#------------------------------------------------------------------------------
# Copyright (c) 2007, Riverbank Computing Limited
# All rights reserved.
#
# This software is provided without warranty under the terms of the BSD license.
# However, when used with the GPL version of PyQt the additional terms described in the PyQt GPL exception also apply

#------------------------------------------------------------------------------

# Major package imports.
from pyface.qt import QtGui

# Enthought library imports.
from traits.api import Any, Bool, HasTraits, List, Property, Str, \
    Unicode


class StatusBarManager(HasTraits):
    """ A status bar manager realizes itself in a status bar control. """

    # The message displayed in the first field of the status bar.
    message = Property

    # The messages to be displayed in the status bar fields.
    messages = List(Unicode)

    # The toolkit-specific control that represents the status bar.
    status_bar = Any

    # Whether to show a size grip on the status bar.
    size_grip = Bool(False)

    # Whether the status bar is visible.
    visible = Bool(True)

    ###########################################################################
    # 'StatusBarManager' interface.
    ###########################################################################

    def create_status_bar(self, parent):
        """ Creates a status bar. """

        if self.status_bar is None:
            self.status_bar = QtGui.QStatusBar(parent)
            self.status_bar.setSizeGripEnabled(self.size_grip)
            self.status_bar.setVisible(self.visible)

            if len(self.messages) > 1:
                self._show_messages()
            else:
                self.status_bar.showMessage(self.message)

        return self.status_bar

    def destroy_status_bar(self):
        """ Destroys the status bar. """
        if self.status_bar is not None:
            self.status_bar.deleteLater()
            self.status_bar = None

    ###########################################################################
    # Property handlers.
    ###########################################################################

    def _get_message(self):

        if len(self.messages) > 0:
            message = self.messages[0]
        else:
            message = ''

        return message

    def _set_message(self, value):

        if len(self.messages) > 0:
            old = self.messages[0]
            self.messages[0] = value
        else:
            old = ''
            self.messages.append(old)

        self.trait_property_changed('message', old, value)

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

    def _messages_changed(self):
        """ Sets the text displayed on the status bar. """

        if self.status_bar is not None:
            self._show_messages()

    def _messages_items_changed(self):
        """ Sets the text displayed on the status bar. """

        if self.status_bar is not None:
            self._show_messages()

    def _size_grip_changed(self):
        """ Turns the size grip on the status bar on and off. """

        if self.status_bar is not None:
            self.status_bar.setSizeGripEnabled(self.size_grip)

    def _visible_changed(self):
        """ Turns the status bar visibility on and off. """

        if self.status_bar is not None:
            self.status_bar.setVisible(self.visible)

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

    def _show_messages(self):
        """ Display the list of messages. """

        # FIXME v3: At the moment we just string them together but we may
        # decide to put all but the first message into separate widgets.  We
        # probably also need to extend the API to allow a "message" to be a
        # widget - depends on what wx is capable of.
        self.status_bar.showMessage("  ".join(self.messages))


#### EOF ######################################################################
