feat(behavior-tree): calling Reset() now triggers End on active nodes

Previously calling reset on a BehaviorTree did not call `End()` because it was not performant. Nodes
that return continue on a tree are now registered as active and removed after returning continue.
Allowing them to be discovered at the top level by the BehaviorTree without traversing the entire
system.

Assets/FluidBehaviorTree/Runtime/BehaviorTree/BehaviorTree.cs

@@ -1,14 +1,24 @@
-using CleverCrow.Fluid.BTs.TaskParents;
+using System.Collections.Generic;
+using CleverCrow.Fluid.BTs.TaskParents;
 using CleverCrow.Fluid.BTs.Tasks;
 using UnityEngine;
 
 namespace CleverCrow.Fluid.BTs.Trees {
-    public class BehaviorTree {
+    public interface IBehaviorTree {
+        int TickCount { get; }
+
+        void AddActiveTask (ITask task);
+        void RemoveActiveTask (ITask task);
+    }
+
+    public class BehaviorTree : IBehaviorTree {
         private readonly GameObject _owner;
+        private readonly List<ITask> _tasks = new List<ITask>();
 
         public int TickCount { get; private set; }
-        
+
         public TaskRoot Root { get; } = new TaskRoot();
+        public IReadOnlyList<ITask> ActiveTasks => _tasks;
 
         public BehaviorTree (GameObject owner) {
             _owner = owner;
@@ -18,13 +28,18 @@ public BehaviorTree (GameObject owner) {
         public TaskStatus Tick () {
             var status = Root.Update();
             if (status != TaskStatus.Continue) {
-                TickCount++;
+                Reset();
             }
 
             return status;
         }
 
         public void Reset () {
+            foreach (var task in _tasks) {
+                task.End();
+            }
+
+            _tasks.Clear();
             TickCount++;
         }
 
@@ -54,5 +69,13 @@ private void SyncNodes (ITaskParent taskParent) {
                 }
             }
         }
+
+        public void AddActiveTask (ITask task) {
+            _tasks.Add(task);
+        }
+
+        public void RemoveActiveTask (ITask task) {
+            _tasks.Remove(task);
+        }
     }
 }

Assets/FluidBehaviorTree/Runtime/Decorators/DecoratorBase.cs

@@ -13,7 +13,7 @@ public abstract class DecoratorBase : ITaskParent {
         public bool Enabled { get; set; } = true;
 
         public GameObject Owner { get; set; }
-        public BehaviorTree ParentTree { get; set; }
+        public IBehaviorTree ParentTree { get; set; }
         public TaskStatus LastStatus { get; private set; }
 
         public ITask Child => Children.Count > 0 ? Children[0] : null;

Assets/FluidBehaviorTree/Runtime/TaskParents/TaskParentBase.cs

@@ -5,7 +5,7 @@
 
 namespace CleverCrow.Fluid.BTs.TaskParents {
     public abstract class TaskParentBase : ITaskParent {
-        public BehaviorTree ParentTree { get; set; }
+        public IBehaviorTree ParentTree { get; set; }
         public TaskStatus LastStatus { get; private set; }
 
         public string Name { get; set; }

Assets/FluidBehaviorTree/Runtime/Tasks/ITask.cs

@@ -22,7 +22,7 @@ public interface ITask {
         /// <summary>
         /// Tree this node belongs to
         /// </summary>
-        BehaviorTree ParentTree { get; set; }
+        IBehaviorTree ParentTree { get; set; }
 
         /// <summary>
         /// Last status returned by Update

Assets/FluidBehaviorTree/Runtime/Tasks/TaskBase.cs

@@ -7,11 +7,12 @@ public abstract class TaskBase : ITask {
         private bool _start;
         private bool _exit;
         private int _lastTickCount;
+        private bool _active;
 
         public string Name { get; set; }
         public bool Enabled { get; set; } = true;
         public GameObject Owner { get; set; }
-        public BehaviorTree ParentTree { get; set; }
+        public IBehaviorTree ParentTree { get; set; }
 
         public TaskStatus LastStatus { get; private set; }
 
@@ -32,9 +33,12 @@ public TaskStatus Update () {
             var status = GetUpdate();
             LastStatus = status;
 
-            // Soft reset since the node has completed
             if (status != TaskStatus.Continue) {
+                if (_active) ParentTree?.RemoveActiveTask(this);
                 Exit();
+            } else if (!_active) {
+                ParentTree?.AddActiveTask(this);
+                _active = true;
             }
 
             return status;
@@ -56,6 +60,7 @@ private void UpdateTicks () {
         /// Reset the node to be re-used
         /// </summary>
         public void Reset () {
+            _active = false;
             _start = false;
             _exit = false;
         }

Assets/FluidBehaviorTree/Tests/Editor/BehaviorTrees/BehaviorTreeTest.cs

@@ -1,6 +1,8 @@
 using System.Collections.Generic;
+using System.Linq;
 using CleverCrow.Fluid.BTs.TaskParents.Composites;
 using CleverCrow.Fluid.BTs.Tasks;
+using CleverCrow.Fluid.BTs.Testing;
 using NSubstitute;
 using NUnit.Framework;
 using UnityEngine;
@@ -121,6 +123,27 @@ public void It_should_increase_the_tick_count () {
 
                 Assert.AreEqual(1, _tree.TickCount);
             }
+
+            [Test]
+            public void It_should_call_End_on_active_nodes () {
+                var task = A.TaskStub().Build();
+
+                _tree.AddActiveTask(task);
+                _tree.Reset();
+
+                task.Received(1).End();
+            }
+
+            [Test]
+            public void It_should_not_call_End_on_active_nodes_twice_if_called_again () {
+                var task = A.TaskStub().Build();
+
+                _tree.AddActiveTask(task);
+                _tree.Reset();
+                _tree.Reset();
+
+                task.Received(1).End();
+            }
         }
 
         public class TickMethod : BehaviorTreeTest {
@@ -218,5 +241,28 @@ public void Does_not_run_reset_on_2nd_action_if_1st_fails () {
                 }
             }
         }
+
+        public class AddActiveTaskMethod : BehaviorTreeTest {
+            [Test]
+            public void It_should_add_an_active_task () {
+                var task = A.TaskStub().Build();
+
+                _tree.AddActiveTask(task);
+
+                Assert.IsTrue(_tree.ActiveTasks.Contains(task));
+            }
+        }
+
+        public class RemoveActiveTaskMethod : BehaviorTreeTest {
+            [Test]
+            public void It_should_add_an_active_task () {
+                var task = A.TaskStub().Build();
+
+                _tree.AddActiveTask(task);
+                _tree.RemoveActiveTask(task);
+
+                Assert.IsFalse(_tree.ActiveTasks.Contains(task));
+            }
+        }
     }
 }