# Copyright (c) 2010-18, Enthought, Inc.
# All rights reserved.
#
# This software is provided without warranty under the terms of the BSD
# license included in enthought/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!

# Enthought library imports.
from pyface.action.api import Action, ActionItem, Group
from traits.api import Any, Instance, List, Property, Unicode, on_trait_change


class TaskWindowToggleAction(Action):
    """ An action for activating an application window.
    """

    # 'Action' interface -----------------------------------------------------

    #: The name of the action for the window.
    name = Property(Unicode, depends_on='window.title')

    #: The action is a toggle action.
    style = 'toggle'

    # 'TaskWindowToggleAction' interface -------------------------------------

    # The window to use for this action.
    window = Instance('pyface.tasks.task_window.TaskWindow')

    # -------------------------------------------------------------------------
    # 'Action' interface.
    # -------------------------------------------------------------------------

    def perform(self, event=None):
        if self.window:
            self.window.activate()

    # -------------------------------------------------------------------------
    # Private interface.
    # -------------------------------------------------------------------------

    def _get_name(self):
        if self.window.title:
            return self.window.title
        return u''

    @on_trait_change('window:activated')
    def _window_activated(self):
        self.checked = True

    @on_trait_change('window:deactivated')
    def _window_deactivated(self):
        self.checked = False


class TaskWindowToggleGroup(Group):
    """ A Group for toggling the activation state of an application's windows.
    """

    # 'Group' interface ------------------------------------------------------

    #: The id of the action group.
    id = 'TaskWindowToggleGroup'

    #: The actions in the action group
    items = List

    # 'TaskWindowToggleGroup' interface --------------------------------------

    #: The application that contains the group.
    application = Instance('pyface.tasks.tasks_application.TasksApplication')

    #: The ActionManager to which the group belongs.
    manager = Any

    # -------------------------------------------------------------------------
    # 'Group' interface.
    # -------------------------------------------------------------------------

    def destroy(self):
        """ Called when the group is no longer required.
        """
        super(TaskWindowToggleGroup, self).destroy()
        if self.application:
            self.application.on_trait_change(
                self._rebuild, 'windows[]', remove=True
            )

    # -------------------------------------------------------------------------
    # Private interface.
    # -------------------------------------------------------------------------

    def _get_items(self):
        items = []
        for window in self.application.windows:
            active = window == self.application.active_window
            action = TaskWindowToggleAction(window=window, checked=active)
            items.append(ActionItem(action=action))
        return items

    def _rebuild(self):
        # Clear out the old group, then build the new one.
        for item in self.items:
            item.destroy()
        self.items = self._get_items()

        # Inform our manager that it needs to be rebuilt.
        self.manager.changed = True

    # Trait initializers -----------------------------------------------------

    def _items_default(self):
        self.application.on_trait_change(self._rebuild, 'windows[]')
        return self._get_items()

    def _manager_default(self):
        manager = self
        while isinstance(manager, Group):
            manager = manager.parent
        return manager