From d4c6288b38cc838d2c4217c079f59ec228854a52 Mon Sep 17 00:00:00 2001
From: Syntriax <Syntriax@gmail.com>
Date: Tue, 1 Apr 2025 12:19:58 +0300
Subject: [PATCH] feat: added behaviour collector for active behaviours only

---
 Engine.Core/ActiveBehaviourCollector.cs       | 123 ++++++++++++++++++
 Engine.Core/ActiveBehaviourCollectorSorted.cs |  19 +++
 2 files changed, 142 insertions(+)
 create mode 100644 Engine.Core/ActiveBehaviourCollector.cs
 create mode 100644 Engine.Core/ActiveBehaviourCollectorSorted.cs

diff --git a/Engine.Core/ActiveBehaviourCollector.cs b/Engine.Core/ActiveBehaviourCollector.cs
new file mode 100644
index 0000000..70e48d8
--- /dev/null
+++ b/Engine.Core/ActiveBehaviourCollector.cs
@@ -0,0 +1,123 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+
+using Syntriax.Engine.Core.Abstract;
+
+namespace Syntriax.Engine.Core;
+
+public class ActiveBehaviourCollector<T> : IBehaviourCollector<T> where T : class, IBehaviour
+{
+    public event IAssignable.UnassignEventHandler? OnUnassigned = null;
+    public event IHasGameManager.GameManagerAssignedEventHandler? OnGameManagerAssigned = null;
+
+    public event IBehaviourCollector<T>.CollectedEventHandler? OnCollected = null;
+    public event IBehaviourCollector<T>.RemovedEventHandler? OnRemoved = null;
+
+    private readonly List<T> monitoringBehaviours = new(32);
+    protected readonly List<T> activeBehaviours = new(32);
+    protected readonly Dictionary<IStateEnable, T> monitoringStateToBehaviour = new(32);
+
+    public IReadOnlyList<T> Behaviours => activeBehaviours;
+    public IGameManager GameManager { get; private set; } = null!;
+
+    public T this[Index index] => activeBehaviours[index];
+
+    public ActiveBehaviourCollector() { }
+    public ActiveBehaviourCollector(IGameManager gameManager) => Assign(gameManager);
+
+    private void OnHierarchyObjectRegistered(IGameManager manager, IHierarchyObject hierarchyObject)
+    {
+        hierarchyObject.BehaviourController.OnBehaviourAdded += OnBehaviourAdded;
+        hierarchyObject.BehaviourController.OnBehaviourRemoved += OnBehaviourRemoved;
+
+        foreach (IBehaviour item in hierarchyObject.BehaviourController)
+            OnBehaviourAdded(hierarchyObject.BehaviourController, item);
+    }
+
+    private void OnHierarchyObjectUnregistered(IGameManager manager, IHierarchyObject hierarchyObject)
+    {
+        hierarchyObject.BehaviourController.OnBehaviourAdded -= OnBehaviourAdded;
+        hierarchyObject.BehaviourController.OnBehaviourRemoved -= OnBehaviourRemoved;
+
+        foreach (IBehaviour item in hierarchyObject.BehaviourController)
+            OnBehaviourRemoved(hierarchyObject.BehaviourController, item);
+    }
+
+    protected virtual void OnBehaviourAdd(IBehaviour behaviour) { }
+    private void OnBehaviourAdded(IBehaviourController controller, IBehaviour behaviour)
+    {
+        if (behaviour is not T tBehaviour)
+            return;
+
+        monitoringBehaviours.Add(tBehaviour);
+        monitoringStateToBehaviour.Add(tBehaviour.StateEnable, tBehaviour);
+        tBehaviour.StateEnable.OnEnabledChanged += OnBehaviourStateChanged;
+        OnBehaviourStateChanged(tBehaviour.StateEnable, !tBehaviour.StateEnable.Enabled);
+    }
+
+    private void OnBehaviourStateChanged(IStateEnable sender, bool previousState)
+    {
+        T behaviour = monitoringStateToBehaviour[sender];
+        if (sender.Enabled)
+        {
+            activeBehaviours.Add(behaviour);
+            OnBehaviourAdd(behaviour);
+            OnCollected?.Invoke(this, behaviour);
+        }
+        else if (activeBehaviours.Contains(behaviour))
+        {
+            activeBehaviours.Remove(behaviour);
+            OnBehaviourRemove(behaviour);
+            OnRemoved?.Invoke(this, behaviour);
+        }
+    }
+
+    protected virtual void OnBehaviourRemove(IBehaviour behaviour) { }
+    private void OnBehaviourRemoved(IBehaviourController controller, IBehaviour behaviour)
+    {
+        if (behaviour is not T tBehaviour)
+            return;
+
+        if (!monitoringBehaviours.Remove(tBehaviour) || !monitoringStateToBehaviour.Remove(tBehaviour.StateEnable))
+            return;
+
+        tBehaviour.StateEnable.OnEnabledChanged -= OnBehaviourStateChanged;
+    }
+
+    public bool Assign(IGameManager gameManager)
+    {
+        if (GameManager is not null)
+            return false;
+
+        foreach (IHierarchyObject hierarchyObject in gameManager.HierarchyObjects)
+            OnHierarchyObjectRegistered(gameManager, hierarchyObject);
+
+        gameManager.OnHierarchyObjectRegistered += OnHierarchyObjectRegistered;
+        gameManager.OnHierarchyObjectUnRegistered += OnHierarchyObjectUnregistered;
+
+        GameManager = gameManager;
+        OnGameManagerAssigned?.Invoke(this);
+
+        return true;
+    }
+
+    public bool Unassign()
+    {
+        if (GameManager is null)
+            return false;
+
+        foreach (IHierarchyObject hierarchyObject in GameManager.HierarchyObjects)
+            OnHierarchyObjectUnregistered(GameManager, hierarchyObject);
+
+        GameManager.OnHierarchyObjectRegistered -= OnHierarchyObjectRegistered;
+        GameManager.OnHierarchyObjectUnRegistered -= OnHierarchyObjectUnregistered;
+
+        GameManager = null!;
+        OnUnassigned?.Invoke(this);
+        return true;
+    }
+
+    public IEnumerator<T> GetEnumerator() => activeBehaviours.GetEnumerator();
+    IEnumerator IEnumerable.GetEnumerator() => activeBehaviours.GetEnumerator();
+}
diff --git a/Engine.Core/ActiveBehaviourCollectorSorted.cs b/Engine.Core/ActiveBehaviourCollectorSorted.cs
new file mode 100644
index 0000000..e6807c2
--- /dev/null
+++ b/Engine.Core/ActiveBehaviourCollectorSorted.cs
@@ -0,0 +1,19 @@
+using System;
+
+using Syntriax.Engine.Core.Abstract;
+
+namespace Syntriax.Engine.Core;
+
+public class ActiveBehaviourCollectorSorted<T> : ActiveBehaviourCollector<T> where T : class, IBehaviour
+{
+    public Comparison<T>? SortBy { get; set; } = null;
+
+    protected override void OnBehaviourAdd(IBehaviour behaviour)
+    {
+        if (SortBy is not null)
+            activeBehaviours.Sort(SortBy);
+    }
+
+    public ActiveBehaviourCollectorSorted() { }
+    public ActiveBehaviourCollectorSorted(IGameManager gameManager) : base(gameManager) { }
+}