package voip;

import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;

import java.net.SocketException;
import java.net.UnknownHostException;
import java.io.IOException;

public abstract class UdpManager implements Runnable
{
    protected DatagramSocket socket    = null;

    protected InetAddress clientAddr   = null;
    protected int         clientPort   = 0;

    protected InetAddress myAddr   = null;
    protected int         myPort   = 0;

    public UDPManager()
    {
        try
        {
            socket = new DatagramSocket();

            myAddr = InetAddress.getLocalHost();
            myPort = socket.getLocalPort();
        }
        catch (SocketException e)
        {
            System.out.println("Unable to start UDPManager: " + e.getMessage());
            e.printStackTrace();
        }
        catch(UnknownHostException ex)
        {
            System.out.println("Unable to create InetAddress out of localhost: " + ex.getMessage());
            ex.printStackTrace();
        }
    }

    public UDPManager(int port)
    {
        try
        {
            socket = new DatagramSocket(port);

            myAddr = InetAddress.getLocalHost();
            myPort = port;
        }
        catch (SocketException e)
        {
            System.out.println("Unable to start UDPManager: " + e.getMessage());
            e.printStackTrace();
        }
        catch(UnknownHostException ex)
        {
            System.out.println("Unable to create InetAddress out of localhost: " + ex.getMessage());
            ex.printStackTrace();
        }
    }

    public void run()
    {
        try
        {
            while ( true )
            {
                DatagramPacket packet = new DatagramPacket(new byte[Constants.MAX_PACKET_SIZE], Constants.MAX_PACKET_SIZE);

                socket.receive( packet );

                DatagramPacket newPacket = rewritePacket( packet );

                if (newPacket != null)
                    socket.send( newPacket );
            }
        }
        catch ( IOException e )
        {
            System.out.println("Unable to communicate with UDP client: " + e.getMessage());
            e.printStackTrace();
        }
    }

    abstract protected DatagramPacket rewritePacket (DatagramPacket packet);

    InetAddress getMyAddr()
    {
        return myAddr;
    }

    void setMyAddr(InetAddress addr)
    {
        myAddr = addr;
    }

    int getMyPort()
    {
        return myPort;
    }

    void setMyPort(int port)
    {
        myPort = port;
    }

    InetAddress getClientAddr()
    {
        return clientAddr;
    }

    void setClientAddr(InetAddress addr)
    {
        clientAddr = addr;
    }

    int getClientPort()
    {
        return clientPort;
    }

    void setClientPort(int port)
    {
        clientPort = port;
    }

    public String toString()
    {
        Assert.assertTrue(myAddr!=null);
        Assert.assertTrue(clientAddr!=null);
        Assert.assertTrue(guestAddr!=null);

        return  "my addr = " + myAddr.toString() + ":" + myPort + "\n" +
                "client: " + clientAddr.toString() + ":" + clientPort + "\n";
    }
}