class SystemEmailToUsersOfRole

class SystemEmailToUsersOfRole extends RulesActionBase implements ContainerFactoryPluginInterface {
    
    /**
     * @var \Drupal\Core\Logger\LoggerChannelInterface
     */
    protected $logger;
    
    /**
     * @var \Drupal\Core\Mail\MailManagerInterface
     */
    protected $mailManager;
    
    /**
     * @var \Drupal\user\UserStorageInterface
     */
    protected $userStorage;
    
    /**
     * Constructs a SystemEmailToUsersOfRole 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\Logger\LoggerChannelInterface $logger
     *   The rules logger service.
     * @param \Drupal\Core\Mail\MailManagerInterface $mail_manager
     *   The mail manager service.
     * @param \Drupal\user\UserStorageInterface $userStorage
     *   The user storage service.
     */
    public function __construct(array $configuration, $plugin_id, $plugin_definition, LoggerChannelInterface $logger, MailManagerInterface $mail_manager, UserStorageInterface $userStorage) {
        parent::__construct($configuration, $plugin_id, $plugin_definition);
        $this->logger = $logger;
        $this->mailManager = $mail_manager;
        $this->userStorage = $userStorage;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
        return new static($configuration, $plugin_id, $plugin_definition, $container->get('logger.factory')
            ->get('rules'), $container->get('plugin.manager.mail'), $container->get('entity_type.manager')
            ->getStorage('user'));
    }
    
    /**
     * Sends an email to all users of the specified role(s).
     *
     * @param \Drupal\user\RoleInterface[] $roles
     *   Array of user roles.
     * @param string $subject
     *   Subject of the email.
     * @param string $message
     *   Email message text.
     * @param string $reply
     *   (optional) Reply to email address.
     * @param \Drupal\Core\Language\LanguageInterface $language
     *   (optional) Language object. If not specified, email will be sent to each
     *   recipient in the recipient's preferred language.
     */
    protected function doExecute(array $roles, $subject, $message, $reply = NULL, LanguageInterface $language = NULL) {
        if (empty($roles)) {
            return;
        }
        $rids = array_map(function ($role) {
            return $role->id();
        }, $roles);
        // Set a unique key for this email.
        $key = 'rules_action_mail_' . $this->getPluginId();
        // Select only active users, based on the roles given. We do not want to
        // send email to blocked users.
        $accounts = $this->userStorage
            ->loadByProperties([
            'roles' => $rids,
            'status' => 1,
        ]);
        $params = [
            'subject' => $subject,
            'message' => $message,
        ];
        // Loop over users and send email to each individually using that user's
        // preferred language (or a fixed language, if passed in the context).
        $number = 0;
        foreach ($accounts as $account) {
            // Language to use. Value passed in the context takes precedence.
            // ORIG.
            $langcode = isset($language) ? $language->getId() : $account->getPreferredLangcode();
            // @todo Is this better?
            $langcode = isset($language) && $language->getId() != LanguageInterface::LANGCODE_NOT_SPECIFIED ? $language->getId() : $account->getPreferredLangcode();
            $message = $this->mailManager
                ->mail('rules', $key, $account->getEmail(), $langcode, $params, NULL);
            $number += $message['result'] ? 1 : 0;
        }
        $this->logger
            ->notice('Successfully sent email to %number out of %count users having the role(s) %roles', [
            '%number' => $number,
            '%count' => count($accounts),
            '%roles' => implode(', ', $rids),
        ]);
    }

}