;
(function($, window, document, undefined) {
	'use strict';

	function Paging(element, options) {
		this.element = element;
		this.options = {
			nowPage: options.nowPage || 1, // 当前页码
			pageNum: options.pageNum, // 总页码
			buttonNum: (options.buttonNum >= 5 ? options.buttonNum : 5) || 7, // 页面显示页码数量
			callback: options.callback // 回调函数
		};
		this.init();
	}
	Paging.prototype = {
		constructor: Paging,
		init: function() {
			this.createHtml();
			this.bindClickEvent();
			this.disabled();
		},
		createHtml: function() {
			var me = this;
			var nowPage = this.options.nowPage;
			var pageNum = this.options.pageNum;
			var buttonNum = this.options.buttonNum;
			var content = [];
			content.push("<ul>");
			content.push("<li class='xl-prevPage'>上一页</li>");
			//页面总数小于等于当前要展示页数总数，展示所有页面
			if (pageNum <= buttonNum) {
				for (var i = 1; i <= pageNum; i++) {
					if (nowPage !== i) {
						content.push("<li>" + i + "</li>");
					} else {
						content.push("<li class='xl-active'>" + i + "</li>");
					}
				}
			} else if (nowPage <= Math.floor(buttonNum / 2)) {
				//当前页面小于等于展示页数总数的一半（向下取整），从1开始
				for (var i = 1; i <= buttonNum - 2; i++) {
					if (nowPage !== i) {
						content.push("<li>" + i + "</li>");
					} else {
						content.push("<li class='xl-active'>" + i + "</li>");
					}
				}
				content.push("<li class='xl-disabled'>...</li>");
				content.push("<li>" + pageNum + "</li>");
			} else if (pageNum - nowPage <= Math.floor(buttonNum / 2)) {
				//当前页面大于展示页数总数的一半（向下取整）
				content.push("<li>" + 1 + "</li>");
				content.push("<li class='xl-disabled'>...</li>");
				for (var i = pageNum - buttonNum + 3; i <= pageNum; i++) {
					if (nowPage !== i) {
						content.push("<li>" + i + "</li>");
					} else {
						content.push("<li class='xl-active'>" + i + "</li>");
					}
				}
			} else {
				//前半部分页码
				if (nowPage - Math.floor(buttonNum / 2) <= 0) {
					for (var i = 1; i <= Math.floor(buttonNum / 2); i++) {
						if (nowPage !== i) {
							content.push("<li>" + i + "</li>");
						} else {
							content.push("<li class='xl-active'>" + i + "</li>");
						}
					}
				} else {
					content.push("<li>" + 1 + "</li>");
					content.push("<li class='xl-disabled'>...</li>");
					for (var i = nowPage - Math.floor(buttonNum / 2) + (buttonNum % 2 == 0 ? 3 : 2); i <=
						nowPage; i++) {
						if (nowPage !== i) {
							content.push("<li>" + i + "</li>");
						} else {
							content.push("<li class='xl-active'>" + i + "</li>");
						}
					}

				}
				//后半部分页码
				if (pageNum - nowPage <= 0) {
					for (var i = nowPage + 1; i <= pageNum; i++) {
						content.push("<li>" + i + "</li>");
					}
				} else {
					for (var i = nowPage + 1; i <= nowPage + Math.floor(buttonNum / 2) - 2; i++) {
						content.push("<li>" + i + "</li>");
					}
					content.push("<li class='xl-disabled'>...</li>");
					content.push("<li>" + pageNum + "</li>");
				}
			}
			content.push("<li class='xl-nextPage'>下一页</li>");
			content.push("</ul>");
			me.element.html(content.join(''));
			// DOM重新生成后每次调用是否禁用button
			setTimeout(function() {
				me.disabled();
			}, 20);

		},
		bindClickEvent: function() {
			var me = this;
			me.element.off('click', 'li');
			me.element.on('click', 'li', function() {
				var cla = $(this).attr('class');
				var num = parseInt($(this).html());
				var nowPage = me.options.nowPage;
				if ($(this).hasClass('xl-disabled')) {
					return;
				}
				if (cla === 'xl-prevPage') {
					if (nowPage !== 1) {
						me.options.nowPage -= 1;
					}
				} else if (cla === 'xl-nextPage') {
					if (nowPage !== me.options.pageNum) {
						me.options.nowPage += 1;
					}
				} else {
					me.options.nowPage = num;
				}
				me.createHtml();
				if (me.options.callback) {
					me.options.callback(me.options.nowPage);
				}
			});

		},
		disabled: function() {
			var me = this;
			var nowPage = me.options.nowPage;
			var pageNum = me.options.pageNum;
			if (nowPage === 1) {
				me.element.children().children('.xl-prevPage').addClass('xl-disabled');
			} else if (nowPage === pageNum) {
				me.element.children().children('.xl-nextPage').addClass('xl-disabled');
			}
		}
	}
	$.fn.paging = function(options) {
		return new Paging($(this), options);
	}
})(jQuery, window, document);