import patterns
import mywidgets
import time

class HelloFunctor(object):
    def __call__(self, observer):
        if observer.Subject.text == 'Hello World':
            observer.Subject.text = 'Goodbye World'
        else:
            observer.Subject.text = 'Hello World'

class QuitFunctor(object):
    def __init__(self):
        self.done = False
    def __call__(self, observer):
        self.done = True

factory = mywidgets.TkWidgetFactory()
hello_button = factory.button(text='Hello World')
quit_button = factory.button(text='Quit')
factory.window().contents = [
        hello_button,
        '\n',
        quit_button,
    ]

quit = QuitFunctor()
patterns.CallbackObserver(hello_button, HelloFunctor())
patterns.CallbackObserver(quit_button, quit)

while not quit.done:
    time.sleep(.1)

factory.do_quit() # FIXME: this seems out of place