# 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.

import functools

from oslo_config import cfg
from oslo_policy import policy

from armada.common import policies
from armada.exceptions import base_exception as exc

CONF = cfg.CONF
_ENFORCER = None


def reset_policy():
    global _ENFORCER
    if _ENFORCER:
        _ENFORCER.clear()
        _ENFORCER = None


def setup_policy():
    global _ENFORCER
    if not _ENFORCER:
        _ENFORCER = policy.Enforcer(CONF)
        register_rules(_ENFORCER)


def _enforce_policy(action, target, credentials, do_raise=True):
    extras = {}
    if do_raise:
        extras.update(exc=exc.ActionForbidden, do_raise=do_raise)

    _ENFORCER.enforce(action, target, credentials.to_policy_view(), **extras)


def enforce(rule):

    def decorator(func):

        @functools.wraps(func)
        def handler(*args, **kwargs):
            setup_policy()
            context = args[1].context
            _enforce_policy(rule, {}, context, do_raise=True)
            return func(*args, **kwargs)

        return handler

    return decorator


def register_rules(enforcer):
    enforcer.register_defaults(policies.list_rules())