Adjust operation generation for root client (Azure#52394)

* Adjust operation for root client

* update comment

* typo

Author: live1206

eng/packages/http-client-csharp-mgmt/generator/Azure.Generator.Management/src/Visitors/RestClientVisitor.cs

@@ -1,11 +1,17 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License.
 
+using Azure.Core.Pipeline;
+using Azure.Generator.Management.Utilities;
 using Microsoft.TypeSpec.Generator.ClientModel;
 using Microsoft.TypeSpec.Generator.ClientModel.Providers;
 using Microsoft.TypeSpec.Generator.Primitives;
 using Microsoft.TypeSpec.Generator.Providers;
+using Microsoft.TypeSpec.Generator.Statements;
+using System;
 using System.IO;
+using System.Linq;
+using static Microsoft.TypeSpec.Generator.Snippets.Snippet;
 
 namespace Azure.Generator.Management.Visitors;
 
@@ -16,11 +22,20 @@ internal class RestClientVisitor : ScmLibraryVisitor
     {
         if (type is not null && type is ClientProvider client)
         {
-            // omit methods for ClientProvider, MPG will implement its own client methods
-            // put create request methods to client directly and remove RestClientProvider
-            type.Update(methods: [.. client.RestClient.Methods], modifiers: TransfromPublicModifiersToInternal(type), relativeFilePath: TransformRelativeFilePathForClient(type));
+            // handle root client
+            if (client.ClientOptions is not null)
+            {
+                UpdateRootClient(client);
+            }
+            else
+            {
+                // omit methods for ClientProvider, MPG will implement its own client methods
+                // put create request methods to client directly
+                type.Update(methods: [.. client.RestClient.Methods], modifiers: TransformPublicModifiersToInternal(type), relativeFilePath: TransformRelativeFilePathForClient(type));
+            }
         }
 
+        // remove RestClientProvider
         if (type is RestClientProvider)
         {
             return null;
@@ -29,10 +44,58 @@ internal class RestClientVisitor : ScmLibraryVisitor
         return type;
     }
 
+    private void UpdateRootClient(ClientProvider rootClient)
+    {
+        // fields
+        var apiVersionField = new FieldProvider(FieldModifiers.Private | FieldModifiers.ReadOnly, typeof(string), "_apiVersion", rootClient);
+        var endpointField = new FieldProvider(FieldModifiers.Private | FieldModifiers.ReadOnly, typeof(Uri), "_endpoint", rootClient);
+
+        // properties
+        var pipelineProperty = new PropertyProvider(
+            description: $"The HTTP pipeline for sending and receiving REST requests and responses.",
+            modifiers: MethodSignatureModifiers.Public,
+            type: typeof(HttpPipeline),
+            name: "Pipeline",
+            body: new AutoPropertyBody(false),
+            enclosingType: rootClient);
+        var clientDiagnosticsProperty = new PropertyProvider(
+            description: $"The ClientDiagnostics is used to provide tracing support for the client library.",
+            modifiers: MethodSignatureModifiers.Internal,
+            type: typeof(ClientDiagnostics),
+            name: "ClientDiagnostics",
+            body: new AutoPropertyBody(false),
+            enclosingType: rootClient);
+
+        // constructor
+        var clientDiagnosticsParam = new ParameterProvider("clientDiagnostics", $"The ClientDiagnostics is used to provide tracing support for the client library.", typeof(ClientDiagnostics));
+        var pipelineParam = new ParameterProvider("pipeline", $"The HTTP pipeline for sending and receiving REST requests and responses.", typeof(HttpPipeline));
+        var endpointParam = new ParameterProvider("endpoint", $"Service endpoint.", typeof(Uri), null);
+        var apiVersionParam = new ParameterProvider("apiVersion", $"The API version to use for this client.", typeof(string));
+        var ctorBody = new MethodBodyStatement[]
+        {
+            clientDiagnosticsProperty.Assign(clientDiagnosticsParam).Terminate(),
+            endpointField.Assign(endpointParam).Terminate(),
+            pipelineProperty.Assign(pipelineParam).Terminate(),
+            apiVersionField.Assign(apiVersionParam).Terminate(),
+        };
+        var ctor = new ConstructorProvider(
+            new ConstructorSignature(rootClient.Type, null, MethodSignatureModifiers.Public, [clientDiagnosticsParam, pipelineParam, endpointParam, apiVersionParam]),
+            ctorBody,
+            rootClient);
+
+        rootClient.Update(
+            fields:[apiVersionField, endpointField],
+            methods: [.. rootClient.RestClient.Methods], // put create request methods to client directly
+            modifiers: TransformPublicModifiersToInternal(rootClient),
+            relativeFilePath: TransformRelativeFilePathForClient(rootClient),
+            properties: [pipelineProperty, clientDiagnosticsProperty],
+            constructors: [ctor, ConstructorProviderHelpers.BuildMockingConstructor(rootClient)]);
+    }
+
     private static string TransformRelativeFilePathForClient(TypeProvider type)
         => Path.Combine("src", "Generated", "RestOperations", $"{type.Name}RestOperations.cs");
 
-    private static TypeSignatureModifiers TransfromPublicModifiersToInternal(TypeProvider type)
+    private static TypeSignatureModifiers TransformPublicModifiersToInternal(TypeProvider type)
     {
         var modifiers = type.DeclarationModifiers;
         if (modifiers.HasFlag(TypeSignatureModifiers.Public))

eng/packages/http-client-csharp-mgmt/generator/TestProjects/Local/Mgmt-TypeSpec/routes.tsp

@@ -9,22 +9,20 @@ using Azure.ResourceManager;
 
 namespace MgmtTypeSpec;
 
-interface FooTasks {
-  /**
-   * Runs the input conditions against input object metadata properties and designates matched objects in response.
-   */
-  @autoRoute
-  previewActions is ArmProviderActionSync<
-    Request = FooPreviewAction,
-    Response = FooPreviewAction,
-    Scope = SubscriptionActionScope,
-    Parameters = {
-      @path
-      @segment("locations")
-      location: Azure.Core.azureLocation;
-    }
-  >;
-}
+/**
+ * Runs the input conditions against input object metadata properties and designates matched objects in response.
+ */
+@autoRoute
+op previewActions is ArmProviderActionSync<
+  Request = FooPreviewAction,
+  Response = FooPreviewAction,
+  Scope = SubscriptionActionScope,
+  Parameters = {
+    @path
+    @segment("locations")
+    location: Azure.Core.azureLocation;
+  }
+>;
 
 model FooPreviewAction {
   /** The action to be performed. */