#include <string.h>
#include <openssl/sha.h>
#include <stdint.h>

#include "algo-gate-api.h"
#include "sph_hefty1.h"
#include "algo/keccak/sph_keccak.h"
#include "algo/blake/sph_blake.h"
#include "algo/groestl/sph_groestl.h"

/* Combines top 64-bits from each hash into a single hash */
static void combine_hashes(uint32_t *out, uint32_t *hash1, uint32_t *hash2, uint32_t *hash3, uint32_t *hash4)
{
    uint32_t *hash[4] = { hash1, hash2, hash3, hash4 };

    /* Transpose first 64 bits of each hash into out */
    memset(out, 0, 32);
    int bits = 0;
    for (unsigned int i = 7; i >= 6; i--) {
        for (uint32_t mask = 0x80000000; mask; mask >>= 1) {
            for (unsigned int k = 0; k < 4; k++) {
                out[(255 - bits)/32] <<= 1;
                if ((hash[k][i] & mask) != 0)
                    out[(255 - bits)/32] |= 1;
                bits++;
            }
        }
    }
}

extern void heavyhash(unsigned char* output, const unsigned char* input, int len)
{
    unsigned char hash1[32];
    HEFTY1(input, len, hash1);

// HEFTY1 is new, so take an extra security measure to eliminate
//     * the possiblity of collisions:
//     *
//     *     Hash(x) = SHA256(x + HEFTY1(x))
//     *
//     * N.B. '+' is concatenation.
//
    unsigned char hash2[32];;
    SHA256_CTX ctx;
    SHA256_Init(&ctx);
    SHA256_Update(&ctx, input, len);
    SHA256_Update(&ctx, hash1, sizeof(hash1));
    SHA256_Final(hash2, &ctx);

//   * Additional security: Do not rely on a single cryptographic hash
//     * function.  Instead, combine the outputs of 4 of the most secure
//     * cryptographic hash functions-- SHA256, KECCAK512, GROESTL512
//     * and BLAKE512.


    uint32_t hash3[16];
    sph_keccak512_context keccakCtx;
    sph_keccak512_init(&keccakCtx);
    sph_keccak512(&keccakCtx, input, len);
    sph_keccak512(&keccakCtx, hash1, sizeof(hash1));
    sph_keccak512_close(&keccakCtx, (void *)&hash3);

    uint32_t hash4[16];
    sph_groestl512_context groestlCtx;
    sph_groestl512_init(&groestlCtx);
    sph_groestl512(&groestlCtx, input, len);
    sph_groestl512(&groestlCtx, hash1, sizeof(hash1));
    sph_groestl512_close(&groestlCtx, (void *)&hash4);

    uint32_t hash5[16];
    sph_blake512_context blakeCtx;
    sph_blake512_init(&blakeCtx);
    sph_blake512(&blakeCtx, input, len);
    sph_blake512(&blakeCtx, (unsigned char *)&hash1, sizeof(hash1));
    sph_blake512_close(&blakeCtx, (void *)&hash5);

    uint32_t *final = (uint32_t *)output;
    combine_hashes(final, (uint32_t *)hash2, hash3, hash4, hash5);

}

int scanhash_heavy( uint32_t *pdata, const uint32_t *ptarget,
            uint32_t max_nonce, uint64_t *hashes_done, struct thr_info *mythr)
{
    uint32_t hash[8];
    uint32_t start_nonce = pdata[19];
    int thr_id = mythr->id;  // thr_id arg is deprecated
    
    do {
        heavyhash((unsigned char *)hash, (unsigned char *)pdata, 80);
    
        if (hash[7] <= ptarget[7]) {
            if (fulltest(hash, ptarget)) {
                *hashes_done = pdata[19] - start_nonce;
                return 1;
                break;
            }
        }
        pdata[19]++;
    } while (pdata[19] < max_nonce && !work_restart[thr_id].restart);
    *hashes_done = pdata[19] - start_nonce;
    return 0;
}

bool register_heavy_algo( algo_gate_t* gate )
{
    gate->scanhash = (void*)&scanhash_heavy;
    gate->hash     = (void*)&heavyhash;
    return true;
};