/**
 * Title: tnvt.java
 * Copyright: Copyright (c) 2001 Company:
 *
 * @author Kenneth J. Pouncey
 * @version 0.5
 *
 * Description:
 *
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation; either version 2, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this software; see the file COPYING. If not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 */
package org.tn5250j.framework.tn5250;

import static java.lang.Math.max;
import static java.lang.Math.min;
import static org.tn5250j.TN5250jConstants.AID_HELP;
import static org.tn5250j.TN5250jConstants.AID_PRINT;
import static org.tn5250j.TN5250jConstants.CMD_CLEAR_FORMAT_TABLE;
import static org.tn5250j.TN5250jConstants.CMD_CLEAR_UNIT;
import static org.tn5250j.TN5250jConstants.CMD_CLEAR_UNIT_ALTERNATE;
import static org.tn5250j.TN5250jConstants.CMD_READ_INPUT_FIELDS;
import static org.tn5250j.TN5250jConstants.CMD_READ_MDT_FIELDS;
import static org.tn5250j.TN5250jConstants.CMD_READ_MDT_IMMEDIATE_ALT;
import static org.tn5250j.TN5250jConstants.CMD_READ_SCREEN_IMMEDIATE;
import static org.tn5250j.TN5250jConstants.CMD_READ_SCREEN_TO_PRINT;
import static org.tn5250j.TN5250jConstants.CMD_RESTORE_SCREEN;
import static org.tn5250j.TN5250jConstants.CMD_ROLL;
import static org.tn5250j.TN5250jConstants.CMD_SAVE_SCREEN;
import static org.tn5250j.TN5250jConstants.CMD_WRITE_ERROR_CODE;
import static org.tn5250j.TN5250jConstants.CMD_WRITE_ERROR_CODE_TO_WINDOW;
import static org.tn5250j.TN5250jConstants.CMD_WRITE_STRUCTURED_FIELD;
import static org.tn5250j.TN5250jConstants.CMD_WRITE_TO_DISPLAY;
import static org.tn5250j.TN5250jConstants.NR_REQUEST_ERROR;
import static org.tn5250j.TN5250jConstants.PF1;
import static org.tn5250j.TN5250jConstants.PF10;
import static org.tn5250j.TN5250jConstants.PF11;
import static org.tn5250j.TN5250jConstants.PF12;
import static org.tn5250j.TN5250jConstants.PF13;
import static org.tn5250j.TN5250jConstants.PF14;
import static org.tn5250j.TN5250jConstants.PF15;
import static org.tn5250j.TN5250jConstants.PF16;
import static org.tn5250j.TN5250jConstants.PF17;
import static org.tn5250j.TN5250jConstants.PF18;
import static org.tn5250j.TN5250jConstants.PF19;
import static org.tn5250j.TN5250jConstants.PF2;
import static org.tn5250j.TN5250jConstants.PF20;
import static org.tn5250j.TN5250jConstants.PF21;
import static org.tn5250j.TN5250jConstants.PF22;
import static org.tn5250j.TN5250jConstants.PF23;
import static org.tn5250j.TN5250jConstants.PF24;
import static org.tn5250j.TN5250jConstants.PF3;
import static org.tn5250j.TN5250jConstants.PF4;
import static org.tn5250j.TN5250jConstants.PF5;
import static org.tn5250j.TN5250jConstants.PF6;
import static org.tn5250j.TN5250jConstants.PF7;
import static org.tn5250j.TN5250jConstants.PF8;
import static org.tn5250j.TN5250jConstants.PF9;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;
import java.util.Arrays;
import java.util.Properties;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.TimeUnit;
import javax.net.ssl.SSLSocket;

import android.content.Intent;
import android.net.Uri;
import android.util.Log;

import com.five_ten_sg.connectbot.R;
import com.five_ten_sg.connectbot.bean.HostBean;
import com.five_ten_sg.connectbot.service.TerminalBridge;
import com.five_ten_sg.connectbot.service.TerminalManager;
import de.mud.terminal.vt320;

import org.tn5250j.TN5250jConstants;
import org.tn5250j.encoding.CharMappings;
import org.tn5250j.encoding.ICodePage;
import org.tn5250j.framework.transport.SocketConnector;


public final class tnvt implements Runnable {
    private static final String TAG = "tnvt";
    // negotiating commands
    private static final byte IAC = (byte) - 1; // 255 FF
    private static final byte DONT = (byte) - 2; //254 FE
    private static final byte DO = (byte) - 3; //253 FD
    private static final byte WONT = (byte) - 4; //252 FC
    private static final byte WILL = (byte) - 5; //251 FB
    private static final byte SB = (byte) - 6; //250 Sub Begin FA
    private static final byte SE = (byte) - 16; //240 Sub End F0
    private static final byte EOR = (byte) - 17; //239 End of Record EF
    private static final byte TERMINAL_TYPE = (byte) 24; // 18
    private static final byte OPT_END_OF_RECORD = (byte) 25; // 19
    private static final byte TRANSMIT_BINARY = (byte) 0; // 0
    private static final byte QUAL_IS = (byte) 0; // 0
    private static final byte TIMING_MARK = (byte) 6; // 6
    private static final byte NEW_ENVIRONMENT = (byte) 39; // 27
    private static final byte IS = (byte) 0; // 0
    private static final byte SEND = (byte) 1; // 1
    private static final byte INFO = (byte) 2; // 2
    private static final byte VAR = (byte) 0; // 0
    private static final byte VALUE = (byte) 1; // 1
    private static final byte NEGOTIATE_ESC = (byte) 2; // 2
    private static final byte USERVAR = (byte) 3; // 3

    // miscellaneous
    private static final byte ESC = 0x04; // 04

    private Socket sock;
    public  BufferedInputStream bin;
    public  BufferedOutputStream bout;
    private final BlockingQueue<Object> dsq = new ArrayBlockingQueue<Object>(25);
    private Stream5250 bk;
    private DataStreamProducer producer;
    protected Screen5250 screen52;
    private boolean waitingForInput;
    private boolean invited;
    private boolean negotiated = false;
    private Thread me;
    private Thread pthread;
    private int readType;
    private boolean enhanced = true;
    private boolean cursorOn = false;
    private String hostname = "";
    private int port = 23;
    private vt320 buffer;
    private boolean connected = false;
    private boolean support132 = true;
    private ByteArrayOutputStream baosp = null;
    private ByteArrayOutputStream baosrsp = null;
    private int devSeq = -1;
    private String devName;
    private String devNameUsed;
    private KbdTypesCodePages kbdTypesCodePage;
    // WVL - LDC : TR.000300 : Callback scenario from 5250
    private boolean scan; // = false;
    private static int STRSCAN = 1;
    // WVL - LDC : 05/08/2005 : TFX.006253 - support STRPCCMD
    private boolean strpccmd; // = false;
    private String encryption;
    private String user;
    private String password = null;
    private String library;
    private String initialMenu;
    private String program;
    private boolean keepTrucking = true;
    private boolean pendingUnlock = false;
    private boolean[] dataIncluded;
    protected ICodePage codePage;
    private boolean firstScreen;
    private String sslType;
    private WTDSFParser sfParser;
    private TerminalBridge bridge;
    private TerminalManager manager;



    /**
     * @param screen52
     * @param enhanced
     * @param support132
     * @param bridge
     * @param manager
     */
    public tnvt(Screen5250 screen52, boolean enhanced, boolean support132, TerminalBridge bridge, TerminalManager manager) {
        this.screen52   = screen52;
        this.support132 = support132;
        this.enhanced   = enhanced;
        this.bridge     = bridge;
        this.manager    = manager;
        setCodePage("37");
        dataIncluded = new boolean[24];
        baosp = new ByteArrayOutputStream();
        baosrsp = new ByteArrayOutputStream();
    }

    public void showURL(String url) {
        if (url.indexOf("://") < 0) url = "http://" + url;

        Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(url));
        manager.startActivity(intent);
    }

    public String getHostName() {
        return hostname;
    }

    public void setDeviceName(String name) {
        devName = name;
    }

    public String getDeviceName() {
        return devName;
    }

    public String getAllocatedDeviceName() {
        return devNameUsed;
    }

    public boolean isConnected() {
        return connected;
    }

    /**
     * @return true when SSL is used and socket is connected.
     * @see {@link #isConnected()}
     */
    public boolean isSslSocket() {
        if (this.connected && this.sock != null && this.sock instanceof SSLSocket) {
            return true;
        }
        else {
            return false;
        }
    }

    public final void setProxy(String proxyHost, String proxyPort) {
        Properties systemProperties = System.getProperties();
        systemProperties.put("socksProxySet", "true");
        systemProperties.put("socksProxyHost", proxyHost);
        systemProperties.put("socksProxyPort", proxyPort);
        System.setProperties(systemProperties);
        Log.i(TAG, " socks set ");
    }

    private String fixer(String value, String def) {
        if ((value == null) || (value.length() == 0)) return def;

        return value;
    }

    public final boolean connect(HostBean host, String homeDirectory, vt320 buffer) {
        try {
            this.hostname    = host.getHostname();
            this.port        = host.getPort();
            this.buffer      = buffer;
            this.encryption  = fixer(host.getEncryption5250(), "NONE");
            this.user        = host.getUsername();
            this.library     = host.getLibrary();
            this.initialMenu = host.getInitialMenu();
            this.program     = host.getProgram();

            try {
                screen52.getOIA().setInputInhibited(ScreenOIA.INPUTINHIBITED_SYSTEM_WAIT,
                                                    ScreenOIA.OIA_LEVEL_INPUT_INHIBITED, "X - Connecting");
            }
            catch (Exception exc) {
                Log.w(TAG, "setStatus(ON) " + exc.getMessage());
            }

