/**
 * 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.hadoop.hdfs.protocol.datatransfer;


import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
import org.apache.hadoop.hdfs.protocol.HdfsProtoUtil;
import org.apache.hadoop.hdfs.protocol.proto.DataTransferProtos.BaseHeaderProto;
import org.apache.hadoop.hdfs.protocol.proto.DataTransferProtos.ChecksumProto;
import org.apache.hadoop.hdfs.protocol.proto.DataTransferProtos.ChecksumProto.ChecksumType;
import org.apache.hadoop.hdfs.protocol.proto.DataTransferProtos.ClientOperationHeaderProto;
import org.apache.hadoop.hdfs.protocol.proto.DataTransferProtos.OpWriteBlockProto;
import org.apache.hadoop.hdfs.security.token.block.BlockTokenIdentifier;
import org.apache.hadoop.security.token.Token;
import org.apache.hadoop.util.DataChecksum;

import com.google.common.collect.BiMap;
import com.google.common.collect.ImmutableBiMap;


/**
 * Static utilities for dealing with the protocol buffers used by the
 * Data Transfer Protocol.
 */
@InterfaceAudience.Private
@InterfaceStability.Evolving
public abstract class DataTransferProtoUtil {

  /**
   * Map between the internal DataChecksum identifiers and the protobuf-
   * generated identifiers on the wire.
   */
  static BiMap<Integer, ChecksumProto.ChecksumType> checksumTypeMap =
    ImmutableBiMap.<Integer, ChecksumProto.ChecksumType>builder()
      .put(DataChecksum.CHECKSUM_CRC32, ChecksumProto.ChecksumType.CRC32)
      .put(DataChecksum.CHECKSUM_CRC32C, ChecksumProto.ChecksumType.CRC32C)
      .put(DataChecksum.CHECKSUM_NULL, ChecksumProto.ChecksumType.NULL)
      .build();

  
  static BlockConstructionStage fromProto(
      OpWriteBlockProto.BlockConstructionStage stage) {
    return BlockConstructionStage.valueOf(BlockConstructionStage.class,
        stage.name());
  }

  static OpWriteBlockProto.BlockConstructionStage toProto(
      BlockConstructionStage stage) {
    return OpWriteBlockProto.BlockConstructionStage.valueOf(
        stage.name());
  }

  public static ChecksumProto toProto(DataChecksum checksum) {
    ChecksumType type = checksumTypeMap.get(checksum.getChecksumType());
    if (type == null) {
      throw new IllegalArgumentException(
          "Can't convert checksum to protobuf: " + checksum);
    }

    return ChecksumProto.newBuilder()
      .setBytesPerChecksum(checksum.getBytesPerChecksum())
      .setType(type)
      .build();
  }

  public static DataChecksum fromProto(ChecksumProto proto) {
    if (proto == null) return null;

    int bytesPerChecksum = proto.getBytesPerChecksum();
    int type = checksumTypeMap.inverse().get(proto.getType());
    
    return DataChecksum.newDataChecksum(type, bytesPerChecksum);
  }

  static ClientOperationHeaderProto buildClientHeader(ExtendedBlock blk,
      String client, Token<BlockTokenIdentifier> blockToken) {
    ClientOperationHeaderProto header =
      ClientOperationHeaderProto.newBuilder()
        .setBaseHeader(buildBaseHeader(blk, blockToken))
        .setClientName(client)
        .build();
    return header;
  }

  static BaseHeaderProto buildBaseHeader(ExtendedBlock blk,
      Token<BlockTokenIdentifier> blockToken) {
    return BaseHeaderProto.newBuilder()
      .setBlock(HdfsProtoUtil.toProto(blk))
      .setToken(HdfsProtoUtil.toProto(blockToken))
      .build();
  }
}
