Feature: turn GetFirstEnabledActions into GetAction

Aplib.Core/Tactics/AnyOfTactic.cs

@@ -35,16 +35,19 @@ public AnyOfTactic(List<Tactic> subTactics)
         public AnyOfTactic(List<Tactic> subTactics, Func<bool> guard) : this(subTactics) => Guard = guard;
 
         /// <inheritdoc/>
-        public override List<PrimitiveTactic> GetFirstEnabledActions()
+        public override Action? GetAction()
         {
-            List<PrimitiveTactic> primitiveTactics = new();
+            List<Action> actions = new();
 
             foreach (Tactic subTactic in SubTactics)
             {
-                primitiveTactics.AddRange(subTactic.GetFirstEnabledActions());
+                Action? action = subTactic.GetAction();
+
+                if (action is not null)
+                    actions.Add(action);
             }
 
-            return primitiveTactics;
+            return actions[ThreadSafeRandom.Next(actions.Count)];
         }
     }
 }

Aplib.Core/Tactics/FirstOfTactic.cs

@@ -26,14 +26,14 @@ public FirstOfTactic(List<Tactic> subTactics, Func<bool> guard) : base(subTactic
         }
 
         /// <inheritdoc/>
-        public override List<PrimitiveTactic> GetFirstEnabledActions()
+        public override Action? GetAction()
         {
             foreach (Tactic subTactic in SubTactics)
             {
-                List<PrimitiveTactic> firstOfTactics = subTactic.GetFirstEnabledActions();
+                Action? action = subTactic.GetAction();
 
-                if (firstOfTactics.Count > 0)
-                    return firstOfTactics;
+                if (action is not null && action.IsActionable())
+                    return action;
             }
 
             return new();

Aplib.Core/Tactics/PrimitiveTactic.cs

@@ -27,7 +27,7 @@ public class PrimitiveTactic : Tactic
         public PrimitiveTactic(Action action, Func<bool> guard) : base(guard) => Action = action;
 
         /// <inheritdoc/>
-        public override List<PrimitiveTactic> GetFirstEnabledActions() => IsActionable() ? new() { this } : new();
+        public override Action? GetAction() => IsActionable() ? Action : null;
 
         /// <inheritdoc/>
         public override bool IsActionable() => base.IsActionable() && Action.IsActionable();

Aplib.Core/Tactics/Tactic.cs

@@ -1,5 +1,4 @@
 using System;
-using System.Collections.Generic;
 
 namespace Aplib.Core.Tactics
 {
@@ -27,10 +26,10 @@ protected Tactic()
         protected Tactic(Func<bool> guard) => Guard = guard;
 
         /// <summary>
-        /// Gets the first enabled primitive actions.
+        /// Gets the enabled action.
         /// </summary>
-        /// <returns>A list of primitive tactics that are enabled.</returns>
-        public abstract List<PrimitiveTactic> GetFirstEnabledActions();
+        /// <returns>An action that is enabled.</returns>
+        public abstract Action? GetAction();
 
         /// <summary>
         /// Determines whether the tactic is actionable.

Aplib.Core/ThreadSafeRandom.cs

@@ -0,0 +1,32 @@
+using System;
+using System.Threading.Tasks;
+
+internal static class ThreadSafeRandom
+{
+    [ThreadStatic]
+    private static Random? _local;
+    private static readonly Random _global = new();
+
+    private static Random _instance
+    {
+        get
+        {
+            if (_local is null)
+            {
+                int seed;
+                lock (_global)
+                {
+                    seed = _global.Next();
+                }
+
+                _local = new Random(seed);
+            }
+
+            return _local;
+        }
+    }
+
+    public static int Next() => _instance.Next();
+
+    public static int Next(int maxValue) => _instance.Next(maxValue);
+}

Aplib.Tests/Core/Tactics/TacticTests.cs

@@ -4,7 +4,9 @@
 namespace Aplib.Tests.Core.Tactics;
 public class TacticTests
 {
-    private readonly Action _emptyAction = new(() => { });
+    private readonly Action _emptyAction = new(effect: () => { });
+    private static string _result = "abc";
+    private readonly Action _filledAction = new(effect: () => _result = "def");
 
     private static bool TrueGuard() => true;
 
@@ -16,18 +18,18 @@ public class TacticTests
     /// Then the result should be the first subtactic.
     /// </summary>
     [Fact]
-    public void GetFirstEnabledActions_WhenTacticTypeIsFirstOf_ReturnsEnabledPrimitiveTactics()
+    public void GetAction_WhenTacticTypeIsFirstOf_ReturnsEnabledPrimitiveTactics()
     {
         // Arrange
         PrimitiveTactic tactic1 = new(_emptyAction);
-        PrimitiveTactic tactic2 = new(_emptyAction);
+        PrimitiveTactic tactic2 = new(_filledAction);
         FirstOfTactic parentTactic = new([tactic1, tactic2]);
 
