<?php

class PDO_DB {

        protected static $_dbh = null; //静态属性,所有数据库实例共用,避免重复连接数据库
        protected $_dbType = 'mysql';
        protected $_pconnect = true; //是否使用长连接
        protected $_host = 'localhost';
        protected $_port = 3306;
        protected $_user = 'root';
        protected $_pass = 'root';
        protected $_dbName = 'tbk_onlive'; //数据库名
        protected $_sql = false; //最后一条sql语句
        protected $_where = '';
        protected $_order = '';
        protected $_limit = '';
        protected $_field = '*';
        protected $_tbName = '*';
        protected $_clear = 0; //状态，0表示查询条件干净，1表示查询条件污染
        protected $_trans = 0; //事务指令数 

        /**
         * 初始化类
         * @param array $conf 数据库配置
         */
        public function __construct(array $conf) {
            class_exists('PDO') or die("PDO: class not exists.");
            $this->_host = $conf['host'];
            $this->_port = $conf['port'];
            $this->_user = $conf['user'];
            $this->_pass = $conf['password'];
            $this->_dbName = $conf['dbName'];
            //连接数据库
            if ( is_null(self::$_dbh) ) {
                $this->_connect();
            }
        }

        /**
         * 连接数据库的方法
         */
        protected function _connect() {
            $dsn = $this->_dbType.':host='.$this->_host.';port='.$this->_port.';dbname='.$this->_dbName;
            //持久化连接
            $options = $this->_pconnect ? array(PDO::ATTR_PERSISTENT=>true) : array();
            try { 
                $dbh = new PDO($dsn, $this->_user, $this->_pass, $options);
                $dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);  //设置如果sql语句执行错误则抛出异常，事务会自动回滚
                $dbh->setAttribute(PDO::ATTR_EMULATE_PREPARES, false); //禁用prepared statements的仿真效果(防SQL注入)
            } catch (PDOException $e) { 
                die('Connection failed: ' . $e->getMessage());
            }
            $dbh->exec('SET NAMES utf8');
            self::$_dbh = $dbh;
        }

        /** 
        * 字段和表名添加 `符号
        * 保证指令中使用关键字不出错 针对mysql 
        * @param string $value 
        * @return string 
        */
        protected function _addChar($value) { 
            if ('*'==$value || false!==strpos($value,'(') || false!==strpos($value,'.') || false!==strpos($value,'`')) { 
                //如果包含* 或者 使用了sql方法 则不作处理 
            } elseif (false === strpos($value,'`') ) { 
                $value = '`'.trim($value).'`';
            } 
            return $value; 
        }

        /** 
        * 取得数据表的字段信息 
        * @param string $tbName 表名
        * @return array 
        */
        protected function _tbFields($tbName) {
            $sql = 'SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME="'.$tbName.'" AND TABLE_SCHEMA="'.$this->_dbName.'"';
            $stmt = self::$_dbh->prepare($sql);
            $stmt->execute();
            $result = $stmt->fetchAll(PDO::FETCH_ASSOC);
            $ret = array();
            foreach ($result as $key=>$value) {
                $ret[$value['COLUMN_NAME']] = 1;
            }
            return $ret;
        }

        /** 
        * 过滤并格式化数据表字段
        * @param string $tbName 数据表名 
        * @param array $data POST提交数据 
        * @return array $newdata 
        */
        protected function _dataFormat($tbName,$data) {
            if (!is_array($data)) return array();
            $table_column = $this->_tbFields($tbName);
            $ret=array();
            foreach ($data as $key=>$val) {
                if (!is_scalar($val)) continue; //值不是标量则跳过
                if (array_key_exists($key,$table_column)) {
                    $key = $this->_addChar($key);
                    if (is_int($val)) { 
                        $val = intval($val); 
                    } elseif (is_float($val)) { 
                        $val = floatval($val); 
                    } elseif (preg_match('/^\(\w*(\+|\-|\*|\/)?\w*\)$/i', $val)) {
                        // 支持在字段的值里面直接使用其它字段 ,例如 (score+1) (name) 必须包含括号
                        $val = $val;
                    } elseif (is_string($val)) { 
                        //将字符串中的单引号（'）、双引号（"）、反斜线（\）与 NUL（NULL 字符转义
                        $val = '"'.addslashes($val).'"';
                    }
                    $ret[$key] = $val;
                }
            }
            return $ret;
        }

