/* eslint-disable */

import Crypt from './crypt';

const UINT8_BLOCK = 16;

const Sbox = Uint8Array.from([
  0xd6, 0x90, 0xe9, 0xfe, 0xcc, 0xe1, 0x3d, 0xb7, 0x16, 0xb6, 0x14, 0xc2, 0x28, 0xfb, 0x2c, 0x05, 0x2b, 0x67, 0x9a,
  0x76, 0x2a, 0xbe, 0x04, 0xc3, 0xaa, 0x44, 0x13, 0x26, 0x49, 0x86, 0x06, 0x99, 0x9c, 0x42, 0x50, 0xf4, 0x91, 0xef,
  0x98, 0x7a, 0x33, 0x54, 0x0b, 0x43, 0xed, 0xcf, 0xac, 0x62, 0xe4, 0xb3, 0x1c, 0xa9, 0xc9, 0x08, 0xe8, 0x95, 0x80,
  0xdf, 0x94, 0xfa, 0x75, 0x8f, 0x3f, 0xa6, 0x47, 0x07, 0xa7, 0xfc, 0xf3, 0x73, 0x17, 0xba, 0x83, 0x59, 0x3c, 0x19,
  0xe6, 0x85, 0x4f, 0xa8, 0x68, 0x6b, 0x81, 0xb2, 0x71, 0x64, 0xda, 0x8b, 0xf8, 0xeb, 0x0f, 0x4b, 0x70, 0x56, 0x9d,
  0x35, 0x1e, 0x24, 0x0e, 0x5e, 0x63, 0x58, 0xd1, 0xa2, 0x25, 0x22, 0x7c, 0x3b, 0x01, 0x21, 0x78, 0x87, 0xd4, 0x00,
  0x46, 0x57, 0x9f, 0xd3, 0x27, 0x52, 0x4c, 0x36, 0x02, 0xe7, 0xa0, 0xc4, 0xc8, 0x9e, 0xea, 0xbf, 0x8a, 0xd2, 0x40,
  0xc7, 0x38, 0xb5, 0xa3, 0xf7, 0xf2, 0xce, 0xf9, 0x61, 0x15, 0xa1, 0xe0, 0xae, 0x5d, 0xa4, 0x9b, 0x34, 0x1a, 0x55,
  0xad, 0x93, 0x32, 0x30, 0xf5, 0x8c, 0xb1, 0xe3, 0x1d, 0xf6, 0xe2, 0x2e, 0x82, 0x66, 0xca, 0x60, 0xc0, 0x29, 0x23,
  0xab, 0x0d, 0x53, 0x4e, 0x6f, 0xd5, 0xdb, 0x37, 0x45, 0xde, 0xfd, 0x8e, 0x2f, 0x03, 0xff, 0x6a, 0x72, 0x6d, 0x6c,
  0x5b, 0x51, 0x8d, 0x1b, 0xaf, 0x92, 0xbb, 0xdd, 0xbc, 0x7f, 0x11, 0xd9, 0x5c, 0x41, 0x1f, 0x10, 0x5a, 0xd8, 0x0a,
  0xc1, 0x31, 0x88, 0xa5, 0xcd, 0x7b, 0xbd, 0x2d, 0x74, 0xd0, 0x12, 0xb8, 0xe5, 0xb4, 0xb0, 0x89, 0x69, 0x97, 0x4a,
  0x0c, 0x96, 0x77, 0x7e, 0x65, 0xb9, 0xf1, 0x09, 0xc5, 0x6e, 0xc6, 0x84, 0x18, 0xf0, 0x7d, 0xec, 0x3a, 0xdc, 0x4d,
  0x20, 0x79, 0xee, 0x5f, 0x3e, 0xd7, 0xcb, 0x39, 0x48,
]);

const CK = Uint32Array.from([
  0x00070e15, 0x1c232a31, 0x383f464d, 0x545b6269, 0x70777e85, 0x8c939aa1, 0xa8afb6bd, 0xc4cbd2d9, 0xe0e7eef5,
  0xfc030a11, 0x181f262d, 0x343b4249, 0x50575e65, 0x6c737a81, 0x888f969d, 0xa4abb2b9, 0xc0c7ced5, 0xdce3eaf1,
  0xf8ff060d, 0x141b2229, 0x30373e45, 0x4c535a61, 0x686f767d, 0x848b9299, 0xa0a7aeb5, 0xbcc3cad1, 0xd8dfe6ed,
  0xf4fb0209, 0x10171e25, 0x2c333a41, 0x484f565d, 0x646b7279,
]);

const FK = Uint32Array.from([0xa3b1bac6, 0x56aa3350, 0x677d9197, 0xb27022dc]);

class SM4 {
  /**
   * Creates an instance of SM4.
   * @param {Object} config
   * @memberof SM4
   */
  constructor(config) {
    const keyBuffer = Crypt.stringToArrayBufferInUtf8(config.key);
    if (keyBuffer.length !== 16) {
      throw new Error('key should be a 16 bytes string');
    }

