#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdio.h>
#include <iostream>
#include <sstream>

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

#include "JPEGWriter.h"
#define JPEG_IOBUFFER_SIZE (16 * 1024)

using namespace std;

struct jpeg_destination_handler {
  JOCTET *buffer;
  std::ostream *os_ptr;
};

static  void init_destination (j_compress_ptr);
static  boolean empty_output_buffer (j_compress_ptr);
static  void term_destination (j_compress_ptr);

namespace tlprender {
  JPEGWriter::JPEGWriter(const GLubyte *imagebuffer, const int width, const int height) :
    ImageWriter(imagebuffer, width, height) {}

  JPEGWriter::~JPEGWriter() {}

  bool JPEGWriter::writeImage(std::ostream &os) const
  {        
    struct jpeg_compress_struct cinfo;
    struct jpeg_error_mgr jerr;

    jpeg_create_compress(&cinfo);
    cinfo.err = jpeg_std_error(&jerr);
    cinfo.image_width = width;
    cinfo.image_height = height;
    cinfo.input_components = 3;
    cinfo.in_color_space = JCS_RGB;

    struct jpeg_destination_mgr dest_mgr;
    dest_mgr.init_destination = &init_destination;
    dest_mgr.empty_output_buffer = &empty_output_buffer;
    dest_mgr.term_destination = &term_destination;

    cinfo.dest = &dest_mgr;
    cinfo.client_data = &os;
    
    jpeg_set_defaults(&cinfo);
    jpeg_set_quality(&cinfo, 255, FALSE);

    jpeg_start_compress(&cinfo, TRUE);

    stringstream ss;
    if (titleState) ss << "Title: " << title << endl;
    if (softwareState) ss << "Software: " << software << endl;
    if (sourceState) ss << "Source: " << source << endl;
    if (layoutState) ss << "Layout: " << layout << endl;
    if (commentState) ss << "Comment: " << comment << endl;
    jpeg_write_marker(&cinfo, JPEG_COM, (const JOCTET *) ss.str().c_str(), ss.str().length());
    
    JSAMPROW row_pointer = new JSAMPLE[width * 3];
    while (cinfo.next_scanline < cinfo.image_height) {
      const GLubyte *offset = & buffer[width * (cinfo.image_height - cinfo.next_scanline) * 4 * sizeof(GLubyte)];
      for (int i=0; i < width; ++i) {
	memcpy(row_pointer+(i*3), offset+(i*4), 3);
      }
      jpeg_write_scanlines(&cinfo, &row_pointer, 1);
    }
    delete [] row_pointer;
    
    jpeg_finish_compress(&cinfo);
    jpeg_destroy_compress(&cinfo);
    return true;
  }
}

static void init_destination (j_compress_ptr cinfo)
{
  struct jpeg_destination_handler *dest_handler = new struct jpeg_destination_handler;
  dest_handler->buffer = new JOCTET[JPEG_IOBUFFER_SIZE];
  dest_handler->os_ptr = (std::ostream *) cinfo->client_data;
  cinfo->client_data = dest_handler;
  cinfo->dest->next_output_byte = dest_handler->buffer;
  cinfo->dest->free_in_buffer = JPEG_IOBUFFER_SIZE;
}

static boolean empty_output_buffer (j_compress_ptr cinfo)
{
  struct jpeg_destination_handler *dest_handler = (struct jpeg_destination_handler *) cinfo->client_data;
  for (int i=0; i < JPEG_IOBUFFER_SIZE; ++i) {
    *(dest_handler->os_ptr) << (dest_handler->buffer)[i];
  }
  cinfo->dest->next_output_byte = dest_handler->buffer;
  cinfo->dest->free_in_buffer = JPEG_IOBUFFER_SIZE;
  return TRUE;
}

static void term_destination (j_compress_ptr cinfo)
{
  struct jpeg_destination_handler *dest_handler = (struct jpeg_destination_handler *) cinfo->client_data;
  for (size_t i=0; i < (JPEG_IOBUFFER_SIZE - cinfo->dest->free_in_buffer); ++i) {
    *(dest_handler->os_ptr) << (dest_handler->buffer)[i];
  }
  dest_handler->os_ptr->flush();
  delete dest_handler->buffer;
  delete dest_handler;
}