package org.tn5250j.framework.tn5250;

import org.tn5250j.encoding.ICodePage;

import java.io.BufferedInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.net.SocketException;
import java.util.concurrent.BlockingQueue;

import static org.tn5250j.framework.tn5250.Stream5250.OPCODE_OFFSET;

import java.util.Timer;
import java.util.TimerTask;

import android.util.Log;


public class DataStreamProducer implements Runnable {
    private static final int MINIMAL_PARTIAL_STREAM_LEN = 2;
    private static final String TAG = "DataStreamProducer";
    private tnvt                vt;
    private BufferedInputStream bin;
    private ByteArrayOutputStream baosin;
    private byte[] saveStream;
    private final BlockingQueue<Object> dsq;
    private byte[] dataStream;
    private DataStreamDumper dataStreamDumper = new DataStreamDumper();



    public DataStreamProducer(tnvt vt, BufferedInputStream bin, BlockingQueue<Object> queue, byte[] init) {
        this.bin    = bin;
        this.vt     = vt;
        baosin = new ByteArrayOutputStream();
        dsq = queue;
        dataStream = init;
    }

    public final void run() {
        boolean done = false;
        Thread me = Thread.currentThread();
        // load the first response screen
        loadStream(dataStream, 0);

        while (!done) {
            try {
                byte[] abyte0 = readIncoming();

                // WVL - LDC : 17/05/2004 : Device name negotiations send TIMING MARK
                // Restructured to the readIncoming() method to return null
                // on TIMING MARK. Don't process in that case (abyte0 == null)!
                if (abyte0 != null) {
                    // WVL - LDC : 16/07/2003 : TR.000345
                    // When the socket has been closed, the reading returns
                    // no bytes (an empty byte arrray).
                    // But the loadStream fails on this, so we check it here!
                    if (abyte0.length > 0) {
                        loadStream(abyte0, 0);
                    }
                    // WVL - LDC : 16/07/2003 : TR.000345
                    // Returning no bytes means the input buffer has
                    // reached end-of-stream, so we do a disconnect!
                    else {
                        done = true;
                        vt.disconnect();
                    }
                }
            }
            catch (SocketException se) {
                Log.w(TAG, "   DataStreamProducer thread interrupted and stopping " + se.getMessage());
                done = true;
            }
            catch (IOException ioe) {
                Log.w(TAG, ioe.getMessage());
                if (me.isInterrupted()) done = true;
            }
            catch (Exception ex) {
                Log.w(TAG, ex.getMessage());
                if (me.isInterrupted()) done = true;
            }
        }
    }

    private void loadStream(byte streamBuffer[], int offset) {

        int partialLen = (streamBuffer[offset] & 0xff) << 8 | streamBuffer[offset + 1] & 0xff;
        int bufferLen = streamBuffer.length;

        Log.d(TAG, "loadStream() offset=" + offset + " partialLen=" + partialLen + " bufferLen=" + bufferLen);

        if (saveStream != null) {
            Log.d(TAG, "partial stream found");
            bufferLen = saveStream.length + streamBuffer.length;
            byte[] inter = new byte[bufferLen];
            System.arraycopy(saveStream, 0, inter, 0, saveStream.length);
            System.arraycopy(streamBuffer, 0, inter, saveStream.length, streamBuffer.length);
            streamBuffer = new byte[bufferLen];
            System.arraycopy(inter, 0, streamBuffer, 0, bufferLen);
            saveStream = null;
        }

        if (partialLen > bufferLen) {
          saveStream = new byte[streamBuffer.length];
          Log.d(TAG, "partial stream saved");
          System.arraycopy(streamBuffer, 0, saveStream, 0, streamBuffer.length);
        } else {
            int buf_len = partialLen + 2;
            byte[] buf = new byte[buf_len];
            if (isBufferShifted(partialLen, bufferLen) && isOpcodeShifted(streamBuffer, offset)) {
                Log.d(TAG, "Invalid stream buffer detected. Ignoring the inserted byte.");
                System.arraycopy(streamBuffer, offset, buf, 0, MINIMAL_PARTIAL_STREAM_LEN);
                System.arraycopy(streamBuffer, offset + MINIMAL_PARTIAL_STREAM_LEN + 1, buf, MINIMAL_PARTIAL_STREAM_LEN, partialLen);
            } else {
                System.arraycopy(streamBuffer, offset, buf, 0, buf_len);
            }
            try {
                dsq.put(buf);
                if (streamBuffer.length > buf.length + offset + MINIMAL_PARTIAL_STREAM_LEN)
                    loadStream(streamBuffer, offset + buf_len);
            } catch (InterruptedException ex) {
                Log.w(TAG, "load stream error.", ex);
            }
        }
    }

