Issue #3029161 by dench0, majid.ali, B-Prod: Port the module to D8

 * @return mixed

 */

function recaptcha_v3_pre_captcha_element_process(&$element, FormStateInterface $form_state, &$complete_form) {

  // Some alterations needed only if:

  // form was submitted or performed form API ajax request.

  // If form is processed input then recaptcha v3 response should be in

  // form values and need replace reCAPTCHA v3 element by fallback

  // challenge before captcha module lement process callback, because otherwise

  // in case of error form will not rebuild and recaptcha v3 element will

  // return again.

  if ($form_state->isProcessingInput()) {

    \Drupal::moduleHandler()->loadInclude('captcha', 'module', 'inc');

    \Drupal::moduleHandler()->loadInclude('captcha', 'inc', 'captcha');

    [$captcha_type_module, $captcha_type_challenge] = _captcha_parse_captcha_type($element['#captcha_type']);

    if ($captcha_type_module !== 'recaptcha_v3') {

      return $element;

    }

    // If form_state storage has already verification response,

    // then replace reCAPTCHA v3 captcha by action fallback challenge.

    // If form is submitted and this is not ajax request, then need to replace

    // reCAPTCHA v3 element by fallback challenge because otherwise in case of

    // error form will not rebuild and recaptcha v3 element will return again.

    $is_ajax_request = \Drupal::request()->query->has(FormBuilderInterface::AJAX_FORM_REQUEST);

    if (!$is_ajax_request || $form_state->has('recaptcha_v3')) {

    if ($captcha_type_module === 'recaptcha_v3') {

      $action = ReCaptchaV3Action::load($captcha_type_challenge);

      $challenge = $action ? $action->getChallenge() : 'default';

      // Replacing 'default' challenge by the real captcha challenge.

      $captcha = [];

      if ($recaptcha_v3_action = ReCaptchaV3Action::load($captcha_type)) {

        $config = \Drupal::config('recaptcha_v3.settings');

        $action_name = $recaptcha_v3_action->id();

        $captcha['form']['captcha_response'] = [

          '#type' => 'hidden',

          '#default_value' => '',

            // to attaching event for triggering ajax request,

            'id' => Html::getUniqueId('recaptcha_v3_token'),

            'class' => ['recaptcha-v3-token'],

            'data-recaptcha-v3-action' => $action_name,

            'data-recaptcha-v3-action' => $recaptcha_v3_action->id(),

            'data-recaptcha-v3-site-key' => $config->get('site_key'),

          ],

          '#attached' => [

 * @param $element

 * @param \Drupal\Core\Form\FormStateInterface $form_state

 * @param $complete_form

 *

 * @return array

 */

function recaptcha_v3_post_captcha_element_process(&$element, FormStateInterface $form_state, &$complete_form) {

  if ($form_state->getTemporaryValue('recaptcha_v3_action_name') && !$form_state->has('recaptcha_v3')) {

    ]);

  $verification_response = _recaptcha_v3_verify_captcha_response($recaptcha_v3, $captcha_response);

  // If we here, then token verification failed.

  if (!$verification_response['success']) {

    // If we here, then token verification failed.

    if($verification_response['error-codes']) {

      $errors = [];

      foreach ($verification_response['error-codes'] as $code) {

        $errors[] = recaptcha_v3_error_by_code($code);

      }

      $errors_string = implode(" ", $errors);

      $errors_string = implode(' ', $errors);

      \Drupal::logger('recaptcha_v3')->error('Google reCAPTCHA v3 validation failed: @error', ['@error' => $errors_string]);

    }

    $error_message = \Drupal::config('recaptcha_v3.settings')

      ->get('error_message');

    $form_state->setError($element, $error_message);

  }

  // Save captcha response in $form_state storage to prevent

  // further validation requests.

  $form_state->set('recaptcha_v3', $verification_response);

  // Need to cache form, because previous line does not make sense

  // because form will not cached otherwise. Probably this is wrong because

  // if form set for rebuilding it will not cached anyway.

  // @todo need to check if need to move next line to the element preprocess callback.

  $form_state->setCached();

  return (bool) $verification_response['success'];

}

 * Error code reference, https://developers.google.com/recaptcha/docs/verify

 * @param $code

 *

 * @return mixed

 * @return \Drupal\Core\StringTranslation\TranslatableMarkup

 */

function recaptcha_v3_error_by_code($code) {

  $error_codes = &drupal_static(__FUNCTION__);

  if (!isset($error_codes)) {

    $error_codes = [

      'timeout-or-duplicate' => t('The response is no longer valid: either is too old or has been used previously.'),

      'bad-request' => t('The request is invalid or malformed.'),

      'score-threshold-not-met' => t('Score threshold not met.'),

      'unknown-error' => t('Not a success, but no error codes received!'),

    ];

  }

  return $error_codes[$code] ?? $error_codes['unknown-error'];

}