/*
 *  ============LICENSE_START=======================================================
 *  Copyright (C) 2022 Nordix 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.
 *
 *  SPDX-License-Identifier: Apache-2.0
 *  ============LICENSE_END=========================================================
 */

package org.onap.cps.ncmp.rest.controller.handlers;

import java.util.Map;
import java.util.UUID;
import java.util.function.Supplier;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.onap.cps.ncmp.api.NetworkCmProxyDataService;
import org.onap.cps.ncmp.rest.executor.CpsNcmpTaskExecutor;
import org.onap.cps.ncmp.rest.util.TopicValidator;
import org.onap.cps.spi.FetchDescendantsOption;
import org.springframework.http.ResponseEntity;

@RequiredArgsConstructor
@Slf4j
public abstract class NcmpDatastoreRequestHandler {

    private static final String NO_REQUEST_ID = null;
    private static final String NO_TOPIC = null;

    protected final NetworkCmProxyDataService networkCmProxyDataService;
    protected final CpsNcmpTaskExecutor cpsNcmpTaskExecutor;
    protected final int timeOutInMilliSeconds;
    protected final boolean notificationFeatureEnabled;

    protected abstract Supplier<Object> getTaskSupplier(final String cmHandle,
                                                        final String resourceIdentifier,
                                                        final String optionsParamInQuery,
                                                        final String topicParamInQuery,
                                                        final String requestId,
                                                        final Boolean includeDescendant);

    /**
     * Execute a request on a datastore.
     *
     * @param cmHandleId          the cm handle
     * @param resourceIdentifier  the resource identifier
     * @param optionsParamInQuery the options param in query
     * @param topicParamInQuery   the topic param in query
     * @param includeDescendants  whether include descendants
     * @return the response entity
     */
    public ResponseEntity<Object> executeRequest(final String cmHandleId,
                                                 final String resourceIdentifier,
                                                 final String optionsParamInQuery,
                                                 final String topicParamInQuery,
                                                 final Boolean includeDescendants) {

        final boolean asyncResponseRequested = topicParamInQuery != null;
        if (asyncResponseRequested && notificationFeatureEnabled) {
            final String requestId = UUID.randomUUID().toString();
            final Supplier<Object> taskSupplier = getTaskSupplier(cmHandleId, resourceIdentifier, optionsParamInQuery,
                topicParamInQuery, requestId, includeDescendants);
            return executeTaskAsync(topicParamInQuery, requestId, taskSupplier);
        }

        if (asyncResponseRequested) {
            log.warn("Asynchronous request is unavailable as notification feature is currently disabled, "
                + "will use synchronous operation.");
        }
        final Supplier<Object> taskSupplier = getTaskSupplier(cmHandleId, resourceIdentifier, optionsParamInQuery,
            NO_TOPIC, NO_REQUEST_ID, includeDescendants);
        return executeTaskSync(taskSupplier);
    }

    protected ResponseEntity<Object> executeTaskAsync(final String topicParamInQuery,
                                                      final String requestId,
                                                      final Supplier<Object> taskSupplier) {

        TopicValidator.validateTopicName(topicParamInQuery);
        log.debug("Received Async request with id {}", requestId);
        cpsNcmpTaskExecutor.executeTask(taskSupplier, timeOutInMilliSeconds);

        return ResponseEntity.ok(Map.of("requestId", requestId));
    }

    protected ResponseEntity<Object> executeTaskSync(final Supplier<Object> taskSupplier) {
        return ResponseEntity.ok(taskSupplier.get());
    }

    protected static FetchDescendantsOption getFetchDescendantsOption(final Boolean includeDescendant) {
        return Boolean.TRUE.equals(includeDescendant) ? FetchDescendantsOption.INCLUDE_ALL_DESCENDANTS
            : FetchDescendantsOption.OMIT_DESCENDANTS;
    }

}