<?php
// +----------------------------------------------------------------------
// | TOPThink [ WE CAN DO IT JUST THINK ]
// +----------------------------------------------------------------------
// | Copyright (c) 2011 http://topthink.com All rights reserved.
// +----------------------------------------------------------------------
// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )
// +----------------------------------------------------------------------
// | Author: liu21st <liu21st@gmail.com>
// +----------------------------------------------------------------------

namespace Think;
/**
 * ThinkPHP 数据库中间层实现类
 */
class Db {

    static private  $instance   =  [];     //  数据库连接实例
    static private  $_instance  =  null;   //  当前数据库连接实例

    /**
     * 取得数据库类实例
     * @static
     * @access public
     * @param mixed $config 连接配置
     * @param boolean $lite 是否lite方式
     * @return Object 返回数据库驱动类
     */
    static public function instance($config=[],$lite=false) {
        $md5    =   md5(serialize($config));
        if(!isset(self::$instance[$md5])) {
            // 解析连接参数 支持数组和字符串
            $options    =   self::parseConfig($config);
            // 如果采用lite方式 仅支持原生SQL 包括query和execute方法
            $class  =   $lite?  'Think\Db\Lite' :   'Think\\Db\\Driver\\'.ucwords($options['dbms']);
            self::$instance[$md5]   =   new $class($options);
        }
        self::$_instance    =   self::$instance[$md5];
        return self::$_instance;
    }

    /**
     * 数据库连接参数解析
     * @static
     * @access public
     * @param mixed $config
     * @return array
     */
    static public function parseConfig($config){
        if(empty($config)) {
            $config =   Config::get();
        }
        if(is_string($config)) {
            return self::parseDsn($config);
        }
        return    [
              'dbms'        =>  $config['db_type'],
              'dsn'         =>  $config['db_dsn'],
              'username'    =>  $config['db_user'],
              'password'    =>  $config['db_pwd'],
              'hostname'    =>  $config['db_host'],
              'hostport'    =>  $config['db_port'],
              'database'    =>  $config['db_name'],
              'params'      =>  $config['db_params'],
              'charset'     =>  $config['db_charset'],
              'deploy'      =>  $config['db_deploy'],
              'socket'      =>  $config['db_unix_socket'],
              'debug'       =>  $config['db_debug'],
              'deploy'      =>  $config['db_deploy'],
         ];
    }

    /**
     * DSN解析
     * 格式： mysql://username:passwd@localhost:3306/DbName?param1=val1&param2=val2#utf8
     * @static
     * @access public
     * @param string $dsnStr
     * @return array
     */
    static public function parseDsn($dsnStr) {
        if( empty($dsnStr) ){return false;}
        $info = parse_url($dsnStr);
        if(!$info) {
            return false;
        }
        $dsn = [
            'dbms'      =>  $info['scheme'],
            'username'  =>  isset($info['user']) ? $info['user'] : '',
            'password'  =>  isset($info['pass']) ? $info['pass'] : '',
            'hostname'  =>  isset($info['host']) ? $info['host'] : '',
            'hostport'  =>  isset($info['port']) ? $info['port'] : '',
            'database'  =>  isset($info['path']) ? substr($info['path'],1) : '',
            'charset'   =>  isset($info['fragment'])?$info['fragment']:'',
        ];
        $dsn['dsn'] =  ''; // 兼容配置信息数组
        if(isset($info['query'])) {
            parse_str($info['query'],$dsn['params']);
        }else{
            $dsn['params']  =   [];
        }
        return $dsn;
     }

    // 调用驱动类的方法
	static public function __callStatic($method, $params){
		return call_user_func_array(array(self::$_instance, $method), $params);
	}
}