    private boolean isOpcodeShifted(byte[] streamBuffer, int offset) {
        byte code = streamBuffer[offset + 1 + OPCODE_OFFSET];
        return (0 <= code && code <= 12);
    }

    private boolean isBufferShifted(int partialLen, int bufferLen) {
        return partialLen + MINIMAL_PARTIAL_STREAM_LEN + 1 == bufferLen;
    }

    public final byte[] readIncoming() throws IOException {
        boolean done = false;
        boolean negotiate = false;
        baosin.reset();
        int j = -1;
        Timer timer = new Timer("data.stream", true);
        TimerTask task = null;

        while (!done) {
            if (bin.available() == 0) {
                task = new TimerTask() {
                    public void run() {
                        try {
                            dsq.put(new Integer(0));  // trigger buffer.testChanged()
                        }
                        catch (Exception ex) {
                            Log.w(TAG, "readIncoming error " + ex.getMessage());
                        }
                    }
                };
                timer.schedule(task, 10);   // 10 ms delay
            }

            int i = bin.read();

            if (task != null) {
                task.cancel();
                task = null;
            }

            // WVL - LDC : 16/07/2003 : TR.000345
            // The inStream return -1 when end-of-stream is reached. This
            // happens e.g. when the connection is closed from the AS/400.
            // So we stop in this case!
            // ==> an empty byte array is returned from this method.
            if (i == -1) { // nothing read!
                done = true;
                vt.disconnect();
                continue;
            }

            // We use the values instead of the static values IAC and EOR
            //    because they are defined as bytes.
            //
            // The > if(i != 255 || j != 255)  < is a hack for the double FF FF's
            // that are being returned.  I do not know why this is like this and
            // can not find any documentation for it.  It is also being returned
            // on my Client Access tcp dump as well so they are handling it.
            //
            // my5250
            // 0000:  00 50 DA 44 C8 45 42 00 00 00 00 24 08 00 45 00 .P.D.EB....$..E.
            // 0010:  04 2A BC F9 00 00 40 06 D0 27 C1 A8 33 04 C1 A8 .*....@..'..3...
            // 0020:  33 58 00 17 04 18 6F A2 83 CB 00 1E D1 BA 50 18 3X....o.......P.
            // 0030:  20 00 8A 9A 00 00 03 FF FF 12 A0 00 00 04 00 00  ...............
            // --------------------------- || || -------------------------------------
            // 0040:  03 04 40 04 11 00 20 01 07 00 00 00 18 00 00 10 ..@... .........

            if (j == 255 && i == 255) {
                j = -1;
                continue;
            }

            baosin.write(i);

            // check for end of record EOR and IAC  - FFEF
            if (j == 255 && i == 239)
                done = true;

            // This is to check for the TELNET TIMING MARK OPTION
            // rfc860 explains this in more detail.  When we receive it
            // we will negotiate with the server by sending a WONT'T TIMING-MARK
            // This will let the server know that we processed the information
            // and are just waiting for the user to enter some data so keep the
            // socket alive.   This is more or less a AYT (ARE YOU THERE) or not.
            if (i == 253 && j == 255) {
                done = true;
                negotiate = true;
            }

            j = i;
        }

        // after the initial negotiation we might get other options such as
        //    timing marks ??????????????  do we ???????????? look at telnet spec
        // yes we do. rfc860 explains about timing marks.
        // WVL - LDC : 17/05/2004 : Device name negotiations send TIMING MARK
        //                          to existing device!
        // Handled incorrectly: we cannot continue processing the TIMING MARK DO
        // after we have handled it in the vt.negotiate()
        // We should not return the bytes;
        // ==> restructured to return null after negotiation!
        //     Impacts the run method! Added the null check.
        byte[] rBytes = baosin.toByteArray();

        dataStreamDumper.dump(rBytes);

        if (negotiate) {
            if (bin.available() == 0) {
                task = new TimerTask() {
                    public void run() {
                        try {
                            dsq.put(new Integer(0));  // trigger buffer.testChanged()
                        }
                        catch (Exception ex) {
                            Log.w(TAG, "readIncoming error " + ex.getMessage());
                        }
                    }
                };
                timer.schedule(task, 10);   // 10 ms delay
            }

            // get the negotiation option
            baosin.write(bin.read());

            if (task != null) {
                task.cancel();
                task = null;
            }

            vt.negotiate(rBytes);
            return null;
        }

        return rBytes;
    }

    protected void toggleDebug(ICodePage codePage) {
        dataStreamDumper.toggleDebug(codePage);
    }

}