(function () {

    var doc = document
        , id = 'getElementById'
        , tag = 'getElementsByTagName'

        //字符常量
        , MOD_NAME = 'laypage', DISABLED = 'layui-disabled'

        //构造器
        , Class = function (options) {
            var that = this;
            that.config = options || {};
            that.config.index = ++laypage.index;
            that.render(true);
        };

    //判断传入的容器类型
    Class.prototype.type = function () {
        var config = this.config;
        if (typeof config.elem === 'object') {
            return config.elem.length === undefined ? 2 : 3;
        }
    };

    //分页视图
    Class.prototype.view = function () {
        var that = this
            , config = that.config
            , groups = config.groups = 'groups' in config ? (config.groups | 0) : 5; //连续页码个数

        //排版
        config.layout = typeof config.layout === 'object'
            ? config.layout
            : ['prev', 'page', 'next'];

        config.count = config.count | 0; //数据总数
        config.curr = (config.curr | 0) || 1; //当前页

        //每页条数的选择项
        config.limits = typeof config.limits === 'object'
            ? config.limits
            : [10, 20, 30, 40, 50];
        config.limit = (config.limit | 0) || 10; //默认条数

        //总页数
        config.pages = Math.ceil(config.count / config.limit) || 1;

        //当前页不能超过总页数
        if (config.curr > config.pages) {
            config.curr = config.pages;
        }

        //连续分页个数不能低于0且不能大于总页数
        if (groups < 0) {
            groups = 1;
        } else if (groups > config.pages) {
            groups = config.pages;
        }

        config.prev = 'prev' in config ? config.prev : '&#x4E0A;&#x4E00;&#x9875;'; //上一页文本
        config.next = 'next' in config ? config.next : '&#x4E0B;&#x4E00;&#x9875;'; //下一页文本

        //计算当前组
        var index = config.pages > groups
            ? Math.ceil((config.curr + (groups > 1 ? 1 : 0)) / (groups > 0 ? groups : 1))
            : 1

            //试图片段
            , views = {
                //上一页
                prev: function () {
                    return config.prev
                        ? '<a href="javascript:;" class="layui-laypage-prev' + (config.curr == 1 ? (' ' + DISABLED) : '') + '" data-page="' + (config.curr - 1) + '">' + config.prev + '</a>'
                        : '';
                }()

                //页码
                , page: function () {
                    var pager = [];

                    //数据量为0时，不输出页码
                    if (config.count < 1) {
                        return '';
                    }

                    //首页
                    if (index > 1 && config.first !== false && groups !== 0) {
                        pager.push('<a href="javascript:;" class="layui-laypage-first" data-page="1"  title="&#x9996;&#x9875;">' + (config.first || 1) + '</a>');
                    }

                    //计算当前页码组的起始页
                    var halve = Math.floor((groups - 1) / 2) //页码数等分
                        , start = index > 1 ? config.curr - halve : 1
                        , end = index > 1 ? (function () {
                        var max = config.curr + (groups - halve - 1);
                        return max > config.pages ? config.pages : max;
                    }()) : groups;

                    //防止最后一组出现“不规定”的连续页码数
                    if (end - start < groups - 1) {
                        start = end - groups + 1;
                    }

                    //输出左分割符
                    if (config.first !== false && start > 2) {
                        pager.push('<span class="layui-laypage-spr">&#x2026;</span>')
                    }

                    //输出连续页码
                    for (; start <= end; start++) {
                        if (start === config.curr) {
                            //当前页
                            pager.push('<span class="layui-laypage-curr"><em class="layui-laypage-em" ' + (/^#/.test(config.theme) ? 'style="background-color:' + config.theme + ';"' : '') + '></em><em>' + start + '</em></span>');
                        } else {
                            pager.push('<a href="javascript:;" data-page="' + start + '">' + start + '</a>');
                        }
                    }

                    //输出输出右分隔符 & 末页
                    if (config.pages > groups && config.pages > end && config.last !== false) {
                        if (end + 1 < config.pages) {
                            pager.push('<span class="layui-laypage-spr">&#x2026;</span>');
                        }
                        if (groups !== 0) {
                            pager.push('<a href="javascript:;" class="layui-laypage-last" title="&#x5C3E;&#x9875;"  data-page="' + config.pages + '">' + (config.last || config.pages) + '</a>');
                        }
                    }

                    return pager.join('');
                }()

