# Copyright (c) 2011 OpenStack Foundation
# 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.
#
# Copyright (c) 2022 Wind River Systems, Inc.
#
# SPDX-License-Identifier: Apache-2.0
#
"""Policy Engine For DC."""

from dcmanager.api import policies as controller_policies
from oslo_config import cfg
from oslo_policy import policy
from webob import exc


CONF = cfg.CONF
_ENFORCER = None


def reset():
    """Discard current Enforcer object."""
    global _ENFORCER
    _ENFORCER = None


def init(policy_file='policy.yaml'):
    """Init an Enforcer class.

       :param policy_file: Custom policy file to be used.

       :return: Returns a Enforcer instance.
    """
    global _ENFORCER
    if not _ENFORCER:

        # https://docs.openstack.org/oslo.policy/latest/user/usage.html
        _ENFORCER = policy.Enforcer(CONF,
                                    policy_file=policy_file,
                                    default_rule='default',
                                    use_conf=True,
                                    overwrite=True)
        _ENFORCER.register_defaults(controller_policies.list_rules())
    return _ENFORCER


def authorize(rule, target, creds, do_raise=True):
    """A wrapper around 'authorize' from 'oslo_policy.policy'."""
    init()
    return _ENFORCER.authorize(rule, target, creds, do_raise=do_raise,
                               exc=exc.HTTPForbidden)