<?php
// +----------------------------------------------------------------------
// | ThinkPHP [ WE CAN DO IT JUST THINK ]
// +----------------------------------------------------------------------
// | Copyright (c) 2006~2016 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\Driver;

/**
 * mysql数据库驱动
 */
class Mysql extends Driver
{

    /**
     * 解析pdo连接的dsn信息
     * @access public
     * @param array $config 连接信息
     * @return string
     */
    protected function parseDsn($config)
    {
        $dsn = 'mysql:dbname=' . $config['database'] . ';host=' . $config['hostname'];
        if (!empty($config['hostport'])) {
            $dsn .= ';port=' . $config['hostport'];
        } elseif (!empty($config['socket'])) {
            $dsn .= ';unix_socket=' . $config['socket'];
        }
        if (!empty($config['charset'])) {
            $dsn .= ';charset=' . $config['charset'];
        }
        return $dsn;
    }

    /**
     * 取得数据表的字段信息
     * @access public
     * @param $tableName
     *
     * @return array
     */
    public function getFields($tableName)
    {
        $this->initConnect(true);
        list($tableName) = explode(' ', $tableName);
        $sql             = 'SHOW COLUMNS FROM `' . $tableName . '`';
        $result          = $this->query($sql);
        $info            = [];
        if ($result) {
            foreach ($result as $key => $val) {
                $info[$val['field']] = [
                    'name'    => $val['field'],
                    'type'    => $val['type'],
                    'notnull' => (bool) ('' === $val['null']), // not null is empty, null is yes
                    'default' => $val['default'],
                    'primary' => (strtolower($val['key']) == 'pri'),
                    'autoinc' => (strtolower($val['extra']) == 'auto_increment'),
                ];
            }
        }
        return $info;
    }

    /**
     * 取得数据库的表信息
     * @access public
     *
     * @param string $dbName
     *
     * @return array
     */
    public function getTables($dbName = '')
    {
        $sql    = !empty($dbName) ? 'SHOW TABLES FROM ' . $dbName : 'SHOW TABLES ';
        $result = $this->query($sql);
        $info   = [];
        foreach ($result as $key => $val) {
            $info[$key] = current($val);
        }
        return $info;
    }

    /**
     * 字段和表名处理
     * @access protected
     * @param string $key
     * @return string
     */
    protected function parseKey(&$key)
    {
        $key = trim($key);
        if (strpos($key, '$.') && false === strpos($key, '(')) {
            // JSON字段支持
            list($field, $name) = explode($key, '$.');
            $key                = 'jsn_extract(' . $field . ', \'$.\'.' . $name . ')';
        }
        if (!preg_match('/[,\'\"\*\(\)`.\s]/', $key)) {
            $key = '`' . $key . '`';
        }
        return $key;
    }


    /**
     * 随机排序
     * @access protected
     * @return string
     */
    protected function parseRand()
    {
        return 'rand()';
    }
}