postoffice-1.0.x-dev/src/MailerMiddleware/Theme.php

<?php

namespace Drupal\postoffice\MailerMiddleware;

use Drupal\Core\Config\ConfigFactoryInterface;
use Drupal\Core\Theme\ThemeInitializationInterface;
use Drupal\Core\Theme\ThemeManagerInterface;
use Symfony\Component\Mailer\Envelope;
use Symfony\Component\Mailer\MailerInterface;
use Symfony\Component\Mime\RawMessage;

/**
 * Implements the theme mailer middleware.
 */
class Theme implements MailerInterface {

  /**
   * The decorated mailer.
   */
  protected MailerInterface $mailer;

  /**
   * The theme manager.
   */
  protected ThemeManagerInterface $themeManager;

  /**
   * The theme initialization service.
   */
  protected ThemeInitializationInterface $themeInitialization;

  /**
   * Config factory.
   */
  protected ConfigFactoryInterface $configFactory;

  /**
   * Constructs a new language mailer middleware.
   */
  public function __construct(
    MailerInterface $mailer,
    ThemeManagerInterface $themeManager,
    ThemeInitializationInterface $themeInitialization,
    ConfigFactoryInterface $configFactory,
  ) {
    $this->mailer = $mailer;
    $this->themeManager = $themeManager;
    $this->themeInitialization = $themeInitialization;
    $this->configFactory = $configFactory;
  }

  /**
   * {@inheritdoc}
   */
  public function send(RawMessage $message, ?Envelope $envelope = NULL): void {
    $originalTheme = $this->themeManager->getActiveTheme()->getName();
    $mailTheme = $this->getMailTheme($message);

    try {
      if ($originalTheme !== $mailTheme) {
        $this->themeManager->setActiveTheme($this->themeInitialization->initTheme($mailTheme));
      }
      $this->mailer->send($message, $envelope);
    }
    finally {
      $activeTheme = $this->themeManager->getActiveTheme()->getName();
      if ($activeTheme !== $originalTheme) {
        $this->themeManager->setActiveTheme($this->themeInitialization->initTheme($originalTheme));
      }
    }
  }

  /**
   * Determine the mail theme.
   */
  public function getMailTheme(RawMessage $message) {
    $result = $this->configFactory->get('system.theme')->get('default');

    $config = $this->configFactory->get('postoffice.site');
    if (!$config->get('theme_use_default')) {
      $result = $config->get('theme_name');
    }

    return $result;
  }

}