/*
JavaScript for the demo: Recreating the Nikebetterworld.com Parallax Demo
Demo: Recreating the Nikebetterworld.com Parallax Demo
Author: Ian Lunn
Author URL: http://www.ianlunn.co.uk/
Demo URL: http://www.ianlunn.co.uk/demos/recreate-nikebetterworld-parallax/
Tutorial URL: http://www.ianlunn.co.uk/blog/code-tutorials/recreate-nikebetterworld-parallax/

License: http://creativecommons.org/licenses/by-sa/3.0/ (Attribution Share Alike). Please attribute work to Ian Lunn simply by leaving these comments in the source code or if you'd prefer, place a link on your website to http://www.ianlunn.co.uk/.

Dual licensed under the MIT and GPL licenses:
http://www.opensource.org/licenses/mit-license.php
http://www.gnu.org/licenses/gpl.html
*/

$(document).ready(function() { //when the document is ready...


	//save selectors as variables to increase performance
	var $window = $(window);
	var $firstBG = $('#intro');
	var $secondBG = $('#siste');
	var $thirdBG = $('#arbeid');
	var $fourthBG = $('#kontakt');
	var me = $("#me-pic");
	var info = $("#me-info");
	var latest = $("#siste #latest-work");
	
	var windowHeight = $window.height(); //get the height of the window
	
	
	//apply the class "inview" to a section that is in the viewport
	$('#intro, #siste, #arbeid, #kontakt, #fourth, .more').bind('inview', function (event, visible) {
			if (visible == true) {
			$(this).addClass("inview");
			} else {
			$(this).removeClass("inview");
			}
		});
	
			
	//function that places the navigation in the center of the window
	function RepositionNav(){
		var windowHeight = $window.height(); //get the height of the window
		var navHeight = $('#nav').height() / 2;
		var windowCenter = (windowHeight / 2); 
		var newtop = windowCenter - navHeight;
		$('#nav').css({"top": newtop}); //set the new top position of the navigation list
	}
	
	//function that is called for every pixel the user scrolls. Determines the position of the background
	/*arguments: 
		x = horizontal position of background
		windowHeight = height of the viewport
		pos = position of the scrollbar
		adjuster = adjust the position of the background
		inertia = how fast the background moves in relation to scrolling
	*/
	function newPos(x, windowHeight, pos, adjuster, inertia){
		return x + "% " + (-((windowHeight + pos) - adjuster) * inertia)  + "px";
	}
	
	function newPos2(x, windowHeight, pos, adjuster, inertia){
		return (-( (windowHeight + pos) - adjuster) * inertia)  + "px";
	}
	
	//function to be called whenever the window is scrolled or resized
	function Move(){ 
		var pos = $window.scrollTop(); //position of the scrollbar

		//if the first section is in view...
		if($firstBG.hasClass("inview")){
			//call the newPos function and change the background position
			$firstBG.css({'backgroundPosition': newPos(50, windowHeight, pos, 750, 0.3)});
			me.css({'backgroundPosition': newPos(31, windowHeight, pos, 800, 0.3)});		
		}
		
		//if the second section is in view...
		if($secondBG.hasClass("inview")){
			//call the newPos function and change the background position
			$secondBG.css({'backgroundPosition': newPos(50, windowHeight, pos, 1000, 0.4)});
			//call the newPos function and change the secnond background position
			latest.css({'left': '0', 'top': newPos2(50, windowHeight, pos, 1870, 0.3)});
			
		}

		if ( pos == 0 ) {
			$('#latest_sign').show();
		
		} else {
			$('#latest_sign').hide();	
		}
		
		if ( pos > 970 && pos < 1190 ) {
			$('#projects_sign').show();
		
		} else {
			$('#projects_sign').hide();	
		}
		
		if ( pos > 1950 && pos < 2290 ) {
			$('#contact_sign').show();
		
		} else {
			$('#contact_sign').hide();	
		}
		
		//if the second section is in view...
		if($(".more").hasClass("inview")){
			$('.pimage').each(function(index) {
				//var pimage = $('.pimage');
				var thumbOver = $(this).find("img").attr("src"); //Get image url and assign it to 'thumbOver'
				
				//Set a background image(thumbOver) on the &lt;a&gt; tag 
				$(this).find("span.preview").css({'background' : 'url(' + thumbOver + ') no-repeat center bottom'});
				//Fade the image to 0 
				$(this).find("img").stop().fadeTo('normal', 0 , function() {
					$(this).hide() //Hide the image after fade
				});
			});
			
			
		} else {
			$('.pimage').each(function(index) {
				$(this).find("img").stop().fadeTo('normal', 1).show();
			});
		}
		
		//if the third section is in view...
		if($thirdBG.hasClass("inview")){
			//call the newPos function and change the background position
			//$thirdBG.css({'backgroundPosition': newPos(50, windowHeight, pos, 2850, 0.3)});
		}
		
		//if the fourth section is in view...
		if($fourthBG.hasClass("inview")){
			//call the newPos function and change the background position for CSS3 multiple backgrounds
			//$fourthBG.css({'backgroundPosition': newPos(0, windowHeight, pos, 200, 0.9) + ", " + newPos(50, windowHeight, pos, 0, 0.7) + ", " + newPos(50, windowHeight, pos, 0, 0.5) + ", " + newPos(50, windowHeight, pos, 700, 0.3)});
		}
		
		//$('#pixels').html(pos); //display the number of pixels scrolled at the bottom of the page
	}
		
	RepositionNav(); //Reposition the Navigation to center it in the window when the script loads
	
	$window.resize(function(){ //if the user resizes the window...
		Move(); //move the background images in relation to the movement of the scrollbar
		RepositionNav(); //reposition the navigation list so it remains vertically central
	});		
	
	$window.bind('scroll', function(){ //when the user is scrolling...
		Move(); //move the background images in relation to the movement of the scrollbar
	});
	
});