# Copyright (c) 2015 The Johns Hopkins University/Applied Physics Laboratory
# All Rights Reserved.
#
#    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
from oslo_log import log as logging
from oslo_utils import importutils
from stevedore import driver
from stevedore import exception

LOG = logging.getLogger(__name__)

key_manager_opts = [
    cfg.StrOpt('backend',
               default='barbican',
               deprecated_name='api_class',
               deprecated_group='key_manager',
               help='Specify the key manager implementation. Options are '
                    '"barbican" and "vault". Default is  "barbican". Will '
                    'support the  values earlier set using '
                    '[key_manager]/api_class for some time.'),
]


def API(configuration=None):
    conf = configuration or cfg.CONF
    conf.register_opts(key_manager_opts, group='key_manager')

    try:
        mgr = driver.DriverManager("castellan.drivers",
                                   conf.key_manager.backend,
                                   invoke_on_load=True,
                                   invoke_args=[conf])
        return mgr.driver
    except exception.NoMatches:
        LOG.warning("Deprecation Warning : %s is not a stevedore based driver,"
                    " trying to load it as a class", conf.key_manager.backend)
        cls = importutils.import_class(conf.key_manager.backend)
        return cls(configuration=conf)