//----------------------------------------------------------------------------

#ifndef NETPBM_H
#define NETPBM_H

#include <stdbool.h>
#include <stdint.h>

bool // success
Netpbm_saveP3(const char *fileName,
              int width,
              int height,
              uint8_t *contents);

uint8_t * // loaded contents or NULL
Netpbm_loadP3(const char *fileName,
              int *out_width,
              int *out_height);

bool // success
Netpbm_saveP6(const char *fileName,
              int width,
              int height,
              uint8_t *contents);

uint8_t * // loaded contents or NULL
Netpbm_loadP6(const char *fileName,
              int *out_width,
              int *out_height);

#endif // NETPBM_H

//----------------------------------------------------------------------------

//----------------------------------------------------------------------------

#include "netpbm.h"
#include <stdio.h>
#include <stdlib.h>

bool // success
Netpbm_saveP3(const char *fileName,
              int width,
              int height,
              uint8_t *contents)
{
  FILE *f=fopen(fileName, "w");
  if(f==NULL)
  {
    return false;
  }
  fprintf(f, "P3\n%d %d\n255\n", width, height);
  int byteCount=3*width*height;
  for(int i=0; i<byteCount; ++i)
  {
    fprintf(f, "%d\n", contents[i]);
  }
  fclose(f);
  return true;
}

uint8_t * // loaded contents or NULL
Netpbm_loadP3(const char *fileName,
              int *out_width,
              int *out_height)
{
  FILE *f=fopen(fileName, "r");
  if(f==NULL)
  {
    return NULL;
  }
  int width, height, range;
  if((fscanf(f, "P3 %d %d %d", &width, &height, &range)!=3)||
     (width<=0)||(height<=0)||(range!=255))
  {
    fclose(f);
    return NULL;
  }
  int byteCount=3*width*height;
  uint8_t *contents=(uint8_t *)malloc(byteCount);
  if(contents==NULL)
  {
    abort();
  }
  for(int i=0; i<byteCount; ++i)
  {
#if 1 // first version
    int value;
    if(fscanf(f, "%d", &value)!=1)
    {
      free(contents);
      fclose(f);
      return NULL;
    }
    contents[i]=(uint8_t)value;
#else // second version
    if(fscanf(f, "%hhu", contents+i)!=1)
    {
      free(contents);
      fclose(f);
      return NULL;
    }
#endif
  }
  fclose(f);
  //-- store out-parameters --
  *out_width=width;
  *out_height=height;
  return contents;
}

bool // success
Netpbm_saveP6(const char *fileName,
              int width,
              int height,
              uint8_t *contents)
{
  FILE *f=fopen(fileName, "wb");
  if(f==NULL)
  {
    return false;
  }
  fprintf(f, "P6\n%d %d\n255\n", width, height);
  int byteCount=3*width*height;
  fwrite(contents, byteCount, 1, f);
  fclose(f);
  return true;
}

uint8_t * // loaded contents or NULL
Netpbm_loadP6(const char *fileName,
              int *out_width,
              int *out_height)
{
  FILE *f=fopen(fileName, "rb");
  if(f==NULL)
  {
    return NULL;
  }
  int width, height, range;
  if((fscanf(f, "P6 %d %d %d\n", &width, &height, &range)!=3)||
     (width<=0)||(height<=0)||(range!=255))
  {
    fclose(f);
    return NULL;
  }
  int byteCount=3*width*height;
  uint8_t *contents=(uint8_t *)malloc(byteCount);
  if(contents==NULL)
  {
    abort();
  }
  if(fread(contents, byteCount, 1, f)!=1)
  {
    free(contents);
    fclose(f);
    return NULL;
  }
  fclose(f);
  //-- store out-parameters --
  *out_width=width;
  *out_height=height;
  return contents;
}

//----------------------------------------------------------------------------

//----------------------------------------------------------------------------

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "netpbm.h"

void
test_output(const char *s)
{
  printf("\n~~~~ %s() ~~~~\n", __func__);
  int i=1234;
  double d=12.34;
  char c='A';
  printf("i=%d d=%g c=%c s=%s\n", i, d, c, s);
#if 0
  char line[100]; // large enough
#else
  char line[30]; // a bit too small
#endif
  snprintf(line, sizeof(line), "i=%d d=%g c=%c s=%s", i, d, c, s);
  printf("<%s>\n", line);
  fprintf(stdout, "stdout: <%s>\n", line);
  fprintf(stderr, "stderr: <%s>\n", line);
  //
  const char *input_line_1="X 1234";
  char my_char;
  int my_int;
  if(sscanf(input_line_1, "%c %d", &my_char, &my_int)==2)
  {
    printf("a char <%c> and an integer <%d>\n",
           my_char, my_int);
  }
  else // 2 successful extractions were expected
  {
    fprintf(stderr, "cannot extract a char and an integer\n");
  }
  const char *input_line_2="12.34 56.78e300 hello";
  float my_float;
  double my_double;
  char my_word[100];
  if(sscanf(input_line_2, "%f %lf %s", &my_float, &my_double, my_word)==3)
  {
    printf("a float <%g>, a double <%g> and a word <%s>\n",
           my_float, my_double, my_word);
  }
  else // 3 successful extractions were expected
  {
    fprintf(stderr, "cannot extract a float, a double and a word\n");
  }
}

