#include "./aes.h"

#include <cstring>

namespace Crypto {

/*!
 * \class Aes
 * \brief The Aes class implements AES encryption/decryption.
 * \deprecated This class is not used by the rest of the library and not compiled by default.
 *             OpenSSL's crypto library is used instead. This class only serves educational
 *             purposes.
 */

// clang-format off
Aes::byte Aes::sbox[16][16] = {
    { 0x63, 0x7C, 0x77, 0x7B, 0xF2, 0x6B, 0x6F, 0xC5, 0x30, 0x01, 0x67, 0x2B, 0xFE, 0xD7, 0xAB, 0x76 },
    { 0xCA, 0x82, 0xC9, 0x7D, 0xFA, 0x59, 0x47, 0xF0, 0xAD, 0xD4, 0xA2, 0xAF, 0x9C, 0xA4, 0x72, 0xC0 },
    { 0xB7, 0xFD, 0x93, 0x26, 0x36, 0x3F, 0xF7, 0xCC, 0x34, 0xA5, 0xE5, 0xF1, 0x71, 0xD8, 0x31, 0x15 },
    { 0x04, 0xC7, 0x23, 0xC3, 0x18, 0x96, 0x05, 0x9A, 0x07, 0x12, 0x80, 0xE2, 0xEB, 0x27, 0xB2, 0x75 },
    { 0x09, 0x83, 0x2C, 0x1A, 0x1B, 0x6E, 0x5A, 0xA0, 0x52, 0x3B, 0xD6, 0xB3, 0x29, 0xE3, 0x2F, 0x84 },
    { 0x53, 0xD1, 0x00, 0xED, 0x20, 0xFC, 0xB1, 0x5B, 0x6A, 0xCB, 0xBE, 0x39, 0x4A, 0x4C, 0x58, 0xCF },
    { 0xD0, 0xEF, 0xAA, 0xFB, 0x43, 0x4D, 0x33, 0x85, 0x45, 0xF9, 0x02, 0x7F, 0x50, 0x3C, 0x9F, 0xA8 },
    { 0x51, 0xA3, 0x40, 0x8F, 0x92, 0x9D, 0x38, 0xF5, 0xBC, 0xB6, 0xDA, 0x21, 0x10, 0xFF, 0xF3, 0xD2 },
    { 0xCD, 0x0C, 0x13, 0xEC, 0x5F, 0x97, 0x44, 0x17, 0xC4, 0xA7, 0x7E, 0x3D, 0x64, 0x5D, 0x19, 0x73 },
    { 0x60, 0x81, 0x4F, 0xDC, 0x22, 0x2A, 0x90, 0x88, 0x46, 0xEE, 0xB8, 0x14, 0xDE, 0x5E, 0x0B, 0xDB },
    { 0xE0, 0x32, 0x3A, 0x0A, 0x49, 0x06, 0x24, 0x5C, 0xC2, 0xD3, 0xAC, 0x62, 0x91, 0x95, 0xE4, 0x79 },
    { 0xE7, 0xC8, 0x37, 0x6D, 0x8D, 0xD5, 0x4E, 0xA9, 0x6C, 0x56, 0xF4, 0xEA, 0x65, 0x7A, 0xAE, 0x08 },
    { 0xBA, 0x78, 0x25, 0x2E, 0x1C, 0xA6, 0xB4, 0xC6, 0xE8, 0xDD, 0x74, 0x1F, 0x4B, 0xBD, 0x8B, 0x8A },
    { 0x70, 0x3E, 0xB5, 0x66, 0x48, 0x03, 0xF6, 0x0E, 0x61, 0x35, 0x57, 0xB9, 0x86, 0xC1, 0x1D, 0x9E },
    { 0xE1, 0xF8, 0x98, 0x11, 0x69, 0xD9, 0x8E, 0x94, 0x9B, 0x1E, 0x87, 0xE9, 0xCE, 0x55, 0x28, 0xDF },
    { 0x8C, 0xA1, 0x89, 0x0D, 0xBF, 0xE6, 0x42, 0x68, 0x41, 0x99, 0x2D, 0x0F, 0xB0, 0x54, 0xBB, 0x16 }
};

Aes::byte Aes::inv_sbox[16][16] = {
    { 0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb },
    { 0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb },
    { 0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e },
    { 0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25 },
    { 0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92 },
    { 0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84 },
    { 0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06 },
    { 0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b },
    { 0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73 },
    { 0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e },
    { 0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b },
    { 0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4 },
    { 0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f },
    { 0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef },
    { 0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61 },
    { 0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d }
};

