add set layout api

backend/app/Http/Controllers/SetController.php

@@ -2,7 +2,10 @@
 
 namespace App\Http\Controllers;
 
+use App\Exceptions\NotFoundException;
 use App\Set\Set;
+use App\Set\UseCases\GetSetLayout\ElementLayoutNode;
+use App\Set\UseCases\GetSetLayout\GetSetLayout;
 use App\Set\UseCases\ListSets\ListSets;
 use Illuminate\Http\JsonResponse;
 
@@ -10,6 +13,7 @@ class SetController extends Controller
 {
     public function __construct(
         private ListSets $listSets,
+        private GetSetLayout $getSetLayout,
     ) {}
 
     public function index(): JsonResponse
@@ -23,4 +27,52 @@ class SetController extends Controller
 
         return new JsonResponse(['sets' => $sets]);
     }
+
+    public function show(int $setId): JsonResponse
+    {
+        try {
+            $layout = $this->getSetLayout->execute($setId);
+        } catch (NotFoundException $exception) {
+            return new JsonResponse(
+                ['error' => $exception->getMessage()],
+                404,
+            );
+        }
+
+        $set = $layout->getSet();
+
+        return new JsonResponse([
+            'set' => [
+                'id' => $set->getId(),
+                'name' => $set->getName(),
+            ],
+            'elements' => array_map(
+                $this->elementPayload(...),
+                $layout->getElements(),
+            ),
+        ]);
+    }
+
+    /**
+     * @return array{
+     *     id: int,
+     *     name: string,
+     *     kind: string,
+     *     children: list<mixed>
+     * }
+     */
+    private function elementPayload(ElementLayoutNode $node): array
+    {
+        $element = $node->getElement();
+
+        return [
+            'id' => $element->getId(),
+            'name' => $element->getName(),
+            'kind' => $element->getKind(),
+            'children' => array_map(
+                $this->elementPayload(...),
+                $node->getChildren(),
+            ),
+        ];
+    }
 }