    /**
     * key should be 16 bytes string
     * @member {Uint8Array} key
     */
    this.key = keyBuffer;

    /**
     * iv also should be 16 bytes string
     * @member {Uint8Array} iv
     */
    let ivBuffer = new Uint8Array(0);
    if (config.iv !== undefined && config.iv !== null) {
      // need iv
      ivBuffer = Crypt.stringToArrayBufferInUtf8(config.iv);
      if (ivBuffer.length !== 16) {
        throw new Error('iv should be a 16 bytes string');
      }
    }
    this.iv = ivBuffer;

    /**
     * sm4's encrypt mode
     * @member {Enum} mode
     */
    this.mode = 'cbc';
    if (['cbc', 'ecb'].indexOf(config.mode) >= 0) {
      // set encrypt mode. default is cbc
      this.mode = config.mode;
    }

    /**
     * sm4's cipher data type
     * @member {Enum} outType
     */
    this.cipherType = 'base64';
    if (['base64', 'text'].indexOf(config.outType) >= 0) {
      // set encrypt mode. default is cbc
      this.cipherType = config.outType;
    }

    /**
     * sm4's encrypt round key array
     * @member {Uint32Array} encryptRoundKeys
     */
    this.encryptRoundKeys = new Uint32Array(32);
    // spawn 32 round keys
    this.spawnEncryptRoundKeys();

    /**
     * sm4's decrypt round key array
     * @member {Uint32Array} encryptRoundKeys
     */
    this.decryptRoundKeys = Uint32Array.from(this.encryptRoundKeys);
    this.decryptRoundKeys.reverse();
  }

  /**
   * general sm4 encrypt/decrypt algorithm for a 16 bytes block using roundKey
   *
   * @param {Uint32Array} blockData
   * @param {Uint32Array} roundKeys
   * @return {Uint32Array} return a 16 bytes cipher block
   * @memberof SM4
   */
  doBlockCrypt(blockData, roundKeys) {
    const xBlock = new Uint32Array(36);
    xBlock.set(blockData, 0);
    // loop to process 32 rounds crypt
    for (let i = 0; i < 32; i++) {
      xBlock[i + 4] = xBlock[i] ^ this.tTransform1(xBlock[i + 1] ^ xBlock[i + 2] ^ xBlock[i + 3] ^ roundKeys[i]);
    }
    const yBlock = new Uint32Array(4);
    // reverse last 4 xBlock member
    yBlock[0] = xBlock[35];
    yBlock[1] = xBlock[34];
    yBlock[2] = xBlock[33];
    yBlock[3] = xBlock[32];
    return yBlock;
  }

  /**
   * spawn round key array for encrypt. reverse this key array when decrypt.
   * every round key's length is 32 bytes.
   * there are 32 round keys.
   * @return {Uint32Array}
   * @memberof SM4
   */
  spawnEncryptRoundKeys() {
    // extract mk in key
    const mk = new Uint32Array(4);
    mk[0] = (this.key[0] << 24) | (this.key[1] << 16) | (this.key[2] << 8) | this.key[3];
    mk[1] = (this.key[4] << 24) | (this.key[5] << 16) | (this.key[6] << 8) | this.key[7];
    mk[2] = (this.key[8] << 24) | (this.key[9] << 16) | (this.key[10] << 8) | this.key[11];
    mk[3] = (this.key[12] << 24) | (this.key[13] << 16) | (this.key[14] << 8) | this.key[15];
    // calculate the K array
    const k = new Uint32Array(36);
    k[0] = mk[0] ^ FK[0];
    k[1] = mk[1] ^ FK[1];
    k[2] = mk[2] ^ FK[2];
    k[3] = mk[3] ^ FK[3];
    // loop to spawn 32 round keys
    for (let i = 0; i < 32; i++) {
      k[i + 4] = k[i] ^ this.tTransform2(k[i + 1] ^ k[i + 2] ^ k[i + 3] ^ CK[i]);
      this.encryptRoundKeys[i] = k[i + 4];
    }
  }

  /**
   * left rotate x by y bits
   *
   * @param {*} x
   * @param {Number} y
   * @returns
   * @memberof SM4
   */
  rotateLeft(x, y) {
    return (x << y) | (x >>> (32 - y));
  }

