// JavaScript Document

$(document).ready(function(){
  var currentPosition = 0;
  var slideWidth = 970;
  var slides = $('.slide');
  var numberOfSlides = slides.length;
  var slideTimer;
  var autoDirection = "right";

  // 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(){
		
	// STOP TIMER
	clearTimeout(slideTimer);	
		
    // 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)
      });
	  
	  autoSlide();
	  
    });
	  

  // 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() }
    }



  // automated animation
   
   
	function autoSlide(){
		
		slideTimer = setTimeout(function() {
			
			if(currentPosition == 0){
				autoDirection="right";
			}else if(currentPosition == numberOfSlides-1){
				autoDirection="left";
			}
			
			if(autoDirection == "right"){
				$('#rightControl').click();
			}else{
				//$('#leftControl').click();
			    resetAutoSlide();
			}
			
		}, 6000);
		
	}
	
	autoSlide();
	
	function resetAutoSlide(){
		
	  currentPosition = 0;
	  
	  manageControls(currentPosition);
	  
	  $('#slideInner').animate({
		'marginLeft' : 0
	  });			
	  
	  autoSlide();
	  	
	}

});












// GREYSCALE


// On window load. This waits until images have loaded which is essential
	$(window).load(function(){
		
		// Fade in images so there isn't a color "pop" document load and then on window load
		$(".sponsor-item img").fadeIn(500);
		
		// clone image
		$('.sponsor-item img').each(function(){
			var el = $(this);
			el.css({"position":"absolute"}).wrap("<div class='img_wrapper' style='display: inline-block'>").clone().addClass('img_grayscale').css({"position":"absolute","z-index":"998","opacity":"0"}).insertBefore(el).queue(function(){
				var el = $(this);
				el.parent().css({"width":this.width,"height":this.height});
				el.dequeue();
			});
			this.src = grayscale(this.src);
		});
		
		// Fade image 
		$('.sponsor-item img').mouseover(function(){
			$(this).parent().find('img:first').stop().animate({opacity:1}, 200);
		})
		$('.img_grayscale').mouseout(function(){
			$(this).stop().animate({opacity:0}, 1000);
		});		
	});
	
	// Grayscale w canvas method
	function grayscale(src){
		var canvas = document.createElement('canvas');
		var ctx = canvas.getContext('2d');
		var imgObj = new Image();
		imgObj.src = src;
		canvas.width = imgObj.width;
		canvas.height = imgObj.height; 
		ctx.drawImage(imgObj, 0, 0); 
		var imgPixels = ctx.getImageData(0, 0, canvas.width, canvas.height);
		for(var y = 0; y < imgPixels.height; y++){
			for(var x = 0; x < imgPixels.width; x++){
				var i = (y * 4) * imgPixels.width + x * 4;
				var avg = (imgPixels.data[i] + imgPixels.data[i + 1] + imgPixels.data[i + 2]) / 3;
				imgPixels.data[i] = avg; 
				imgPixels.data[i + 1] = avg; 
				imgPixels.data[i + 2] = avg;
			}
		}
		ctx.putImageData(imgPixels, 0, 0, 0, 0, imgPixels.width, imgPixels.height);
		return canvas.toDataURL();
    }