/**
    * 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.File;
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Locale;
  import java.util.Map;
  import java.util.NavigableMap;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.fs.FileUtil;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.hbase.HBaseTestingUtility;
  import org.apache.hadoop.hbase.testclassification.LargeTests;
  import org.apache.hadoop.hbase.TableName;
  import org.apache.hadoop.hbase.client.HTable;
  import org.apache.hadoop.hbase.client.Result;
  import org.apache.hadoop.hbase.client.Scan;
  import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
  import org.apache.hadoop.hbase.util.Bytes;
  import org.apache.hadoop.io.NullWritable;
  import org.apache.hadoop.mapreduce.Job;
  import org.apache.hadoop.mapreduce.Reducer;
  import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
  import org.junit.After;
  import org.junit.AfterClass;
  import org.junit.BeforeClass;
  import org.junit.Test;
  import org.junit.experimental.categories.Category;
  
  /**
   * Tests various scan start and stop row scenarios. This is set in a scan and
   * tested in a MapReduce job to see if that is handed over and done properly
   * too.
   */
  @Category(LargeTests.class)
  public class TestMultiTableInputFormat {
  
    private static final Log LOG = LogFactory.getLog(TestMultiTableInputFormat.class);
    static final HBaseTestingUtility TEST_UTIL = new HBaseTestingUtility();
  
    static final String TABLE_NAME = "scantest";
    static final byte[] INPUT_FAMILY = Bytes.toBytes("contents");
    static final String KEY_STARTROW = "startRow";
    static final String KEY_LASTROW = "stpRow";
  
    @BeforeClass
    public static void setUpBeforeClass() throws Exception {
      // switch TIF to log at DEBUG level
      TEST_UTIL.enableDebug(MultiTableInputFormat.class);
      TEST_UTIL.enableDebug(MultiTableInputFormatBase.class);
      TEST_UTIL.setJobWithoutMRCluster();
      // start mini hbase cluster
      TEST_UTIL.startMiniCluster(3);
      // create and fill table
      for (int i = 0; i < 3; i++) {
        try (HTable table =
            TEST_UTIL.createMultiRegionTable(TableName.valueOf(TABLE_NAME + String.valueOf(i)),
              INPUT_FAMILY, 4)) {
          TEST_UTIL.loadTable(table, INPUT_FAMILY, false);
        }
      }
    }
  
    @AfterClass
    public static void tearDownAfterClass() throws Exception {
      TEST_UTIL.shutdownMiniCluster();
    }
    
    @After
    public void tearDown() throws Exception {
      Configuration c = TEST_UTIL.getConfiguration();
      FileUtil.fullyDelete(new File(c.get("hadoop.tmp.dir")));
    }
  
    /**
    * Pass the key and value to reducer.
    */
   public static class ScanMapper extends
       TableMapper<ImmutableBytesWritable, ImmutableBytesWritable> {
     /**
      * Pass the key and value to reduce.
      *
      * @param key The key, here "aaa", "aab" etc.
      * @param value The value is the same as the key.
      * @param context The task context.
      * @throws IOException When reading the rows fails.
      */
     @Override
     public void map(ImmutableBytesWritable key, Result value, Context context)
         throws IOException, InterruptedException {
       if (value.size() != 1) {
         throw new IOException("There should only be one input column");
       }
       Map<byte[], NavigableMap<byte[], NavigableMap<Long, byte[]>>> cf =
           value.getMap();
       if (!cf.containsKey(INPUT_FAMILY)) {
         throw new IOException("Wrong input columns. Missing: '" +
             Bytes.toString(INPUT_FAMILY) + "'.");
       }
       String val = Bytes.toStringBinary(value.getValue(INPUT_FAMILY, null));
       LOG.debug("map: key -> " + Bytes.toStringBinary(key.get()) +
           ", value -> " + val);
       context.write(key, key);
     }
   }
 
   /**
    * Checks the last and first keys seen against the scanner boundaries.
    */
   public static class ScanReducer
       extends
       Reducer<ImmutableBytesWritable, ImmutableBytesWritable,
       NullWritable, NullWritable> {
     private String first = null;
     private String last = null;
 
