#
# Copyright 2015 OpenStack Foundation
#
# 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_cache import core
from oslo_config import cfg

from heat.common.i18n import _

"""The module contains the code related to integration between oslo.cache
module and heat."""


def register_cache_configurations(conf):
    """Register all configurations required for oslo.cache

    The procedure registers all configurations required for oslo.cache.
    It should be called before configuring of cache region
    :param conf: instance of heat configuration
    :return updated heat configuration
    """
    # register global configurations for caching in heat
    core.configure(conf)

    # register heat specific configurations
    constraint_cache_group = cfg.OptGroup('constraint_validation_cache')
    constraint_cache_opts = [
        cfg.IntOpt('expiration_time', default=60,
                   help=_(
                       'TTL, in seconds, for any cached item in the '
                       'dogpile.cache region used for caching of validation '
                       'constraints.')),
        cfg.BoolOpt("caching", default=True,
                    help=_(
                        'Toggle to enable/disable caching when Orchestration '
                        'Engine validates property constraints of stack.'
                        'During property validation with constraints '
                        'Orchestration Engine caches requests to other '
                        'OpenStack services. Please note that the global '
                        'toggle for oslo.cache(enabled=True in [cache] group) '
                        'must be enabled to use this feature.'))
    ]
    conf.register_group(constraint_cache_group)
    conf.register_opts(constraint_cache_opts, group=constraint_cache_group)

    return conf


# variable that stores an initialized cache region for heat
_REGION = None


def get_cache_region():
    global _REGION
    if not _REGION:
        _REGION = core.configure_cache_region(
            conf=register_cache_configurations(cfg.CONF),
            region=core.create_region())
    return _REGION