                //下一页
                , next: function () {
                    return config.next
                        ? '<a href="javascript:;" class="layui-laypage-next' + (config.curr == config.pages ? (' ' + DISABLED) : '') + '" data-page="' + (config.curr + 1) + '">' + config.next + '</a>'
                        : '';
                }()

                //数据总数
                , count: '<span class="layui-laypage-count">共 ' + config.count + ' 条</span>'

                //每页条数
                , limit: function () {
                    var options = ['<span class="layui-laypage-limits"><select lay-ignore>'];
                    config.limits.forEach(function (item, index) {
                        options.push(
                            '<option value="' + item + '"'
                            + (item === config.limit ? 'selected' : '')
                            + '>' + item + ' 条/页</option>'
                        );
                    })
                    return options.join('') + '</select></span>';
                }()

                //跳页区域
                , skip: function () {
                    return ['<span class="layui-laypage-skip">&#x5230;&#x7B2C;'
                        , '<input type="text" min="1" value="' + config.curr + '" class="layui-input">'
                        , '&#x9875;<button type="button" class="layui-laypage-btn">&#x786e;&#x5b9a;</button>'
                        , '</span>'].join('');
                }()
            };

        return ['<div class="layui-box layui-laypage layui-laypage-' + (config.theme ? (
            /^#/.test(config.theme) ? 'molv' : config.theme
        ) : 'default') + '" id="layui-laypage-' + config.index + '">'
            , function () {
                var plate = [];
                config.layout.forEach(function (item, index) {
                    if (views[item]) {
                        plate.push(views[item])
                    }
                })
                return plate.join('');
            }()
            , '</div>'].join('');
    };

    //跳页的回调
    Class.prototype.jump = function (elem, isskip) {
        if (!elem) return;
        var that = this
            , config = that.config
            , childs = elem.children
            , btn = elem[tag]('button')[0]
            , input = elem[tag]('input')[0]
            , select = elem[tag]('select')[0]
            , skip = function () {
            var curr = input.value.replace(/\s|\D/g, '') | 0;
            if (curr) {
                config.curr = curr;
                that.render();
            }
        };

        if (isskip) return skip();

        //页码
        for (var i = 0, len = childs.length; i < len; i++) {
            if (childs[i].nodeName.toLowerCase() === 'a') {
                laypage.on(childs[i], 'click', function () {
                    var curr = this.getAttribute('data-page') | 0;
                    if (curr < 1 || curr > config.pages) return;
                    config.curr = curr;
                    that.render();
                });
            }
        }

        //条数
        if (select) {
            laypage.on(select, 'change', function () {
                var value = this.value;
                if (config.curr * value > config.count) {
                    config.curr = Math.ceil(config.count / value);
                }
                config.limit = value;
                that.render();
            });
        }

        //确定
        if (btn) {
            laypage.on(btn, 'click', function () {
                skip();
            });
        }
    };

    //输入页数字控制
    Class.prototype.skip = function (elem) {
        if (!elem) return;
        var that = this, input = elem[tag]('input')[0];
        if (!input) return;
        laypage.on(input, 'keyup', function (e) {
            var value = this.value
                , keyCode = e.keyCode;
            if (/^(37|38|39|40)$/.test(keyCode)) return;
            if (/\D/.test(value)) {
                this.value = value.replace(/\D/, '');
            }
            if (keyCode === 13) {
                that.jump(elem, true)
            }
        });
    };

    //渲染分页
    Class.prototype.render = function (load) {
        var that = this
            , config = that.config
            , type = that.type()
            , view = that.view();

        if (type === 2) {
            config.elem && (config.elem.innerHTML = view);
        } else if (type === 3) {
            config.elem.html(view);
        } else {
            if (doc[id](config.elem)) {
                doc[id](config.elem).innerHTML = view;
            }
        }

        config.jump && config.jump(config, load);

        var elem = doc[id]('layui-laypage-' + config.index);
        that.jump(elem);

        if (config.hash && !load) {
            location.hash = '!' + config.hash + '=' + config.curr;
        }

        that.skip(elem);
    };

    //外部接口
    window.laypage = {
        //分页渲染
        render: function (options) {
            var o = new Class(options);
            return o.index;
        }
        , index: 0
        , on: function (elem, even, fn) {
            elem.attachEvent ? elem.attachEvent('on' + even, function (e) {
                fn.call(elem, e); //for ie
            }) : elem.addEventListener(even, fn, false);
            return this;
        }
    }
})()