# -*- coding: utf-8 -*-
#
# gPodder - A media aggregator and podcast client
# Copyright (c) 2005-2018 The gPodder Team
#
# gPodder is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# gPodder is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#


#
#  services.py -- Core Services for gPodder
#  Thomas Perl <thp@perli.net>   2007-08-24
#
#

import gpodder
from gpodder import util

_ = gpodder.gettext


class ObservableService(object):
    def __init__(self, signal_names=[]):
        self.observers = {}
        for signal in signal_names:
            self.observers[signal] = []

    def register(self, signal_name, observer):
        if signal_name in self.observers:
            if observer not in self.observers[signal_name]:
                self.observers[signal_name].append(observer)
                return True

        return False

    def unregister(self, signal_name, observer):
        if signal_name in self.observers:
            if observer in self.observers[signal_name]:
                self.observers[signal_name].remove(observer)
                return True

        return False

    def notify(self, signal_name, *args):
        if signal_name in self.observers:
            for observer in self.observers[signal_name]:
                util.idle_add(observer, *args)

            return True

        return False