#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

static void pbm(char *front, size_t stride) {
    printf("P1\n%lu %lu\n", stride, stride);

    for (size_t i = 0; i < stride * stride; i++) {
        putchar(front[i] ? '1' : '0');
    }
}

int main(int argc, char **argv) {
    int vis = 0, opt;
    long long maxiter = 50;

    while ((opt = getopt(argc, argv, "vi:")) != -1) {
        switch (opt) {
        case 'v':
            vis = 1;
            break;
        case 'i':
            maxiter = atoll(optarg);
            break;
        default:
usage:
            fprintf(stderr, "Usage: %s [-v] [-i iterations] input\n\n"
                            "-v output is NetPBM, readable by FFmpeg\n",
                    argv[0]);
            return 1;
        }
    }

    if (optind >= argc)
        goto usage;

    char *algo = NULL, *front = NULL, *back = NULL, *s;
    size_t stride = 0, S = 0, G = 0;

    FILE *fp = fopen(argv[optind], "r");
    if(!fp) {
        fprintf(stderr, "%s: Could not open file '%s': ",
                argv[0], argv[optind]);
        perror("");

        return 1;
    }


    fscanf(fp, "%ms", &algo);
    for (char *ap=algo; *ap; ap++)
        *ap = *ap == '#';

    while (fscanf(fp, "%ms\n", &s) == 1) {
        size_t len = strlen(s);
        char *dst;

        if (!stride) {
            stride = len * 3;
            front = calloc(stride * stride, 1);
            dst = front + stride * len;
        }

        dst += len;
        for (size_t c = 0; c < len; c++)
            *dst++ = s[c] == '#';
        dst += len;

        free(s);
    }

    fclose(fp);

    back = malloc(stride * stride);
    memcpy(back, front, stride * stride);

    for (long long iter = 0; iter < maxiter; iter++) {
        if (vis && iter & 1) pbm(front, stride);

        if (iter == 2) {
            for (int p = 0; p < stride * stride; p++)
                S += front[p];
        }

        #pragma omp parallel for
        for (size_t y = 0; y < stride; y++) {
            for (size_t x = 0; x < stride; x++) {
                int v = 0;

                for (int yy = -1; yy <= 1; yy++) {
                    for (int xx = -1; xx <= 1; xx++) {
                        v <<= 1;

                        if (y + yy > 0 && y + yy < stride &&
                            x + xx > 0 && x + xx < stride)
                            v |= front[(y + yy) * stride + x + xx];
                        else
                            v |= iter & 1;

                        back[y * stride + x] = algo[v];
                    }
                }
            }
        }

        char *tmp=front;
        front=back;
        back=tmp;
    }

    for (size_t p = 0; p < stride * stride; p++)
        G += front[p];

    fprintf(stderr, "Silver: %lu\nGold: %lu\n", S, G);

    free(front);
    free(algo);
    free(back);
}