#    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.

__all__ = [
    'list_opts',
    'set_defaults',
]

import copy

from oslo_config import cfg

from oslo_policy._i18n import _


_option_group = 'oslo_policy'

_options = [
    cfg.StrOpt('policy_file',
               default='policy.json',
               help=_('The file that defines policies.'),
               deprecated_group='DEFAULT'),
    cfg.StrOpt('policy_default_rule',
               default='default',
               help=_('Default rule. Enforced when a requested rule is not '
                      'found.'),
               deprecated_group='DEFAULT'),
    cfg.MultiStrOpt('policy_dirs',
                    default=['policy.d'],
                    help=_('Directories where policy configuration files are '
                           'stored. They can be relative to any directory '
                           'in the search path defined by the config_dir '
                           'option, or absolute paths. The file defined by '
                           'policy_file must exist for these directories to '
                           'be searched.  Missing or empty directories are '
                           'ignored.'),
                    deprecated_group='DEFAULT'),
]


def list_opts():
    """Return a list of oslo.config options available in the library.

    The returned list includes all oslo.config options which may be registered
    at runtime by the library.
    Each element of the list is a tuple. The first element is the name of the
    group under which the list of elements in the second element will be
    registered. A group name of None corresponds to the [DEFAULT] group in
    config files.
    This function is also discoverable via the 'oslo_messaging' entry point
    under the 'oslo.config.opts' namespace.
    The purpose of this is to allow tools like the Oslo sample config file
    generator to discover the options exposed to users by this library.

    :returns: a list of (group_name, opts) tuples
    """

    return [(_option_group, copy.deepcopy(_options))]


def _register(conf):
    """Register the policy options.

    We do this in a few places, so use a function to ensure it is done
    consistently.
    """
    conf.register_opts(_options, group=_option_group)


def set_defaults(conf, policy_file=None):
    """Set defaults for configuration variables.

    Overrides default options values.

    :param conf: Configuration object, managed by the caller.
    :type conf: oslo.config.cfg.ConfigOpts

    :param policy_file: The base filename for the file that
                        defines policies.
    :type policy_file: unicode
    """
    _register(conf)

    if policy_file is not None:
        conf.set_default('policy_file', policy_file, group=_option_group)