/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.logging.log4j.core.appender.mom.kafka;

import java.nio.charset.StandardCharsets;
import java.util.Objects;
import java.util.Properties;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;

import org.apache.kafka.clients.producer.Producer;
import org.apache.kafka.clients.producer.ProducerRecord;
import org.apache.kafka.clients.producer.RecordMetadata;
import org.apache.logging.log4j.core.LoggerContext;
import org.apache.logging.log4j.core.appender.AbstractManager;
import org.apache.logging.log4j.core.appender.ManagerFactory;
import org.apache.logging.log4j.core.config.Property;
import org.apache.logging.log4j.core.util.Log4jThread;

public class KafkaManager extends AbstractManager {

        public static final String DEFAULT_TIMEOUT_MILLIS = "30000";

        /**
         * package-private access for testing.
         */
        static KafkaProducerFactory producerFactory = new DefaultKafkaProducerFactory();

        private final Properties config = new Properties();
        private Producer<byte[], byte[]> producer;
        private final int timeoutMillis;

        private final String topic;
        private final String key;
        private final boolean syncSend;
        private static final KafkaManagerFactory factory = new KafkaManagerFactory();

        /*
         * The Constructor should have been declared private as all Managers are create
         * by the internal factory;
         */
        public KafkaManager(final LoggerContext loggerContext, final String name, final String topic,
                        final boolean syncSend, final Property[] properties, final String key) {
                super(loggerContext, name);
                this.topic = Objects.requireNonNull(topic, "topic");
                this.syncSend = syncSend;

                config.setProperty("key.serializer", "org.apache.kafka.common.serialization.ByteArraySerializer");
                config.setProperty("value.serializer", "org.apache.kafka.common.serialization.ByteArraySerializer");
                config.setProperty("batch.size", "0");

                for (final Property property : properties) {
                        config.setProperty(property.getName(), property.getValue());
                }

                this.key = key;

                this.timeoutMillis = Integer.parseInt(config.getProperty("timeout.ms", DEFAULT_TIMEOUT_MILLIS));
        }

        @Override
        public boolean releaseSub(final long timeout, final TimeUnit timeUnit) {
                if (timeout > 0) {
                        closeProducer(timeout, timeUnit);
                } else {
                        closeProducer(timeoutMillis, TimeUnit.MILLISECONDS);
                }
                return true;
        }

        private void closeProducer(final long timeout, final TimeUnit timeUnit) {
                if (producer != null) {
                        // This thread is a workaround for this Kafka issue:
                        // https://issues.apache.org/jira/browse/KAFKA-1660
                        final Thread closeThread = new Log4jThread(() -> {
                if (producer != null) {
                        producer.close();
                }
            }, "KafkaManager-CloseThread");
                        closeThread.setDaemon(true); // avoid blocking JVM shutdown
                        closeThread.start();
                        try {
                                closeThread.join(timeUnit.toMillis(timeout));
                        } catch (final InterruptedException ignore) {
                                Thread.currentThread().interrupt();
                                // ignore
                        }
                }
        }

        public void send(final byte[] msg) throws ExecutionException, InterruptedException, TimeoutException {
                if (producer != null) {
                        byte[] newKey = null;

                        if (key != null && key.contains("${")) {
                                newKey = getLoggerContext().getConfiguration().getStrSubstitutor().replace(key)
                                                .getBytes(StandardCharsets.UTF_8);
                        } else if (key != null) {
                                newKey = key.getBytes(StandardCharsets.UTF_8);
                        }

                        final ProducerRecord<byte[], byte[]> newRecord = new ProducerRecord<>(topic, newKey, msg);
                        if (syncSend) {
                                final Future<RecordMetadata> response = producer.send(newRecord);
                                response.get(timeoutMillis, TimeUnit.MILLISECONDS);
                        } else {
                                producer.send(newRecord, (metadata, e) -> {
                        if (e != null) {
                                LOGGER.error("Unable to write to Kafka in appender [" + getName() + "]", e);
                        }
                });
                        }
                }
        }

        public void startup() {
                if (producer == null) {
                        producer = producerFactory.newKafkaProducer(config);
                }
        }

        public String getTopic() {
                return topic;
        }

        public static KafkaManager getManager(final LoggerContext loggerContext, final String name, final String topic,
                        final boolean syncSend, final Property[] properties, final String key) {
                StringBuilder sb = new StringBuilder(name);
                for (Property prop : properties) {
                        sb.append(" ").append(prop.getName()).append("=").append(prop.getValue());
                }
                return getManager(sb.toString(), factory, new FactoryData(loggerContext, topic, syncSend, properties, key));
        }

        private static class FactoryData {
                private final LoggerContext loggerContext;
                private final String topic;
                private final boolean syncSend;
                private final Property[] properties;
                private final String key;

                public FactoryData(final LoggerContext loggerContext, final String topic, final boolean syncSend,
                                final Property[] properties, final String key) {
                        this.loggerContext = loggerContext;
                        this.topic = topic;
                        this.syncSend = syncSend;
                        this.properties = properties;
                        this.key = key;
                }

        }

        private static class KafkaManagerFactory implements ManagerFactory<KafkaManager, FactoryData> {
                @Override
                public KafkaManager createManager(String name, FactoryData data) {
                        return new KafkaManager(data.loggerContext, name, data.topic, data.syncSend, data.properties, data.key);
                }
        }

}