Add quick interactions locally

Quick Interactions/CSharp/Shared/DependencyInjection/ServiceCollection.Setup.cs

@@ -0,0 +1,56 @@
+using System;
+using System.Reflection;
+using System.Collections.Generic;
+using System.Linq;
+using Microsoft.Xna.Framework;
+using System.Diagnostics;
+using Barotrauma;
+
+namespace QIDependencyInjection
+{
+
+  public partial class ServiceCollection
+  {
+    /// <summary>
+    /// Will create mapping to itself.  
+    /// Usefull if you have object that doesn't implement any interface but has 
+    /// dependencies and should be injected
+    /// </summary>
+    public ServiceCollection Map<ImplementationType>() => Map<ImplementationType, ImplementationType>();
+    /// <summary>
+    /// Maps one type to another.  
+    /// GetService for ServiceType will return an object of ImplementationType.  
+    /// If ImplementationType is also in the mapping final type in the chain will be used as target type
+    /// </summary>
+    public ServiceCollection Map<ServiceType, ImplementationType>() => Map(typeof(ServiceType), typeof(ImplementationType));
+    public ServiceCollection Map(Type ImplementationType) => Map(ImplementationType, ImplementationType);
+    public ServiceCollection Map(Type ServiceType, Type ImplementationType)
+    {
+      Mapping[ServiceType] = ImplementationType;
+      return this;
+    }
+    /// <summary>
+    /// Will create a single object for that target type and map it to itself
+    /// if ServiceType is pointing to a type that has a singleton, that singleton will be returned 
+    /// instead of a new instance  
+    /// If T is a ServiceType, singleton will be created for resolved target type
+    /// </summary>
+    /// <typeparam name="T"> ImplementationType or ServiceType that is already mapped </typeparam>
+    /// <param name="args"> for TargetType constructor </param>
+    public T CreateSingleton<T>(object?[]? args = null) => (T)CreateSingleton(typeof(T), args);
+    public object CreateSingleton(Type T, object?[]? args = null)
+    {
+      Type TargetType = GetTargetType(T);
+
+      if (!Singletons.ContainsKey(TargetType))
+      {
+        Info($"creating a singleton for {TargetType}", new Color(255, 64, 255));
+        Singletons[TargetType] = Activator.CreateInstance(TargetType, args);
+        Map(TargetType);
+      }
+
+      return Singletons[TargetType];
+    }
+  }
+
+}