from automat import MethodicalMachine

class CoffeeBrewer(object):
    _machine = MethodicalMachine()
    @_machine.input()
    def brew_button(self):
        "The user pressed the 'brew' button."
    @_machine.output()
    def _heat_the_heating_element(self):
        "Heat up the heating element, which should cause coffee to happen."
        # self._heating_element.turn_on()
    @_machine.state()
    def have_beans(self):
        "In this state, you have some beans."
    @_machine.state(initial=True)
    def dont_have_beans(self):
        "In this state, you don't have any beans."
    @_machine.input()
    def put_in_beans(self, beans):
        "The user put in some beans."
    @_machine.output()
    def _save_beans(self, beans):
        "The beans are now in the machine; save them."
        self._beans = beans
    @_machine.output()
    def _describe_coffee(self):
        return "A cup of coffee made with {}.".format(self._beans)

    dont_have_beans.upon(put_in_beans, enter=have_beans,
                         outputs=[_save_beans])
    have_beans.upon(brew_button, enter=dont_have_beans,
                    outputs=[_heat_the_heating_element,
                             _describe_coffee],
                    collector=lambda iterable: list(iterable)[-1]
    )

cb = CoffeeBrewer()
cb.put_in_beans("real good beans")
print(cb.brew_button())