            SocketConnector sc = new SocketConnector();
            sock = sc.createSocket(hostname, port, encryption, homeDirectory, bridge, manager);

            if (sock == null) {
                Log.w(TAG, "I did not get a socket");
                disconnect();
                return false;
            }

            connected = true;
            // used for JDK1.3
            sock.setKeepAlive(true);
            sock.setTcpNoDelay(true);
            sock.setSoLinger(false, 0);
            InputStream in = sock.getInputStream();
            OutputStream out = sock.getOutputStream();
            bin = new BufferedInputStream(in, 8192);
            bout = new BufferedOutputStream(out);
            byte abyte0[];

            while (negotiate(abyte0 = readNegotiations()));

            negotiated = true;

            try {
                screen52.setCursorActive(false);
            }
            catch (Exception excc) {
                Log.w(TAG, "setCursorOff " + excc.getMessage());
            }

            producer = new DataStreamProducer(this, bin, dsq, abyte0);
            pthread = new Thread(producer);
            //         pthread.setPriority(pthread.MIN_PRIORITY);
            pthread.setPriority(Thread.NORM_PRIORITY);
            //          pthread.setPriority(Thread.NORM_PRIORITY / 2);
            pthread.start();

            try {
                screen52.getOIA().setInputInhibited(ScreenOIA.INPUTINHIBITED_NOTINHIBITED,
                                                    ScreenOIA.OIA_LEVEL_INPUT_INHIBITED);
            }
            catch (Exception exc) {
                Log.w(TAG, "setStatus(OFF) " + exc.getMessage());
            }

            keepTrucking = true;
            me = new Thread(this);
            me.start();
        }
        catch (Exception exception) {
            if (exception.getMessage() == null)
                exception.printStackTrace();

            Log.w(TAG, "connect() " + exception.getMessage());

            if (sock == null)
                Log.w(TAG, "I did not get a socket");

            disconnect();
            return false;
        }

        return true;
    }

    public final boolean disconnect() {
        if (!connected) {
            screen52.getOIA().setInputInhibited(ScreenOIA.INPUTINHIBITED_SYSTEM_WAIT,
                                                ScreenOIA.OIA_LEVEL_INPUT_INHIBITED, "X - Disconnected");
            return false;
        }

        if (me != null && me.isAlive()) {
            me.interrupt();
            keepTrucking = false;
            pthread.interrupt();
        }

        screen52.getOIA().setInputInhibited(ScreenOIA.INPUTINHIBITED_SYSTEM_WAIT,
                                            ScreenOIA.OIA_LEVEL_INPUT_INHIBITED, "X - Disconnected");
        screen52.getOIA().setKeyBoardLocked(false);
        pendingUnlock = false;

        try {
            if (sock != null) {
                Log.i(TAG, "Closing socket");
                sock.close();
            }

            if (bin != null) bin.close();

            if (bout != null) bout.close();

            connected   = false;
            firstScreen = false;
            // WVL - LDC : TR.000345 : properly disconnect and clear screen
            // Is this the right place to set screen realestate on disconnect?
            //controller.getScreen().clearAll();
            screen52.goto_XY(0);
            screen52.setCursorActive(false);
            screen52.clearAll();
            screen52.restoreScreen();
        }
        catch (Exception exception) {
            Log.w(TAG, exception.getMessage());
            connected = false;
            devSeq = -1;
            return false;
        }

        devSeq = -1;
        return true;
    }

    private final ByteArrayOutputStream appendByteStream(byte abyte0[]) {
        ByteArrayOutputStream bytearrayoutputstream = new ByteArrayOutputStream();

        for (int i = 0; i < abyte0.length; i++) {
            bytearrayoutputstream.write(abyte0[i]);

            if (abyte0[i] == -1)
                bytearrayoutputstream.write(-1);
        }

        return bytearrayoutputstream;
    }

    private final byte[] readNegotiations() throws IOException {
        int i = bin.read();

        if (i < 0) {
            throw new IOException("Connection closed.");
        }
        else {
            int j = bin.available();
            byte abyte0[] = new byte[j + 1];
            abyte0[0] = (byte) i;
            bin.read(abyte0, 1, j);
            return abyte0;
        }
    }

    private final void writeByte(byte abyte0[]) throws IOException {
        bout.write(abyte0);
        bout.flush();
    }

    //  private final void writeByte(byte byte0) throws IOException {
    //
    //      bout.write(byte0);
    //      bout.flush();
    //  }

    public final void sendHeartBeat() throws IOException {
        byte[] b = { (byte) 0xff, (byte) 0xf1 };
        bout.write(b);
        bout.flush();
    }

    private final void readImmediate(int readType) {
        if (screen52.isStatusErrorCode()) {
            screen52.restoreErrorLine();
            screen52.setStatus(Screen5250.STATUS_ERROR_CODE,
                               Screen5250.STATUS_VALUE_OFF, null);
        }

        if (!enhanced) {
            screen52.setCursorActive(false);
        }

        //      screen52.setStatus(Screen5250.STATUS_SYSTEM,
        //              Screen5250.STATUS_VALUE_ON, null);
        screen52.getOIA().setInputInhibited(ScreenOIA.INPUTINHIBITED_SYSTEM_WAIT,
                                            ScreenOIA.OIA_LEVEL_INPUT_INHIBITED);
        screen52.getOIA().setKeyBoardLocked(true);
        pendingUnlock = false;
        invited = false;
        screen52.getScreenFields().readFormatTable(baosp, readType, codePage);

        try {
            writeGDS(0, 3, baosp.toByteArray());
        }
        catch (IOException ioe) {
            Log.w(TAG, ioe.getMessage());
            baosp.reset();
        }

        baosp.reset();
    }

    public final boolean sendAidKey(int aid) {
        if (screen52.isStatusErrorCode()) {
            screen52.restoreErrorLine();
            screen52.setStatus(Screen5250.STATUS_ERROR_CODE,
                               Screen5250.STATUS_VALUE_OFF, null);
        }

        if (!enhanced) {
            screen52.setCursorActive(false);
        }

        //      screen52.setStatus(Screen5250.STATUS_SYSTEM,
        //              Screen5250.STATUS_VALUE_ON, null);
        screen52.getOIA().setInputInhibited(ScreenOIA.INPUTINHIBITED_SYSTEM_WAIT,
                                            ScreenOIA.OIA_LEVEL_INPUT_INHIBITED);
        screen52.getOIA().setKeyBoardLocked(true);
        pendingUnlock = false;
        invited = false;
        baosp.write(screen52.getCurrentRow());
        baosp.write(screen52.getCurrentCol());
        baosp.write(aid);

        if (dataIncluded(aid))
            screen52.getScreenFields().readFormatTable(baosp, readType,
                    codePage);

        try {
            writeGDS(0, 3, baosp.toByteArray());
        }
        catch (IOException ioe) {
            Log.w(TAG, ioe.getMessage());
            baosp.reset();
            return false;
        }

        baosp.reset();
        return true;
    }

    private boolean dataIncluded(int aid) {
        switch (aid) {
            case PF1:
                return !dataIncluded[0];

            case PF2:
                return !dataIncluded[1];

            case PF3:
                return !dataIncluded[2];

            case PF4:
                return !dataIncluded[3];

            case PF5:
                return !dataIncluded[4];

            case PF6:
                return !dataIncluded[5];

            case PF7:
                return !dataIncluded[6];

            case PF8:
                return !dataIncluded[7];

            case PF9:
                return !dataIncluded[8];

            case PF10:
                return !dataIncluded[9];

            case PF11:
                return !dataIncluded[10];

            case PF12:
                return !dataIncluded[11];

            case PF13:
                return !dataIncluded[12];

            case PF14:
                return !dataIncluded[13];

            case PF15:
                return !dataIncluded[14];

            case PF16:
                return !dataIncluded[15];

            case PF17:
                return !dataIncluded[16];

            case PF18:
                return !dataIncluded[17];

            case PF19:
                return !dataIncluded[18];

            case PF20:
                return !dataIncluded[19];

            case PF21:
                return !dataIncluded[20];

            case PF22:
                return !dataIncluded[21];

            case PF23:
                return !dataIncluded[22];

            case PF24:
                return !dataIncluded[23];

            default:
                return true;
        }
    }

    /**
     * Help request -
     *
     *
     * See notes inside method
     */
    public final void sendHelpRequest() {
        // Client sends header 000D12A0000004000003####F3FFEF
        //       operation code 3
        //       row - first ##
        //       column - second ##
        //       F3 - Help Aid Key
        //      System.out.println("Help request sent");
        baosp.write(screen52.getCurrentRow());
        baosp.write(screen52.getCurrentCol());
        baosp.write(AID_HELP);

        try {
            writeGDS(0, 3, baosp.toByteArray());
        }
        catch (IOException ioe) {
            Log.w(TAG, ioe.getMessage());
        }

        baosp.reset();
    }

    /**
     * Attention Key -
     *
     *
     * See notes inside method
     */
    public final void sendAttentionKey() {
        // Client sends header 000A12A000004400000FFEF
        //    0x40 -> 01000000
        //
        // flags
        // bit 0 - ERR
        // bit 1 - ATN Attention
        // bits 2-4 - reserved
        // bit 5 - SRQ system request
        // bit 6 - TRQ Test request key
        // bit 7 - HLP

        //      System.out.println("Attention key sent");
        try {
            writeGDS(0x40, 0, null);
        }
        catch (IOException ioe) {
            Log.w(TAG, ioe.getMessage());
        }
    }

    /**
     * Opens a dialog and asks the user before sending a request
     *
     * @see {@link #systemRequest(String)}
     */
    public final void systemRequest() {
        String ask = manager.res.getString(R.string.prompt_sys_request);
        String sysreq = bridge.promptHelper.requestStringPrompt(null, ask);
        systemRequest(sysreq);
    }

    /**
     * @param sr - system request option
     * @see {@link #systemRequest(String)}
     */
    public final void systemRequest(char sr) {
        systemRequest(Character.toString(sr));
    }

    /**
     * System request, taken from the rfc1205, 5250 Telnet interface section 4.3
     *
     * @param sr system request option (allowed to be null, but than nothing happens)
     */
    public final void systemRequest(String sr) {
        byte[] bytes = null;

        if ((sr != null) && (sr.length() > 0)) {
            // XXX: Not sure, if this is a sufficient check for 'clear dataq'
            if (sr.charAt(0) == '2') {
                dsq.clear();
            }

            for (int i = 0, l = sr.length(); i < l; i++) {
                baosp.write(codePage.uni2ebcdic(sr.charAt(i)));
            }

            bytes = baosp.toByteArray();
        }

        try {
            writeGDS(4, 0, bytes);
        }
        catch (IOException ioe) {
            Log.i(TAG, ioe.getMessage());
        }

        baosp.reset();
    }

    /**
     * Cancel Invite - taken from the rfc1205 - 5250 Telnet interface section
     * 4.3
     *
     * See notes inside method
     */
    public final void cancelInvite() {
        //      screen52.setStatus(Screen5250.STATUS_SYSTEM,
        //              Screen5250.STATUS_VALUE_ON, null);
        screen52.getOIA().setInputInhibited(ScreenOIA.INPUTINHIBITED_SYSTEM_WAIT,
                                            ScreenOIA.OIA_LEVEL_INPUT_INHIBITED);

        // from rfc1205 section 4.3
        // Server: Sends header with the 000A12A0 00000400 000AFFEF
        // Opcode = Cancel Invite.

