/*
 * 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.db.pipe.connector.protocol.pipeconsensus.payload.builder;

import org.apache.iotdb.common.rpc.thrift.TConsensusGroupId;
import org.apache.iotdb.commons.consensus.index.ProgressIndex;
import org.apache.iotdb.commons.pipe.event.EnrichedEvent;
import org.apache.iotdb.consensus.pipe.thrift.TCommitId;
import org.apache.iotdb.consensus.pipe.thrift.TPipeConsensusTransferReq;
import org.apache.iotdb.db.pipe.connector.protocol.pipeconsensus.payload.request.PipeConsensusTabletBatchReq;
import org.apache.iotdb.db.pipe.connector.protocol.pipeconsensus.payload.request.PipeConsensusTabletBinaryReq;
import org.apache.iotdb.db.pipe.connector.protocol.pipeconsensus.payload.request.PipeConsensusTabletInsertNodeReq;
import org.apache.iotdb.db.pipe.event.common.tablet.PipeInsertNodeTabletInsertionEvent;
import org.apache.iotdb.db.pipe.resource.PipeDataNodeResourceManager;
import org.apache.iotdb.db.pipe.resource.memory.PipeMemoryBlock;
import org.apache.iotdb.db.queryengine.plan.planner.plan.node.write.InsertNode;
import org.apache.iotdb.db.storageengine.dataregion.wal.exception.WALPipeException;
import org.apache.iotdb.pipe.api.customizer.parameter.PipeParameters;
import org.apache.iotdb.pipe.api.event.Event;
import org.apache.iotdb.pipe.api.event.dml.insertion.TabletInsertionEvent;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Objects;

import static org.apache.iotdb.commons.pipe.config.constant.PipeConnectorConstant.CONNECTOR_IOTDB_BATCH_DELAY_KEY;
import static org.apache.iotdb.commons.pipe.config.constant.PipeConnectorConstant.CONNECTOR_IOTDB_BATCH_SIZE_KEY;
import static org.apache.iotdb.commons.pipe.config.constant.PipeConnectorConstant.CONNECTOR_IOTDB_PLAIN_BATCH_DELAY_DEFAULT_VALUE;
import static org.apache.iotdb.commons.pipe.config.constant.PipeConnectorConstant.CONNECTOR_IOTDB_PLAIN_BATCH_SIZE_DEFAULT_VALUE;
import static org.apache.iotdb.commons.pipe.config.constant.PipeConnectorConstant.SINK_IOTDB_BATCH_DELAY_KEY;
import static org.apache.iotdb.commons.pipe.config.constant.PipeConnectorConstant.SINK_IOTDB_BATCH_SIZE_KEY;

public abstract class PipeConsensusTransferBatchReqBuilder implements AutoCloseable {

  private static final Logger LOGGER =
      LoggerFactory.getLogger(PipeConsensusTransferBatchReqBuilder.class);

  protected final List<Event> events = new ArrayList<>();
  protected final List<Long> requestCommitIds = new ArrayList<>();
  protected final List<TPipeConsensusTransferReq> batchReqs = new ArrayList<>();
  // limit in delayed time
  protected final int maxDelayInMs;
  protected final TConsensusGroupId consensusGroupId;
  protected final int thisDataNodeId;
  protected long firstEventProcessingTime = Long.MIN_VALUE;

  // limit in buffer size
  protected final PipeMemoryBlock allocatedMemoryBlock;
  protected long totalBufferSize = 0;

  protected PipeConsensusTransferBatchReqBuilder(
      PipeParameters parameters, TConsensusGroupId consensusGroupId, int thisDataNodeId) {
    maxDelayInMs =
        parameters.getIntOrDefault(
                Arrays.asList(CONNECTOR_IOTDB_BATCH_DELAY_KEY, SINK_IOTDB_BATCH_DELAY_KEY),
                CONNECTOR_IOTDB_PLAIN_BATCH_DELAY_DEFAULT_VALUE)
            * 1000;

    this.consensusGroupId = consensusGroupId;
    this.thisDataNodeId = thisDataNodeId;

    final long requestMaxBatchSizeInBytes =
        parameters.getLongOrDefault(
            Arrays.asList(CONNECTOR_IOTDB_BATCH_SIZE_KEY, SINK_IOTDB_BATCH_SIZE_KEY),
            CONNECTOR_IOTDB_PLAIN_BATCH_SIZE_DEFAULT_VALUE);

