feat: prevent selection of suffix text in preferences spinboxes

CONTRIBUTORS

@@ -214,6 +214,7 @@ Mike Hardy <[email protected]>
 Danika_Dakika <https://github.com/Danika-Dakika>
 Mumtaz Hajjo Alrifai <[email protected]>
 Jakub Fidler <[email protected]>
+Adnane Taghi <[email protected]>
 
 ********************
 

qt/aqt/about.py

@@ -217,6 +217,7 @@ def on_dialog_destroyed() -> None:
             "Mumtaz Hajjo Alrifai",
             "Luc Mcgrady",
             "Brayan Oliveira",
+            "Adnane Taghi",
         )
     )
 

qt/aqt/preferences.py

@@ -47,6 +47,37 @@ def __init__(self, mw: AnkiQt) -> None:
         ):
             spinbox.setSuffix(f" {spinbox.suffix()}")
 
+            # Prevent selecting spinboxes' suffixes or placing the cursor after them
+            class UnitSpinBoxEventFilter(QObject):
+                def eventFilter(
+                    self, spinbox: QObject | None, evt: QEvent | None
+                ) -> bool:
+                    if not isinstance(spinbox, QSpinBox) or not isinstance(evt, QEvent):
+                        return False
+                    # maximum position of the cursor
+                    posAfterValue = len(str(spinbox.value()))
+                    lineEdit = spinbox.lineEdit()
+                    if lineEdit is None:
+                        return False
+                    if (
+                        evt.type() == QEvent.Type.InputMethodQuery
+                        and lineEdit.cursorPosition() > posAfterValue
+                    ):
+                        if lineEdit.hasSelectedText():
+                            absoluteSelectionEnd = (
+                                lineEdit.selectionStart() + lineEdit.selectionLength()
+                            )
+                            if absoluteSelectionEnd > posAfterValue:
+                                lineEdit.setSelection(
+                                    lineEdit.selectionStart(),
+                                    posAfterValue - lineEdit.selectionStart(),
+                                )
+                        else:
+                            lineEdit.setCursorPosition(posAfterValue)
+                    return False
+
+            spinbox.installEventFilter(UnitSpinBoxEventFilter(mw))
+
         disable_help_button(self)
         help_button = self.form.buttonBox.button(QDialogButtonBox.StandardButton.Help)
         assert help_button is not None