package net.sourceforge.jsocks;
import java.io.DataInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.UnknownHostException;

/**
  SOCKS4 Reply/Request message.
*/

public class Socks4Message extends ProxyMessage {

    private byte[] msgBytes;
    private int msgLength;

    /**
     * Server failed reply, cmd command for failed request
     */
    public Socks4Message(int cmd) {
        super(cmd, null, 0);
        this.user    = null;
        msgLength = 2;
        msgBytes = new byte[2];
        msgBytes[0] = (byte) 0;
        msgBytes[1] = (byte) command;
    }

    /**
     *  Server successfull reply
     */
    public Socks4Message(int cmd, InetAddress ip, int port) {
        this(0, cmd, ip, port, null);
    }

    /**
     *  Client request
     */
    public Socks4Message(int cmd, InetAddress ip, int port, String user) {
        this(SOCKS_VERSION, cmd, ip, port, user);
    }

    /**
     * Most general constructor
     */
    public Socks4Message(int version, int cmd,
                         InetAddress ip, int port, String user) {
        super(cmd, ip, port);
        this.user    = user;
        this.version = version;
        msgLength = user == null ? 8 : 9 + user.length();
        msgBytes = new byte[msgLength];
        msgBytes[0] = (byte) version;
        msgBytes[1] = (byte) command;
        msgBytes[2] = (byte)(port >> 8);
        msgBytes[3] = (byte) port;
        byte[] addr;

        if (ip != null)
            addr = ip.getAddress();
        else {
            addr = new byte[4];
            addr[0] = addr[1] = addr[2] = addr[3] = 0;
        }

        System.arraycopy(addr, 0, msgBytes, 4, 4);

        if (user != null) {
            byte[] buf = user.getBytes();
            System.arraycopy(buf, 0, msgBytes, 8, buf.length);
            msgBytes[msgBytes.length - 1 ] = 0;
        }
    }

    /**
     *Initialise from the stream
     *If clientMode is true attempts to read a server response
     *otherwise reads a client request
     *see read for more detail
     */
    public Socks4Message(InputStream in, boolean clientMode) throws IOException {
        msgBytes = null;
        read(in, clientMode);
    }

    @Override
    public void read(InputStream in) throws IOException {
        read(in, true);
    }

    @Override
    public void read(InputStream in, boolean clientMode) throws IOException {
        boolean mode4a = false;
        DataInputStream d_in = new DataInputStream(in);
        version = d_in.readUnsignedByte();
        command = d_in.readUnsignedByte();

        if (clientMode && command != REPLY_OK) {
            String errMsg;

            if (command > REPLY_OK && command < REPLY_BAD_IDENTD)
                errMsg = replyMessage[command - REPLY_OK];
            else
                errMsg = "Unknown Reply Code";

            throw new SocksException(command, errMsg);
        }

        port = d_in.readUnsignedShort();
        byte[] addr = new byte[4];
        d_in.readFully(addr);

        if (addr[0] == 0 && addr[1] == 0 && addr[2] == 0 && addr[3] != 0)
            mode4a = true;
        else {
            ip = bytes2IP(addr);
            host = ip.getHostName();
        }

        if (!clientMode) {
            StringBuilder sb = new StringBuilder();
            int b;

            while ((b = in.read()) != 0)
                sb.append((char) b);

            user = sb.toString();

            if (mode4a) {
                sb.setLength(0);

                while ((b = in.read()) != 0)
                    sb.append((char) b);

                host = sb.toString();
            }
        }
    }
    @Override
    public void write(OutputStream out) throws IOException {
        if (msgBytes == null) {
            Socks4Message msg = new Socks4Message(version, command, ip, port, user);
            msgBytes = msg.msgBytes;
            msgLength = msg.msgLength;
        }

        out.write(msgBytes);
    }

    //Class methods
    static InetAddress bytes2IP(byte[] addr) {
        String s = bytes2IPV4(addr, 0);

        try {
            return InetAddress.getByName(s);
        }
        catch (UnknownHostException uh_ex) {
            return null;
        }
    }

    //Constants

    static final String[] replyMessage = {
        "Request Granted",
        "Request Rejected or Failed",
        "Failed request, can't connect to Identd",
        "Failed request, bad user name"
    };

    static final int SOCKS_VERSION = 4;

    public final static int REQUEST_CONNECT      = 1;
    public final static int REQUEST_BIND         = 2;

    public final static int REPLY_OK             = 90;
    public final static int REPLY_REJECTED       = 91;
    public final static int REPLY_NO_CONNECT     = 92;
    public final static int REPLY_BAD_IDENTD     = 93;

}