/* Copyright (C) 2002-2005 RealVNC Ltd.  All Rights Reserved.
 * Copyright (C) 2011-2019 Brian P. Hinz
 * Copyright (C) 2017 Pierre Ossman for Cendio AB
 *
 * This 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 of the License, or
 * (at your option) any later version.
 *
 * This software 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; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
 * USA.
 */

//
// CMsgReader - class for reading RFB messages on the client side
// (i.e. messages from server to client).
//

package com.tigervnc.rfb;

import java.awt.image.*;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.Charset;

import com.tigervnc.rdr.*;

public class CMsgReader {

  static LogWriter vlog = new LogWriter("CMsgReader");

  protected CMsgReader(CMsgHandler handler_, InStream is_)
  {
    imageBufIdealSize = 0;
    handler = handler_;
    is = is_;
    nUpdateRectsLeft = 0;
    imageBuf = null;
    imageBufSize = 0;
  }

  public void readServerInit()
  {
    int width = is.readU16();
    int height = is.readU16();
    PixelFormat pf = new PixelFormat();
    pf.read(is);
    String name = is.readString();
    handler.serverInit(width, height, pf, name);
  }

  public void readMsg()
  {
    if (nUpdateRectsLeft == 0) {
      int type = is.readU8();

      switch (type) {
      case MsgTypes.msgTypeSetColourMapEntries:
        readSetColourMapEntries();
        break;
      case MsgTypes.msgTypeBell:
        readBell();
        break;
      case MsgTypes.msgTypeServerCutText:
        readServerCutText();
        break;
      case MsgTypes.msgTypeFramebufferUpdate:
        readFramebufferUpdate();
        break;
      case MsgTypes.msgTypeServerFence:
        readFence();
        break;
      case MsgTypes.msgTypeEndOfContinuousUpdates:
        readEndOfContinuousUpdates();
        break;
      default:
        vlog.error("unknown message type "+type);
        throw new Exception("unknown message type");
      }
    } else {
      int x = is.readU16();
      int y = is.readU16();
      int w = is.readU16();
      int h = is.readU16();
      int encoding = is.readS32();

      switch (encoding) {
      case Encodings.pseudoEncodingLastRect:
        nUpdateRectsLeft = 1;     // this rectangle is the last one
        break;
      case Encodings.pseudoEncodingXCursor:
        readSetXCursor(w, h, new Point(x,y));
        break;
      case Encodings.pseudoEncodingCursor:
        readSetCursor(w, h, new Point(x,y));
        break;
      case Encodings.pseudoEncodingCursorWithAlpha:
        readSetCursorWithAlpha(w, h, new Point(x,y));
        break;
      case Encodings.pseudoEncodingVMwareCursor:
        readSetVMwareCursor(w, h, new Point(x,y));
        break;
      case Encodings.pseudoEncodingDesktopName:
        readSetDesktopName(x, y, w, h);
        break;
      case Encodings.pseudoEncodingDesktopSize:
        handler.setDesktopSize(w, h);
        break;
      case Encodings.pseudoEncodingExtendedDesktopSize:
        readExtendedDesktopSize(x, y, w, h);
        break;
      case Encodings.pseudoEncodingClientRedirect:
        nUpdateRectsLeft = 0;
        readClientRedirect(x, y, w, h);
        return;
      default:
        readRect(new Rect(x, y, x+w, y+h), encoding);
        break;
      };

      nUpdateRectsLeft--;
      if (nUpdateRectsLeft == 0)
        handler.framebufferUpdateEnd();
    }
  }

  protected void readSetColourMapEntries()
  {
    is.skip(1);
    int firstColour = is.readU16();
    int nColours = is.readU16();
    int[] rgbs = new int[nColours * 3];
    for (int i = 0; i < nColours * 3; i++)
      rgbs[i] = is.readU16();
    handler.setColourMapEntries(firstColour, nColours, rgbs);
  }

  protected void readBell()
  {
    handler.bell();
  }

  protected void readServerCutText()
  {
    is.skip(3);
    int len = is.readU32();

    if (len > 256*1024) {
      is.skip(len);
      vlog.error("cut text too long ("+len+" bytes) - ignoring");
      return;
    }

