/*
 * Copyright 2018-present Open Networking Foundation
 *
 * 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.onosproject.openstacktelemetry.impl;

import org.apache.felix.scr.annotations.Activate;
import org.apache.felix.scr.annotations.Component;
import org.apache.felix.scr.annotations.Deactivate;
import org.apache.felix.scr.annotations.Reference;
import org.apache.felix.scr.annotations.ReferenceCardinality;
import org.apache.felix.scr.annotations.Service;
import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.Producer;
import org.apache.kafka.clients.producer.ProducerRecord;
import org.apache.kafka.clients.producer.RecordMetadata;
import org.onosproject.openstacktelemetry.api.KafkaTelemetryAdminService;
import org.onosproject.openstacktelemetry.api.OpenstackTelemetryService;
import org.onosproject.openstacktelemetry.api.config.KafkaTelemetryConfig;
import org.onosproject.openstacktelemetry.api.config.TelemetryConfig;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Properties;
import java.util.concurrent.Future;

/**
 * Kafka telemetry manager.
 */
@Component(immediate = true)
@Service
public class KafkaTelemetryManager implements KafkaTelemetryAdminService {

    private final Logger log = LoggerFactory.getLogger(getClass());

    private static final String BOOTSTRAP_SERVERS = "bootstrap.servers";
    private static final String RETRIES = "retries";
    private static final String ACKS = "acks";
    private static final String BATCH_SIZE = "batch.size";
    private static final String LINGER_MS = "linger.ms";
    private static final String MEMORY_BUFFER = "buffer.memory";
    private static final String KEY_SERIALIZER = "key.serializer";
    private static final String VALUE_SERIALIZER = "value.serializer";

    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
    protected OpenstackTelemetryService openstackTelemetryService;

    private Producer<String, byte[]> producer = null;

    @Activate
    protected void activate() {

        openstackTelemetryService.addTelemetryService(this);

        log.info("Started");
    }

    @Deactivate
    protected void deactivate() {
        stop();

        openstackTelemetryService.removeTelemetryService(this);

        log.info("Stopped");
    }

    @Override
    public void start(TelemetryConfig config) {
        if (producer != null) {
            log.info("Kafka producer has already been started");
            return;
        }

        KafkaTelemetryConfig kafkaConfig = (KafkaTelemetryConfig) config;

        StringBuilder kafkaServerBuilder = new StringBuilder();
        kafkaServerBuilder.append(kafkaConfig.address());
        kafkaServerBuilder.append(":");
        kafkaServerBuilder.append(kafkaConfig.port());

        // Configure Kafka server properties
        Properties prop = new Properties();
        prop.put(BOOTSTRAP_SERVERS, kafkaServerBuilder.toString());
        prop.put(RETRIES, kafkaConfig.retries());
        prop.put(ACKS, kafkaConfig.requiredAcks());
        prop.put(BATCH_SIZE, kafkaConfig.batchSize());
        prop.put(LINGER_MS, kafkaConfig.lingerMs());
        prop.put(MEMORY_BUFFER, kafkaConfig.memoryBuffer());
        prop.put(KEY_SERIALIZER, kafkaConfig.keySerializer());
        prop.put(VALUE_SERIALIZER, kafkaConfig.valueSerializer());

        producer = new KafkaProducer<>(prop);
        log.info("Kafka producer has Started");
    }

    @Override
    public void stop() {
        if (producer != null) {
            producer.close();
            producer = null;
        }

        log.info("Kafka producer has Stopped");
    }

    @Override
    public void restart(TelemetryConfig config) {
        stop();
        start(config);
    }

    @Override
    public Future<RecordMetadata> publish(ProducerRecord<String, byte[]> record) {

        if (producer == null) {
            log.warn("Kafka telemetry service has not been enabled!");
            return null;
        }

        log.debug("Send telemetry record to kafka server...");
        return producer.send(record);
    }

    @Override
    public boolean isRunning() {
        return producer != null;
    }
}