// buffer_example.cpp
#include <nan.h>
using namespace Nan;  
using namespace v8;

static void add(int x) {
    printf("input %d\n", x);
}

typedef struct SHA256Context {
	uint32_t state[8];
	uint32_t buf[16];
} SHA256_CTX;


uint16_t swab16(uint16_t value) {
  return ((((value) & 0xff) << 8) | ((value) >> 8));
}

uint32_t swab32(uint32_t value) {
  return (((uint32_t)swab16((uint16_t)((value) & 0xffff)) << 16) |\
    (uint32_t)swab16((uint16_t)((value) >> 16)));
}
void swap32yes(void*out, const void*in, size_t sz) {
        size_t swapcounter = 0;
        for (swapcounter = 0; swapcounter < sz; ++swapcounter)
                (((uint32_t*)out)[swapcounter]) = swab32(((uint32_t*)in)[swapcounter]);
}

#define swap32tole(out, in, sz) ((out == in) ? (void)0 : (void)memmove(out, in, (sz)*4))
#define swap32tobe(out, in, sz)  swap32yes(out, in, sz)
/*
 * Encode a length len/4 vector of (uint32_t) into a length len vector of
 * (unsigned char) in big-endian form.  Assumes len is a multiple of 4.
 */

static inline void
be32enc_vect(uint32_t *dst, const uint32_t *src, uint32_t len)
{
	uint32_t i;

	for (i = 0; i < len; i++)
		dst[i] = swab32(src[i]);
}

/* Elementary functions used by SHA256 */
#define Ch(x, y, z)	((x & (y ^ z)) ^ z)
#define Maj(x, y, z)	((x & (y | z)) | (y & z))
#define SHR(x, n)	(x >> n)
#define ROTR(x, n)	((x >> n) | (x << (32 - n)))
#define S0(x)		(ROTR(x, 2) ^ ROTR(x, 13) ^ ROTR(x, 22))
#define S1(x)		(ROTR(x, 6) ^ ROTR(x, 11) ^ ROTR(x, 25))
#define s0(x)		(ROTR(x, 7) ^ ROTR(x, 18) ^ SHR(x, 3))
#define s1(x)		(ROTR(x, 17) ^ ROTR(x, 19) ^ SHR(x, 10))

/* SHA256 round function */
#define RND(a, b, c, d, e, f, g, h, k)			\
	t0 = h + S1(e) + Ch(e, f, g) + k;		\
	t1 = S0(a) + Maj(a, b, c);			\
	d += t0;					\
	h  = t0 + t1;

/* Adjusted round function for rotating state */
#define RNDr(S, W, i, k)			\
	RND(S[(64 - i) % 8], S[(65 - i) % 8],	\
	    S[(66 - i) % 8], S[(67 - i) % 8],	\
	    S[(68 - i) % 8], S[(69 - i) % 8],	\
	    S[(70 - i) % 8], S[(71 - i) % 8],	\
	    W[i] + k)

/*
 * SHA256 block compression function.  The 256-bit state is transformed via
 * the 512-bit input block to produce a new state.
 */
static void
SHA256_Transform(uint32_t * state, const uint32_t block[16], int swap)
{
	uint32_t W[64];
	uint32_t S[8];
	uint32_t t0, t1;
	int i;

	/* 1. Prepare message schedule W. */
	if(swap)
		for (i = 0; i < 16; i++)
			W[i] = swab32(block[i]);
	else
		memcpy(W, block, 64);
	for (i = 16; i < 64; i += 2) {
		W[i] = s1(W[i - 2]) + W[i - 7] + s0(W[i - 15]) + W[i - 16];
		W[i+1] = s1(W[i - 1]) + W[i - 6] + s0(W[i - 14]) + W[i - 15];
	}

	/* 2. Initialize working variables. */
	memcpy(S, state, 32);

	/* 3. Mix. */
	RNDr(S, W, 0, 0x428a2f98);
	RNDr(S, W, 1, 0x71374491);
	RNDr(S, W, 2, 0xb5c0fbcf);
	RNDr(S, W, 3, 0xe9b5dba5);
	RNDr(S, W, 4, 0x3956c25b);
	RNDr(S, W, 5, 0x59f111f1);
	RNDr(S, W, 6, 0x923f82a4);
	RNDr(S, W, 7, 0xab1c5ed5);
	RNDr(S, W, 8, 0xd807aa98);
	RNDr(S, W, 9, 0x12835b01);
	RNDr(S, W, 10, 0x243185be);
	RNDr(S, W, 11, 0x550c7dc3);
	RNDr(S, W, 12, 0x72be5d74);
	RNDr(S, W, 13, 0x80deb1fe);
	RNDr(S, W, 14, 0x9bdc06a7);
	RNDr(S, W, 15, 0xc19bf174);
	RNDr(S, W, 16, 0xe49b69c1);
	RNDr(S, W, 17, 0xefbe4786);
	RNDr(S, W, 18, 0x0fc19dc6);
	RNDr(S, W, 19, 0x240ca1cc);
	RNDr(S, W, 20, 0x2de92c6f);
	RNDr(S, W, 21, 0x4a7484aa);
	RNDr(S, W, 22, 0x5cb0a9dc);
	RNDr(S, W, 23, 0x76f988da);
	RNDr(S, W, 24, 0x983e5152);
	RNDr(S, W, 25, 0xa831c66d);
	RNDr(S, W, 26, 0xb00327c8);
	RNDr(S, W, 27, 0xbf597fc7);
	RNDr(S, W, 28, 0xc6e00bf3);
	RNDr(S, W, 29, 0xd5a79147);
	RNDr(S, W, 30, 0x06ca6351);
	RNDr(S, W, 31, 0x14292967);
	RNDr(S, W, 32, 0x27b70a85);
	RNDr(S, W, 33, 0x2e1b2138);
	RNDr(S, W, 34, 0x4d2c6dfc);
	RNDr(S, W, 35, 0x53380d13);
	RNDr(S, W, 36, 0x650a7354);
	RNDr(S, W, 37, 0x766a0abb);
	RNDr(S, W, 38, 0x81c2c92e);
	RNDr(S, W, 39, 0x92722c85);
	RNDr(S, W, 40, 0xa2bfe8a1);
	RNDr(S, W, 41, 0xa81a664b);
	RNDr(S, W, 42, 0xc24b8b70);
	RNDr(S, W, 43, 0xc76c51a3);
	RNDr(S, W, 44, 0xd192e819);
	RNDr(S, W, 45, 0xd6990624);
	RNDr(S, W, 46, 0xf40e3585);
	RNDr(S, W, 47, 0x106aa070);
	RNDr(S, W, 48, 0x19a4c116);
	RNDr(S, W, 49, 0x1e376c08);
	RNDr(S, W, 50, 0x2748774c);
	RNDr(S, W, 51, 0x34b0bcb5);
	RNDr(S, W, 52, 0x391c0cb3);
	RNDr(S, W, 53, 0x4ed8aa4a);
	RNDr(S, W, 54, 0x5b9cca4f);
	RNDr(S, W, 55, 0x682e6ff3);
	RNDr(S, W, 56, 0x748f82ee);
	RNDr(S, W, 57, 0x78a5636f);
	RNDr(S, W, 58, 0x84c87814);
	RNDr(S, W, 59, 0x8cc70208);
	RNDr(S, W, 60, 0x90befffa);
	RNDr(S, W, 61, 0xa4506ceb);
	RNDr(S, W, 62, 0xbef9a3f7);
	RNDr(S, W, 63, 0xc67178f2);

	/* 4. Mix local working variables into global state */
	for (i = 0; i < 8; i++)
		state[i] += S[i];
}

static inline void
SHA256_InitState(uint32_t * state)
{
	/* Magic initialization constants */
	state[0] = 0x6A09E667;
	state[1] = 0xBB67AE85;
	state[2] = 0x3C6EF372;
	state[3] = 0xA54FF53A;
	state[4] = 0x510E527F;
	state[5] = 0x9B05688C;
	state[6] = 0x1F83D9AB;
	state[7] = 0x5BE0CD19;
}

static const uint32_t passwdpad[12] = {0x00000080, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x80020000};
static const uint32_t outerpad[8] = {0x80000000, 0, 0, 0, 0, 0, 0, 0x00000300};

/**
 * PBKDF2_SHA256(passwd, passwdlen, salt, saltlen, c, buf, dkLen):
 * Compute PBKDF2(passwd, salt, c, dkLen) using HMAC-SHA256 as the PRF, and
 * write the output to buf.  The value dkLen must be at most 32 * (2^32 - 1).
 */
void PBKDF2_SHA256_80_128(const uint32_t * passwd, uint32_t * buf)
{
	SHA256_CTX PShictx, PShoctx;
	uint32_t tstate[8];
	uint32_t ihash[8];
	uint32_t i;
	uint32_t pad[16];
	
	static const uint32_t innerpad[11] = {0x00000080, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xa0040000};

	/* If Klen > 64, the key is really SHA256(K). */
	SHA256_InitState(tstate);
	SHA256_Transform(tstate, passwd, 1);
	memcpy(pad, passwd+16, 16);
	memcpy(pad+4, passwdpad, 48);
	SHA256_Transform(tstate, pad, 1);
	memcpy(ihash, tstate, 32);

	SHA256_InitState(PShictx.state);
	for (i = 0; i < 8; i++)
		pad[i] = ihash[i] ^ 0x36363636;
	for (; i < 16; i++)
		pad[i] = 0x36363636;
	SHA256_Transform(PShictx.state, pad, 0);
	SHA256_Transform(PShictx.state, passwd, 1);
	be32enc_vect(PShictx.buf, passwd+16, 4);
	be32enc_vect(PShictx.buf+5, innerpad, 11);

	SHA256_InitState(PShoctx.state);
	for (i = 0; i < 8; i++)
		pad[i] = ihash[i] ^ 0x5c5c5c5c;
	for (; i < 16; i++)
		pad[i] = 0x5c5c5c5c;
	SHA256_Transform(PShoctx.state, pad, 0);
	memcpy(PShoctx.buf+8, outerpad, 32);

	/* Iterate through the blocks. */
	swap32tole(PShictx.buf, PShictx.buf, 0x10);
	for (i = 0; i < 4; i++) {
		uint32_t istate[8];
		uint32_t ostate[8];
		
		memcpy(istate, PShictx.state, 32);
		PShictx.buf[4] = i + 1;
		SHA256_Transform(istate, PShictx.buf, 0);
		memcpy(PShoctx.buf, istate, 32);

		memcpy(ostate, PShoctx.state, 32);
		SHA256_Transform(ostate, PShoctx.buf, 0);
		swap32yes(buf+i*8, ostate, 8);
	}
}

void PBKDF2_SHA256_80_128_32(const uint32_t * passwd, const uint32_t * salt, uint32_t *ostate)
{
	uint32_t tstate[8];
	uint32_t ihash[8];
	uint32_t i;

	/* Compute HMAC state after processing P and S. */
	uint32_t pad[16];
	
	static const uint32_t ihash_finalblk[16] = {0x00000001,0x80000000,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0x00000620};

	/* If Klen > 64, the key is really SHA256(K). */
	SHA256_InitState(tstate);
	SHA256_Transform(tstate, passwd, 1);
	memcpy(pad, passwd+16, 16);
	memcpy(pad+4, passwdpad, 48);
	SHA256_Transform(tstate, pad, 1);
	memcpy(ihash, tstate, 32);

	SHA256_InitState(ostate);
	for (i = 0; i < 8; i++)
		pad[i] = ihash[i] ^ 0x5c5c5c5c;
	for (; i < 16; i++)
		pad[i] = 0x5c5c5c5c;
	SHA256_Transform(ostate, pad, 0);

	SHA256_InitState(tstate);
	for (i = 0; i < 8; i++)
		pad[i] = ihash[i] ^ 0x36363636;
	for (; i < 16; i++)
		pad[i] = 0x36363636;
	SHA256_Transform(tstate, pad, 0);
	SHA256_Transform(tstate, salt, 1);
	SHA256_Transform(tstate, salt+16, 1);
	SHA256_Transform(tstate, ihash_finalblk, 0);
	memcpy(pad, tstate, 32);
	memcpy(pad+8, outerpad, 32);

	/* Feed the inner hash to the outer SHA256 operation. */
	SHA256_Transform(ostate, pad, 0);
}

void salsa20_8(uint32_t B[16], const uint32_t Bx[16])
{
	uint32_t x00,x01,x02,x03,x04,x05,x06,x07,x08,x09,x10,x11,x12,x13,x14,x15;
	size_t i;

	x00 = (B[ 0] ^= Bx[ 0]);
	x01 = (B[ 1] ^= Bx[ 1]);
	x02 = (B[ 2] ^= Bx[ 2]);
	x03 = (B[ 3] ^= Bx[ 3]);
	x04 = (B[ 4] ^= Bx[ 4]);
	x05 = (B[ 5] ^= Bx[ 5]);
	x06 = (B[ 6] ^= Bx[ 6]);
	x07 = (B[ 7] ^= Bx[ 7]);
	x08 = (B[ 8] ^= Bx[ 8]);
	x09 = (B[ 9] ^= Bx[ 9]);
	x10 = (B[10] ^= Bx[10]);
	x11 = (B[11] ^= Bx[11]);
	x12 = (B[12] ^= Bx[12]);
	x13 = (B[13] ^= Bx[13]);
	x14 = (B[14] ^= Bx[14]);
	x15 = (B[15] ^= Bx[15]);
	for (i = 0; i < 8; i += 2) {
#define R(a,b) (((a) << (b)) | ((a) >> (32 - (b))))
		/* Operate on columns. */
		x04 ^= R(x00+x12, 7);	x09 ^= R(x05+x01, 7);	x14 ^= R(x10+x06, 7);	x03 ^= R(x15+x11, 7);
		x08 ^= R(x04+x00, 9);	x13 ^= R(x09+x05, 9);	x02 ^= R(x14+x10, 9);	x07 ^= R(x03+x15, 9);
		x12 ^= R(x08+x04,13);	x01 ^= R(x13+x09,13);	x06 ^= R(x02+x14,13);	x11 ^= R(x07+x03,13);
		x00 ^= R(x12+x08,18);	x05 ^= R(x01+x13,18);	x10 ^= R(x06+x02,18);	x15 ^= R(x11+x07,18);

		/* Operate on rows. */
		x01 ^= R(x00+x03, 7);	x06 ^= R(x05+x04, 7);	x11 ^= R(x10+x09, 7);	x12 ^= R(x15+x14, 7);
		x02 ^= R(x01+x00, 9);	x07 ^= R(x06+x05, 9);	x08 ^= R(x11+x10, 9);	x13 ^= R(x12+x15, 9);
		x03 ^= R(x02+x01,13);	x04 ^= R(x07+x06,13);	x09 ^= R(x08+x11,13);	x14 ^= R(x13+x12,13);
		x00 ^= R(x03+x02,18);	x05 ^= R(x04+x07,18);	x10 ^= R(x09+x08,18);	x15 ^= R(x14+x13,18);
#undef R
	}
	B[ 0] += x00;
	B[ 1] += x01;
	B[ 2] += x02;
	B[ 3] += x03;
	B[ 4] += x04;
	B[ 5] += x05;
	B[ 6] += x06;
	B[ 7] += x07;
	B[ 8] += x08;
	B[ 9] += x09;
	B[10] += x10;
	B[11] += x11;
	B[12] += x12;
	B[13] += x13;
	B[14] += x14;
	B[15] += x15;
}

void scrypt_1024_1_1_256_sp(const uint32_t* input, char* scratchpad, uint32_t *ostate, uint8_t varity)
{
	uint32_t * V;
	uint32_t X[32];
	uint32_t i;
	uint32_t j;
	uint32_t k;
	uint64_t *p1, *p2;

	p1 = (uint64_t *)X;
	V = (uint32_t *)(((uintptr_t)(scratchpad) + 63) & ~ (uintptr_t)(63));

	PBKDF2_SHA256_80_128(input, X);

	for (i = 0; i < 1024; i += 2) {
		memcpy(&V[i * 32], X, 128);

		salsa20_8(&X[0], &X[16]);
		salsa20_8(&X[16], &X[0]);

		memcpy(&V[(i + 1) * 32], X, 128);

		salsa20_8(&X[0], &X[16]);
		salsa20_8(&X[16], &X[0]);
	}
	for (i = 0; i < 1024; i += 2) {
		j = X[16] & 1023;
		p2 = (uint64_t *)(&V[j * 32]);
		for(k = 0; k < 16; k++)
			p1[k] ^= p2[k];

		salsa20_8(&X[0], &X[16]);
		salsa20_8(&X[16], &X[0]);

		j = X[16] & 1023;
		p2 = (uint64_t *)(&V[j * 32]);
		for(k = 0; k < 16; k++)
			p1[k] ^= p2[k];

		salsa20_8(&X[0], &X[16]);
		salsa20_8(&X[16], &X[0]);
	}

    X[0] += (varity << 24);

	PBKDF2_SHA256_80_128_32(input, X, ostate);
}

#define SCRATCHBUF_SIZE	(131584)

void scrypt_hash_data(void *out_hash, const void * const pdata, uint8_t varity)
{
	uint32_t data[20], ohash[8];
	void *scratchbuf;

  //be32enc_vect(data, (uint32_t *)pdata, 20);
	memcpy(data, pdata, 80);
	//printf("Data Before 32DB:\n");
	//for(int i = 0; i< 80; i++)
	//printf("%02x", *((uint8_t *)data + i));
	//printf("\n");
	scratchbuf = malloc(SCRATCHBUF_SIZE);
	scrypt_1024_1_1_256_sp((uint32_t *)data, (char *)scratchbuf, ohash, varity);
  swap32tobe(out_hash, ohash, 32/4);
	free(scratchbuf);
}

NAN_METHOD(genHash) {
    char * pdata = (char *)node::Buffer::Data(info[0]->ToObject());
    unsigned int size = info[1]->Uint32Value();
    unsigned int mode = info[2]->Uint32Value();
		v8::Local<v8::Object> buf = Nan::NewBuffer(32).ToLocalChecked();
		char * outhash =  (char *)node::Buffer::Data(buf);
    //printf("scrypt Genhash\n");
    // char *outhash = new char[32];

    scrypt_hash_data(outhash, pdata, mode);
    info.GetReturnValue().Set(buf);
}

NAN_MODULE_INIT(Init) {  
   Nan::Set(target, New<String>("genHash").ToLocalChecked(),
        GetFunction(New<FunctionTemplate>(genHash)).ToLocalChecked());
}

NODE_MODULE(scrypt, Init)