<?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();
/**
 * Pgsql数据库驱动
 */
class Pgsql extends Db{

    /**
     * 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 ( !extension_loaded('pgsql') ) {
            E(L('_NOT_SUPPERT_').':pgsql');
        }
        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 ? 'pg_pconnect':'pg_connect';
            $this->linkID[$linkNum] =  $conn('host='.$config['hostname'].' port='.$config['hostport'].' dbname='.$config['database'].' user='.$config['username'].'  password='.$config['password']);
            if (0 !== pg_connection_status($this->linkID[$linkNum])){
                E($this->error(false));
            }
            //设置编码
            pg_set_client_encoding($this->linkID[$linkNum], $config['charset']);

        }
        return $this->linkID[$linkNum];
    }

    /**
     * 释放查询结果
     * @access public
     */
    public function free() {
        pg_free_result($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;
        //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');
        $this->queryID = pg_query($this->_linkID,$str);
        $this->debug();
        if ( false === $this->queryID ) {
            $this->error();
            return false;
        } else {
            $this->numRows = pg_num_rows($this->queryID);
            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;
        //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');
        $result =   pg_query($this->_linkID,$str);
        $this->debug();
        if ( false === $result ) {
            $this->error();
            return false;
        } else {
            $this->numRows = pg_affected_rows($result);
            $this->lastInsID =   $this->last_insert_id();
            return $this->numRows;
        }
    }

    /**
     * 用于获取最后插入的ID
     * @access public
     * @return integer
     */
    public function last_insert_id() {
        $query  =   "SELECT LASTVAL() AS insert_id";
        $result =   pg_query($this->_linkID,$query);
        list($last_insert_id)   =   pg_fetch_array($result,null,PGSQL_ASSOC);
        pg_free_result($result);
        return $last_insert_id;
    }

    /**
     * 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 ($this->transTimes == 0) {
            pg_exec($this->_linkID,'begin;');
        }
        $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) {
            $result = pg_exec($this->_linkID,'end;');
            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) {
            $result = pg_exec($this->_linkID,'abort;');
            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
        $result   =  pg_fetch_all($this->queryID);
        pg_result_seek($this->queryID,0);
        return $result;
    }

    /**
     * 取得数据表的字段信息
     * @access public
     */
    public function getFields($tableName) {
        $result   =  $this->query("select a.attname as \"Field\",
            t.typname as \"Type\",
            a.attnotnull as \"Null\",
            i.indisprimary as \"Key\",
            d.adsrc as \"Default\"
            from pg_class c
            inner join pg_attribute a on a.attrelid = c.oid
            inner join pg_type t on a.atttypid = t.oid
            left join pg_attrdef d on a.attrelid=d.adrelid and d.adnum=a.attnum
            left join pg_index i on a.attnum=ANY(i.indkey) and c.oid = i.indrelid
            where (c.relname='{$tableName}' or c.relname = lower('{$tableName}'))   AND a.attnum > 0
                order by a.attnum asc;");
        $info   =   array();
        if($result) {
            foreach ($result as $key => $val) {
                $info[$val['Field']] = array(
                'name'    => $val['Field'],
                'type'    => $val['Type'],
                'notnull' => (bool) ($val['Null'] == 't'?1:0), // 't' is 'not null'
                'default' => $val['Default'],
                'primary' => (strtolower($val['Key']) == 't'),
                'autoinc' => (strtolower($val['Default']) == "nextval('{$tableName}_id_seq'::regclass)"),
                );
            }
        }
        return $info;
    }

    /**
     * 取得数据库的表信息
     * @access public
     */
    public function getTables($dbName='') {
        $result = $this->query("select tablename as Tables_in_test from pg_tables where  schemaname ='public'");
        $info   =   array();
        foreach ($result as $key => $val) {
            $info[$key] = current($val);
        }
        return $info;
    }

    /**
     * 关闭数据库
     * @access public
     */
    public function close() {
        if($this->_linkID){
            pg_close($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) {
        $this->error = $result?pg_result_error($this->queryID): pg_last_error($this->_linkID);
        if('' != $this->queryStr){
            $this->error .= "\n [ SQL语句 ] : ".$this->queryStr;
        }
        trace($this->error,'','ERR');
        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 pg_escape_string($str);
    }

    /**
     * limit
     * @access public
     * @return string
     */
    public function parseLimit($limit) {
        $limitStr    = '';
        if(!empty($limit)) {
            $limit  =   explode(',',$limit);
            if(count($limit)>1) {
                $limitStr .= ' LIMIT '.$limit[1].' OFFSET '.$limit[0].' ';
            }else{
                $limitStr .= ' LIMIT '.$limit[0].' ';
            }
        }
        return $limitStr;
    }
}