#include <openssl/conf.h>
#include <openssl/ssl.h> /* core library */
#include "utils.h"


using namespace std;

const std::string base64_chars =
    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

const char base64_url_alphabet[] = {
    'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
    'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
    'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
    'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
    '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '-', '_'};

void getCharsFromString(string &source, char *charArray, size_t length)
{
  for (size_t i = 0; i < length; i++)
  {
    charArray[i] = source[i];
  }
}

void getCharsFromString(string source, char *charArray)
{
  size_t length = source.length(); 
  for (size_t i = 0; i < length; i++)
  {
    charArray[i] = source[i];
  }
}

std::string right(const std::string &sourceString, size_t numChars)
{
  if (numChars >= sourceString.size())
  {
    return sourceString; // If numChars is greater or equal to the string size, return the whole string.
  }
  return sourceString.substr(sourceString.size() - numChars);
}

uint16_t calculateCRC16(const uint8_t *data, size_t length)
{
  const uint16_t polynomial = 0xA001; // CRC16-CCITT polynomial
  uint16_t crc = 0xFFFF;              // Initial value

  for (size_t i = 0; i < length; i++)
  {
    crc ^= data[i]; // XOR with the current data byte

    for (int j = 0; j < 8; j++)
    {
      if (crc & 0x0001)
      {
        crc = (crc >> 1) ^ polynomial;
      }
      else
      {
        crc = crc >> 1;
      }
    }
  }

  return crc;
}

uint16_t crc16(const unsigned char *data_p, unsigned char length)
{
  uint16_t x;
  uint16_t crc = 0xFFFF;

  while (length--)
  {
    x = crc >> 8 ^ *data_p++;
    x ^= x >> 4;
    crc = (crc << 8) ^ ((unsigned short)(x << 12)) ^ ((unsigned short)(x << 5)) ^ ((unsigned short)x);
  }
  return crc;
}

DATE getLicDate()
{
  time_t ttime = time(0);
  tm *local_time = localtime(&ttime);
  int hoursSeconds = 3600 * local_time->tm_hour;
  int minutesSeconds = 60 * local_time->tm_min;
  int seconds = 1 * local_time->tm_sec;
  int totalSeconds = hoursSeconds + minutesSeconds + seconds;

#ifdef WINDOWS
  DATE dateOnly = ttime - totalSeconds + 7200; // (pro windows); // 7200 + vteřina za dvě hodiny pro srování
#else
  DATE dateOnly = ttime - totalSeconds;
#endif

  return dateOnly;
}

string getDate()
{
  auto r = std::chrono::system_clock::now();
  auto rp = std::chrono::system_clock::to_time_t(r);
  std::string h(ctime(&rp)); // converting to c++ string
  return h;
}

int encrypt(const unsigned char *plaintext, int plaintext_len, unsigned char *key,
            unsigned char *iv, unsigned char *ciphertext)
{
  EVP_CIPHER_CTX *ctx;

  int len;

  int ciphertext_len;

  /* Create and initialise the context */
  if (!(ctx = EVP_CIPHER_CTX_new())) return -1;
    

  /*
   * Initialise the encryption operation. IMPORTANT - ensure you use a key
   * and IV size appropriate for your cipher
   * In this example we are using 256 bit AES (i.e. a 256 bit key). The
   * IV size for *most* modes is the same as the block size. For AES this
   * is 128 bits
   */
  if (1 != EVP_EncryptInit_ex(ctx, EVP_aes_256_cbc(), NULL, key, iv))
    return -1;

  /*
   * Provide the message to be encrypted, and obtain the encrypted output.
   * EVP_EncryptUpdate can be called multiple times if necessary
   */
  if (1 != EVP_EncryptUpdate(ctx, ciphertext, &len, plaintext, plaintext_len))
    return -1;
  ciphertext_len = len;

  /*
   * Finalise the encryption. Further ciphertext bytes may be written at
   * this stage.
   */
  if (1 != EVP_EncryptFinal_ex(ctx, ciphertext + len, &len))
    return -1;
  ciphertext_len += len;

  /* Clean up */
  EVP_CIPHER_CTX_free(ctx);

  return ciphertext_len;
}

int decrypt(const unsigned char *ciphertext, int ciphertext_len, unsigned char *key,
            unsigned char *iv, unsigned char *plaintext)
{
  EVP_CIPHER_CTX *ctx;

  int len;

  int plaintext_len;