  /**
   * L transform function for encrypt
   *
   * @param {Uint32Number} b
   * @returns {Uint32Number}
   * @memberof SM4
   */
  linearTransform1(b) {
    return b ^ this.rotateLeft(b, 2) ^ this.rotateLeft(b, 10) ^ this.rotateLeft(b, 18) ^ this.rotateLeft(b, 24);
  }

  /**
   * L' transform function for key expand
   *
   * @param {Uint32Number} b
   * @returns {Uint32Number}
   * @memberof SM4
   */
  linearTransform2(b) {
    return b ^ this.rotateLeft(b, 13) ^ this.rotateLeft(b, 23);
  }

  /**
   * τ transform function
   *
   * @param {Uint32Number} a
   * @returns {Uint32Number}
   * @memberof SM4
   */
  tauTransform(a) {
    return (
      (Sbox[(a >>> 24) & 0xff] << 24) | (Sbox[(a >>> 16) & 0xff] << 16) | (Sbox[(a >>> 8) & 0xff] << 8) | Sbox[a & 0xff]
    );
  }

  /**
   * mix replacement T transform for encrypt
   *
   * @param {Uint32Number} z
   * @returns {Uint32Number}
   * @memberof SM4
   */
  tTransform1(z) {
    const b = this.tauTransform(z);
    const c = this.linearTransform1(b);
    return c;
  }

  /**
   * mix replacement T transform for key expand
   *
   * @param {Uint32Number} z
   * @returns {Uint32Number}
   * @memberof SM4
   */
  tTransform2(z) {
    const b = this.tauTransform(z);
    const c = this.linearTransform2(b);
    return c;
  }

  /**
   * padding the array length to multiple of BLOCK
   *
   * @param {ByteArray} originalBuffer
   * @returns {ByteArray}
   * @memberof SM4
   */
  padding(originalBuffer) {
    if (originalBuffer === null) {
      return null;
    }
    const paddingLength = UINT8_BLOCK - (originalBuffer.length % UINT8_BLOCK);
    const paddedBuffer = new Uint8Array(originalBuffer.length + paddingLength);
    paddedBuffer.set(originalBuffer, 0);
    paddedBuffer.fill(paddingLength, originalBuffer.length);
    return paddedBuffer;
  }

  /**
   * depadding the byte array to its original length
   *
   * @param {ByteArray} paddedBuffer
   * @returns {ByteArray}
   * @memberof SM4
   */
  dePadding(paddedBuffer) {
    if (paddedBuffer === null) {
      return null;
    }
    const paddingLength = paddedBuffer[paddedBuffer.length - 1];
    const originalBuffer = paddedBuffer.slice(0, paddedBuffer.length - paddingLength);
    return originalBuffer;
  }

  /**
   * exctract uint32 array block from uint8 array
   *
   * @param {Uint8Array} uint8Array
   * @param {Number} baseIndex
   * @returns {Uint32Array}
   * @memberof SM4
   */
  uint8ToUint32Block(uint8Array, baseIndex = 0) {
    const block = new Uint32Array(4); // make Uint8Array to Uint32Array block
    block[0] =
      (uint8Array[baseIndex] << 24) |
      (uint8Array[baseIndex + 1] << 16) |
      (uint8Array[baseIndex + 2] << 8) |
      uint8Array[baseIndex + 3];
    block[1] =
      (uint8Array[baseIndex + 4] << 24) |
      (uint8Array[baseIndex + 5] << 16) |
      (uint8Array[baseIndex + 6] << 8) |
      uint8Array[baseIndex + 7];
    block[2] =
      (uint8Array[baseIndex + 8] << 24) |
      (uint8Array[baseIndex + 9] << 16) |
      (uint8Array[baseIndex + 10] << 8) |
      uint8Array[baseIndex + 11];
    block[3] =
      (uint8Array[baseIndex + 12] << 24) |
      (uint8Array[baseIndex + 13] << 16) |
      (uint8Array[baseIndex + 14] << 8) |
      uint8Array[baseIndex + 15];
    return block;
  }

