From 5a01b01215c74b47d0ef1abcac51b04102b68f4d Mon Sep 17 00:00:00 2001
From: Syntriax <Syntriax@gmail.com>
Date: Fri, 24 Nov 2023 17:03:21 +0300
Subject: [PATCH] feat: Added IAssignable.Unassign()

---
 Engine.Core/Abstract/Assignable/IAssignable.cs | 18 +++++++++++++++++-
 Engine.Core/Behaviour.cs                       | 14 ++++++++++++++
 Engine.Core/BehaviourController.cs             | 11 +++++++++++
 Engine.Core/GameManager.cs                     | 11 +++++++++++
 Engine.Core/GameObject.cs                      | 14 ++++++++++++++
 Engine.Core/StateEnable.cs                     | 13 ++++++++++++-
 6 files changed, 79 insertions(+), 2 deletions(-)

diff --git a/Engine.Core/Abstract/Assignable/IAssignable.cs b/Engine.Core/Abstract/Assignable/IAssignable.cs
index d377e57..32fdb9c 100644
--- a/Engine.Core/Abstract/Assignable/IAssignable.cs
+++ b/Engine.Core/Abstract/Assignable/IAssignable.cs
@@ -1,6 +1,22 @@
+using System;
+
 namespace Syntriax.Engine.Core.Abstract;
 
 /// <summary>
 /// Indicates the class implementing it has Assignable fields that are necessary for the engine to work properly.
 /// </summary>
-public interface IAssignable { }
+public interface IAssignable
+{
+    /// <summary>
+    /// Callback triggered when the <see cref="IAssignable"/>'s fields are unassigned and completely ready to recycle.
+    /// </summary> 
+    Action<IAssignable>? OnUnassigned { get; set; }
+
+    /// <summary>
+    /// Unassign <see cref="IAssignable"/>'s all fields and make it ready to recycle.
+    /// </summary>
+    /// <returns> 
+    /// <see cref="true"/>, if the fields are unsigned successfully, <see cref="false"/> if not.
+    /// </returns>
+    bool Unassign();
+}
diff --git a/Engine.Core/Behaviour.cs b/Engine.Core/Behaviour.cs
index abe8a3d..34bf242 100644
--- a/Engine.Core/Behaviour.cs
+++ b/Engine.Core/Behaviour.cs
@@ -6,6 +6,7 @@ namespace Syntriax.Engine.Core;
 
 public abstract class Behaviour : IBehaviour
 {
+    public Action<IAssignable>? OnUnassigned { get; set; } = null;
     public Action<IAssignableStateEnable>? OnStateEnableAssigned { get; set; } = null;
     public Action<IAssignableBehaviourController>? OnBehaviourControllerAssigned { get; set; } = null;
 
@@ -73,6 +74,19 @@ public abstract class Behaviour : IBehaviour
         return true;
     }
 
+    public bool Unassign()
+    {
+        if (Initialized)
+            return false;
+
+        _stateEnable = null!;
+        _behaviourController = null!;
+        _stateEnable.Unassign();
+
+        OnUnassigned?.Invoke(this);
+        return true;
+    }
+
     public bool Initialize()
     {
         if (Initialized)
diff --git a/Engine.Core/BehaviourController.cs b/Engine.Core/BehaviourController.cs
index 3bf59d4..76aa214 100644
--- a/Engine.Core/BehaviourController.cs
+++ b/Engine.Core/BehaviourController.cs
@@ -15,6 +15,7 @@ public class BehaviourController : IBehaviourController
 
     public Action<IBehaviourController, IBehaviour>? OnBehaviourAdded { get; set; } = null;
     public Action<IBehaviourController, IBehaviour>? OnBehaviourRemoved { get; set; } = null;
+    public Action<IAssignable>? OnUnassigned { get; set; } = null;
     public Action<IAssignableGameObject>? OnGameObjectAssigned { get; set; } = null;
 
