#include "algo-gate-api.h"

#include <string.h>
#include <stdint.h>

#include "sph-blake2s.h"

static __thread blake2s_state s_midstate;
static __thread blake2s_state s_ctx;
#define MIDLEN 76

void blake2s_hash(void *output, const void *input)
{
	unsigned char _ALIGN(64) hash[BLAKE2S_OUTBYTES];
	blake2s_state blake2_ctx __attribute__ ((aligned (64)));

	blake2s_init(&blake2_ctx, BLAKE2S_OUTBYTES);
	blake2s_update(&blake2_ctx, input, 80);
	blake2s_final(&blake2_ctx, hash, BLAKE2S_OUTBYTES);

	memcpy(output, hash, 32);
}

static void blake2s_hash_end(uint32_t *output, const uint32_t *input)
{
	s_ctx.buflen = MIDLEN;
	memcpy(&s_ctx, &s_midstate, 32 + 16 + MIDLEN);
	blake2s_update(&s_ctx, (uint8_t*) &input[MIDLEN/4], 80 - MIDLEN);
	blake2s_final(&s_ctx, (uint8_t*) output, BLAKE2S_OUTBYTES);
}

int scanhash_blake2s(int thr_id, struct work *work,
	uint32_t max_nonce, uint64_t *hashes_done)
{
        uint32_t *pdata = work->data;
        uint32_t *ptarget = work->target;

	uint32_t _ALIGN(64) hash64[8];
	uint32_t _ALIGN(64) endiandata[20];

	const uint32_t Htarg = ptarget[7];
	const uint32_t first_nonce = pdata[19];

	uint32_t n = first_nonce;

        swab32_array( endiandata, pdata, 20 );

	// midstate
	blake2s_init(&s_midstate, BLAKE2S_OUTBYTES);
	blake2s_update(&s_midstate, (uint8_t*) endiandata, MIDLEN);
	memcpy(&s_ctx, &s_midstate, sizeof(blake2s_state));

	do {
		be32enc(&endiandata[19], n);
		blake2s_hash_end(hash64, endiandata);
		if (hash64[7] < Htarg && fulltest(hash64, ptarget)) {
			*hashes_done = n - first_nonce + 1;
			pdata[19] = n;
			return true;
		}
		n++;

	} while (n < max_nonce && !work_restart[thr_id].restart);

	*hashes_done = n - first_nonce + 1;
	pdata[19] = n;

	return 0;
}

// changed to get_max64_0x3fffffLL in cpuminer-multi-decred
int64_t blake2s_get_max64 ()
{
   return 0x7ffffLL;
}

bool register_blake2s_algo( algo_gate_t* gate )
{
  gate->scanhash  = (void*)&scanhash_blake2s;
  gate->hash      = (void*)&blake2s_hash;
  gate->get_max64 = (void*)&blake2s_get_max64;
  return true;
};