fix: prevent potential component state updates after disposal and implement dedicated repository for quiz results

src/NexusReader.Application/Commands/Library/ProcessEbookCommand.cs

@@ -5,8 +5,8 @@ using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging;
 using NexusReader.Application.Abstractions.Messaging;
+using NexusReader.Application.Abstractions.Persistence;
 using NexusReader.Application.Abstractions.Services;
-using NexusReader.Data.Persistence;
 
 namespace NexusReader.Application.Commands.Library;
 
@@ -18,20 +18,20 @@ public record ProcessEbookCommand(
 
 public class ProcessEbookCommandHandler : IRequestHandler<ProcessEbookCommand, Result<bool>>
 {
-    private readonly IDbContextFactory<AppDbContext> _dbContextFactory;
+    private readonly IEbookRepository _ebookRepository;
     private readonly IKnowledgeService _knowledgeService;
     private readonly IEpubExtractor _epubExtractor;
     private readonly ISyncBroadcaster _broadcaster;
     private readonly ILogger<ProcessEbookCommandHandler> _logger;
 
     public ProcessEbookCommandHandler(
-        IDbContextFactory<AppDbContext> dbContextFactory,
+        IEbookRepository ebookRepository,
         IKnowledgeService knowledgeService,
         IEpubExtractor epubExtractor,
         ISyncBroadcaster broadcaster,
         ILogger<ProcessEbookCommandHandler> logger)
     {
-        _dbContextFactory = dbContextFactory;
+        _ebookRepository = ebookRepository;
         _knowledgeService = knowledgeService;
         _epubExtractor = epubExtractor;
         _broadcaster = broadcaster;
@@ -46,8 +46,7 @@ public class ProcessEbookCommandHandler : IRequestHandler<ProcessEbookCommand, R
         {
             await _broadcaster.BroadcastIngestionProgressAsync(request.UserId, "Wyszukiwanie e-booka w bazie danych...", 0.05, cancellationToken);
 
-            using var dbContext = await _dbContextFactory.CreateDbContextAsync(cancellationToken);
-            var ebook = await dbContext.Ebooks.FindAsync(new object[] { request.EbookId }, cancellationToken);
+            var ebook = await _ebookRepository.FindByIdAsync(request.EbookId, cancellationToken);
             if (ebook == null)
             {
                 _logger.LogError("[ProcessEbook] Ebook not found in database: {EbookId}", request.EbookId);
@@ -122,7 +121,7 @@ public class ProcessEbookCommandHandler : IRequestHandler<ProcessEbookCommand, R
 
             // Mark the ebook as ready
             ebook.IsReadyForReading = true;
-            await dbContext.SaveChangesAsync(cancellationToken);
+            await _ebookRepository.SaveChangesAsync(cancellationToken);
 
             _logger.LogInformation("[ProcessEbook] Ingestion and vector indexing completed for: {Title}", ebook.Title);