# (C) Copyright 2005-2022 Enthought, Inc., Austin, TX
# All rights reserved.
#
# This software is provided without warranty under the terms of the BSD
# license included in LICENSE.txt and may be redistributed only under
# the conditions described in the aforementioned license. The license
# is also available online at http://www.enthought.com/licenses/BSD.txt
#
# Thanks for using Enthought open source!

""" A wizard model that can be chained with other wizards. """


from traits.api import Instance, observe


from .i_wizard import IWizard
from .wizard import Wizard


class ChainedWizard(Wizard):
    """ A wizard model that can be chained with other wizards. """

    # 'ChainedWizard' interface --------------------------------------------

    # The wizard following this wizard in the chain.
    next_wizard = Instance(IWizard)

    # ------------------------------------------------------------------------
    # 'ChainedWizard' interface.
    # ------------------------------------------------------------------------

    # Trait handlers. -----------------------------------------------------#

    def _controller_default(self):
        """ Provide a default controller. """

        from .chained_wizard_controller import ChainedWizardController

        return ChainedWizardController()

    # Trait event handlers. ------------------------------------------------

    # Static ----

    @observe("next_wizard")
    def _reset_next_controller_and_update(self, event):
        """ Handle the next wizard being changed. """
        if event.new is not None:
            self.controller.next_controller = event.new.controller

        if self.control is not None:
            # FIXME: Do we need to call _create_buttons? Buttons would have
            # added when the main dialog area was created (for the first
            # wizard), and calling update should update the state of these
            # buttons. Do we need to check if buttons are already present in
            # the dialog area? What is use case for calling _create_buttons?
            # self._create_buttons(self.control)
            self._update()

    @observe("controller")
    def _reset_traits_on_controller_and_update(self, event):
        """ handle the controller being changed. """
        if event.new is not None and self.next_wizard is not None:
            self.controller.next_controller = self.next_wizard.controller

        if self.control is not None:
            self._update()

        return
