CQRS Agent Query Migration: Add AgentManagerExtensions with CQRS-backed GetCurrentAgentNameViaQuery (#271)

* Initial plan

* CQRS agent query migration: add AgentManagerExtensions with GetCurrentAgentNameViaQuery

Co-authored-by: michaelbeale-IL <63321611+michaelbeale-IL@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: michaelbeale-IL <63321611+michaelbeale-IL@users.noreply.github.com>

Author: Copilot

src/Libraries/ACATCore.Tests.Configuration/CQRSPatternTests.cs

@@ -14,7 +14,9 @@
 using ACAT.Core.Configuration;
 using ACAT.Core.Patterns.CQRS;
 using ACAT.Core.Patterns.CQRS.Samples;
+using ACAT.Core.PanelManagement;
 using ACAT.Core.PanelManagement.Common;
+using Microsoft.Extensions.DependencyInjection;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using System;
 
@@ -222,5 +224,69 @@ public void GetActiveAgentNameQueryHandler_ReturnsEmptyStringWhenNoAgent()
 
             Assert.AreEqual(string.Empty, result);
         }
+
+        // ----------------------------------------------------------------
+        // AgentManagerExtensions.GetCurrentAgentNameViaQuery – behaviour
+        // ----------------------------------------------------------------
+
+        [TestCleanup]
+        public void ResetServiceProvider()
+        {
+            // Ensure Context.ServiceProvider is reset after every test so
+            // that DI-enabled tests do not leak state into subsequent tests.
+            Context.ServiceProvider = null;
+        }
+
+        [TestMethod]
+        public void GetCurrentAgentNameViaQuery_WithoutServiceProvider_FallsBackToDirectCall()
+        {
+            Context.ServiceProvider = null;
+            var fake = new FakeAgentManager { CurrentAgentName = "FallbackAgent" };
+
+            string result = fake.GetCurrentAgentNameViaQuery();
+
+            Assert.AreEqual("FallbackAgent", result);
+        }
+
+        [TestMethod]
+        public void GetCurrentAgentNameViaQuery_WithoutServiceProvider_NullAgentName_ReturnsEmpty()
+        {
+            Context.ServiceProvider = null;
+            var fake = new FakeAgentManager { CurrentAgentName = null };
+
+            string result = fake.GetCurrentAgentNameViaQuery();
+
+            Assert.AreEqual(string.Empty, result);
+        }
+
+        [TestMethod]
+        public void GetCurrentAgentNameViaQuery_WithServiceProvider_RoutesViaHandler()
+        {
+            var fake = new FakeAgentManager { CurrentAgentName = "DirectAgent" };
+            var services = new ServiceCollection();
+            // Register a handler backed by a *different* fake so we can prove
+            // the call was routed through the DI handler and not the direct path.
+            var handlerFake = new FakeAgentManager { CurrentAgentName = "HandlerAgent" };
+            services.AddTransient<IQueryHandler<GetActiveAgentNameQuery, string>>(
+                _ => new GetActiveAgentNameQueryHandler(handlerFake));
+            Context.ServiceProvider = services.BuildServiceProvider();
+
+            string result = fake.GetCurrentAgentNameViaQuery();
+
+            Assert.AreEqual("HandlerAgent", result);
+        }
+
+        [TestMethod]
+        public void GetCurrentAgentNameViaQuery_WithServiceProvider_NoHandlerRegistered_FallsBackToDirectCall()
+        {
+            var fake = new FakeAgentManager { CurrentAgentName = "DirectFallback" };
+            // Build a DI container that does NOT register the query handler.
+            var services = new ServiceCollection();
+            Context.ServiceProvider = services.BuildServiceProvider();
+
+            string result = fake.GetCurrentAgentNameViaQuery();
+
+            Assert.AreEqual("DirectFallback", result);
+        }
     }
 }

src/Libraries/ACATCore/ACAT.Core.csproj

@@ -593,6 +593,7 @@
     <Compile Include="Patterns\CQRS\Samples\GetConfigurationValueQueryHandler.cs" />
     <Compile Include="Patterns\CQRS\Samples\GetActiveAgentNameQuery.cs" />
     <Compile Include="Patterns\CQRS\Samples\GetActiveAgentNameQueryHandler.cs" />
+    <Compile Include="Patterns\CQRS\AgentManagerExtensions.cs" />
   </ItemGroup>
   <ItemGroup>
     <EmbeddedResource Include="ActuatorManagement\UI\ActuatorErrorForm.resx">

src/Libraries/ACATCore/Patterns/CQRS/AgentManagerExtensions.cs

@@ -0,0 +1,74 @@
+////////////////////////////////////////////////////////////////////////////
+//
+// Copyright 2013-2019; 2023 Intel Corporation
+// SPDX-License-Identifier: Apache-2.0
+//
+//
+// AgentManagerExtensions.cs
+//
+// Extension methods for IAgentManager that provide CQRS-based wrappers
+// around agent query operations.  Each method resolves the registered
+// IQueryHandler from the DI container when available and falls back to
+// calling the IAgentManager method directly when running outside a
+// DI-configured environment (e.g., unit tests or legacy entry points).
+//
+// Usage – call-site migration:
+//
+//   Before:
+//       string name = Context.AppAgentMgr.GetCurrentAgentName();
+//
+//   After:
+//       string name = Context.AppAgentMgr.GetCurrentAgentNameViaQuery();
+//
+// The extension method body can be simplified to the CQRS-only path once
+// every call site has been migrated and legacy fallback is no longer needed.
+//
+////////////////////////////////////////////////////////////////////////////
+
+using ACAT.Core.AgentManagement;
+using ACAT.Core.PanelManagement;
+using ACAT.Core.Patterns.CQRS.Samples;
+
+namespace ACAT.Core.Patterns.CQRS
+{
+    /// <summary>
+    /// Extension methods for <see cref="IAgentManager"/> that route agent
+    /// queries through the CQRS <see cref="IQueryHandler{TQuery,TResult}"/>
+    /// infrastructure when available, falling back to direct
+    /// <see cref="IAgentManager"/> calls when a DI container is not configured.
+    /// </summary>
+    public static class AgentManagerExtensions
+    {
+        /// <summary>
+        /// Returns the name of the currently active agent by dispatching a
+        /// <see cref="GetActiveAgentNameQuery"/> through the registered
+        /// <see cref="IQueryHandler{TQuery,TResult}"/>.
+        /// </summary>
+        /// <remarks>
+        /// When <see cref="Context.ServiceProvider"/> is configured the call
+        /// is routed through the DI-registered handler so that the CQRS
+        /// boundary is respected.  When no provider is available the method
+        /// falls back to <see cref="IAgentManager.GetCurrentAgentName"/> and
+        /// normalises a <see langword="null"/> return to
+        /// <see cref="string.Empty"/>.
+        /// </remarks>
+        /// <param name="agentManager">The agent manager to query.</param>
+        /// <returns>
+        /// The name of the active agent, or <see cref="string.Empty"/> when
+        /// no agent is currently active.
+        /// </returns>
+        public static string GetCurrentAgentNameViaQuery(this IAgentManager agentManager)
+        {
+            var handler = Context.ServiceProvider
+                ?.GetService(typeof(IQueryHandler<GetActiveAgentNameQuery, string>))
+                    as IQueryHandler<GetActiveAgentNameQuery, string>;
+
+            if (handler != null)
+            {
+                return handler.Handle(new GetActiveAgentNameQuery());
+            }
+
+            return agentManager.GetCurrentAgentName() ?? string.Empty;
+        }
+    }
+}