/*
 * 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.hudi.io;

import org.apache.hudi.common.model.HoodieBaseFile;
import org.apache.hudi.common.model.HoodieKey;
import org.apache.hudi.common.model.HoodieRecordGlobalLocation;
import org.apache.hudi.common.model.HoodieRecordLocation;
import org.apache.hudi.common.util.BaseFileUtils;
import org.apache.hudi.common.util.Option;
import org.apache.hudi.common.util.collection.Pair;
import org.apache.hudi.config.HoodieWriteConfig;
import org.apache.hudi.keygen.BaseKeyGenerator;
import org.apache.hudi.table.HoodieTable;

import org.apache.hadoop.fs.Path;

import java.util.List;
import java.util.stream.Stream;

/**
 * {@link HoodieRecordLocation} fetch handle for all records from {@link HoodieBaseFile} of interest.
 *
 * @param <T>
 */
public class HoodieKeyLocationFetchHandle<T, I, K, O> extends HoodieReadHandle<T, I, K, O> {

  private final Pair<String, HoodieBaseFile> partitionPathBaseFilePair;
  private final Option<BaseKeyGenerator> keyGeneratorOpt;

  public HoodieKeyLocationFetchHandle(HoodieWriteConfig config, HoodieTable<T, I, K, O> hoodieTable,
                                      Pair<String, HoodieBaseFile> partitionPathBaseFilePair, Option<BaseKeyGenerator> keyGeneratorOpt) {
    super(config, hoodieTable, Pair.of(partitionPathBaseFilePair.getLeft(), partitionPathBaseFilePair.getRight().getFileId()));
    this.partitionPathBaseFilePair = partitionPathBaseFilePair;
    this.keyGeneratorOpt = keyGeneratorOpt;
  }

  private List<HoodieKey> fetchHoodieKeys(HoodieBaseFile baseFile) {
    BaseFileUtils baseFileUtils = BaseFileUtils.getInstance(baseFile.getPath());
    if (keyGeneratorOpt.isPresent()) {
      return baseFileUtils.fetchHoodieKeys(hoodieTable.getHadoopConf(), new Path(baseFile.getPath()), keyGeneratorOpt);
    } else {
      return baseFileUtils.fetchHoodieKeys(hoodieTable.getHadoopConf(), new Path(baseFile.getPath()));
    }
  }

  public Stream<Pair<HoodieKey, HoodieRecordLocation>> locations() {
    HoodieBaseFile baseFile = partitionPathBaseFilePair.getRight();
    String commitTime = baseFile.getCommitTime();
    String fileId = baseFile.getFileId();
    return fetchHoodieKeys(baseFile).stream()
        .map(entry -> Pair.of(entry,
            new HoodieRecordLocation(commitTime, fileId)));
  }

  public Stream<Pair<String, HoodieRecordGlobalLocation>> globalLocations() {
    HoodieBaseFile baseFile = partitionPathBaseFilePair.getRight();
    return fetchHoodieKeys(baseFile).stream()
        .map(entry -> Pair.of(entry.getRecordKey(),
            new HoodieRecordGlobalLocation(entry.getPartitionPath(), baseFile.getCommitTime(), baseFile.getFileId())));
  }
}
