class OptionsParser {

  public static DistCpOptions parse(String args[]) throws IllegalArgumentException {

    CommandLineParser parser = new CustomParser();

    CommandLine command;
    try {
      command = parser.parse(cliOptions, args, true);
    } catch (ParseException e) {
      throw new IllegalArgumentException("Unable to parse arguments. " +
        Arrays.toString(args), e);
    }

    DistCpOptions option;
    Path targetPath;
    List<Path> sourcePaths = new ArrayList<Path>();

    String leftOverArgs[] = command.getArgs();
    if (leftOverArgs == null || leftOverArgs.length < 1) {
      throw new IllegalArgumentException("Target path not specified");
    }

    //Last Argument is the target path
    targetPath = new Path(leftOverArgs[leftOverArgs.length -1].trim());

    //Copy any source paths in the arguments to the list
    for (int index = 0; index < leftOverArgs.length - 1; index++) {
      sourcePaths.add(new Path(leftOverArgs[index].trim()));
    }

    /* If command has source file listing, use it else, fall back on source paths in args
       If both are present, throw exception and bail */
    if (command.hasOption(DistCpOptionSwitch.SOURCE_FILE_LISTING.getSwitch())) {
      if (!sourcePaths.isEmpty()) {
        throw new IllegalArgumentException("Both source file listing and source paths present");
      }
      option = new DistCpOptions(new Path(getVal(command, DistCpOptionSwitch.
              SOURCE_FILE_LISTING.getSwitch())), targetPath);
    } else {
      if (sourcePaths.isEmpty()) {
        throw new IllegalArgumentException("Neither source file listing nor source paths present");
      }
      option = new DistCpOptions(sourcePaths, targetPath);
    }

    //Process all the other option switches and set options appropriately
    if (command.hasOption(DistCpOptionSwitch.IGNORE_FAILURES.getSwitch())) {
      option.setIgnoreFailures(true);
    }

    if (command.hasOption(DistCpOptionSwitch.PRESERVE_SRC_PATH.getSwitch())) {
      option.setPreserveSrcPath(true);
    }

    if (command.hasOption(DistCpOptionSwitch.ATOMIC_COMMIT.getSwitch())) {
      option.setAtomicCommit(true);
    }

    if (command.hasOption(DistCpOptionSwitch.WORK_PATH.getSwitch()) &&
        option.shouldAtomicCommit()) {
      String workPath = getVal(command, DistCpOptionSwitch.WORK_PATH.getSwitch());
      if (workPath != null && !workPath.isEmpty()) {
        option.setAtomicWorkPath(new Path(workPath));
      }
    } else if (command.hasOption(DistCpOptionSwitch.WORK_PATH.getSwitch())) {
      throw new IllegalArgumentException("-tmp work-path can only be specified along with -atomic");      
    }

    if (command.hasOption(DistCpOptionSwitch.LOG_PATH.getSwitch())) {
      option.setLogPath(new Path(getVal(command, DistCpOptionSwitch.LOG_PATH.getSwitch())));
    }

    if (command.hasOption(DistCpOptionSwitch.SYNC_FOLDERS.getSwitch())) {
      option.setSyncFolder(true);
    }

    if (command.hasOption(DistCpOptionSwitch.OVERWRITE.getSwitch())) {
      option.setOverwrite(true);
    }

    if (command.hasOption(DistCpOptionSwitch.DELETE_MISSING.getSwitch())) {
      option.setDeleteMissing(true);
    }

    if (command.hasOption(DistCpOptionSwitch.SKIP_CRC.getSwitch())) {
      option.setSkipCRC(true);
    }

    if (command.hasOption(DistCpOptionSwitch.BLOCKING.getSwitch())) {
      option.setBlocking(false);
    }

    if (command.hasOption(DistCpOptionSwitch.BANDWIDTH.getSwitch())) {
      try {
        Integer mapBandwidth = Integer.parseInt(
            getVal(command, DistCpOptionSwitch.BANDWIDTH.getSwitch()).trim());
        option.setMapBandwidth(mapBandwidth);
      } catch (NumberFormatException e) {
        throw new IllegalArgumentException("Bandwidth specified is invalid: " +
            getVal(command, DistCpOptionSwitch.BANDWIDTH.getSwitch()), e);
      }
    }

    if (command.hasOption(DistCpOptionSwitch.BANDWIDTH_KB.getSwitch())) {
      try {
        Integer mapBandwidth = Integer.parseInt(
            getVal(command, DistCpOptionSwitch.BANDWIDTH_KB.getSwitch()).trim());
        option.setMapBandwidthKB(mapBandwidth);
      } catch (NumberFormatException e) {
        throw new IllegalArgumentException("Bandwidth specified is invalid: " +
            getVal(command, DistCpOptionSwitch.BANDWIDTH_KB.getSwitch()), e);
      }
    }

    if (command.hasOption(DistCpOptionSwitch.SSL_CONF.getSwitch())) {
      option.setSslConfigurationFile(command.
          getOptionValue(DistCpOptionSwitch.SSL_CONF.getSwitch()));
    }

    if (command.hasOption(DistCpOptionSwitch.MAX_MAPS.getSwitch())) {
      try {
        Integer maps = Integer.parseInt(
            getVal(command, DistCpOptionSwitch.MAX_MAPS.getSwitch()).trim());
        option.setMaxMaps(maps);
      } catch (NumberFormatException e) {
        throw new IllegalArgumentException("Number of maps is invalid: " +
            getVal(command, DistCpOptionSwitch.MAX_MAPS.getSwitch()), e);
      }
    }

    if (command.hasOption(DistCpOptionSwitch.COPY_STRATEGY.getSwitch())) {
      option.setCopyStrategy(
            getVal(command, DistCpOptionSwitch.COPY_STRATEGY.getSwitch()));
    }

    if (command.hasOption(DistCpOptionSwitch.PRESERVE_STATUS.getSwitch())) {
      String attributes =
          getVal(command, DistCpOptionSwitch.PRESERVE_STATUS.getSwitch());
      if (attributes == null || attributes.isEmpty()) {
        for (FileAttribute attribute : FileAttribute.values()) {
          option.preserve(attribute);
        }
      } else {
        for (int index = 0; index < attributes.length(); index++) {
          option.preserve(FileAttribute.
              getAttribute(attributes.charAt(index)));
        }
      }
    }

    if (command.hasOption(DistCpOptionSwitch.FILE_LIMIT.getSwitch())) {
      String fileLimitString = getVal(command,
                              DistCpOptionSwitch.FILE_LIMIT.getSwitch().trim());
      try {
        Integer.parseInt(fileLimitString);
      }
      catch (NumberFormatException e) {
        throw new IllegalArgumentException("File-limit is invalid: "
                                            + fileLimitString, e);
      }
      LOG.warn(DistCpOptionSwitch.FILE_LIMIT.getSwitch() + " is a deprecated" +
              " option. Ignoring.");
    }

    if (command.hasOption(DistCpOptionSwitch.SIZE_LIMIT.getSwitch())) {
      String sizeLimitString = getVal(command,
                              DistCpOptionSwitch.SIZE_LIMIT.getSwitch().trim());
      try {
        Long.parseLong(sizeLimitString);
      }
      catch (NumberFormatException e) {
        throw new IllegalArgumentException("Size-limit is invalid: "
                                            + sizeLimitString, e);
      }
      LOG.warn(DistCpOptionSwitch.SIZE_LIMIT.getSwitch() + " is a deprecated" +
              " option. Ignoring.");
    }

    return option;
  }

}