riversong code showcase

Source/Riversong/Game/DebugCommands/DrawGizmosSystem.cs

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+using System;
+using System.Collections.Generic;
+using Cysharp.Threading.Tasks;
+using UnityEngine;
+
+namespace DanieleMarotta.RiversongCodeShowcase
+{
+    [GameSystemGroup(typeof(DebugSystemGroup))]
+    public class DrawGizmosSystem : GameSystem, IInitializable, IDisposable
+    {
+        [InjectService]
+        private IEngine _engine;
+
+        private DrawGizmosSceneProxy _sceneProxy;
+
+        private List<IDrawGizmos> _callbacks = new();
+
+        public DrawGizmosSystem(IServiceLocator serviceLocator) : base(serviceLocator)
+        {
+        }
+
+        public UniTask InitializeAsync()
+        {
+#if DEBUG
+            _sceneProxy = new GameObject(nameof(DrawGizmosSceneProxy)).AddComponent<DrawGizmosSceneProxy>();
+            _sceneProxy.DrawGizmos += OnDrawGizmos;
+#endif
+
+            foreach (var system in _engine.Systems)
+                if (system is IDrawGizmos callback)
+                    _callbacks.Add(callback);
+
+            return UniTask.CompletedTask;
+        }
+
+        public void Dispose()
+        {
+            _sceneProxy.DrawGizmos -= OnDrawGizmos;
+        }
+
+        private void OnDrawGizmos(bool selected)
+        {
+            foreach (var callback in _callbacks) callback.DrawGizmos(selected);
+        }
+
+        private class DrawGizmosSceneProxy : MonoBehaviour
+        {
+            public event Action<bool> DrawGizmos;
+
+            private void OnDrawGizmos()
+            {
+                DrawGizmos?.Invoke(false);
+            }
+
+            private void OnDrawGizmosSelected()
+            {
+                DrawGizmos?.Invoke(true);
+            }
+        }
+    }
+}