        // Client: sends header with the 000A12A0 00000400 000AFFEF
        // Opcode = Cancel Invite to
        // indicate that the work station is
        // no longer invited.
        try {
            writeGDS(0, 10, null);
        }
        catch (IOException ioe) {
            Log.w(TAG, ioe.getMessage());
        }
    }

    public final void hostPrint(int aid) {
        if (screen52.isStatusErrorCode()) {
            screen52.restoreErrorLine();
            screen52.setStatus(Screen5250.STATUS_ERROR_CODE,
                               Screen5250.STATUS_VALUE_OFF, null);
        }

        screen52.setCursorActive(false);
        //      screen52.setStatus(Screen5250.STATUS_SYSTEM,
        //              Screen5250.STATUS_VALUE_ON, null);
        screen52.getOIA().setInputInhibited(ScreenOIA.INPUTINHIBITED_SYSTEM_WAIT,
                                            ScreenOIA.OIA_LEVEL_INPUT_INHIBITED);
        // From client access ip capture
        // it seems to use an operation code of 3 and 4
        // also note that the flag field that says reserved is being sent as
        // well
        // with a value of 0x80
        //
        // I have tried with not setting these flags and sending with 3 or 1
        // there is no effect and I still get a host print screen. Go figure
        //0000: 000D 12A0 0000 0400 8003 1407 F6FFEF
        //0000: 000D 12A0 0000 0400 8001 110E F6FFEF
        //
        // Client sends header 000D12A0000004000003####F6FFEF
        //       operation code 3
        //       row - first ##
        //       column - second ##
        //       F6 - Print Aid Key
        baosp.write(screen52.getCurrentRow());
        baosp.write(screen52.getCurrentCol());
        baosp.write(AID_PRINT); // aid key

        try {
            writeGDS(0, 3, baosp.toByteArray());
        }
        catch (IOException ioe) {
            Log.w(TAG, ioe.getMessage());
        }

        baosp.reset();
    }

    public final void toggleDebug() {
        producer.toggleDebug(codePage);
    }

    // write gerneral data stream
    private final void writeGDS(int flags, int opcode, byte abyte0[])
    throws IOException {
        // Added to fix for JDK 1.4 this was null coming from another method.
        //  There was a weird keyRelease event coming from another panel when
        //  using a key instead of the mouse to select button.
        //  The other method was fixed as well but this check should be here
        // anyway.
        if (bout == null)
            return;

        int length;

        if (abyte0 != null)
            length = abyte0.length + 10;
        else
            length = 10;

        // refer to rfc1205 - 5250 Telnet interface
        // Section 3. Data Stream Format
        // Logical Record Length - 16 bits
        baosrsp.write(length >> 8); // Length LL
        baosrsp.write(length & 0xff); //        LL
        // Record Type - 16 bits
        // It should always be set to '12A0'X to indicate the
        // General Data Stream (GDS) record type.
        baosrsp.write(18); // 0x12
        baosrsp.write(160); // 0xA0
        // the next 16 bits are not used
        baosrsp.write(0); // 0x00
        baosrsp.write(0); // 0x00
        //  The second part is meant to be variable in length
        //  currently this portion is 4 octets long (1 byte or 8 bits for us ;-O)
        baosrsp.write(4); // 0x04
        baosrsp.write(flags); // flags
        // bit 0 - ERR
        // bit 1 - ATN Attention
        // bits 2-4 - reserved
        // bit 5 - SRQ system request
        // bit 6 - TRQ Test request key
        // bit 7 - HLP
        baosrsp.write(0); // reserved - set to 0x00
        baosrsp.write(opcode); // opcode

        if (abyte0 != null)
            baosrsp.write(abyte0, 0, abyte0.length);

        baosrsp = appendByteStream(baosrsp.toByteArray());
        // make sure we indicate no more to be sent
        baosrsp.write(IAC);
        baosrsp.write(EOR);
        baosrsp.writeTo(bout);
        //        byte[] b = new byte[baosrsp.size()];
        //        b = baosrsp.toByteArray();
        //      dump(b);
        bout.flush();
        //      baos = null;
        baosrsp.reset();
    }

    protected final int getOpCode() {
        return bk.getOpCode();
    }

    //  private final void sendNotify() throws IOException {
    //
    //      writeGDS(0, 0, null);
    //  }

    protected boolean[] getActiveAidKeys() {
        boolean aids[] = new boolean[dataIncluded.length];
        System.arraycopy(dataIncluded, 0, aids, 0, dataIncluded.length);
        return aids;
    }

    private final void setInvited() {
        Log.d(TAG, "invited");

        if (!screen52.isStatusErrorCode())
            screen52.getOIA().setInputInhibited(ScreenOIA.INPUTINHIBITED_NOTINHIBITED,
                                                ScreenOIA.OIA_LEVEL_INPUT_INHIBITED);

        invited = true;
    }

    // WVL - LDC : 05/08/2005 : TFX.006253 - Support STRPCCMD
    private void strpccmd() {
        try {
            int str = 11;
            char c;
            ScreenPlanes planes = screen52.getPlanes();
            c = planes.getChar(str);
            boolean waitFor = !(c == 'a');
            StringBuffer command = new StringBuffer();

            for (int i = str + 1; i < 132; i++) {
                c = planes.getChar(i);

                if (Character.isISOControl(c))
                    c = ' ';

                command.append(c);
            }

            String cmd = command.toString().trim();
            run(cmd, waitFor);
        }
        finally {
            strpccmd = false;
            screen52.sendKeys(TN5250jConstants.MNEMONIC_ENTER);
        }
    }

    // WVL - LDC : 05/08/2005 : TFX.006253 - Support STRPCCMD
    private void run(String cmd, boolean waitFor) {
        try {
            Log.d(TAG, "RUN cmd = " + cmd);
            Log.d(TAG, "RUN wait = " + waitFor);
            Runtime r = Runtime.getRuntime();
            Process p = r.exec(cmd);

            if (waitFor) {
                int result = p.waitFor();
                Log.d(TAG, "RUN result = " + result);
            }
        }
        catch (Throwable t) {
            Log.e(TAG, "exception", t);
        }
    }


    // WVL - LDC : TR.000300 : Callback scenario from 5250
    /**
     * Activate or deactivate the command scanning behaviour.
     *
     * @param scan
     *            if true, scanning is enabled; disabled otherwise.
     *
     * @see scan4Cmd()
     */
    public void setScanningEnabled(boolean scan) {
        this.scan = scan;
    }

    // WVL - LDC : TR.000300 : Callback scenario from 5250
    /**
     * Checks whether command scanning is enabled.
     *
     * @return true is command scanning is enabled; false otherwise.
     */
    public boolean isScanningEnabled() {
        return this.scan;
    }

    // WVL - LDC : TR.000300 : Callback scenario from 5250
    /**
     * When command scanning is activated, the terminal reads the first and
     * second character in the datastream (the zero position allows to
     * devisualize the scan stream). If the sequence <code>#!</code> is
     * encountered and if this sequence is <strong>not </strong> followed by a
     * blank character, the {@link parseCommand(ScreenChar[])}is called.
     */
    private void scan() {
        //     System.out.println("Checking command : " +
        // screen52.screen[1].getChar() + screen52.screen[2].getChar());
        //      ScreenChar[] screen = screen52.screen;
        ScreenPlanes planes = screen52.getPlanes();

        if ((planes.getChar(STRSCAN) == '#')
                && (planes.getChar(STRSCAN + 1) == '!')
                && (planes.getChar(STRSCAN + 2) != ' ')) {
            try {
                parseCommand();
            }
            catch (Throwable t) {
                Log.i(TAG, "Exec cmd: " + t.getMessage());
                t.printStackTrace();
            }
        }
    }

    // WVL - LDC : TR.000300 : Callback scenario from 5250
    /**
     * The screen is parsed starting from second position until a white space is
     * encountered. When found the Session#execCommand(String, int) is
     * called with the parsed string. The position immediately following the
     * encountered white space, separating the command from the rest of the
     * screen, is passed as starting index.
     *
     * Note that the character at the starting position can potentially be a
     * white space itself. The starting position in <code>execCommand</code>
     * provided to make the scanning sequence more flexible. We'd like for
     * example to embed also a <code>+</code> or <code>-</code> sign to
     * indicate whether the tnvt should trigger a repaint or not. This would
     * allow the flashing of command sequences without them becoming visible.
     *
     * <ul>
     * <li><strong>PRE </strong> The screen character at position
     * <code>STRSCAN + 2</code> is not a white space.</li>
     * </ul>
     */
    private void parseCommand() {
        // Search for the command i.e. the first token in the stream
        // after the #! sequence separated by a space from the rest
        // of the screen.
        char[] screen = screen52.getScreenAsChars();

        for (int s = STRSCAN + 2, i = s; i < screen.length; i++) {
            if (screen[i] == ' ') {
                String command = new String(screen, s, i - s);
                // Skip all white spaces between the command and the rest of
                // the screen.
                //for (; (i < screen.length) && (screen[i] == ' '); i++);
                String remainder = new String(screen, i + 1, screen.length
                                              - (i + 1));
                //controller.fireScanned(command, remainder);
                Log.i(TAG, "trying to run " + command + " " + remainder);
                break;
            }
        }
    }

    public void run() {
        if (enhanced) sfParser = new WTDSFParser(this);

        bk = new Stream5250();

        while (keepTrucking) {
            try {
                Object e = dsq.take();
                bk.initialize((byte[])e);
            }
            catch (InterruptedException ie) {
                Log.w(TAG, "   vt thread interrupted and stopping ");
                keepTrucking = false;
                continue;
            }

            invited = false;
            screen52.setCursorActive(false);

            if (bk == null) continue;

            switch (bk.getOpCode()) {
                case 00:
                    Log.d(TAG, "No operation");
                    break;

                case 1:
                    Log.d(TAG, "Invite Operation");
                    parseIncoming();
                    pendingUnlock = true;
                    cursorOn = true;
                    setInvited();
                    break;

                case 2:
                    Log.d(TAG, "Output Only");
                    parseIncoming();
                    screen52.updateDirty();
                    break;

