/**
    *
    * 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 java.io.IOException;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.hbase.HConstants;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.classification.InterfaceStability;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.hbase.Cell;
  import org.apache.hadoop.hbase.CellUtil;
  import org.apache.hadoop.hbase.HBaseConfiguration;
  import org.apache.hadoop.hbase.client.Result;
  import org.apache.hadoop.hbase.client.Scan;
  import org.apache.hadoop.hbase.filter.CompareFilter;
  import org.apache.hadoop.hbase.filter.Filter;
  import org.apache.hadoop.hbase.filter.PrefixFilter;
  import org.apache.hadoop.hbase.filter.RegexStringComparator;
  import org.apache.hadoop.hbase.filter.RowFilter;
  import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
  import org.apache.hadoop.hbase.util.Bytes;
  import org.apache.hadoop.io.IntWritable;
  import org.apache.hadoop.io.Text;
  import org.apache.hadoop.mapreduce.Job;
  import org.apache.hadoop.mapreduce.Reducer;
  import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
  import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;
  import org.apache.hadoop.util.GenericOptionsParser;
  
  import com.google.common.base.Preconditions;
  
  
  /**
   * A job with a a map and reduce phase to count cells in a table.
   * The counter lists the following stats for a given table:
   * <pre>
   * 1. Total number of rows in the table
   * 2. Total number of CFs across all rows
   * 3. Total qualifiers across all rows
   * 4. Total occurrence of each CF
   * 5. Total occurrence  of each qualifier
   * 6. Total number of versions of each qualifier.
   * </pre>
   *
   * The cellcounter takes two optional parameters one to use a user
   * supplied row/family/qualifier string to use in the report and
   * second a regex based or prefix based row filter to restrict the
   * count operation to a limited subset of rows from the table.
   */
  @InterfaceAudience.Public
  @InterfaceStability.Stable
  public class CellCounter {
    private static final Log LOG =
      LogFactory.getLog(CellCounter.class.getName());
  
  
    /**
     * Name of this 'program'.
     */
    static final String NAME = "CellCounter";
  
    /**
     * Mapper that runs the count.
     */
    static class CellCounterMapper
    extends TableMapper<Text, IntWritable> {
      /**
       * Counter enumeration to count the actual rows.
       */
      public static enum Counters {
        ROWS,
        CELLS
      }
  
      private Configuration conf;
      private String separator;
  
      // state of current row, family, column needs to persist across map() invocations
      // in order to properly handle scanner batching, where a single qualifier may have too
     // many versions for a single map() call
     private byte[] lastRow;
     private String currentRowKey;
     byte[] currentFamily = null;
     String currentFamilyName = null;
     byte[] currentQualifier = null;
     // family + qualifier
     String currentQualifierName = null;
     // rowkey + family + qualifier
     String currentRowQualifierName = null;
 
     @Override
     protected void setup(Context context) throws IOException, InterruptedException {
       conf = context.getConfiguration();
       separator = conf.get("ReportSeparator",":");
     }
 
     /**
      * Maps the data.
      *
      * @param row     The current table row key.
      * @param values  The columns.
      * @param context The current context.
      * @throws IOException When something is broken with the data.
      * @see org.apache.hadoop.mapreduce.Mapper#map(KEYIN, VALUEIN,
      *      org.apache.hadoop.mapreduce.Mapper.Context)
      */
 
