// KuwoDES加密，从隔壁Python版移植
// 由 BingChat/GPT-4 提供代码翻译
// (因为位运算优先级的问题搞了半天)
// 另一个Go版本(未测试)：https://github.com/cnsilvan/UnblockNeteaseMusic/tree/master/provider/kuwo

package kw

import (
	"encoding/base64"

	"github.com/ZxwyWebSite/ztool/x/bytesconv"
	"github.com/ZxwyWebSite/ztool/zcypt"
)

// 常量和数组
const (
	DES_MODE_DECRYPT = 1
)

var (
	arrayE = []int64{
		31, 0, DES_MODE_DECRYPT, 2, 3, 4, -1, -1, 3, 4, 5, 6, 7, 8, -1, -1, 7, 8, 9, 10, 11, 12, -1, -1, 11, 12, 13, 14, 15, 16, -1, -1,
		15, 16, 17, 18, 19, 20, -1, -1, 19, 20, 21, 22, 23, 24, -1, -1,
		23, 24, 25, 26, 27, 28, -1, -1, 27, 28, 29, 30, 31, 30, -1, -1,
	}
	arrayIP = []int64{
		57, 49, 41, 33, 25, 17, 9, DES_MODE_DECRYPT, 59, 51, 43, 35, 27, 19, 11, 3, 61, 53, 45, 37, 29, 21, 13, 5, 63, 55, 47, 39, 31, 23, 15, 7, 56, 48, 40, 32, 24, 16, 8, 0, 58, 50, 42, 34, 26, 18, 10, 2, 60, 52, 44, 36, 28, 20, 12, 4, 62, 54, 46, 38, 30, 22, 14, 6,
	}
	arrayIP_1 = []int64{
		39, 7, 47, 15, 55, 23, 63, 31, 38, 6, 46, 14, 54, 22, 62, 30, 37, 5, 45, 13, 53, 21, 61, 29, 36, 4, 44, 12, 52, 20, 60, 28, 35, 3, 43, 11, 51, 19, 59, 27, 34, 2, 42, 10, 50, 18, 58, 26, 33, DES_MODE_DECRYPT, 41, 9, 49, 17, 57, 25, 32, 0, 40, 8, 48, 16, 56, 24,
	}
	arrayLs     = []int64{1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1}
	arrayLsMask = []int64{0, 0x100001, 0x300003}
	arrayMask   = make([]int64, 64)
	arrayP      = []int64{
		15, 6, 19, 20, 28, 11, 27, 16,
		0, 14, 22, 25, 4, 17, 30, 9,
		1, 7, 23, 13, 31, 26, 2, 8,
		18, 12, 29, 5, 21, 10, 3, 24,
	}
	arrayPC_1 = []int64{
		56, 48, 40, 32, 24, 16, 8, 0,
		57, 49, 41, 33, 25, 17, 9, 1,
		58, 50, 42, 34, 26, 18, 10, 2,
		59, 51, 43, 35, 62, 54, 46, 38,
		30, 22, 14, 6, 61, 53, 45, 37,
		29, 21, 13, 5, 60, 52, 44, 36,
		28, 20, 12, 4, 27, 19, 11, 3,
	}
	arrayPC_2 = []int64{
		13, 16, 10, 23, 0, 4, -1, -1,
		2, 27, 14, 5, 20, 9, -1, -1,
		22, 18, 11, 3, 25, 7, -1, -1,
		15, 6, 26, 19, 12, 1, -1, -1,
		40, 51, 30, 36, 46, 54, -1, -1,
		29, 39, 50, 44, 32, 47, -1, -1,
		43, 48, 38, 55, 33, 52, -1, -1,
		45, 41, 49, 35, 28, 31, -1, -1,
	}
	matrixNSBox = [...][]int64{{
		14, 4, 3, 15, 2, 13, 5, 3,
		13, 14, 6, 9, 11, 2, 0, 5,
		4, 1, 10, 12, 15, 6, 9, 10,
		1, 8, 12, 7, 8, 11, 7, 0,
