/**
 * 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.hbase.mapreduce;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;

import java.io.IOException;
import java.util.ArrayList;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseTestingUtility;
import org.apache.hadoop.hbase.MediumTests;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.hbase.mapreduce.RowCounter.RowCounterMapper;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.mapreduce.Counter;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.util.GenericOptionsParser;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;
import org.junit.experimental.categories.Category;

/**
 * Test the rowcounter map reduce job.
 */
@Category(MediumTests.class)
public class TestRowCounter {
  final Log LOG = LogFactory.getLog(getClass());
  private final static HBaseTestingUtility TEST_UTIL = new HBaseTestingUtility();
  private final static String TABLE_NAME = "testRowCounter";
  private final static String COL_FAM = "col_fam";
  private final static String COL1 = "c1";
  private final static String COL2 = "c2";
  private final static int TOTAL_ROWS = 10;
  private final static int ROWS_WITH_ONE_COL = 2;

  /**
   * @throws java.lang.Exception
   */
  @BeforeClass
  public static void setUpBeforeClass() throws Exception {
    TEST_UTIL.startMiniCluster();
    TEST_UTIL.startMiniMapReduceCluster();
    HTable table = TEST_UTIL.createTable(Bytes.toBytes(TABLE_NAME),
        Bytes.toBytes(COL_FAM));
    writeRows(table);
    table.close();
  }

  /**
   * @throws java.lang.Exception
   */
  @AfterClass
  public static void tearDownAfterClass() throws Exception {
    TEST_UTIL.shutdownMiniCluster();
    TEST_UTIL.shutdownMiniMapReduceCluster();
  }

  /**
   * Test a case when no column was specified in command line arguments.
   * 
   * @throws Exception
   */
  @Test
  public void testRowCounterNoColumn() throws Exception {
    String[] args = new String[] {
        TABLE_NAME
    };
    runRowCount(args, 10);
  }

  /**
   * Test a case when the column specified in command line arguments is
   * exclusive for few rows.
   * 
   * @throws Exception
   */
  @Test
  public void testRowCounterExclusiveColumn() throws Exception {
    String[] args = new String[] {
        TABLE_NAME, COL_FAM + ":" + COL1
    };
    runRowCount(args, 8);
  }

  /**
   * Test a case when the column specified in command line arguments is not part
   * of first KV for a row.
   * 
   * @throws Exception
   */
  @Test
  public void testRowCounterHiddenColumn() throws Exception {
    String[] args = new String[] {
        TABLE_NAME, COL_FAM + ":" + COL2
    };
    runRowCount(args, 10);
  }

  /**
   * Run the RowCounter map reduce job and verify the row count.
   * 
   * @param args the command line arguments to be used for rowcounter job.
   * @param expectedCount the expected row count (result of map reduce job).
   * @throws Exception
   */
  private void runRowCount(String[] args, int expectedCount) throws Exception {
    GenericOptionsParser opts = new GenericOptionsParser(
        TEST_UTIL.getConfiguration(), args);
    Configuration conf = opts.getConfiguration();
    args = opts.getRemainingArgs();
    Job job = RowCounter.createSubmittableJob(conf, args);
    job.waitForCompletion(true);
    assertTrue(job.isSuccessful());
    Counter counter = job.getCounters().findCounter(
        RowCounterMapper.Counters.ROWS);
    assertEquals(expectedCount, counter.getValue());
  }

  /**
   * Writes TOTAL_ROWS number of distinct rows in to the table. Few rows have
   * two columns, Few have one.
   * 
   * @param table
   * @throws IOException
   */
  private static void writeRows(HTable table) throws IOException {
    final byte[] family = Bytes.toBytes(COL_FAM);
    final byte[] value = Bytes.toBytes("abcd");
    final byte[] col1 = Bytes.toBytes(COL1);
    final byte[] col2 = Bytes.toBytes(COL2);
    ArrayList<Put> rowsUpdate = new ArrayList<Put>();
    // write few rows with two columns
    int i = 0;
    for (; i < TOTAL_ROWS - ROWS_WITH_ONE_COL; i++) {
      byte[] row = Bytes.toBytes("row" + i);
      Put put = new Put(row);
      put.add(family, col1, value);
      put.add(family, col2, value);
      rowsUpdate.add(put);
    }

    // write few rows with only one column
    for (; i < TOTAL_ROWS; i++) {
      byte[] row = Bytes.toBytes("row" + i);
      Put put = new Put(row);
      put.add(family, col2, value);
      rowsUpdate.add(put);
    }
    table.put(rowsUpdate);
  }
}