/* TODO: build system
 * gcc -std=gnu99 -W -Wall -Werror -O3 main.c mpz.c -o pszip -lgmp -lcrypto */

#include <openssl/sha.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "mpz.h"

/* Hash is currently downgraded to SHA1 for now, as it is faster and there is
 * not yet a reason for anything stronger. */
#define HASH_LENGTH SHA_DIGEST_LENGTH
static void hash_mpz(void *output, const mpz_t n, size_t size)
{
    SHA1((void *)mpz_limbs_read(n), size, output);
}

int main(int argc, char **argv)
{
    unsigned char original_hash[HASH_LENGTH];
    unsigned char iteration_hash[HASH_LENGTH];
    struct pszip_mpz_state mpzs;
    mpz_t original;

    if (argc < 2)
    {
        fprintf(stderr, "Usage:  %s <string>\n", argv[0]);
        return 1;
    }

    /* Process original data */
    size_t size = strlen(argv[1]);
    pszip_mpz_init_data(original, argv[1], size);
    mp_bitcnt_t popcnt = mpz_popcount(original);
    hash_mpz(original_hash, original, size);
    mpz_clear(original);

    /* Display metadata */
    printf("%s\n", argv[1]);
    for (int i = 0; i < HASH_LENGTH; i++)
        printf("%02x", original_hash[i]);
    printf("\nsize = %zu\n", size);
    printf("popcnt = %llu\n", (long long unsigned)popcnt);

    /* Search for solution (1 thread) */
    pszip_mpz_state_init(&mpzs, popcnt, size);

    while (1)
    {
        hash_mpz(iteration_hash, mpzs.current, size);
        if (memcmp(iteration_hash, original_hash, HASH_LENGTH) == 0)
            break;
        pszip_mpz_iterate_bithack01(&mpzs);
    }

    /* Results */
    printf("\nFound!\n");
    fwrite(mpz_limbs_read(mpzs.current), 1, size, stdout);
    printf("\n");

    pszip_mpz_state_clear(&mpzs);
    return 0;
}