class EmailAction

class EmailAction extends ConfigurableActionBase implements ContainerFactoryPluginInterface {
  
  /**
   * The token service.
   *
   * @var \Drupal\Core\Utility\Token
   */
  protected $token;
  
  /**
   * The user storage.
   *
   * @var \Drupal\Core\Entity\EntityStorageInterface
   */
  protected $storage;
  
  /**
   * A logger instance.
   *
   * @var \Psr\Log\LoggerInterface
   */
  protected $logger;
  
  /**
   * The mail manager.
   *
   * @var \Drupal\Core\Mail\MailManagerInterface
   */
  protected $mailManager;
  
  /**
   * The language manager.
   *
   * @var \Drupal\Core\Language\LanguageManagerInterface
   */
  protected $languageManager;
  
  /**
   * The email validator.
   *
   * @var \Drupal\Component\Utility\EmailValidatorInterface
   */
  protected $emailValidator;
  
  /**
   * Constructs an EmailAction object.
   *
   * @param array $configuration
   *   A configuration array containing information about the plugin instance.
   * @param string $plugin_id
   *   The plugin ID for the plugin instance.
   * @param mixed $plugin_definition
   *   The plugin implementation definition.
   * @param \Drupal\Core\Utility\Token $token
   *   The token service.
   * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
   *   The entity type manager.
   * @param \Psr\Log\LoggerInterface $logger
   *   A logger instance.
   * @param \Drupal\Core\Mail\MailManagerInterface $mail_manager
   *   The mail manager.
   * @param \Drupal\Core\Language\LanguageManagerInterface $language_manager
   *   The language manager.
   * @param \Drupal\Component\Utility\EmailValidatorInterface $email_validator
   *   The email validator.
   */
  public function __construct(array $configuration, $plugin_id, $plugin_definition, Token $token, EntityTypeManagerInterface $entity_type_manager, LoggerInterface $logger, MailManagerInterface $mail_manager, LanguageManagerInterface $language_manager, EmailValidatorInterface $email_validator) {
    parent::__construct($configuration, $plugin_id, $plugin_definition);
    $this->token = $token;
    $this->storage = $entity_type_manager->getStorage('user');
    $this->logger = $logger;
    $this->mailManager = $mail_manager;
    $this->languageManager = $language_manager;
    $this->emailValidator = $email_validator;
  }
  
  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
    return new static($configuration, $plugin_id, $plugin_definition, $container->get('token'), $container->get('entity_type.manager'), $container->get('logger.factory')
      ->get('action'), $container->get('plugin.manager.mail'), $container->get('language_manager'), $container->get('email.validator'));
  }
  
  /**
   * {@inheritdoc}
   */
  public function execute($entity = NULL) {
    if (empty($this->configuration['node'])) {
      $this->configuration['node'] = $entity;
    }
    $recipient = PlainTextOutput::renderFromHtml($this->token
      ->replace($this->configuration['recipient'], $this->configuration));
    // If the recipient is a registered user with a language preference, use
    // the recipient's preferred language. Otherwise, use the system default
    // language.
    $recipient_accounts = $this->storage
      ->loadByProperties([
      'mail' => $recipient,
    ]);
    $recipient_account = reset($recipient_accounts);
    if ($recipient_account) {
      $langcode = $recipient_account->getPreferredLangcode();
    }
    else {
      $langcode = $this->languageManager
        ->getDefaultLanguage()
        ->getId();
    }
    $params = [
      'context' => $this->configuration,
    ];
    $message = $this->mailManager
      ->mail('system', 'action_send_email', $recipient, $langcode, $params);
    // Error logging is handled by \Drupal\Core\Mail\MailManager::mail().
    if ($message['result']) {
      $this->logger
        ->info('Sent email to %recipient', [
        '%recipient' => $recipient,
      ]);
    }
  }
  
  /**
   * {@inheritdoc}
   */
  public function defaultConfiguration() {
    return [
      'recipient' => '',
      'subject' => '',
      'message' => '',
    ];
  }
  
  /**
   * {@inheritdoc}
   */
  public function buildConfigurationForm(array $form, FormStateInterface $form_state) {
    $form['recipient'] = [
      '#type' => 'textfield',
      '#title' => $this->t('Recipient email address'),
      '#default_value' => $this->configuration['recipient'],
      '#maxlength' => '254',
      '#description' => $this->t('You may also use tokens: [node:author:mail], [comment:author:mail], etc. Separate recipients with a comma.'),
    ];
    $form['subject'] = [
      '#type' => 'textfield',
      '#title' => $this->t('Subject'),
      '#default_value' => $this->configuration['subject'],
      '#maxlength' => '254',
      '#description' => $this->t('The subject of the message.'),
    ];
    $form['message'] = [
      '#type' => 'textarea',
      '#title' => $this->t('Message'),
      '#default_value' => $this->configuration['message'],
      '#cols' => '80',
      '#rows' => '20',
      '#description' => $this->t('The message that should be sent. You may include placeholders like [node:title], [user:account-name], [user:display-name] and [comment:body] to represent data that will be different each time message is sent. Not all placeholders will be available in all contexts.'),
    ];
    return $form;
  }
  
  /**
   * {@inheritdoc}
   */
  public function validateConfigurationForm(array &$form, FormStateInterface $form_state) {
    if (!$this->emailValidator
      ->isValid($form_state->getValue('recipient')) && !str_contains($form_state->getValue('recipient'), ':mail')) {
      // We want the literal %author placeholder to be emphasized in the error message.
      $form_state->setErrorByName('recipient', $this->t('Enter a valid email address or use a token email address such as %author.', [
        '%author' => '[node:author:mail]',
      ]));
    }
  }
  
  /**
   * {@inheritdoc}
   */
  public function submitConfigurationForm(array &$form, FormStateInterface $form_state) {
    $this->configuration['recipient'] = $form_state->getValue('recipient');
    $this->configuration['subject'] = $form_state->getValue('subject');
    $this->configuration['message'] = $form_state->getValue('message');
  }
  
  /**
   * {@inheritdoc}
   */
  public function access($object, ?AccountInterface $account = NULL, $return_as_object = FALSE) {
    $result = AccessResult::allowed();
    return $return_as_object ? $result : $result->isAllowed();
  }

}