/**
 * ============LICENSE_START=======================================================
 * org.onap.aai
 * ================================================================================
 * Copyright © 2017-2018 AT&T Intellectual Property. All rights reserved.
 * Copyright © 2017-2018 Amdocs
 * ================================================================================
 * 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.aai.event;

import org.onap.aai.event.api.EventConsumer;

import org.apache.camel.Exchange;
import org.apache.camel.Message;
import org.apache.camel.Processor;
import org.apache.camel.impl.ScheduledPollConsumer;
import org.onap.aai.logging.RouterCoreMsgs;
import org.onap.aai.cl.api.Logger;
import org.onap.aai.cl.eelf.LoggerFactory;
import org.onap.aai.cl.mdc.MdcContext;

import java.util.Collections;
import java.util.UUID;
import java.util.concurrent.ScheduledThreadPoolExecutor;

/**
 * The consumer component which is used to pull messages off of the event bus and send them to the
 * next processor in the route chain. This type of consumer is based off of a scheduled poller so
 * that events are pulled on a regular basis.
 */
public class EventBusConsumer extends ScheduledPollConsumer {

  private Logger logger = LoggerFactory.getInstance().getLogger(EventBusConsumer.class);
  private Logger auditLogger = LoggerFactory.getInstance().getAuditLogger(EventBusConsumer.class);
  private final AbstractEventBusEndpoint endpoint;

  private EventConsumer consumer;

  /**
   * EventBusConsumer Constructor.
   */
  public EventBusConsumer(AbstractEventBusEndpoint endpoint, Processor processor, EventConsumer consumer) {
    super(endpoint, processor);
    super.setDelay(endpoint.getPollingDelay());
    this.endpoint = endpoint;

    setScheduledExecutorService(new ScheduledThreadPoolExecutor(endpoint.getPoolSize()));

    this.consumer = consumer;
  }

  /**
   * Method which is called by the Camel process on a scheduled basis. This specific implementation
   * reads messages off of the configured topic and schedules tasks to process them .
   * 
   * @return the number of messages that were processed off the event queue
   */
  @Override
  protected int poll() throws Exception {

    String topic = endpoint.getEventTopic();

    logger.debug("Checking for event on topic: " + topic);

    int processCount = 0;

    try {
      Iterable<String> messages = consumer.consumeAndCommit();

      for (String message : messages) {
        Exchange exchange = endpoint.createExchange();
        exchange.getIn().setBody(message);
        getScheduledExecutorService().submit(new EventProcessor(exchange, topic));
        ++processCount;
      }
    } catch (Exception e) {
      logger.error(RouterCoreMsgs.EVENT_PROCESSING_EXCEPTION, e, e.getLocalizedMessage());
    }

    logger.debug(RouterCoreMsgs.PROCESS_EVENT, topic, Integer.toString(processCount));

    return processCount;
  }
  @Override
  protected void doStop() throws Exception {
    super.doStop();
    if (endpoint != null) {
      endpoint.close();
    }
  }
  @Override
  protected void doShutdown() throws Exception {
    super.doShutdown();
    if (endpoint != null) {
      endpoint.close();
    }
  }

  /**
   * Class responsible for processing messages pulled off of the event bus.
   */
  private class EventProcessor implements Runnable {

    private Exchange message;

    private String topic;

    EventProcessor(Exchange message, String topic) {
      this.message = message;
      this.topic = topic;
    }
	@Override
    public void run() {
      try {

        MdcContext.initialize(UUID.randomUUID().toString(), "DataRouter", "", "Event-Bus", "");

        // Sends the message to the next processor in the defined Camel route
        getProcessor().process(message);

        Message response = message.getOut();
        if (response != null) {
          logger.debug("Routing response: " + response.getBody());
        }

      } catch (Exception e) {
        logger.error(RouterCoreMsgs.EVENT_PROCESSING_EXCEPTION,e,e.getLocalizedMessage());
      } finally {
        // log exception if an exception occurred and was not handled
        if (message.getException() != null) {
          logger.info(RouterCoreMsgs.PROCESS_EVENT, topic, "FAILURE");
          auditLogger.info(RouterCoreMsgs.PROCESS_EVENT, topic, "FAILURE");
        } else {
          logger.info(RouterCoreMsgs.PROCESS_EVENT, topic, "SUCCESS");
          auditLogger.info(RouterCoreMsgs.PROCESS_EVENT, topic, "SUCCESS");
        }
      }
    }
  }
}