/**
 * 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
 * <p/>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p/>
 * 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.mapred.gridmix;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.mapred.ClusterStatus;
import org.apache.hadoop.mapred.JobClient;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.gridmix.GenerateData.GenSplit;
import org.apache.hadoop.mapreduce.InputSplit;
import org.apache.hadoop.security.UserGroupInformation;
import org.apache.hadoop.tools.rumen.JobStory;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Random;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public enum JobCreator {

  LOADJOB {
    @Override
    public GridmixJob createGridmixJob(
      Configuration conf, long submissionMillis, JobStory jobdesc, Path outRoot,
      UserGroupInformation ugi, int seq) throws IOException {
      return new LoadJob(conf, submissionMillis, jobdesc, outRoot, ugi, seq);
    }},

  SLEEPJOB {
    private String[] hosts;
      
    @Override
    public GridmixJob createGridmixJob(
      Configuration conf, long submissionMillis, JobStory jobdesc, Path outRoot,
      UserGroupInformation ugi, int seq) throws IOException {
      int numLocations = conf.getInt(SLEEPJOB_RANDOM_LOCATIONS, 0);
      if (numLocations < 0) numLocations=0;
      if ((numLocations > 0) && (hosts == null)) {
        final JobClient client = new JobClient(new JobConf(conf));
        ClusterStatus stat = client.getClusterStatus(true);
        final int nTrackers = stat.getTaskTrackers();
        final ArrayList<String> hostList = new ArrayList<String>(nTrackers);
        final Pattern trackerPattern = Pattern.compile("tracker_([^:]*):.*");
        final Matcher m = trackerPattern.matcher("");
        for (String tracker : stat.getActiveTrackerNames()) {
          m.reset(tracker);
          if (!m.find()) {
            continue;
          }
          final String name = m.group(1);
          hostList.add(name);
        }
        hosts = hostList.toArray(new String[hostList.size()]);
      }
      return new SleepJob(conf, submissionMillis, jobdesc, outRoot, ugi, seq,
          numLocations, hosts);
    }};

  public static final String GRIDMIX_JOB_TYPE = "gridmix.job.type";
  public static final String SLEEPJOB_RANDOM_LOCATIONS = 
    "gridmix.sleep.fake-locations";

  public abstract GridmixJob createGridmixJob(
    final Configuration conf, long submissionMillis, final JobStory jobdesc,
    Path outRoot, UserGroupInformation ugi, final int seq) throws IOException;

  public static JobCreator getPolicy(
    Configuration conf, JobCreator defaultPolicy) {
    return conf.getEnum(GRIDMIX_JOB_TYPE, defaultPolicy);
  }
}