#
# Copyright 2012 New Dream Network, LLC (DreamHost)
#
# Author: Doug Hellmann <doug.hellmann@dreamhost.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.
"""Base class for plugins used by the central agent.
"""
from keystoneclient.v2_0 import client as ksclient
from oslo.config import cfg

from ceilometer.openstack.common.gettextutils import _
from ceilometer.openstack.common import log
from ceilometer import plugin

cfg.CONF.import_opt('http_timeout', 'ceilometer.service')
cfg.CONF.import_group('service_credentials', 'ceilometer.service')

LOG = log.getLogger(__name__)


class CentralPollster(plugin.PollsterBase):
    """Base class for plugins that support the polling API."""


def _get_keystone():
    try:
        return ksclient.Client(
            username=cfg.CONF.service_credentials.os_username,
            password=cfg.CONF.service_credentials.os_password,
            tenant_id=cfg.CONF.service_credentials.os_tenant_id,
            tenant_name=cfg.CONF.service_credentials.os_tenant_name,
            cacert=cfg.CONF.service_credentials.os_cacert,
            auth_url=cfg.CONF.service_credentials.os_auth_url,
            region_name=cfg.CONF.service_credentials.os_region_name,
            insecure=cfg.CONF.service_credentials.insecure,
            timeout=cfg.CONF.http_timeout)
    except Exception as e:
        return e


def check_keystone(service_type=None):
    """Decorator function to check if manager has valid keystone client.

       Also checks if the service is registered/enabled in Keystone.

       :param service_type: name of service in Keystone
    """
    def wrapped(f):
        def func(self, *args, **kwargs):
            manager = kwargs.get('manager')
            if not manager and len(args) > 0:
                manager = args[0]
            keystone = getattr(manager, 'keystone', None)
            if not keystone:
                keystone = _get_keystone()
            if isinstance(keystone, Exception):
                LOG.error(_('Skip due to keystone error %s'),
                          str(keystone) if keystone else '')
                return iter([])
            elif service_type:
                endpoints = keystone.service_catalog.get_endpoints(
                    service_type=service_type)
                if not endpoints:
                    LOG.warning(_('Skipping because %s service is not '
                                  'registered in keystone') % service_type)
                    return iter([])
            return f(self, *args, **kwargs)
        return func
    return wrapped