<?php


// +----------------------------------------------------------------------


// | ThinkPHP [ WE CAN DO IT JUST THINK IT ]


// +----------------------------------------------------------------------


// | Copyright (c) 2006-2014 http://thinkphp.cn All rights reserved.


// +----------------------------------------------------------------------


// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )


// +----------------------------------------------------------------------


// | Author: liu21st <liu21st@gmail.com>


// +----------------------------------------------------------------------





namespace Think\Db;


use Think\Config;


use Think\Debug;


use Think\Log;


use PDO;





class Lite {


    // PDO操作实例


    protected $PDOStatement = null;


    // 当前操作所属的模型名


    protected $model      = '_think_';


    // 当前SQL指令


    protected $queryStr   = '';


    protected $modelSql   = array();


    // 最后插入ID


    protected $lastInsID  = null;


    // 返回或者影响记录数


    protected $numRows    = 0;


    // 事务指令数


    protected $transTimes = 0;


    // 错误信息


    protected $error      = '';


    // 数据库连接ID 支持多个连接


    protected $linkID     = array();


    // 当前连接ID


    protected $_linkID    = null;


    // 数据库连接参数配置


    protected $config     = array(


        'type'              =>  '',     // 数据库类型


        'hostname'          =>  '127.0.0.1', // 服务器地址


        'database'          =>  '',          // 数据库名


        'username'          =>  '',      // 用户名


        'password'          =>  '',          // 密码


        'hostport'          =>  '',        // 端口     


        'dsn'               =>  '', //          


        'params'            =>  array(), // 数据库连接参数        


        'charset'           =>  'utf8',      // 数据库编码默认采用utf8  


        'prefix'            =>  '',    // 数据库表前缀


        'debug'             =>  false, // 数据库调试模式


        'deploy'            =>  0, // 数据库部署方式:0 集中式(单一服务器),1 分布式(主从服务器)


        'rw_separate'       =>  false,       // 数据库读写是否分离 主从式有效


        'master_num'        =>  1, // 读写分离后 主服务器数量


        'slave_no'          =>  '', // 指定从服务器序号


    );


    // 数据库表达式


    protected $comparison = array('eq'=>'=','neq'=>'<>','gt'=>'>','egt'=>'>=','lt'=>'<','elt'=>'<=','notlike'=>'NOT LIKE','like'=>'LIKE','in'=>'IN','notin'=>'NOT IN');


    // 查询表达式


    protected $selectSql  = 'SELECT%DISTINCT% %FIELD% FROM %TABLE%%JOIN%%WHERE%%GROUP%%HAVING%%ORDER%%LIMIT% %UNION%%COMMENT%';


    // 查询次数


    protected $queryTimes   =   0;


    // 执行次数


    protected $executeTimes =   0;


    // PDO连接参数


    protected $options = array(


        PDO::ATTR_CASE              =>  PDO::CASE_LOWER,


        PDO::ATTR_ERRMODE           =>  PDO::ERRMODE_EXCEPTION,


        PDO::ATTR_ORACLE_NULLS      =>  PDO::NULL_NATURAL,


        PDO::ATTR_STRINGIFY_FETCHES =>  false,


    );





    /**


     * 架构函数 读取数据库配置信息


     * @access public


     * @param array $config 数据库配置数组


     */


    public function __construct($config=''){


        if(!empty($config)) {


            $this->config           =   array_merge($this->config,$config);


            if(is_array($this->config['params'])){


                $this->options  +=   $this->config['params'];


            }


        }


    }





    /**


     * 连接数据库方法


     * @access public


     */


    public function connect($config='',$linkNum=0) {


        if ( !isset($this->linkID[$linkNum]) ) {


            if(empty($config))  $config =   $this->config;


            try{


                if(empty($config['dsn'])) {


                    $config['dsn']  =   $this->parseDsn($config);


                }


                if(version_compare(PHP_VERSION,'5.3.6','<=')){ //禁用模拟预处理语句


                    $this->options[PDO::ATTR_EMULATE_PREPARES]  =   false;


                }


                $this->linkID[$linkNum] = new PDO( $config['dsn'], $config['username'], $config['password'],$this->options);


            }catch (\PDOException $e) {


                E($e->getMessage());


            }


        }


        return $this->linkID[$linkNum];


    }





    /**


     * 解析pdo连接的dsn信息


     * @access public


     * @param array $config 连接信息


     * @return string


     */


    protected function parseDsn($config){}





    /**


     * 释放查询结果


     * @access public


     */


    public function free() {


        $this->PDOStatement = null;


    }





    /**


     * 执行查询 返回数据集


     * @access public


     * @param string $str  sql指令


     * @param array $bind  参数绑定


     * @return mixed


     */


    public function query($str,$bind=array()) {


        $this->initConnect(false);


        if ( !$this->_linkID ) return false;


