/* Copyright (C) 2002-2004 RealVNC Ltd.  All Rights Reserved.
 *    
 * 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
 * USA.
 */
//
// TXImage.cxx
//


#include <stdio.h>
#include <strings.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <list>
#include <rfb/TransImageGetter.h>
#include <rfb/Exception.h>
#include <rfb/LogWriter.h>
#include "TXWindow.h"
#include "TXImage.h"

using namespace rfb;

static rfb::LogWriter vlog("TXImage");

TXImage::TXImage(Display* d, int width, int height, Visual* vis_, int depth_)
  : xim(0), dpy(d), vis(vis_), depth(depth_), shminfo(0), tig(0), cube(0)
{
  width_ = width;
  height_ = height;
  for (int i = 0; i < 256; i++)
    colourMap[i].r = colourMap[i].g = colourMap[i].b = 0;

  if (!vis)
    vis = DefaultVisual(dpy,DefaultScreen(dpy));
  if (!depth)
    depth = DefaultDepth(dpy,DefaultScreen(dpy));

  createXImage();
  getNativePixelFormat(vis, depth);
  colourmap = this;
  format.bpp = 0;  // just make it different to any valid format, so that...
  setPF(nativePF); // ...setPF() always works
}

TXImage::~TXImage()
{
  if (data != (rdr::U8*)xim->data) delete [] data;
  destroyXImage();
  delete tig;
  delete cube;
}

void TXImage::resize(int w, int h)
{
  if (w == width() && h == height()) return;

  int oldStrideBytes = getStride() * (format.bpp/8);
  int rowsToCopy = min(h, height());
  int bytesPerRow = min(w, width()) * (format.bpp/8);
  rdr::U8* oldData = 0;
  bool allocData = false;

  if (data != (rdr::U8*)xim->data) {
    oldData = (rdr::U8*)data;
    allocData = true;
  } else {
    oldData = new rdr::U8[xim->bytes_per_line * height()];
    memcpy(oldData, xim->data, xim->bytes_per_line * height());
  }

  destroyXImage();
  width_ = w;
  height_ = h;
  createXImage();

  if (allocData)
    data = new rdr::U8[width() * height() * (format.bpp/8)];
  else
    data = (rdr::U8*)xim->data;

  int newStrideBytes = getStride() * (format.bpp/8);
  for (int i = 0; i < rowsToCopy; i++)
    memcpy((rdr::U8*)data + newStrideBytes * i, oldData + oldStrideBytes * i,
           bytesPerRow);
  delete [] oldData;
}

void TXImage::setPF(const PixelFormat& newPF)
{
  if (newPF.equal(format)) return;
  format = newPF;

  if (data != (rdr::U8*)xim->data) delete [] data;
  delete tig;
  tig = 0;

  if (format.equal(nativePF) && format.trueColour) {
    data = (rdr::U8*)xim->data;
  } else {
    data = new rdr::U8[width() * height() * (format.bpp/8)];
    tig = new TransImageGetter();
    tig->init(this, nativePF, 0, cube);
  }
}

int TXImage::getStride() const
{
  if (data == (rdr::U8*)xim->data)
    return xim->bytes_per_line / (xim->bits_per_pixel / 8);
  else
    return width();
}

void TXImage::put(Window win, GC gc, const rfb::Rect& r)
{
  if (r.is_empty()) return;
  int x = r.tl.x;
  int y = r.tl.y;
  int w = r.width();
  int h = r.height();
  if (data != (rdr::U8*)xim->data) {
    rdr::U8* ximDataStart = ((rdr::U8*)xim->data + y * xim->bytes_per_line
                             + x * (xim->bits_per_pixel / 8));
    tig->getImage(ximDataStart, r,
                  xim->bytes_per_line / (xim->bits_per_pixel / 8));
  }
  if (usingShm()) {
    XShmPutImage(dpy, win, gc, xim, x, y, x, y, w, h, False);
  } else {
    XPutImage(dpy, win, gc, xim, x, y, x, y, w, h);
  }
}

void TXImage::setColourMapEntries(int firstColour, int nColours, rdr::U16* rgbs)
{
  for (int i = 0; i < nColours; i++) {
    colourMap[firstColour+i].r = rgbs[i*3];
    colourMap[firstColour+i].g = rgbs[i*3+1];
    colourMap[firstColour+i].b = rgbs[i*3+2];
  }
}

void TXImage::updateColourMap()
{
  tig->setColourMapEntries(0, 0, 0);
}

void TXImage::lookup(int index, int* r, int* g, int* b)
{
  *r = colourMap[index].r;
  *g = colourMap[index].g;
  *b = colourMap[index].b;
}


static bool caughtError = false;

static int XShmAttachErrorHandler(Display *dpy, XErrorEvent *error)
{
  caughtError = true;
  return 0;
}

class TXImageCleanup {
public:
  std::list<TXImage*> images;
  ~TXImageCleanup() {
    while (!images.empty())
      delete images.front();
  }
};

static TXImageCleanup imageCleanup;

void TXImage::createXImage()
{
  if (XShmQueryExtension(dpy)) {
    shminfo = new XShmSegmentInfo;

    xim = XShmCreateImage(dpy, vis, depth, ZPixmap,
                          0, shminfo, width(), height());

    if (xim) {
      shminfo->shmid = shmget(IPC_PRIVATE,
                              xim->bytes_per_line * xim->height,
                              IPC_CREAT|0777);

      if (shminfo->shmid != -1) {
        shminfo->shmaddr = xim->data = (char*)shmat(shminfo->shmid, 0, 0);

        if (shminfo->shmaddr != (char *)-1) {

          shminfo->readOnly = False;