    ByteBuffer buf = ByteBuffer.allocate(len);
    is.readBytes(buf, len);
    Charset latin1 = Charset.forName("ISO-8859-1");
    CharBuffer chars = latin1.decode(buf.compact());
    handler.serverCutText(chars.toString(), len);
  }

  protected void readFence()
  {
    int flags;
    int len;
    ByteBuffer data = ByteBuffer.allocate(64);

    is.skip(3);

    flags = is.readU32();

    len = is.readU8();
    if (len > data.capacity()) {
      System.out.println("Ignoring fence with too large payload\n");
      is.skip(len);
      return;
    }

    is.readBytes(data, len);

    handler.fence(flags, len, data.array());
  }

  protected void readEndOfContinuousUpdates()
  {
    handler.endOfContinuousUpdates();
  }

  protected void readFramebufferUpdate()
  {
    is.skip(1);
    nUpdateRectsLeft = is.readU16();
    handler.framebufferUpdateStart();
  }

  protected void readRect(Rect r, int encoding)
  {
    if ((r.br.x > handler.server.width()) || (r.br.y > handler.server.height())) {
      vlog.error("Rect too big: "+r.width()+"x"+r.height()+" at "+
                  r.tl.x+","+r.tl.y+" exceeds "+handler.server.width()+"x"+
                  handler.server.height());
      throw new Exception("Rect too big");
    }

    if (r.is_empty())
      vlog.error("Ignoring zero size rect");

    handler.dataRect(r, encoding);
  }

  protected void readSetXCursor(int width, int height, Point hotspot)
  {
    byte pr, pg, pb;
    byte sr, sg, sb;
    int data_len = ((width+7)/8) * height;
    int mask_len = ((width+7)/8) * height;
    ByteBuffer data = ByteBuffer.allocate(data_len);
    ByteBuffer mask = ByteBuffer.allocate(mask_len);

    int x, y;
    byte[] buf = new byte[width*height*4];
    ByteBuffer out;

    if (width * height == 0)
      return;

    pr = (byte)is.readU8();
    pg = (byte)is.readU8();
    pb = (byte)is.readU8();

    sr = (byte)is.readU8();
    sg = (byte)is.readU8();
    sb = (byte)is.readU8();

    is.readBytes(data, data_len);
    is.readBytes(mask, mask_len);

    int maskBytesPerRow = (width+7)/8;
    out = ByteBuffer.wrap(buf);
    for (y = 0;y < height;y++) {
      for (x = 0;x < width;x++) {
        int byte_ = y * maskBytesPerRow + x / 8;
        int bit = 7 - x % 8;

        // NOTE: BufferedImage needs ARGB, rather than RGBA
        if ((mask.get(byte_) & (1 << bit)) > 0)
          out.put(out.position(), (byte)255);
        else
          out.put(out.position(), (byte)0);

        if ((data.get(byte_) & (1 << bit)) > 0) {
          out.put(out.position() + 1, pr);
          out.put(out.position() + 2, pg);
          out.put(out.position() + 3, pb);
        } else {
          out.put(out.position() + 1, sr);
          out.put(out.position() + 2, sg);
          out.put(out.position() + 3, sb);
        }

        out.position(out.position() + 4);
      }
    }

    handler.setCursor(width, height, hotspot, buf);
  }

  protected void readSetCursor(int width, int height, Point hotspot)
  {
    int data_len = width * height * (handler.server.pf().bpp/8);
    int mask_len = ((width+7)/8) * height;
    ByteBuffer data = ByteBuffer.allocate(data_len);
    ByteBuffer mask = ByteBuffer.allocate(mask_len);

    int x, y;
    byte[] buf = new byte[width*height*4];
    ByteBuffer in;
    ByteBuffer out;

    is.readBytes(data, data_len);
    is.readBytes(mask, mask_len);

    int maskBytesPerRow = (width+7)/8;
    in = ByteBuffer.wrap(data.array());
    out = ByteBuffer.wrap(buf);
    for (y = 0;y < height;y++) {
      for (x = 0;x < width;x++) {
        int byte_ = y * maskBytesPerRow + x / 8;
        int bit = 7 - x % 8;

