# -*- encoding: utf-8 -*-
#
# Copyright © 2012-2013 eNovance <licensing@enovance.com>
#
# Author: Julien Danjou <julien@danjou.info>
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.

from oslo.config import cfg
import oslo.messaging
from stevedore import extension

from ceilometer.event import converter as event_converter
from ceilometer import messaging
from ceilometer.openstack.common import context
from ceilometer.openstack.common.gettextutils import _  # noqa
from ceilometer.openstack.common import log
from ceilometer.openstack.common import service as os_service
from ceilometer import pipeline
from ceilometer import service
from ceilometer.storage import models


LOG = log.getLogger(__name__)


OPTS = [
    cfg.BoolOpt('ack_on_event_error',
                default=True,
                deprecated_group='collector',
                help='Acknowledge message when event persistence fails.'),
    cfg.BoolOpt('store_events',
                deprecated_group='collector',
                default=False,
                help='Save event details.'),
]

cfg.CONF.register_opts(OPTS, group="notification")


class NotificationService(service.DispatchedService, os_service.Service):

    NOTIFICATION_NAMESPACE = 'ceilometer.notification'

    def start(self):
        super(NotificationService, self).start()
        self.pipeline_manager = pipeline.setup_pipeline()

        self.notification_manager = extension.ExtensionManager(
            namespace=self.NOTIFICATION_NAMESPACE,
            invoke_on_load=True,
        )

        if not list(self.notification_manager):
            LOG.warning(_('Failed to load any notification handlers for %s'),
                        self.NOTIFICATION_NAMESPACE)

        ack_on_error = cfg.CONF.notification.ack_on_event_error

        targets = []
        for ext in self.notification_manager:
            handler = ext.obj
            LOG.debug(_('Event types from %(name)s: %(type)s'
                        ' (ack_on_error=%(error)s)') %
                      {'name': ext.name,
                       'type': ', '.join(handler.event_types),
                       'error': ack_on_error})
            targets.extend(handler.get_targets(cfg.CONF))

        self.listener = messaging.get_notification_listener(targets, self)

        LOG.debug(_('Loading event definitions'))
        self.event_converter = event_converter.setup_events(
            extension.ExtensionManager(
                namespace='ceilometer.event.trait_plugin'))

        self.listener.start()
        # Add a dummy thread to have wait() working
        self.tg.add_timer(604800, lambda: None)

    def stop(self):
        self.listener.stop()
        super(NotificationService, self).stop()

    def info(self, ctxt, publisher_id, event_type, payload, metadata):
        notification = messaging.convert_to_old_notification_format(
            'info', ctxt, publisher_id, event_type, payload, metadata)
        self.process_notification(notification)

    def process_notification(self, notification):
        """RPC endpoint for notification messages

        When another service sends a notification over the message
        bus, this method receives it. See _setup_subscription().

        """
        LOG.debug(_('notification %r'), notification.get('event_type'))
        self.notification_manager.map(self._process_notification_for_ext,
                                      notification=notification)

        if cfg.CONF.notification.store_events:
            return self._message_to_event(notification)
        else:
            return oslo.messaging.NotificationResult.HANDLED

    def _message_to_event(self, body):
        """Convert message to Ceilometer Event.

        NOTE: the rpc layer currently rips out the notification
        delivery_info, which is critical to determining the
        source of the notification. This will have to get added back later.

        """
        event = self.event_converter.to_event(body)

        if event is not None:
            LOG.debug(_('Saving event "%s"'), event.event_type)
            problem_events = []
            for dispatcher in self.dispatcher_manager:
                problem_events.extend(dispatcher.obj.record_events(event))
            if models.Event.UNKNOWN_PROBLEM in [x[0] for x in problem_events]:
                if not cfg.CONF.notification.ack_on_event_error:
                    return oslo.messaging.NotificationResult.REQUEUE
        return oslo.messaging.NotificationResult.HANDLED

    def _process_notification_for_ext(self, ext, notification):
        """Wrapper for calling pipelines when a notification arrives

        When a message is received by process_notification(), it calls
        this method with each notification plugin to allow all the
        plugins process the notification.

        """
        with self.pipeline_manager.publisher(context.get_admin_context()) as p:
            # FIXME(dhellmann): Spawn green thread?
            p(list(ext.obj.to_samples(notification)))