     @Override
     protected void reduce(ImmutableBytesWritable key,
         Iterable<ImmutableBytesWritable> values, Context context)
         throws IOException, InterruptedException {
       int count = 0;
       for (ImmutableBytesWritable value : values) {
         String val = Bytes.toStringBinary(value.get());
         LOG.debug("reduce: key[" + count + "] -> " +
             Bytes.toStringBinary(key.get()) + ", value -> " + val);
         if (first == null) first = val;
         last = val;
         count++;
       }
       assertEquals(3, count);
     }
 
     @Override
     protected void cleanup(Context context) throws IOException,
         InterruptedException {
       Configuration c = context.getConfiguration();
       String startRow = c.get(KEY_STARTROW);
       String lastRow = c.get(KEY_LASTROW);
       LOG.info("cleanup: first -> \"" + first + "\", start row -> \"" +
           startRow + "\"");
       LOG.info("cleanup: last -> \"" + last + "\", last row -> \"" + lastRow +
           "\"");
       if (startRow != null && startRow.length() > 0) {
         assertEquals(startRow, first);
       }
       if (lastRow != null && lastRow.length() > 0) {
         assertEquals(lastRow, last);
       }
     }
   }
 
   @Test
   public void testScanEmptyToEmpty() throws IOException, InterruptedException,
       ClassNotFoundException {
     testScan(null, null, null);
   }
   
   @Test
   public void testScanEmptyToAPP() throws IOException, InterruptedException,
       ClassNotFoundException {
     testScan(null, "app", "apo");
   }
 
   @Test
   public void testScanOBBToOPP() throws IOException, InterruptedException,
       ClassNotFoundException {
     testScan("obb", "opp", "opo");
   }
 
   @Test
   public void testScanYZYToEmpty() throws IOException, InterruptedException,
       ClassNotFoundException {
     testScan("yzy", null, "zzz");
   }
 
   /**
    * Tests a MR scan using specific start and stop rows.
    *
    * @throws IOException
    * @throws ClassNotFoundException
    * @throws InterruptedException
    */
   private void testScan(String start, String stop, String last)
       throws IOException, InterruptedException, ClassNotFoundException {
     String jobName =
         "Scan" + (start != null ? start.toUpperCase(Locale.ROOT) : "Empty") + "To" +
             (stop != null ? stop.toUpperCase(Locale.ROOT) : "Empty");
     LOG.info("Before map/reduce startup - job " + jobName);
     Configuration c = new Configuration(TEST_UTIL.getConfiguration());
     
     c.set(KEY_STARTROW, start != null ? start : "");
     c.set(KEY_LASTROW, last != null ? last : "");
     
     List<Scan> scans = new ArrayList<Scan>();
     
     for(int i=0; i<3; i++){
       Scan scan = new Scan();
       
       scan.addFamily(INPUT_FAMILY);
       scan.setAttribute(Scan.SCAN_ATTRIBUTES_TABLE_NAME, Bytes.toBytes(TABLE_NAME + i));
       
       if (start != null) {
         scan.setStartRow(Bytes.toBytes(start));
       }
       if (stop != null) {
         scan.setStopRow(Bytes.toBytes(stop));
       }
       
       scans.add(scan);
       
       LOG.info("scan before: " + scan);
     }
     
     Job job = new Job(c, jobName);
 
     TableMapReduceUtil.initTableMapperJob(scans, ScanMapper.class,
         ImmutableBytesWritable.class, ImmutableBytesWritable.class, job);
     job.setReducerClass(ScanReducer.class);
     job.setNumReduceTasks(1); // one to get final "first" and "last" key
     FileOutputFormat.setOutputPath(job,
       new Path(TEST_UTIL.getDataTestDirOnTestFS(), job.getJobName()));
     LOG.info("Started " + job.getJobName());
     job.waitForCompletion(true);
     assertTrue(job.isSuccessful());
     LOG.info("After map/reduce completion - job " + jobName);
   }
 }