var isIE = (document.all) ? true : false;
var $$$ = function (id) {
    return "string" == typeof id ? document.getElementById(id) : id;
};

var Class = {
  create: function() {
    return function() {
      this.initialize.apply(this, arguments);
    }
  }
}

var Extend = function(destination, source) {
	for (var property in source) {
		destination[property] = source[property];
	}
}

var Bind = function(object, fun) {
	return function() {
		return fun.apply(object, arguments);
	}
}

var Each = function(list, fun){
	for (var i = 0, len = list.length; i < len; i++) { fun(list[i], i); }
};

//文件上传类
var FileUpload = Class.create();
FileUpload.prototype = {
    //表单对象，文件控件存放空间
    initialize: function(form, folder, options) {

        this.Form = $$$(form); //表单
        this.Folder = $$$(folder); //文件控件存放空间
        this.Files = []; //文件集合
        this.SetOptions(options);
        this.FileName = this.options.FileName;
        this._FrameName = this.options.FrameName;
        this.Limit = this.options.Limit;
        this.Distinct = !!this.options.Distinct;
        this.ExtIn = this.options.ExtIn;
        this.ExtOut = this.options.ExtOut;
        this.onIniFile = this.options.onIniFile;
        this.onEmpty = this.options.onEmpty;
        this.onNotExtIn = this.options.onNotExtIn;
        this.onExtOut = this.options.onExtOut;
        this.onLimite = this.options.onLimite;
        this.onSame = this.options.onSame;
        this.onFail = this.options.onFail;
        this.onIni = this.options.onIni;

        if (!this._FrameName) {
            //为每个实例创建不同的iframe
            this._FrameName = "uploadFrame_" + Math.floor(Math.random() * 1000);
            //ie不能修改iframe的name
            var oFrame = isIE ? document.createElement("<iframe name=\"" + this._FrameName + "\">") : document.createElement("iframe");
            //为ff设置name
            oFrame.name = this._FrameName;
            oFrame.style.display = "none";
            //在ie文档未加载完用appendChild会报错
            //document.body.insertBefore(oFrame, document.body.childNodes[0]);
        }
        //设置form属性，关键是target要指向iframe
        this.Form.target = this._FrameName;
        this.Form.method = "post";
        //注意ie的form没有enctype属性，要用encoding
        this.Form.encoding = "multipart/form-data";
        //整理一次
        this.Ini();
    },
    //设置默认属性
    SetOptions: function(options) {
        this.options = {//默认值
            FileName: "", //文件上传控件的name，配合后台使用
            FrameName: "", //iframe的name，要自定义iframe的话这里设置name
            onIniFile: function() { }, //整理文件时执行(其中参数是file对象)
            onEmpty: function() { }, //文件空值时执行
            Limit: 0, //文件数限制，0为不限制
            onLimite: function() { }, //超过文件数限制时执行
            Distinct: true, //是否不允许相同文件
            onSame: function() { }, //有相同文件时执行
            ExtIn: [], //允许后缀名
            onNotExtIn: function() { }, //不是允许后缀名时执行
            ExtOut: [], //禁止后缀名，当设置了ExtIn则ExtOut无效
            onExtOut: function() { }, //是禁止后缀名时执行
            onFail: function() { }, //文件不通过检测时执行(其中参数是file对象)
            onIni: function() { } //重置时执行
        };
        Extend(this.options, options || {});
    },
    //整理空间
    Ini: function() {
        //整理文件集合
        this.Files = [];
        //整理文件空间，把有值的file放入文件集合
        Each(this.Folder.getElementsByTagName("input"), Bind(this, function(o) {
            if (o.type == "file") { o.value && this.Files.push(o); this.onIniFile(o); }
        }))
        //插入一个新的file
        var file = document.createElement("input");
        file.name = this.FileName; file.type = "file"; file.onchange = Bind(this, function() { this.Check(file); this.Ini(); });
        this.Folder.appendChild(file);
        alert($(this.Folder).html());
        //执行附加程序
        this.onIni();
    },
    //检测file对象
    Check: function(file) {
        //检测变量
        var bCheck = true;
        //空值、文件数限制、后缀名、相同文件检测
        if (!file.value) {
            bCheck = false; this.onEmpty();
        } else if (this.Limit && this.Files.length >= this.Limit) {
            bCheck = false; this.onLimite();
        } else if (!!this.ExtIn.length && !RegExp("\.(" + this.ExtIn.join("|") + ")$$$", "i").test(file.value)) {
            //检测是否允许后缀名
            bCheck = false; this.onNotExtIn();
        } else if (!!this.ExtOut.length && RegExp("\.(" + this.ExtOut.join("|") + ")$$$", "i").test(file.value)) {
            //检测是否禁止后缀名
            bCheck = false; this.onExtOut();
        } else if (!!this.Distinct) {
            Each(this.Files, function(o) { if (o.value == file.value) { bCheck = false; } })
            if (!bCheck) { this.onSame(); }
        }
        //没有通过检测
        !bCheck && this.onFail(file);
    },
    //删除指定file
    Delete: function(file) {
        //移除指定file
        this.Folder.removeChild(file); this.Ini();
    },
    //删除全部file
    Clear: function() {
        //清空文件空间
        Each(this.Files, Bind(this, function(o) { this.Folder.removeChild(o); })); this.Ini();
    }
}

