/**
 * Copyright (C) 2014-2016 LinkedIn Corp. (pinot-core@linkedin.com)
 *
 * 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.
 */
package com.linkedin.pinot.core.realtime.impl.kafka;

import java.lang.reflect.Method;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;


/**
 * This is a work around for kafka 8 and 9.
 *
 * In order to consume data from kafka using simple consumer, we need to know the leader kafka
 * broker for each kafka partition from {@link kafka.javaapi.PartitionMetadata}. But
 * {@link kafka.javaapi.PartitionMetadata} will give two different type of objects in kafka8 and kafka9.
 *
 * In kafka8, it will give {@link kafka.cluster.Broker}.
 * In kafka9, it will give {@link kafka.cluster.BrokerEndPoint}.
 *
 * In Pinot, we need to get host and port from this leader broker object, so this wrapper is made
 * to treat {@link kafka.cluster.Broker} and {@link kafka.cluster.BrokerEndPoint} as object, and
 * underlying use java reflection to provide the method access to host() method for
 * {@link kafka.cluster.Broker#host()} and {@link kafka.cluster.BrokerEndPoint#host()},
 * as long as port method: {@link kafka.cluster.Broker#port()} and {@link kafka.cluster.BrokerEndPoint#port()}.
 *
 */
public class KafkaBrokerWrapper {

  private static final Logger LOGGER = LoggerFactory.getLogger(KafkaBrokerWrapper.class);

  private final Object _kafkaBroker;

  public KafkaBrokerWrapper(Object kafkaBroker) {
    this._kafkaBroker = kafkaBroker;
  }

  public String host() {
    if (_kafkaBroker != null) {
      try {
        Method method = _kafkaBroker.getClass().getMethod("host", new Class<?>[0]);
        return (String) method.invoke(_kafkaBroker);
      } catch (Exception e) {
        LOGGER.error("Failed to get host() method from KafkaBroker Object: {}", _kafkaBroker, e);
      }
    }
    return "";
  }

  public int port() {
    if (_kafkaBroker != null) {
      try {
        Method method = _kafkaBroker.getClass().getMethod("port", new Class<?>[0]);
        return (int) method.invoke(_kafkaBroker);
      } catch (Exception e) {
        LOGGER.error("Failed to get port() method from KafkaBroker Object: {}", _kafkaBroker, e);
      }
    }
    return 0;
  }
}