// Animate the atlas screen images by calling puff on them

var ScreenSlides = {
	delay : 5000, 
	
	// Get hold of our slides, and set up a timer to animate
	init : function () {
		ScreenSlides.slides = $A(document.getElementsByClassName('screen_slide'));
		ScreenSlides.current = 1;
		// Just to be safe show first
		ScreenSlides.current_slide().show();
		setInterval("ScreenSlides.animate();",ScreenSlides.delay);
	},
	
	// Hide all our slides
	hide_all_slides: function(){
		ScreenSlides.slides.each(function(slide){
			new Effect.Fade(slide);
		});

	},

	// Show one slide (the next one)
	current_slide: function() {
		return ScreenSlides.slides[ScreenSlides.current -1];
	},

	// Show one slide (the next one)
	show_next_slide: function() {
		var curr_slide = ScreenSlides.current_slide();
		ScreenSlides.increment_counter();
		var next_slide = ScreenSlides.current_slide();
		if (curr_slide)
			{
			curr_slide.style.zIndex = "3";	
			next_slide.style.zIndex = "1";
			next_slide.show();
			new Effect.Fade(curr_slide, {duration:1.0});
			}
	},

	// Increment our counter (with overflow)
	increment_counter: function() {
		ScreenSlides.current = ScreenSlides.current + 1;
		if (ScreenSlides.current > ScreenSlides.slides.length) {ScreenSlides.current = 1};
	},
	
	// called on a timer - animates our home page images
	animate: function(){
		// Show the next slide
		ScreenSlides.show_next_slide();
	}
	
};


Event.observe(window,'load',ScreenSlides.init,false);