From d9756e0c3d04164a7a1400a191de6bd9a04a135b Mon Sep 17 00:00:00 2001
From: Evan Hemsley <evan@moonside.games>
Date: Sat, 15 Jun 2019 11:40:42 -0700
Subject: [PATCH] update component uses a callback now

---
 src/Engine.cs      | 15 +++++++++++++--
 test/EngineTest.cs | 45 ++++++++++++++++++++++++---------------------
 2 files changed, 37 insertions(+), 23 deletions(-)

diff --git a/src/Engine.cs b/src/Engine.cs
index 0400795..c4bdb3c 100644
--- a/src/Engine.cs
+++ b/src/Engine.cs
@@ -38,11 +38,22 @@ namespace Encompass {
             return this.componentManager.GetActiveComponentByType<TComponent>();
         }
 
-        protected void UpdateComponent<TComponent>(TComponent originalComponent, TComponent newComponent) where TComponent : struct, IComponent {
+        internal void UpdateComponentInWorld<TComponent>(TComponent originalComponent, TComponent newComponent) where TComponent : struct, IComponent {
             if (mutateComponentTypes.Contains(typeof(TComponent))) {
                 this.componentManager.UpdateComponent(originalComponent, newComponent);
             } else {
-                throw new IllegalComponentMutationException("Engine {0} tried to mutate undeclared Component {1}", this.GetType().ToString(), typeof(TComponent).ToString());
+                throw new IllegalComponentMutationException("Engine {0} tried to mutate undeclared Component {1}", this.GetType().Name, typeof(TComponent).Name);
+            }
+        }
+
+        protected void UpdateComponent<TComponent>(TComponent component, Func<TComponent, TComponent> updateFunction) where TComponent : struct, IComponent {
+            var updatedComponent = updateFunction(component);
+            this.UpdateComponentInWorld(component, updatedComponent);
+        }
+
+        protected void UpdateComponents<TComponent>(IEnumerable<TComponent> components, Func<TComponent, TComponent> updateFunction) where TComponent : struct, IComponent {
+            foreach (var component in components) {
+                this.UpdateComponent(component, updateFunction);
             }
         }
     }
diff --git a/test/EngineTest.cs b/test/EngineTest.cs
index ae43df8..20df383 100644
--- a/test/EngineTest.cs
+++ b/test/EngineTest.cs
@@ -8,14 +8,14 @@ using System;
 namespace Tests {
     public class EngineTest
     {
-        static IEnumerable<MockComponent> components;
-        static MockComponent component;
+        static IEnumerable<MockComponent> resultComponents;
+        static MockComponent resultComponent;
 
         public class ReadComponentsTestEngine : Engine
         {
             public override void Update(float dt)
             {
-                components = this.ReadComponents<MockComponent>();
+                resultComponents = this.ReadComponents<MockComponent>();
             }
         }
 
@@ -23,7 +23,7 @@ namespace Tests {
         {
             public override void Update(float dt)
             {
-                component = this.ReadComponent<MockComponent>();
+                resultComponent = this.ReadComponent<MockComponent>();
             }
         }
 
@@ -50,8 +50,8 @@ namespace Tests {
 
             world.Update(0.01f);
 
-            Assert.Contains(mockComponent, components.ToList());
-            Assert.Contains(mockComponentB, components.ToList());
+            Assert.Contains(mockComponent, resultComponents.ToList());
+            Assert.Contains(mockComponentB, resultComponents.ToList());
         }
 
         [Test]
@@ -72,7 +72,7 @@ namespace Tests {
 
             world.Update(0.01f);
 
-            Assert.AreEqual(mockComponent, component);
+            Assert.AreEqual(mockComponent, resultComponent);
         }
 
         [Test]
@@ -104,12 +104,13 @@ namespace Tests {
         {
             public override void Update(float dt)
             {
-                var originalComponent = this.ReadComponent<MockComponent>();
-                var newComponent = this.ReadComponent<MockComponent>();
-                newComponent.myInt = 420;
-                newComponent.myString = "blaze it";
-                this.UpdateComponent(originalComponent, newComponent);
-                component = this.ReadComponent<MockComponent>();
+                var component = this.ReadComponent<MockComponent>();
+                this.UpdateComponent(component, (MockComponent comp) => {
+                    comp.myInt = 420;
+                    comp.myString = "blaze it";
+                    return comp;
+                });
+                resultComponent = this.ReadComponent<MockComponent>();
             }
         }
 
@@ -131,19 +132,20 @@ namespace Tests {
 
             world.Update(0.01f);
 
-            Assert.AreEqual(420, component.myInt);
-            Assert.AreEqual("blaze it", component.myString);
+            Assert.AreEqual(420, resultComponent.myInt);
+            Assert.AreEqual("blaze it", resultComponent.myString);
         }
 
         public class UndeclaredUpdateComponentTestEngine : Engine
         {
             public override void Update(float dt)
             {
-                var originalComponent = this.ReadComponent<MockComponent>();
-                var newComponent = this.ReadComponent<MockComponent>();
-                newComponent.myInt = 420;
-                newComponent.myString = "blaze it";
-                this.UpdateComponent(originalComponent, newComponent);
+                var component = this.ReadComponent<MockComponent>();
+                this.UpdateComponent(component, (MockComponent comp) => {
+                    comp.myInt = 420;
+                    comp.myString = "blaze it";
+                    return comp;
+                });
                 component = this.ReadComponent<MockComponent>();
             }
         }
@@ -164,7 +166,8 @@ namespace Tests {
 
             var world = worldBuilder.Build();
 
-            Assert.Throws<IllegalComponentMutationException>(() => world.Update(0.01f));
+            var ex =Assert.Throws<IllegalComponentMutationException>(() => world.Update(0.01f));
+            Assert.That(ex.Message, Is.EqualTo("Engine UndeclaredUpdateComponentTestEngine tried to mutate undeclared Component MockComponent"));
         }
     }
 }