     @Override
     @edu.umd.cs.findbugs.annotations.SuppressWarnings(value="NP_NULL_ON_SOME_PATH",
       justification="Preconditions checks insure we are not going to dereference a null value")
     public void map(ImmutableBytesWritable row, Result values,
                     Context context)
         throws IOException {
       Preconditions.checkState(values != null,
           "values passed to the map is null");
       try {
         byte[] currentRow = values.getRow();
         if (lastRow == null || !Bytes.equals(lastRow, currentRow)) {
           lastRow = currentRow;
           currentRowKey = Bytes.toStringBinary(currentRow);
           currentFamily = null;
           currentQualifier = null;
           context.getCounter(Counters.ROWS).increment(1);
           context.write(new Text("Total ROWS"), new IntWritable(1));
         }
         if (!values.isEmpty()) {
           int cellCount = 0;
           for (Cell value : values.listCells()) {
             cellCount++;
             if (currentFamily == null || !CellUtil.matchingFamily(value, currentFamily)) {
               currentFamily = CellUtil.cloneFamily(value);
               currentFamilyName = Bytes.toStringBinary(currentFamily);
               currentQualifier = null;
               context.getCounter("CF", currentFamilyName).increment(1);
               if (1 == context.getCounter("CF", currentFamilyName).getValue()) {
                 context.write(new Text("Total Families Across all Rows"), new IntWritable(1));
                 context.write(new Text(currentFamily), new IntWritable(1));
               }
             }
             if (currentQualifier == null || !CellUtil.matchingQualifier(value, currentQualifier)) {
               currentQualifier = CellUtil.cloneQualifier(value);
               currentQualifierName = currentFamilyName + separator +
                   Bytes.toStringBinary(currentQualifier);
               currentRowQualifierName = currentRowKey + separator + currentQualifierName;
 
               context.write(new Text("Total Qualifiers across all Rows"),
                   new IntWritable(1));
               context.write(new Text(currentQualifierName), new IntWritable(1));
             }
             // Increment versions
             context.write(new Text(currentRowQualifierName + "_Versions"), new IntWritable(1));
           }
           context.getCounter(Counters.CELLS).increment(cellCount);
         }
       } catch (InterruptedException e) {
         e.printStackTrace();
       }
     }
   }
 
   static class IntSumReducer<Key> extends Reducer<Key, IntWritable,
       Key, IntWritable> {
     private IntWritable result = new IntWritable();
 
     @Override
     public void reduce(Key key, Iterable<IntWritable> values, Context context)
     throws IOException, InterruptedException {
       int sum = 0;
       for (IntWritable val : values) {
         sum += val.get();
       }
       result.set(sum);
       context.write(key, result);
     }
   }
 
   /**
    * Sets up the actual job.
    *
    * @param conf The current configuration.
    * @param args The command line parameters.
    * @return The newly created job.
    * @throws IOException When setting up the job fails.
    */
   public static Job createSubmittableJob(Configuration conf, String[] args)
       throws IOException {
     String tableName = args[0];
     Path outputDir = new Path(args[1]);
     String reportSeparatorString = (args.length > 2) ? args[2]: ":";
     conf.set("ReportSeparator", reportSeparatorString);
     Job job = new Job(conf, NAME + "_" + tableName);
     job.setJarByClass(CellCounter.class);
     Scan scan = getConfiguredScanForJob(conf, args);
     TableMapReduceUtil.initTableMapperJob(tableName, scan,
         CellCounterMapper.class, ImmutableBytesWritable.class, Result.class, job);
     job.setNumReduceTasks(1);
     job.setMapOutputKeyClass(Text.class);
     job.setMapOutputValueClass(IntWritable.class);
     job.setOutputFormatClass(TextOutputFormat.class);
     job.setOutputKeyClass(Text.class);
     job.setOutputValueClass(IntWritable.class);
     FileOutputFormat.setOutputPath(job, outputDir);
     job.setReducerClass(IntSumReducer.class);
     return job;
   }
 
   private static Scan getConfiguredScanForJob(Configuration conf, String[] args)
       throws IOException {
     // create scan with any properties set from TableInputFormat
     Scan s = TableInputFormat.createScanFromConfiguration(conf);
     // Set Scan Versions
     if (conf.get(TableInputFormat.SCAN_MAXVERSIONS) == null) {
       // default to all versions unless explicitly set
       s.setMaxVersions(Integer.MAX_VALUE);
     }
     s.setCacheBlocks(false);
     // Set RowFilter or Prefix Filter if applicable.
     Filter rowFilter = getRowFilter(args);
     if (rowFilter!= null) {
       LOG.info("Setting Row Filter for counter.");
       s.setFilter(rowFilter);
     }
     // Set TimeRange if defined
     long timeRange[] = getTimeRange(args);
     if (timeRange != null) {
       LOG.info("Setting TimeRange for counter.");
       s.setTimeRange(timeRange[0], timeRange[1]);
     }
     return s;
   }
 
