//滚动数字
(function($) {

	$.fn.countTo = function (options) {
		options = options || {};
		
		return $(this).each(function () {
			// set options for current element
			var settings = $.extend({}, $.fn.countTo.defaults, {
				from:            $(this).data('from'),
				to:              $(this).data('to'),
				speed:           $(this).data('speed'),
				refreshInterval: $(this).data('refresh-interval'),
				decimals:        $(this).data('decimals')
			}, options);
			
			// how many times to update the value, and how much to increment the value on each update
			var loops = Math.ceil(settings.speed / settings.refreshInterval),
				increment = (settings.to - settings.from) / loops;
			
			// references & variables that will change with each update
			var self = this,
				$self = $(this),
				loopCount = 0,
				value = settings.from,
				data = $self.data('countTo') || {};
			
			$self.data('countTo', data);
			
			// if an existing interval can be found, clear it first
			if (data.interval) {
				clearInterval(data.interval);
			}
			data.interval = setInterval(updateTimer, settings.refreshInterval);
			
			// initialize the element with the starting value
			render(value);
			
			function updateTimer() {
				value += increment;
				loopCount++;
				
				render(value);
				
				if (typeof(settings.onUpdate) == 'function') {
					settings.onUpdate.call(self, value);
				}
				
				if (loopCount >= loops) {
					// remove the interval
					$self.removeData('countTo');
					clearInterval(data.interval);
					value = settings.to;
					
					if (typeof(settings.onComplete) == 'function') {
						settings.onComplete.call(self, value);
					}
				}
			}
			
			function render(value) {
				var formattedValue = settings.formatter.call(self, value, settings);
				$self.html(formattedValue);
			}
		});
	};
	
	$.fn.countTo.defaults = {
		from: 0,               // the number the element should start at
		to: 0,                 // the number the element should end at
		speed: 1000,           // how long it should take to count between the target numbers
		refreshInterval: 100,  // how often the element should be updated
		decimals: 0,           // the number of decimal places to show
		formatter: formatter,  // handler for formatting the value before rendering
		onUpdate: null,        // callback method for every time the element is updated
		onComplete: null       // callback method for when the element finishes updating
	};
	
	function formatter(value, settings) {
		return value.toFixed(settings.decimals);
	}

	// custom formatting example
	$('.count-number').each(function () {
		const $this = $(this);

		$this.data('countToOptions', {
			formatter: function (value, options) {
				// 判断是否有千位分割符 class 'comma'
				if ($this.hasClass('comma')) {
					return value.toFixed(options.decimals).replace(/\B(?=(\d{3})+(?!\d))/g, ',');
				} else {
					return value.toFixed(options.decimals);
				}
			}
		});
	});

	// start all the timers
	// 创建 Intersection Observer
	const observer = new IntersectionObserver(entries => {
		entries.forEach(entry => {
			if (entry.isIntersecting) {
				// 元素出现在可视区域
				$('.timer').each(count);
				// 停止监听
				observer.disconnect();
			}
		});
	});

	// 监听目标元素
	const ThemeCount = $('.module-theme-count');
	if (ThemeCount.length > 0) {
		observer.observe(document.querySelector('.module-theme-count'));
	}

	function count(options) {
		var $this = $(this);
		options = $.extend({}, options || {}, $this.data('countToOptions') || {});
		$this.countTo(options);
	}

})(jQuery);