add entity preset support

Blarg.GameFramework/Blarg.GameFramework.csproj

@@ -222,6 +222,9 @@
     <Compile Include="TileMap\Json\JsonTileMap.cs" />
     <Compile Include="TileMap\Json\TileMapSerializer.cs" />
     <Compile Include="IO\FileOpenMode.cs" />
+    <Compile Include="Entities\EntityPreset.cs" />
+    <Compile Include="Entities\EntityPresetArgs.cs" />
+    <Compile Include="Entities\SystemComponents\EntityPresetComponent.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildExtensionsPath32)\Microsoft\Portable\$(TargetFrameworkVersion)\Microsoft.Portable.CSharp.targets" />
   <ItemGroup>

Blarg.GameFramework/Entities/EntityManager.cs

@@ -13,6 +13,7 @@ namespace Blarg.GameFramework.Entities
 	using ComponentStore = Dictionary<Type, Dictionary<Entity, Component>>;
 	using GlobalComponentStore = Dictionary<Type, Component>;
 	using ComponentSystemList = List<ComponentSystem>;
+	using EntityPresetMap = Dictionary<Type, EntityPreset>;
 
 	public class EntityManager : IDisposable
 	{
@@ -22,6 +23,7 @@ namespace Blarg.GameFramework.Entities
 		ComponentStore _components;
 		GlobalComponentStore _globalComponents;
 		ComponentSystemList _componentSystems;
+		EntityPresetMap _presets;
 
 		EntityPool _entityPool;
 
@@ -37,6 +39,7 @@ namespace Blarg.GameFramework.Entities
 			_components = new ComponentStore();
 			_globalComponents = new GlobalComponentStore();
 			_componentSystems = new ComponentSystemList();
+			_presets = new EntityPresetMap();
 
 			_entityPool = new EntityPool(this);
 
@@ -82,6 +85,29 @@ namespace Blarg.GameFramework.Entities
 
 		#endregion
 
+		#region Preset management
+
+		public void AddPreset<T>() where T : EntityPreset
+		{
+			if (_presets.ContainsKey(typeof(T)))
+			    throw new InvalidOperationException("EntityPreset of that type is already registered.");
+
+			T preset = (T)Activator.CreateInstance(typeof(T), this);
+			_presets.Add(typeof(T), preset);
+		}
+
+		public void RemovePreset<T>() where T : EntityPreset
+		{
+			_presets.Remove(typeof(T));
+		}
+
+		public void RemoveAllPresets()
+		{
+			_presets.Clear();
+		}
+
+		#endregion
+
 		#region Entity management
 
 		public Entity Add()
@@ -91,6 +117,23 @@ namespace Blarg.GameFramework.Entities
 			return entity;
 		}
 
+		public Entity AddUsingPreset<T>() where T : EntityPreset
+		{
+			return AddUsingPreset<T>(new EntityPreset.EmptyEntityPresetArgs());
+		}
+
+		public Entity AddUsingPreset<T>(EntityPresetArgs args) where T : EntityPreset
+		{
+			var preset = _presets.Get(typeof(T));
+			if (preset == null)
+				throw new InvalidOperationException("Cannot add entity using a non-existant preset.");
+
+			var entity = preset.Create(args);
+			entity.Add<EntityPresetComponent>().PresetType = typeof(T);
+
+			return entity;
+		}
+
 		public Entity GetFirstWith<T>() where T : Component
 		{
 			EntityToComponentMap componentEntities = _components.Get(typeof(T));

Blarg.GameFramework/Entities/EntityPreset.cs

@@ -0,0 +1,24 @@
+using System;
+
+namespace Blarg.GameFramework.Entities
+{
+	public abstract class EntityPreset
+	{
+		public struct EmptyEntityPresetArgs : EntityPresetArgs
+		{
+		}
+
+		public readonly EntityManager EntityManager;
+
+		public EntityPreset(EntityManager entityManager)
+		{
+			if (entityManager == null)
+				throw new ArgumentNullException("entityManager");
+
+			EntityManager = entityManager;
+		}
+
+		public abstract Entity Create(EntityPresetArgs args);
+	}
+}
+

Blarg.GameFramework/Entities/EntityPresetArgs.cs

@@ -0,0 +1,9 @@
+using System;
+
+namespace Blarg.GameFramework.Entities
+{
+	public interface EntityPresetArgs
+	{
+	}
+}
+

Blarg.GameFramework/Entities/SystemComponents/EntityPresetComponent.cs

@@ -0,0 +1,15 @@
+using System;
+
+namespace Blarg.GameFramework.Entities.SystemComponents
+{
+	public class EntityPresetComponent : Component
+	{
+		public Type PresetType;
+
+		public override void Reset()
+		{
+			PresetType = null;
+		}
+	}
+}
+