From 8d95d499246741b075ffa2e3fb6cfdd0119d91ef Mon Sep 17 00:00:00 2001
From: Stephen <stephenafoster88@gmail.com>
Date: Sat, 17 Feb 2024 13:15:56 +0000
Subject: [PATCH] Check for undefined layer and throw on collision actor
 insertion

---
 .../CollisionComponent.cs                      |  8 +++++++-
 .../Layers/UndefinedLayerException.cs          | 18 ++++++++++++++++++
 2 files changed, 25 insertions(+), 1 deletion(-)
 create mode 100644 src/cs/MonoGame.Extended.Collisions/Layers/UndefinedLayerException.cs

diff --git a/src/cs/MonoGame.Extended.Collisions/CollisionComponent.cs b/src/cs/MonoGame.Extended.Collisions/CollisionComponent.cs
index 9677c14f..d615220e 100644
--- a/src/cs/MonoGame.Extended.Collisions/CollisionComponent.cs
+++ b/src/cs/MonoGame.Extended.Collisions/CollisionComponent.cs
@@ -104,7 +104,13 @@ namespace MonoGame.Extended.Collisions
         /// <param name="target">Target to insert.</param>
         public void Insert(ICollisionActor target)
         {
-            _layers[target.LayerName ?? DEFAULT_LAYER_NAME].Space.Insert(target);
+            var layerName = target.LayerName ?? DEFAULT_LAYER_NAME;
+            if (!_layers.TryGetValue(layerName, out var layer))
+            {
+                throw new UndefinedLayerException(layerName);
+            }
+
+            layer.Space.Insert(target);
         }
 
         /// <summary>
diff --git a/src/cs/MonoGame.Extended.Collisions/Layers/UndefinedLayerException.cs b/src/cs/MonoGame.Extended.Collisions/Layers/UndefinedLayerException.cs
new file mode 100644
index 00000000..a27b5b6b
--- /dev/null
+++ b/src/cs/MonoGame.Extended.Collisions/Layers/UndefinedLayerException.cs
@@ -0,0 +1,18 @@
+namespace MonoGame.Extended.Collisions.Layers;
+
+using System;
+
+/// <summary>
+/// Thrown when the collision system has no layer defined with the specified name
+/// </summary>
+public class UndefinedLayerException : Exception
+{
+    /// <summary>
+    /// Thrown when the collision system has no layer defined with the specified name
+    /// </summary>
+    /// <param name="layerName">The undefined layer name</param>
+    public UndefinedLayerException(string layerName)
+        : base($"Layer with name '{layerName}' is undefined")
+    {
+    }
+}