From 9af627b0608ebed8a77947000000eb3dc9fa3b08 Mon Sep 17 00:00:00 2001
From: Niyaz Kashafutdinov <niyaz.kashafutdinov@colossi.games>
Date: Mon, 25 Mar 2024 22:11:40 +0300
Subject: [PATCH] feat: parent container

---
 ReDI.Tests/ParentContainerTest.cs | 40 +++++++++++++++++++++++++++++++
 ReDI/Container.cs                 | 12 ++++++----
 ReDI/ContainerBuilder.cs          |  4 ++--
 3 files changed, 49 insertions(+), 7 deletions(-)
 create mode 100644 ReDI.Tests/ParentContainerTest.cs

diff --git a/ReDI.Tests/ParentContainerTest.cs b/ReDI.Tests/ParentContainerTest.cs
new file mode 100644
index 0000000..61ec76e
--- /dev/null
+++ b/ReDI.Tests/ParentContainerTest.cs
@@ -0,0 +1,40 @@
+using NUnit.Framework;
+
+namespace ReDI.Tests;
+
+[TestFixture]
+public class ParentContainerTest
+{
+    [Test]
+    public void TestParentContainerBuilding()
+    {
+        var containerBuilder = new ContainerBuilder();
+        containerBuilder.AddModule<ABModule>();
+        var container = containerBuilder.Build();
+        Assert.IsNotNull(container);
+        var containerWithParent = containerBuilder.Build(container);
+        Assert.IsNotNull(containerWithParent);
+        Assert.That(containerWithParent, Is.Not.SameAs(container));
+    }
+    
+    [Test]
+    public void TestParentContainerResolves()
+    {
+        var containerBuilder = new ContainerBuilder();
+        containerBuilder.AddModule<ABModule>();
+        var container = containerBuilder.Build();
+        Assert.IsNotNull(container);
+        var emptyContainerBuilder = new ContainerBuilder();
+        var containerWithParent = emptyContainerBuilder.Build(container);
+        Assert.IsNotNull(containerWithParent);
+        Assert.That(containerWithParent, Is.Not.SameAs(container));
+
+        var abc = container.Resolve<ServiceABC>();
+        Assert.IsNotNull(abc);
+        Assert.IsInstanceOf<ServiceABC>(abc);
+        
+        var abcFromParent = containerWithParent.Resolve<ServiceABC>();
+        Assert.IsNotNull(abcFromParent);
+        Assert.IsInstanceOf<ServiceABC>(abcFromParent);
+    }
+}
\ No newline at end of file
diff --git a/ReDI/Container.cs b/ReDI/Container.cs
index 5c9b852..9b45f9b 100644
--- a/ReDI/Container.cs
+++ b/ReDI/Container.cs
@@ -12,10 +12,12 @@ public class Container : IDisposable
         private readonly Dictionary<Type, HashSet<ServiceRegistration>> _registrationsByInterface = new Dictionary<Type, HashSet<ServiceRegistration>>();
         
         private bool _isDisposed;
+        private Container _parent;
         private HashSet<Type> _constructingTypes = new HashSet<Type>();
         
-        internal Container(IEnumerable<BindingInfo> bindings)
+        internal Container(IEnumerable<BindingInfo> bindings, Container parent)
         {
+            _parent = parent;
             var toBuild = new HashSet<ServiceRegistration>();
             
             foreach (var binding in bindings)
@@ -67,7 +69,7 @@ public void Dispose()
         public T? Resolve<T>() where T : class
         {
             var obj = Resolve(typeof(T));
-            return obj != null ? (T)obj : null;
+            return obj != null ? (T)obj : _parent?.Resolve<T>();
         }
         
         public object? Resolve(Type type)
@@ -76,15 +78,15 @@ public void Dispose()
 
             if (IsGenericList(type))
             {
-                return ResolveList(type);
+                return ResolveList(type) ?? _parent?.ResolveList(type);
             }
             else if (IsGeneric(type))
             {
-                return ResolveGeneric(type);
+                return ResolveGeneric(type) ?? _parent?.ResolveGeneric(type);
             }
             else
             {
-                return ResolveSingle(type);
+                return ResolveSingle(type) ?? _parent?.ResolveSingle(type);
             }
         }
         
diff --git a/ReDI/ContainerBuilder.cs b/ReDI/ContainerBuilder.cs
index 0682317..d8e61a0 100644
--- a/ReDI/ContainerBuilder.cs
+++ b/ReDI/ContainerBuilder.cs
@@ -14,7 +14,7 @@ public void AddModule<TModule>(TModule module) where TModule : Module
             _moduleManager.RegisterModule(module);
         }
 
-        public Container Build()
+        public Container Build(Container parentContainer = null)
         {
             var typeManager = new TypeManager();
             var modules = _moduleManager.GetRegisteredModules();
@@ -25,7 +25,7 @@ public Container Build()
             }
 
             var bindings = typeManager.GetBindings();
-            return new Container(bindings);
+            return new Container(bindings, parentContainer);
         }
     }
 }
\ No newline at end of file