package voip;

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

public class RTPManager extends UdpManager
{
    SIPMsg sipMsg = null;

    boolean doCipher = false;

    boolean stop = false;


    RTPManager(SIPMsg sipMsg)
    {
        super();

        this.sipMsg = sipMsg;

        System.out.println("RTP Manager: " + myAddr.toString() + ":" + myPort);
    }


    public void run()
    {
        System.out.println("doCipher = " + doCipher);

        try
        {
            while ( !stop )
            {
                DatagramPacket packet = new DatagramPacket(
                    new byte[Constants.MAX_RTP_PACKET_SIZE],
                    Constants.MAX_RTP_PACKET_SIZE
                    );

                //    Waits for a datagram packet to arrive.
                socket.receive( packet );

                //    Change the address and port number appropriately:
                DatagramPacket newPacket = rewritePacket( packet );

                //    Send the modified packet to the guest.
                if (newPacket != null)
                    socket.send( newPacket );
            }
            socket.close();
        }
        catch ( IOException e )
        {
            System.out.println("Unable to communicate with media proxy or just getting terminated" + e.getMessage());
            e.printStackTrace();
            socket.close();
        }
    }

    void setDoCipher(boolean doCipher)
    {
        this.doCipher = doCipher;
        return;
    }

    void terminate()
    {
        System.out.println("terminating RTP manager...");
        stop = true;
    }

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

        if ( packet.getAddress().equals(clientAddr) )   // from my client!
        {
            //  Change the port number in the packet to be mine.
            String newDP = replaceAddress(packet, guestAddr, guestPort);

            //  Encrypt the data if required.
            if (doCipher)
            {
                byte[] data = SIPMsg.encryptMedia(newDP.getBytes());
                if ( data != null )
                {
                    newPacket.setData(data);
                }
                else
                    return null;
            }
            else
            {
                newPacket.setData(newDP.getBytes());
            }

            newPacket.setAddress(guestAddr);
            newPacket.setPort(guestPort);
        }

        return newPacket;
    }

    private String replaceAddress (DatagramPacket packet, InetAddress addr, int port)
    {
        StringBuffer    buffer = new StringBuffer(new String(packet.getData(),0,packet.getLength()));
        String          strMyPort = new String(myPort + "(" + myPort + ")");
        String          strPort = new String(port + "(" + port + ")");

        int i   = 0;
        int max = buffer.length();
        int nPort = strMyPort.length();

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

        String  strMyAddr = new String(myAddr.toString() + "(" + myAddr.toString() + ")");
        String  strAddr = new String(addr.toString() + "(" + addr.toString() + ")");

        i   = 0;
        max = buffer.length();
        int nAddr = strMyAddr.length();

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

        return buffer.toString();
    }

    public InetAddress extractMediaAddr(String packetStr)
    {
        int first = packetStr.indexOf("c=");
        int end = packetStr.indexOf("\r\n", first);
        StringTokenizer st = new StringTokenizer(packetStr.substring(first, end).trim(), " ");

        st.nextToken(); //  Get rid of "c=IN"
        st.nextToken(); //  Get rid of "IP4"
        String ipStr = st.nextToken();// String of octet dotted IP address

        InetAddress addr = null;
        try
        {
            addr = InetAddress.getByName(ipStr);
        }
        catch (UnknownHostException e)
        {
            logger.error("Unable to create InetAddress: " + e.getMessage());
            e.printStackTrace();
        }

        return addr;
    }

    public int extractMediaPort(String packetStr)
    {
        String headStr = "m=audio ";
        int index = packetStr.indexOf(headStr);
        index += headStr.length();
        String portStr = packetStr.substring(index, index+5).trim();

        return Integer.parseInt(portStr);
    }

    public String replaceMediaInfo(String packetStr, String toAddr, String addr, int toPort, int port)
    {
        StringBuffer    buffer = new StringBuffer(packetStr);


        if (port != 0 && toPort != 0)
        {
            String headStr = "m=audio ";
            int index = buffer.indexOf(headStr);
            index += headStr.length();
            int portLength = String.valueOf(port).length();
            buffer.replace(index, index + portLength, String.valueOf(toPort));
        }

        if (addr != null && toAddr != null)
        {
            int index = addr.indexOf("/");
            if (index != -1)
                addr = addr.substring(index + 1);   // Get rid of hostname + "/"

            index = toAddr.indexOf("/");
            if (index != -1)
                toAddr = toAddr.substring(index + 1);    // Get rid of hostname + "/"

            int i   = 0;
            int max = buffer.length();
            int nAddr = addr.length();

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

        return buffer.toString();
    }

    public String updateContentLength(String packetStr, int nKeySize)
    {
    	StringBuffer    buffer = new StringBuffer(packetStr);
    	int beginning = buffer.indexOf(Constants.CONTENT_LENGTH);
    	beginning += Constants.CONTENT_LENGTH.length();
    	int end = beginning + 3; 	// HACTICING: The value should be no more than three digit

    	String strNum = buffer.substring(beginning, end).trim();

    	int lenMsg = Integer.parseInt(strNum);
    	lenMsg += nKeySize;

    	buffer.replace(beginning, end, String.valueOf(lenMsg));

    	return buffer.toString();
    }

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