Refactor(API::DefaultAssistant): Move set and unset default assistant…

… logic from CreateAssistant to DefaultAssistantService within DefaultAssistant feature

src/Server/StellarChat.Server.Api/Extensions.cs

@@ -1,4 +1,6 @@
-namespace StellarChat.Server.Api;
+using StellarChat.Server.Api.Features.Assistants.DefaultAssistant;
+
+namespace StellarChat.Server.Api;
 
 internal static class Extensions
 {
@@ -13,6 +15,7 @@ public static void AddInfrastructure(this WebApplicationBuilder builder)
             .AddScoped<IChatMessageRepository, ChatMessageRepository>()
             .AddScoped<IChatSessionRepository, ChatSessionRepository>()
             .AddScoped<IAssistantRepository, AssistantRepository>()
+            .AddScoped<IDefaultAssistantService, DefaultAssistantService>()
             .AddMongoRepository<ChatMessageDocument, Guid>("messages")
             .AddMongoRepository<ChatSessionDocument, Guid>("chat-sessions")
             .AddMongoRepository<AssistantDocument, Guid>("assistants");

src/Server/StellarChat.Server.Api/Features/Assistants/DefaultAssistant/DefaultAssistantService.cs

@@ -0,0 +1,42 @@
+namespace StellarChat.Server.Api.Features.Assistants.DefaultAssistant;
+
+internal sealed class DefaultAssistantService : IDefaultAssistantService
+{
+    private readonly IAssistantRepository _assistantRepository;
+    private readonly TimeProvider _clock;
+    private readonly ILogger<DefaultAssistantService> _logger;
+
+    public DefaultAssistantService(IAssistantRepository assistantRepository, TimeProvider clock, ILogger<DefaultAssistantService> logger)
+    {
+        _assistantRepository = assistantRepository;
+        _clock = clock;
+        _logger = logger;
+    }
+
+    public async ValueTask SetDefaultAsync(Assistant assistant)
+    {
+        if (assistant is not null)
+        {
+            var now = _clock.GetUtcNow();
+
+            assistant.IsDefault = true;
+            assistant.UpdatedAt = now;
+            await _assistantRepository.UpdateAsync(assistant);
+
+            _logger.LogInformation($"Default assistant has been updated to new assistant with ID: {assistant.Id}");
+        }
+    }
+
+    public async ValueTask UnsetDefaultAsync()
+    {
+        var assistants = await _assistantRepository.BrowseAsync();
+        var currentDefaultAssistant = assistants.SingleOrDefault(assistant => assistant.IsDefault);
+
+        if (currentDefaultAssistant is not null)
+        {
+            currentDefaultAssistant.IsDefault = false;
+            await _assistantRepository.UpdateAsync(currentDefaultAssistant);
+            _logger.LogInformation($"Previous default assistant with ID: {currentDefaultAssistant.Id} has been unset.");
+        }
+    }
+}

src/Server/StellarChat.Server.Api/Features/Assistants/DefaultAssistant/IDefaultAssistantService.cs

@@ -0,0 +1,7 @@
+namespace StellarChat.Server.Api.Features.Assistants.DefaultAssistant;
+
+internal interface IDefaultAssistantService
+{
+    ValueTask UnsetDefaultAsync();
+    ValueTask SetDefaultAsync(Assistant assistant);
+}

src/Server/StellarChat.Server.Api/GlobalUsings.cs

@@ -21,6 +21,7 @@
 global using StellarChat.Server.Api.Domain.Assistants.Repositories;
 global using StellarChat.Server.Api.Domain.Chat.Models;
 global using StellarChat.Server.Api.Domain.Chat.Repositories;
+global using StellarChat.Server.Api.Features.Assistants.DefaultAssistant;
 global using StellarChat.Server.Api.Hubs;
 global using StellarChat.Shared.Abstractions.API.Endpoints;
 global using StellarChat.Shared.Abstractions.Exceptions;