Add Ollama AI foundation for article 6.1

TalentManagementAPI.Application/Interfaces/IAiChatService.cs

@@ -0,0 +1,7 @@
+namespace TalentManagementAPI.Application.Interfaces
+{
+    public interface IAiChatService
+    {
+        Task<string> ChatAsync(string message, string? systemPrompt = null, CancellationToken cancellationToken = default);
+    }
+}

TalentManagementAPI.Infrastructure.Shared/GlobalUsings.cs

@@ -1,6 +1,7 @@
 global using System;
 global using System.Collections.Generic;
 global using System.Linq;
+global using System.Threading;
 global using System.Threading.Tasks;
 global using AutoBogus;
 global using Bogus;
@@ -12,6 +13,8 @@
 global using Microsoft.Extensions.Logging;
 global using Microsoft.Extensions.Options;
 global using MimeKit;
+global using OllamaSharp;
+global using OllamaSharp.Models.Chat;
 global using TalentManagementAPI.Application.DTOs.Email;
 global using TalentManagementAPI.Application.Exceptions;
 global using TalentManagementAPI.Application.Interfaces;

TalentManagementAPI.Infrastructure.Shared/ServiceRegistration.cs

@@ -1,13 +1,23 @@
-namespace TalentManagementAPI.Infrastructure.Shared
+using TalentManagementAPI.Application.Interfaces;
+using TalentManagementAPI.Infrastructure.Shared.Services;
+
+namespace TalentManagementAPI.Infrastructure.Shared
 {
     public static class ServiceRegistration
     {
-        public static void AddSharedInfrastructure(this IServiceCollection services, IConfiguration _config)
+        public static void AddSharedInfrastructure(this IServiceCollection services, IConfiguration config)
         {
-            services.Configure<MailSettings>(_config.GetSection("MailSettings"));
+            services.Configure<MailSettings>(config.GetSection("MailSettings"));
             services.AddTransient<IDateTimeService, DateTimeService>();
             services.AddTransient<IEmailService, EmailService>();
             services.AddTransient<IMockService, MockService>();
+            services.AddSingleton<IOllamaApiClient>(_ =>
+            {
+                var baseUrl = config["Ollama:BaseUrl"] ?? "http://localhost:11434";
+                var model = config["Ollama:Model"] ?? "llama3.2";
+                return new OllamaApiClient(new Uri(baseUrl), model);
+            });
+            services.AddTransient<IAiChatService, OllamaAiService>();
         }
     }
 }

TalentManagementAPI.Infrastructure.Shared/Services/OllamaAiService.cs

@@ -0,0 +1,45 @@
+using TalentManagementAPI.Application.Interfaces;
+
+namespace TalentManagementAPI.Infrastructure.Shared.Services
+{
+    public class OllamaAiService : IAiChatService
+    {
+        private readonly IOllamaApiClient _ollamaApiClient;
+
+        public OllamaAiService(IOllamaApiClient ollamaApiClient)
+        {
+            _ollamaApiClient = ollamaApiClient;
+        }
+
+        public async Task<string> ChatAsync(string message, string? systemPrompt = null, CancellationToken cancellationToken = default)
+        {
+            var messages = new List<Message>();
+
+            if (!string.IsNullOrWhiteSpace(systemPrompt))
+            {
+                messages.Add(new Message(new ChatRole("system"), systemPrompt));
+            }
+
+            messages.Add(new Message(new ChatRole("user"), message));
+
+            var request = new ChatRequest
+            {
+                Model = _ollamaApiClient.SelectedModel,
+                Messages = messages,
+                Stream = true
+            };
+
+            var responseBuilder = new MessageBuilder();
+
+            await foreach (var response in _ollamaApiClient.ChatAsync(request, cancellationToken).WithCancellation(cancellationToken))
+            {
+                if (response?.Message is not null)
+                {
+                    responseBuilder.Append(response);
+                }
+            }
+
+            return responseBuilder.HasValue ? responseBuilder.ToMessage().Content ?? string.Empty : string.Empty;
+        }
+    }
+}

