package sm1

import (
	"encoding/binary"
)

// type roundKey = [4 * (numOfRound + 1)]uint32
type roundKey []uint32

// //	func newRoundKey() AC_SM1_KEY {
// //		return make([]uint32, 4*(numOfRound+1))
// //	}
// func (k AC_SM1_KEY) clear() {
// 	for i := range k {
// 		k[i] = 0
// 	}
// }

func sbox2(sbox1, sbox2 []byte, x byte) byte {
	return ((sbox1[(x>>4)&0x0f] << 4) | sbox2[x&0x0f])
}

func g(out, inX, inY []uint32) {
	var sbox = [][]byte{
		{0x5, 0xd, 0x9, 0x1, 0x0, 0x2, 0xa, 0xf, 0x6, 0x7, 0xc, 0x8, 0xe, 0x3, 0xb, 0x4},
		{0x2, 0x4, 0xf, 0x6, 0x8, 0xb, 0xe, 0x5, 0xa, 0xd, 0x3, 0xc, 0x9, 0x7, 0x1, 0x0},
		{0x4, 0x3, 0x5, 0xd, 0xf, 0x0, 0x8, 0x9, 0xb, 0x2, 0x6, 0xe, 0xa, 0x1, 0xc, 0x7},
		{0xf, 0xe, 0x0, 0xa, 0x1, 0x7, 0x3, 0xd, 0x4, 0xc, 0x8, 0x5, 0xb, 0x9, 0x6, 0x2},
		{0x4, 0xc, 0x8, 0x0, 0x1, 0x3, 0xb, 0xe, 0x7, 0x6, 0xd, 0x9, 0xf, 0x2, 0xa, 0x5},
		{0x1, 0x7, 0xc, 0x5, 0xb, 0x8, 0xd, 0x6, 0x9, 0xe, 0x0, 0xf, 0xa, 0x4, 0x2, 0x3},
		{0xd, 0xa, 0xc, 0x4, 0x6, 0x9, 0x1, 0x0, 0x2, 0xb, 0xf, 0x7, 0x3, 0x8, 0x5, 0xe},
		{0x9, 0x8, 0x6, 0xc, 0x7, 0x1, 0x5, 0xb, 0x2, 0xa, 0xe, 0x3, 0xd, 0xf, 0x0, 0x4}}
	xx := make([]uint32, 4)
	xxx := make([]uint32, 4)
	xx[0] = inX[0] ^ inX[2] ^ inX[3]
	xx[1] = inX[0] ^ inX[1] ^ inX[3]
	xx[2] = inX[0] ^ inX[2] ^ inX[1]
	xx[3] = inX[0] ^ inX[1] ^ inX[2] ^ inX[3]

	xxx[0] = xx[0] ^ inY[0]
	xxx[1] = xx[1] ^ inY[1]
	xxx[2] = xx[2] ^ inY[2]
	s := make([]byte, 4)
	// int2bytes(s, xx[3])
	binary.BigEndian.PutUint32(s, xx[3])
	// printf("s[0-3]=%02x%02x%02x%02x\n", s[0], s[1], s[2], s[3]);
	s[0] = sbox2(sbox[0], sbox[1], s[0])
	s[1] = sbox2(sbox[2], sbox[3], s[1])
	// printf("s[0-3]=%02x%02x%02x%02x\n", s[0], s[1], s[2], s[3]);
	s[2] = sbox2(sbox[4], sbox[5], s[2])
	// printf("s[0-3]=%02x%02x%02x%02x\n", s[0], s[1], s[2], s[3]);
	s[3] = sbox2(sbox[6], sbox[7], s[3])
	// printf("s[0-3]=%02x%02x%02x%02x\n", s[0], s[1], s[2], s[3]);
	xxx[3] = binary.BigEndian.Uint32(s) // bytes2int(s);

	out[0] = rol(xxx[3], 1) ^ inY[3]
	out[1] = rol(xxx[0], 8) ^ rol(xxx[3], 17)
	out[2] = rol(xxx[1], 7) ^ rol(xxx[3], 25)
	out[3] = rol(xxx[2], 1) ^ rol(xxx[3], 9)
}

func gg(out, inX, inY []uint32) {
	var sbox = [][]byte{
		{0x4, 0x3, 0x5, 0xd, 0xf, 0x0, 0x8, 0x9, 0xb, 0x2, 0x6, 0xe, 0xa, 0x1, 0xc, 0x7},
		{0xf, 0xe, 0x0, 0xa, 0x1, 0x7, 0x3, 0xd, 0x4, 0xc, 0x8, 0x5, 0xb, 0x9, 0x6, 0x2},
		{0x5, 0xd, 0x9, 0x1, 0x0, 0x2, 0xa, 0xf, 0x6, 0x7, 0xc, 0x8, 0xe, 0x3, 0xb, 0x4},
		{0x2, 0x4, 0xf, 0x6, 0x8, 0xb, 0xe, 0x5, 0xa, 0xd, 0x3, 0xc, 0x9, 0x7, 0x1, 0x0},
		{0x3, 0x4, 0xd, 0x5, 0x0, 0xf, 0x9, 0x8, 0x2, 0xb, 0xe, 0x6, 0x1, 0xa, 0x7, 0xc},
		{0xa, 0x0, 0xe, 0xf, 0xd, 0x3, 0x7, 0x1, 0x5, 0x8, 0xc, 0x4, 0x2, 0x6, 0x9, 0xb},
		{0x7, 0x6, 0x8, 0xc, 0x3, 0xe, 0x4, 0xb, 0xd, 0x5, 0x1, 0x9, 0x2, 0x0, 0xf, 0xa},
		{0xe, 0x5, 0x8, 0xb, 0xf, 0x6, 0x2, 0x4, 0x1, 0x0, 0x9, 0x7, 0x3, 0xc, 0xa, 0xd},
	}
	xx := make([]uint32, 4)
	xxx := make([]uint32, 4)
	xx[3] = ror(inX[0]^inY[3], 1)
	xx[2] = ror(rol(xx[3], 9)^inX[3], 1)
	xx[1] = ror(rol(xx[3], 25)^inX[2], 7)
	xx[0] = ror(rol(xx[3], 17)^inX[1], 8)

