[FA-4] Adds an event bus infrastructure, a RabbitMQ implementation and rewires existing mutations on NovelService to utilize it.

FictionArchive.Service.TranslationService/Services/EventHandlers/TranslationRequestCreatedEventHandler.cs

@@ -0,0 +1,31 @@
+using FictionArchive.Service.Shared.Services.EventBus;
+using FictionArchive.Service.TranslationService.Models.Enums;
+using FictionArchive.Service.TranslationService.Models.IntegrationEvents;
+
+namespace FictionArchive.Service.TranslationService.Services.EventHandlers;
+
+public class TranslationRequestCreatedEventHandler : IIntegrationEventHandler<TranslationRequestCreatedEvent>
+{
+    private readonly ILogger<TranslationRequestCreatedEventHandler> _logger;
+    private readonly TranslationEngineService _translationEngineService;
+    private readonly IEventBus _eventBus;
+
+    public TranslationRequestCreatedEventHandler(ILogger<TranslationRequestCreatedEventHandler> logger, TranslationEngineService translationEngineService)
+    {
+        _logger = logger;
+        _translationEngineService = translationEngineService;
+    }
+
+    public async Task Handle(TranslationRequestCreatedEvent @event)
+    {
+        var result = await _translationEngineService.Translate(@event.From, @event.To, @event.Body, @event.TranslationEngineKey);
+        if (result.Status == TranslationRequestStatus.Success)
+        {
+            await _eventBus.Publish(new TranslationRequestCompletedEvent()
+            {
+                TranslatedText = result.TranslatedText,
+                TranslationRequestId = @event.TranslationRequestId,
+            });
+        }
+    }
+}

FictionArchive.Service.TranslationService/Services/TranslationEngineService.cs

@@ -0,0 +1,47 @@
+using System.Text;
+using FictionArchive.Common.Enums;
+using FictionArchive.Service.Shared.Services.EventBus;
+using FictionArchive.Service.Shared.Services.EventBus.Implementations;
+using FictionArchive.Service.TranslationService.Models;
+using FictionArchive.Service.TranslationService.Models.Database;
+using FictionArchive.Service.TranslationService.Models.Enums;
+using FictionArchive.Service.TranslationService.Models.IntegrationEvents;
+using FictionArchive.Service.TranslationService.Services.Database;
+using FictionArchive.Service.TranslationService.Services.TranslationEngines;
+using RabbitMQ.Client;
+
+namespace FictionArchive.Service.TranslationService.Services;
+
+public class TranslationEngineService
+{
+    private readonly IEnumerable<ITranslationEngine> _translationEngines;
+    private readonly IEventBus _eventBus;
+    private readonly TranslationServiceDbContext _dbContext;
+
+    public TranslationEngineService(IEnumerable<ITranslationEngine> translationEngines, TranslationServiceDbContext dbContext, IEventBus eventBus)
+    {
+        _translationEngines = translationEngines;
+        _dbContext = dbContext;
+        _eventBus = eventBus;
+    }
+
+    public async Task<TranslationResult> Translate(Language from, Language to, string text, string translationEngineKey)
+    {
+        var engine = _translationEngines.FirstOrDefault(engine => engine.Descriptor.Key == translationEngineKey);
+        var translation = await engine.GetTranslation(text, from, to);
+
+        _dbContext.TranslationRequests.Add(new TranslationRequest()
+        {
+            OriginalText = text,
+            BilledCharacterCount = translation.BilledCharacterCount, // FILL ME
+            From = from,
+            To = to,
+            Status = translation != null ? TranslationRequestStatus.Success : TranslationRequestStatus.Failed,
+            TranslatedText = translation.TranslatedText,
+            TranslationEngineKey = translationEngineKey
+        });
+        await _dbContext.SaveChangesAsync();
+        
+        return translation;
+    }
+}

FictionArchive.Service.TranslationService/Services/TranslationEngines/DeepLTranslate/DeepLTranslationEngine.cs

@@ -1,6 +1,7 @@
 using DeepL;
 using DeepL.Model;
 using FictionArchive.Service.TranslationService.Models;
+using FictionArchive.Service.TranslationService.Models.Enums;
 using Language = FictionArchive.Common.Enums.Language;
 
 namespace FictionArchive.Service.TranslationService.Services.TranslationEngines.DeepLTranslate;
@@ -31,11 +32,20 @@ public class DeepLTranslationEngine : ITranslationEngine
         }
     }
 
-    public async Task<string?> GetTranslation(string body, Language from, Language to)
+    public async Task<TranslationResult> GetTranslation(string body, Language from, Language to)
     {
         TextResult translationResult = await _deepLClient.TranslateTextAsync(body, GetLanguageCode(from), GetLanguageCode(to));
         _logger.LogInformation("Translated text. Usage statistics: CHARACTERS BILLED {TranslationResultBilledCharacters}", translationResult.BilledCharacters);
-        return translationResult.Text;
+        return new TranslationResult()
+        {
+            OriginalText = body,
+            From = from,
+            To = to,
+            TranslationEngineKey = Key,
+            BilledCharacterCount = (uint)translationResult.BilledCharacters,
+            Status = TranslationRequestStatus.Success,
+            TranslatedText = translationResult.Text
+        };
     }
 
     private string GetLanguageCode(Language language)

FictionArchive.Service.TranslationService/Services/TranslationEngines/ITranslationEngine.cs

@@ -6,5 +6,5 @@ namespace FictionArchive.Service.TranslationService.Services.TranslationEngines;
 public interface ITranslationEngine
 {
     public TranslationEngineDescriptor Descriptor { get; }
-    public Task<string?> GetTranslation(string body, Language from, Language to);
+    public Task<TranslationResult> GetTranslation(string body, Language from, Language to);
 }