import java.io.*;
import javax.bluetooth.*;
import javax.microedition.io.*;

public class BluetoothTracker {

  public static void main(String[] args) throws IOException {
    
    RemoteDevice logger = BlueLoggerFinder.findBlueLogger();
    String address = logger.getBluetoothAddress();
    String url = "btspp://" + address 
     + ":1;authenticate=false;encrypt=false;master=false";
    StreamConnection conn = (StreamConnection) Connector.open(url);
    InputStream in  = conn.openInputStream();
    BufferedReader reader = new BufferedReader(
                             new InputStreamReader(in, "US-ASCII"));
    try {
      while (true) {
        String s = reader.readLine();
        if (s == null) break; 
        if (s.startsWith("$GPRMC,")) {
          String[] fields = s.split(",");
          String time = getTime(fields[1]);
          String latitude = getPosition(fields[3], fields[4]);
          String longitude = getPosition(fields[5], fields[6]);
          String date = getDate(fields[9]);
          System.out.println(time + "\t" + date + "\t" 
                           + latitude + "\t" + longitude);
        }
      }
    }
    catch (IOException ex) {
      // device turned off or out of range 
    }
    reader.close();
    
  }

  private static String getDate(String ddmmyy) {
    String year = "20" + ddmmyy.substring(4);
    String month = ddmmyy.substring(2, 4);
    String day = ddmmyy.substring(0, 2);    
    return month + "-" + day + "-" + year;
  }

  // I'm not sure how robust this code is. There could well be some
  // StringIndexOutOfBoundsExceptions waiting to trip up the unwary.
  // I have not tested it at every possible location on the planet. 
  private static String getPosition(String number, String direction) {
    // need to handle two digit and three digit longitude
    int point = number.indexOf('.');
    String degrees = number.substring(0, point-2);
    String minutes = number.substring(degrees.length(), point);
    String seconds = String.valueOf(
     Double.parseDouble(number.substring(point)) * 60);
    
    return degrees + "°" + minutes + "'" + seconds + "\"" + direction;
  }

  private static String getTime(String in) {
    String hours = in.substring(0, 2);
    String minutes = in.substring(2, 4);
    String seconds = in.substring(4, 6);
    return hours + ":" + minutes + ":" + seconds;
  }
}