add parent node to node, fix type of null

app/Node/CreateNodeDto.php

@@ -9,5 +9,6 @@ class CreateNodeDto
     public function __construct(
         public Text $text,
         public string $title,
+        public ?Node $parentNode,
     ) {}
 }

app/Node/Node.php

@@ -7,10 +7,17 @@ use App\Text\Text;
 class Node
 {
     public function __construct(
+        private int $id,
         private string $title,
         private Text $text,
+        private ?Node $parentNode,
     ) {}
 
+    public function getId(): int
+    {
+        return $this->id;
+    }
+
     public function getTitle(): string
     {
         return $this->title;
@@ -20,4 +27,9 @@ class Node
     {
         return $this->text;
     }
+
+    public function getParentNode(): ?Node
+    {
+        return $this->parentNode;
+    }
 }

app/Node/UseCases/CreateNode.php

@@ -22,10 +22,19 @@ class CreateNode
         if ($text === null) {
             throw new DomainException("Text with id: $id doesnt exist");
         }
+        if ($request->parentNodeId === null) {
+            return $this->nodeRepo->create(new CreateNodeDto(
+                text: $text,
+                title: $request->title,
+                parentNode: null,
+            ));
+        }
+        $parentNode = $this->nodeRepo->find($request->parentNodeId);
 
         return $this->nodeRepo->create(new CreateNodeDto(
             text: $text,
             title: $request->title,
+            parentNode: $parentNode,
         ));
     }
 }

app/Node/UseCases/CreateNodeRequest.php

@@ -7,5 +7,6 @@ class CreateNodeRequest
     public function __construct(
         public int $textId,
         public string $title,
+        public ?int $parentNodeId,
     ) {}
 }