package AvilaGPSSerial;

import java.util.Vector;
import java.io.IOException;
import java.io.OutputStream;
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
import javax.microedition.location.Coordinates;
import javax.microedition.location.LocationListener;
import javax.microedition.location.LocationProvider;
import javax.microedition.location.Criteria;
import javax.microedition.location.Location;
import javax.microedition.io.CommConnection;
import javax.microedition.io.Connector;
import javax.microedition.location.LocationException;
import javax.microedition.location.QualifiedCoordinates;

public class AvilaGPSSerial extends MIDlet implements CommandListener,LocationListener,Runnable {

    private final Command exitCmd = new Command("Exit", Command.EXIT, 1);
    private Command startPort = new Command("Start port", Command.SCREEN,1);
    private Command stopPort = new Command("Stop port", Command.SCREEN,1);
    private Command sendTestMessage = new Command("Send Test", Command.SCREEN,1);
    private Display display;
    private Form mainForm;
    private ChoiceGroup portChoice;
    private String currentPort;
    private byte[] msg;
    private LocationProvider provider;
    private Criteria criteria;
    private StringItem latitude;
    private StringItem longitude;
    private Thread gpsThread;
    private boolean sending = false;


    public AvilaGPSSerial() {

    }

    protected void destroyApp(boolean unconditional) {

    }

    protected void pauseApp() {
    }

    protected void startApp() throws MIDletStateChangeException {
        display = Display.getDisplay(this);
        mainForm = new Form("AvilaGPSSerial");
        mainForm.addCommand(exitCmd);
        mainForm.addCommand(startPort);
        mainForm.addCommand(sendTestMessage);
        mainForm.setCommandListener(this);

        latitude=new StringItem("Latitude:","N/A");
        longitude=new StringItem("Longitude:","N/A");

        mainForm.append(latitude);
        mainForm.append(longitude);

        fillPortChoice();

        msg = new byte[3];
        msg[1] = 123;
        display.setCurrent(mainForm);
        gpsThread = new Thread(this);
        gpsThread.start();
    }

    public void run() {
        try{
            criteria=new Criteria();
            criteria.setPreferredPowerConsumption(Criteria.POWER_USAGE_HIGH);
            provider = LocationProvider.getInstance(criteria);
            provider.setLocationListener(this, -1, -1, -1);
        }catch(Exception e) {
             Alert alert = new Alert("Error", "Could not retrieve location!", null, AlertType.ERROR);
             display.setCurrent(alert);
        }
    }

    public void locationUpdated(LocationProvider arg0, Location loc) {
        if(loc.isValid()) {
            QualifiedCoordinates c=loc.getQualifiedCoordinates();
            latitude.setText(String.valueOf(c.getLatitude()));
            longitude.setText(String.valueOf(c.getLongitude()));
            byte[] message = convertFloatCoordsToByteArray(c.getLatitude(),c.getLongitude());
            if(sending){
                try{
                    writeBytesToSerialPort(msg,currentPort);
                } catch(IOException e){
                    Alert alert = new Alert("Error", "Could not send location to serial port!", null, AlertType.ERROR);
                    display.setCurrent(alert);
                }
            }
        }
    }


    public void providerStateChanged(LocationProvider provider, int newState) {
    }

    public void commandAction(Command c, Displayable d) {
        if (c == exitCmd) {
            destroyApp(false);
            notifyDestroyed();
        }
        else if(c == startPort){
            sending = true;
            int index = portChoice.getSelectedIndex();
            currentPort = portChoice.getString(index);
            mainForm.removeCommand(startPort);
            mainForm.addCommand(stopPort);
        }
        else if(c == stopPort){
            sending = false;
            int index = portChoice.getSelectedIndex();
            currentPort = portChoice.getString(index);
            mainForm.removeCommand(stopPort);
            mainForm.addCommand(startPort);
        }
        else if(c == sendTestMessage){
            byte[] msg = new byte[4];
            msg[1] = 1;
            msg[2] = 2;
            msg[3] = 120;
            try{
                writeBytesToSerialPort(msg,currentPort);
            } catch(IOException e){
                Alert alert = new Alert("Error", "Could not send location to serial port!", null, AlertType.ERROR);
                display.setCurrent(alert);
            }
        }
    }

    private String[] findPorts() {
        String portsString = System.getProperty("microedition.commports");

        Vector nodes = new Vector();
        String separator = ",";
            // Parse nodes into vector

        int index = portsString.indexOf(separator);
        while(index >= 0) {
            nodes.addElement( portsString.substring(0, index) );
            portsString = portsString.substring(index+separator.length());
            index = portsString.indexOf(separator);
        }
            // Get the last node
        nodes.addElement( portsString );

             // Create split string array
        String[] ports = new String[ nodes.size() ];
        if( nodes.size() > 0 ) {
            for(int i = 0; i < nodes.size(); i++){
                ports[i] = (String)nodes.elementAt(i);
            }
        }
        return ports;
    }

    private void writeBytesToSerialPort(byte[] message, String port) throws IOException {
        CommConnection device = (CommConnection) Connector.open(port);
        OutputStream os = device.openOutputStream();
        os.write(message);
        os.close();
        device.close();
    }

    private void fillPortChoice(){
        String[] ports = findPorts();
        portChoice = new ChoiceGroup("Port: ",ChoiceGroup.EXCLUSIVE,ports,null);
        mainForm.append(portChoice);
    }

    private byte[] convertFloatCoordsToByteArray(double latitude, double longitude){

        byte[] latArray = new byte[8];
        long lng = Double.doubleToLongBits(latitude);
        for(int i = 0; i < 8; i++){
             latArray[i] = (byte)((lng >> ((7 - i) * 8)) & 0xff);
        }

        byte[] lonArray = new byte[8];
        lng = Double.doubleToLongBits(latitude);
        for(int i = 0; i < 8; i++){
             lonArray[i] = (byte)((lng >> ((7 - i) * 8)) & 0xff);
        }

        byte[] result = new byte[17];
        for(int i = 1; i < latArray.length;++i)
        {
            result[i]= latArray[i];
            result[i+4]= lonArray[i];
        }
        return result;
    }
}