/*
 * ============LICENSE_START=======================================================
 * PNF-REGISTRATION-HANDLER
 * ================================================================================
 * Copyright (C) 2018 NOKIA Intellectual Property. 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.
 * ============LICENSE_END=========================================================
 */

package org.onap.dcaegen2.services.prh.tasks;

import static org.onap.dcaegen2.services.prh.model.logging.MdcVariables.INSTANCE_UUID;
import static org.onap.dcaegen2.services.prh.model.logging.MdcVariables.RESPONSE_CODE;

import java.util.Map;
import java.util.UUID;
import java.util.concurrent.CountDownLatch;
import javax.net.ssl.SSLException;
import org.onap.dcaegen2.services.prh.exceptions.DmaapEmptyResponseException;
import org.onap.dcaegen2.services.prh.exceptions.PrhTaskException;
import org.onap.dcaegen2.services.prh.model.ConsumerDmaapModel;
import org.onap.dcaegen2.services.prh.model.logging.MdcVariables;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.slf4j.MDC;
import org.slf4j.Marker;
import org.slf4j.MarkerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Component;
import reactor.core.publisher.Mono;

/**
 * @author <a href="mailto:przemyslaw.wasala@nokia.com">Przemysław Wąsala</a> on 3/23/18
 */
@Component
public class ScheduledTasks {

    private static final Logger logger = LoggerFactory.getLogger(ScheduledTasks.class);
    private static final Marker INVOKE = MarkerFactory.getMarker("INVOKE");
    private final DmaapConsumerTask dmaapConsumerTask;
    private final DmaapPublisherTask dmaapProducerTask;
    private final AaiProducerTask aaiProducerTask;
    private Map<String, String> mdcContextMap;

    /**
     * Constructor for tasks registration in PRHWorkflow.
     *
     * @param dmaapConsumerTask - fist task
     * @param dmaapPublisherTask - third task
     * @param aaiPublisherTask - second task
     */
    @Autowired
    public ScheduledTasks(DmaapConsumerTask dmaapConsumerTask, DmaapPublisherTask dmaapPublisherTask,
        AaiProducerTask aaiPublisherTask, Map<String, String> mdcContextMap) {
        this.dmaapConsumerTask = dmaapConsumerTask;
        this.dmaapProducerTask = dmaapPublisherTask;
        this.aaiProducerTask = aaiPublisherTask;
        this.mdcContextMap = mdcContextMap;
    }

    /**
     * Main function for scheduling prhWorkflow.
     */
    public void scheduleMainPrhEventTask() {
        MdcVariables.setMdcContextMap(mdcContextMap);
        try {
            logger.trace("Execution of tasks was registered");
            CountDownLatch mainCountDownLatch = new CountDownLatch(1);
            consumeFromDMaaPMessage()
                .doOnError(DmaapEmptyResponseException.class, error ->
                    logger.warn("Nothing to consume from DMaaP")
                )
                .flatMap(this::publishToAaiConfiguration)
                .flatMap(this::publishToDmaapConfiguration)
                .doOnTerminate(mainCountDownLatch::countDown)
                .subscribe(this::onSuccess, this::onError, this::onComplete);

            mainCountDownLatch.await();
        } catch (InterruptedException e) {
            logger.warn("Interruption problem on countDownLatch ", e);
            Thread.currentThread().interrupt();
        }
    }


    private void onComplete() {
        logger.info("PRH tasks have been completed");
    }

    private void onSuccess(ResponseEntity<String> responseCode) {
        MDC.put(RESPONSE_CODE, responseCode.getStatusCode().toString());
        logger.info("Prh consumed tasks successfully. HTTP Response code from DMaaPProducer {}",
            responseCode.getStatusCode().value());
        MDC.remove(RESPONSE_CODE);
    }

    private void onError(Throwable throwable) {
        if (!(throwable instanceof DmaapEmptyResponseException)) {
            logger.warn("Chain of tasks have been aborted due to errors in PRH workflow", throwable);
        }
    }


    private Mono<ConsumerDmaapModel> consumeFromDMaaPMessage() {
        return Mono.defer(() -> {
            MdcVariables.setMdcContextMap(mdcContextMap);
            MDC.put(INSTANCE_UUID, UUID.randomUUID().toString());
            logger.info(INVOKE, "Init configs");
            dmaapConsumerTask.initConfigs();
            return dmaapConsumerTask.execute("");
        });
    }

    private Mono<ConsumerDmaapModel> publishToAaiConfiguration(ConsumerDmaapModel monoDMaaPModel) {
        try {
            return aaiProducerTask.execute(monoDMaaPModel);
        } catch (PrhTaskException | SSLException e) {
            return Mono.error(e);
        }
    }

    private Mono<ResponseEntity<String>> publishToDmaapConfiguration(ConsumerDmaapModel monoAaiModel) {
        try {
            return dmaapProducerTask.execute(monoAaiModel);
        } catch (PrhTaskException e) {
            return Mono.error(e);
        }
    }
}