public function authentication()
    {
        $response = \Aperdia\Clef::authentication($_GET['code']);

        // error
        if (!$response) {
            $error = 'Error';
        // error
        } elseif (isset($response['error'])) {
            $error = $response['error'];
        // success
        } elseif (isset($response['success'])) {
            // verif if exists account in Authentication table
            $verif = Authentication::whereprovider("clef")->whereprovider_uid($response['info']['id'])->first();

            // no account
            if (empty($verif)) {


            // Find account
            } else {
                // Find the user using the user id
                $user = User::find($verif->user_id);

                // RAZ logout
                if ($user->logout == 1) {
                    $user->logout = 0;
                    $user->save();
                }

                // Log the user in
                Auth::login($user);

                return Redirect::intended('/');
            }
        // error
        } else {
            $error = 'Unknown error';
        }

        return Redirect::to("login")->withErrors($error);
    }