Aes::word Aes::rcon[52] = {
    0x00000000, 0x01000000, 0x02000000, 0x04000000, 0x08000000, 0x10000000, 0x20000000, 0x40000000,
    0x80000000, 0x1B000000, 0x36000000, 0x6C000000, 0xD8000000, 0xAB000000, 0x4D000000, 0x9A000000,
    0x2F000000, 0x5E000000, 0xBC000000, 0x63000000, 0xC6000000, 0x97000000, 0x35000000, 0x6A000000,
    0xD4000000, 0xB3000000, 0x7D000000, 0xFA000000, 0xEF000000, 0xC5000000, 0x91000000, 0x39000000,
    0x72000000, 0xE4000000, 0xD3000000, 0xBD000000, 0x61000000, 0xC2000000, 0x9F000000, 0x25000000,
    0x4A000000, 0x94000000, 0x33000000, 0x66000000, 0xCC000000, 0x83000000, 0x1D000000, 0x3A000000,
    0x74000000, 0xE8000000, 0xCB000000, 0x8D000000
};
// clang-format on

Aes::Aes()
    : keyLength(0)
    , numRounds(0)
    , w(0)
{
    memset(state, 0, 16);
}

Aes::~Aes()
{
}

Aes::byte Aes::gmul(byte a, byte b)
{
    unsigned char p = 0;
    unsigned char hi;

    for (byte i = 0; i < 8; ++i) {
        if ((b & 1) == 1)
            p ^= a;
        hi = (a & 0x80);
        a <<= 1;
        if (hi == 0x80)
            a ^= 0x1b;
        b >>= 1;
    }
    return p;
}

void Aes::rotWord(word *b)
{
    byte tmp[4];
    memcpy(tmp, b, 4);

    byte tmpb = tmp[3];

    for (byte i = 3; i > 0; --i)
        tmp[i] = tmp[i - 1];

    tmp[0] = tmpb;

    memcpy(b, tmp, 4);
}

void Aes::subWord(word *b)
{
    byte tmp[4];
    memcpy(tmp, b, 4);

    for (byte i = 0; i < 4; ++i)
        tmp[i] = sbox[tmp[i] >> 4][tmp[i] & 0x0f];

    memcpy(b, tmp, 4);
}

void Aes::expandKey(byte *key)
{
    if (w)
        delete[] w;

    w = new word[4 * (numRounds + 1)];

    for (byte iw = 0, ib = 0; iw < keyLength; ++iw, ib += 4)
        w[iw] = static_cast<word>((key[ib] << 24) + (key[ib + 1] << 16) + (key[ib + 2] << 8) + key[ib + 3]);

    word tmp;

    for (byte i = keyLength; i < (4 * (numRounds + 1)); ++i) {

        tmp = w[i - 1];

        if ((i % keyLength) == 0) {
            rotWord(&tmp);
            subWord(&tmp);
            tmp ^= rcon[i / keyLength];
        } else if ((keyLength > 6) && ((i % keyLength) == 4)) {
            subWord(&tmp);
        }

        w[i] = w[i - keyLength] ^ tmp;
    }
}

void Aes::addRoundKey(byte round)
{
    for (byte col = 0; col < 4; ++col)
        for (byte row = 0; row < 4; ++row)
            state[row][col] ^= static_cast<byte>((w[round * 4 + col] >> (24 - row * 8)) & 0x000000ff);
}

void Aes::shiftRows(void)
{
    byte tmp = 0;
    tmp = state[1][0];
    state[1][0] = state[1][1];
    state[1][1] = state[1][2];
    state[1][2] = state[1][3];
    state[1][3] = tmp;

    tmp = state[2][0];
    state[2][0] = state[2][2];
    state[2][2] = tmp;
    tmp = state[2][1];
    state[2][1] = state[2][3];
    state[2][3] = tmp;

    tmp = state[3][3];
    state[3][3] = state[3][2];
    state[3][2] = state[3][1];
    state[3][1] = state[3][0];
    state[3][0] = tmp;
}

void Aes::invShiftRows(void)
{
    byte tmp = 0;
    tmp = state[3][0];
    state[3][0] = state[3][1];
    state[3][1] = state[3][2];
    state[3][2] = state[3][3];
    state[3][3] = tmp;

    tmp = state[2][0];
    state[2][0] = state[2][2];
    state[2][2] = tmp;
    tmp = state[2][1];
    state[2][1] = state[2][3];
    state[2][3] = tmp;

    tmp = state[1][3];
    state[1][3] = state[1][2];
    state[1][2] = state[1][1];
    state[1][1] = state[1][0];
    state[1][0] = tmp;
}

void Aes::mixColumns(void)
{
    unsigned char a[4];
    unsigned char b[4];
    unsigned char h = 0;

    for (byte col = 0; col < 4; ++col) {
        for (byte row = 0; row < 4; ++row) {
            a[row] = state[row][col];
            h = state[row][col] & 0x80;
            b[row] = static_cast<byte>(state[row][col] << 1);
            if (h == 0x80)
                b[row] ^= 0x1b;
        }
        state[0][col] = b[0] ^ a[3] ^ a[2] ^ b[1] ^ a[1];
        state[1][col] = b[1] ^ a[0] ^ a[3] ^ b[2] ^ a[2];
        state[2][col] = b[2] ^ a[1] ^ a[0] ^ b[3] ^ a[3];
        state[3][col] = b[3] ^ a[2] ^ a[1] ^ b[0] ^ a[0];
    }
}