        /**
        * 执行查询 主要针对 SELECT, SHOW 等指令
        * @param string $sql sql指令 
        * @return mixed 
        */
        protected function _doQuery($sql='') {
            $this->_sql = $sql;
            $pdostmt = self::$_dbh->prepare($this->_sql); //prepare或者query 返回一个PDOStatement
            $pdostmt->execute();
            $result = $pdostmt->fetchAll(PDO::FETCH_ASSOC);
            return $result;
        }

        /** 
        * 执行语句 针对 INSERT, UPDATE 以及DELETE,exec结果返回受影响的行数
        * @param string $sql sql指令 
        * @return integer 
        */
        protected function _doExec($sql='') {
            $this->_sql = $sql;
            return self::$_dbh->exec($this->_sql);
        }

        /** 
        * 执行sql语句，自动判断进行查询或者执行操作 
        * @param string $sql SQL指令 
        * @return mixed 
        */
        public function doSql($sql='') {
            $queryIps = 'INSERT|UPDATE|DELETE|REPLACE|CREATE|DROP|LOAD DATA|SELECT .* INTO|COPY|ALTER|GRANT|REVOKE|LOCK|UNLOCK'; 
            if (preg_match('/^\s*"?(' . $queryIps . ')\s+/i', $sql)) { 
                return $this->_doExec($sql);
            }
            else {
                //查询操作
                return $this->_doQuery($sql);
            }
        }

        /** 
        * 获取最近一次查询的sql语句 
        * @return String 执行的SQL 
        */
        public function getLastSql() { 
            return $this->_sql;
        }

        /**
         * 插入方法
         * @param string $tbName 操作的数据表名
         * @param array $data 字段-值的一维数组
         * @return int 受影响的行数
         */
        public function insert(array $data){
            $data = $this->_dataFormat($this->_tbName,$data);
            if (!$data) return;
            $sql = "insert into ".$this->_tbName."(".implode(',',array_keys($data)).") values(".implode(',',array_values($data)).")";
            return $this->_doExec($sql);
        }

        /**
         * 删除方法
         * @param string $tbName 操作的数据表名
         * @return int 受影响的行数
         */
        public function delete() {
            //安全考虑,阻止全表删除
            if (!trim($this->_where)) return false;
            $sql = "delete from ".$this->_tbName." ".$this->_where;
            $this->_clear = 1;
            $this->_clear();
            return $this->_doExec($sql);
        }

        /**
         * 更新函数
         * @param string $tbName 操作的数据表名
         * @param array $data 参数数组
         * @return int 受影响的行数
         */
        public function update(array $data) {
            //安全考虑,阻止全表更新
            if (!trim($this->_where)) return false;
            $data = $this->_dataFormat($this->_tbName,$data);
            if (!$data) return;
            $valArr = [];
            foreach($data as $k=>$v){
                $valArr[] = $k.'='.$v;
            }
            $valStr = implode(',', $valArr);
            $sql = "update ".trim($this->_tbName)." set ".trim($valStr)." ".trim($this->_where);
            return $this->_doExec($sql);
        }

        /**
         * 查询函数
         * @param string $tbName 操作的数据表名
         * @return array 结果集
         */
        public function get() {
            $sql = "select ".trim($this->_field)." from ".$this->_tbName." ".trim($this->_where)." ".trim($this->_order)." ".trim($this->_limit);

            $this->_clear = 1;
            $this->_clear();
            return $this->_doQuery(trim($sql));
        }

        /**
         * 查询函数
         * @param string $tbName 操作的数据表名
         * @return array 结果集
         */
        public function first() {
            $sql = "select ".trim($this->_field)." from ".$this->_tbName." ".trim($this->_where)." ".trim($this->_order)." limit 1 ";

            $this->_clear = 1;
            $this->_clear();
            $this->_sql = $sql;
            $pdostmt = self::$_dbh->prepare($this->_sql); //prepare或者query 返回一个PDOStatement
            $pdostmt->execute();
            $result = $pdostmt->fetch(PDO::FETCH_ASSOC);
            return $result;
        }

        public function table($table){
            if ($this->_clear>0) $this->_clear();
            $this->_tbName = $table;
            return $this;
        }

