/*
 * Copyright (c) 2015, WSO2 Inc. (http://www.wso2.org) 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.
 */
package org.wso2.carbon.event.input.adapter.kafka;

import com.google.common.util.concurrent.ThreadFactoryBuilder;
import kafka.consumer.ConsumerConfig;
import kafka.consumer.KafkaStream;
import kafka.javaapi.consumer.ConsumerConnector;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.wso2.carbon.event.input.adapter.core.InputEventAdapterListener;

import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class ConsumerKafkaAdaptor {
    private final ConsumerConnector consumer;
    private final String topic;
    private ExecutorService executor;
    private Log log = LogFactory.getLog(ConsumerKafkaAdaptor.class);
    private int tenantId;

    public ConsumerKafkaAdaptor(String inTopic, int tenantId,
                                ConsumerConfig conf) {
        consumer = kafka.consumer.Consumer.createJavaConsumerConnector(conf);
        this.topic = inTopic;
        this.tenantId = tenantId;
    }

    public void shutdown() {
        if (consumer != null) {
            consumer.shutdown();
        }
        if (executor != null) {
            executor.shutdown();
        }
    }

    public void run(int numThreads, InputEventAdapterListener brokerListener) {
        try {
            Map<String, Integer> topicCountMap = new HashMap<String, Integer>();
            topicCountMap.put(topic, numThreads);
            Map<String, List<KafkaStream<byte[], byte[]>>> consumerMap = consumer.createMessageStreams(topicCountMap);
            List<KafkaStream<byte[], byte[]>> streams = consumerMap.get(topic);

            // now launch all the threads
            //
            executor = Executors.newFixedThreadPool(numThreads,new ThreadFactoryBuilder().
                    setNameFormat("Thread pool- component - ConsumerKafkaAdaptor.executor").build());

            // now create an object to consume the messages
            //
            for (final KafkaStream stream : streams) {

                executor.submit(new KafkaConsumer(stream, brokerListener, tenantId));
            }
        } catch (Throwable t) {
            log.error("Error while creating KafkaConsumer ", t);
        }
    }
}