                case 3:
                    Log.d(TAG, "Put/Get Operation");
                    parseIncoming();
                    setInvited();

                    if (!firstScreen) {
                        firstScreen = true;
                        //controller.fireSessionChanged(TN5250jConstants.STATE_CONNECTED);
                    }

                    break;

                case 4:
                    Log.d(TAG, "Save Screen Operation");
                    parseIncoming();
                    break;

                case 5:
                    Log.d(TAG, "Restore Screen Operation");
                    parseIncoming();
                    break;

                case 6:
                    Log.d(TAG, "Read Immediate");
                    sendAidKey(0);
                    break;

                case 7:
                    Log.d(TAG, "Reserved");
                    break;

                case 8:
                    Log.d(TAG, "Read Screen Operation");

                    try {
                        readScreen();
                    }
                    catch (IOException ex) {
                        Log.w(TAG, ex.getMessage());
                    }

                    break;

                case 9:
                    Log.d(TAG, "Reserved");
                    break;

                case 10:
                    Log.d(TAG, "Cancel Invite Operation");
                    cancelInvite();
                    break;

                case 11:
                    Log.d(TAG, "Turn on message light");
                    screen52.getOIA().setMessageLightOn();
                    screen52.setCursorActive(true);
                    break;

                case 12:
                    Log.d(TAG, "Turn off Message light");
                    screen52.getOIA().setMessageLightOff();
                    screen52.setCursorActive(true);
                    break;

                default:
                    break;
            }

            if (screen52.isUsingGuiInterface())
                screen52.drawFields();

            try {
                if (!strpccmd) {
                    screen52.updateDirty();
                }
                else {
                    strpccmd();
                }
            }
            catch (Exception exd) {
                Log.w(TAG, " tnvt.run: " + exd.getMessage());
                exd.printStackTrace();
            }

            if (pendingUnlock && !screen52.isStatusErrorCode()) {
                screen52.getOIA().setKeyBoardLocked(false);
                pendingUnlock = false;
            }

            if (cursorOn && !screen52.getOIA().isKeyBoardLocked()) {
                screen52.setCursorActive(true);
                cursorOn = false;
                buffer.testChanged();
            }
        }
    }

    public void dumpStuff() {
        Log.d(TAG, " Pending unlock " + pendingUnlock);
        Log.d(TAG, " Status Error " + screen52.isStatusErrorCode());
        Log.d(TAG, " Keyboard Locked " + screen52.getOIA().isKeyBoardLocked());
        Log.d(TAG, " Cursor On " + cursorOn);
        Log.d(TAG, " Cursor Active " + screen52.cursorActive);
    }


    private final void readScreen() throws IOException {
        int rows = screen52.getRows();
        int cols = screen52.getColumns();
        byte abyte0[] = new byte[rows * cols];
        fillScreenArray(abyte0, rows, cols);
        writeGDS(0, 0, abyte0);
        abyte0 = null;
    }

    private final void fillScreenArray(byte[] sa, int rows, int cols) {
        int la = 32;
        int sac = 0;
        int len = rows * cols;
        ScreenPlanes planes = screen52.planes;

        for (int y = 0; y < len; y++) { // save the screen data
            if (planes.isAttributePlace(y)) {
                la = planes.getCharAttr(y);
                sa[sac++] = (byte) la;
            }
            else {
                if (planes.getCharAttr(y) != la) {
                    la = planes.getCharAttr(y);
                    sac = max(sac--, 0);
                    sa[sac++] = (byte) la;
                }

                //LDC: Check to see if it is an displayable character. If not,
                //  do not convert the character.
                //  The characters on screen are in unicode
                //sa[sac++] =
                // (byte)codePage.uni2ebcdic(screen52.screen[y].getChar());
                char ch = planes.getChar(y);
                byte byteCh = (byte) ch;

                if (isDataUnicode(ch))
                    byteCh = codePage.uni2ebcdic(ch);

                sa[min(sac++, len - 1)] = byteCh;
            }
        }
    }

    private final void fillRegenerationBuffer(ByteArrayOutputStream sc, int rows, int cols)
    throws IOException {
        int la = 32;
        int sac = 0;
        int len = rows * cols;
        ScreenPlanes planes = screen52.planes;
        byte[] sa = new byte[len];

        try {
            boolean guiExists = sfParser != null && sfParser.isGuisExists();

            for (int y = 0; y < len; y++) { // save the screen data
                if (guiExists) {
                    byte[] guiSeg = sfParser.getSegmentAtPos(y);

                    if (guiSeg != null) {
                        //Log.i(TAG," gui saved at " + y + " - " + screen52.getRow(y) + "," +
                        //    screen52.getCol(y));
                        byte[] gsa = new byte[sa.length + guiSeg.length + 2];
                        System.arraycopy(sa, 0, gsa, 0, sa.length);
                        System.arraycopy(guiSeg, 0, gsa, sac + 2, guiSeg.length);
                        sa = new byte[gsa.length];
                        System.arraycopy(gsa, 0, sa, 0, gsa.length);
                        sa[sac++] = (byte)0x04;
                        sa[sac++] = (byte)0x11;
                        sac += guiSeg.length;
                        //y--;
                        //               continue;
                    }
                }

                if (planes.isAttributePlace(y)) {
                    la = planes.getCharAttr(y);
                    sa[sac++] = (byte) la;
                }
                else {
                    if (planes.getCharAttr(y) != la) {
                        la = planes.getCharAttr(y);
                        sac = max(sac--, 0);
                        sa[sac++] = (byte) la;
                    }

                    //LDC: Check to see if it is an displayable character. If not,
                    //  do not convert the character.
                    //  The characters on screen are in unicode
                    //sa[sac++] =
                    // (byte)codePage.uni2ebcdic(screen52.screen[y].getChar());
                    char ch = planes.getChar(y);
                    byte byteCh = (byte) ch;

                    if (isDataUnicode(ch))
                        byteCh = codePage.uni2ebcdic(ch);

                    sa[min(sac++, len - 1)] = byteCh;
                }
            }
        }
        catch (Exception exc) {
            Log.i(TAG, exc.getMessage());
            exc.printStackTrace();
        }

        sc.write(sa);
    }

    public final void saveScreen() throws IOException {
        ByteArrayOutputStream sc = new ByteArrayOutputStream();
        sc.write(4);
        sc.write(0x12); // 18
        sc.write(0); // 18
        sc.write(0); // 18
        sc.write((byte) screen52.getRows()); // store the current size
        sc.write((byte) screen52.getColumns()); //    ""
        int cp = screen52.getCurrentPos(); // save off current position
        // fix below submitted by Mitch Blevins
        //int cp = screen52.getScreenFields().getCurrentFieldPos();
        // save off current position
        sc.write((byte)(cp >> 8 & 0xff));  //    ""
        sc.write((byte)(cp & 0xff));  //    ""
        sc.write((byte)(screen52.homePos >> 8 & 0xff));  // save home pos
        sc.write((byte)(screen52.homePos & 0xff));  //    ""
        int rows = screen52.getRows(); // store the current size
        int cols = screen52.getColumns(); //    ""
        //      byte[] sa = new byte[rows * cols];
        fillRegenerationBuffer(sc, rows, cols);
        //      fillScreenArray(sa, rows, cols);
        //
        //      sc.write(sa);
        //      sa = null;
        int sizeFields = screen52.getScreenFields().getSize();
        sc.write((byte)(sizeFields >> 8 & 0xff));  //    ""
        sc.write((byte)(sizeFields & 0xff));  //    ""

        if (sizeFields > 0) {
            int x = 0;
            int s = screen52.getScreenFields().getSize();
            ScreenField sf = null;

            while (x < s) {
                sf = screen52.getScreenFields().getField(x);
                sc.write((byte) sf.getAttr()); // attribute
                int sp = sf.startPos();
                sc.write((byte)(sp >> 8 & 0xff));  //    ""
                sc.write((byte)(sp & 0xff));  //    ""

                if (sf.mdt)
                    sc.write((byte) 1);
                else
                    sc.write((byte) 0);

                sc.write((byte)(sf.getLength() >> 8 & 0xff));  //    ""
                sc.write((byte)(sf.getLength() & 0xff));  //    ""
                sc.write((byte) sf.getFFW1() & 0xff);
                sc.write((byte) sf.getFFW2() & 0xff);
                sc.write((byte) sf.getFCW1() & 0xff);
                sc.write((byte) sf.getFCW2() & 0xff);
                Log.d(TAG, "Saved ");
                Log.d(TAG, sf.toString());
                x++;
            }

            sf = null;
        }

        // The following two lines of code looks to have caused all sorts of
        //    problems so for now we have commented them out.
        //      screen52.getScreenFields().setCurrentField(null); // set it to null
        // for GC ?
        //      screen52.clearTable();

        try {
            writeGDS(0, 3, sc.toByteArray());
        }
        catch (IOException ioe) {
            Log.w(TAG, ioe.getMessage());
        }

        sc = null;
        Log.d(TAG, "Save Screen end ");
    }

    /**
     *
     * @throws IOException
     */
    public final void restoreScreen() throws IOException {
        int which = 0;
        ScreenPlanes planes = screen52.planes;

        try {
            Log.d(TAG, "Restore ");
            bk.getNextByte();
            bk.getNextByte();
            int rows = bk.getNextByte() & 0xff;
            int cols = bk.getNextByte() & 0xff;
            int pos = bk.getNextByte() << 8 & 0xff00; // current position
            pos |= bk.getNextByte() & 0xff;
            int hPos = bk.getNextByte() << 8 & 0xff00; // home position
            hPos |= bk.getNextByte() & 0xff;

            if ((rows != screen52.getRows()) || (cols != screen52.getColumns()))
                screen52.setRowsCols(rows, cols);

            screen52.clearAll(); // initialize what we currenty have

            if (sfParser != null && sfParser.isGuisExists())
                sfParser.clearGuiStructs();

            int b = 32;
            int la = 32;
            int len = rows * cols;

            for (int y = 0; y < len; y++) {
                b = bk.getNextByte();

                if (b == 0x04) {
                    Log.i(TAG, " gui restored at " + y + " - " + screen52.getRow(y) + "," +
                          screen52.getCol(y));
                    int command = bk.getNextByte();
                    byte[] seg = bk.getSegment();

                    if (seg.length > 0) {
                        screen52.goto_XY(y);
                        sfParser.parseWriteToDisplayStructuredField(seg);
                    }

                    y--;
                    //                    screen52.goto_XY(y);
                }
                else {
                    //              b = bk.getNextByte();
                    if (planes.isUseGui(y))
                        continue;

                    if (isAttribute(b)) {
                        planes.setScreenCharAndAttr(y, planes.getChar(y), b, true);
                        la = b;
                    }
                    else {
                        //LDC - 12/02/2003 - Check to see if it is an displayable
                        // character. If not,
                        //  do not convert the character.
                        //  The characters on screen are in unicode
                        char ch = (char) b;

