#4 console command to get registered subscriber notifications

src/Command/SubscriberNotificationsCommand.php

@@ -0,0 +1,39 @@
+<?php
+
+namespace App\Command;
+
+use App\Subscriber\Notification\NotificationHandlerCollection;
+use Symfony\Component\Console\Attribute\AsCommand;
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+use Symfony\Component\Console\Style\SymfonyStyle;
+
+#[AsCommand(
+    name: 'subscriber:notifications',
+    description: 'Show a list of registered subscriber notification types',
+)]
+final class SubscriberNotificationsCommand extends Command
+{
+    public function __construct(
+        private readonly NotificationHandlerCollection $handlerCollection,
+    ) {
+        parent::__construct();
+    }
+
+    protected function execute(InputInterface $input, OutputInterface $output): int
+    {
+        $io = new SymfonyStyle($input, $output);
+
+        $handlerTypes = $this->handlerCollection->getHandlerTypes();
+
+        if ($handlerTypes) {
+            $io->title('Notification handlers:');
+            $io->block($handlerTypes);
+        } else {
+            $io->warning('No subscriber notification handlers found.');
+        }
+
+        return Command::SUCCESS;
+    }
+}