/**
 * 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.hive.hbase;

import java.io.IOException;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.client.Durability;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.hadoop.hbase.mapred.TableMapReduceUtil;
import org.apache.hadoop.hbase.mapreduce.TableOutputCommitter;
import org.apache.hadoop.hbase.mapreduce.TableOutputFormat;
import org.apache.hadoop.hive.conf.HiveConf;
import org.apache.hadoop.hive.hbase.PutWritable;
import org.apache.hadoop.hive.shims.ShimLoader;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.OutputFormat;
import org.apache.hadoop.mapred.Reporter;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.JobContext;
import org.apache.hadoop.mapreduce.OutputCommitter;
import org.apache.hadoop.mapreduce.TaskAttemptContext;
import org.apache.hadoop.util.Progressable;
import org.apache.hadoop.security.UserGroupInformation;

/**
 * HiveHBaseTableOutputFormat implements HiveOutputFormat for HBase tables.
 * We also need to implement the @deprecated org.apache.hadoop.mapred.OutFormat<?,?>
 * class to keep it compliant with Hive interfaces.
 */
public class HiveHBaseTableOutputFormat extends
    TableOutputFormat<ImmutableBytesWritable> implements
    OutputFormat<ImmutableBytesWritable, Object> {

  static final Logger LOG = LoggerFactory.getLogger(HiveHBaseTableOutputFormat.class);
  public static final String HBASE_WAL_ENABLED = "hive.hbase.wal.enabled";

  /**
   * Update the out table, and output an empty key as the key.
   *
   * @param jc the job configuration file
   * @param finalOutPath the final output table name
   * @param valueClass the value class
   * @param isCompressed whether the content is compressed or not
   * @param tableProperties the table info of the corresponding table
   * @param progress progress used for status report
   * @return the RecordWriter for the output file
   */


  @Override
  public void checkOutputSpecs(FileSystem fs, JobConf jc) throws IOException {

    //obtain delegation tokens for the job
    if (UserGroupInformation.getCurrentUser().hasKerberosCredentials()) {
      TableMapReduceUtil.initCredentials(jc);
    }

    String hbaseTableName = jc.get(HBaseSerDe.HBASE_TABLE_NAME);
    jc.set(TableOutputFormat.OUTPUT_TABLE, hbaseTableName);
    Job job = new Job(jc);
    JobContext jobContext = ShimLoader.getHadoopShims().newJobContext(job);

    try {
      checkOutputSpecs(jobContext);
    } catch (InterruptedException e) {
      throw new IOException(e);
    }
  }

  @Override
  public
  org.apache.hadoop.mapred.RecordWriter<ImmutableBytesWritable, Object>
  getRecordWriter(
      FileSystem fileSystem,
      JobConf jobConf,
      String name,
      Progressable progressable) throws IOException {

    String hbaseTableName = jobConf.get(HBaseSerDe.HBASE_TABLE_NAME);
    jobConf.set(TableOutputFormat.OUTPUT_TABLE, hbaseTableName);
    final boolean walEnabled = HiveConf.getBoolVar(
        jobConf, HiveConf.ConfVars.HIVE_HBASE_WAL_ENABLED);
    final HTable table = new HTable(HBaseConfiguration.create(jobConf), hbaseTableName);
    table.setAutoFlush(false);
    return new MyRecordWriter(table,walEnabled);
  }

  @Override
  public OutputCommitter getOutputCommitter(TaskAttemptContext context) throws IOException,
  InterruptedException {
    return new TableOutputCommitter();
  }


  static private class MyRecordWriter implements org.apache.hadoop.mapred.RecordWriter<ImmutableBytesWritable, Object> {
    private final HTable m_table;
    private final boolean m_walEnabled;

    public MyRecordWriter(HTable table, boolean walEnabled) {
      m_table = table;
      m_walEnabled = walEnabled;
    }

    public void close(Reporter reporter)
      throws IOException {
      m_table.close();
    }

    public void write(ImmutableBytesWritable key,
        Object value) throws IOException {
      Put put;
      if (value instanceof Put){
        put = (Put)value;
      } else if (value instanceof PutWritable) {
        put = new Put(((PutWritable)value).getPut());
      } else {
        throw new IllegalArgumentException("Illegal Argument " + (value == null ? "null" : value.getClass().getName()));
      }
      if(m_walEnabled) {
        put.setDurability(Durability.SYNC_WAL);
      } else {
        put.setDurability(Durability.SKIP_WAL);
      }
      m_table.put(put);
    }

    @Override
    protected void finalize() throws Throwable {
      try {
        m_table.close();
      } finally {
        super.finalize();
      }
    }
  }
}