                        if (isDataEBCDIC(b))
                            ch = codePage.ebcdic2uni(b);

                        planes.setScreenCharAndAttr(y, ch, la, false);
                    }
                }
            }

            int numFields = bk.getNextByte() << 8 & 0xff00;
            numFields |= bk.getNextByte() & 0xff;
            Log.d(TAG, "number of fields " + numFields);

            if (numFields > 0) {
                int x = 0;
                int attr = 0;
                int fPos = 0;
                int fLen = 0;
                int ffw1 = 0;
                int ffw2 = 0;
                int fcw1 = 0;
                int fcw2 = 0;
                boolean mdt = false;
                ScreenField sf = null;

                while (x < numFields) {
                    attr = bk.getNextByte();
                    fPos = bk.getNextByte() << 8 & 0xff00;
                    fPos |= bk.getNextByte() & 0xff;

                    if (bk.getNextByte() == 1)
                        mdt = true;
                    else
                        mdt = false;

                    fLen = bk.getNextByte() << 8 & 0xff00;
                    fLen |= bk.getNextByte() & 0xff;
                    ffw1 = bk.getNextByte();
                    ffw2 = bk.getNextByte();
                    fcw1 = bk.getNextByte();
                    fcw2 = bk.getNextByte();
                    sf = screen52.getScreenFields().setField(attr,
                            screen52.getRow(fPos), screen52.getCol(fPos), fLen,
                            ffw1, ffw2, fcw1, fcw2);

                    while (fLen-- > 0) {
                        // now we set the field plane attributes
                        planes.setScreenFieldAttr(fPos++, ffw1);
                    }

                    if (mdt) {
                        sf.setMDT();
                        screen52.getScreenFields().setMasterMDT();
                    }

                    Log.d(TAG, "/nRestored ");
                    Log.d(TAG, sf.toString());
                    x++;
                }
            }

            //  Redraw the gui fields if we are in gui mode
            if (screen52.isUsingGuiInterface())
                screen52.drawFields();

            screen52.restoreScreen(); // display the screen
            //  The position was saved with currentPos which 1,1 offset of the
            //     screen position.
            //  The setPendingInsert is the where the cursor position will be
            //  displayed after the restore.
            screen52.setPendingInsert(true, screen52.getRow(pos + cols), screen52
                                      .getCol(pos + cols));
            //  We need to offset the pos by -1 since the position is 1,1 based
            //    and the goto_XY is 0,0 based.
            screen52.goto_XY(pos - 1);
            screen52.isInField();
            //          //  Redraw the gui fields if we are in gui mode
            //          if (screen52.isUsingGuiInterface())
            //              screen52.drawFields();
        }
        catch (Exception e) {
            Log.w(TAG, "error restoring screen " + which + " with "
                  + e.getMessage());
        }
    }

    public final boolean waitingForInput() {
        return waitingForInput;
    }

    private void parseIncoming() {
        boolean done = false;
        boolean error = false;

        try {
            while (bk.hasNext() && !done) {
                byte b = bk.getNextByte();

                switch (b) {
                    case 0:
                    case 1:
                        break;

                    case CMD_SAVE_SCREEN: // 0x02 2 Save Screen
                    case 3: // 0x03 3 Save Partial Screen
                        Log.d(TAG, "save screen partial");
                        saveScreen();
                        break;

                    case ESC: // ESCAPE
                        break;

                    case 7: // audible bell
                        manager.playBeep();
                        bk.getNextByte();
                        bk.getNextByte();
                        break;

                    case CMD_WRITE_TO_DISPLAY: // 0x11 17 write to display
                        error = writeToDisplay(true);

                        // WVL - LDC : TR.000300 : Callback scenario from 5250
                        // Only scan when WRITE_TO_DISPLAY operation (i.e. refill
                        // screen buffer)
                        // has been issued!
                        if (scan)
                            scan();

                        break;

                    case CMD_RESTORE_SCREEN: // 0x12 18 Restore Screen
                    case 13: // 0x13 19 Restore Partial Screen
                        Log.d(TAG, "restore screen partial");
                        restoreScreen();
                        break;

                    case CMD_CLEAR_UNIT_ALTERNATE: // 0x20 32 clear unit alternate
                        int param = bk.getNextByte();

                        if (param != 0) {
                            Log.d(TAG, " clear unit alternate error "
                                  + Integer.toHexString(param));
                            sendNegResponse(NR_REQUEST_ERROR, 03, 01, 05,
                                            " clear unit alternate not supported");
                            done = true;
                        }
                        else {
                            if (screen52.getRows() != 27)
                                screen52.setRowsCols(27, 132);

                            screen52.clearAll();

                            if (sfParser != null && sfParser.isGuisExists())
                                sfParser.clearGuiStructs();
                        }

                        break;

                    case CMD_WRITE_ERROR_CODE: // 0x21 33 Write Error Code
                        writeErrorCode();
                        error = writeToDisplay(false);
                        break;

                    case CMD_WRITE_ERROR_CODE_TO_WINDOW: // 0x22 34
                        // Write Error Code to window
                        writeErrorCodeToWindow();
                        error = writeToDisplay(false);
                        break;

                    case CMD_READ_SCREEN_IMMEDIATE: // 0x62 98
                    case CMD_READ_SCREEN_TO_PRINT: // 0x66 102 read screen to print
                        readScreen();
                        break;

                    case CMD_CLEAR_UNIT: // 64 0x40 clear unit
                        if (screen52.getRows() != 24)
                            screen52.setRowsCols(24, 80);

                        screen52.clearAll();

                        if (sfParser != null && sfParser.isGuisExists())
                            sfParser.clearGuiStructs();

                        break;

                    case CMD_CLEAR_FORMAT_TABLE: // 80 0x50 Clear format table
                        screen52.clearTable();
                        break;

                    case CMD_READ_INPUT_FIELDS: //0x42 66 read input fields
                    case CMD_READ_MDT_FIELDS: // 0x52 82 read MDT Fields
                        bk.getNextByte();
                        bk.getNextByte();
                        readType = b;
                        screen52.goHome();
                        // do nothing with the cursor here it is taken care of
                        //   in the main loop.
                        //////////////// screen52.setCursorOn();
                        waitingForInput = true;
                        pendingUnlock = true;
                        //                  screen52.setKeyboardLocked(false);
                        break;

                    case CMD_READ_MDT_IMMEDIATE_ALT: // 0x53 83
                        readType = b;
                        //                  screen52.goHome();
                        //                  waitingForInput = true;
                        //                  screen52.setKeyboardLocked(false);
                        readImmediate(readType);
                        break;

                    case CMD_WRITE_STRUCTURED_FIELD: // 243 0xF3 -13 Write
                        // structured field
                        writeStructuredField();
                        break;

                    case CMD_ROLL: // 0x23 35 Roll Not sure what it does right now
                        int updown = bk.getNextByte();
                        int topline = bk.getNextByte();
                        int bottomline = bk.getNextByte();
                        screen52.rollScreen(updown, topline, bottomline);
                        break;

                    default:
                        done = true;
                        sendNegResponse(NR_REQUEST_ERROR, 03, 01, 01,
                                        "parseIncoming");
                        break;
                }

                if (error)
                    done = true;
            }
        }
        catch (Exception exc) {
            Log.w(TAG, "incoming " + exc.getMessage());
        }
    }

    /**
     * This routine handles sending negative responses back to the host.
     *
     * You can find a description of the types of responses to be sent back by
     * looking at section 12.4 of the 5250 Functions Reference manual
     *
     *
     * @param cat
     * @param modifier
     * @param uByte1
     * @param uByte2
     * @param from
     *
     */
    protected void sendNegResponse(int cat, int modifier, int uByte1,
                                   int uByte2, String from) {
        try {
            int os = bk.getByteOffset(-1) & 0xf0;
            int cp = (bk.getCurrentPos() - 1);
            Log.i(TAG, "invalid " + from + " command " + os
                  + " at pos " + cp);
        }
        catch (Exception e) {
            Log.w(TAG, "Send Negative Response error " + e.getMessage());
        }

        baosp.write(cat);
        baosp.write(modifier);
        baosp.write(uByte1);
        baosp.write(uByte2);

        try {
            writeGDS(128, 0, baosp.toByteArray());
        }
        catch (IOException ioe) {
            Log.w(TAG, ioe.getMessage());
        }

        baosp.reset();
    }

    public void sendNegResponse2(int ec) {
        screen52.setPrehelpState(true, true, false);
        baosp.write(0x00);
        baosp.write(ec);

        try {
            writeGDS(1, 0, baosp.toByteArray());
        }
        catch (IOException ioe) {
            Log.w(TAG, ioe.getMessage());
        }

        baosp.reset();
    }

    private boolean writeToDisplay(boolean controlsExist) {
        boolean error = false;
        boolean done = false;
        int attr;
        byte control0 = 0;
        byte control1 = 0;
        int saRows = screen52.getRows();
        int saCols = screen52.getColumns();

        try {
            if (controlsExist) {
                control0 = bk.getNextByte();
                control1 = bk.getNextByte();
                processCC0(control0);
            }

            while (bk.hasNext() && !done) {
                //            pos = bk.getCurrentPos();
                //            int rowc = screen52.getCurrentRow();
                //            int colc = screen52.getCurrentCol();
                byte bytebk = bk.getNextByte();

                switch (bytebk) {
                    case 1: // SOH - Start of Header Order
                        Log.d(TAG, "SOH - Start of Header Order");
                        error = processSOH();
                        break;

                    case 02: // RA - Repeat to address
                        Log.d(TAG, "RA - Repeat to address");
                        int row = screen52.getCurrentRow();
                        int col = screen52.getCurrentCol();
                        int toRow = bk.getNextByte();
                        int toCol = bk.getNextByte() & 0xff;

                        if (toRow >= row) {
                            int repeat = bk.getNextByte();

