/**
 * 定义一个类型
 * @constructor
 */

var thisObj;
function Tree() {
    this.Items = {};
    this.PItems = [];
    this.args = arguments; //层级对象ID
    this.selectValue = "id"; //设置对象的值是id,还是text
    thisObj = this;
}

Tree.prototype.add = function(id,iArray){
    this.Items[id] = iArray;
}

Tree.prototype.addItem = function (pid, id, name) {
    this.Items[id] = {"id":id, "pid":pid, "name":name};

    if(typeof(this.PItems[pid]) == "undefined") this.PItems[pid] = new Array();
    this.PItems[pid].push(id);

}

Tree.prototype.Exists = function(id){
    if(typeof(this.Items[id]) == "undefined") return false;
    return true;
}

Tree.prototype.ExistsByPid = function (pid) {
    if(typeof(this.PItems[pid]) == "undefined") return false;
    return true;
}

Tree.prototype.getItemsById = function (id) {
    if(typeof(this.Items[id]) == "undefined") return [];

    return this.getItemsByPid(this.Items[id]["pid"]);
}

Tree.prototype.getItemsByPid = function (pid) {
    var data = [];
    if(typeof(this.PItems[pid]) == "undefined") return data;

    var _id_;
    for(var i = 0; i < this.PItems[pid].length; i++) {
        _id_ = this.PItems[pid][i];
        data.push(this.Items[_id_]);
    }
    return data;
}

Tree.prototype.bindEvent = function () {
    if(!this.args || this.args.length==0) return;

    for(var i=0; i < this.args.length; i++){
        document.getElementById(this.args[i]).addEventListener("change", thisObj.setSelectItems(this.args[i]), false);
    }
}

Tree.prototype.test = function (index) {
    alert(index);
}

Tree.prototype.getSelectedValue = function (objectId) {
    return document.getElementById(objectId).value;
}

Tree.prototype.setSelectedValue = function (objSelect, val) {
    for (var i = 0; i < objSelect.options.length; i++) {
        if (objSelect.options[i].value == val) {
            objSelect.options[i].selected = true;
            return true;
        }
    }
    return false;
}

Tree.prototype.setSelectItems = function (objectId, selectId) {
    if(!document.getElementById(objectId)) return;
    var pidIndex=0, idIndex=0;
    for(var i=0; i < this.args.length; i++){
        if(objectId==this.args[i]){
            if(idIndex>0) pidIndex = idIndex-1;
            else pidIndex=0;
            break;
        }
        idIndex++;
    }

    //移除后面的值
    for(var i=idIndex; i < this.args.length; i++){
        this.clearSelectItems(document.getElementById(this.args[i]), 1);
    }

    //alert("idIndex="+idIndex+",pidIndex="+pidIndex)
    //取得上级pid值
    var pid = 0;
    if(idIndex!=0) pid = this.getSelectedValue(this.args[pidIndex]);
    this.addSelectItems(document.getElementById(this.args[idIndex]), pid, undefined, false);

    //设置当前选择项的选中值
    if(this.setSelectedValue(document.getElementById(this.args[idIndex]), selectId) && idIndex < this.args.length){
        this.addSelectItems(document.getElementById(this.args[idIndex+1]), selectId, undefined, true)
    }
}

Tree.prototype.clearSelectItems = function (objSelect, offset) {
    if(!objSelect || !objSelect.options) return;
    var maxIndex = objSelect.options.length-1;
    if(maxIndex==0 || maxIndex < offset ) return;

    for (var i = maxIndex; i > offset-1; i--) {
        objSelect.options.remove(i)
    }
}

Tree.prototype.addSelectItems = function (objSelect, pid, selectId, append) {
    //需要先移除原来的选项
    append = append||false;
    if(append) this.clearSelectItems(objSelect, 1);

    //如果没有pid数据,直接返回
    if(!this.ExistsByPid(pid) || this.PItems[pid].length==0) return;

    //加入选择项
    var count = this.PItems[pid].length;
    var _id_
    for(var i=0; i < count; i++) {
        _id_ = this.PItems[pid][i];
        var varItem = new Option(this.Items[_id_]["name"], this.Items[_id_]["id"]);
        objSelect.options.add(varItem);
    }

    //设置选中值
    if(selectId)
        this.setSelectedValue(objSelect, selectId);
}

Tree.prototype.show = function () {
    //如果有参数则重新绑定对象
    if(arguments && arguments.length>0) this.args = arguments;

    //无对象ID则退出
    if(!this.args || this.args.length==0) return;

    this.setSelectItems(this.args[0],undefined);

    //this.bindEvent();
}


/////////////// 下面为具体数据　///////////////////////

///投保区域选择
var area_tree = new Tree("area_province","area_city");
area_tree.addItem("0", "12", "上海");
area_tree.addItem("12", "13", "上海全市");
area_tree.addItem("0", "1", "浙江省");
area_tree.addItem("1", "3", "杭州市");
area_tree.addItem("1", "11", "湖州市");
area_tree.addItem("1", "7", "嘉兴市");
area_tree.addItem("1", "10", "金华市");
area_tree.addItem("1", "8", "丽水市");
area_tree.addItem("1", "5", "宁波市");
area_tree.addItem("1", "6", "绍兴市");
area_tree.addItem("1", "9", "台州市");
area_tree.addItem("1", "4", "温州市");
area_tree.show();