// Basic fuzz test for depcapsulate operation,

#include <stddef.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <err.h>

extern "C" {

#include "crypto_api.h"
#include "hash.c"

#undef randombytes
#define USE_SNTRUP761X25519 1
#ifdef SNTRUP761_NO_ASM
# undef __GNUC__
#endif
void randombytes(unsigned char *ptr, size_t l);
volatile crypto_int16 crypto_int16_optblocker = 0;
volatile crypto_int32 crypto_int32_optblocker = 0;
volatile crypto_int64 crypto_int64_optblocker = 0;
#include "sntrup761.c"

static int real_random;

void
randombytes(unsigned char *ptr, size_t l)
{
        if (real_random)
                arc4random_buf(ptr, l);
        else
                memset(ptr, 0, l);
}

void privkeys(unsigned char *zero_sk, unsigned char *rnd_sk)
{
        unsigned char pk[crypto_kem_sntrup761_PUBLICKEYBYTES];

        real_random = 0;
        if (crypto_kem_sntrup761_keypair(pk, zero_sk) != 0)
                errx(1, "crypto_kem_sntrup761_keypair failed");
        real_random = 1;
        if (crypto_kem_sntrup761_keypair(pk, rnd_sk) != 0)
                errx(1, "crypto_kem_sntrup761_keypair failed");
}

int LLVMFuzzerTestOneInput(const uint8_t* input, size_t len)
{
        static bool once;
        static unsigned char zero_sk[crypto_kem_sntrup761_SECRETKEYBYTES];
        static unsigned char rnd_sk[crypto_kem_sntrup761_SECRETKEYBYTES];
        unsigned char ciphertext[crypto_kem_sntrup761_CIPHERTEXTBYTES];
        unsigned char secret[crypto_kem_sntrup761_BYTES];

        if (!once) {
                privkeys(zero_sk, rnd_sk);
                once = true;
        }

        memset(&ciphertext, 0, sizeof(ciphertext));
        if (len > sizeof(ciphertext)) {
                len = sizeof(ciphertext);
        }
        memcpy(ciphertext, input, len);

        (void)crypto_kem_sntrup761_dec(secret, ciphertext, zero_sk);
        (void)crypto_kem_sntrup761_dec(secret, ciphertext, rnd_sk);
        return 0;
}

} // extern