        // NOTE: BufferedImage needs ARGB, rather than RGBA
        if ((mask.get(byte_) & (1 << bit)) != 0)
          out.put((byte)255);
        else
          out.put((byte)0);

        handler.server.pf().rgbFromBuffer(out.duplicate(), in.duplicate(), 1);

        in.position(in.position() + handler.server.pf().bpp/8);
        out.position(out.position() + 3);
      }
    }

    handler.setCursor(width, height, hotspot, buf);
  }

  protected void readSetCursorWithAlpha(int width, int height, Point hotspot)
  {
    int encoding;

    PixelFormat rgbaPF =
      new PixelFormat(32, 32, false, true, 255, 255, 255, 16, 8, 0);
    ManagedPixelBuffer pb =
      new ManagedPixelBuffer(rgbaPF, width, height);
    PixelFormat origPF;

    ByteBuffer buf =
      ByteBuffer.allocate(pb.area()*4).order(rgbaPF.getByteOrder());;

    encoding = is.readS32();

    origPF = handler.server.pf();
    handler.server.setPF(rgbaPF);
    handler.readAndDecodeRect(pb.getRect(), encoding, pb);
    handler.server.setPF(origPF);

    // ARGB with pre-multiplied alpha works best for BufferedImage
    if (pb.area() > 0) {
      // Sometimes a zero width or height cursor is sent.
      DataBuffer db = pb.getBuffer(pb.getRect()).getDataBuffer();
      for (int i = 0;i < pb.area();i++)
        buf.asIntBuffer().put(i, db.getElem(i));
    }

    for (int i = 0;i < pb.area();i++) {
      byte alpha = buf.get(buf.position()+3);

      buf.put(i*4+3, buf.get(i*4+2));
      buf.put(i*4+2, buf.get(i*4+1));
      buf.put(i*4+1, buf.get(i*4+0));
      buf.put(i*4+0, alpha);

      buf.position(buf.position() + 4);
    }

    handler.setCursor(width, height, hotspot, buf.array());
  }

  protected void readSetVMwareCursor(int width, int height, Point hotspot)
  {
    // VMware cursor sends RGBA, java BufferedImage needs ARGB
    if (width > maxCursorSize || height > maxCursorSize)
      throw new Exception("Too big cursor");

    byte type;

    type = (byte)is.readU8();
    is.skip(1);

    if (type == 0) {
      int len = width * height * (handler.server.pf().bpp/8);
      ByteBuffer andMask = ByteBuffer.allocate(len);
      ByteBuffer xorMask = ByteBuffer.allocate(len);

      ByteBuffer data = ByteBuffer.allocate(width*height*4);

      ByteBuffer andIn;
      ByteBuffer xorIn;
      ByteBuffer out;
      int Bpp;

      is.readBytes(andMask, len);
      is.readBytes(xorMask, len);

      andIn = ByteBuffer.wrap(andMask.array());
      xorIn = ByteBuffer.wrap(xorMask.array());
      out = ByteBuffer.wrap(data.array());
      Bpp = handler.server.pf().bpp/8;
      for (int y = 0;y < height;y++) {
        for (int x = 0;x < width;x++) {
          int andPixel, xorPixel;

          andPixel = handler.server.pf().pixelFromBuffer(andIn.duplicate());
          xorPixel = handler.server.pf().pixelFromBuffer(xorIn.duplicate());
          andIn.position(andIn.position() + Bpp);
          xorIn.position(xorIn.position() + Bpp);

          if (andPixel == 0) {
            byte r, g, b;

