#
# Copyright 2013-2014 eNovance
#
# Author: Mehdi Abaakouk <mehdi.abaakouk@enovance.com>
#
# 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.
"""Rest alarm notifier."""

import eventlet
from oslo.config import cfg
from oslo.serialization import jsonutils
from oslo_context import context
import requests
import six.moves.urllib.parse as urlparse

from ceilometer.alarm import notifier
from ceilometer.i18n import _
from ceilometer.openstack.common import log

LOG = log.getLogger(__name__)

OPTS = [
    cfg.StrOpt('rest_notifier_certificate_file',
               default='',
               help='SSL Client certificate for REST notifier.'
               ),
    cfg.StrOpt('rest_notifier_certificate_key',
               default='',
               help='SSL Client private key for REST notifier.'
               ),
    cfg.BoolOpt('rest_notifier_ssl_verify',
                default=True,
                help='Whether to verify the SSL Server certificate when '
                'calling alarm action.'
                ),
    cfg.IntOpt('rest_notifier_max_retries',
               default=0,
               help='Number of retries for REST notifier',
               ),

]

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


class RestAlarmNotifier(notifier.AlarmNotifier):
    """Rest alarm notifier."""

    @staticmethod
    def notify(action, alarm_id, alarm_name, previous, current, reason,
               reason_data, headers=None):
        headers = headers or {}
        if not headers.get('x-openstack-request-id'):
            headers['x-openstack-request-id'] = context.generate_request_id()

        LOG.info(_(
            "Notifying alarm %(alarm_name)s %(alarm_id)s from "
            "%(previous)s to %(current)s with action %(action)s because "
            "%(reason)s. request-id: %(request_id)s ") %
            ({'alarm_name': alarm_name, 'alarm_id': alarm_id,
              'previous': previous, 'current': current,
              'action': action, 'reason': reason,
              'request_id': headers['x-openstack-request-id']}))
        body = {'alarm_name': alarm_name, 'alarm_id': alarm_id,
                'previous': previous, 'current': current,
                'reason': reason, 'reason_data': reason_data}
        headers['content-type'] = 'application/json'
        kwargs = {'data': jsonutils.dumps(body),
                  'headers': headers}

        if action.scheme == 'https':
            default_verify = int(cfg.CONF.alarm.rest_notifier_ssl_verify)
            options = urlparse.parse_qs(action.query)
            verify = bool(int(options.get('ceilometer-alarm-ssl-verify',
                                          [default_verify])[-1]))
            kwargs['verify'] = verify

            cert = cfg.CONF.alarm.rest_notifier_certificate_file
            key = cfg.CONF.alarm.rest_notifier_certificate_key
            if cert:
                kwargs['cert'] = (cert, key) if key else cert

        # FIXME(rhonjo): Retries are automatically done by urllib3 in requests
        # library. However, there's no interval between retries in urllib3
        # implementation. It will be better to put some interval between
        # retries (future work).
        max_retries = cfg.CONF.alarm.rest_notifier_max_retries
        session = requests.Session()
        session.mount(action.geturl(),
                      requests.adapters.HTTPAdapter(max_retries=max_retries))
        eventlet.spawn_n(session.post, action.geturl(), **kwargs)