add ordered element queries

backend/app/Element/ElementRepository.php

@@ -2,6 +2,7 @@
 
 namespace App\Element;
 
+use App\Set\Set;
 use DomainException;
 
 interface ElementRepository
@@ -12,4 +13,14 @@ interface ElementRepository
     public function create(CreateElementDto $dto): Element;
 
     public function find(int $id): ?Element;
+
+    /**
+     * @return list<Element>
+     */
+    public function findTopLevelBySet(Set $set): array;
+
+    /**
+     * @return list<Element>
+     */
+    public function findByParentElement(Element $parentElement): array;
 }

backend/app/Element/EloquentElementRepository.php

@@ -45,6 +45,48 @@ class EloquentElementRepository implements ElementRepository
         return $model === null ? null : $this->toDomain($model);
     }
 
+    public function findTopLevelBySet(Set $set): array
+    {
+        $models = ElementModel::query()
+            ->where('set_id', $set->getId())
+            ->whereNull('parent_element_id')
+            ->orderBy('position')
+            ->orderBy('id')
+            ->get();
+        $elements = [];
+
+        foreach ($models as $model) {
+            $elements[] = $this->toDomainWithRelations(
+                model: $model,
+                set: $set,
+                parentElement: null,
+            );
+        }
+
+        return $elements;
+    }
+
+    public function findByParentElement(Element $parentElement): array
+    {
+        $models = ElementModel::query()
+            ->where('set_id', $parentElement->getSet()->getId())
+            ->where('parent_element_id', $parentElement->getId())
+            ->orderBy('position')
+            ->orderBy('id')
+            ->get();
+        $elements = [];
+
+        foreach ($models as $model) {
+            $elements[] = $this->toDomainWithRelations(
+                model: $model,
+                set: $parentElement->getSet(),
+                parentElement: $parentElement,
+            );
+        }
+
+        return $elements;
+    }
+
     /**
      * @throws DomainException
      */
@@ -94,6 +136,18 @@ class EloquentElementRepository implements ElementRepository
             }
         }
 
+        return $this->toDomainWithRelations(
+            model: $model,
+            set: $set,
+            parentElement: $parentElement,
+        );
+    }
+
+    private function toDomainWithRelations(
+        ElementModel $model,
+        Set $set,
+        ?Element $parentElement,
+    ): Element {
         return new Element(
             id: $model->id,
             name: $model->name,

backend/tests/Fakes/FakeElementRepository.php

@@ -5,6 +5,7 @@ namespace Tests\Fakes;
 use App\Element\CreateElementDto;
 use App\Element\Element;
 use App\Element\ElementRepository;
+use App\Set\Set;
 use DomainException;
 
 class FakeElementRepository implements ElementRepository
@@ -38,6 +39,34 @@ class FakeElementRepository implements ElementRepository
         return $element === null ? null : $this->copy($element);
     }
 
+    public function findTopLevelBySet(Set $set): array
+    {
+        $elements = array_filter(
+            $this->elements,
+            function (Element $element) use ($set): bool {
+                return $element->getSet()->getId() === $set->getId()
+                    && $element->getParentElement() === null;
+            },
+        );
+
+        return $this->orderedCopies($elements);
+    }
+
+    public function findByParentElement(Element $parentElement): array
+    {
+        $elements = array_filter(
+            $this->elements,
+            function (Element $element) use ($parentElement): bool {
+                return $element->getSet()->getId()
+                    === $parentElement->getSet()->getId()
+                    && $element->getParentElement()?->getId()
+                    === $parentElement->getId();
+            },
+        );
+
+        return $this->orderedCopies($elements);
+    }
+
     /**
      * @throws DomainException
      */
@@ -79,6 +108,27 @@ class FakeElementRepository implements ElementRepository
         return $maximumPosition + 1;
     }
 
+    /**
+     * @param array<int, Element> $elements
+     * @return list<Element>
+     */
+    private function orderedCopies(array $elements): array
+    {
+        usort($elements, function (Element $first, Element $second): int {
+            $positionComparison = $first->getPosition()
+                <=> $second->getPosition();
+            if ($positionComparison !== 0) {
+                return $positionComparison;
+            }
+
+            return $first->getId() <=> $second->getId();
+        });
+
+        return array_map(function (Element $element): Element {
+            return $this->copy($element);
+        }, $elements);
+    }
+
     private function copy(Element $element): Element
     {
         $parentElement = $element->getParentElement();