var cur_back = -1;
var num_backs = 0;
var fade_speed = 2000;
var fade_time = 5000;
var next_back = 0;

jQuery(window).load(function(){
	//get the number of backgrounds
	num_backs = jQuery(".background-image").length;
	
	//set the original width
	jQuery(".background-image").each(function(){
		jQuery(this).data({ 'width':jQuery(this).width() });
	});
	
	//window resize function
	jQuery(window).resize(function() {
		resizeBg(cur_back);
		resizeBg(next_back);
	});
	
	//start slideshow
	runSlideShow(1);
});

function resizeBg(index) {
	var bg = jQuery(".background-image").eq(index);
	
	if(bg.data('width') < jQuery(window).width()){
		var left = (jQuery(window).width() / 2) - (bg.data('width') / 2);
		bg.css({ 'left':left, 'width':bg.data('width') });
	} else if(jQuery(window).width() < jQuery(".wrapper").width()){
		bg.css({ 'left':0, 'width':jQuery('.wrapper').width() });
	} else {
		bg.css({ 'width':'100%', 'left':0 });
	}
}

function runSlideShow(dir){
	//get next image
	if(dir+cur_back >= num_backs){
		next_back = 0;
	} else {
		next_back = cur_back+dir;
	}
	
	//resize the current
	resizeBg(cur_back);
	resizeBg(next_back);

	//animate in next image
	jQuery('.background-image').eq(next_back).fadeIn(fade_speed,function(){
		cur_back = next_back;
		setTimeout(function(){ runSlideShow(dir); },fade_time);
	});
	
	//animate out last image
	jQuery('.background-image').eq(cur_back).fadeOut(fade_speed);
}