                            // a little intelligence here I hope
                            if (row == 1 && col == 2 && toRow == screen52.getRows()
                                    && toCol == screen52.getColumns())
                                screen52.clearScreen();
                            else {
                                if (repeat != 0) {
                                    //LDC - 13/02/2003 - convert it to unicode
                                    repeat = codePage.ebcdic2uni(repeat);
                                    //repeat = getASCIIChar(repeat);
                                }

                                int times = ((toRow * screen52.getColumns()) + toCol)
                                            - ((row * screen52.getColumns()) + col);

                                while (times-- >= 0) {
                                    screen52.setChar(repeat);
                                }
                            }
                        }
                        else {
                            sendNegResponse(NR_REQUEST_ERROR, 0x05, 0x01, 0x23,
                                            " RA invalid");
                            error = true;
                        }

                        break;

                    case 03: // EA - Erase to address
                        Log.d(TAG, "EA - Erase to address");
                        int EArow = screen52.getCurrentRow();
                        int EAcol = screen52.getCurrentCol();
                        int toEARow = bk.getNextByte();
                        int toEACol = bk.getNextByte() & 0xff;
                        int EALength = bk.getNextByte() & 0xff;

                        while (--EALength > 0) {
                            bk.getNextByte();
                        }

                        char EAAttr = (char) 0;

                        // a little intelligence here I hope
                        if (EArow == 1 && EAcol == 2
                                && toEARow == screen52.getRows()
                                && toEACol == screen52.getColumns())
                            screen52.clearScreen();
                        else {
                            int times = ((toEARow * screen52.getColumns()) + toEACol)
                                        - ((EArow * screen52.getColumns()) + EAcol);

                            while (times-- >= 0) {
                                screen52.setChar(EAAttr);
                            }
                        }

                        break;

                    case 04: // Command - Escape
                        Log.d(TAG, "Command - Escape");
                        done = true;
                        break;

                    case 16: // TD - Transparent Data
                        Log.d(TAG, "TD - Transparent Data");
                        int j = (bk.getNextByte() & 0xff) << 8 | bk.getNextByte()
                                & 0xff; // length
                        break;

                    case 17: // SBA - set buffer address order (row column)
                        //Log.d(TAG,"SBA - set buffer address order (row column)");
                        int saRow = bk.getNextByte();
                        int saCol = bk.getNextByte() & 0xff;

                        // make sure it is in bounds
                        if (saRow >= 0 && saRow <= screen52.getRows() && saCol >= 0
                                && saCol <= screen52.getColumns()) {
                            screen52.setCursor(saRow, saCol); // now set screen
                            // position for output
                        }
                        else {
                            sendNegResponse(NR_REQUEST_ERROR, 0x05, 0x01, 0x22,
                                            "invalid row/col order" + " saRow = " + saRow
                                            + " saRows = " + screen52.getRows()
                                            + " saCol = " + saCol);
                            error = true;
                        }

                        break;

                    case 18: // WEA - Extended Attribute
                        Log.d(TAG, "WEA - Extended Attribute");
                        bk.getNextByte();
                        bk.getNextByte();
                        break;

                    case 19: // IC - Insert Cursor
                        Log.d(TAG, "IC - Insert Cursor");
                        int icX = bk.getNextByte();
                        int icY = bk.getNextByte() & 0xff;

                        if (icX >= 0 && icX <= saRows && icY >= 0 && icY <= saCols) {
                            Log.d(TAG, " IC " + icX + " " + icY);
                            screen52.setPendingInsert(true, icX, icY);
                        }
                        else {
                            sendNegResponse(NR_REQUEST_ERROR, 0x05, 0x01, 0x22,
                                            " IC/IM position invalid ");
                            error = true;
                        }

                        break;

                    case 20: // MC - Move Cursor
                        Log.d(TAG, "MC - Move Cursor");
                        int imcX = bk.getNextByte();
                        int imcY = bk.getNextByte() & 0xff;

                        if (imcX >= 0 && imcX <= saRows && imcY >= 0
                                && imcY <= saCols) {
                            Log.d(TAG, " MC " + imcX + " " + imcY);
                            screen52.setPendingInsert(false, imcX, imcY);
                        }
                        else {
                            sendNegResponse(NR_REQUEST_ERROR, 0x05, 0x01, 0x22,
                                            " IC/IM position invalid ");
                            error = true;
                        }

                        break;

                    case 21: // WTDSF - Write To Display Structured Field order
                        Log.d(TAG, "WTDSF - Write To Display Structured Field order");
                        byte[] seg = bk.getSegment();
                        error = sfParser.parseWriteToDisplayStructuredField(seg);
                        break;

                    case 29: // SF - Start of Field
                        Log.d(TAG, "SF - Start of Field");
                        int fcw1 = 0;
                        int fcw2 = 0;
                        int ffw1 = 0;
                        int ffw0 = bk.getNextByte() & 0xff; // FFW

                        if ((ffw0 & 0x40) == 0x40) {
                            ffw1 = bk.getNextByte() & 0xff; // FFW 1
                            fcw1 = bk.getNextByte() & 0xff; // check for field

                            // control word

                            // check if the first fcw1 is an 0x81 if it is then get
                            // the next pair for checking
                            if (fcw1 == 0x81) {
                                bk.getNextByte();
                                fcw1 = bk.getNextByte() & 0xff; // check for field
                                // control word
                            }

                            if (!isAttribute(fcw1)) {
                                fcw2 = bk.getNextByte() & 0xff; // FCW 2
                                attr = bk.getNextByte() & 0xff; // attribute field

                                while (!isAttribute(attr)) {
                                    Log.i(TAG, Integer.toHexString(fcw1) + " "
                                          + Integer.toHexString(fcw2)
                                          + " ");
                                    Log.i(TAG, Integer.toHexString(attr)
                                          + " "
                                          + Integer.toHexString(bk
                                                                .getNextByte() & 0xff));
                                    attr = bk.getNextByte() & 0xff; // attribute field
                                }
                            }
                            else {
                                attr = fcw1; // attribute of field
                                fcw1 = 0;
                            }
                        }
                        else {
                            attr = ffw0;
                        }

                        int fLength = (bk.getNextByte() & 0xff) << 8
                                      | bk.getNextByte() & 0xff;
                        screen52.addField(attr, fLength, ffw0, ffw1, fcw1, fcw2);
                        break;

                    // WVL - LDC : 05/08/2005 : TFX.006253 - Support STRPCCMD
                    case -128: //STRPCCMD
                        //          if (screen52.getCurrentPos() == 82) {
                        Log.d(TAG, "STRPCCMD got a -128 command at " + screen52.getCurrentPos());
                        StringBuffer value = new StringBuffer();
                        int b;
                        char c;
                        int[] pco = new int[9];
                        int[] pcoOk = {0xfc, 0xd7, 0xc3, 0xd6, 0x40, 0x83, 0x80, 0xa1, 0x80};

                        for (int i = 0; i < 9; i++) {
                            b = bk.getNextByte();
                            pco[i] = ((b & 0xff));
                            c = codePage.ebcdic2uni(b);
                            value.append(c);
                        }

                        // Check "PCO-String"
                        if (Arrays.equals(pco, pcoOk)) {
                            strpccmd = true;
                        }

                        // we return in the stream to have all chars
                        // arrive at the screen for later processing
                        for (int i = 0; i < 9; i++)
                            bk.setPrevByte();

                    //}
                    // no break: so every chars arrives
                    // on the screen for later parsing
                    //break;

                    default: // all others must be output to screen
                        //Log.d(TAG,"all others must be output to screen");
                        byte byte0 = bk.getByteOffset(-1);

                        if (isAttribute(byte0)) {
                            screen52.setAttr(byte0);
                        }
                        else {
                            if (!screen52.isStatusErrorCode()) {
                                if (!isDataEBCDIC(byte0)) {
                                    //                           if (byte0 == 255) {
                                    //                              sendNegResponse(NR_REQUEST_ERROR,0x05,0x01,0x42,
                                    //                              " Attempt to send FF to screen");
                                    //                           }
                                    //                           else
                                    screen52.setChar(byte0);
                                }
                                else
                                    //LDC - 13/02/2003 - Convert it to unicode
                                    //screen52.setChar(getASCIIChar(byte0));
                                    screen52.setChar(codePage.ebcdic2uni(byte0));
                            }
                            else {
                                if (byte0 == 0)
                                    screen52.setChar(byte0);
                                else
                                    //LDC - 13/02/2003 - Convert it to unicode
                                    //screen52.setChar(getASCIIChar(byte0));
                                    screen52.setChar(codePage.ebcdic2uni(byte0));
                            }
                        }

                        break;
                }

                if (error)
                    done = true;
            }
        }
        catch (Exception e) {
            Log.w(TAG, "write to display " + e.getMessage());
            e.printStackTrace();
        }

        ;

        processCC1(control1);

        return error;
    }

    private boolean processSOH() throws Exception {
        int l = bk.getNextByte(); // length
        Log.d(TAG, " byte 0 " + l);

        if (l > 0 && l <= 7) {
            bk.getNextByte(); // flag byte 2
            bk.getNextByte(); // reserved
            bk.getNextByte(); // resequence fields
            screen52.clearTable();

