$(function(){
	
	var $page_menu = $('.sticky_menu');
	
	if ($page_menu.length) {
		$(window).on('load', function(){
			$page_menu.data('position', 'undefined');
			
			var MENU_OFFSET = 20,
				page_menu_height = $page_menu.height(),
				top_guide = $('header').height(),
				bottom_guide = $('body').height() - $('footer').height() - page_menu_height - (2 * MENU_OFFSET);
			
			function getScrollTop(){
				if (typeof pageYOffset != 'undefined') {
					//most browsers except IE before #9
					return pageYOffset;
				} else {
					var B = document.body; //IE 'quirks'
					var D = document.documentElement; //IE with doctype
					D = (D.clientHeight)? D: B;
					return D.scrollTop;
				}
			}
			
			function onScroll(){
				var scroll = getScrollTop();
				
				// TOP
				if (scroll < top_guide) {
					if ($page_menu.data('position') != 'top') {
						$page_menu.data('position', 'top');
						$page_menu.css({
							'position' : 'absolute',
							'top' : top_guide + MENU_OFFSET
						});
					}
				}
				
				// MIDDLE
				else if (scroll >= top_guide && scroll < bottom_guide) {
					if ($page_menu.data('position') != 'middle') {
						$page_menu.data('position', 'middle');
						$page_menu.css({
							'position' : 'fixed',
							'top' : MENU_OFFSET
						});
					}
				}
				
				// BOTTOM
				else {
					if ($page_menu.data('position') != 'bottom') {
						$page_menu.data('position', 'bottom');
						$page_menu.css({
							'position' : 'absolute',
							'top' : bottom_guide + MENU_OFFSET
						});
					}
				}
				
			};
			
			$page_menu.onePageNav({
				currentClass: 'active'
			});
			
			$(window).scroll(onScroll).trigger('scroll');
		});
	}
});