Add scene graph draft

Ghost.Editor.Core/SceneGraph/SceneNode.cs

@@ -1,50 +1,154 @@
-using System.Collections.ObjectModel;
+using Ghost.Engine.Core;
 using Ghost.Entities;
+using System.Collections.ObjectModel;
 
 namespace Ghost.Editor.Core.SceneGraph;
 
 /// <summary>
-/// Represents a Scene node in the editor hierarchy.
-/// Contains editor-only metadata like name and display state.
-/// The actual scene data (entities, components) is stored as SceneID in the runtime ECS world.
+/// Represents a scene node in the editor scene graph hierarchy.
+/// Contains editor-only metadata like display name and root entities.
 /// </summary>
 public class SceneNode
 {
-    public string Name { get; set; }
-    public short SceneId { get; private set; }
-    public Guid SceneGuid { get; private set; }
-    
-    /// <summary>
-    /// Child entity nodes belonging to this scene.
-    /// </summary>
-    public ObservableCollection<EntityNode> Children { get; }
+    private string _name;
+    private readonly ObservableCollection<EntityNode> _rootEntities;
 
-    public SceneNode(string name, short sceneId, Guid? sceneGuid = null)
+    /// <summary>
+    /// Gets or sets the runtime scene this node represents.
+    /// </summary>
+    public Scene Scene { get; set; }
+
+    /// <summary>
+    /// Gets or sets the display name for this scene in the editor.
+    /// This is NOT stored in runtime data.
+    /// </summary>
+    public string Name
     {
-        Name = name;
-        SceneId = sceneId;
-        SceneGuid = sceneGuid ?? Guid.NewGuid();
-        Children = new ObservableCollection<EntityNode>();
+        get => _name;
+        set
+        {
+            _name = value;
+            OnNameChanged?.Invoke(this);
+        }
     }
 
     /// <summary>
-    /// Finds an entity node by its global entity ID.
-    /// Searches recursively through the hierarchy.
+    /// Gets or sets the file path where this scene is saved.
     /// </summary>
-    public EntityNode? FindEntityNode(Entity entityId)
-    {
-        foreach (var child in Children)
-        {
-            if (child.EntityId == entityId)
-                return child;
+    public string? FilePath { get; set; }
 
-            var found = child.FindRecursive(entityId);
+    /// <summary>
+    /// Gets or sets whether this scene is currently loaded in the editor.
+    /// </summary>
+    public bool IsLoaded { get; set; }
+
+    /// <summary>
+    /// Gets or sets whether this scene has unsaved changes.
+    /// </summary>
+    public bool IsDirty { get; set; }
+
+    /// <summary>
+    /// Gets the collection of root entity nodes in this scene.
+    /// </summary>
+    public ObservableCollection<EntityNode> RootEntities => _rootEntities;
+
+    /// <summary>
+    /// Event raised when the name property changes.
+    /// </summary>
+    public event Action<SceneNode>? OnNameChanged;
+
+    /// <summary>
+    /// Event raised when root entities collection changes.
+    /// </summary>
+    public event Action<SceneNode>? OnRootEntitiesChanged;
+
+    public SceneNode(Scene scene, string name = "New Scene")
+    {
+        Scene = scene;
+        _name = name;
+        _rootEntities = [];
+        _rootEntities.CollectionChanged += (s, e) => OnRootEntitiesChanged?.Invoke(this);
+    }
+
+    /// <summary>
+    /// Adds a root entity node to this scene.
+    /// </summary>
+    /// <param name="entityNode">The entity node to add.</param>
+    public void AddRootEntity(EntityNode entityNode)
+    {
+        // Remove from previous parent if any
+        if (entityNode.Parent != null)
+        {
+            entityNode.Parent.RemoveChild(entityNode);
+        }
+
+        entityNode.Parent = null;
+        entityNode.OwnerScene = this;
+        _rootEntities.Add(entityNode);
+    }
+
+    /// <summary>
+    /// Removes a root entity node from this scene.
+    /// </summary>
+    /// <param name="entityNode">The entity node to remove.</param>
+    /// <returns>True if the entity was removed, false otherwise.</returns>
+    public bool RemoveRootEntity(EntityNode entityNode)
+    {
+        if (_rootEntities.Remove(entityNode))
+        {
+            entityNode.OwnerScene = null;
+            return true;
+        }
+
+        return false;
+    }
+
+    /// <summary>
+    /// Gets all entity nodes in this scene (root and descendants) in depth-first order.
+    /// </summary>
+    /// <returns>An enumerable of all entity nodes in the scene.</returns>
+    public IEnumerable<EntityNode> GetAllEntities()
+    {
+        foreach (var root in _rootEntities)
+        {
+            yield return root;
+
+            foreach (var descendant in root.GetAllDescendants())
+            {
+                yield return descendant;
+            }
+        }
+    }
+
+    /// <summary>
+    /// Finds an entity node by its entity reference.
+    /// </summary>
+    /// <param name="entity">The entity to search for.</param>
+    /// <returns>The entity node if found, null otherwise.</returns>
+    public EntityNode? FindNode(Entity entity)
+    {
+        foreach (var root in _rootEntities)
+        {
+            var found = root.FindNode(entity);
             if (found != null)
+            {
                 return found;
+            }
         }
 
         return null;
     }
 
-    public override string ToString() => $"Scene: {Name} (ID: {SceneId})";
+    /// <summary>
+    /// Marks this scene as dirty (has unsaved changes).
+    /// </summary>
+    public void MarkDirty()
+    {
+        IsDirty = true;
+    }
+
+    public override string ToString()
+    {
+        return $"{Name} (Scene ID: {Scene.ID}, Entities: {_rootEntities.Count})";
+    }
 }