void
test_txtWrite(const char *fileName)
{
  printf("\n~~~~ %s(%s) ~~~~\n", __func__, fileName);
  FILE *f=fopen(fileName, "w");
  if(f==NULL)
  {
    fprintf(stderr, "cannot open %s\n", fileName);
    return;
  }
  int i=1234;
  double d=12.34;
  char c='A';
  char s[]="hello";
  fprintf(f, "an integer: %d\n", i);
  fprintf(f, "a real: %g\n", d);
  fprintf(f, "a char: %c\n", c);
  fprintf(f, "a string: %s\n", s);
  fclose(f);
}

void
test_saveP3(const char *fileName,
            int width,
            int height)
{
  printf("\n~~~~ %s(%s, %d, %d) ~~~~\n", __func__, fileName, width, height);
  int byteCount=3*width*height;
  uint8_t *contents=(uint8_t *)malloc(byteCount);
  if(contents==NULL)
  {
    abort();
  }
  for(int y=0; y<height; ++y)
  {
    for(int x=0; x<width; ++x)
    {
      int red=255*x/(width-1);
      int green=255*y/(height-1);
      int blue=255-(red+green)/2;
      int idx=3*(y*width+x);
      contents[idx+0]=(uint8_t)red;
      contents[idx+1]=(uint8_t)green;
      contents[idx+2]=(uint8_t)blue;
    }
  }
  if(!Netpbm_saveP3(fileName, width, height, contents))
  {
    fprintf(stderr, "cannot save %s\n", fileName);
  }
  free(contents);
}

void
test_input(void)
{
  printf("\n~~~~ %s() ~~~~\n", __func__);
  char fileName[100]="";
  int width=0, height=0;
#if 0 // first version
  printf("file name?\n");
  scanf("%s", fileName);
  printf("image size (width x height)?\n");
  scanf("%d x%d", &width, &height);
#else // second version
  char line[100];
  do
  {
    printf("file name?\n");
    if(!fgets(line, sizeof(line), stdin))
    {
      return;
    }
  } while(sscanf(line, "%s", fileName)!=1);
  do
  {
    printf("image size (width x height)?\n");
    if(!fgets(line, sizeof(line), stdin))
    {
      return;
    }
  } while(sscanf(line, "%d x%d", &width, &height)!=2);
#endif
  if(fileName[0]&&(width>0)&&(height>0))
  {
    test_saveP3(fileName, width, height);
  }
}

void
test_loadP3(const char *inputFileName,
            const char *outputFileName)
{
  printf("\n~~~~ %s(%s, %s) ~~~~\n", __func__, inputFileName, outputFileName);
  int width, height;
  uint8_t *contents=Netpbm_loadP3(inputFileName, &width, &height);
  if(contents==NULL)
  {
    fprintf(stderr, "cannot load %s\n", inputFileName);
    return;
  }
  printf("width=%d height=%d\n", width, height);
  int byteCount=3*width*height;
  for(int i=0; i<byteCount; i+=3)
  {
    uint8_t red=contents[i+0], green=contents[i+1], blue=contents[i+2];
    contents[i+0]=blue;
    contents[i+1]=red;
    contents[i+2]=green;
  }
  if(!Netpbm_saveP3(outputFileName, width, height, contents))
  {
    fprintf(stderr, "cannot save %s\n", outputFileName);
  }
  free(contents);
}

void
test_binWrite(const char *fileName)
{
  printf("\n~~~~ %s(%s) ~~~~\n", __func__, fileName);
  int iArray[5]={10, 20, 30, 40, 50};
  double dArray[4]={10.01, 20.02, 30.03, 40.04};
  for(int i=0; i<5; ++i)
  {
    printf("%d ", iArray[i]);
  }
  printf("\n");
  for(int i=0; i<4; ++i)
  {
    printf("%g ", dArray[i]);
  }
  printf("\n");
  FILE *f=fopen(fileName, "wb");
  if(f==NULL)
  {
    fprintf(stderr, "cannot open %s\n", fileName);
    return;
  }
  if(fwrite(iArray, sizeof(int), 5, f)!=5)
  {
    fprintf(stderr, "cannot write to %s\n", fileName);
    fclose(f);
    return;
  }
  if(fwrite(dArray, sizeof(double), 4, f)!=4)
  {
    fprintf(stderr, "cannot write to %s\n", fileName);
    fclose(f);
    return;
  }
  fclose(f);
}

