add set layout api

backend/app/Element/ElementRepository.php

@@ -14,6 +14,11 @@ interface ElementRepository
 
     public function find(int $id): ?Element;
 
+    /**
+     * @return list<Element>
+     */
+    public function findBySet(Set $set): array;
+
     /**
      * @return list<Element>
      */

backend/app/Element/EloquentElementRepository.php

@@ -45,6 +45,37 @@ class EloquentElementRepository implements ElementRepository
         return $model === null ? null : $this->toDomain($model);
     }
 
+    public function findBySet(Set $set): array
+    {
+        $models = ElementModel::query()
+            ->where('set_id', $set->getId())
+            ->orderBy('id')
+            ->get();
+        $elements = [];
+        $elementsById = [];
+
+        foreach ($models as $model) {
+            $parentElement = null;
+            if ($model->parent_element_id !== null) {
+                $parentElement = $elementsById[$model->parent_element_id]
+                    ?? null;
+                if ($parentElement === null) {
+                    throw new RuntimeException('element parent not found');
+                }
+            }
+
+            $element = $this->toDomainWithRelations(
+                model: $model,
+                set: $set,
+                parentElement: $parentElement,
+            );
+            $elements[] = $element;
+            $elementsById[$element->getId()] = $element;
+        }
+
+        return $elements;
+    }
+
     public function findTopLevelBySet(Set $set): array
     {
         $models = ElementModel::query()
@@ -160,10 +191,9 @@ class EloquentElementRepository implements ElementRepository
 
     private function findSet(int $id): Set
     {
-        foreach ($this->setRepository->all() as $set) {
-            if ($set->getId() === $id) {
-                return $set;
-            }
+        $set = $this->setRepository->find($id);
+        if ($set !== null) {
+            return $set;
         }
 
         throw new RuntimeException('element set not found');