/*
 * 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.hudi.utilities.sources;

import org.apache.hudi.common.config.TypedProperties;
import org.apache.hudi.common.util.Option;
import org.apache.hudi.utilities.deltastreamer.HoodieDeltaStreamerMetrics;
import org.apache.hudi.utilities.schema.SchemaProvider;
import org.apache.hudi.utilities.sources.helpers.KafkaOffsetGen;
import org.apache.hudi.utilities.sources.helpers.KafkaOffsetGen.CheckpointUtils;

import org.apache.kafka.common.serialization.StringDeserializer;
import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;
import org.apache.spark.api.java.JavaRDD;
import org.apache.spark.api.java.JavaSparkContext;
import org.apache.spark.sql.SparkSession;
import org.apache.spark.streaming.kafka010.KafkaUtils;
import org.apache.spark.streaming.kafka010.LocationStrategies;
import org.apache.spark.streaming.kafka010.OffsetRange;

/**
 * Read json kafka data.
 */
public class JsonKafkaSource extends JsonSource {

  private static final Logger LOG = LogManager.getLogger(JsonKafkaSource.class);

  private final KafkaOffsetGen offsetGen;

  private final HoodieDeltaStreamerMetrics metrics;

  public JsonKafkaSource(TypedProperties properties, JavaSparkContext sparkContext, SparkSession sparkSession,
                         SchemaProvider schemaProvider, HoodieDeltaStreamerMetrics metrics) {
    super(properties, sparkContext, sparkSession, schemaProvider);
    this.metrics = metrics;
    properties.put("key.deserializer", StringDeserializer.class);
    properties.put("value.deserializer", StringDeserializer.class);
    offsetGen = new KafkaOffsetGen(properties);
  }

  @Override
  protected InputBatch<JavaRDD<String>> fetchNewData(Option<String> lastCheckpointStr, long sourceLimit) {
    OffsetRange[] offsetRanges = offsetGen.getNextOffsetRanges(lastCheckpointStr, sourceLimit, metrics);
    long totalNewMsgs = CheckpointUtils.totalNewMessages(offsetRanges);
    LOG.info("About to read " + totalNewMsgs + " from Kafka for topic :" + offsetGen.getTopicName());
    if (totalNewMsgs <= 0) {
      return new InputBatch<>(Option.empty(), CheckpointUtils.offsetsToStr(offsetRanges));
    }
    JavaRDD<String> newDataRDD = toRDD(offsetRanges);
    return new InputBatch<>(Option.of(newDataRDD), CheckpointUtils.offsetsToStr(offsetRanges));
  }

  private JavaRDD<String> toRDD(OffsetRange[] offsetRanges) {
    return KafkaUtils.createRDD(sparkContext, offsetGen.getKafkaParams(), offsetRanges,
            LocationStrategies.PreferConsistent()).filter(x -> {
              String msgValue = (String) x.value();
              //Filter null messages from Kafka to prevent Exceptions
              return msgValue != null;
            }).map(x -> (String) x.value());
  }

  @Override
  public void onCommit(String lastCkptStr) {
    if (this.props.getBoolean(KafkaOffsetGen.Config.ENABLE_KAFKA_COMMIT_OFFSET.key(), KafkaOffsetGen.Config.ENABLE_KAFKA_COMMIT_OFFSET.defaultValue())) {
      offsetGen.commitOffsetToKafka(lastCkptStr);
    }
  }
}
