import java.io.*;
import java.util.ArrayList;
import java.io.IOException;
import java.util.StringTokenizer;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;

import org.apache.hadoop.mapreduce.lib.input.FileSplit;
import org.apache.log4j.Logger;

public class ExecutionTimeTracker {

  public static class TokenizerMapper
       extends Mapper<Object, Text, Text, IntWritable>{

    private final static IntWritable one = new IntWritable(1);
    private Text word = new Text();
    private final Logger LOG = org.apache.log4j.Logger.getLogger(this.getClass());

    public void map(Object key, Text value, Context context
                    ) throws IOException, InterruptedException {
      StringTokenizer itr = new StringTokenizer(value.toString());

      FileSplit fileSplit = (FileSplit)context.getInputSplit();
      String filename = fileSplit.getPath().getName();

      //to write the file name as key
      Text text = new Text();
      text.set(filename);
      LOG.warn("fileName: " + filename);

      try {
          // command execution
          Runtime rt = Runtime.getRuntime();
          String evmDir = "evm";
          String command = evmDir + " --debug --code " + value.toString() + " run";
          Process proc = Runtime.getRuntime().exec(command);
          BufferedReader stdInput = new BufferedReader(new InputStreamReader(proc.getInputStream()));

          // output data struct
          ArrayList<String> consoleOutput = new ArrayList<String>();
          String s = null;
          while ((s = stdInput.readLine()) != null) {
              consoleOutput.add(s);
          }
          for (String p : consoleOutput) {
              Pattern pattern = Pattern.compile("([A-Za-z]+)([ \t]+)(\\d+)");
              Matcher matcher = pattern.matcher(p);
              while (matcher.find()) {
                  String groupThree = matcher.group(3);
                  IntWritable writeValue = new IntWritable(Integer.parseInt(groupThree));
                  context.write(text, writeValue);
              }
          }
      } catch (IOException e) {
          LOG.warn("Exception Encountered!");
          LOG.warn(e);
      }
    }
  }

  public static class IntSumReducer
       extends Reducer<Text,IntWritable,Text,IntWritable> {
    private IntWritable result = new IntWritable();

    public void reduce(Text 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);
    }
  }

  public static void main(String[] args) throws Exception {
    Configuration conf = new Configuration();
    Job job = Job.getInstance(conf, "execution time tracker");
    job.setJarByClass(ExecutionTimeTracker.class);
    job.setMapperClass(TokenizerMapper.class);
    job.setCombinerClass(IntSumReducer.class);
    job.setReducerClass(IntSumReducer.class);
    job.setOutputKeyClass(Text.class);
    job.setOutputValueClass(IntWritable.class);
    FileInputFormat.addInputPath(job, new Path(args[0]));
    FileOutputFormat.setOutputPath(job, new Path(args[1] + "/" + System.currentTimeMillis()));
    System.exit(job.waitForCompletion(true) ? 0 : 1);
  }
}