/*
 * 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.iotdb.rpc;

import org.apache.thrift.transport.TTransport;
import org.apache.thrift.transport.TTransportException;
import org.apache.thrift.transport.layered.TFramedTransport;

import java.io.IOException;

public abstract class TCompressedElasticFramedTransport extends TElasticFramedTransport {

  private AutoScalingBufferWriteTransport writeCompressBuffer;
  private AutoScalingBufferReadTransport readCompressBuffer;

  protected TCompressedElasticFramedTransport(
      TTransport underlying, int thriftDefaultBufferSize, int thriftMaxFrameSize) {
    super(underlying, thriftDefaultBufferSize, thriftMaxFrameSize);
    writeCompressBuffer = new AutoScalingBufferWriteTransport(thriftDefaultBufferSize);
    readCompressBuffer = new AutoScalingBufferReadTransport(thriftDefaultBufferSize);
  }

  @Override
  protected void readFrame() throws TTransportException {
    underlying.readAll(i32buf, 0, 4);
    int size = TFramedTransport.decodeFrameSize(i32buf);

    if (size < 0) {
      close();
      throw new TTransportException(
          TTransportException.CORRUPTED_DATA, "Read a negative frame size (" + size + ")!");
    }

    readBuffer.fill(underlying, size);
    RpcStat.readCompressedBytes.addAndGet(size);
    try {
      int uncompressedLength = uncompressedLength(readBuffer.getBuffer(), 0, size);
      RpcStat.readBytes.addAndGet(uncompressedLength);
      readCompressBuffer.resizeIfNecessary(uncompressedLength);
      uncompress(readBuffer.getBuffer(), 0, size, readCompressBuffer.getBuffer(), 0);
      readCompressBuffer.limit(uncompressedLength);
      readCompressBuffer.position(0);
      readBuffer.fill(readCompressBuffer, uncompressedLength);
    } catch (IOException e) {
      throw new TTransportException(e);
    }
  }

  @Override
  public void flush() throws TTransportException {
    int length = writeBuffer.getPos();
    RpcStat.writeBytes.addAndGet(length);
    try {
      int maxCompressedLength = maxCompressedLength(length);
      writeCompressBuffer.resizeIfNecessary(maxCompressedLength);
      int compressedLength =
          compress(writeBuffer.getBuffer(), 0, length, writeCompressBuffer.getBuffer(), 0);
      RpcStat.writeCompressedBytes.addAndGet(compressedLength);
      TFramedTransport.encodeFrameSize(compressedLength, i32buf);
      underlying.write(i32buf, 0, 4);
      underlying.write(writeCompressBuffer.getBuffer(), 0, compressedLength);
    } catch (IOException e) {
      throw new TTransportException(e);
    }

    writeBuffer.reset();
    if (thriftDefaultBufferSize < length) {
      writeBuffer.resizeIfNecessary(thriftDefaultBufferSize);
    }
    underlying.flush();
  }

  protected abstract int uncompressedLength(byte[] but, int off, int len) throws IOException;

  protected abstract int maxCompressedLength(int len);

  protected abstract int compress(byte[] input, int inOff, int len, byte[] output, int outOff)
      throws IOException;

  protected abstract void uncompress(byte[] input, int inOff, int size, byte[] output, int outOff)
      throws IOException;
}