	xxx[0] = xx[0] ^ inY[0]
	xxx[1] = xx[1] ^ inY[1]
	xxx[2] = xx[2] ^ inY[2]
	s := make([]byte, 4)
	binary.BigEndian.PutUint32(s, xx[3])
	s[0] = sbox2(sbox[0], sbox[1], s[0])
	s[1] = sbox2(sbox[2], sbox[3], s[1])
	s[2] = sbox2(sbox[4], sbox[5], s[2])
	s[3] = sbox2(sbox[6], sbox[7], s[3])
	xxx[3] = binary.BigEndian.Uint32(s)

	out[0] = xxx[0] ^ xxx[1] ^ xxx[2]
	out[1] = xxx[0] ^ xxx[3]
	out[2] = xxx[3] ^ xxx[1]
	out[3] = xxx[2] ^ xxx[3]
}

func xor(c, a, b []uint32) {
	for i := range a {
		c[i] = a[i] ^ b[i]
	}
}

func keyexpand(A, B [][]uint32, ek []byte) {
	// static const unsigned char sk[AC_SM1_KEY_LENGTH_IN_BYTE] = {0x19, 0x1a, 0x4e, 0xf3, 0x67, 0xec, 0xe2, 0x81, 0xc9, 0x03, 0xc4, 0x6c, 0x23, 0x33, 0x3c, 0x2a};
	// static const unsigned char ak[AC_SM1_KEY_LENGTH_IN_BYTE] = {0};
	EK := make([]uint32, 4)

	// 辅助密钥AK为全0
	// uint32_t AK[4] = {0};

	// 系统密钥
	SK := []uint32{0x191a4ef3, 0x67ece281, 0xc903c46c, 0x23333c2a}

	bytes2ints(EK, ek)
	a := make([]uint32, 4)
	b := make([]uint32, 4)
	xor(SK, EK, SK)
	a[0] = SK[1] ^ SK[2] ^ SK[3]
	a[1] = SK[1] ^ SK[2] ^ SK[0]
	a[2] = SK[1] ^ SK[0] ^ SK[3]
	a[3] = SK[0] ^ SK[2] ^ SK[3]
	// a[0] = a[0];
	a[1] = rol(a[1], 8)
	a[2] = rol(a[2], 16)
	a[3] = rol(a[3], 23)

	// xor(i, EK, AK, 4);
	b[0] = EK[1] ^ EK[2] ^ EK[3]
	b[1] = EK[1] ^ EK[2] ^ EK[0]
	b[2] = EK[1] ^ EK[0] ^ EK[3]
	b[3] = EK[0] ^ EK[2] ^ EK[3]
	b[0] = rol(b[0], 8)
	b[1] = rol(b[1], 16)
	b[2] = rol(b[2], 24)
	// b[3] = b[3];

	g(A[0], a, b)
	gg(B[0], b, a)
	for i := 1; i < numOfRound/2+1; i++ {
		g(A[i], A[i-1], b)
		gg(B[i], B[i-1], a)
	}
	for i := numOfRound/2 + 1; i < numOfRound+1; i++ {
		gg(A[i], A[i-1], b)
		g(B[i], B[i-1], a)
	}

}

func keyexpand_enc(rkey []uint32, ek []byte) {
	A := make([][]uint32, numOfRound+1)
	for i := range A {
		A[i] = make([]uint32, 4)
	}
	B := make([][]uint32, numOfRound+1)
	for i := range B {
		B[i] = make([]uint32, 4)
	}

	keyexpand(A, B, ek)
	j := 0
	for ; j < numOfRound/2+1; j++ {
		rkey[4*j+0] = A[j][0]
		rkey[4*j+1] = A[j][1]
		rkey[4*j+2] = A[j][2]
		rkey[4*j+3] = A[j][3]
	}
	for ; j < numOfRound+1; j++ {
		rkey[4*j+0] = B[j][0]
		rkey[4*j+1] = B[j][1]
		rkey[4*j+2] = B[j][2]
		rkey[4*j+3] = B[j][3]
	}
}
func keyexpand_dec(rkey []uint32, ek []byte) {
	A := make([][]uint32, numOfRound+1)
	for i := range A {
		A[i] = make([]uint32, 4)
	}
	B := make([][]uint32, numOfRound+1)
	for i := range B {
		B[i] = make([]uint32, 4)
	}

	keyexpand(A, B, ek)
	j := 0
	for ; j < numOfRound/2; j++ {
		rkey[4*j+0] = B[j][0]
		rkey[4*j+1] = B[j][1]
		rkey[4*j+2] = B[j][2]
		rkey[4*j+3] = B[j][3]
	}
	for ; j < numOfRound+1; j++ {
		rkey[4*j+0] = A[j][0]
		rkey[4*j+1] = A[j][1]
		rkey[4*j+2] = A[j][2]
		rkey[4*j+3] = A[j][3]
	}
	for j = 0; j < numOfRound+1; j++ {
		rr(rkey[4*j:], rkey[4*j:])
	}
}