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

PPM *ppm_alloc(int r, int c) {
  PPM *img;

  img = (PPM *)malloc(sizeof(PPM));
  img->ptype = 6;
  img->w = c;
  img->h = r;
  img->bpp = 3;
  img->max = 255;
  img->name = NULL;

  img->rpix = (float *)malloc(r * c * sizeof(float));
  img->gpix = (float *)malloc(r * c * sizeof(float));
  img->bpix = (float *)malloc(r * c * sizeof(float));

  if (!(img->rpix = (float *)malloc(r * c * sizeof(float)))) {
    fprintf(stderr, "out of memory\n");
    return NULL;
  }

  if (!(img->gpix = (float *)malloc(r * c * sizeof(float)))) {
    fprintf(stderr, "out of memory\n");
    return NULL;
  }

  if (!(img->bpix = (float *)malloc(r * c * sizeof(float)))) {
    fprintf(stderr, "out of memory\n");
    return NULL;
  }

  return img;
}

void ppm_free(PPM **img) {
  if ((*img)) {

    if ((*img)->name)
      free((*img)->name);
    if ((*img)->rpix)
      free((*img)->rpix);
    if ((*img)->gpix)
      free((*img)->gpix);
    if ((*img)->bpix)
      free((*img)->bpix);

    free(*img);
  }

  (*img) = NULL;
}

PPM *ppm_read(const char *file) {
  int rows = 0, cols = 0, ptype, max;
  unsigned char byte;
  PPM *img;
  FILE *fp;

  if(!(fp = fopen(file, "r"))) {
      fprintf(stderr, "couldn't open file\n");
      return(NULL);
  }

  fscanf(fp, "P%d\n", &ptype);
  fscanf(fp, "%d %d\n", &cols, &rows);
  fscanf(fp, "%d\n", &max);

  if (!(img = ppm_alloc(rows, cols))) {
    fprintf(stderr, "couldn't allocate image\n");
    return (NULL);
  }

  img->h = rows;
  img->w = cols;
  img->max = max;
  img->ptype = ptype;


  for (int i = 0; i < cols; ++i) {
    for (int j = 0; j < rows; ++j) {
      fread(&byte, sizeof(unsigned char), 1, fp);
      img->rpix[i * cols + j] = (float)byte / (float)img->max;
      img->gpix[i * cols + j] = (float)byte / (float)img->max;
      img->bpix[i * cols + j] = (float)byte / (float)img->max;
    }
  }

    fclose(fp);
  return (img);
}

void ppm_write(PPM *img, const char *file) {
  int rows = img->h, cols = img->w;
  FILE *fp = fopen(file, "w");
  unsigned char byte;

  fprintf(fp, "P%d\n", img->ptype);
  fprintf(fp, "#made by Lemuel Reid\n");
  fprintf(fp, "%d %d\n", img->w, img->h);
  fprintf(fp, "%d\n", img->max);

  // write pixels
  for (int i = 0; i < rows; i++) {
    for (int j = 0; j < cols; ++j) {
      byte = (unsigned char)(img->rpix[i * img->w + j] * (float)img->max);
      byte = (unsigned char)(img->gpix[i * img->w + j] * (float)img->max);
      byte = (unsigned char)(img->bpix[i * img->w + j] * (float)img->max);
      fwrite(&byte, sizeof(unsigned char), 1, fp);
    }
  }

  fclose(fp);
}