membuat rest api login akun google menggunakan ci

permisi apa ada yang bisa bantu untuk membuat rest api dari kodingan di bawah, tugas nya harus rubah kodingan di bawah jadi rest api??????????????

 public function create_google(){
        // Include the google api php libraries
        include_once APPPATH."libraries/google-api-php-client/Google_Client.php";
        include_once APPPATH."libraries/google-api-php-client/contrib/Google_Oauth2Service.php";

        // Google Project API Credentials
        $clientId = 'Insert Google Client ID';
        $clientSecret = 'Insert Google Client secret';
        $redirectUrl = base_url() . 'user_authentication/';

        // Google Client Configuration
        $gClient = new Google_Client();
        $gClient->setApplicationName('Login to codexworld.com');
        $gClient->setClientId($clientId);
        $gClient->setClientSecret($clientSecret);
        $gClient->setRedirectUri($redirectUrl);
        $google_oauthV2 = new Google_Oauth2Service($gClient);

        if (isset($_REQUEST['code'])) {
            $gClient->authenticate();
            $this->session->set_userdata('token', $gClient->getAccessToken());
            redirect($redirectUrl);
        }

        $token = $this->session->userdata('token');
        if (!empty($token)) {
            $gClient->setAccessToken($token);
        }

        if ($gClient->getAccessToken()) {
            $userProfile = $google_oauthV2->userinfo->get();
            // Preparing data for database insertion
            $userData['oauth_provider'] = 'google';
            $userData['oauth_uid'] = $userProfile['id'];
            $userData['first_name'] = $userProfile['given_name'];
            $userData['last_name'] = $userProfile['family_name'];
            $userData['email'] = $userProfile['email'];
            $userData['gender'] = $userProfile['gender'];
            $userData['locale'] = $userProfile['locale'];
            $userData['profile_url'] = $userProfile['link'];
            $userData['picture_url'] = $userProfile['picture'];
            // Insert or update user data
            $userID = $this->user->checkUser($userData);
            if(!empty($userID)){
                $data['userData'] = $userData;
                $this->session->set_userdata('userData',$userData);
            } else {
               $data['userData'] = array();
            }
        } else {
            $data['authUrl'] = $gClient->createAuthUrl();
        }
        $this->load->view('user_authentication/index',$data);
    }