content: /*
   * 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.kafka.connect.mirror;
  
  import org.apache.kafka.clients.consumer.ConsumerRecord;
  import org.apache.kafka.clients.consumer.OffsetAndMetadata;
  import org.apache.kafka.common.TopicPartition;
  import org.apache.kafka.common.protocol.types.Field;
  import org.apache.kafka.common.protocol.types.Schema;
  import org.apache.kafka.common.protocol.types.Struct;
  import org.apache.kafka.common.protocol.types.Type;
  
  import java.nio.ByteBuffer;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Objects;
  
  /**
   * Checkpoint records emitted by MirrorCheckpointConnector.
   */
  public class Checkpoint {
      public static final String TOPIC_KEY = "topic";
      public static final String PARTITION_KEY = "partition";
      public static final String CONSUMER_GROUP_ID_KEY = "group";
      public static final String UPSTREAM_OFFSET_KEY = "upstreamOffset";
      public static final String DOWNSTREAM_OFFSET_KEY = "offset";
      public static final String METADATA_KEY = "metadata";
      public static final String VERSION_KEY = "version";
      public static final short VERSION = 0;
  
      public static final Schema VALUE_SCHEMA_V0 = new Schema(
              new Field(UPSTREAM_OFFSET_KEY, Type.INT64),
              new Field(DOWNSTREAM_OFFSET_KEY, Type.INT64),
              new Field(METADATA_KEY, Type.STRING));
  
      public static final Schema KEY_SCHEMA = new Schema(
              new Field(CONSUMER_GROUP_ID_KEY, Type.STRING),
              new Field(TOPIC_KEY, Type.STRING),
              new Field(PARTITION_KEY, Type.INT32));
  
      public static final Schema HEADER_SCHEMA = new Schema(
              new Field(VERSION_KEY, Type.INT16));
  
      private final String consumerGroupId;
      private final TopicPartition topicPartition;
      private final long upstreamOffset;
      private final long downstreamOffset;
      private final String metadata;
  
      public Checkpoint(String consumerGroupId, TopicPartition topicPartition, long upstreamOffset,
              long downstreamOffset, String metadata) {
          this.consumerGroupId = consumerGroupId;
          this.topicPartition = topicPartition;
          this.upstreamOffset = upstreamOffset;
          this.downstreamOffset = downstreamOffset;
          this.metadata = metadata;
      }
  
      public String consumerGroupId() {
          return consumerGroupId;
      }
  
      public TopicPartition topicPartition() {
          return topicPartition;
      }
  
      public long upstreamOffset() {
          return upstreamOffset;
      }
  
      public long downstreamOffset() {
          return downstreamOffset;
      }
  
      public String metadata() {
          return metadata;
      }
  
      public OffsetAndMetadata offsetAndMetadata() {
          return new OffsetAndMetadata(downstreamOffset, metadata);
      }
  
      @Override
      public String toString() {
          return String.format("Checkpoint{consumerGroupId=%s, topicPartition=%s, "
              + "upstreamOffset=%d, downstreamOffset=%d, metadata=%s}",
              consumerGroupId, topicPartition, upstreamOffset, downstreamOffset, metadata);
      }
  
      ByteBuffer serializeValue(short version) {
          Struct header = headerStruct(version);
          Schema valueSchema = valueSchema(version);
          Struct valueStruct = valueStruct(valueSchema);
          ByteBuffer buffer = ByteBuffer.allocate(HEADER_SCHEMA.sizeOf(header) + valueSchema.sizeOf(valueStruct));
          HEADER_SCHEMA.write(buffer, header);
          valueSchema.write(buffer, valueStruct);
          buffer.flip();
          return buffer;
      }
  
      ByteBuffer serializeKey() {
          Struct struct = keyStruct();
          ByteBuffer buffer = ByteBuffer.allocate(KEY_SCHEMA.sizeOf(struct));
          KEY_SCHEMA.write(buffer, struct);
          buffer.flip();
          return buffer;
      }
  
      public static Checkpoint deserializeRecord(ConsumerRecord<byte[], byte[]> record) {
          ByteBuffer value = ByteBuffer.wrap(record.value());
          Struct header = HEADER_SCHEMA.read(value);
          short version = header.getShort(VERSION_KEY);
          Schema valueSchema = valueSchema(version);
          Struct valueStruct = valueSchema.read(value);
          long upstreamOffset = valueStruct.getLong(UPSTREAM_OFFSET_KEY);
          long downstreamOffset = valueStruct.getLong(DOWNSTREAM_OFFSET_KEY);
          String metadata = valueStruct.getString(METADATA_KEY);
          Struct keyStruct = KEY_SCHEMA.read(ByteBuffer.wrap(record.key()));
          String group = keyStruct.getString(CONSUMER_GROUP_ID_KEY);
          String topic = keyStruct.getString(TOPIC_KEY);
          int partition = keyStruct.getInt(PARTITION_KEY);
          return new Checkpoint(group, new TopicPartition(topic, partition), upstreamOffset,
              downstreamOffset, metadata);
      }
  
      private static Schema valueSchema(short version) {
          assert version == 0;
          return VALUE_SCHEMA_V0;
      }
  
      private Struct valueStruct(Schema schema) {
          Struct struct = new Struct(schema);
          struct.set(UPSTREAM_OFFSET_KEY, upstreamOffset);
          struct.set(DOWNSTREAM_OFFSET_KEY, downstreamOffset);
          struct.set(METADATA_KEY, metadata);
          return struct;
      }
  
      private Struct keyStruct() {
          Struct struct = new Struct(KEY_SCHEMA);
          struct.set(CONSUMER_GROUP_ID_KEY, consumerGroupId);
          struct.set(TOPIC_KEY, topicPartition.topic());
          struct.set(PARTITION_KEY, topicPartition.partition());
          return struct;
      }
  
      private Struct headerStruct(short version) {
          Struct struct = new Struct(HEADER_SCHEMA);
          struct.set(VERSION_KEY, version);
          return struct;
      }
  
      Map<String, ?> connectPartition() {
          Map<String, Object> partition = new HashMap<>();
          partition.put(CONSUMER_GROUP_ID_KEY, consumerGroupId);
          partition.put(TOPIC_KEY, topicPartition.topic());
          partition.put(PARTITION_KEY, topicPartition.partition());
          return partition;
      }
  
      static String unwrapGroup(Map<String, ?> connectPartition) {
          return connectPartition.get(CONSUMER_GROUP_ID_KEY).toString();
      }
  
      byte[] recordKey() {
          return serializeKey().array();
      }
  
      byte[] recordValue() {
          return serializeValue(VERSION).array();
      }
  
      @Override
      public boolean equals(Object o) {
          if (this == o) return true;
          if (o == null || getClass() != o.getClass()) return false;
          Checkpoint that = (Checkpoint) o;
          return upstreamOffset == that.upstreamOffset && downstreamOffset == that.downstreamOffset && Objects.equals(consumerGroupId, that.consumerGroupId) && Objects.equals(topicPartition, that.topicPartition) && Objects.equals(metadata, that.metadata);
      }
  
      @Override
      public int hashCode() {
          return Objects.hash(consumerGroupId, topicPartition, upstreamOffset, downstreamOffset, metadata);
      }
  }
  