feat: BehaviourCacher<T>

Engine.Core/BehaviourCacher.cs

@@ -0,0 +1,79 @@
+using System;
+using System.Collections.Generic;
+
+using Syntriax.Engine.Core.Abstract;
+
+namespace Syntriax.Engine.Core;
+
+public class BehaviourCacher<T> : IAssignableGameManager where T : IBehaviour
+{
+    public Action<IAssignable>? OnUnassigned { get; set; } = null;
+    public Action<IAssignableGameManager>? OnGameManagerAssigned { get; set; } = null;
+
+    public Action<BehaviourCacher<T>, T>? OnCached { get; set; } = null;
+    public Action<BehaviourCacher<T>, T>? OnUncached { get; set; } = null;
+
+    private readonly List<T> _behaviours = new(32);
+
+    public IReadOnlyList<T> Behaviours => _behaviours;
+    public IGameManager GameManager { get; private set; } = null!;
+
+    public BehaviourCacher() { }
+    public BehaviourCacher(IGameManager gameManager) => Assign(gameManager);
+
+    private void OnGameObjectRegistered(GameManager manager, IGameObject gameObject)
+    {
+        gameObject.BehaviourController.OnBehaviourAdded += OnBehaviourAdded;
+        gameObject.BehaviourController.OnBehaviourRemoved += OnBehaviourRemoved;
+    }
+
+    private void OnGameObjectUnregistered(GameManager manager, IGameObject gameObject)
+    {
+        gameObject.BehaviourController.OnBehaviourAdded -= OnBehaviourAdded;
+        gameObject.BehaviourController.OnBehaviourRemoved -= OnBehaviourRemoved;
+    }
+
+    private void OnBehaviourAdded(IBehaviourController controller, IBehaviour behaviour)
+    {
+        if (behaviour is not T tBehaviour)
+            return;
+
+        _behaviours.Add(tBehaviour);
+        OnCached?.Invoke(this, tBehaviour);
+    }
+
+    private void OnBehaviourRemoved(IBehaviourController controller, IBehaviour behaviour)
+    {
+        if (behaviour is not T tBehaviour)
+            return;
+
+        if (!_behaviours.Remove(tBehaviour))
+            return;
+
+        OnUncached?.Invoke(this, tBehaviour);
+    }
+
+    public bool Assign(IGameManager gameManager)
+    {
+        if (GameManager is not null)
+            return false;
+
+        gameManager.OnGameObjectRegistered += OnGameObjectRegistered;
+        gameManager.OnGameObjectUnRegistered += OnGameObjectUnregistered;
+
+        GameManager = gameManager;
+        return true;
+    }
+
+    public bool Unassign()
+    {
+        if (GameManager is null)
+            return false;
+
+        GameManager.OnGameObjectRegistered -= OnGameObjectRegistered;
+        GameManager.OnGameObjectUnRegistered -= OnGameObjectUnregistered;
+
+        GameManager = null!;
+        return true;
+    }
+}