class RegisterForm

class RegisterForm extends AccountForm {
  
  /**
   * {@inheritdoc}
   */
  public function form(array $form, FormStateInterface $form_state) {
    $user = $this->currentUser();
    /** @var \Drupal\user\UserInterface $account */
    $account = $this->entity;
    // This form is used for two cases:
    // - Self-register (route = 'user.register').
    // - Admin-create (route = 'user.admin_create').
    // If the current user has permission to create users then it must be the
    // second case.
    $admin = $account->access('create');
    // Pass access information to the submit handler. Running an access check
    // inside the submit function interferes with form processing and breaks
    // hook_form_alter().
    $form['administer_users'] = [
      '#type' => 'value',
      '#value' => $admin,
    ];
    $form['#attached']['library'][] = 'core/drupal.form';
    // For non-admin users, populate the form fields using data from the
    // browser.
    if (!$admin) {
      $form['#attributes']['data-user-info-from-browser'] = TRUE;
    }
    // Because the user status has security implications, users are blocked by
    // default when created programmatically and need to be actively activated
    // if needed. When administrators create users from the user interface,
    // however, we assume that they should be created as activated by default.
    if ($admin) {
      $account->activate();
    }
    // Start with the default user account fields.
    $form = parent::form($form, $form_state, $account);
    return $form;
  }
  
  /**
   * {@inheritdoc}
   */
  protected function actions(array $form, FormStateInterface $form_state) {
    $element = parent::actions($form, $form_state);
    $element['submit']['#value'] = $this->t('Create new account');
    return $element;
  }
  
  /**
   * {@inheritdoc}
   */
  public function submitForm(array &$form, FormStateInterface $form_state) {
    $admin = $form_state->getValue('administer_users');
    if (!\Drupal::config('user.settings')->get('verify_mail') || $admin) {
      $pass = $form_state->getValue('pass');
    }
    else {
      $pass = user_password();
    }
    // Remove unneeded values.
    $form_state->cleanValues();
    $form_state->setValue('pass', $pass);
    $form_state->setValue('init', $form_state->getValue('mail'));
    parent::submitForm($form, $form_state);
  }
  
  /**
   * {@inheritdoc}
   */
  public function save(array $form, FormStateInterface $form_state) {
    $account = $this->entity;
    $pass = $account->getPassword();
    $admin = $form_state->getValue('administer_users');
    $notify = !$form_state->isValueEmpty('notify');
    // Save has no return value so this cannot be tested.
    // Assume save has gone through correctly.
    $account->save();
    $form_state->set('user', $account);
    $form_state->setValue('uid', $account->id());
    $this->logger('user')
      ->notice('New user: %name %email.', [
      '%name' => $form_state->getValue('name'),
      '%email' => '<' . $form_state->getValue('mail') . '>',
      'type' => $account->toLink($this->t('Edit'), 'edit-form')
        ->toString(),
    ]);
    // Add plain text password into user account to generate mail tokens.
    $account->password = $pass;
    // New administrative account without notification.
    if ($admin && !$notify) {
      $this->messenger()
        ->addStatus($this->t('Created a new user account for <a href=":url">%name</a>. No email has been sent.', [
        ':url' => $account->toUrl()
          ->toString(),
        '%name' => $account->getAccountName(),
      ]));
    }
    elseif (!$admin && !\Drupal::config('user.settings')->get('verify_mail') && $account->isActive()) {
      _user_mail_notify('register_no_approval_required', $account);
      user_login_finalize($account);
      $this->messenger()
        ->addStatus($this->t('Registration successful. You are now logged in.'));
      $form_state->setRedirect('<front>');
    }
    elseif ($account->isActive() || $notify) {
      if (!$account->getEmail() && $notify) {
        $this->messenger()
          ->addStatus($this->t('The new user <a href=":url">%name</a> was created without an email address, so no welcome message was sent.', [
          ':url' => $account->toUrl()
            ->toString(),
          '%name' => $account->getAccountName(),
        ]));
      }
      else {
        $op = $notify ? 'register_admin_created' : 'register_no_approval_required';
        if (_user_mail_notify($op, $account)) {
          if ($notify) {
            $this->messenger()
              ->addStatus($this->t('A welcome message with further instructions has been emailed to the new user <a href=":url">%name</a>.', [
              ':url' => $account->toUrl()
                ->toString(),
              '%name' => $account->getAccountName(),
            ]));
          }
          else {
            $this->messenger()
              ->addStatus($this->t('A welcome message with further instructions has been sent to your email address.'));
            $form_state->setRedirect('<front>');
          }
        }
      }
    }
    else {
      _user_mail_notify('register_pending_approval', $account);
      $this->messenger()
        ->addStatus($this->t('Thank you for applying for an account. Your account is currently pending approval by the site administrator.<br />In the meantime, a welcome message with further instructions has been sent to your email address.'));
      $form_state->setRedirect('<front>');
    }
  }

}