		0, 15, 10, 5, 14, 4, 9, 10,
		7, 8, 12, 3, 13, 1, 3, 6,
		15, 12, 6, 11, 2, 9, 5, 0,
		4, 2, 11, 14, 1, 7, 8, 13}, {
		15, 0, 9, 5, 6, 10, 12, 9,
		8, 7, 2, 12, 3, 13, 5, 2,
		1, 14, 7, 8, 11, 4, 0, 3,
		14, 11, 13, 6, 4, 1, 10, 15,
		3, 13, 12, 11, 15, 3, 6, 0,
		4, 10, 1, 7, 8, 4, 11, 14,
		13, 8, 0, 6, 2, 15, 9, 5,
		7, 1, 10, 12, 14, 2, 5, 9}, {
		10, 13, 1, 11, 6, 8, 11, 5,
		9, 4, 12, 2, 15, 3, 2, 14,
		0, 6, 13, 1, 3, 15, 4, 10,
		14, 9, 7, 12, 5, 0, 8, 7,
		13, 1, 2, 4, 3, 6, 12, 11,
		0, 13, 5, 14, 6, 8, 15, 2,
		7, 10, 8, 15, 4, 9, 11, 5,
		9, 0, 14, 3, 10, 7, 1, 12}, {
		7, 10, 1, 15, 0, 12, 11, 5,
		14, 9, 8, 3, 9, 7, 4, 8,
		13, 6, 2, 1, 6, 11, 12, 2,
		3, 0, 5, 14, 10, 13, 15, 4,
		13, 3, 4, 9, 6, 10, 1, 12,
		11, 0, 2, 5, 0, 13, 14, 2,
		8, 15, 7, 4, 15, 1, 10, 7,
		5, 6, 12, 11, 3, 8, 9, 14}, {
		2, 4, 8, 15, 7, 10, 13, 6,
		4, 1, 3, 12, 11, 7, 14, 0,
		12, 2, 5, 9, 10, 13, 0, 3,
		1, 11, 15, 5, 6, 8, 9, 14,
		14, 11, 5, 6, 4, 1, 3, 10,
		2, 12, 15, 0, 13, 2, 8, 5,
		11, 8, 0, 15, 7, 14, 9, 4,
		12, 7, 10, 9, 1, 13, 6, 3}, {
		12, 9, 0, 7, 9, 2, 14, 1,
		10, 15, 3, 4, 6, 12, 5, 11,
		1, 14, 13, 0, 2, 8, 7, 13,
		15, 5, 4, 10, 8, 3, 11, 6,
		10, 4, 6, 11, 7, 9, 0, 6,
		4, 2, 13, 1, 9, 15, 3, 8,
		15, 3, 1, 14, 12, 5, 11, 0,
		2, 12, 14, 7, 5, 10, 8, 13}, {
		4, 1, 3, 10, 15, 12, 5, 0,
		2, 11, 9, 6, 8, 7, 6, 9,
		11, 4, 12, 15, 0, 3, 10, 5,
		14, 13, 7, 8, 13, 14, 1, 2,
		13, 6, 14, 9, 4, 1, 2, 14,
		11, 13, 5, 0, 1, 10, 8, 3,
		0, 11, 3, 5, 9, 4, 15, 2,
		7, 8, 12, 15, 10, 7, 6, 12}, {
		13, 7, 10, 0, 6, 9, 5, 15,
		8, 4, 3, 10, 11, 14, 12, 5,
		2, 11, 9, 6, 15, 12, 0, 3,
		4, 1, 14, 13, 1, 2, 7, 8,
		1, 2, 12, 15, 10, 4, 0, 3,
		13, 14, 6, 9, 7, 8, 9, 6,
		15, 1, 5, 12, 3, 10, 14, 5,
		8, 7, 11, 0, 4, 13, 2, 11},
	}
	SECRET_KEY = []byte{0x79, 0x6c, 0x7a, 0x73, 0x78, 0x6b, 0x77, 0x6d} //bytesconv.StringToBytes(`ylzsxkwm`)
)

// 初始化arrayMask
func init() {
	for i := range arrayMask {
		arrayMask[i] = 1 << i
	}
	arrayMask[63] *= -1
}

// 位变换函数
func bit_transform(arr_int []int64, n int, l int64) (l2 int64) {
	// l2 := 0
	for i := 0; i < n; i++ {
		if arr_int[i] < 0 || (l&arrayMask[arr_int[i]]) == 0 {
			continue
		}
		l2 |= arrayMask[i]
	}
	return //l2
}

