#include "include.h"
#include "ppm.h"

int LoadPpmFile(char *filename, PpmImage *ppm)
{
    FILE *stream;
    char str[256];
    int width, height, maxval;
    unsigned int size;

    if (!(stream = fopen(filename, "rb"))) {
	printf("couldn't open file %s\n", filename);
	return 0;
    }

    fgets(str, 256, stream);
    if (strncmp(str, "P6", 2) && strncmp(str, "P3", 2)) {
	fclose(stream);
	printf("bad magic number %s\n", str);
	return 0;
    }

    do {
	fgets(str, 256, stream);
    } while (str[0] == '#'); // skip the comments

    if (sscanf(str, "%d %d", &width, &height) != 2) {
	fclose(stream);
	printf("couldn't figure out the size of image %s\n", filename);
	return 0;
    }

    fgets(str, 256, stream);
    if (sscanf(str, "%d", &maxval) != 1) {
	fclose(stream);
	printf("couldn't read maxval of image %s\n", filename);
	return 0;
    }
    if (maxval != 255) {
	printf("warning: maxval == %d, not 255\n", maxval);
    }

    size = 3*width*height;
    if (!(ppm->data = new unsigned char[size])) {
	fclose(stream);
	printf("couldn't allocated memory for the image pixels\n");
	return -1;
    }
    if (fread(ppm->data, sizeof(unsigned char), size, stream) != size) {
	fclose(stream);
	printf("couldn't read the image data for %s\n", filename);
	return 0;
    }

    ppm->width = width;
    ppm->height = height;

    if (fclose(stream)) {
	return 0;
    }

    return 1;
}