feat: send mailings over MailJet smtp in dedicated worker process

src/Controller/Admin/Teamer/MailingController.php

@@ -5,6 +5,7 @@ namespace App\Controller\Admin\Teamer;
 use App\Controller\Traits\ReturnUrlTrait;
 use App\Form\TeamerMailingType;
 use App\Htmx\HxRedirectResponse;
+use App\Message\SendTeamerMailing;
 use App\Service\Common\TeamerFilterHandler;
 use App\Service\Teamer\TeamerMailingDraftHandler;
 use App\Service\Teamer\TeamerMailingService;
@@ -12,6 +13,7 @@ use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
 use Symfony\Component\Form\FormInterface;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\Messenger\MessageBusInterface;
 use Symfony\Component\Routing\Attribute\Route;
 use Symfony\Component\Security\Http\Attribute\IsGranted;
 
@@ -23,6 +25,7 @@ class MailingController extends AbstractController
         private readonly TeamerFilterHandler $filterHandler,
         private readonly TeamerMailingService $mailingService,
         private readonly TeamerMailingDraftHandler $draftHandler,
+        private readonly MessageBusInterface $messageBus,
     ) {
     }
 
@@ -114,12 +117,25 @@ class MailingController extends AbstractController
         }
 
         $recipients = $this->mailingService->resolveRecipients($this->filterHandler->getFilterSettings());
-        $count = $this->mailingService->send($form->getData(), $recipients);
+        $mailingDto = $form->getData();
 
-        // it went out, the next mailing starts on a blank page
+        // the recipients travel with the message, so the mailing reaches exactly the
+        // people the confirmation modal counted even though it is sent from a worker
+        $this->messageBus->dispatch(SendTeamerMailing::fromRecipients(
+            (string) $mailingDto->getSubject(),
+            (string) $mailingDto->getMessage(),
+            $recipients
+        ));
+
+        // it is on its way, the next mailing starts on a blank page
         $this->draftHandler->resetDraft();
 
-        $this->addFlash('success', sprintf('Die Mail wurde an %d Teamer:innen gesendet', $count));
+        // deliberately not "wurde gesendet": at this point nothing has been handed to a
+        // mail server yet, and saying otherwise would make a failed mailing look fine
+        $this->addFlash('success', sprintf(
+            'Die Mail wird an %d Teamer:innen gesendet',
+            $recipients->getEligibleCount()
+        ));
 
         return new HxRedirectResponse($this->generateUrl('app_administrative_teamer_index'));
     }