From 8a6f010fbb138e60555851054e1b4f9facaf39a8 Mon Sep 17 00:00:00 2001
From: Antony Male <antony.male@gmail.com>
Date: Fri, 25 Sep 2015 10:57:46 +0100
Subject: [PATCH] Add support for namespace transformations to ViewManager

---
 Stylet/ViewManager.cs               | 38 +++++++++++++++++++++----
 StyletUnitTests/ViewManagerTests.cs | 43 +++++++++++++++++++++++++++--
 2 files changed, 74 insertions(+), 7 deletions(-)

diff --git a/Stylet/ViewManager.cs b/Stylet/ViewManager.cs
index 71e3f0e..39383b1 100644
--- a/Stylet/ViewManager.cs
+++ b/Stylet/ViewManager.cs
@@ -49,7 +49,7 @@ namespace Stylet
     /// </summary>
     public class ViewManagerConfig
     {
-        private List<Assembly> _viewAssemblies;
+        private List<Assembly> _viewAssemblies = new List<Assembly>();
 
         /// <summary>
         /// Gets and sets the assemblies which are used for IoC container auto-binding and searching for Views.
@@ -70,12 +70,21 @@ namespace Stylet
         /// </summary>
         public Func<Type, object> ViewFactory { get; set; }
 
+
+        private Dictionary<string, string> _namespaceTransformations = new Dictionary<string, string>();
+
         /// <summary>
-        /// Instantiates a new instance of the <see cref="ViewManagerConfig"/> class
+        /// Gets and sets a set of transformations to be applied to the ViewModel's namespace: string to find -> string to replace it with
         /// </summary>
-        public ViewManagerConfig()
+        public Dictionary<string, string> NamespaceTransformations
         {
-            this.ViewAssemblies = new List<Assembly>();
+            get { return this._namespaceTransformations; }
+            set
+            {
+                if (value == null)
+                    throw new ArgumentNullException();
+                this._namespaceTransformations = value;
+            }
         }
     }
 
@@ -96,6 +105,11 @@ namespace Stylet
         /// </summary>
         protected Func<Type, object> ViewFactory { get; set; }
 
+        /// <summary>
+        /// Gets and sets a set of transformations to be applied to the ViewModel's namespace: string to find -> string to replace it with
+        /// </summary>
+        protected Dictionary<string, string> NamespaceTransformations { get; set; }
+
         /// <summary>
         /// Initialises a new instance of the <see cref="ViewManager"/> class, with the given viewFactory
         /// </summary>
@@ -105,8 +119,10 @@ namespace Stylet
             // Config.ViewAssemblies cannot be null - ViewManagerConfig ensures this
             if (config.ViewFactory == null)
                 throw new ArgumentNullException("config.ViewFactory");
+
             this.ViewAssemblies = config.ViewAssemblies;
             this.ViewFactory = config.ViewFactory;
+            this.NamespaceTransformations = config.NamespaceTransformations;
         }
 
         /// <summary>
@@ -193,7 +209,19 @@ namespace Stylet
         /// <returns>View type name</returns>
         protected virtual string ViewTypeNameForModelTypeName(string modelTypeName)
         {
-            return Regex.Replace(modelTypeName, @"(?<=.)ViewModel(?=s?\.)|ViewModel$", "View");
+            string transformed = modelTypeName;
+
+            foreach (var transformation in this.NamespaceTransformations)
+            {
+                if (transformed.StartsWith(transformation.Key + "."))
+                {
+                    transformed = transformation.Value + transformed.Substring(transformation.Key.Length);
+                    break;
+                }
+            }
+
+            transformed = Regex.Replace(transformed, @"(?<=.)ViewModel(?=s?\.)|ViewModel$", "View");
+            return transformed;
         }
 
         /// <summary>
diff --git a/StyletUnitTests/ViewManagerTests.cs b/StyletUnitTests/ViewManagerTests.cs
index bd53ace..ef7378a 100644
--- a/StyletUnitTests/ViewManagerTests.cs
+++ b/StyletUnitTests/ViewManagerTests.cs
@@ -132,6 +132,27 @@ namespace StyletUnitTests
             this.viewManager = new AccessibleViewManager(this.viewManagerConfig);
         }
 
+        [Test]
+        public void ViewManagerConfigRejectsNullViewAssemblies()
+        {
+            var config = new ViewManagerConfig();
+            Assert.Throws<ArgumentNullException>(() => config.ViewAssemblies = null);
+        }
+
+        [Test]
+        public void ViewManagerConfigRejectsNullNamespaceTransformations()
+        {
+            var config = new ViewManagerConfig();
+            Assert.Throws<ArgumentNullException>(() => config.NamespaceTransformations = null);
+        }
+
+        [Test]
+        public void ViewManagerRejectsNullViewFactory()
+        {
+            var config = new ViewManagerConfig();
+            Assert.Throws<ArgumentNullException>(() => new ViewManager(config));
+        }
+
         [Test]
         public void OnModelChangedDoesNothingIfNoChange()
         {
@@ -327,8 +348,6 @@ namespace StyletUnitTests
             model.Verify(x => x.AttachView(view));
         }
 
-        
-
         [Test]
         public void ViewNameResolutionWorksAsExpected()
         {
@@ -348,5 +367,25 @@ namespace StyletUnitTests
 
             Assert.AreEqual("ViewModels.TestView", viewManager.ViewTypeNameForModelTypeName("ViewModels.TestViewModel"));
         }
+
+        [Test]
+        public void NamespaceTransformationsTransformsNamespace()
+        {
+            this.viewManagerConfig.NamespaceTransformations["Foo.Bar"] = "Baz.Yay";
+            var viewManager = new AccessibleViewManager(this.viewManagerConfig);
+
+            Assert.AreEqual("Baz.Yay.ThingView", viewManager.ViewTypeNameForModelTypeName("Foo.Bar.ThingViewModel"));
+            Assert.AreEqual("Baz.Yay.Thing", viewManager.ViewTypeNameForModelTypeName("Foo.Bar.Thing"));
+        }
+
+        [Test]
+        public void NamespaceTransformationsTransformOnlyFirstMatch()
+        {
+            this.viewManagerConfig.NamespaceTransformations["Foo.Bar"] = "Baz.Yay";
+            this.viewManagerConfig.NamespaceTransformations["Baz.Yay"] = "One.Two";
+
+            Assert.AreEqual("Baz.Yay.ThingView", viewManager.ViewTypeNameForModelTypeName("Foo.Bar.ThingViewModel"));
+            Assert.AreEqual("One.Two.ThingView", viewManager.ViewTypeNameForModelTypeName("Baz.Yay.ThingViewModel"));
+        }
     }
 }