/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/***************************************************************************
 *            image.cc
 *
 *  Sat Mar 16 15:05:09 CET 2013
 *  Copyright 2013 Bent Bisballe Nyeng
 *  deva@aasimon.org
 ****************************************************************************/

/*
 *  This file is part of DrumGizmo.
 *
 *  DrumGizmo 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.
 *
 *  DrumGizmo 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 DrumGizmo; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
 */
#include "image.h"

#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <stdarg.h>

void abort_(const char * s, ...)
{
  va_list args;
  va_start(args, s);
  vfprintf(stderr, s, args);
  fprintf(stderr, "\n");
  va_end(args);
  abort();
}

GUI::Image::Image(const char* data, size_t size)
{
}

GUI::Image::Image(std::string filename)
{
  char header[8];    // 8 is the maximum size that can be checked

  /* open file and test for it being a png */
  FILE *fp = fopen(filename.c_str(), "rb");
  if (!fp)
    abort_("[read_png_file] File %s could not be opened for reading",
           filename.c_str());
  size_t r = fread(header, 1, 8, fp);
  (void)r;
  if(png_sig_cmp((const png_byte*)header, 0, 8)) {
    abort_("[read_png_file] File %s is not recognized as a PNG file",
           filename.c_str());
  }
  
  /* initialize stuff */
  png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
  
  if(!png_ptr) {
    abort_("[read_png_file] png_create_read_struct failed");
  }
  
  info_ptr = png_create_info_struct(png_ptr);
  if(!info_ptr) {
    abort_("[read_png_file] png_create_info_struct failed");
  }
  
  if(setjmp(png_jmpbuf(png_ptr))) {
    abort_("[read_png_file] Error during init_io");
  }
  
  png_init_io(png_ptr, fp);
  png_set_sig_bytes(png_ptr, 8);
  
  png_read_info(png_ptr, info_ptr);
  
  w = png_get_image_width(png_ptr, info_ptr);
  h = png_get_image_height(png_ptr, info_ptr);
  color_type = png_get_color_type(png_ptr, info_ptr);
  bit_depth = png_get_bit_depth(png_ptr, info_ptr);
  
  number_of_passes = png_set_interlace_handling(png_ptr);
  png_read_update_info(png_ptr, info_ptr);
  
  
  /* read file */
  if (setjmp(png_jmpbuf(png_ptr))) {
    abort_("[read_png_file] Error during read_image");
  }
  
  row_pointers = (png_bytep*) malloc(sizeof(png_bytep) * h);
  size_t y;
  for(y = 0; y < h; y++) {
    row_pointers[y] = (png_byte*) malloc(png_get_rowbytes(png_ptr,info_ptr));
  }
  
  png_read_image(png_ptr, row_pointers);
  
  fclose(fp);
}
#if 0
void process_file(void)
{
  if(png_get_color_type(png_ptr, info_ptr) == PNG_COLOR_TYPE_RGB) {
    abort_("[process_file] input file is PNG_COLOR_TYPE_RGB but must be"
           " PNG_COLOR_TYPE_RGBA (lacks the alpha channel)");
  }

  if(png_get_color_type(png_ptr, info_ptr) != PNG_COLOR_TYPE_RGBA) {
    abort_("[process_file] color_type of input file must be "
           "PNG_COLOR_TYPE_RGBA (%d) (is %d)",
           PNG_COLOR_TYPE_RGBA, png_get_color_type(png_ptr, info_ptr));
  }

  size_t x, y; 
  for(y = 0; y < height(); y++) {
    png_byte* row = row_pointers[y];
    for(x = 0; x < width; x++) {
      png_byte* ptr = &(row[x*4]);
      printf("Pixel at position [%d - %d] has RGBA values: %d - %d - %d - %d\n",
             x, y, ptr[0], ptr[1], ptr[2], ptr[3]);
      
      /* set red value to 0 and green value to the blue one */
      ptr[0] = 0;
      ptr[1] = ptr[2];
    }
  }
}
#endif

GUI::Image::~Image()
{
}

size_t GUI::Image::width()
{
  return w;
}

size_t GUI::Image::height()
{
  return h;
}

GUI::Colour GUI::Image::getPixel(size_t x, size_t y)
{
  png_byte* row = row_pointers[y];
  png_byte* ptr = &(row[x*4]);
  GUI::Colour c(ptr[0], ptr[1], ptr[2], ptr[3]);
  return c;
}