qwen edit

BookReader/ViewModels/ReaderViewModel.cs

@@ -90,6 +90,20 @@ public partial class ReaderViewModel : BaseViewModel
 
     public async Task InitializeAsync()
     {
+        // Валидация: книга должна быть загружена
+        if (Book == null)
+        {
+            System.Diagnostics.Debug.WriteLine("[ReaderViewModel] Book is null, cannot initialize");
+            return;
+        }
+
+        // Валидация: файл книги должен существовать
+        if (!File.Exists(Book.FilePath))
+        {
+            System.Diagnostics.Debug.WriteLine($"[ReaderViewModel] Book file not found: {Book.FilePath}");
+            return;
+        }
+
         var savedFontSize = await _settingsService.GetIntAsync(SettingsKeys.DefaultFontSize, 18);
         var savedFontFamily = await _settingsService.GetAsync(SettingsKeys.DefaultFontFamily, "serif");
 
@@ -145,15 +159,22 @@ public partial class ReaderViewModel : BaseViewModel
 
     public async Task SaveLocationsAsync(string locations)
     {
-        if (Book == null) return;
+        if (Book == null)
+        {
+            System.Diagnostics.Debug.WriteLine("[ReaderViewModel] Cannot save locations: Book is null");
+            return;
+        }
         Book.Locations = locations;
-        // Сохраняем в базу данных
         await _databaseService.UpdateBookAsync(Book);
     }
 
     public async Task SaveProgressAsync(double progress, string? cfi, string? chapter, int currentPage, int totalPages)
     {
-        if (Book == null) return;
+        if (Book == null)
+        {
+            System.Diagnostics.Debug.WriteLine("[ReaderViewModel] Cannot save progress: Book is null");
+            return;
+        }
 
         // Важно: если CFI пустой, не перезаписываем старый прогресс (защита от багов JS)
         if (string.IsNullOrEmpty(cfi) && progress <= 0) return;
@@ -165,7 +186,6 @@ public partial class ReaderViewModel : BaseViewModel
         Book.TotalPages = totalPages;
         Book.LastRead = DateTime.UtcNow;
 
-        // Сохраняем в базу данных
         await _databaseService.UpdateBookAsync(Book);
 
         await _databaseService.SaveProgressAsync(new ReadingProgress