/*
    * 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.chukwa.extraction.demux.processor.mapper;
  
  
  import java.io.IOException;
  import java.text.ParseException;
  import java.text.SimpleDateFormat;
  import java.util.Date;
  import java.util.Map;
  import java.util.HashMap;
  import java.util.regex.Pattern;
  import java.util.regex.Matcher;
  
  import org.apache.hadoop.chukwa.datacollection.writer.hbase.Annotation.Table;
  import org.apache.hadoop.chukwa.extraction.engine.ChukwaRecord;
  import org.apache.hadoop.chukwa.extraction.engine.ChukwaRecordKey;
  import org.apache.hadoop.chukwa.extraction.demux.Demux;
  import org.apache.hadoop.mapred.OutputCollector;
  import org.apache.hadoop.mapred.Reporter;
  import org.apache.hadoop.mapred.JobConf;
  import org.apache.log4j.Logger;
  
  /**
   * TsProcessor is a generic processor that can be configured to find the timestamp
   * in the text of a record. By default, this class expects that a record
   * starts with a date in this format: <code>yyyy-MM-dd HH:mm:ss,SSS</code>
   * <P>
   * This format can be changed with the following configurations.
   * <UL>
   * <LI><code>TsProcessor.default.time.format</code> - Changes the default time
   * format used by all data types.</LI>
   * <LI><code>TsProcessor.time.format.[some_data_type]</code> - Overrides the default
   * format for a specific data type.</LI>
   * </UL>
   * If the time string is not at the beginning of the record you can configure a
   * regular expression to locate the timestamp text with either of the following
   * configurations. The text found in group 1 of the regular expression match
   * will be used with the configured date format.
   * <UL>
   * <LI><code>TsProcessor.default.time.regex</code> - Changes the default time
   * location regex of the time text for all data types.</LI>
   * <LI><code>TsProcessor.time.regex.[some_data_type]</code> - Overrides the
   * default time location regex for a specific data type.</LI>
   * </UL>
   *
   */
  @Table(name="TsProcessor",columnFamily="log")
  public class TsProcessor extends AbstractProcessor {
    static Logger log = Logger.getLogger(TsProcessor.class);
  
    public static final String DEFAULT_DATE_FORMAT = "yyyy-MM-dd HH:mm:ss,SSS";
  
    private Map<String, Pattern> datePatternMap;
    private Map<String, SimpleDateFormat> dateFormatMap;
  
    public TsProcessor() {
      datePatternMap = new HashMap<String, Pattern>();
      dateFormatMap = new HashMap<String, SimpleDateFormat>();
    }
  
    @Override
    protected void parse(String recordEntry,
        OutputCollector<ChukwaRecordKey, ChukwaRecord> output, Reporter reporter)
        throws Throwable {
      try {
        SimpleDateFormat sdf = fetchDateFormat(chunk.getDataType());
        Pattern datePattern = fetchDateLocationPattern(chunk.getDataType());
        String dStr = null;
  
        // fetch the part of the record that contains the date.
        if(datePattern != null) {
          Matcher m = datePattern.matcher(recordEntry);
          if (!m.matches() || m.groupCount() < 1) {
            throw new ParseException("Regex " + datePattern +
                    " couldn't extract date string from record: " + recordEntry, 0);
          }
          else {
            dStr = m.group(1);
          }
        }
        else {
          dStr = recordEntry;
        }
 
       Date d = sdf.parse(dStr);
       ChukwaRecord record = new ChukwaRecord();
       this.buildGenericRecord(record, recordEntry, d.getTime(), chunk
           .getDataType());
       output.collect(key, record);
     } catch (ParseException e) {
       log.warn("Unable to parse the date in DefaultProcessor [" + recordEntry
           + "]", e);
       e.printStackTrace();
       throw e;
     } catch (IOException e) {
       log.warn("Unable to collect output in DefaultProcessor [" + recordEntry
           + "]", e);
       e.printStackTrace();
       throw e;
     }
 
   }
   
   /**
    * For a given dataType, returns the SimpeDateFormat to use.
    * @param dataType
    * @return
    */
   private SimpleDateFormat fetchDateFormat(String dataType) {
     if (dateFormatMap.get(dataType) != null) {
       return dateFormatMap.get(dataType);
     }
 
     JobConf jobConf = Demux.jobConf;
     String dateFormat = DEFAULT_DATE_FORMAT;
 
     if (jobConf != null) {
       dateFormat = jobConf.get("TsProcessor.default.time.format", dateFormat);
       dateFormat = jobConf.get("TsProcessor.time.format." + chunk.getDataType(),
                                dateFormat);
     }
 
     SimpleDateFormat sdf = new SimpleDateFormat(dateFormat);
     dateFormatMap.put(dataType, sdf);
 
     return sdf;
   }
 
   /**
    * For a given dataType, returns a Pattern that will produce the date portion
    * of the string.
    * @param dataType
    * @return
    */
   private Pattern fetchDateLocationPattern(String dataType) {
     if (datePatternMap.containsKey(dataType)) {
       return datePatternMap.get(dataType);
     }
 
     JobConf jobConf = Demux.jobConf;
     String datePattern = null;
 
     if (jobConf != null) {
       datePattern = jobConf.get("TsProcessor.default.time.regex", null);
       datePattern = jobConf.get("TsProcessor.time.regex." + chunk.getDataType(),
                                datePattern);
     }
 
     Pattern pattern = datePattern != null ? Pattern.compile(datePattern) : null;
     datePatternMap.put(dataType, pattern);
 
     return pattern;
   }
 
 }