/*
 * 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.queryengine.execution.fragment;

import org.apache.iotdb.commons.path.PartialPath;
import org.apache.iotdb.db.exception.query.QueryProcessException;
import org.apache.iotdb.db.queryengine.plan.planner.memory.FakedMemoryReservationManager;
import org.apache.iotdb.db.storageengine.dataregion.DataRegion;
import org.apache.iotdb.db.storageengine.dataregion.read.QueryDataSource;
import org.apache.iotdb.db.storageengine.dataregion.read.control.FileReaderManager;
import org.apache.iotdb.db.storageengine.dataregion.tsfile.TsFileResource;

import org.apache.tsfile.read.filter.basic.Filter;

import java.util.Collections;
import java.util.List;

public class FakedFragmentInstanceContext extends FragmentInstanceContext {

  public FakedFragmentInstanceContext(Filter timeFilter, DataRegion dataRegion) {
    super(0, new FakedMemoryReservationManager(), timeFilter, dataRegion);
  }

  public QueryDataSource getSharedQueryDataSource(PartialPath sourcePath)
      throws QueryProcessException {
    if (sharedQueryDataSource == null) {
      initQueryDataSource(sourcePath);
    }
    return (QueryDataSource) sharedQueryDataSource;
  }

  public void initQueryDataSource(PartialPath sourcePath) throws QueryProcessException {

    dataRegion.tryReadLock(Long.MAX_VALUE);
    try {
      this.sharedQueryDataSource =
          dataRegion.query(
              Collections.singletonList(sourcePath),
              sourcePath.getDevice(),
              this,
              getGlobalTimeFilter(),
              null,
              Long.MAX_VALUE);

      // used files should be added before mergeLock is unlocked, or they may be deleted by
      // running merge
      if (sharedQueryDataSource != null) {
        ((QueryDataSource) sharedQueryDataSource).setSingleDevice(true);
        List<TsFileResource> tsFileList =
            ((QueryDataSource) sharedQueryDataSource).getSeqResources();
        if (tsFileList != null) {
          for (TsFileResource tsFile : tsFileList) {
            FileReaderManager.getInstance().increaseFileReaderReference(tsFile, tsFile.isClosed());
          }
        }
        tsFileList = ((QueryDataSource) sharedQueryDataSource).getUnseqResources();
        if (tsFileList != null) {
          for (TsFileResource tsFile : tsFileList) {
            FileReaderManager.getInstance().increaseFileReaderReference(tsFile, tsFile.isClosed());
          }
        }
      }
    } finally {
      dataRegion.readUnlock();
    }
  }

  public void releaseSharedQueryDataSource() {
    if (sharedQueryDataSource != null) {
      List<TsFileResource> tsFileList = ((QueryDataSource) sharedQueryDataSource).getSeqResources();
      if (tsFileList != null) {
        for (TsFileResource tsFile : tsFileList) {
          FileReaderManager.getInstance().decreaseFileReaderReference(tsFile, tsFile.isClosed());
        }
      }
      tsFileList = ((QueryDataSource) sharedQueryDataSource).getUnseqResources();
      if (tsFileList != null) {
        for (TsFileResource tsFile : tsFileList) {
          FileReaderManager.getInstance().decreaseFileReaderReference(tsFile, tsFile.isClosed());
        }
      }
      sharedQueryDataSource = null;
    }
  }

  @Override
  protected boolean checkIfModificationExists(TsFileResource tsFileResource) {
    return false;
  }
}
