riversong code showcase

Source/Riversong/Game/Input/CancelActionSystem.cs

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+using System;
+using System.Collections.Generic;
+using UnityEngine.InputSystem;
+
+namespace DanieleMarotta.RiversongCodeShowcase
+{
+    [Service(typeof(ICancelAction))]
+    [GameSystemGroup(typeof(LateGameSystemGroup))]
+    public class CancelActionSystem : GameSystem, IUpdatable, ICancelAction
+    {
+        private readonly List<(int, Func<CancelActionType, bool>)> _handlers = new();
+
+        private Comparison<(int, Func<CancelActionType, bool>)> _handlerComparison;
+
+        public CancelActionSystem(IServiceLocator serviceLocator) : base(serviceLocator)
+        {
+        }
+
+        public void Update()
+        {
+            if (!TryGetCancelActionType(out var cancelActionType)) return;
+
+            foreach (var (_, handler) in _handlers)
+                if (handler.Invoke(cancelActionType))
+                    return;
+        }
+
+        public void AddHandler(int priority, Func<CancelActionType, bool> cancelAction)
+        {
+            _handlerComparison ??= (handler, otherHandler) =>
+            {
+                var (handlerPriority, _) = handler;
+                var (otherHandlerPriority, _) = otherHandler;
+                return otherHandlerPriority.CompareTo(handlerPriority);
+            };
+
+            _handlers.Add((priority, cancelAction));
+            _handlers.Sort(_handlerComparison);
+        }
+
+        private static bool TryGetCancelActionType(out CancelActionType cancelActionType)
+        {
+            if (Keyboard.current.escapeKey.wasPressedThisFrame)
+            {
+                cancelActionType = CancelActionType.EscapeKey;
+                return true;
+            }
+
+            if (Mouse.current.rightButton.wasPressedThisFrame)
+            {
+                cancelActionType = CancelActionType.RightMouseButton;
+                return true;
+            }
+
+            cancelActionType = CancelActionType.None;
+            return false;
+        }
+    }
+}