#include <osg/Image>
#include <osg/Image>
#include <osg/Input>
#include <osg/Output>
#include <osg/Notify>
#include <osg/Registry>
#include <osg/Geode>

#include <osg/GL>


/****************************************************************************
 *
 * Follows is code extracted from the simage library.  Original Authors:
 *
 *      Systems in Motion, 
 *      <URL:http://www.sim.no>
 * 
 *      Peder Blekken <pederb@sim.no>
 *      Morten Eriksen <mortene@sim.no>
 *      Marius Bugge Monsen <mariusbu@sim.no>     
 *
 * The original COPYING notice                                      
 *
 *      All files in this library are public domain, except simage_rgb.cpp which is 
 *      Copyright (c) Mark J Kilgard <mjk@nvidia.com>. I will contact Mark
 *      very soon to hear if this source also can become public domain.
 *
 *      Please send patches for bugs and new features to: <pederb@sim.no>.
 *
 *      Peder Blekken
 *
 *
 * Ported into the OSG as a plugin, Robert Osfield Decemeber 2000.
 * Note, reference above to license of simage_rgb is not relevent to the OSG
 * as the OSG does not use it.  Also for patches, bugs and new features
 * please send them direct to the OSG dev team rather than address above.
 *
 **********************************************************************/

/*
 * Based on example code found in the libjpeg archive
 *
 */

#include <stdio.h>

extern "C" {
#include <jpeglib.h>
};

#include <setjmp.h>
#include <string.h>
#include <assert.h>
#include <stdlib.h>

#define ERR_NO_ERROR 0
#define ERR_OPEN     1
#define ERR_MEM      2
#define ERR_JPEGLIB  3

static int jpegerror = ERR_NO_ERROR;

int
simage_jpeg_error(char * buffer, int buflen)
{
  switch (jpegerror) {
  case ERR_OPEN:
    strncpy(buffer, "JPEG loader: Error opening file", buflen);
    break;
  case ERR_MEM:
    strncpy(buffer, "JPEG loader: Out of memory error", buflen);
    break;
  case ERR_JPEGLIB:
    strncpy(buffer, "JPEG loader: Illegal jpeg file", buflen);
    break;
  }
  return jpegerror;
}

struct my_error_mgr {
  struct jpeg_error_mgr pub;    /* "public" fields */

  jmp_buf setjmp_buffer;        /* for return to caller */
};


typedef struct my_error_mgr * my_error_ptr;

static void 
my_error_exit (j_common_ptr cinfo)
{
  /* cinfo->err really points to a my_error_mgr struct, so coerce pointer */
  my_error_ptr myerr = (my_error_ptr) cinfo->err;

  /* Always display the message. */
  /* We could postpone this until after returning, if we chose. */
  /*(*cinfo->err->output_message) (cinfo);*/

  /* FIXME: get error messahe from jpeglib */

  /* Return control to the setjmp point */
  longjmp(myerr->setjmp_buffer, 1);
}

int 
simage_jpeg_identify(const char * ptr,
		     const unsigned char *header,
		     int headerlen)
{
  static unsigned char jpgcmp[] = {'J', 'F', 'I', 'F' };
  if (headerlen < 4) return 0;
  if (memcmp((const void*)&header[6], 
	     (const void*)jpgcmp, 4) == 0) return 1;
  return 0;
}


static unsigned char*
copyScanline(unsigned char *currPtr, unsigned char *from, int cnt)
{
  memcpy((void*)currPtr, (void*)from, cnt);
  currPtr -= cnt;
  return currPtr;
}

  
unsigned char *
simage_jpeg_load(const char *filename,
		 int *width_ret,
		 int *height_ret,
		 int *numComponents_ret)
{
  int width;
  int height;
  unsigned char *currPtr;
  int format;
  unsigned char *buffer;
  /* This struct contains the JPEG decompression parameters and pointers to
   * working space (which is allocated as needed by the JPEG library).
   */
  struct jpeg_decompress_struct cinfo;
  /* We use our private extension JPEG error handler.
   * Note that this struct must live as long as the main JPEG parameter
   * struct, to avoid dangling-pointer problems.
   */
  struct my_error_mgr jerr;
  /* More stuff */
  FILE * infile;                /* source file */
  JSAMPARRAY rowbuffer;            /* Output row buffer */
  int row_stride;               /* physical row width in output buffer */

  jpegerror = ERR_NO_ERROR;

  /* In this example we want to open the input file before doing anything else,
   * so that the setjmp() error recovery below can assume the file is open.
   * VERY IMPORTANT: use "b" option to fopen() if you are on a machine that
   * requires it in order to read binary files.
   */

  if ((infile = fopen(filename, "rb")) == NULL) {
    jpegerror = ERR_OPEN;
    return NULL;
  }

  /* Step 1: allocate and initialize JPEG decompression object */

  buffer = NULL;

  /* We set up the normal JPEG error routines, then override error_exit. */
  cinfo.err = jpeg_std_error(&jerr.pub);
  jerr.pub.error_exit = my_error_exit;
  /* Establish the setjmp return context for my_error_exit to use. */
  if (setjmp(jerr.setjmp_buffer)) {
    /* If we get here, the JPEG code has signaled an error.
     * We need to clean up the JPEG object, close the input file, and return.
     */
    jpegerror = ERR_JPEGLIB;
    jpeg_destroy_decompress(&cinfo);
    fclose(infile);
    if (buffer) free(buffer);
    return NULL;
  }
  /* Now we can initialize the JPEG decompression object. */
  jpeg_create_decompress(&cinfo);

