide.fadeIn();
                previousCaption.transition({
                    left: '50%',
                    opacity: 1
                });
                
                if (n === 1) {
                    n = nbSlides;
                } else {
                    n = n-1;                
                }
                
            }
            
        });
        
    });
} )( jQuery );