# 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.

"""Policy Engine For Ironic."""

import os.path

from oslo.config import cfg

from ironic.common import exception
from ironic.common import utils
from ironic.openstack.common.gettextutils import _
from ironic.openstack.common import policy


policy_opts = [
    cfg.StrOpt('policy_file',
               default='policy.json',
               help=_('JSON file representing policy.')),
    cfg.StrOpt('policy_default_rule',
               default='default',
               help=_('Rule checked when requested rule is not found.')),
    ]

CONF = cfg.CONF
CONF.register_opts(policy_opts)

_POLICY_PATH = None
_POLICY_CACHE = {}


def reset():
    global _POLICY_PATH
    global _POLICY_CACHE
    _POLICY_PATH = None
    _POLICY_CACHE = {}
    policy.reset()


def init():
    global _POLICY_PATH
    global _POLICY_CACHE
    if not _POLICY_PATH:
        _POLICY_PATH = CONF.policy_file
        if not os.path.exists(_POLICY_PATH):
            _POLICY_PATH = CONF.find_file(_POLICY_PATH)
        if not _POLICY_PATH:
            raise exception.ConfigNotFound(path=CONF.policy_file)
    utils.read_cached_file(_POLICY_PATH, _POLICY_CACHE,
                           reload_func=_set_rules)


def _set_rules(data):
    default_rule = CONF.policy_default_rule
    policy.set_rules(policy.Rules.load_json(data, default_rule))
