/**
 * mysql socket
 * @return {[type]} [description]
 */

//暂时使用mysql库
var mysql = require("mysql");
module.exports = Class(function(){
    "use strict";
    return {
        handle: null,
        config: null,
        deferred: null,
        init: function(config){
            this.handle = null;
            this.config = config;
            this.deferred = null;
        },
        /**
         * 建立数据库连接
         * @return {[type]} [description]
         */
        connect: function(){
            if (this.handle) {
                return true;
            }
            var self = this;
            var deferred = getDefer();
            //创建连接
            var connection = mysql.createConnection({
                host     : this.config.hostname || "localhost",
                user     : this.config.username || "root",
                password : this.config.password || "",
                database : this.config.database || ""
            });
            //连接
            connection.connect(function(err){
                //连接失败
                if (err) {
                    deferred.reject(err);
                    self.close();
                }else{
                    deferred.resolve();
                }
            });
            //错误时关闭当前连接
            connection.on("error", function(){
                self.close();
            });
            //连接句柄
            this.handle = connection;
            //把上一次的promise resolve
            if (this.deferred) {
                this.deferred.resolve();
            }
            this.deferred = deferred;
        },
        /**
         * 查询sql语句，返回一个promise
         * @param  {[type]} sql [description]
         * @return {[type]}     [description]
         */
        query: function(sql){
            if (APP_DEBUG) {
                console.log("sql: " + sql);
            }
            var self = this;
            self.connect();
            return this.deferred.promise.then(function(){
                var deferred = getDefer();
                self.handle.query(sql, function(err, rows){
                    if (err) {
                        return deferred.reject(err);
                    }
                    return deferred.resolve(rows || []);
                });
                return deferred.promise;
            });
        },
        /**
         * 关闭连接
         * @return {[type]} [description]
         */
        close: function(){
            if (this.handle) {
                this.handle.destroy();
                this.handle = null;
            }
        }
    };
});