# This file is part of Buildbot.  Buildbot 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, version 2.
#
# This program 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, write to the Free Software Foundation, Inc., 51
# Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#
# Copyright Buildbot Team Members

from twisted.python import failure
from twisted.python import log


class SubscriptionPoint(object):

    def __init__(self, name):
        self.name = name
        self.subscriptions = set()

    def __str__(self):
        return "<SubscriptionPoint '%s'>" % self.name

    def subscribe(self, callback):
        sub = Subscription(self, callback)
        self.subscriptions.add(sub)
        return sub

    def deliver(self, *args, **kwargs):
        for sub in list(self.subscriptions):
            try:
                sub.callback(*args, **kwargs)
            except:
                log.err(failure.Failure(),
                        'while invoking callback %s to %s' % (sub.callback, self))

    def _unsubscribe(self, subscription):
        self.subscriptions.remove(subscription)


class Subscription(object):

    def __init__(self, subpt, callback):
        self.subpt = subpt
        self.callback = callback

    def unsubscribe(self):
        self.subpt._unsubscribe(self)