         // Act
-        List<PrimitiveTactic> enabledActions = parentTactic.GetFirstEnabledActions();
+        Action? enabledAction = parentTactic.GetAction();
 
         // Assert
-        Assert.Contains(tactic1, enabledActions);
+        Assert.Equal(_emptyAction, enabledAction);
     }
 
     /// <summary>
@@ -36,18 +38,18 @@ public void GetFirstEnabledActions_WhenTacticTypeIsFirstOf_ReturnsEnabledPrimiti
     /// Then the result should be the first subtactic.
     /// </summary>
     [Fact]
-    public void GetFirstEnabledActions_WhenTacticTypeIsFirstOfAndGuardEnabled_ReturnsEnabledPrimitiveTactics()
+    public void GetAction_WhenTacticTypeIsFirstOfAndGuardEnabled_ReturnsEnabledPrimitiveTactics()
     {
         // Arrange
         PrimitiveTactic tactic1 = new(_emptyAction);
-        PrimitiveTactic tactic2 = new(_emptyAction);
+        PrimitiveTactic tactic2 = new(_filledAction);
         FirstOfTactic parentTactic = new([tactic1, tactic2], TrueGuard);
 
         // Act
-        List<PrimitiveTactic> enabledActions = parentTactic.GetFirstEnabledActions();
+        Action? enabledAction = parentTactic.GetAction();
 
         // Assert
-        Assert.Contains(tactic1, enabledActions);
+        Assert.Equal(_emptyAction, enabledAction);
     }
 
     /// <summary>
@@ -56,19 +58,18 @@ public void GetFirstEnabledActions_WhenTacticTypeIsFirstOfAndGuardEnabled_Return
     /// Then the result should contain all the subtactics.
     /// </summary>
     [Fact]
-    public void GetFirstEnabledActions_WhenTacticTypeIsAnyOf_ReturnsEnabledPrimitiveTactics()
+    public void GetAction_WhenTacticTypeIsAnyOf_ReturnsEnabledPrimitiveTactics()
     {
         // Arrange
         PrimitiveTactic tactic1 = new(_emptyAction);
         PrimitiveTactic tactic2 = new(_emptyAction);
         AnyOfTactic parentTactic = new([tactic1, tactic2]);
 
         // Act
-        List<PrimitiveTactic> enabledActions = parentTactic.GetFirstEnabledActions();
+        Action? enabledAction = parentTactic.GetAction();
 
         // Assert
-        Assert.Contains(tactic1, enabledActions);
-        Assert.Contains(tactic2, enabledActions);
+        Assert.Equal(_emptyAction, enabledAction);
     }
 
     /// <summary>
@@ -77,16 +78,16 @@ public void GetFirstEnabledActions_WhenTacticTypeIsAnyOf_ReturnsEnabledPrimitive
     /// Then the result should contain the primitive tactic.
     /// </summary>
     [Fact]
-    public void GetFirstEnabledActions_WhenTacticTypeIsPrimitiveAndActionIsActionable_ReturnsEnabledPrimitiveTactic()
+    public void GetAction_WhenTacticTypeIsPrimitiveAndActionIsActionable_ReturnsEnabledPrimitiveTactic()
     {
         // Arrange
         PrimitiveTactic tactic = new(_emptyAction, TrueGuard);
 
         // Act
-        List<PrimitiveTactic> enabledActions = tactic.GetFirstEnabledActions();
+        Action? enabledAction = tactic.GetAction();
 
         // Assert
-        Assert.Contains(tactic, enabledActions);
+        Assert.Equal(_emptyAction, enabledAction);
     }
 
     /// <summary>
@@ -95,16 +96,16 @@ public void GetFirstEnabledActions_WhenTacticTypeIsPrimitiveAndActionIsActionabl
     /// Then the result should be an empty list.
     /// </summary>
     [Fact]
-    public void GetFirstEnabledActions_WhenTacticTypeIsPrimitiveAndActionIsNotActionable_ReturnsEmptyList()
+    public void GetAction_WhenTacticTypeIsPrimitiveAndActionIsNotActionable_ReturnsEmptyList()
     {
         // Arrange
         PrimitiveTactic tactic = new(_emptyAction, FalseGuard);
 
         // Act
-        List<PrimitiveTactic> enabledActions = tactic.GetFirstEnabledActions();
+        Action? enabledAction = tactic.GetAction();
 
         // Assert
-        Assert.Empty(enabledActions);
+        Assert.Null(enabledAction);
     }
 
     /// <summary>