package voip;

import java.net.DatagramPacket;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.StringTokenizer;

public class SIPManager extends UDPManager
{
/
    SIPMsg sipMsg = null;

    SIPManager(int port, SIPMsg sipMsg)
    {
        super(port);

        this.sipMsg = sipMsg;
        System.out.println("SIPManager: " + myAddr.toString() + ":" + myPort);
    }

    protected DatagramPacket rewritePacket (DatagramPacket packet)
    {
        DatagramPacket newPacket = new DatagramPacket(new byte[Constants.MAX_PACKET_SIZE], Constants.MAX_PACKET_SIZE);
        String packetStr = new String(packet.getData(),0,packet.getLength());
        String strFrom = null;

        long 	tStart = System.currentTimeMillis();

        try
        {
            //  This packet is from my client!
            strFrom = "client";

            //  Fill in the data at the first-time
            if (clientAddr == null)
            {
                clientAddr = packet.getAddress();
                clientPort = packet.getPort();
            }

            //  Change the port number in the packet to be mine.
            packetStr = replacePortNumber(packet, clientPort, myPort);
            newPacket.setData(packetStr.getBytes());

            //  Set the new destination
            newPacket.setAddress(clientAddr);
            newPacket.setPort(clientPort);

            //  Update to the current SIP method in the given packet
            packetStr = new String(newPacket.getData(),0,newPacket.getLength());
            packetStr = sipMsg.executeSIPMethod(packetStr, strFrom);
            newPacket.setData(packetStr.getBytes());

            long 	tEnd = System.currentTimeMillis();
            System.out.println("\nrewritten packet: " + System.currentTimeMillis() + " time diff: " + (tEnd - tStart) + "\n" + new String(newPacket.getData(),0,newPacket.getLength()));
        }
        catch(UnknownHostException e)
        {
            System.out.println("Unable to create host: " + e.getMessage());
            e.printStackTrace();
        }

        return newPacket;
    }

    protected String replacePortNumber(DatagramPacket packet, int fromPort, int toPort)
    {
        StringBuffer    buffer = new StringBuffer(new String(packet.getData(),0,packet.getLength()));
        String          strFromPort = ":" + fromPort;
        String          strToPort = ":" + toPort;

        int i = 0;
        int max = buffer.length();
        int nFromPort = strFromPort.length();

        while (i < max)
        {
            if ((i = buffer.indexOf(strFromPort, i)) == -1)
            {
                // No more matches
                break;
            }
            else
            {
                // Replace the port number as proxy's
                buffer.replace(i, i + nFromPort, strToPort);
            }
            i += nFromPort;
        }

        strFromPort = "=" + fromPort;
        strToPort = "=" + toPort;

        i   = 0;
        max = buffer.length();
        nFromPort = strFromPort.length();

        while (i < max)
        {
            if ((i = buffer.indexOf(strFromPort, i)) == -1)
            {
                // No more matches
                break;
            }
            else
            {
                // Replace the port number as proxy's
                buffer.replace(i, i + nFromPort, strToPort);
            }
            i += nFromPort;
        }

        return buffer.toString();
    }

    public String toString()
    {
        return  "SIPManager:\n" + super.toString();
    }
}