/* test harness: decode a .webp to RGBA, report, dump a PPM for eyeballing */
#include <stdio.h>
#include <stdlib.h>

#define WEBPDEC_IMPLEMENTATION
#include "webpdec.h"

int main(int argc, char **argv) {
  if (argc < 2) { fprintf(stderr, "usage: %s file.webp [out.ppm]\n", argv[0]); return 2; }
  FILE *f = fopen(argv[1], "rb");
  if (!f) { perror("open"); return 1; }
  fseek(f, 0, SEEK_END); long n = ftell(f); fseek(f, 0, SEEK_SET);
  unsigned char *buf = malloc(n);
  if (fread(buf, 1, n, f) != (size_t)n) { perror("read"); return 1; }
  fclose(f);

  int w = 0, h = 0;
  if (!WebPGetInfo(buf, n, &w, &h)) { fprintf(stderr, "not a webp / bad header\n"); return 1; }
  printf("WebPGetInfo: %dx%d\n", w, h);

  uint8_t *rgba = WebPDecodeRGBA(buf, n, &w, &h);
  if (!rgba) { fprintf(stderr, "decode FAILED\n"); return 1; }
  printf("decoded: %dx%d, RGBA (R,G,B,A top-to-bottom)\n", w, h);

  /* sample a few pixels */
  long center = ((long)h/2 * w + w/2) * 4;
  printf("center px RGBA = %d %d %d %d\n",
         rgba[center], rgba[center+1], rgba[center+2], rgba[center+3]);

  /* checksum + alpha presence */
  unsigned long sum = 0; int has_alpha = 0;
  for (long i = 0; i < (long)w*h; i++) {
    sum += rgba[i*4] + rgba[i*4+1] + rgba[i*4+2];
    if (rgba[i*4+3] != 255) has_alpha = 1;
  }
  printf("rgb checksum=%lu  non-opaque-alpha=%s\n", sum, has_alpha ? "yes" : "no");

  if (argc >= 3) {  /* .raw => raw RGBA dump; else opaque PPM */
    const char *p = argv[2];
    size_t L = 0; while (p[L]) L++;
    FILE *o = fopen(argv[2], "wb");
    if (L >= 4 && p[L-4]=='.' && p[L-3]=='r' && p[L-2]=='a' && p[L-1]=='w') {
      fwrite(rgba, 4, (size_t)w*h, o);
    } else {
      fprintf(o, "P6\n%d %d\n255\n", w, h);
      for (long i = 0; i < (long)w*h; i++) fwrite(&rgba[i*4], 1, 3, o);
    }
    fclose(o);
    printf("wrote %s\n", argv[2]);
  }
  WebPFree(rgba);
  free(buf);
  return 0;
}