  /**
   * encrypt the string plaintext
   *
   * @param {String} plaintext
   * @memberof SM4
   * @return {String} ciphertext
   */
  encrypt(plaintext) {
    const plainByteArray = Crypt.stringToArrayBufferInUtf8(plaintext);
    const padded = this.padding(plainByteArray);
    const blockTimes = padded.length / UINT8_BLOCK;
    const outArray = new Uint8Array(padded.length);
    if (this.mode === 'cbc') {
      // CBC mode
      if (this.iv === null || this.iv.length !== 16) {
        throw new Error('iv error');
      }
      // init chain with iv (transform to uint32 block)
      let chainBlock = this.uint8ToUint32Block(this.iv);
      for (let i = 0; i < blockTimes; i++) {
        // extract the 16 bytes block data for this round to encrypt
        const roundIndex = i * UINT8_BLOCK;
        const block = this.uint8ToUint32Block(padded, roundIndex);
        // xor the chain block
        chainBlock[0] ^= block[0];
        chainBlock[1] ^= block[1];
        chainBlock[2] ^= block[2];
        chainBlock[3] ^= block[3];
        // use chain block to crypt
        const cipherBlock = this.doBlockCrypt(chainBlock, this.encryptRoundKeys);
        // make the cipher block be part of next chain block
        chainBlock = cipherBlock;
        for (let l = 0; l < UINT8_BLOCK; l++) {
          outArray[roundIndex + l] = (cipherBlock[parseInt(l / 4)] >> (((3 - l) % 4) * 8)) & 0xff;
        }
      }
    } else {
      // this will be ECB mode
      for (let i = 0; i < blockTimes; i++) {
        // extract the 16 bytes block data for this round to encrypt
        const roundIndex = i * UINT8_BLOCK;
        const block = this.uint8ToUint32Block(padded, roundIndex);
        const cipherBlock = this.doBlockCrypt(block, this.encryptRoundKeys);
        for (let l = 0; l < UINT8_BLOCK; l++) {
          outArray[roundIndex + l] = (cipherBlock[parseInt(l / 4)] >> (((3 - l) % 4) * 8)) & 0xff;
        }
      }
    }

    // cipher array to string
    if (this.cipherType === 'base64') {
      return Crypt.arrayBufferToBase64(outArray);
    }
    // text
    return Crypt.utf8ArrayBufferToString(outArray);
  }

  /**
   * decrypt the string ciphertext
   *
   * @param {String} ciphertext
   * @memberof SM4
   */
  decrypt(ciphertext) {
    // get cipher byte array
    let cipherByteArray = new Uint8Array();
    if (this.cipherType === 'base64') {
      // cipher is base64 string
      cipherByteArray = Crypt.base64ToArrayBuffer(ciphertext);
    } else {
      // cipher is text
      cipherByteArray = Crypt.stringToArrayBufferInUtf8(ciphertext);
    }
    const blockTimes = cipherByteArray.length / UINT8_BLOCK;
    const outArray = new Uint8Array(cipherByteArray.length);
    // decrypt the ciphertext by block
    if (this.mode === 'cbc') {
      // todo CBC mode
      if (this.iv === null || this.iv.length !== 16) {
        throw new Error('iv error');
      }
      // init chain with iv (transform to uint32 block)
      let chainBlock = this.uint8ToUint32Block(this.iv);
      for (let i = 0; i < blockTimes; i++) {
        // extract the 16 bytes block data for this round to encrypt
        const roundIndex = i * UINT8_BLOCK;
        // make Uint8Array to Uint32Array block
        const block = this.uint8ToUint32Block(cipherByteArray, roundIndex);
        // reverse the round keys to decrypt
        const plainBlockBeforeXor = this.doBlockCrypt(block, this.decryptRoundKeys);
        // xor the chain block
        const plainBlock = new Uint32Array(4);
        plainBlock[0] = chainBlock[0] ^ plainBlockBeforeXor[0];
        plainBlock[1] = chainBlock[1] ^ plainBlockBeforeXor[1];
        plainBlock[2] = chainBlock[2] ^ plainBlockBeforeXor[2];
        plainBlock[3] = chainBlock[3] ^ plainBlockBeforeXor[3];
        // make the cipher block be part of next chain block
        chainBlock = block;
        for (let l = 0; l < UINT8_BLOCK; l++) {
          outArray[roundIndex + l] = (plainBlock[parseInt(l / 4)] >> (((3 - l) % 4) * 8)) & 0xff;
        }
      }
    } else {
      // ECB mode
      for (let i = 0; i < blockTimes; i++) {
        // extract the 16 bytes block data for this round to encrypt
        const roundIndex = i * UINT8_BLOCK;
        // make Uint8Array to Uint32Array block
        const block = this.uint8ToUint32Block(cipherByteArray, roundIndex);
        // reverse the round keys to decrypt
        const plainBlock = this.doBlockCrypt(block, this.decryptRoundKeys);
        for (let l = 0; l < UINT8_BLOCK; l++) {
          outArray[roundIndex + l] = (plainBlock[parseInt(l / 4)] >> (((3 - l) % 4) * 8)) & 0xff;
        }
      }
    }
    // depadding the decrypted data
    const depaddedPlaintext = this.dePadding(outArray);
    // transform data to utf8 string
    return Crypt.utf8ArrayBufferToString(depaddedPlaintext);
  }
}

export default SM4;
