<?php
namespace lib;

class PdoHelper
{
    private $sqlPrefix = "pre_";//SQL数据表前缀识别字符
    private $db;
    private $fetchStyle = \PDO::FETCH_ASSOC;
    private $prefix;

    /**
     * PdoHelper constructor.
     *
     * @param array $dbconfig 数据库信息
     */
    function __construct($dbconfig)
    {
        $this->prefix = $dbconfig['dbqz'].'_';
        try {
            $this->db = new \PDO("mysql:host={$dbconfig['host']};dbname={$dbconfig['dbname']};port={$dbconfig['port']}",$dbconfig['user'],$dbconfig['pwd']);
        } catch (Exception $e) {
            exit('链接数据库失败:' . $e->getMessage());
        }
        $this->db->exec("set sql_mode = ''");
        $this->db->exec("set names utf8");
    }

    /**
     * 设置结果集方式
     *
     * @param string $_style
     */
    public function setFetchStyle($_style)
    {
        $this->fetchStyle = $_style;
    }

    /**
     * 替换数据表前缀
     * @param $_sql
     *
     * @return mixed
     */
    private function dealPrefix($_sql){
        return str_replace($this->sqlPrefix,$this->prefix,$_sql);
    }

    /**
     * 获取PDOStatement
     * @param string $_sql
     * @param array $_array
     *
     * @return \PDOStatement
     */
    public function query($_sql, $_array = null)
    {
        $_sql = $this->dealPrefix($_sql);
        if (is_array($_array)) {
            $stmt = $this->db->prepare($_sql);
            if($stmt) $stmt->execute($_array);
        } else {
            $stmt = $this->db->query($_sql);
        }
        return $stmt;
    }

    /**
     * 查询一条结果
     *
     * @param string $_sql string
     * @param array $_array array
     *
     * @return mixed
     */
    public function getRow($_sql, $_array = null)
    {
        $_sql = $this->dealPrefix($_sql);
        if (is_array($_array)) {
            $stmt = $this->db->prepare($_sql);
            if($stmt) $stmt->execute($_array);
        } else {
            $stmt = $this->db->query($_sql);
        }
        if($stmt) {
            return $stmt->fetch($this->fetchStyle);
        }else{
            return false;
        }
    }

    /**
     * 获取所有结果
     *
     * @param string $_sql
     * @param array $_array
     *
     * @return array
     */
    public function getAll($_sql, $_array = null)
    {
        $_sql = $this->dealPrefix($_sql);
        if (is_array($_array)) {
            $stmt = $this->db->prepare($_sql);
            if($stmt) $stmt->execute($_array);
        } else {
            $stmt = $this->db->query($_sql);
        }
        if($stmt) {
            return $stmt->fetchAll($this->fetchStyle);
        }else{
            return false;
        }
    }

    /**
     * 获取结果数
     * @param string $_sql
     * @param array $_array
     *
     * @return int
     */
    public function getCount($_sql, $_array = null)
    {
        $_sql = $this->dealPrefix($_sql);
        $stmt = $this->db->prepare($_sql);
        if($stmt) {
            $stmt->execute($_array);
            return $stmt->rowCount();
        }else{
            return false;
        }
    }

    /**
     * 获取一个字段值
     * @param string $_sql
     * @param array $_array
     *
     * @return int
     */
    public function getColumn($_sql, $_array = null)
    {
        $_sql = $this->dealPrefix($_sql);
        if (is_array($_array)) {
            $stmt = $this->db->prepare($_sql);
            if($stmt) $stmt->execute($_array);
        } else {
            $stmt = $this->db->query($_sql);
        }
        if($stmt) {
            return $stmt->fetchColumn();
        }else{
            return false;
        }
    }

    /**
     * 执行语句
     * @param string $_sql
     * @param array $_array
     *
     * @return int|\PDOStatement
     */
    public function exec($_sql, $_array = null)
    {
        $_sql = $this->dealPrefix($_sql);
        if (is_array($_array)) {
            $stmt = $this->db->prepare($_sql);
            if($stmt) {
                return $stmt->execute($_array);
            }else{
                return false;
            }
        } else {
            return $this->db->exec($_sql);
        }
    }

    /**
     * 返回最后插入行的ID
     *
     * @return int|\PDOStatement
     */
    public function lastInsertId()
    {
        return $this->db->lastInsertId();
    }

    /**
     * 返回错误信息
     *
     * @return string|\PDOStatement
     */
    public function error()
    {
        $error = $this->db->errorInfo();
        return '['.$error[1].']'.$error[2];
    }

    function __get($name)
    {
        return $this->$name;
    }

    function __destruct()
    {
        $this->db = null;
    }


}