        $this->queryStr     =   $str;


        if(!empty($bind)){


            $that   =   $this;


            $this->queryStr =   strtr($this->queryStr,array_map(function($val) use($that){ return '\''.$that->escapeString($val).'\''; },$bind));


        }


        //释放前次的查询结果


        if ( !empty($this->PDOStatement) ) $this->free();


        $this->queryTimes++;


        N('db_query',1); // 兼容代码        


        // 调试开始


        $this->debug(true);


        $this->PDOStatement = $this->_linkID->prepare($str);


        if(false === $this->PDOStatement)


            E($this->error());


        foreach ($bind as $key => $val) {


            if(is_array($val)){


                $this->PDOStatement->bindValue($key, $val[0], $val[1]);


            }else{


                $this->PDOStatement->bindValue($key, $val);


            }


        }


        $result =   $this->PDOStatement->execute();


        // 调试结束


        $this->debug(false);


        if ( false === $result ) {


            $this->error();


            return false;


        } else {


            return $this->getResult();


        }


    }





    /**


     * 执行语句


     * @access public


     * @param string $str  sql指令


     * @param array $bind  参数绑定


     * @return integer


     */


    public function execute($str,$bind=array()) {


        $this->initConnect(true);


        if ( !$this->_linkID ) return false;


        $this->queryStr = $str;


        if(!empty($bind)){


            $that   =   $this;


            $this->queryStr =   strtr($this->queryStr,array_map(function($val) use($that){ return '\''.$that->escapeString($val).'\''; },$bind));


        }      


        //释放前次的查询结果


        if ( !empty($this->PDOStatement) ) $this->free();


        $this->executeTimes++;


        N('db_write',1); // 兼容代码        


        // 记录开始执行时间


        $this->debug(true);


        $this->PDOStatement =   $this->_linkID->prepare($str);


        if(false === $this->PDOStatement) {


            E($this->error());


        }


        foreach ($bind as $key => $val) {


            if(is_array($val)){


                $this->PDOStatement->bindValue($key, $val[0], $val[1]);


            }else{


                $this->PDOStatement->bindValue($key, $val);


            }


        }


        $result =   $this->PDOStatement->execute();


        $this->debug(false);


        if ( false === $result) {


            $this->error();


            return false;


        } else {


            $this->numRows = $this->PDOStatement->rowCount();


            if(preg_match("/^\s*(INSERT\s+INTO|REPLACE\s+INTO)\s+/i", $str)) {


                $this->lastInsID = $this->_linkID->lastInsertId();


            }


            return $this->numRows;


        }


    }





    /**


     * 启动事务


     * @access public


     * @return void


     */


    public function startTrans() {


        $this->initConnect(true);


        if ( !$this->_linkID ) return false;


        //数据rollback 支持


        if ($this->transTimes == 0) {


            $this->_linkID->beginTransaction();


        }


        $this->transTimes++;


        return ;


    }





    /**


     * 用于非自动提交状态下面的查询提交


     * @access public


     * @return boolean


     */


    public function commit() {


        if ($this->transTimes > 0) {


            $result = $this->_linkID->commit();


            $this->transTimes = 0;


            if(!$result){


                $this->error();


                return false;


            }


        }


        return true;


    }





    /**


     * 事务回滚


     * @access public


     * @return boolean


     */


    public function rollback() {


        if ($this->transTimes > 0) {


            $result = $this->_linkID->rollback();


            $this->transTimes = 0;


            if(!$result){


                $this->error();


                return false;


            }


        }


        return true;


    }





    /**


     * 获得所有的查询数据


     * @access private


     * @return array


     */


    private function getResult() {


        //返回数据集


        $result =   $this->PDOStatement->fetchAll(PDO::FETCH_ASSOC);


        $this->numRows = count( $result );


        return $result;


    }





    /**


     * 获得查询次数


     * @access public


     * @param boolean $execute 是否包含所有查询


     * @return integer


     */


    public function getQueryTimes($execute=false){


        return $execute?$this->queryTimes+$this->executeTimes:$this->queryTimes;


    }





    /**


     * 获得执行次数


     * @access public


     * @return integer


     */


    public function getExecuteTimes(){


        return $this->executeTimes;


    }





    /**


     * 关闭数据库


     * @access public


     */


    public function close() {


        $this->_linkID = null;


    }





    /**


     * 数据库错误信息


     * 并显示当前的SQL语句


     * @access public


     * @return string


     */


    public function error() {


        if($this->PDOStatement) {


            $error = $this->PDOStatement->errorInfo();