void Aes::invMixColumns(void)
{
    unsigned char a[4];

    for (byte col = 0; col < 4; ++col) {
        for (byte row = 0; row < 4; ++row)
            a[row] = state[row][col];
        state[0][col] = gmul(a[0], 14) ^ gmul(a[3], 9) ^ gmul(a[2], 13) ^ gmul(a[1], 11);
        state[1][col] = gmul(a[1], 14) ^ gmul(a[0], 9) ^ gmul(a[3], 13) ^ gmul(a[2], 11);
        state[2][col] = gmul(a[2], 14) ^ gmul(a[1], 9) ^ gmul(a[0], 13) ^ gmul(a[3], 11);
        state[3][col] = gmul(a[3], 14) ^ gmul(a[2], 9) ^ gmul(a[1], 13) ^ gmul(a[0], 11);
    }
}

bool Aes::setKey(char *key)
{
    size_t keyLen = strlen(key);

    byte *wKey = 0;
    byte desKeyLen = 0;

    if (keyLen <= 16) {
        keyLength = 4;
        numRounds = 10;
        desKeyLen = 16;

    } else if (keyLen <= 24) {
        keyLength = 6;
        numRounds = 12;
        desKeyLen = 24;

    } else if (keyLen <= 32) {
        keyLength = 8;
        numRounds = 14;
        desKeyLen = 32;
    }

    wKey = new byte[desKeyLen];
    for (byte i = 0, t = 0; t < desKeyLen; ++i, ++t) {
        if (i == keyLen)
            i = 0;
        *(wKey + t) = static_cast<byte>(*(key + i));
    }

    expandKey(wKey);
    delete[] wKey;
    return true;
}

void Aes::cipher(void)
{
    addRoundKey(0);

    for (byte round = 1; round < numRounds; ++round) {
        for (byte row = 0; row < 4; ++row)
            for (byte col = 0; col < 4; ++col)
                state[row][col] = sbox[state[row][col] >> 4][state[row][col] & 0x0f];
        shiftRows();
        mixColumns();
        addRoundKey(round);
    }

    for (byte row = 0; row < 4; ++row)
        for (byte col = 0; col < 4; ++col)
            state[row][col] = sbox[state[row][col] >> 4][state[row][col] & 0x0f];

    shiftRows();
    addRoundKey(numRounds);
}

void Aes::invCipher(void)
{
    addRoundKey(numRounds);

    for (byte round = (numRounds - 1); round > 0; --round) {
        invShiftRows();
        for (byte row = 0; row < 4; ++row)
            for (byte col = 0; col < 4; ++col)
                state[row][col] = inv_sbox[state[row][col] >> 4][state[row][col] & 0x0f];
        addRoundKey(round);
        invMixColumns();
    }

    invShiftRows();

    for (byte row = 0; row < 4; ++row)
        for (byte col = 0; col < 4; ++col)
            state[row][col] = inv_sbox[state[row][col] >> 4][state[row][col] & 0x0f];

    addRoundKey(0);
}

size_t Aes::encrypt(char **data, std::size_t length, char *key)
{
    if (length == 0)
        return 0;

    if (!setKey(key))
        return 0;

    size_t oldLength = length;
    while (length % 16)
        ++length;

    char *buffer = new char[length];
    memset(buffer, 0, length);
    memcpy(buffer, *data, oldLength);

    delete[] * data;
    *data = buffer;

    size_t curBlock = 0;

    do {
        for (byte col = 0; col < 4; ++col)
            for (byte row = 0; row < 4; ++row)
                state[row][col] = static_cast<byte>((*data)[curBlock * 16 + row + 4 * col]);
        cipher();
        for (byte col = 0; col < 4; ++col)
            for (byte row = 0; row < 4; ++row)
                (*data)[curBlock * 16 + row + 4 * col] = static_cast<char>(state[row][col]);
        ++curBlock;
    } while (curBlock * 16 != length);

    return curBlock;
}

size_t Aes::decrypt(char **data, std::size_t length, char *key)
{
    if (length == 0)
        return 0;

    if (!setKey(key))
        return 0;

    std::size_t oldLength = length;
    while (length % 16)
        ++length;

    char *buffer = new char[length];
    memset(buffer, 0, length);
    memcpy(buffer, *data, oldLength);

    delete[] * data;
    *data = buffer;

    std::size_t curBlock = 0;

    do {
        for (byte col = 0; col < 4; ++col)
            for (byte row = 0; row < 4; ++row)
                state[row][col] = static_cast<byte>((*data)[curBlock * 16 + row + 4 * col]);

        invCipher();

        for (byte col = 0; col < 4; ++col)
            for (byte row = 0; row < 4; ++row)
                (*data)[curBlock * 16 + row + 4 * col] = static_cast<char>(state[row][col]);

        ++curBlock;

    } while (curBlock * 16 != length);

    --length;

    while (!(static_cast<decltype(length)>(*buffer) + length))
        --length;

    ++length;

    return length;
}

} // namespace Crypto