Access Database in Core class

I'm trying to make a site multilanguage.
We use diffent .json files with the translation of every term according to de language wich can be the set in a cookie or can be the default language.

I changed .htaccess file so when we get something like http://siteurl/en/controller/action it would rewrite to http://siteurl/controller/action?__lang=en, this works perfectly

The problem appeared when i had to set the new base_url, because the available languages can be eddited by an administrator, krogerfeedback so I proceed to create a new controller in the application/core folder in wich i changed the base_url with the cookie value or the default language

But i had to use a mysqli object, write user and password again, and I didnt like that but I cant use the DB because core classes instances are created long before $CI is created so no "instance" is available for &get_instance().

Any help or idea to make this cleaner?

Heres my code:

PHP Code:

class MY_Config extends CI_Config {

    public function __construct() {

        $this->config =& get_config();
        $language_code = '';
        if(isset($_COOKIE['language']))
        {
            $conn = new mysqli("localhost","root","root","test");
            $stmt = $conn->prepare("select * from language l where l.code = ?");
            $stmt->bind_param("s", $code);
            $code = $_COOKIE['language'];
            $stmt->execute();
            $result = $stmt->get_result();
            
            if($result->num_rows == 1)
                $language_code = $_COOKIE['language'];
        }
        
        if($language_code == '')
        {
            $conn = new mysqli("localhost","root","root","test");
            $stmt = $conn->prepare("select s.value from settings s where s.key = ?");
            $stmt->bind_param("s", $lang);
            $lang = 'language';
            $stmt->execute();
            $result = $stmt->get_result();
            if($result->num_rows == 1)
                $language_code = $result->fetch_assoc()['value'];
        }

        if($language_code != '')        
            $this->set_item('base_url', $this->config['base_url'] . $language_code . '/');
    }
} 


I have also faced same issue. Did you really find solution??