            $this->error = $error[1].':'.$error[2];


        }else{


            $this->error = '';


        }


        if('' != $this->queryStr){


            $this->error .= "\n [ SQL语句 ] : ".$this->queryStr;


        }


        // 记录错误日志


        trace($this->error,'','ERR');


        if($this->config['debug']) {// 开启数据库调试模式


            E($this->error);


        }else{


            return $this->error;


        }


    }





    /**


     * 获取最近一次查询的sql语句 


     * @param string $model  模型名


     * @access public


     * @return string


     */


    public function getLastSql($model='') {


        return $model?$this->modelSql[$model]:$this->queryStr;


    }





    /**


     * 获取最近插入的ID


     * @access public


     * @return string


     */


    public function getLastInsID() {


        return $this->lastInsID;


    }





    /**


     * 获取最近的错误信息


     * @access public


     * @return string


     */


    public function getError() {


        return $this->error;


    }





    /**


     * SQL指令安全过滤


     * @access public


     * @param string $str  SQL字符串


     * @return string


     */


    public function escapeString($str) {


        return addslashes($str);


    }





    /**


     * 设置当前操作模型


     * @access public


     * @param string $model  模型名


     * @return void


     */


    public function setModel($model){


        $this->model =  $model;


    }





    /**


     * 数据库调试 记录当前SQL


     * @access protected


     * @param boolean $start  调试开始标记 true 开始 false 结束


     */


    protected function debug($start) {


        if($this->config['debug']) {// 开启数据库调试模式


            if($start) {


                G('queryStartTime');


            }else{


                $this->modelSql[$this->model]   =  $this->queryStr;


                //$this->model  =   '_think_';


                // 记录操作结束时间


                G('queryEndTime');


                trace($this->queryStr.' [ RunTime:'.G('queryStartTime','queryEndTime').'s ]','','SQL');


            }


        }


    }





    /**


     * 初始化数据库连接


     * @access protected


     * @param boolean $master 主服务器


     * @return void


     */


    protected function initConnect($master=true) {


        if(!empty($this->config['deploy']))


            // 采用分布式数据库


            $this->_linkID = $this->multiConnect($master);


        else


            // 默认单数据库


            if ( !$this->_linkID ) $this->_linkID = $this->connect();


    }





    /**


     * 连接分布式服务器


     * @access protected


     * @param boolean $master 主服务器


     * @return void


     */


    protected function multiConnect($master=false) {


        // 分布式数据库配置解析


        $_config['username']    =   explode(',',$this->config['username']);


        $_config['password']    =   explode(',',$this->config['password']);


        $_config['hostname']    =   explode(',',$this->config['hostname']);


        $_config['hostport']    =   explode(',',$this->config['hostport']);


        $_config['database']    =   explode(',',$this->config['database']);


        $_config['dsn']         =   explode(',',$this->config['dsn']);


        $_config['charset']     =   explode(',',$this->config['charset']);





        // 数据库读写是否分离


        if($this->config['rw_separate']){


            // 主从式采用读写分离


            if($master)


                // 主服务器写入


                $r  =   floor(mt_rand(0,$this->config['master_num']-1));


            else{


                if(is_numeric($this->config['slave_no'])) {// 指定服务器读


                    $r = $this->config['slave_no'];


                }else{


                    // 读操作连接从服务器


                    $r = floor(mt_rand($this->config['master_num'],count($_config['hostname'])-1));   // 每次随机连接的数据库


                }


            }


        }else{


            // 读写操作不区分服务器


            $r = floor(mt_rand(0,count($_config['hostname'])-1));   // 每次随机连接的数据库


        }


        $db_config = array(


            'username'  =>  isset($_config['username'][$r])?$_config['username'][$r]:$_config['username'][0],


            'password'  =>  isset($_config['password'][$r])?$_config['password'][$r]:$_config['password'][0],


            'hostname'  =>  isset($_config['hostname'][$r])?$_config['hostname'][$r]:$_config['hostname'][0],


            'hostport'  =>  isset($_config['hostport'][$r])?$_config['hostport'][$r]:$_config['hostport'][0],


            'database'  =>  isset($_config['database'][$r])?$_config['database'][$r]:$_config['database'][0],


            'dsn'       =>  isset($_config['dsn'][$r])?$_config['dsn'][$r]:$_config['dsn'][0],


            'charset'   =>  isset($_config['charset'][$r])?$_config['charset'][$r]:$_config['charset'][0],


        );


        return $this->connect($db_config,$r);


    }





   /**


     * 析构方法


     * @access public


     */


    public function __destruct() {


        // 释放查询


        if ($this->PDOStatement){


            $this->free();


        }


        // 关闭连接


        $this->close();


    }


}