# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements.  See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership.  The ASF licenses this file
# to you 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 copy import deepcopy


class FeatureFlagManager:
    def __init__(self) -> None:
        super().__init__()
        self._get_feature_flags_func = None
        self._feature_flags = None

    def init_app(self, app):
        self._get_feature_flags_func = app.config.get("GET_FEATURE_FLAGS_FUNC")
        self._feature_flags = app.config.get("DEFAULT_FEATURE_FLAGS") or {}
        self._feature_flags.update(app.config.get("FEATURE_FLAGS") or {})

    def get_feature_flags(self):
        if self._get_feature_flags_func:
            return self._get_feature_flags_func(deepcopy(self._feature_flags))

        return self._feature_flags

    def is_feature_enabled(self, feature):
        """Utility function for checking whether a feature is turned on"""
        return self.get_feature_flags().get(feature)