var fu = new FileUpload("uploadForm", "idFile", { Limit: 3, ExtIn: ["jpg", "gif", "doc", "xls", "ppt", "rar"],
	onIniFile: function(file){ file.value ? file.style.display = "none" : this.Folder.removeChild(file); },
	onEmpty: function(){ alert("请选择一个文件"); },
	onLimite: function(){ alert("超过上传限制"); },
	onSame: function(){ alert("已经有相同文件"); },
	onNotExtIn:	function(){ alert("只允许上传" + this.ExtIn.join("，") + "文件"); },
	onFail: function(file){ this.Folder.removeChild(file); },
	onIni: function(){
		//显示文件列表
		var arrRows = [];
		if(this.Files.length){
			var oThis = this;
			Each(this.Files, function(o){
				var a = document.createElement("a"); a.innerHTML = "取消"; a.href = "javascript:void(0);";
				a.onclick = function() { oThis.Delete(o); return false; };
				arrRows.push([o.value, a]);
			});
		} else { arrRows.push(["<font color='gray'>没有添加文件</font>", "&nbsp;"]); }
		AddList(arrRows);
		//设置按钮
		$$$("idBtnupload").disabled = $$$("idBtndel").disabled = this.Files.length <= 0;
	}
});

$("#idBtnupload").onclick = function() {
	//显示文件列表
	var arrRows = [];
	Each(fu.Files, function(o){ arrRows.push([o.value, "&nbsp;"]); });
	AddList(arrRows);
	
	fu.Folder.style.display = "none";
	$$$("idProcess").style.display = "";
	$$$("idMsg").innerHTML = "文件正在上传中&nbsp;&nbsp;<img src='/images/loadingAnimation.gif' />请稍候……<br />有可能因为网络问题，出现程序长时间无响应，请点击“<a href='?'><font color='red'>取消</font></a>”重新上传文件";
	fu.Form.submit();
}

//用来添加文件列表的函数
function AddList(rows){
	//根据数组来添加列表
	var FileList = $$$("idFileList"), oFragment = document.createDocumentFragment();
	//用文档碎片保存列表
	Each(rows, function(cells){
		var row = document.createElement("tr");
		Each(cells, function(o){
			var cell = document.createElement("td");
			if(typeof o == "string"){ cell.innerHTML = o; }else{ cell.appendChild(o); }
			row.appendChild(cell);
		});
		oFragment.appendChild(row);
	})
	//ie的table不支持innerHTML所以这样清空table
	while(FileList.hasChildNodes()){ FileList.removeChild(FileList.firstChild); }
	FileList.appendChild(oFragment);
}

$$$("idLimit").innerHTML = fu.Limit;
$$$("idExt").innerHTML = fu.ExtIn.join("，");
$$$("idBtndel").onclick = function(){ fu.Clear(); }
