//-----------------------------------------------------------------------------
// Torque Game Engine
// Copyright (C) GarageGames.com, Inc.
//-----------------------------------------------------------------------------

#include "core/stream.h"
#include "core/fileStream.h"
#include "core/memstream.h"
#include "dgl/gPalette.h"
#include "dgl/gBitmap.h"

#include "gif_lib.h"



//-------------------------------------- Replacement I/O for standard LIBjpeg
//                                        functions.  we don't wanna use
//                                        FILE*'s...
static int gifReadDataFn(GifFileType *gifinfo, GifByteType *data, int length)
{
   Stream *stream = (Stream*)gifinfo->UserData;
   AssertFatal(stream != NULL, "jpegReadDataFn::No stream.");
   int pos = stream->getPosition();
   if (stream->read(length, data))
      return length;

   if (stream->getStatus() == Stream::EOS)
      return (stream->getPosition()-pos);
   else
      return 0;
}


//--------------------------------------
static int gifWriteDataFn(GifFileType *gifinfo, GifByteType *data, int length)
{
   Stream *stream = (Stream*)gifinfo->UserData;
   AssertFatal(stream != NULL, "jpegWriteDataFn::No stream.");
   if (stream->write(length, data))
      return length;
   else
      return 0;
}


//--------------------------------------
bool GBitmap::readGIF(Stream &stream)
{
   GifFileType *gifinfo = DGifOpen( (void*)&stream, gifReadDataFn);
   if (!gifinfo)
      return false;

   GifRecordType recordType;
   do
   {
      if (DGifGetRecordType(gifinfo, &recordType) == GIF_ERROR)
         break;

      if (recordType == IMAGE_DESC_RECORD_TYPE)
      {
         if (DGifGetImageDesc(gifinfo) == GIF_ERROR)
            break;

         BitmapFormat format = (gifinfo->SBackGroundColor == 0 ) ? RGB : RGBA;
         allocateBitmap(gifinfo->SWidth, gifinfo->SHeight, false, format);

         U32 gwidth = gifinfo->Image.Width ? gifinfo->Image.Width : width;
         U32 gheight= gifinfo->Image.Height ? gifinfo->Image.Height : height;
         U32 gifSize = gwidth * gheight;
         U8  *data   = new U8[gifSize];

         if (DGifGetLine(gifinfo, data, gifSize) != GIF_ERROR)
         {
            // use the global or local color table ?
            GifColorType *color = gifinfo->SColorMap->Colors;
            if (gifinfo->Image.ColorMap)
               color = gifinfo->Image.ColorMap->Colors;

            if (color)
            {
               U8 *dst = getAddress(gifinfo->Image.Left, gifinfo->Image.Top);
               U8 *src = data;
               U32 right  = gifinfo->Image.Left + gwidth;
               U32 bottom = gifinfo->Image.Top + gheight;
               U32 next   = (width - gwidth) * bytesPerPixel;

               if (format == RGBA)
               {
                  for (U32 y=gifinfo->Image.Top; y<bottom; y++)
                  {
                     for (U32 x=gifinfo->Image.Left; x<right; x++, src++)
                     {
                        if (*src == gifinfo->SBackGroundColor)
                        {
                           // this is a transparent pixel
                           dst[0] = 0;    // red
                           dst[1] = 0;    // green
                           dst[2] = 0;    // blue
                           dst[3] = 0;    // alpha
                        }
                        else
                        {
                           dst[0] = color[*src].Red;
                           dst[1] = color[*src].Green;
                           dst[2] = color[*src].Blue;
                           dst[3] = 0;    // alpha
                        }
                        dst += bytesPerPixel;
                     }
                     dst += next;
                  }
               }
               else
               {
                  for (U32 y=gifinfo->Image.Top; y<bottom; y++)
                  {
                     for (U32 x=gifinfo->Image.Left; x<right; x++, src++)
                     {
                        dst[0] = color[*src].Red;
                        dst[1] = color[*src].Green;
                        dst[2] = color[*src].Blue;
                        dst += bytesPerPixel;
                     }
                     dst += next;
                  }
               }
               delete [] data;
               DGifCloseFile(gifinfo);
               return true;
            }
         }
         // failure
         delete [] data;
         break;
      }
      else if (recordType == EXTENSION_RECORD_TYPE)
      {
         GifByteType *extension;
         S32 extCode;

         // Skip any extension blocks in file
         if (DGifGetExtension(gifinfo, &extCode, &extension) != GIF_ERROR)
         {
            while (extension != NULL)
            {
               if (DGifGetExtensionNext(gifinfo, &extension) == GIF_ERROR)
                  return false;
            }
         }
         else
            return false;
      }

      break;

   }while (recordType != TERMINATE_RECORD_TYPE);


   DGifCloseFile(gifinfo);
   return false;
}


//--------------------------------------------------------------------------
bool GBitmap::writeGIF(Stream&) const
{
   return false;
}