[main] Fixed a bug with editing existing books

src/database/book_category_statistics.py

@@ -0,0 +1,9 @@
+from sqlalchemy.orm import Session
+from sqlalchemy import update
+
+from models import BookCategoryStatistics, Book
+
+def update_category_statistics(session: Session, book_id: int):
+    statistics = session.query(BookCategoryStatistics).get(book_id)
+
+    

src/ui/editor/book_editor.py

@@ -22,6 +22,7 @@ class BookEditor(QDialog):
         self.create_layout()
 
         if book:
+            self.book_id = book.id
             self.logger.debug(f"Editing existing book {book.title}")
             self.create_new = False
             self.fill_with_existing_data(book)
@@ -100,6 +101,7 @@ class BookEditor(QDialog):
             if self.create_new:
                 create_book(book_object)
             else:
+                book_object["id"] = self.book_id
                 update_book(book_object)
             
             QMessageBox.information(None,

src/utils/config.py

@@ -78,8 +78,10 @@ class UserConfig:
         return cls._instance
 
     def __init__(self):
-        self._transaction_level = TransactionLevel.insecure
-        self._simulate_slowdown = False
+        if not hasattr(self, "_transaction_level"):
+            self._transaction_level = TransactionLevel.insecure
+        if not hasattr(self, "_simulate_slowdown"):
+            self._simulate_slowdown = False
 
     @property
     def transaction_level(self) -> TransactionLevel: