#include <stdint.h>
#include <stdbool.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include "miner.h"

typedef uint32_t word32;

static word32 rotrFixed(word32 word, unsigned int shift)
{
	return (word >> shift) | (word << (32 - shift));
}

#define blk0(i) (W[i] = data[i])

static const word32 SHA256_K[64] = {
	0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,
	0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
	0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
	0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
	0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,
	0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
	0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,
	0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
	0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
	0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
	0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,
	0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
	0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5,
	0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
	0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
	0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
};

#define blk2(i) (W[i&15]+=s1(W[(i-2)&15])+W[(i-7)&15]+s0(W[(i-15)&15]))

#define Ch(x,y,z) (z^(x&(y^z)))
#define Maj(x,y,z) (y^((x^y)&(y^z)))

#define a(i) T[(0-i)&7]
#define b(i) T[(1-i)&7]
#define c(i) T[(2-i)&7]
#define d(i) T[(3-i)&7]
#define e(i) T[(4-i)&7]
#define f(i) T[(5-i)&7]
#define g(i) T[(6-i)&7]
#define h(i) T[(7-i)&7]

#define R(i) h(i)+=S1(e(i))+Ch(e(i),f(i),g(i))+SHA256_K[i+j]+(j?blk2(i):blk0(i));\
	d(i)+=h(i);h(i)+=S0(a(i))+Maj(a(i),b(i),c(i))

// for SHA256
#define S0(x) (rotrFixed(x,2)^rotrFixed(x,13)^rotrFixed(x,22))
#define S1(x) (rotrFixed(x,6)^rotrFixed(x,11)^rotrFixed(x,25))
#define s0(x) (rotrFixed(x,7)^rotrFixed(x,18)^(x>>3))
#define s1(x) (rotrFixed(x,17)^rotrFixed(x,19)^(x>>10))

static void SHA256_Transform(word32 *state, const word32 *data)
{
	word32 W[16];
	word32 T[8];
	unsigned int j;

    /* Copy context->state[] to working vars */
	memcpy(T, state, sizeof(T));
    /* 64 operations, partially loop unrolled */
	for (j=0; j<64; j+=16)
	{
		R( 0); R( 1); R( 2); R( 3);
		R( 4); R( 5); R( 6); R( 7);
		R( 8); R( 9); R(10); R(11);
		R(12); R(13); R(14); R(15);
	}
    /* Add the working vars back into context.state[] */
    state[0] += a(0);
    state[1] += b(0);
    state[2] += c(0);
    state[3] += d(0);
    state[4] += e(0);
    state[5] += f(0);
    state[6] += g(0);
    state[7] += h(0);
}

static void runhash(void *state, const void *input, const void *init)
{
	memcpy(state, init, 32);
	SHA256_Transform(state, input);
}

/* suspiciously similar to ScanHash* from bitcoin */
bool scanhash_cryptopp(const unsigned char *midstate, unsigned char *data,
	        unsigned char *hash1, unsigned char *hash,
	        unsigned long *hashes_done)
{
	uint32_t *hash32 = (uint32_t *) hash;
	uint32_t *nonce = (uint32_t *)(data + 12);
	uint32_t n = 0;
	unsigned long stat_ctr = 0;

	while (1) {
		n++;
		*nonce = n;

		runhash(hash1, data, midstate);
		runhash(hash, hash1, sha256_init_state);

		stat_ctr++;

		if (hash32[7] == 0) {
			char *hexstr;

			hexstr = bin2hex(hash, 32);
			fprintf(stderr,
				"DBG: found zeroes in hash:\n%s\n",
				hexstr);
			free(hexstr);

			*hashes_done = stat_ctr;
			return true;
		}

		if ((n & 0xffffff) == 0) {
			if (opt_debug)
				fprintf(stderr, "DBG: end of nonce range\n");
			*hashes_done = stat_ctr;
			return false;
		}
	}
}