<?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\Driver;
use Think\Db;
defined('THINK_PATH') or exit();
/**
 * Oracle数据库驱动
 */
class Oracle extends Db{

    private     $mode         = OCI_COMMIT_ON_SUCCESS;
    private     $table        = '';
    protected   $selectSql    = 'SELECT * FROM (SELECT thinkphp.*, rownum AS numrow FROM (SELECT  %DISTINCT% %FIELD% FROM %TABLE%%JOIN%%WHERE%%GROUP%%HAVING%%ORDER%) thinkphp ) %LIMIT%%COMMENT%';

    /**
     * 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=''){
        putenv("NLS_LANG=AMERICAN_AMERICA.UTF8");
        if ( !extension_loaded('oci8') ) {
            E(L('_NOT_SUPPERT_').'oracle');
        }
        if(!empty($config)) {
            $this->config        =        $config;
            if(empty($this->config['params'])) {
                $this->config['params'] =   array();
            }
        }
    }

    /**
     * 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;
            $pconnect   = !empty($config['params']['persist'])? $config['params']['persist']:$this->pconnect;
            $conn = $pconnect ? 'oci_pconnect':'oci_new_connect';
            $this->linkID[$linkNum] = $conn($config['username'], $config['password'],$config['database']);//modify by wyfeng at 2008.12.19

            if (!$this->linkID[$linkNum]){
                $this->error(false);
            }
        }
        return $this->linkID[$linkNum];
    }

    /**
     * 释放查询结果
     * @access public
     */
     public function free() {
        oci_free_statement($this->queryID);
        $this->queryID = null;
    }

    /**
     * 执行查询 返回数据集
     * @access public
     * @param string $str  sql指令
     * @return mixed
     */
    public function query($str) {
        $this->initConnect(false);
        if ( !$this->_linkID ) return false;
        $this->queryStr = $str;
        //更改事务模式
        $this->mode = OCI_COMMIT_ON_SUCCESS;
        //释放前次的查询结果
        if ( $this->queryID ) $this->free();
        N('db_query',1);
        // 记录开始执行时间
        G('queryStartTime');
        $this->queryID = oci_parse($this->_linkID,$str);
        $this->debug();
        if (false === oci_execute($this->queryID, $this->mode)) {
            $this->error();
            return false;
        } else {
			return $this->getAll();
        }
    }

    /**
     * 执行语句
     * @access public
     * @param string $str  sql指令
     * @return integer
     */
     public function execute($str) {
        $this->initConnect(true);
        if ( !$this->_linkID ) return false;
        $this->queryStr = $str;
        // 判断新增操作
        $flag = false;
        if(preg_match("/^\s*(INSERT\s+INTO)\s+(\w+)\s+/i", $this->queryStr, $match)) {
            $this->table = C("DB_SEQUENCE_PREFIX") .str_ireplace(C("DB_PREFIX"), "", $match[2]);
            $flag = (boolean)$this->query("SELECT * FROM user_sequences WHERE sequence_name='" . strtoupper($this->table) . "'");
        }//modify by wyfeng at 2009.08.28

        //更改事务模式
        $this->mode = OCI_COMMIT_ON_SUCCESS;
        //释放前次的查询结果
        if ( $this->queryID ) $this->free();
        N('db_write',1);
        // 记录开始执行时间
        G('queryStartTime');
        $stmt = oci_parse($this->_linkID,$str);
        $this->debug();
        if (false === oci_execute($stmt)) {
            $this->error();
            return false;
        } else {
            $this->numRows = oci_num_rows($stmt);
            $this->lastInsID = $flag?$this->insertLastId():0;//modify by wyfeng at 2009.08.28
            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->mode = OCI_DEFAULT;
        }
        $this->transTimes++;
        return ;
    }

    /**
     * 用于非自动提交状态下面的查询提交
     * @access public
     * @return boolen
     */
    public function commit(){
        if ($this->transTimes > 0) {
            $result = oci_commit($this->_linkID);
            if(!$result){
                $this->error();
                return false;
            }
            $this->transTimes = 0;
        }
        return true;
    }

    /**
     * 事务回滚
     * @access public
     * @return boolen
     */
     public function rollback(){
        if ($this->transTimes > 0) {
            $result = oci_rollback($this->_linkID);
            if(!$result){
                $this->error();
                return false;
            }
            $this->transTimes = 0;
        }
        return true;
    }