void
test_binRead(const char *fileName)
{
  printf("\n~~~~ %s(%s) ~~~~\n", __func__, fileName);
  int iArray[5];
  double dArray[4];
  FILE *f=fopen(fileName, "rb");
  if(f==NULL)
  {
    fprintf(stderr, "cannot open %s\n", fileName);
    return;
  }
  if(fread(iArray, sizeof(int), 5, f)!=5)
  {
    fprintf(stderr, "cannot read from %s\n", fileName);
    fclose(f);
    return;
  }
  if(fread(dArray, sizeof(double), 4, f)!=4)
  {
    fprintf(stderr, "cannot read from %s\n", fileName);
    fclose(f);
    return;
  }
  fclose(f);
  for(int i=0; i<5; ++i)
  {
    printf("%d ", iArray[i]);
  }
  printf("\n");
  for(int i=0; i<4; ++i)
  {
    printf("%g ", dArray[i]);
  }
  printf("\n");
}

void
test_saveP6(const char *inputFileName,
            const char *outputFileName)
{
  printf("\n~~~~ %s(%s, %s) ~~~~\n", __func__, inputFileName, outputFileName);
  int width, height;
  uint8_t *contents=Netpbm_loadP3(inputFileName, &width, &height);
  if(contents==NULL)
  {
    fprintf(stderr, "cannot load %s\n", inputFileName);
    return;
  }
  printf("width=%d height=%d\n", width, height);
  int byteCount=3*width*height;
  for(int i=0; i<byteCount; i+=3)
  {
    uint8_t red=contents[i+0], green=contents[i+1], blue=contents[i+2];
    contents[i+0]=green;
    contents[i+1]=blue;
    contents[i+2]=red;
  }
  if(!Netpbm_saveP6(outputFileName, width, height, contents))
  {
    fprintf(stderr, "cannot save %s\n", outputFileName);
  }
  free(contents);
}

void
test_loadP6(const char *inputFileName,
            const char *outputFileName)
{
  printf("\n~~~~ %s(%s, %s) ~~~~\n", __func__, inputFileName, outputFileName);
  int width, height;
  uint8_t *contents=Netpbm_loadP6(inputFileName, &width, &height);
  if(contents==NULL)
  {
    fprintf(stderr, "cannot load %s\n", inputFileName);
    return;
  }
  printf("width=%d height=%d\n", width, height);
  int byteCount=3*width*height;
  for(int i=0; i<byteCount; i+=3)
  {
    uint8_t red=contents[i+0], green=contents[i+1], blue=contents[i+2];
    contents[i+0]=blue;
    contents[i+1]=red;
    contents[i+2]=green;
  }
  if(!Netpbm_saveP6(outputFileName, width, height, contents))
  {
    fprintf(stderr, "cannot save %s\n", outputFileName);
  }
  free(contents);
}

int
main(int argc,
     char **argv)
{
  if(argc<2)
  {
    fprintf(stderr, "usage: %s test_numbers...\n", argv[0]);
    return 1;
  }
  for(int i=1; i<argc; ++i)
  {
    int minTest=1, maxTest=10;
    if(strcmp(argv[i], "all")!=0)
    {
      if(sscanf(argv[i], "%d", &minTest)==1)
      {
        maxTest=minTest;
      }
      else
      {
        fprintf(stderr, "ignoring %s\n", argv[i]);
        continue;
      }
    }
    for(int test=minTest; test<=maxTest; ++test)
    {
      printf("\n#### test %d ####", test);
      switch(test)
      {
        case 1:
        {
          test_output("this is a sentence");
          break;
        }
        case 2:
        {
          test_txtWrite("output_text.txt");
          break;
        }
        case 3:
        {
          test_txtWrite("/output_forbidden.txt");
          break;
        }
        case 4:
        {
          test_saveP3("output_A.ppm", 320, 200);
          break;
        }
        case 5:
        {
          test_input();
          break;
        }
        case 6:
        {
          test_loadP3("output_A.ppm", "output_C.ppm");
          break;
        }
        case 7:
        {
          test_binWrite("output_data.bin");
          break;
        }
        case 8:
        {
          test_binRead("output_data.bin");
          break;
        }
        case 9:
        {
          test_saveP6("output_A.ppm", "output_D.ppm");
          break;
        }
        case 10:
        {
          test_loadP6("output_D.ppm", "output_E.ppm");
          break;
        }
        default:
        {
          fprintf(stderr, "unexpected test number %d\n", test);
          break;
        }
      }
    }
  }
  return 0;
}

//----------------------------------------------------------------------------