            // well that is the first time I have seen this. This fixes a
            // problem with S/36 command line. Finally got it.
            if (l <= 3) return false;

            screen52.setErrorLine(bk.getNextByte()); // error row
            int byte1 = 0;

            if (l >= 5) {
                byte1 = bk.getNextByte();
                dataIncluded[23] = (byte1 & 0x80) == 0x80;
                dataIncluded[22] = (byte1 & 0x40) == 0x40;
                dataIncluded[21] = (byte1 & 0x20) == 0x20;
                dataIncluded[20] = (byte1 & 0x10) == 0x10;
                dataIncluded[19] = (byte1 & 0x8) == 0x8;
                dataIncluded[18] = (byte1 & 0x4) == 0x4;
                dataIncluded[17] = (byte1 & 0x2) == 0x2;
                dataIncluded[16] = (byte1 & 0x1) == 0x1;
            }

            if (l >= 6) {
                byte1 = bk.getNextByte();
                dataIncluded[15] = (byte1 & 0x80) == 0x80;
                dataIncluded[14] = (byte1 & 0x40) == 0x40;
                dataIncluded[13] = (byte1 & 0x20) == 0x20;
                dataIncluded[12] = (byte1 & 0x10) == 0x10;
                dataIncluded[11] = (byte1 & 0x8) == 0x8;
                dataIncluded[10] = (byte1 & 0x4) == 0x4;
                dataIncluded[9] = (byte1 & 0x2) == 0x2;
                dataIncluded[8] = (byte1 & 0x1) == 0x1;
            }

            if (l >= 7) {
                byte1 = bk.getNextByte();
                dataIncluded[7] = (byte1 & 0x80) == 0x80;
                dataIncluded[6] = (byte1 & 0x40) == 0x40;
                dataIncluded[5] = (byte1 & 0x20) == 0x20;
                dataIncluded[4] = (byte1 & 0x10) == 0x10;
                dataIncluded[3] = (byte1 & 0x8) == 0x8;
                dataIncluded[2] = (byte1 & 0x4) == 0x4;
                dataIncluded[1] = (byte1 & 0x2) == 0x2;
                dataIncluded[0] = (byte1 & 0x1) == 0x1;
            }

            return false;
        }
        else {
            sendNegResponse(NR_REQUEST_ERROR, 0x05, 0x01, 0x2B,
                            "invalid SOH length");
            return true;
        }
    }

    private void processCC0(byte byte0) {
        Log.d(TAG, " Control byte0 " + Integer.toBinaryString(byte0 & 0xff));
        boolean lockKeyboard = true;
        boolean resetMDT = false;
        boolean resetMDTAll = false;
        boolean nullMDT = false;
        boolean nullAll = false;

        // Bits 3 to 6 are reserved and should be set to '0000'
        // 0xE0 = '11100000' - only the first 3 bits are tested
        if ((byte0 & 0xE0) == 0x00) {
            lockKeyboard = false;
        }

        // '00100000' = 0x20 /32 -- just lock keyboard
        // '01000000' = 0x40 /64
        // '01100000' = 0x60 /96
        // '10000000' = 0x80 /128
        // '10100000' = 0xA0 /160
        // '11000000' = 0xC0 /192
        // '11100000' = 0xE0 /224

        switch (byte0 & 0xE0) {
            case 0x40:
                resetMDT = true;
                break;

            case 0x60:
                resetMDTAll = true;
                break;

            case 0x80:
                nullMDT = true;
                break;

            case 0xA0:
                resetMDT = true;
                nullAll = true;
                break;

            case 0xC0:
                resetMDT = true;
                nullMDT = true;
                break;

            case 0xE0:
                resetMDTAll = true;
                nullAll = true;
                break;
        }

        if (lockKeyboard) {
            screen52.getOIA().setKeyBoardLocked(true);
            pendingUnlock = false;
        }
        else
            pendingUnlock = false;

        if (resetMDT || resetMDTAll || nullMDT || nullAll) {
            ScreenField sf;
            int f = screen52.getScreenFields().getSize();

            for (int x = 0; x < f; x++) {
                sf = screen52.getScreenFields().getField(x);

                if (!sf.isBypassField()) {
                    if ((nullMDT && sf.mdt) || nullAll) {
                        sf.setFieldChar((char) 0x0);
                        screen52.drawField(sf);
                    }
                }

                if (resetMDTAll || (resetMDT && !sf.isBypassField()))
                    sf.resetMDT();
            }

            sf = null;
        }
    }

    private void processCC1(byte byte1) {
        Log.d(TAG, " Control byte1 " + Integer.toBinaryString(byte1 & 0xff));

        if ((byte1 & 0x04) == 0x04) {
            manager.playBeep();
        }

        if ((byte1 & 0x02) == 0x02) {
            screen52.getOIA().setMessageLightOff();
        }

        if ((byte1 & 0x01) == 0x01) {
            screen52.getOIA().setMessageLightOn();
        }

        if ((byte1 & 0x01) == 0x01 && (byte1 & 0x02) == 0x02) {
            screen52.getOIA().setMessageLightOn();
        }

        // reset blinking cursor seems to control whether to set or not set the
        // the cursor position. No documentation for this just testing and
        // looking at the bit settings of this field. This was a pain in the
        // ass!
        //
        // if it is off '0' then keep existing cursor positioning information
        // if it is on '1' then reset the cursor positioning information
        // *** Note *** unless we receive bit 4 on at the same time
        // this seems to work so far
        if ((byte1 & 0x20) == 0x20 && (byte1 & 0x08) == 0x00) {
            screen52.setPendingInsert(false);
            Log.d(TAG, " WTD position no move");
        }
        else {
            screen52.setPendingInsert(true);
            Log.d(TAG, " WTD position move to home" + screen52.homePos + " row "
                  + screen52.getRow(screen52.homePos) + " col "
                  + screen52.getCol(screen52.homePos));
        }

        // in enhanced mode we sometimes only receive bit 6 turned on which
        // is reset blinking cursor
        if ((byte1 & 0x20) == 0x20 && enhanced) {
            cursorOn = true;
        }

        if (!screen52.isStatusErrorCode() && (byte1 & 0x08) == 0x08) {
            //         screen52.setStatus(screen52.STATUS_SYSTEM,screen52.STATUS_VALUE_OFF,null);
            cursorOn = true;
        }

        if ((byte1 & 0x20) == 0x20 && (byte1 & 0x08) == 0x00) {
            screen52.setPendingInsert(false, 1, 1);
        }
    }

    private boolean isAttribute(int byte0) {
        int byte1 = byte0 & 0xff;
        return (byte1 & 0xe0) == 0x20;
    }

    //LDC - 12/02/2003 - Function name changed from isData to isDataEBCDIC
    private boolean isDataEBCDIC(int byte0) {
        int byte1 = byte0 & 0xff;

        // here it should always be less than 255
        if (byte1 >= 64 && byte1 < 255)
            return true;
        else
            return false;
    }

    //LDC - 12/02/2003 - Test if the unicode character is a displayable
    // character.
    //  The first 32 characters are non displayable characters
    //  This is normally the inverse of isDataEBCDIC (That's why there is a
    //  check on 255 -> 0xFFFF
    private boolean isDataUnicode(int byte0) {
        return (((byte0 < 0) || (byte0 >= 32)) && (byte0 != 0xFFFF));
    }

    private void writeStructuredField() {
        boolean done = false;

        try {
            int length = ((bk.getNextByte() & 0xff) << 8 | (bk.getNextByte() & 0xff));

            while (bk.hasNext() && !done) {
                switch (bk.getNextByte()) {
                    case -39: // SOH - Start of Header Order
                        switch (bk.getNextByte()) {
                            case 112: // 5250 Query
                                bk.getNextByte(); // get null required field
                                sendQueryResponse();
                                break;

                            default:
                                Log.d(TAG, "invalid structured field sub command "
                                      + bk.getByteOffset(-1));
                                break;
                        }

                        break;

                    default:
                        Log.d(TAG, "invalid structured field command "
                              + bk.getByteOffset(-1));
                        break;
                }
            }
        }
        catch (Exception e) {
        }

        ;
    }

    private final void writeErrorCode() throws Exception {
        screen52.setCursor(screen52.getErrorLine(), 1); // Skip the control byte
        screen52.setStatus(Screen5250.STATUS_ERROR_CODE,
                           Screen5250.STATUS_VALUE_ON, null);
        screen52.saveErrorLine();
        cursorOn = true;
    }

    private final void writeErrorCodeToWindow() throws Exception {
        int fromCol = bk.getNextByte() & 0xff; // from column
        int toCol = bk.getNextByte() & 0xff; // to column
        screen52.setCursor(screen52.getErrorLine(), fromCol); // Skip the control byte
        screen52.setStatus(Screen5250.STATUS_ERROR_CODE,
                           Screen5250.STATUS_VALUE_ON, null);
        screen52.saveErrorLine();
        cursorOn = true;
    }

    /**
     * Method sendQueryResponse
     *
     * The query command is used to obtain information about the capabilities of
     * the 5250 display.
     *
     * The Query command must follow an Escape (0x04) and Write Structured Field
     * command (0xF3).
     *
     * This section is modeled after the rfc1205 - 5250 Telnet Interface section
     * 5.3
     *
     * @throws IOException
     */
    private final void sendQueryResponse() throws IOException {
        Log.i(TAG, "sending query response");
        byte abyte0[] = new byte[64];
        abyte0[0] = 0; // Cursor Row/column (set to zero)
        abyte0[1] = 0; //           ""
        abyte0[2] = -120; // X'88' inbound write structure Field aid

        if (enhanced) {
            abyte0[3] = 0; // 0x003D (61) length of query response
            abyte0[4] = 64; //       "" see note below ?????????
        }
        else {
            abyte0[3] = 0; // 0x003A (58) length of query response
            abyte0[4] = 58; //       ""
            //  the length between 58 and 64 seems to cause
            //  different formatting codes to be sent from
            //  the host ???????????????? why ???????
            //    Well the why can be found in the manual if
            //       read a little more ;-)
        }

        abyte0[5] = -39; // command class 0xD9
        abyte0[6] = 112; // Command type query 0x70
        abyte0[7] = -128; // 0x80 Flag byte
        abyte0[8] = 6; // Controller Hardware Class
        abyte0[9] = 0; // 0x0600 - Other WSF or another 5250 Emulator
        abyte0[10] = 1; // Controller Code Level
        abyte0[11] = 1; //    Version 1 Rel 1.0
        abyte0[12] = 0; //       ""
        abyte0[13] = 0; // 13 - 28 are reserved so set to 0x00
        abyte0[14] = 0; //       ""
        abyte0[15] = 0; //       ""
        abyte0[16] = 0; //       ""
        abyte0[17] = 0; //       ""
        abyte0[18] = 0; //       ""
        abyte0[19] = 0; //       ""
        abyte0[20] = 0; //       ""
        abyte0[21] = 0; //       ""
        abyte0[22] = 0; //       ""
        abyte0[23] = 0; //       ""
        abyte0[24] = 0; //       ""
        abyte0[25] = 0; //       ""
        abyte0[26] = 0; //       ""
        abyte0[27] = 0; //       ""
        abyte0[28] = 0; //       ""
        abyte0[29] = 1; // Device type - 0x01 5250 Emulator
        abyte0[30] = codePage.uni2ebcdic('5'); // Device type character
        abyte0[31] = codePage.uni2ebcdic('2'); //          ""
        abyte0[32] = codePage.uni2ebcdic('5'); //          ""
        abyte0[33] = codePage.uni2ebcdic('1'); //          ""
        abyte0[34] = codePage.uni2ebcdic('0'); //          ""
        abyte0[35] = codePage.uni2ebcdic('1'); //          ""
        abyte0[36] = codePage.uni2ebcdic('1'); //          ""
        abyte0[37] = 2; // Keyboard Id - 0x02 Standard Keyboard
        abyte0[38] = 0; // extended keyboard id
        abyte0[39] = 0; // reserved
        abyte0[40] = 0; // 40 - 43 Display Serial Number
        abyte0[41] = 36; //
        abyte0[42] = 36; //
        abyte0[43] = 0; //
        abyte0[44] = 1; // Maximum number of display fields - 256
        abyte0[45] = 0; // 0x0100
        abyte0[46] = 0; // 46 -48 Reserved set to 0x00
        abyte0[47] = 0;
        abyte0[48] = 0;
        abyte0[49] = 1; // 49 - 53 Controller Display Capability
        abyte0[50] = 17; //      see rfc - tired of typing :-)
        abyte0[51] = 0; //          ""
        abyte0[52] = 0; //          ""