TalentManagementAPI.Infrastructure.Shared/TalentManagementAPI.Infrastructure.Shared.csproj

@@ -9,10 +9,11 @@
   <ItemGroup>
     <PackageReference Include="AutoBogus" Version="2.13.1" />
     <PackageReference Include="Bogus" Version="35.6.5" />
-    <PackageReference Include="MailKit" Version="4.14.1" />
-    <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="10.0.2" />
-    <PackageReference Include="Microsoft.Extensions.Options.ConfigurationExtensions" Version="10.0.1" />
-    <PackageReference Include="MimeKit" Version="4.14.0" />
+    <PackageReference Include="MailKit" Version="4.15.1" />
+    <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="10.0.5" />
+    <PackageReference Include="Microsoft.Extensions.Options.ConfigurationExtensions" Version="10.0.5" />
+    <PackageReference Include="MimeKit" Version="4.15.1" />
+    <PackageReference Include="OllamaSharp" Version="5.4.23" />
   </ItemGroup>
 
   <ItemGroup>

TalentManagementAPI.WebApi/Controllers/v1/AiController.cs

@@ -0,0 +1,38 @@
+using Asp.Versioning;
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.FeatureManagement.Mvc;
+using TalentManagementAPI.Application.Interfaces;
+
+namespace TalentManagementAPI.WebApi.Controllers.v1
+{
+    [FeatureGate("AiEnabled")]
+    [ApiVersion("1.0")]
+    [AllowAnonymous]
+    [Route("api/v{version:apiVersion}/ai")]
+    public sealed class AiController : BaseApiController
+    {
+        private readonly IAiChatService _aiChatService;
+
+        public AiController(IAiChatService aiChatService)
+        {
+            _aiChatService = aiChatService;
+        }
+
+        /// <summary>
+        /// Send a message to the AI assistant and receive a reply.
+        /// </summary>
+        /// <param name="request">The chat message and optional system prompt.</param>
+        /// <param name="cancellationToken">Cancellation token.</param>
+        /// <returns>The AI-generated reply.</returns>
+        [HttpPost("chat")]
+        public async Task<IActionResult> Chat([FromBody] AiChatRequest request, CancellationToken cancellationToken)
+        {
+            var reply = await _aiChatService.ChatAsync(request.Message, request.SystemPrompt, cancellationToken);
+            return Ok(new AiChatResponse(reply));
+        }
+    }
+
+    public record AiChatRequest(string Message, string? SystemPrompt = null);
+    public record AiChatResponse(string Reply);
+}

TalentManagementAPI.WebApi/Program.cs

@@ -19,6 +19,8 @@
     builder.Services.AddApplicationLayer();
     builder.Services.AddPersistenceInfrastructure(builder.Configuration);
     builder.Services.AddSharedInfrastructure(builder.Configuration);
+    // Register Ollama chat client (IChatClient) — used by OllamaAiService
+    // AiController is gated by [FeatureGate("AiEnabled")], so no calls are made when AI is disabled
     builder.Services.AddEasyCachingInfrastructure(builder.Configuration);
     builder.Services.AddHttpContextAccessor();
     builder.Services.AddScoped<ICacheDiagnosticsPublisher, HttpCacheDiagnosticsPublisher>();

TalentManagementAPI.WebApi/appsettings.json

@@ -106,7 +106,12 @@
     "ExecutionTimingIncludeHeader": true,
     "ExecutionTimingIncludePayload": true,
     "ExecutionTimingLogTimings": false,
-    "UseInMemoryDatabase": false
+    "UseInMemoryDatabase": false,
+    "AiEnabled": false
+  },
+  "Ollama": {
+    "BaseUrl": "http://localhost:11434",
+    "Model": "llama3.2"
   },
   "ApiRoles": {
     "EmployeeRole": "Employee",