 
@@ -95,6 +96,16 @@ public class BehaviourController : IBehaviourController
         return true;
     }
 
+    public bool Unassign()
+    {
+        if (GameObject.Initialized)
+            return false;
+
+        _gameObject = null!;
+        OnUnassigned?.Invoke(this);
+        return true;
+    }
+
     public void Update(GameTime gameTime)
     {
         if (!GameObject.StateEnable.Enabled)
diff --git a/Engine.Core/GameManager.cs b/Engine.Core/GameManager.cs
index c6efd69..64450cd 100644
--- a/Engine.Core/GameManager.cs
+++ b/Engine.Core/GameManager.cs
@@ -14,6 +14,7 @@ public class GameManager : IInitialize
 {
     public Action<IInitialize>? OnInitialized { get; set; } = null;
     public Action<IInitialize>? OnFinalized { get; set; } = null;
+    public Action<IAssignable>? OnUnassigned { get; set; } = null;
     public Action<IAssignableStateEnable>? OnStateEnableAssigned { get; set; } = null;
 
 
@@ -98,6 +99,16 @@ public class GameManager : IInitialize
         return true;
     }
 
+    public bool Unassign()
+    {
+        if (Initialized)
+            return false;
+
+        _stateEnable = null!;
+        OnUnassigned?.Invoke(this);
+        return true;
+    }
+
     public void Update(GameTime time)
     {
         foreach (var gameObject in GameObjects)
diff --git a/Engine.Core/GameObject.cs b/Engine.Core/GameObject.cs
index 8fc6918..47d6acc 100644
--- a/Engine.Core/GameObject.cs
+++ b/Engine.Core/GameObject.cs
@@ -11,6 +11,7 @@ public class GameObject : IGameObject
 {
     public Action<IAssignableStateEnable>? OnStateEnableAssigned { get; set; } = null;
     public Action<IAssignableTransform>? OnTransformAssigned { get; set; } = null;
+    public Action<IAssignable>? OnUnassigned { get; set; } = null;
     public Action<IAssignableBehaviourController>? OnBehaviourControllerAssigned { get; set; } = null;
 
     public Action<IEntity>? OnNameChanged { get; set; } = null;
@@ -126,6 +127,19 @@ public class GameObject : IGameObject
         return true;
     }
 
+    public bool Unassign()
+    {
+        if (Initialized)
+            return false;
+
+        _stateEnable = null!;
+        _transform = null!;
+        _behaviourController = null!;
+
+        OnUnassigned?.Invoke(this);
+        return true;
+    }
+
     public GameObject() { OnBehaviourControllerAssigned += ConnectBehaviourController; }
     private void ConnectBehaviourController(IAssignableBehaviourController controller)
     {
diff --git a/Engine.Core/StateEnable.cs b/Engine.Core/StateEnable.cs
index 1c047cb..9815430 100644
--- a/Engine.Core/StateEnable.cs
+++ b/Engine.Core/StateEnable.cs
@@ -6,6 +6,7 @@ namespace Syntriax.Engine.Core;
 
 public class StateEnable : IStateEnable
 {
+    public Action<IAssignable>? OnUnassigned { get; set; } = null;
     public Action<IAssignableEntity>? OnEntityAssigned { get; set; } = null;
     public Action<IStateEnable>? OnEnabledChanged { get; set; } = null;
 
@@ -29,11 +30,21 @@ public class StateEnable : IStateEnable
 
     public bool Assign(IEntity entity)
     {
-        if (_entity is not null) // TODO: IInitialize Maybe?
+        if (_entity is not null) // TODO: Add IInitialize to IAssignable or IEntity maybe?
             return false;
 
         _entity = entity;
         OnEntityAssigned?.Invoke(this);
         return true;
     }
+
+    public bool Unassign()
+    {
+        if (_entity is null)
+            return false;
+
+        _entity = null!;
+        OnUnassigned?.Invoke(this);
+        return true;
+    }
 }