            // Opaque pixel

            r = (byte)handler.server.pf().getColorModel().getRed(xorPixel);
            g = (byte)handler.server.pf().getColorModel().getGreen(xorPixel);
            b = (byte)handler.server.pf().getColorModel().getBlue(xorPixel);
            out.put((byte)0xff);
            out.put(r);
            out.put(g);
            out.put(b);
          } else if (xorPixel == 0) {
            // Fully transparent pixel
            out.put((byte)0);
            out.put((byte)0);
            out.put((byte)0);
            out.put((byte)0);
          } else if (andPixel == xorPixel) {
            // Inverted pixel

            // We don't really support this, so just turn the pixel black
            // FIXME: Do an outline like WinVNC does?
            out.put((byte)0xff);
            out.put((byte)0);
            out.put((byte)0);
            out.put((byte)0);
          } else {
            // Partially transparent/inverted pixel

            // We _really_ can't handle this, just make it black
            out.put((byte)0xff);
            out.put((byte)0);
            out.put((byte)0);
            out.put((byte)0);
          }
        }
      }

      handler.setCursor(width, height, hotspot, data.array());
    } else if (type == 1) {
      ByteBuffer data = ByteBuffer.allocate(width*height*4);

      // FIXME: Is alpha premultiplied?
      ByteBuffer buf = ByteBuffer.allocate(4);
      for (int i=0;i < width*height*4;i+=4) {
        is.readBytes(buf,4);
        data.put(buf.array(),3,1);
        data.put(buf.array(),0,3);
        buf.clear();
      }

      handler.setCursor(width, height, hotspot, data.array());
    } else {
      throw new Exception("Unknown cursor type");
    }
  }

  protected void readSetDesktopName(int x, int y, int w, int h)
  {
    String name = is.readString();

    if (x != 0 || y != 0 || w != 0 || h != 0) {
      vlog.error("Ignoring DesktopName rect with non-zero position/size");
    } else {
      handler.setName(name);
    }

  }

  protected void readExtendedDesktopSize(int x, int y, int w, int h)
  {
    int screens, i;
    int id, flags;
    int sx, sy, sw, sh;
    ScreenSet layout = new ScreenSet();

    screens = is.readU8();
    is.skip(3);

    for (i = 0;i < screens;i++) {
      id = is.readU32();
      sx = is.readU16();
      sy = is.readU16();
      sw = is.readU16();
      sh = is.readU16();
      flags = is.readU32();

      layout.add_screen(new Screen(id, sx, sy, sw, sh, flags));
    }

    handler.setExtendedDesktopSize(x, y, w, h, layout);
  }

  protected void readClientRedirect(int x, int y, int w, int h)
  {
    int port = is.readU16();
    String host = is.readString();
    String x509subject = is.readString();

    if (x != 0 || y != 0 || w != 0 || h != 0)
      vlog.error("Ignoring ClientRedirect rect with non-zero position/size");
    else
      handler.clientRedirect(port, host, x509subject);
  }

  public int[] getImageBuf(int required) { return getImageBuf(required, 0, 0); }

  public int[] getImageBuf(int required, int requested, int nPixels)
  {
    int requiredBytes = required;
    int requestedBytes = requested;
    int size = requestedBytes;
    if (size > imageBufIdealSize) size = imageBufIdealSize;

    if (size < requiredBytes)
      size = requiredBytes;

    if (imageBufSize < size) {
      imageBufSize = size;
      imageBuf = new int[imageBufSize];
    }
    if (nPixels != 0)
      nPixels = imageBufSize / (handler.server.pf().bpp / 8);
    return imageBuf;
  }

  public InStream getInStream() { return is; }

  public int imageBufIdealSize;

  protected CMsgHandler handler;
  protected InStream is;
  protected int nUpdateRectsLeft;
  protected final int maxCursorSize = 256;
  protected int[] imageBuf;
  protected int imageBufSize;
}