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

#define FILE_HEADER_STRING "__info2_image_file_format__"
// define BUFFER 100
// 10x10 pixel

/* ----------------------------------------------------------
   1. Header prüfen
   ---------------------------------------------------------- */
static int readHeader(FILE *file) {
  char header[sizeof(FILE_HEADER_STRING)];
  if (fread(header, 1, sizeof(FILE_HEADER_STRING) - 1, file) !=
      sizeof(FILE_HEADER_STRING) - 1)
    return 0;
  header[sizeof(FILE_HEADER_STRING) - 1] = '\0';
  return strcmp(header, FILE_HEADER_STRING) == 0;
}

/* ----------------------------------------------------------
   2. Meta-Daten lesen (unsigned short)
   ---------------------------------------------------------- */
static int readMeta(FILE *file, unsigned short *count, unsigned short *width,
                    unsigned short *height) {
  if (fread(count, sizeof(unsigned short), 1, file) != 1)
    return 0;
  if (fread(width, sizeof(unsigned short), 1, file) != 1)
    return 0;
  if (fread(height, sizeof(unsigned short), 1, file) != 1)
    return 0;

  return 1;
}

/* ----------------------------------------------------------
   3. Einzelbild lesen
   ---------------------------------------------------------- */
static int readSingleImage(FILE *file, GrayScaleImage *img,
                           unsigned short width, unsigned short height) {
  img->width = width;
  img->height = height;

  size_t numPixels = (size_t)width * (size_t)height; // anzahl an pixeln
  img->buffer = malloc(numPixels);
  if (!img->buffer)
    return 0;

  if (fread(img->buffer, 1, numPixels, file) != numPixels) {
    free(img->buffer);
    img->buffer = NULL; // fehler bei ungültiger eingabe
    return 0;
  }
  return 1;
}

/* ----------------------------------------------------------
   4. Label lesen
   ---------------------------------------------------------- */
static int readLabel(FILE *file, unsigned char *label) {
  return fread(label, 1, 1, file) == 1;
}

/* ----------------------------------------------------------
   5. Komplette Bildserie lesen
   ---------------------------------------------------------- */
GrayScaleImageSeries *readImages(const char *path) {
  FILE *file = fopen(path, "rb");
  if (!file)
    return NULL;

  if (!readHeader(file)) {
    fclose(file);
    return NULL;
  }

  unsigned short count, width, height;
  if (!readMeta(file, &count, &width, &height)) {

    fclose(file);
    return NULL;
  }
  // printf("%d, %d, %d", count, width, height);

  GrayScaleImageSeries *series = malloc(sizeof(GrayScaleImageSeries));
  if (!series) {
    fclose(file);
    return NULL;
  }

  series->count = count;
  series->images = malloc(count * sizeof(GrayScaleImage));
  series->labels = malloc(count * sizeof(unsigned char));
  if (!series->images || !series->labels) {
    free(series->images);
    free(series->labels);
    free(series);
    fclose(file);
    return NULL;
  }

  for (unsigned int i = 0; i < count; i++) {
    if (!readSingleImage(file, &series->images[i], width, height) ||
        !readLabel(file, &series->labels[i])) {
      // Aufräumen bei Fehler
      for (unsigned int j = 0; j < i; j++) {
        free(series->images[j].buffer);
      }
      free(series->images);
      free(series->labels);
      free(series);
      fclose(file);
      return NULL;
    }
  }

  fclose(file);
  return series;
}

/* ----------------------------------------------------------
   6. Speicher komplett freigeben
   ---------------------------------------------------------- */
void clearSeries(GrayScaleImageSeries *series) {
  if (!series)
    return;

  for (unsigned int i = 0; i < series->count; i++) {
    free(series->images[i].buffer);
  }

  free(series->images);
  free(series->labels);
  free(series);
}