import gi

gi.require_version("Gtk", "4.0")
from gi.repository import Gtk, Gio


class MyWindow(Gtk.ApplicationWindow):
    def __init__(self, app):
        super().__init__(application=app)
        self.set_default_size(400, 300)

        # Create actions
        file_new_action = Gio.SimpleAction.new("new", None)
        file_new_action.connect("activate", self.on_file_new)
        self.add_action(file_new_action)

        file_quit_action = Gio.SimpleAction.new("quit", None)
        file_quit_action.connect("activate", self.on_file_quit)
        self.add_action(file_quit_action)

        # Create menu model
        menu_model = Gio.Menu()
        file_menu = Gio.Menu()
        file_menu.append("New", "win.new")
        file_menu.append("Quit", "win.quit")
        menu_model.append_submenu("File", file_menu)

        # Create a menubar
        menubar = Gtk.MenuBar()
        menubar.set_menu_model(menu_model)
        self.set_titlebar(menubar)

    def on_file_new(self, action, param):
        print("New file")

    def on_file_quit(self, action, param):
        self.get_application().quit()


class MyApp(Gtk.Application):
    def __init__(self):
        super().__init__(application_id="com.example.GtkApp")

    def do_activate(self):
        window = MyWindow(self)
        window.present()

    def do_startup(self):
        Gtk.Application.do_startup(self)


if __name__ == "__main__":
    app = MyApp()
    app.run(None)