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

#include <jpeglib.h>
#include <argtable2.h>
#include <string.h>

const char * input_file;
const char * output_file;
const char * filter;
const char * axis;
const char * direction; 
double times;

/* we will be using this uninitialized pointer later to store raw, uncompressd image */
JSAMPARRAY row_pointers = NULL;

/* dimensions of the image we want to write */
JDIMENSION width;
JDIMENSION height;
int num_components;
int quality = 75;
J_COLOR_SPACE color_space;

void flip(){
  int x, y;
  if (color_space != JCS_RGB)  return;

  for (y=0; y<height; y++) {
    JSAMPROW row = row_pointers[y];
    for (x=0; x<width/2; x++) {
      JSAMPROW ptr = &(row[x*3]);
      JSAMPROW ptr2 = &(row[(width-1-x)*3]);

      JSAMPLE tmp;
      tmp=ptr[0]; ptr[0]=ptr2[0]; ptr2[0]=tmp;
      tmp=ptr[1]; ptr[1]=ptr2[1]; ptr2[1]=tmp;
      tmp=ptr[2]; ptr[2]=ptr2[2]; ptr2[2]=tmp;
    }
  }
}    

void rotate(){
  int x, y;
  if (color_space != JCS_RGB) return;

  JDIMENSION new_width = height;
  JDIMENSION new_height = width;
  
  size_t rowbytes = new_width * num_components;
  JSAMPARRAY new_row_pointers = (JSAMPARRAY) malloc(sizeof(j_common_ptr) * new_height);
  for (y=0; y<new_height; y++){
      new_row_pointers[y] = (JSAMPROW) malloc(rowbytes);
  }

  if (strcmp(direction, "left") == 0) {
      for (y=0; y<height; y++) {
          for (x=0; x<width; x++) {
              int new_x = y;
              int new_y = width - 1 - x;
              new_row_pointers[new_y][new_x*3] = row_pointers[y][x*3];
              new_row_pointers[new_y][new_x*3+1] = row_pointers[y][x*3+1];
              new_row_pointers[new_y][new_x*3+2] = row_pointers[y][x*3+2];
          }
      }
  } 
  else if (strcmp(direction, "right") == 0) {
      for (y=0; y<height; y++) {
          for (x=0; x<width; x++) {
              int new_x = height - 1 - y;
              int new_y = x;
              new_row_pointers[new_y][new_x*3] = row_pointers[y][x*3];
              new_row_pointers[new_y][new_x*3+1] = row_pointers[y][x*3+1];
              new_row_pointers[new_y][new_x*3+2] = row_pointers[y][x*3+2];
          }
      }
  }

  for (y=0; y<height; y++){
      free(row_pointers[y]);
  }
  free(row_pointers);
  
  row_pointers = new_row_pointers;
  width = new_width;
  height = new_height;
}

void process_file(){
    if(strcmp(filter, "flip") == 0 ){
        if(strcmp(axis, "x") == 0) {
            int y;
            for(y=0; y<height/2; y++) {
                JSAMPROW temp = row_pointers[y];
                row_pointers[y] = row_pointers[height - 1 - y];
                row_pointers[height - 1 - y] = temp;
            }
        } else {
            flip();
        }
    }
    if(strcmp(filter, "rotate") == 0 ){
        rotate();
    }
}

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

void read_jpeg_file( const char *filename )
{
	struct jpeg_decompress_struct cinfo;
	struct jpeg_error_mgr jerr;
	int y;
	
	FILE *infile = fopen( filename, "rb" );
	
	if ( !infile )
	{
		abort_("Error opening input jpeg file %s!\n", filename);
	}
	cinfo.err = jpeg_std_error( &jerr );
	jpeg_create_decompress( &cinfo );
	jpeg_stdio_src( &cinfo, infile );
	jpeg_read_header( &cinfo, TRUE );

	jpeg_start_decompress( &cinfo );
	width = cinfo.output_width;
	height = cinfo.output_height;
	num_components = cinfo.out_color_components;
	color_space = cinfo.out_color_space;
	