          XErrorHandler oldHdlr = XSetErrorHandler(XShmAttachErrorHandler);
          XShmAttach(dpy, shminfo);
          XSync(dpy, False);
          XSetErrorHandler(oldHdlr);

          if (!caughtError) {
            vlog.debug("Using shared memory XImage");
            imageCleanup.images.push_back(this);
            return;
          }

          shmdt(shminfo->shmaddr);
        } else {
          vlog.error("shmat failed");
          perror("shmat");
        }

        shmctl(shminfo->shmid, IPC_RMID, 0);
      } else {
        vlog.error("shmget failed");
        perror("shmget");
      }

      XDestroyImage(xim);
      xim = 0;
    } else {
      vlog.error("XShmCreateImage failed");
    }

    delete shminfo;
    shminfo = 0;
  }

  xim = XCreateImage(dpy, vis, depth, ZPixmap,
                     0, 0, width(), height(), BitmapPad(dpy), 0);

  xim->data = (char*)malloc(xim->bytes_per_line * xim->height);
  if (!xim->data) {
    vlog.error("malloc failed");
    exit(1);
  }
}

void TXImage::destroyXImage()
{
  if (shminfo) {
    vlog.debug("Freeing shared memory XImage");
    shmdt(shminfo->shmaddr);
    shmctl(shminfo->shmid, IPC_RMID, 0);
    delete shminfo;
    shminfo = 0;
    imageCleanup.images.remove(this);
  }
  // XDestroyImage() will free(xim->data) if appropriate
  if (xim) XDestroyImage(xim);
  xim = 0;
}


static bool supportedBPP(int bpp) {
  return (bpp == 8 || bpp == 16 || bpp == 32);
}

static int depth2bpp(Display* dpy, int depth)
{
  int nformats;
  XPixmapFormatValues* format = XListPixmapFormats(dpy, &nformats);

  int i;
  for (i = 0; i < nformats; i++)
    if (format[i].depth == depth) break;

  if (i == nformats || !supportedBPP(format[i].bits_per_pixel))
    throw rfb::Exception("Error: couldn't find suitable pixmap format");

  int bpp = format[i].bits_per_pixel;
  XFree(format);
  return bpp;
}

void TXImage::getNativePixelFormat(Visual* vis, int depth)
{
  cube = 0;
  nativePF.depth = depth;
  nativePF.bpp = depth2bpp(dpy, depth);
  nativePF.bigEndian = (ImageByteOrder(dpy) == MSBFirst);
  nativePF.trueColour = (vis->c_class == TrueColor);

  vlog.info("Using default colormap and visual, %sdepth %d.",
            (vis->c_class == TrueColor) ? "TrueColor, " :
            ((vis->c_class == PseudoColor) ? "PseudoColor, " : ""),
            depth);

  if (nativePF.trueColour) {

    nativePF.redShift   = ffs(vis->red_mask)   - 1;
    nativePF.greenShift = ffs(vis->green_mask) - 1;
    nativePF.blueShift  = ffs(vis->blue_mask)  - 1;
    nativePF.redMax   = vis->red_mask   >> nativePF.redShift;
    nativePF.greenMax = vis->green_mask >> nativePF.greenShift;
    nativePF.blueMax  = vis->blue_mask  >> nativePF.blueShift;

  } else {

    XColor xc[256];
    cube = new rfb::ColourCube(6,6,6);
    int r;
    for (r = 0; r < cube->nRed; r++) {
      for (int g = 0; g < cube->nGreen; g++) {
        for (int b = 0; b < cube->nBlue; b++) {
          int i = (r * cube->nGreen + g) * cube->nBlue + b;
          xc[i].red =   r * 65535 / (cube->nRed-1);
          xc[i].green = g * 65535 / (cube->nGreen-1);
          xc[i].blue =  b * 65535 / (cube->nBlue-1);
        }
      }
    }

    TXWindow::getColours(dpy, xc, cube->size());

    for (r = 0; r < cube->nRed; r++) {
      for (int g = 0; g < cube->nGreen; g++) {
        for (int b = 0; b < cube->nBlue; b++) {
          int i = (r * cube->nGreen + g) * cube->nBlue + b;
          cube->set(r, g, b, xc[i].pixel);
        }
      }
    }
  }
}