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/*
 * 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.ApiMaturityLevel;
import org.apache.hudi.PublicAPIClass;
import org.apache.hudi.PublicAPIMethod;
import org.apache.hudi.common.config.TypedProperties;
import org.apache.hudi.common.table.checkpoint.Checkpoint;
import org.apache.hudi.common.table.checkpoint.CheckpointUtils;
import org.apache.hudi.common.table.checkpoint.StreamerCheckpointV1;
import org.apache.hudi.common.table.checkpoint.StreamerCheckpointV2;
import org.apache.hudi.common.util.ConfigUtils;
import org.apache.hudi.common.util.Option;
import org.apache.hudi.utilities.callback.SourceCommitCallback;
import org.apache.hudi.utilities.schema.SchemaProvider;
import org.apache.hudi.utilities.streamer.DefaultStreamContext;
import org.apache.hudi.utilities.streamer.SourceProfileSupplier;
import org.apache.hudi.utilities.streamer.StreamContext;

import org.apache.spark.api.java.JavaSparkContext;
import org.apache.spark.sql.SparkSession;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.Serializable;

import static org.apache.hudi.config.HoodieWriteConfig.WRITE_TABLE_VERSION;

/**
 * Represents a source from which we can tail data. Assumes a constructor that takes properties.
 */
@PublicAPIClass(maturity = ApiMaturityLevel.STABLE)
public abstract class Source implements SourceCommitCallback, Serializable {
  private static final Logger LOG = LoggerFactory.getLogger(Source.class);

  public enum SourceType {
    JSON, AVRO, ROW, PROTO
  }

  protected transient TypedProperties props;
  protected transient JavaSparkContext sparkContext;
  protected transient SparkSession sparkSession;
  protected transient Option sourceProfileSupplier;
  protected int writeTableVersion;
  private transient SchemaProvider overriddenSchemaProvider;

  private final SourceType sourceType;

  protected Source(TypedProperties props, JavaSparkContext sparkContext, SparkSession sparkSession,
      SchemaProvider schemaProvider) {
    this(props, sparkContext, sparkSession, schemaProvider, SourceType.AVRO);
  }

  protected Source(TypedProperties props, JavaSparkContext sparkContext, SparkSession sparkSession,
      SchemaProvider schemaProvider, SourceType sourceType) {
    this(props, sparkContext, sparkSession, sourceType, new DefaultStreamContext(schemaProvider, Option.empty()));
  }

  protected Source(TypedProperties props, JavaSparkContext sparkContext, SparkSession sparkSession, SourceType sourceType, StreamContext streamContext) {
    this.props = props;
    this.sparkContext = sparkContext;
    this.sparkSession = sparkSession;
    this.overriddenSchemaProvider = streamContext.getSchemaProvider();
    this.sourceType = sourceType;
    this.sourceProfileSupplier = streamContext.getSourceProfileSupplier();
    this.writeTableVersion = ConfigUtils.getIntWithAltKeys(props, WRITE_TABLE_VERSION);
  }

  @Deprecated
  @PublicAPIMethod(maturity = ApiMaturityLevel.STABLE)
  protected abstract InputBatch fetchNewData(Option lastCkptStr, long sourceLimit);

  @PublicAPIMethod(maturity = ApiMaturityLevel.EVOLVING)
  protected InputBatch readFromCheckpoint(Option lastCheckpoint, long sourceLimit) {
    LOG.warn("In Hudi 1.0+, the checkpoint based on Hudi timeline is changed. "
        + "If your Source implementation relies on request time as the checkpoint, "
        + "you may consider migrating to completion time-based checkpoint by overriding "
        + "Source#translateCheckpoint and Source#fetchNewDataFromCheckpoint");
    return fetchNewData(
        lastCheckpoint.isPresent()
            ? Option.of(lastCheckpoint.get().getCheckpointKey()) : Option.empty(),
        sourceLimit);
  }

  @PublicAPIMethod(maturity = ApiMaturityLevel.EVOLVING)
  protected Option translateCheckpoint(Option lastCheckpoint) {
    if (lastCheckpoint.isEmpty()) {
      return Option.empty();
    }
    if (CheckpointUtils.targetCheckpointV2(writeTableVersion)) {
      // V2 -> V2
      if (lastCheckpoint.get() instanceof StreamerCheckpointV2) {
        return lastCheckpoint;
      }
      // V1 -> V2
      if (lastCheckpoint.get() instanceof StreamerCheckpointV1) {
        StreamerCheckpointV2 newCheckpoint = new StreamerCheckpointV2(lastCheckpoint.get());
        newCheckpoint.addV1Props();
        return Option.of(newCheckpoint);
      }
    } else {
      // V2 -> V1
      if (lastCheckpoint.get() instanceof StreamerCheckpointV2) {
        return Option.of(new StreamerCheckpointV1(lastCheckpoint.get()));
      }
      // V1 -> V1
      if (lastCheckpoint.get() instanceof StreamerCheckpointV1) {
        return lastCheckpoint;
      }
    }
    throw new UnsupportedOperationException("Unsupported checkpoint type: " + lastCheckpoint.get());
  }

  /**
   * Main API called by Hoodie Streamer to fetch records.
   *
   * @param lastCheckpoint Last Checkpoint
   * @param sourceLimit Source Limit
   * @return
   */
  public final InputBatch fetchNext(Option lastCheckpoint, long sourceLimit) {
    InputBatch batch = readFromCheckpoint(translateCheckpoint(lastCheckpoint), sourceLimit);
    // If overriddenSchemaProvider is passed in CLI, use it
    return overriddenSchemaProvider == null ? batch
        : new InputBatch<>(batch.getBatch(), batch.getCheckpointForNextBatch(), overriddenSchemaProvider);
  }

  public SourceType getSourceType() {
    return sourceType;
  }

  public SparkSession getSparkSession() {
    return sparkSession;
  }
}