(function($){

	if (typeof window.CustomEvent !== "function") {
		function CustomEvent( event, params ) {
			params = params || { bubbles: false, cancelable: false, detail: undefined };
			var evt = document.createEvent( 'CustomEvent' );
			evt.initCustomEvent( event, params.bubbles, params.cancelable, params.detail );
			return evt;
		}
		CustomEvent.prototype = window.Event.prototype;
		window.CustomEvent = CustomEvent;
	}

	$.pageScroller = {

		items: $('.scroller-block'),
		navigationPane: null,
		activeItem: 0,
		animated: false,
		nextUpdate: false,

		init: function() {
			var that = this;
			$('body').css({overflow: 'hidden'});
			$(window).trigger('resize');
			if(that.items.length) {
				that.navigationPane = $('<div class="page-scroller-nav-pane"></div>');
				that.navigationPane.appendTo($('body'));
				that.items.each(function(index) {
					var $target = $(this);
					$('<a href="javascript:void(0);" class="page-scroller-nav-item"></a>')
						.appendTo(that.navigationPane)
						.data('scroller-target', $target)
						.on('click', function(e) {
							e.preventDefault();
							that.goTo(index);
						});
				});
			}
			setTimeout(function() {
				$('#page').scrollTop(0);
				that.update();
			}, 1);
			$(window).on('resize', function() {
				that.update();
			});
		},

		update: function() {
			var that = this;
			if(that.animated) {
				that.nextUpdate = true;
				return ;
			}
			that.animated = false;
			that.nextUpdate = false;
			if($.pageScroller.navigationPane.is(':visible')) {
				$('html, body').scrollTop(0);
			}
			$('#main').addClass('page-scroller-no-animate');
			$('#main').css('transform','translate3d(0,0,0)');
			that.items.each(function() {
				$(this).data('scroll-position', $(this).offset().top);
			});
			that.goTo(that.activeItem, function() {
				setTimeout(function() {
					$('#main').removeClass('page-scroller-no-animate');
				}, 100);
			});
		},

		next: function() {
			this.goTo(this.activeItem + 1);
		},

		prev: function() {
			this.goTo(this.activeItem - 1);
		},

		goTo: function(num, callback) {
			var that = this;
			if(that.animated) return;
			if(num == -1 || num >= this.items.length) return;
			var target_top = this.items.eq(num).data('scroll-position');
			var css = $('#main').css('transform');
			$('#main').css({'transform':'translate3d(0,-'+target_top+'px,0)'});
			setTimeout(function() {
				if(css == $('#main').css('transform')) {
					that.animated = false;
					that.activeItem = num;
					$('.page-scroller-nav-item', that.navigationPane).eq(num).addClass('active');
					if($.isFunction(callback)) callback();
					that.updateTrigger(that.items.eq(num));
					$('#main').off('webkitTransitionEnd otransitionend oTransitionEnd msTransitionEnd transitionend');
				}
			}, 50);
			$('.page-scroller-nav-item.active', that.navigationPane).removeClass('active');
			that.animated = true;
			if($('#main').hasClass('page-scroller-no-animate')) {
				that.animated = false;
				that.activeItem = num;
				$('.page-scroller-nav-item', that.navigationPane).removeClass('active').eq(num).addClass('active');
				if($.isFunction(callback)) callback();
				that.updateTrigger(that.items.eq(num));
			} else {
				$('#main').one('webkitTransitionEnd otransitionend oTransitionEnd msTransitionEnd transitionend', function(e) {
					that.animated = false;
					that.activeItem = num;
					$('.page-scroller-nav-item', that.navigationPane).removeClass('active').eq(num).addClass('active');
					if($.isFunction(callback)) callback();
					that.updateTrigger(that.items.eq(num));
					if(that.nextUpdate) {
						that.update();
					}
				});
			}

			that.items.removeClass('scroller-block-active').eq(num).addClass('scroller-block-active');
		},

		updateTrigger: function(elem) {
			$(document).trigger('update-page-scroller', elem);
			document.dispatchEvent(new window.CustomEvent('page-scroller-updated'));
		}

	};

	$(function() {
		if(!$('body').hasClass('compose-mode')) {
			$.pageScroller.init();
			var indicator = new WheelIndicator({
				elem: document.querySelector('body'),
				callback: function(e){
					if(e.direction == 'up') {
						$.pageScroller.prev();
					} else {
						$.pageScroller.next();
					}
				}
			});
			$(window).on('resize', function() {
				if($.pageScroller.navigationPane.is(':visible')) {
					indicator.turnOn();
				} else {
					indicator.turnOff();
				}
			});
			$('body').swipe({
				allowPageScroll:'vertical',
				preventDefaultEvents: false,
				swipe:function(event, direction, distance, duration, fingerCount) {
					if($.pageScroller.navigationPane.is(':visible')) {
						if(direction == 'down') {
							$.pageScroller.prev();
						}
						if(direction == 'up') {
							$.pageScroller.next();
						}
					}
				},
			});
		}
	});

})(jQuery);