from tkinter import Toplevel, TclError
import sys


class WindowList:

 def __init__(self):
 self.dict = {}
 self.callbacks = []

 def add(self, window):
 window.after_idle(self.call_callbacks)
 self.dict[str(window)] = window

 def delete(self, window):
 try:
 del self.dict[str(window)]
 except KeyError:
 # Sometimes, destroy() is called twice
 pass
 self.call_callbacks()

 def add_windows_to_menu(self, menu):
 list = []
 for key in self.dict:
 window = self.dict[key]
 try:
 title = window.get_title()
 except TclError:
 continue
 list.append((title, key, window))
 list.sort()
 for title, key, window in list:
 menu.add_command(label=title, command=window.wakeup)

 def register_callback(self, callback):
 self.callbacks.append(callback)

 def unregister_callback(self, callback):
 try:
 self.callbacks.remove(callback)
 except ValueError:
 pass

 def call_callbacks(self):
 for callback in self.callbacks:
 try:
 callback()
 except:
 t, v, tb = sys.exc_info()
 print("warning: callback failed in WindowList", t, ":", v)


registry = WindowList()

add_windows_to_menu = registry.add_windows_to_menu
register_callback = registry.register_callback
unregister_callback = registry.unregister_callback


class ListedToplevel(Toplevel):

 def __init__(self, master, **kw):
 Toplevel.__init__(self, master, kw)
 registry.add(self)
 self.focused_widget = self

 def destroy(self):
 registry.delete(self)
 Toplevel.destroy(self)
 # If this is Idle's last window then quit the mainloop
 # (Needed for clean exit on Windows 98)
 if not registry.dict:
 self.quit()

 def update_windowlist_registry(self, window):
 registry.call_callbacks()

 def get_title(self):
 # Subclass can override
 return self.wm_title()

 def wakeup(self):
 try:
 if self.wm_state() == "iconic":
 self.wm_withdraw()
 self.wm_deiconify()
 self.tkraise()
 self.focused_widget.focus_set()
 except TclError:
 # This can happen when the Window menu was torn off.
 # Simply ignore it.
 pass


if __name__ == "__main__":
 from unittest import main
 main('idlelib.idle_test.test_window', verbosity=2)