// Easing equation, borrowed from jQuery easing plugin
// http://gsgd.co.uk/sandbox/jquery/easing/

jQuery.easing.easeOutQuart = function (x, t, b, c, d) {
	return -c * ((t=t/d-1)*t*t*t - 1) + b;
};

// Serial scroll

jQuery(function( $ ){	
	$('.tumblr-content-container').serialScroll({
		items:'.post',
		prev:'.section-content-wide .prev a',
		next:'.section-content-wide .next a',
		offset:-100, //when scrolling to photo, stop -100 before reaching it (from the left)
		start:0, //first item
		duration:1200,
		force:true,
		stop:true,
		lock:false,
		cycle:false, 
		easing:'easeOutQuart',
		jump: false //click on the images to scroll to them
	});
});

// Background scrolling

function init_scrolling() {
	// Set css-properties for scrolling
	// #header
	headerPosBg = -100;
	$("div#header div.section-bg div.background").css("background-position", "center " + headerPosBg + "px");
	
	// #band
	bandPosBg = 0;
	bandPosBglayer1 = 2000;
	bandPosBglayer2 = 1200;
	$("div#band div.section-bg div.background").css("background-position", "center " + bandPosBg + "px");
	$("div#band div.section-bg div.layer1").css("background-position", "center " + bandPosBglayer1 + "px");
	$("div#band div.section-bg div.layer2").css("background-position", "center " + bandPosBglayer2 + "px");
	
	// #disco
	discoPosBg = 2300;
	$("div#disco div.section-bg div.background").css("background-position", "center " + discoPosBg + "px");
	
	// Do the actual scrolling
	$(window).scroll(function(){
		var x = $(this).scrollTop();
		if (x > 0) {
			newheaderPosBg = headerPosBg - (5*x);
			$("div#header div.section-bg div.background").css("background-position", "center " + newheaderPosBg + "px");
			
			newbandPosBg = bandPosBg - (x/3);
			newbandPosBglayer1 = bandPosBglayer1 - (4*x);
			newbandPosBglayer2 = bandPosBglayer2 - (1.5*x);
			$("div#band div.section-bg div.background").css("background-position", "center " + newbandPosBg + "px");
			$("div#band div.section-bg div.layer1").css("background-position", "center " + newbandPosBglayer1 + "px");
			$("div#band div.section-bg div.layer2").css("background-position", "center " + newbandPosBglayer2 + "px");
			
			newdiscoPosBg = discoPosBg - (x/2);
			$("div#disco div.section-bg div.background").css("background-position", "center " + newdiscoPosBg + "px");
		}
		
		else {
			$("div#header div.section-bg div.background").css("background-position", "center " + headerPosBg + "px");
			$("div#disco div.section-bg div.background").css("background-position", "center " + discoPosBg + "px");
			$("div#band div.section-bg div.background").css("background-position", "center " + bandPosBg + "px");
			$("div#band div.section-bg div.layer1").css("background-position", "center " + bandPosBglayer1 + "px");
			$("div#band div.section-bg div.layer2").css("background-position", "center " + bandPosBglayer2 + "px");
		}
	});
}

function checkScrolling () {
	retVal = 0; //alert('Browserinfo: ' + $.browser.name + ' - ' + $.browser.versionNumber + ' - ' + $.os.name);
	
	// Enable on Firefox from version 3 on all OS types
	if ($.browser.name == 'firefox' && $.browser.versionNumber >= 3) {
		retVal = 1;
	}
	// Enable on Chrome from version 7 on all OS types
	if ($.browser.name == 'chrome' && $.browser.versionNumber >= 7) {
		retVal = 1;
	}
	// Enable on Safari from version 4
	if ($.browser.name == 'safari' && $.browser.versionNumber >= 4 && ($.os.name == 'mac' || $.os.name == 'win')) {
		retVal = 1;
	}
	// Enable on Opera from version 9 on all OS types
	if ($.browser.name == 'opera' && $.browser.versionNumber >= 9) {
		retVal = 1;
	}
	// Enable on IE versions above 6
	if ($.browser.name == 'msie' && $.browser.versionNumber > 6) {
		retVal = 1;
	}
	return retVal;
}

$(document).ready ( function () {
	if ($.browser.name == 'msie' && $.browser.versionNumber < 8) {
		$("div#goudeneeuw div.section-bg div.section-bg-extra").css("background-image","none");
	}
	doScrolling = 0;
	doScrolling = checkScrolling();
	if (doScrolling == 1) {
		init_scrolling();
	}
});