// DES加密函数
func _DES64(longs []int64, l int64) (out int64) {
	// out := 0
	// SOut := 0
	pR := make([]int64, 8)
	pSource := make([]int64, 2) //[]int64{0, 0}
	// sbi := 0
	// t := 0
	// L := 0
	// R := 0
	out = bit_transform(arrayIP, 64, l)
	pSource[0] = 0xFFFFFFFF & out
	pSource[1] = (-4294967296 & out) >> 32
	for i := 0; i < 16; i++ {
		R := pSource[1]
		R = bit_transform(arrayE, 64, R)
		R ^= longs[i]
		for j := 0; j < 8; j++ {
			pR[j] = 255 & (R >> (j * 8))
		}
		var SOut int64
		for sbi := 7; sbi >= 0; sbi-- {
			SOut <<= 4
			SOut |= matrixNSBox[sbi][pR[sbi]]
		}

		R = bit_transform(arrayP, 32, SOut)
		L := pSource[0]
		pSource[0] = pSource[1]
		pSource[1] = L ^ R
	}
	pSource = []int64{pSource[1], pSource[0]}
	out = (-4294967296 & (pSource[1] << 32)) | (0xFFFFFFFF & pSource[0])
	out = bit_transform(arrayIP_1, 64, out)
	return //out
}

// 生成子密钥函数
func sub_keys(l int64, longs []int64, n int) {
	l2 := bit_transform(arrayPC_1, 56, l)
	for i := 0; i < 16; i++ {
		l2 = ((l2 & arrayLsMask[arrayLs[i]]) << (28 - arrayLs[i])) | ((l2 & ^arrayLsMask[arrayLs[i]]) >> arrayLs[i])
		longs[i] = bit_transform(arrayPC_2, 64, l2)
	}
	j := 0
	for n == 1 && j < 8 {
		// l3 := longs[j]
		longs[j], longs[15-j] = longs[15-j], longs[j]
		j++
	}
}

// 加密函数
func encrypt(msg []byte, key []byte) []byte {
	// if len(key) != 8 {
	// 	panic("key length must be 8 bytes")
	// }

	// 处理密钥块
	var l int64
	for i := 0; i < 8; i++ {
		l = l | int64(key[i])<<(i*8)
	}

	j := len(msg) / 8
	// arrLong1 存放的是转换后的密钥块, 在解密时只需要把这个密钥块反转就行了
	arrLong1 := make([]int64, 16)
	sub_keys(l, arrLong1, 0)
	// arrLong2 存放的是前部分的明文
	arrLong2 := make([]int64, j)
	for m := 0; m < j; m++ {
		for n := 0; n < 8; n++ {
			arrLong2[m] |= int64(msg[n+m*8]) << (n * 8)
		}
	}

	// 用于存放密文
	arrLong3 := make([]int64, (1+8*(j+1))/8)
	// 计算前部的数据块(除了最后一部分)
	for i1 := 0; i1 < j; i1++ {
		arrLong3[i1] = _DES64(arrLong1, arrLong2[i1])
	}

	// 保存多出来的字节
	arrByte1 := msg[j*8:]
	var l2 int64
	for i1 := 0; i1 < len(msg)%8; i1++ {
		l2 |= int64(arrByte1[i1]) << (i1 * 8)
	}
	// 计算多出的那一位(最后一位)
	arrLong3[j] = _DES64(arrLong1, l2)

	// 将密文转为字节型
	arrByte2 := make([]byte, 8*len(arrLong3))
	i4 := 0
	for _, l3 := range arrLong3 {
		for i6 := 0; i6 < 8; i6++ {
			arrByte2[i4] = byte(255 & (l3 >> (i6 * 8)))
			i4++
		}
	}
	return arrByte2
}

// base64编码函数
func base64_encrypt(msg string) string {
	b1 := encrypt(bytesconv.StringToBytes(msg), SECRET_KEY)
	return zcypt.Base64ToString(base64.StdEncoding, b1)
	// s := base64.StdEncoding.EncodeToString(b1)
	// return s //strings.ReplaceAll(s, "\n", ``)
}