	size_t rowbytes = width * num_components;
	row_pointers = (JSAMPARRAY) malloc(sizeof(j_common_ptr) * height);
	for (y=0; y<height; y++){
		row_pointers[y] = (JSAMPROW) malloc(rowbytes);
	}

	y=0;
	JSAMPARRAY tmp = row_pointers;
	while( cinfo.output_scanline < cinfo.image_height )
	{
		y = jpeg_read_scanlines( &cinfo, tmp, 1 );
		tmp +=y;
	}
	jpeg_finish_decompress( &cinfo );
	jpeg_destroy_decompress( &cinfo );
	fclose( infile );
}

void write_jpeg_file( const char *filename )
{
	struct jpeg_compress_struct cinfo;
	struct jpeg_error_mgr jerr;
	int y;
	JSAMPARRAY tmp;

	FILE *outfile = fopen( filename, "wb" );
	
	if ( !outfile )	{
		abort_("Error opening output jpeg file %s!\n", filename );
	}
	cinfo.err = jpeg_std_error( &jerr );
	jpeg_create_compress(&cinfo);
	jpeg_stdio_dest(&cinfo, outfile);

	cinfo.image_width = width;	
	cinfo.image_height = height;
	cinfo.input_components = num_components;
	cinfo.in_color_space = color_space;
    jpeg_set_defaults( &cinfo );
	jpeg_set_quality (&cinfo, quality, TRUE);
	jpeg_start_compress( &cinfo, TRUE );
	tmp = row_pointers;
	while( cinfo.next_scanline < cinfo.image_height )
	{
		y = jpeg_write_scanlines( &cinfo, tmp, 1 );
		tmp +=y;
	}
	jpeg_finish_compress( &cinfo );
	jpeg_destroy_compress( &cinfo );
	fclose( outfile );
	
    for (y=0; y<height; y++){
		free(row_pointers[y]);
	}
	free(row_pointers);
}

int main(int argc, char **argv){  
  struct arg_file *input_file_arg = arg_file1("i", "in-file", "<input>", "Input JPEG File");
  struct arg_file *output_file_arg = arg_file1("o", "out-file" , "<output>", "Output JPEG File");
  struct arg_str *filter_arg = arg_str1("f", "filter" , "<filter>", "Filter");
  struct arg_str *axis_arg = arg_str0("a","axis","<axis>","Flip axis (x/y)");
  struct arg_str *direction_arg = arg_str0("d","direction","<direction>","Rotation direction (left/right)");
  struct arg_dbl *times_arg = arg_dbl0("t", "times" , "<times>", "Multiplyer");
  struct arg_lit *help = arg_lit0("h","help", "print this help and exit");
  struct arg_end *end = arg_end(10); // maksymalna liczba błędów 10
  
  int nerrors;
  
  void *argtable[] = {input_file_arg, output_file_arg, filter_arg, axis_arg, direction_arg, times_arg, help, end};
  
  if (arg_nullcheck(argtable) != 0) printf("error: insufficient memory\n");
  
  times_arg->dval[0] = 1;
  axis_arg->sval[0] = "y";
  direction_arg->sval[0] = "right";
  
  nerrors = arg_parse(argc, argv, argtable);
  
  if (help->count > 0){
     printf("Usage: geometry");
     arg_print_syntax(stdout, argtable,"\n");
     arg_print_glossary(stdout, argtable,"  %-25s %s\n");
     arg_freetable(argtable, sizeof(argtable)/sizeof(argtable[0]));
     return 0;
  }

  if (nerrors==0){
     input_file = input_file_arg->filename[0];
     output_file = output_file_arg->filename[0];
     filter = filter_arg->sval[0];
     axis = axis_arg->sval[0];
     times = times_arg->dval[0];
     direction = direction_arg->sval[0];
  }
  else{
     arg_print_errors(stderr, end, "point");
     arg_print_glossary(stderr, argtable, " %-25s %s\n");
     arg_freetable(argtable, sizeof(argtable)/sizeof(argtable[0]));
     return 1;
  }

   read_jpeg_file(input_file);
   process_file();
   write_jpeg_file(output_file);
   arg_freetable(argtable, sizeof(argtable)/sizeof(argtable[0]));
   return 0;
}