        //  53
        //    Bit 0-2: B'000' - no graphics capability
        //             B'001' - 5292-2 style graphics
        //    Bit 3-7: B '00000' = reserved (it seems for Client access)

        if (enhanced) {
            //         abyte0[53] = 0x5E; // 0x5E turns on enhanced mode
            //         abyte0[53] = 0x27; // 0x5E turns on enhanced mode
            abyte0[53] = 0x7; //  0x5E turns on ehnhanced mode
            Log.i(TAG, "enhanced options");
        }
        else
            abyte0[53] = 0x0; //  0x0 is normal emulation

        abyte0[54] = 24; // 54 - 60 Reserved set to 0x00
        //  54 - I found out is used for enhanced user
        //       interface level 3. Bit 4 allows headers
        //       and footers for windows
        abyte0[54] = 8; // 54 - 60 Reserved set to 0x00
        //  54 - I found out is used for enhanced user
        //       interface level 3. Bit 4 allows headers
        //       and footers for windows
        abyte0[55] = 0;
        abyte0[56] = 0;
        abyte0[57] = 0;
        abyte0[58] = 0;
        abyte0[59] = 0;
        abyte0[60] = 0;
        abyte0[61] = 0; // gridlines are not supported
        abyte0[62] = 0; // gridlines are not supported
        abyte0[63] = 0;
        writeGDS(0, 0, abyte0); // now tell them about us
        abyte0 = null;
    }

    protected final boolean negotiate(byte abyte0[]) throws IOException {
        int i = 0;

        // from server negotiations
        if (abyte0[i] == IAC) { // -1
            while (i < abyte0.length && abyte0[i++] == -1)

                //         while(i < abyte0.length && (abyte0[i] == -1 || abyte0[i++] == 0x20))
                switch (abyte0[i++]) {
                    // we will not worry about what it WONT do
                    case WONT:            // -4
                    default:
                        break;

                    case DO: //-3

                        // not sure why but since moving to V5R2 we are receiving a
                        //   DO with no option when connecting a second session with
                        //   device name.  Can not find the cause at all.  If anybody
                        //   is interested please debug this until then this works.
                        if (i < abyte0.length) {
                            switch (abyte0[i]) {
                                case TERMINAL_TYPE: // 24
                                    baosp.write(IAC);
                                    baosp.write(WILL);
                                    baosp.write(TERMINAL_TYPE);
                                    writeByte(baosp.toByteArray());
                                    baosp.reset();
                                    break;

                                case OPT_END_OF_RECORD: // 25
                                    baosp.write(IAC);
                                    baosp.write(WILL);
                                    baosp.write(OPT_END_OF_RECORD);
                                    writeByte(baosp.toByteArray());
                                    baosp.reset();
                                    break;

                                case TRANSMIT_BINARY: // 0
                                    baosp.write(IAC);
                                    baosp.write(WILL);
                                    baosp.write(TRANSMIT_BINARY);
                                    writeByte(baosp.toByteArray());
                                    baosp.reset();
                                    break;

                                case TIMING_MARK: // 6   rfc860
                                    //                        System.out.println("Timing Mark Received and notifying " +
                                    //                        "the server that we will not do it");
                                    baosp.write(IAC);
                                    baosp.write(WONT);
                                    baosp.write(TIMING_MARK);
                                    writeByte(baosp.toByteArray());
                                    baosp.reset();
                                    break;

                                case NEW_ENVIRONMENT: // 39 rfc1572, rfc4777
                                    // allways send new environment vars ...
                                    baosp.write(IAC);
                                    baosp.write(WILL);
                                    baosp.write(NEW_ENVIRONMENT);
                                    writeByte(baosp.toByteArray());
                                    baosp.reset();
                                    break;

                                default:  // every thing else we will not do at this time
                                    baosp.write(IAC);
                                    baosp.write(WONT);
                                    baosp.write(abyte0[i]); // either
                                    writeByte(baosp.toByteArray());
                                    baosp.reset();
                                    break;
                            }
                        }

                        i++;
                        break;

                    case WILL:
                        switch (abyte0[i]) {
                            case OPT_END_OF_RECORD: // 25
                                baosp.write(IAC);
                                baosp.write(DO);
                                baosp.write(OPT_END_OF_RECORD);
                                writeByte(baosp.toByteArray());
                                baosp.reset();
                                break;

                            case TRANSMIT_BINARY: // '\0'
                                baosp.write(IAC);
                                baosp.write(DO);
                                baosp.write(TRANSMIT_BINARY);
                                writeByte(baosp.toByteArray());
                                baosp.reset();
                                break;
                        }

                        i++;
                        break;

                    case SB: // -6
                        if (abyte0[i] == NEW_ENVIRONMENT && abyte0[i + 1] == 1) {
                            negNewEnvironment();

                            while (++i < abyte0.length && abyte0[i + 1] != IAC);
                        }

                        if (abyte0[i] == TERMINAL_TYPE && abyte0[i + 1] == 1) {
                            baosp.write(IAC);
                            baosp.write(SB);
                            baosp.write(TERMINAL_TYPE);
                            baosp.write(QUAL_IS);

                            if (!support132)
                                baosp.write("IBM-3179-2".getBytes());
                            else
                                baosp.write("IBM-3477-FC".getBytes());

                            baosp.write(IAC);
                            baosp.write(SE);
                            writeByte(baosp.toByteArray());
                            baosp.reset();
                            i++;
                        }

                        i++;
                        break;
                }

            return true;
        }
        else {
            return false;
        }
    }

    /**
     * Negotiate new environment string for device name
     *
     * @throws IOException
     */
    private void negNewEnvironment() throws IOException {
        baosp.write(IAC);
        baosp.write(SB);
        baosp.write(NEW_ENVIRONMENT);
        baosp.write(IS);

        // http://tools.ietf.org/html/rfc4777

        if (kbdTypesCodePage != null) {
            baosp.write(USERVAR);
            baosp.write("KBDTYPE".getBytes());
            baosp.write(VALUE);
            baosp.write(kbdTypesCodePage.kbdType.getBytes());
            baosp.write(USERVAR);
            baosp.write("CODEPAGE".getBytes());
            baosp.write(VALUE);
            baosp.write(kbdTypesCodePage.codepage.getBytes());
            baosp.write(USERVAR);
            baosp.write("CHARSET".getBytes());
            baosp.write(VALUE);
            baosp.write(kbdTypesCodePage.charset.getBytes());
        }

        if (devName != null) {
            baosp.write(USERVAR);
            baosp.write("DEVNAME".getBytes());
            baosp.write(VALUE);
            baosp.write(negDeviceName().getBytes());
        }

        if (user != null) {
            baosp.write(VAR);
            baosp.write("USER".getBytes());
            baosp.write(VALUE);
            baosp.write(user.getBytes());

            if (password != null) {
                baosp.write(USERVAR);
                baosp.write("IBMRSEED".getBytes());
                baosp.write(VALUE);
                baosp.write(NEGOTIATE_ESC);
                baosp.write(0x0);
                baosp.write(0x0);
                baosp.write(0x0);
                baosp.write(0x0);
                baosp.write(0x0);
                baosp.write(0x0);
                baosp.write(0x0);
                baosp.write(0x0);
                baosp.write(USERVAR);
                baosp.write("IBMSUBSPW".getBytes());
                baosp.write(VALUE);
                baosp.write(password.getBytes());
            }

            if (library != null) {
                baosp.write(USERVAR);
                baosp.write("IBMCURLIB".getBytes());
                baosp.write(VALUE);
                baosp.write(library.getBytes());
            }

            if (initialMenu != null) {
                baosp.write(USERVAR);
                baosp.write("IBMIMENU".getBytes());
                baosp.write(VALUE);
                baosp.write(initialMenu.getBytes());
            }

            if (program != null) {
                baosp.write(USERVAR);
                baosp.write("IBMPROGRAM".getBytes());
                baosp.write(VALUE);
                baosp.write(program.getBytes());
            }
        }

        baosp.write(IAC);
        baosp.write(SE);
        writeByte(baosp.toByteArray());
        baosp.reset();
    }

    /**
     * This will negotiate a device name with controller. if the sequence is
     * less than zero then it will send the device name as specified. On each
     * unsuccessful attempt a sequential number is appended until we find one or
     * the controller says no way.
     *
     * @return String
     */
    private String negDeviceName() {
        if (devSeq++ == -1) {
            devNameUsed = devName;
            return devName;
        }
        else {
            StringBuffer sb = new StringBuffer(devName + devSeq);
            int ei = 1;

            while (sb.length() > 10) {
                sb.setLength(0);
                sb.append(devName.substring(0, devName.length() - ei++));
                sb.append(devSeq);
            }

            devNameUsed = sb.toString();
            return devNameUsed;
        }
    }

    public final void setCodePage(String cp) {
        codePage = CharMappings.getCodePage(cp);
        cp = cp.toLowerCase();

        for (KbdTypesCodePages kbdtyp : KbdTypesCodePages.values()) {
            if (("cp" + kbdtyp.codepage).equals(cp) || kbdtyp.ccsid.equals(cp)) {
                kbdTypesCodePage = kbdtyp;
                break;
            }
        }

        Log.i(TAG, "Chose keyboard mapping " + kbdTypesCodePage.toString() + " for code page " + cp);
    }

    public final ICodePage getCodePage() {
        return codePage;
    }

    public void signalBell() {
        manager.playBeep();
    }

}