# (C) Copyright 2007-2021 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!
# Enthought library imports.
from pyface.action.api import Action, ActionItem, Group
from traits.api import Any, Instance, List, Property, Str, on_trait_change


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

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

    name = Property(Str, observe="window.active_task.name")
    style = "toggle"

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

    # The window to use for this action.
    window = Instance("envisage.ui.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.active_task:
            return self.window.active_task.name
        return ""

    @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 ####################################################

    id = "TaskWindowToggleGroup"
    items = List

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

    # The application that contains the group.
    application = Instance(
        "envisage.ui.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().destroy()
        if self.application:
            self.application.on_trait_change(
                self._rebuild, "window_opened, window_closed", 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 _application_default(self):
        return self.manager.controller.task.window.application

    def _items_default(self):
        self.application.on_trait_change(
            self._rebuild, "window_opened, window_closed"
        )
        return self._get_items()

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