From bb6990a80c499a93de9c23be7c8821d66c4c3377 Mon Sep 17 00:00:00 2001
From: Syntriax <Syntriax@gmail.com>
Date: Thu, 30 Nov 2023 10:39:40 +0300
Subject: [PATCH] feat: PreUpdate and FirstActiveFrame to Behaviour

---
 Engine.Core/Abstract/IBehaviourController.cs |  4 +++
 Engine.Core/BehaviourController.cs           |  3 ++
 Engine.Core/BehaviourOverride.cs             | 29 +++++++++++++++++++-
 3 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/Engine.Core/Abstract/IBehaviourController.cs b/Engine.Core/Abstract/IBehaviourController.cs
index b5a1f2c..28548bb 100644
--- a/Engine.Core/Abstract/IBehaviourController.cs
+++ b/Engine.Core/Abstract/IBehaviourController.cs
@@ -11,6 +11,10 @@ namespace Syntriax.Engine.Core.Abstract;
 /// </summary>
 public interface IBehaviourController : IAssignableGameObject
 {
+    /// <summary>
+    /// Callback triggered when the <see cref="Update(GameTime)"/> is called but right before the <see cref="OnUpdate"/> action is triggered.
+    /// </summary>
+    Action<IBehaviourController, GameTime>? OnPreUpdate { get; set; }
     /// <summary>
     /// Callback triggered when the <see cref="Update(GameTime)"/> is called.
     /// </summary>
diff --git a/Engine.Core/BehaviourController.cs b/Engine.Core/BehaviourController.cs
index ef60e98..cffe44b 100644
--- a/Engine.Core/BehaviourController.cs
+++ b/Engine.Core/BehaviourController.cs
@@ -10,6 +10,7 @@ namespace Syntriax.Engine.Core;
 
 public class BehaviourController : IBehaviourController
 {
+    public Action<IBehaviourController, GameTime>? OnPreUpdate { get; set; }
     public Action<IBehaviourController, GameTime>? OnUpdate { get; set; } = null;
     public Action<IBehaviourController, GameTime>? OnPreDraw { get; set; } = null;
 
@@ -111,8 +112,10 @@ public class BehaviourController : IBehaviourController
         if (!GameObject.StateEnable.Enabled)
             return;
 
+        OnPreUpdate?.Invoke(this, gameTime);
         OnUpdate?.Invoke(this, gameTime);
     }
+
     public void UpdatePreDraw(GameTime gameTime)
     {
         if (!GameObject.StateEnable.Enabled)
diff --git a/Engine.Core/BehaviourOverride.cs b/Engine.Core/BehaviourOverride.cs
index 0bc67d5..5c2e9f3 100644
--- a/Engine.Core/BehaviourOverride.cs
+++ b/Engine.Core/BehaviourOverride.cs
@@ -1,4 +1,3 @@
-using System;
 using Microsoft.Xna.Framework;
 
 using Syntriax.Engine.Core.Abstract;
@@ -7,6 +6,8 @@ namespace Syntriax.Engine.Core;
 
 public abstract class BehaviourOverride : Behaviour
 {
+    private bool isInitializedThisFrame = false;
+
     protected IGameObject GameObject => BehaviourController.GameObject;
     protected ITransform Transform => BehaviourController.GameObject.Transform;
 
@@ -23,6 +24,9 @@ public abstract class BehaviourOverride : Behaviour
     protected virtual void OnInitialize() { }
     private void OnInitialize(IInitialize _)
     {
+        isInitializedThisFrame = true;
+
+        BehaviourController.OnPreUpdate += PreUpdate;
         BehaviourController.OnPreDraw += PreDraw;
         BehaviourController.OnUpdate += Update;
         OnInitialize();
@@ -31,11 +35,34 @@ public abstract class BehaviourOverride : Behaviour
     protected virtual void OnFinalize() { }
     private void OnFinalize(IInitialize _)
     {
+        BehaviourController.OnPreUpdate -= PreUpdate;
         BehaviourController.OnPreDraw -= PreDraw;
         BehaviourController.OnUpdate -= Update;
         OnFinalize();
     }
 
+    protected virtual void OnPreUpdatePreEnabledCheck(GameTime time) { }
+    protected virtual void OnPreUpdate(GameTime time) { }
+    private void PreUpdate(IBehaviourController _, GameTime time)
+    {
+        OnPreUpdatePreEnabledCheck(time);
+
+        if (!StateEnable.Enabled)
+            return;
+
+        if (isInitializedThisFrame)
+            FirstActiveFrame(time);
+
+        OnPreUpdate(time);
+    }
+
+    protected virtual void OnFirstActiveFrame(GameTime time) { }
+    private void FirstActiveFrame(GameTime time)
+    {
+        OnFirstActiveFrame(time);
+        isInitializedThisFrame = false;
+    }
+
     protected virtual void OnUpdatePreEnabledCheck(GameTime time) { }
     protected virtual void OnUpdate(GameTime time) { }
     private void Update(IBehaviourController _, GameTime time)