 
   private static Filter getRowFilter(String[] args) {
     Filter rowFilter = null;
     String filterCriteria = (args.length > 3) ? args[3]: null;
     if (filterCriteria == null) return null;
     if (filterCriteria.startsWith("^")) {
       String regexPattern = filterCriteria.substring(1, filterCriteria.length());
       rowFilter = new RowFilter(CompareFilter.CompareOp.EQUAL, new RegexStringComparator(regexPattern));
     } else {
       rowFilter = new PrefixFilter(Bytes.toBytesBinary(filterCriteria));
     }
     return rowFilter;
   }
 
   private static long[] getTimeRange(String[] args) throws IOException {
     final String startTimeArgKey = "--starttime=";
     final String endTimeArgKey = "--endtime=";
     long startTime = 0L;
     long endTime = 0L;
 
     for (int i = 1; i < args.length; i++) {
       System.out.println("i:" + i + "arg[i]" + args[i]);
       if (args[i].startsWith(startTimeArgKey)) {
         startTime = Long.parseLong(args[i].substring(startTimeArgKey.length()));
       }
       if (args[i].startsWith(endTimeArgKey)) {
         endTime = Long.parseLong(args[i].substring(endTimeArgKey.length()));
       }
     }
 
     if (startTime == 0 && endTime == 0)
       return null;
 
     endTime = endTime == 0 ? HConstants.LATEST_TIMESTAMP : endTime;
     return new long [] {startTime, endTime};
   }
   /**
    * Main entry point.
    *
    * @param args The command line parameters.
    * @throws Exception When running the job fails.
    */
   public static void main(String[] args) throws Exception {
     Configuration conf = HBaseConfiguration.create();
     String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs();
     if (otherArgs.length < 2) {
       System.err.println("ERROR: Wrong number of parameters: " + args.length);
       System.err.println("Usage: CellCounter ");
       System.err.println("       <tablename> <outputDir> <reportSeparator> [^[regex pattern] or " +
         "[Prefix] for row filter]] --starttime=[starttime] --endtime=[endtime]");
       System.err.println("  Note: -D properties will be applied to the conf used. ");
       System.err.println("  Additionally, all of the SCAN properties from TableInputFormat");
       System.err.println("  can be specified to get fine grained control on what is counted..");
       System.err.println("   -D " + TableInputFormat.SCAN_ROW_START + "=<rowkey>");
       System.err.println("   -D " + TableInputFormat.SCAN_ROW_STOP + "=<rowkey>");
       System.err.println("   -D " + TableInputFormat.SCAN_COLUMNS + "=\"<col1> <col2>...\"");
       System.err.println("   -D " + TableInputFormat.SCAN_COLUMN_FAMILY + "=<familyName>");
       System.err.println("   -D " + TableInputFormat.SCAN_TIMESTAMP + "=<timestamp>");
       System.err.println("   -D " + TableInputFormat.SCAN_TIMERANGE_START + "=<timestamp>");
       System.err.println("   -D " + TableInputFormat.SCAN_TIMERANGE_END + "=<timestamp>");
       System.err.println("   -D " + TableInputFormat.SCAN_MAXVERSIONS + "=<count>");
       System.err.println("   -D " + TableInputFormat.SCAN_CACHEDROWS + "=<count>");
       System.err.println("   -D " + TableInputFormat.SCAN_BATCHSIZE + "=<count>");
       System.err.println(" <reportSeparator> parameter can be used to override the default report separator " +
           "string : used to separate the rowId/column family name and qualifier name.");
       System.err.println(" [^[regex pattern] or [Prefix] parameter can be used to limit the cell counter count " +
           "operation to a limited subset of rows from the table based on regex or prefix pattern.");
       System.exit(-1);
     }
     Job job = createSubmittableJob(conf, otherArgs);
     System.exit(job.waitForCompletion(true) ? 0 : 1);
   }
 }