Work in progress language selection support

Still need to add a popup telling you that NUSGet needs to be restarted after changing the language, and having it load the selected language in the selection menu so that it's checked on launch.

NUSGet.py

@@ -22,14 +22,16 @@ import sys
 import webbrowser
 from importlib.metadata import version
 
-from PySide6.QtGui import QIcon
+from PySide6.QtGui import QActionGroup, QIcon
 from PySide6.QtWidgets import QApplication, QMainWindow, QMessageBox, QFileDialog, QListView
-from PySide6.QtCore import QRunnable, Slot, QThreadPool, Signal, QObject, QLibraryInfo, QTranslator, QLocale
+from PySide6.QtCore import QRunnable, Slot, QThreadPool, Signal, QObject, QLibraryInfo
 
 from qt.py.ui_AboutDialog import AboutNUSGet
 from qt.py.ui_MainMenu import Ui_MainWindow
 
+from modules.config import *
 from modules.core import *
+from modules.language import *
 from modules.theme import is_dark_theme
 from modules.tree import NUSGetTreeModel, TIDFilterProxyModel
 from modules.download_batch import run_nus_download_batch
@@ -81,9 +83,6 @@ class MainWindow(QMainWindow, Ui_MainWindow):
         self.ui.download_btn.clicked.connect(self.download_btn_pressed)
         self.ui.script_btn.clicked.connect(self.script_btn_pressed)
         self.ui.custom_out_dir_btn.clicked.connect(self.choose_output_dir)
-        # About and About Qt Buttons
-        self.ui.actionAbout.triggered.connect(self.about_nusget)
-        self.ui.actionAbout_Qt.triggered.connect(lambda: QMessageBox.aboutQt(self))
         self.ui.pack_archive_checkbox.toggled.connect(
             lambda: connect_is_enabled_to_checkbox([self.ui.archive_file_entry], self.ui.pack_archive_checkbox))
         self.ui.custom_out_dir_checkbox.toggled.connect(
@@ -126,10 +125,26 @@ class MainWindow(QMainWindow, Ui_MainWindow):
         dropdown_delegate = ComboBoxItemDelegate()
         self.ui.console_select_dropdown.setItemDelegate(dropdown_delegate)
         self.ui.console_select_dropdown.currentIndexChanged.connect(self.selected_console_changed)
-        # Fix the annoying background on the help menu items.
-        self.ui.menuHelp.setWindowFlags(self.ui.menuHelp.windowFlags() | Qt.FramelessWindowHint)
-        self.ui.menuHelp.setWindowFlags(self.ui.menuHelp.windowFlags() | Qt.NoDropShadowWindowHint)
-        self.ui.menuHelp.setAttribute(Qt.WA_TranslucentBackground)
+        # ------------
+        # Options Menu
+        # ------------
+        # Fix the annoying background on the option menu items and submenus.
+        fixup_qmenu_background(self.ui.menu_options)
+        fixup_qmenu_background(self.ui.menu_options_language)
+        # Build a QActionGroup so that the language options function like radio buttons, because selecting multiple
+        # languages at once makes no sense.
+        language_group = QActionGroup(self)
+        language_group.setExclusive(True)
+        for action in self.ui.menu_options_language.actions():
+            language_group.addAction(action)
+        language_group.triggered.connect(lambda lang=action: set_language(config_data, lang.text()))
+        # ---------
+        # Help Menu
+        # ---------
+        # Same fix for help menu items.
+        fixup_qmenu_background(self.ui.menu_help)
+        self.ui.action_about.triggered.connect(self.about_nusget)
+        self.ui.action_about_qt.triggered.connect(lambda: QMessageBox.aboutQt(self))
         # Save some light/dark theme values for later, including the appropriately colored info icon.
         if is_dark_theme():
             bg_color = "#2b2b2b"
@@ -137,8 +152,8 @@ class MainWindow(QMainWindow, Ui_MainWindow):
         else:
             bg_color = "#e3e3e3"
             icon = QIcon(os.path.join(os.path.dirname(__file__), "resources", "information_black.svg"))
-        self.ui.actionAbout.setIcon(icon)
-        self.ui.actionAbout_Qt.setIcon(icon)
+        self.ui.action_about.setIcon(icon)
+        self.ui.action_about_qt.setIcon(icon)
         # Title tree loading code. Now powered by Models:tm:
         wii_model = NUSGetTreeModel(wii_database, root_name="Wii Titles")
         vwii_model = NUSGetTreeModel(vwii_database, root_name="vWii Titles")
@@ -683,16 +698,10 @@ if __name__ == "__main__":
     translator = QTranslator(app)
     if translator.load(QLocale.system(), 'qtbase', '_', path):
         app.installTranslator(translator)
-    translator = QTranslator(app)
+    # Get the translation path, and call get_language() to find the appropriate translations to load based on the
+    # settings and system language.
     path = os.path.join(os.path.dirname(__file__), "resources", "translations")
-    # Unix-likes and Windows handle this differently, apparently. Unix-likes will try `nusget_xx_XX.qm` and then fall
-    # back on just `nusget_xx.qm` if the region-specific translation for the language can't be found. On Windows, no
-    # such fallback exists, and so this code manually implements that fallback, since for languages like Spanish NUSGet
-    # doesn't use region-specific translations.
-    locale = QLocale.system()
-    if not translator.load(QLocale.system(), 'nusget', '_', path):
-        base_locale = QLocale(locale.language())
-        translator.load(base_locale, 'nusget', '_', path)
+    translator = get_language(QTranslator(app), config_data, path)
     app.installTranslator(translator)
 
     window = MainWindow()