    /**
     * 获得所有的查询数据
     * @access private
     * @return array
     */
     private function getAll() {
        //返回数据集
        $result = array();
        $this->numRows = oci_fetch_all($this->queryID, $result, 0, -1, OCI_FETCHSTATEMENT_BY_ROW);
		//add by wyfeng at 2008-12-23 强制将字段名转换为小写，以配合Model类函数如count等
        if(C("DB_CASE_LOWER")) {
            foreach($result as $k=>$v) {
                $result[$k] = array_change_key_case($result[$k], CASE_LOWER);
            }
        }
        return $result;
    }


    /**
     * 取得数据表的字段信息
     * @access public
     */
     public function getFields($tableName) {
        $result = $this->query("select a.column_name,data_type,decode(nullable,'Y',0,1) notnull,data_default,decode(a.column_name,b.column_name,1,0) pk "
                  ."from user_tab_columns a,(select column_name from user_constraints c,user_cons_columns col "
          ."where c.constraint_name=col.constraint_name and c.constraint_type='P'and c.table_name='".strtoupper($tableName)
          ."') b where table_name='".strtoupper($tableName)."' and a.column_name=b.column_name(+)");
        $info   =   array();
        if($result) {
            foreach ($result as $key => $val) {
                $info[strtolower($val['column_name'])] = array(
                    'name'    => strtolower($val['column_name']),
                    'type'    => strtolower($val['data_type']),
                    'notnull' => $val['notnull'],
                    'default' => $val['data_default'],
                    'primary' => $val['pk'],
                    'autoinc' => $val['pk'],
                );
            }
        }
        return $info;
    }

    /**
     * 取得数据库的表信息（暂时实现取得用户表信息）
     * @access public
     */
    public function getTables($dbName='') {
        $result = $this->query("select table_name from user_tables");
        $info   =   array();
        foreach ($result as $key => $val) {
            $info[$key] = current($val);
        }
        return $info;
    }

    /**
     * 关闭数据库
     * @access public
     */
    public function close() {
        if($this->_linkID){
            oci_close($this->_linkID);
        }
        $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($result = true) {
        if($result){
           $error = oci_error($this->queryID);
        }elseif(!$this->_linkID){
            $error = oci_error();
        }else{
            $error = oci_error($this->_linkID);
        }
        if('' != $this->queryStr){
            $error['message'] .= "\n [ SQL语句 ] : ".$this->queryStr;
        }
        $result? trace($error['message'],'','ERR'):E($error['message'],'',$error['code']);
        $this->error    =   $error['message'];
        return $this->error;
    }

    /**
     * SQL指令安全过滤
     * @access public
     * @param string $str  SQL指令
     * @return string
     */
    public function escapeString($str) {
        return str_ireplace("'", "''", $str);
    }

    /**
     * 获取最后插入id ,仅适用于采用序列+触发器结合生成ID的方式
     * 在config.php中指定
     'DB_TRIGGER_PREFIX'	=>	'tr_',
     'DB_SEQUENCE_PREFIX' =>	'ts_',
     * eg:表 tb_user
     相对tb_user的序列为：
     -- Create sequence
     create sequence TS_USER
     minvalue 1
     maxvalue 999999999999999999999999999
     start with 1
     increment by 1
     nocache;
     相对tb_user,ts_user的触发器为：
     create or replace trigger TR_USER
     before insert on "TB_USER"
     for each row
     begin
     select "TS_USER".nextval into :NEW.ID from dual;
     end;
     * @access public
     * @return integer
     */
    public function insertLastId() {
        if(empty($this->table)) {
            return 0;
        }
        $sequenceName = $this->table;
        $vo = $this->query("SELECT {$sequenceName}.currval currval FROM dual");
        return $vo?$vo[0]["currval"]:0;
    }

    /**
     * limit
     * @access public
     * @return string
     */
	public function parseLimit($limit) {
        $limitStr    = '';
        if(!empty($limit)) {
            $limit	=	explode(',',$limit);
            if(count($limit)>1)
                $limitStr = "(numrow>" . $limit[0] . ") AND (numrow<=" . ($limit[0]+$limit[1]) . ")";
            else
                $limitStr = "(numrow>0 AND numrow<=".$limit[0].")";
        }
        return $limitStr?' WHERE '.$limitStr:'';
    }
}