static class ProgramScan {
  static int threads = isWindows() ? 500 : 10;
  static int timeout = 5000; // hmm...
  static String ip = "127.0.0.1";
  
  // This range is not used anymore anyway
  static int quickScanFrom = 10000, quickScanTo = 10999;

  static int maxNumberOfVMs_android = 4; // Android will always only have one if we don't screw up
  static int maxNumberOfVMs_nonAndroid = 50; // 100;
  static int maxNumberOfVMs;
  
  static boolean verbose;
  
  static class Program {
    int port;
    String helloString;
    
    *(int *port, String *helloString) {}
  }
  
  static List<Program> scan() ctex {
    return scan(1, 65535);
  }
  
  static List<Program> scan(int fromPort, int toPort) {
    return scan(fromPort, toPort, new int[0]);
  }
  
  static List<Program> scan(int fromPort, int toPort, int[] preferredPorts) ctex {
    Set<int> preferredPortsSet = new HashSet<int>(asList(preferredPorts));
    int scanSize = toPort-fromPort+1;
    S name = toPort < 10000 ? "bot" : "program";
    int threads = isWindows() ? min(500, scanSize) : min(scanSize, 10);
    final ExecutorService es = Executors.newFixedThreadPool(threads);
    if (verbose) print(firstToUpper(name) + "-scanning " + ip + " with timeout " + timeout + " ms in " + threads + " threads.");
    startTiming();
    new List<Future<Program>> futures;
    new L<Int> ports;
    for (int port : preferredPorts) {
      futures.add(checkPort(es, ip, port, timeout));
      ports.add(port);
    }
    for (int port = fromPort; port <= toPort; port++)
      if (!preferredPortsSet.contains(port) && !forbiddenPort(port)) {
        futures.add(checkPort(es, ip, port, timeout));
        ports.add(port);
      }
    es.shutdown();
    new List<Program> programs;
    long time = now();
    int i = 0;
    for (final Future<Program> f : futures) {
      if (verbose) print("Waiting for port " + get(ports, i++) + " at time " + (now()-time));
      Program p = f.get();
      if (p != null)
        programs.add(p);
    }
    //stopTiming("Port Scan " + scanSize + ", " + n(threads, "threads") + ": ", 250);
    if (verbose) print("Found " + programs.size() + " " + name + "(s) on " + ip);
    return programs;
  }

  static Future<Program> checkPort(final ExecutorService es, final String ip, final int port, final int timeout) {
    return es.submit(new Callable<Program>() {
        @Override public Program call() {
          try {
            Socket socket = new Socket();
            try {
              socket.setSoTimeout(timeout);
              socket.connect(new InetSocketAddress(ip, port), timeout);
              //if (verbose) print("Connected to " + ip + ":" + port);
              BufferedReader in = new BufferedReader(
                new InputStreamReader(socket.getInputStream(), "UTF-8"));
              S hello = or(in.readLine(), "?");
              return new Program(port, hello);
            } finally {
              socket.close();
            }
          } catch (Exception ex) {
            return null;
          }
        }
     });
  }
  
  static List<Program> quickScan() {
    return scan(quickScanFrom, quickScanTo);
  }
  
  static List<Program> quickBotScan() {
    return quickBotScan(new int[0]);
  }
  
  static List<Program> quickBotScan(int[] preferredPorts) {
    if (maxNumberOfVMs == 0)
      maxNumberOfVMs = isAndroid() ? maxNumberOfVMs_android : maxNumberOfVMs_nonAndroid;
    return scan(4999, 5000+maxNumberOfVMs-1, preferredPorts);
  }
}