    allocatedMemoryBlock =
        PipeDataNodeResourceManager.memory()
            .tryAllocate(requestMaxBatchSizeInBytes)
            .setShrinkMethod(oldMemory -> Math.max(oldMemory / 2, 0))
            .setShrinkCallback(
                (oldMemory, newMemory) ->
                    LOGGER.info(
                        "The batch size limit has shrunk from {} to {}.", oldMemory, newMemory))
            .setExpandMethod(
                oldMemory -> Math.min(Math.max(oldMemory, 1) * 2, requestMaxBatchSizeInBytes))
            .setExpandCallback(
                (oldMemory, newMemory) ->
                    LOGGER.info(
                        "The batch size limit has expanded from {} to {}.", oldMemory, newMemory));

    if (getMaxBatchSizeInBytes() != requestMaxBatchSizeInBytes) {
      LOGGER.info(
          "PipeConsensusTransferBatchReqBuilder: the max batch size is adjusted from {} to {} due to the "
              + "memory restriction",
          requestMaxBatchSizeInBytes,
          getMaxBatchSizeInBytes());
    }
  }

  /**
   * Try offer {@link Event} into cache if the given {@link Event} is not duplicated.
   *
   * @param event the given {@link Event}
   * @return {@link true} if the batch can be transferred
   */
  public synchronized boolean onEvent(TabletInsertionEvent event)
      throws IOException, WALPipeException {
    if (!(event instanceof EnrichedEvent)) {
      return false;
    }

    final long requestCommitId = ((EnrichedEvent) event).getReplicateIndexForIoTV2();

    // The deduplication logic here is to avoid the accumulation of the same event in a batch when
    // retrying.
    if ((events.isEmpty() || !events.get(events.size() - 1).equals(event))) {
      events.add(event);
      requestCommitIds.add(requestCommitId);
      final int bufferSize = buildTabletInsertionBuffer(event);

      ((EnrichedEvent) event)
          .increaseReferenceCount(PipeConsensusTransferBatchReqBuilder.class.getName());

      if (firstEventProcessingTime == Long.MIN_VALUE) {
        firstEventProcessingTime = System.currentTimeMillis();
      }

      totalBufferSize += bufferSize;
    }

    return totalBufferSize >= getMaxBatchSizeInBytes()
        || System.currentTimeMillis() - firstEventProcessingTime >= maxDelayInMs;
  }

  public synchronized void onSuccess() {
    batchReqs.clear();

    events.clear();
    requestCommitIds.clear();

    firstEventProcessingTime = Long.MIN_VALUE;

    totalBufferSize = 0;
  }

  public PipeConsensusTabletBatchReq toTPipeConsensusBatchTransferReq() throws IOException {
    return PipeConsensusTabletBatchReq.toTPipeConsensusBatchTransferReq(batchReqs);
  }

  protected long getMaxBatchSizeInBytes() {
    return allocatedMemoryBlock.getMemoryUsageInBytes();
  }

  public boolean isEmpty() {
    return batchReqs.isEmpty();
  }

  public List<Event> deepCopyEvents() {
    return new ArrayList<>(events);
  }

  protected int buildTabletInsertionBuffer(TabletInsertionEvent event) throws WALPipeException {
    final ByteBuffer buffer;
    final TCommitId commitId;

    // event instanceof PipeInsertNodeTabletInsertionEvent)
    final PipeInsertNodeTabletInsertionEvent pipeInsertNodeTabletInsertionEvent =
        (PipeInsertNodeTabletInsertionEvent) event;
    commitId =
        new TCommitId(
            pipeInsertNodeTabletInsertionEvent.getReplicateIndexForIoTV2(),
            pipeInsertNodeTabletInsertionEvent.getRebootTimes());

    // Read the bytebuffer from the wal file and transfer it directly without serializing or
    // deserializing if possible
    final InsertNode insertNode =
        pipeInsertNodeTabletInsertionEvent.getInsertNodeViaCacheIfPossible();
    // PipeConsensus will transfer binary data to TPipeConsensusTransferReq
    final ProgressIndex progressIndex = pipeInsertNodeTabletInsertionEvent.getProgressIndex();
    if (Objects.isNull(insertNode)) {
      buffer = pipeInsertNodeTabletInsertionEvent.getByteBuffer();
      batchReqs.add(
          PipeConsensusTabletBinaryReq.toTPipeConsensusTransferReq(
              buffer, commitId, consensusGroupId, progressIndex, thisDataNodeId));
    } else {
      buffer = insertNode.serializeToByteBuffer();
      batchReqs.add(
          PipeConsensusTabletInsertNodeReq.toTPipeConsensusTransferReq(
              insertNode, commitId, consensusGroupId, progressIndex, thisDataNodeId));
    }

    return buffer.limit();
  }

  @Override
  public synchronized void close() {
    for (final Event event : events) {
      if (event instanceof EnrichedEvent) {
        ((EnrichedEvent) event).clearReferenceCount(this.getClass().getName());
      }
    }
    allocatedMemoryBlock.close();
  }
}