        /**
         * @param mixed $option 组合条件的二维数组，例：$option['field1'] = array(1,'=>','or')
         * @return $this
         */
        public function where($option) {
            if ($this->_clear>0) $this->_clear();
            $this->_where = ' where ';
            $logic = 'and';
            if (is_string($option)) {
                $this->_where .= $option;
            }
            elseif (is_array($option)) {
                foreach($option as $k=>$v) {
                    if (is_array($v)) {
                        $relative = isset($v[1]) ? $v[1] : '=';
                        $logic    = isset($v[2]) ? $v[2] : 'and';
                        if(!is_numeric($v[0])){
                            $v[0] = "'".$v[0]."'";
                        }
                        $condition = ' ('.$this->_addChar($k).' '.$relative.' '.$v[0].') ';
                    }
                    else {
                        if(!is_numeric($v)){
                            $v = "'".$v."'";
                        }
                        $logic = 'and';
                        $condition = ' ('.$this->_addChar($k).'='.$v.') ';
                    }
                    $this->_where .= isset($mark) ? $logic.$condition : $condition;
                    $mark = 1;
                }
            }
            return $this;
        }

        /**
         * 设置排序
         * @param mixed $option 排序条件数组 例:array('sort'=>'desc')
         * @return $this
         */
        public function orderBy($option, $fl='') {
            if ($this->_clear>0) $this->_clear();
            $this->_order = ' order by ';
            if (is_string($option)) {
                $this->_order .= $option. ' ' .$fl;
            }
            elseif (is_array($option)) {
                foreach($option as $k=>$v){
                    $order = $this->_addChar($k).' '.$v;
                    $this->_order .= isset($mark) ? ','.$order : $order;
                    $mark = 1;
                }
            }
            return $this;
        }

        /**
         * 设置查询行数及页数
         * @param int $page pageSize不为空时为页数，否则为行数
         * @param int $pageSize 为空则函数设定取出行数，不为空则设定取出行数及页数
         * @return $this
         */
        public function limit($limit, $offset=null) {
            if ($this->_clear>0) $this->_clear();
            if ($offset===null) {
                $this->_limit = "limit ".$limit;
            }
            else {
                $this->_limit = "limit ".$limit.",".$offset;
            }
            return $this;
        }

        /**
         * 设置查询字段
         * @param mixed $field 字段数组
         * @return $this
         */
        public function select($field){
            if ($this->_clear>0) $this->_clear();
            #假如是sql，直接执行
            $queryIps = 'SELECT|INSERT|UPDATE|DELETE|REPLACE|CREATE|DROP|LOAD DATA|SELECT .* INTO|COPY|ALTER|GRANT|REVOKE|LOCK|UNLOCK'; 
            if (preg_match('/^\s*"?(' . $queryIps . ')\s+/i', $field)) { 
                return $this->doSql($field);
            }

            if (is_string($field)) {
                $field = explode(',', $field);
            }
            $nField = array_map(array($this,'_addChar'), $field);
            $this->_field = implode(',', $nField);
            return $this;
        }

        /**
         * 清理标记函数
         */
        protected function _clear() {
            $this->_where = '';
            $this->_order = '';
            $this->_limit = '';
            $this->_field = '*';
            $this->_clear = 0;
        }

        /**
         * 手动清理标记
         * @return $this
         */
        public function clearKey() {
            $this->_clear();
            return $this;
        }

        /**
        * 启动事务 
        * @return void 
        */
        public function startTrans() { 
            //数据rollback 支持 
            if ($this->_trans==0) self::$_dbh->beginTransaction();
            $this->_trans++; 
            return; 
        }

        /** 
        * 用于非自动提交状态下面的查询提交 
        * @return boolen 
        */
        public function commit() {
            $result = true;
            if ($this->_trans>0) { 
                $result = self::$_dbh->commit(); 
                $this->_trans = 0;
            } 
            return $result;
        }

        /** 
        * 事务回滚 
        * @return boolen 
        */
        public function rollback() {
            $result = true;
            if ($this->_trans>0) {
                $result = self::$_dbh->rollback();
                $this->_trans = 0;
            }
            return $result;
        }

        /**
        * 关闭连接
        * PHP 在脚本结束时会自动关闭连接。
        */
        public function close() {
            if (!is_null(self::$_dbh)) self::$_dbh = null;
        }

}