feat: GetManga endpoint + tests

src/Domain/Manga/Application/QueryHandler/GetMangaHandler.php

@@ -0,0 +1,38 @@
+<?php
+
+namespace App\Domain\Manga\Application\QueryHandler;
+
+use App\Domain\Manga\Application\Query\GetManga;
+use App\Domain\Manga\Application\Response\MangaResponse;
+use App\Domain\Manga\Domain\Contract\Repository\MangaRepositoryInterface;
+use App\Domain\Manga\Domain\Exception\MangaNotFoundException;
+
+readonly class GetMangaHandler
+{
+    public function __construct(
+        private MangaRepositoryInterface $mangaRepository
+    ) {}
+
+    public function handle(GetManga $query): MangaResponse
+    {
+        $manga = $this->mangaRepository->findById($query->id);
+
+        if (!$manga) {
+            throw new MangaNotFoundException();
+        }
+
+        return new MangaResponse(
+            id: $manga->getId()->getValue(),
+            title: $manga->getTitle()->getValue(),
+            slug: $manga->getSlug()->getValue(),
+            description: $manga->getDescription(),
+            author: $manga->getAuthor(),
+            publicationYear: $manga->getPublicationYear(),
+            genres: $manga->getGenres(),
+            status: $manga->getStatus(),
+            externalId: $manga->getExternalId()?->getValue(),
+            imageUrl: $manga->getImageUrl(),
+            rating: $manga->getRating()
+        );
+    }
+}