var $window, 
	$window_width, 
	$window_height, 
	$frame_width, 
	$frame_height, 
	$body, 
	paper, 
	$paper_pages, 
	$sprites;
	
var options = {
	maxWindowWidth: 1440, 
	maxWindowHeight: 960, 
	scrollSpeed: 20
}


$(document).ready(function() { 
	$window = $(window);
	$window.bind('resize', positionElements);
	$window.bind('mousewheel', mouse_wheel);
	$window.bind('scroll', scroll);
	$body = $('body');
	$paper_pages = $('.section');
	$sprites = $('.sprite');
	positionElements();
	
	
	$('#what_we_do_menu > li > a').click(function() {
		$('.text_content').hide();
		$("#"+$(this).attr('id')+"_content").show();
	});
});

function mouse_wheel(event, delta) {
	window.scrollBy(-delta*options.scrollSpeed, 0);
};

function scroll(e) {
	$paper_pages.each(function(i) {
		var $sprites = $(this).children('.sprite');
		$sprites.each(function() {
			if(in_view($(this)))
			{
				$self = $(this);
				$parent = $self.parent();
				if($self.is('#book')) console.log($parent.position().left);
				var xadd = $self.attr('data-x') ? parseInt($self.attr('data-x')): 0;
				var xpos = xadd - ($window.scrollLeft() / parseInt($self.attr('data-speed')));
				var ypos = $self.attr('data-y') ? $self.attr('data-y'): 0;
				var coords = xpos + 'px ' + ypos + 'px';
				$self.css('background-position', coords);
			}
		});
	});	
}

function in_view(element) {
	var leftOffset = element.offset().left;
	return ($window.scrollLeft() >= leftOffset || $window.scrollLeft() + $window_width <= leftOffset + $window.width());
}

function scrollTo (target) {
	target = $('#'+target);
	var delta = (target.offset().left - $window.scrollLeft());
	$('body').stop().animate({
		scrollLeft: "+="+(delta-100)
	}, Math.abs(delta));
}

function positionElements() {
	$window_width = $window.width();
	$window_height = $window.height()-16;
	$frame_width = 1000; //$window_width > options.maxWindowWidth ? options.maxWindowWidth: $window_width;
	$frame_height = $window_height > options.maxWindowHeight ? options.maxWindowHeight: $window_height;
	
	$paper_pages.each(function(i) {
		var $self = $(this);
		
		$self.offset({left: i*$frame_width, top: 0})
		$self.width($frame_width);
		$self.height($frame_height);
		
		var $sprites = $self.children('.sprite');
		$sprites.each(function() {
			$self = $(this);
			$parent = $self.parent();
			$self.width($self.attr('data-width') ? parseInt($self.attr('data-width')): $frame_width);
			$self.height($window_height);
			var xadd = $self.attr('data-x') ? parseInt($self.attr('data-x')): 0;
			var xpos = xadd - ($window.scrollLeft() / parseInt($self.attr('data-speed')));
			var ypos = $self.attr('data-y') ? $self.attr('data-y'): 0;
			var coords = xpos + 'px ' + ypos + 'px';
			$self.css('background-position', coords);
		});
	});
}