feat: basic tween system added

Engine.Systems/Tween/TweenManager.cs

@@ -0,0 +1,66 @@
+using System.Collections;
+
+using Syntriax.Engine.Core;
+using Syntriax.Engine.Core.Abstract;
+
+namespace Syntriax.Engine.Systems.Tween;
+
+public class TweenManager : HierarchyObject
+{
+    private CoroutineManager coroutineManager = null!;
+
+    private readonly Dictionary<ITween, IEnumerator> runningCoroutines = [];
+
+    public ITween StartTween(float duration, TweenSetCallback? setCallback = null)
+    {
+        Tween tween = new(duration);
+        tween.OnUpdated += tween => setCallback?.Invoke(tween.Value);
+        runningCoroutines.Add(tween, coroutineManager.StartCoroutine(RunTween(tween)));
+        return tween;
+    }
+
+    private IEnumerator RunTween(Tween tween)
+    {
+        tween.State = TweenState.Playing;
+        yield return null;
+
+        while (true)
+        {
+            if (tween.State.CheckFlag(TweenState.Cancelled | TweenState.Completed))
+                break;
+
+            if (tween.State.CheckFlag(TweenState.Paused))
+            {
+                yield return null;
+                continue;
+            }
+
+            tween.Counter += GameManager.Time.DeltaTime;
+            yield return null;
+        }
+
+        runningCoroutines.Remove(tween);
+    }
+
+    public void CancelTween(ITween tween)
+    {
+        if (!runningCoroutines.TryGetValue(tween, out IEnumerator? runningCoroutine))
+            return;
+
+        tween.State = TweenState.Cancelled;
+        coroutineManager.StopCoroutine(runningCoroutine);
+        runningCoroutines.Remove(tween);
+    }
+
+    protected override void OnEnteringHierarchy(IGameManager gameManager)
+    {
+        coroutineManager = gameManager.FindHierarchyObject<CoroutineManager>() ?? throw new($"No {nameof(CoroutineManager)} was found in the game manager");
+    }
+
+    protected override void OnExitingHierarchy(IGameManager gameManager)
+    {
+        coroutineManager = null!;
+    }
+
+    public delegate void TweenSetCallback(float t);
+}