From 591cd980d955bcfc2f5017265b1a901d82005db2 Mon Sep 17 00:00:00 2001
From: thatcosmonaut <evan@moonside.games>
Date: Wed, 13 Nov 2019 13:15:43 -0800
Subject: [PATCH] runtime type HasComponent

---
 encompass-cs/ComponentMessageManager.cs | 15 ++++++++++
 encompass-cs/Engine.cs                  | 32 +++++++++++++++++++++
 test/ComponentTest.cs                   | 38 ++++++++++++++++++++++++-
 3 files changed, 84 insertions(+), 1 deletion(-)

diff --git a/encompass-cs/ComponentMessageManager.cs b/encompass-cs/ComponentMessageManager.cs
index c42716b..3cde86c 100644
--- a/encompass-cs/ComponentMessageManager.cs
+++ b/encompass-cs/ComponentMessageManager.cs
@@ -268,16 +268,31 @@ namespace Encompass
             return entityToTypeToComponentID.ContainsKey(entity) && entityToTypeToComponentID[entity].ContainsKey(typeof(TComponent));
         }
 
+        internal bool HasExistingOrPendingComponent(Entity entity, Type type)
+        {
+            return entityToTypeToComponentID.ContainsKey(entity) && entityToTypeToComponentID[entity].ContainsKey(type);
+        }
+
         internal bool HasExistingComponent<TComponent>(Entity entity) where TComponent : struct, IComponent
         {
             return entityToTypeToExistingComponentID.ContainsKey(entity) && entityToTypeToExistingComponentID[entity].ContainsKey(typeof(TComponent));
         }
 
+        internal bool HasExistingComponent(Entity entity, Type type)
+        {
+            return entityToTypeToExistingComponentID.ContainsKey(entity) && entityToTypeToExistingComponentID[entity].ContainsKey(type);
+        }
+
         internal bool HasPendingComponent<TComponent>(Entity entity) where TComponent : struct, IComponent
         {
             return entityToTypeToPendingComponentID.ContainsKey(entity) && entityToTypeToPendingComponentID[entity].ContainsKey(typeof(TComponent));
         }
 
+        internal bool HasPendingComponent(Entity entity, Type type)
+        {
+            return entityToTypeToPendingComponentID.ContainsKey(entity) && entityToTypeToPendingComponentID[entity].ContainsKey(type);
+        }
+
         internal IComponent GetComponentByID(Guid componentID)
         {
             if (componentIDToComponent.ContainsKey(componentID))
diff --git a/encompass-cs/Engine.cs b/encompass-cs/Engine.cs
index 92f01d1..c68184f 100644
--- a/encompass-cs/Engine.cs
+++ b/encompass-cs/Engine.cs
@@ -362,6 +362,38 @@ namespace Encompass
             }
         }
 
+        /// <summary>
+        /// Returns true if the Entity has a Component of the given Type.
+        /// </summary>
+        /// <exception cref="Encompass.Exceptions.IllegalReadException">
+        /// Thrown when the Engine does not declare that is Reads the given Component Type.
+        /// </exception>
+        protected bool HasComponent(Entity entity, Type type)
+        {
+            var pending = typeof(PendingComponentMessage<>).MakeGenericType(type);
+            var existing = typeof(ComponentMessage<>).MakeGenericType(type);
+
+            var pendingRead = receiveTypes.Contains(pending);
+            var existingRead = receiveTypes.Contains(existing);
+
+            if (pendingRead && existingRead)
+            {
+                return componentMessageManager.HasExistingOrPendingComponent(entity, type);
+            }
+            else if (existingRead)
+            {
+                return componentMessageManager.HasExistingComponent(entity, type);
+            }
+            else if (pendingRead)
+            {
+                return componentMessageManager.HasPendingComponent(entity, type);
+            }
+            else
+            {
+                throw new IllegalReadException("Engine {0} tried to read undeclared Component {1}", GetType().Name, type.Name);
+            }
+        }
+
         /// <summary>
         /// Sets Component data for the specified Component Type on the specified Entity. If Component data for this Type already existed on the Entity, the component data is overwritten.
         /// </summary>
diff --git a/test/ComponentTest.cs b/test/ComponentTest.cs
index 3cd553b..4ae154a 100644
--- a/test/ComponentTest.cs
+++ b/test/ComponentTest.cs
@@ -135,7 +135,7 @@ namespace Tests
             worldBuilder.AddEngine(new ReadMockComponentEngine());
 
             var entity = worldBuilder.CreateEntity();
-            worldBuilder.SetComponent(entity, new MockComponent {});
+            worldBuilder.SetComponent(entity, new MockComponent { });
 
             var world = worldBuilder.Build();
             world.Update(0.01);
@@ -312,6 +312,42 @@ namespace Tests
             world.Update(0.01);
         }
 
+        [Receives(typeof(HasComponentTestMessage))]
+        [Reads(typeof(MockComponent))]
+        class HasComponentWithRuntimeTypeEngine : Engine
+        {
+            public override void Update(double dt)
+            {
+                foreach (var hasComponentTestEngine in ReadMessages<HasComponentTestMessage>())
+                {
+                    Assert.IsTrue(HasComponent(hasComponentTestEngine.entity, typeof(MockComponent)));
+                }
+            }
+        }
+
+        [Test]
+        public void HasComponentWithRuntimeType()
+        {
+            var worldBuilder = new WorldBuilder();
+            worldBuilder.AddEngine(new HasComponentWithRuntimeTypeEngine());
+
+            var entity = worldBuilder.CreateEntity();
+
+            MockComponent mockComponent;
+            mockComponent.myInt = 3;
+            mockComponent.myString = "hello";
+
+            worldBuilder.SetComponent(entity, mockComponent);
+
+            HasComponentTestMessage hasComponentTestMessage;
+            hasComponentTestMessage.entity = entity;
+            worldBuilder.SendMessage(hasComponentTestMessage);
+
+            var world = worldBuilder.Build();
+
+            world.Update(0.01);
+        }
+
         struct RemoveComponentTestMessage : IMessage
         {
             public Entity entity;