  /* Step 2: specify data source (eg, a file) */

  jpeg_stdio_src(&cinfo, infile);

  /* Step 3: read file parameters with jpeg_read_header() */

  (void) jpeg_read_header(&cinfo, TRUE);
  /* We can ignore the return value from jpeg_read_header since
   *   (a) suspension is not possible with the stdio data source, and
   *   (b) we passed TRUE to reject a tables-only JPEG file as an error.
   * See libjpeg.doc for more info.
   */

  /* Step 4: set parameters for decompression */
  /* In this example, we don't need to change any of the defaults set by
   * jpeg_read_header(), so we do nothing here.
   */

  /* Step 5: Start decompressor */
  if (cinfo.jpeg_color_space == JCS_GRAYSCALE) {
    format = 1;
    cinfo.out_color_space = JCS_GRAYSCALE;
  }
  else { /* use rgb */
    format = 3;
    cinfo.out_color_space = JCS_RGB;
  }
  
  (void) jpeg_start_decompress(&cinfo);
  /* We can ignore the return value since suspension is not possible
   * with the stdio data source.
   */

  /* We may need to do some setup of our own at this point before reading
   * the data.  After jpeg_start_decompress() we have the correct scaled
   * output image dimensions available, as well as the output colormap
   * if we asked for color quantization.
   * In this example, we need to make an output work buffer of the right size.
   */
  /* JSAMPLEs per row in output buffer */
  row_stride = cinfo.output_width * cinfo.output_components;
  /* Make a one-row-high sample array that will go away when done with image */
  rowbuffer = (*cinfo.mem->alloc_sarray)
    ((j_common_ptr) &cinfo, JPOOL_IMAGE, row_stride, 1);
  width = cinfo.output_width;
  height = cinfo.output_height;
  buffer = currPtr = (unsigned char*) 
    malloc(width*height*cinfo.output_components);
  
  /* Step 6: while (scan lines remain to be read) */
  /*           jpeg_read_scanlines(...); */

  /* Here we use the library's state variable cinfo.output_scanline as the
   * loop counter, so that we don't have to keep track ourselves.
   */
  
  /* flip image upside down */
  if (buffer) {
    currPtr = buffer + row_stride * (cinfo.output_height-1);  
    
    while (cinfo.output_scanline < cinfo.output_height) {
      /* jpeg_read_scanlines expects an array of pointers to scanlines.
       * Here the array is only one element long, but you could ask for
       * more than one scanline at a time if that's more convenient.
       */
      (void) jpeg_read_scanlines(&cinfo, rowbuffer, 1);
      /* Assume put_scanline_someplace wants a pointer and sample count. */
      currPtr = copyScanline(currPtr, rowbuffer[0], row_stride);
    }
  }
  /* Step 7: Finish decompression */

  (void) jpeg_finish_decompress(&cinfo);
  /* We can ignore the return value since suspension is not possible
   * with the stdio data source.
   */

  /* Step 8: Release JPEG decompression object */

  /* This is an important step since it will release a good deal of memory. */
  jpeg_destroy_decompress(&cinfo);

  /* After finish_decompress, we can close the input file.
   * Here we postpone it until after no more JPEG errors are possible,
   * so as to simplify the setjmp error logic above.  (Actually, I don't
   * think that jpeg_destroy can do an error exit, but why assume anything...)
   */
  fclose(infile);

  /* At this point you may want to check to see whether any corrupt-data
   * warnings occurred (test whether jerr.pub.num_warnings is nonzero).
   */

  /* And we're done! */
  if (buffer) {
    *width_ret = width;
    *height_ret = height;
    *numComponents_ret = format;
  }
  else {
    jpegerror = ERR_MEM;
  }
  return buffer;
}

class ReaderWriterJPEG : public osg::ReaderWriter
{
    public:
        virtual const char* className() { return "JPEG Image Reader"; }
        virtual bool acceptsExtension(const std::string& extension) { return extension=="jpeg"; }

        virtual osg::Node* readNode(const std::string& fileName)
        {
            osg::Image* image = readImage(fileName);
            if (image)
            {
                osg::Geode* geode = osg::createGeodeForImage(image);
                if (geode==NULL) image->unref();
                return geode;
            }
            else
            {
                return NULL;
            }
        }

        virtual osg::Image* readImage(const std::string& fileName)
        {

            unsigned char *imageData = NULL;
            int width_ret;
            int height_ret;
            int numComponents_ret;

            imageData = simage_jpeg_load(fileName.c_str(),&width_ret,&height_ret,&numComponents_ret);
	    
            if (imageData==NULL) return NULL;

            int s = width_ret;
            int t = height_ret;
            int r = 1;

            int internalFormat = numComponents_ret;

            unsigned int pixelFormat =
                numComponents_ret == 1 ? GL_LUMINANCE :
                numComponents_ret == 2 ? GL_LUMINANCE_ALPHA :
                numComponents_ret == 3 ? GL_RGB :
                numComponents_ret == 4 ? GL_RGBA : (GLenum)-1;

            unsigned int dataType = GL_UNSIGNED_BYTE;

            osg::Image* pOsgImage = new osg::Image;
            pOsgImage->setFileName(fileName.c_str());
	    pOsgImage->setImage(s,t,r,
                                internalFormat,
                                pixelFormat,
                                dataType,
                                imageData);

            return pOsgImage;

        }
};

// now register with Registry to instantiate the above
// reader/writer.
osg::RegisterReaderWriterProxy<ReaderWriterJPEG> g_readerWriter_JPEG_Proxy;