$(document).ready(function(){
    var currentPosition = 0;
    var slideWidth = 870;
    var slides = $('.slide');
    var numberOfSlides = slides.length;

    // Remove scrollbar in JS
    $('#slidesContainer').css('overflow', 'hidden');

    // Wrap all .slides with #slideInner div
    slides
    .wrapAll('<div id="slideInner"></div>')
    // Float left to display horizontally, readjust .slides width
    .css({
    'float' : 'left',
    'width' : slideWidth
    });

    // Set #slideInner width equal to total width of all slides
    $('#slideInner').css('width', slideWidth * numberOfSlides);

    // Insert left and right arrow controls in the DOM
    $('#slideshow')
    .prepend('<span class="control" id="leftControl">Move left</span>')
    .append('<span class="control" id="rightControl">Move right</span>');

    // Hide left arrow control on first load
    manageControls(currentPosition);

    // Create event listeners for .controls clicks
    $('.control')
    .bind('click', function(){
        // Determine new position
        currentPosition = ($(this).attr('id')=='rightControl') ? currentPosition+1 : currentPosition-1;
        
        // Hide / show controls
        manageControls(currentPosition);
        
        // Move slideInner using margin-left
        $('#slideInner').animate({
            'marginLeft' : slideWidth*(-currentPosition)
        });
    });

    // manageControls: Hides and shows controls depending on currentPosition
    function manageControls(position){
        // Hide left arrow if position is first slide
        if (position==0) {
            $('#leftControl').hide();
        } else {
            $('#leftControl').show();
        }
        
        // Hide right arrow if position is last slide
        if (position==numberOfSlides-1) {
            $('#rightControl').hide();
        } else {
            $('#rightControl').show();
        }
    }
});