Refactoring and comments (#3721)

Author: YukiNagat0

qt/aqt/main.py

@@ -800,15 +800,20 @@ def _overviewState(self, oldState: MainWindowState) -> None:
     def _reviewState(self, oldState: MainWindowState) -> None:
         self.reviewer.show()
 
-        if self.fullscreen:
-            self.hide_menubar()
+        fullscreen_was_checked = False
 
         if self.pm.hide_top_bar():
             self.toolbarWeb.hide_timer.setInterval(500)
             self.toolbarWeb.hide_timer.start()
+
+            # check the `hide_if_allowed` method in `qt/aqt/toolbar.py`
+            fullscreen_was_checked = True
         else:
             self.toolbarWeb.flatten()
 
+        if not fullscreen_was_checked and self.fullscreen:
+            self.hide_menubar()
+
         if self.pm.hide_bottom_bar():
             self.bottomWeb.hide_timer.setInterval(500)
             self.bottomWeb.hide_timer.start()

qt/aqt/toolbar.py

@@ -98,6 +98,9 @@ def hide_if_allowed(self) -> None:
         if self.mw.state != "review":
             return
 
+        # Invariant: The `hide_if_allowed` method ensures that the fullscreen state is checked
+        # and the menubar will be hidden if necessary
+        # Note: The `eventFilter` and `_reviewState` methods in `qt/aqt/main.py` rely on this invariant
         if self.mw.fullscreen:
             self.mw.hide_menubar()