class RegisterForm

class RegisterForm extends AccountForm {
    
    /**
     * {@inheritdoc}
     */
    public function form(array $form, FormStateInterface $form_state) {
        
        /** @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);
        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 = \Drupal::service('password_generator')->generate();
        }
        // 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')
            ->info('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>');
        }
    }

}