  /* Create and initialise the context */
  if (!(ctx = EVP_CIPHER_CTX_new()))
    return -1;

  /*
   * Initialise the decryption operation. IMPORTANT - ensure you use a key
   * and IV size appropriate for your cipher
   * In this example we are using 256 bit AES (i.e. a 256 bit key). The
   * IV size for *most* modes is the same as the block size. For AES this
   * is 128 bits
   */
  if (1 != EVP_DecryptInit_ex(ctx, EVP_aes_256_cbc(), NULL, key, iv))
    return -1;

  /*
   * Provide the message to be decrypted, and obtain the plaintext output.
   * EVP_DecryptUpdate can be called multiple times if necessary.
   */
  if (1 != EVP_DecryptUpdate(ctx, plaintext, &len, ciphertext, ciphertext_len))
        return -1;
  plaintext_len = len;

  /*
   * Finalise the decryption. Further plaintext bytes may be written at
   * this stage.
   */
  if (1 != EVP_DecryptFinal_ex(ctx, plaintext + len, &len))
        return -1;

  plaintext_len += len;

  /* Clean up */
  EVP_CIPHER_CTX_free(ctx);

  return plaintext_len;
}

// converts character array
// to string and returns it
string convertToString(char *a, int size)
{
  int i;
  string s = "";
  for (i = 0; i < size; i++)
  {
    s = s + a[i];
  }
  return s;
}

std::string base64_decode(const std::string &in)
{
  std::string out;
  std::vector<int> T(256, -1);
  unsigned int i;
  for (i = 0; i < 64; i++)
    T[base64_url_alphabet[i]] = i;

  int val = 0, valb = -8;
  for (i = 0; i < in.length(); i++)
  {
    unsigned char c = in[i];
    if (T[c] == -1)
      break;
    val = (val << 6) + T[c];
    valb += 6;
    if (valb >= 0)
    {
      out.push_back(char((val >> valb) & 0xFF));
      valb -= 8;
    }
  }
  return out;
}

std::string base64_encode_ai(const std::string &input)
{
  std::string encoded;

  size_t input_length = input.length();
  size_t i = 0;

  while (i < input_length)
  {
    unsigned char input_chunk[3] = {0};
    size_t chunk_size = 0;

    // Fill the input chunk with up to 3 bytes from the input string
    for (size_t j = 0; j < 3; ++j)
    {
      if (i < input_length)
      {
        input_chunk[j] = input[i++];
        ++chunk_size;
      }
    }

    // Encode the input chunk into 4 Base64 characters
    encoded += base64_chars[(input_chunk[0] & 0xFC) >> 2];
    encoded += base64_chars[((input_chunk[0] & 0x03) << 4) |
                            ((input_chunk[1] & 0xF0) >> 4)];
    encoded += (chunk_size > 1)
                   ? base64_chars[((input_chunk[1] & 0x0F) << 2) |
                                  ((input_chunk[2] & 0xC0) >> 6)]
                   : '=';
    encoded += (chunk_size > 2)
                   ? base64_chars[input_chunk[2] & 0x3F]
                   : '=';
  }

  return encoded;
}

unordered_map<string, string> getArguments(int argc, char *argv[])
{
  const char splitChar = '=';
  unordered_map<string, string> result;
  if (argc <= 1)
    return result;

  for (int i = 1; i < argc; ++i)
  {
    bool isArgName = true;
    int argLength = strlen(argv[i]);
    string argName;
    string argValue;

    for (int j = 0; j < argLength; j++)
    {
      if (argv[i][j] == splitChar)
      {
        isArgName = false;
        continue;
      }

      if (isArgName)
      {
        argName += argv[i][j];
      }
      else
      {
        argValue += argv[i][j];
      }
    }

    result.insert(make_pair(argName, argValue));
  }
  return result;
}

string getCompletePath(string fileName)
{
#ifdef WINDOWS
  return fileName;
#else
//warning TODO filesystem
char path[PATH_MAX+1] = {};
    ssize_t length = readlink("/proc/self/exe", path, PATH_MAX);
    path[length] = '\0';
    string result = string(dirname(path)) + "/" + fileName;
    return result;
  //return std::string( result, (count > 0) ? count : 0 );
  // std::filesystem::path exePath = std::filesystem::canonical("/proc/self/exe"); // / std::filesystem::path(argv[0]));
  // std::filesystem::path fullPathOther = exePath.parent_path() / fileName;
  // std::string fullPathStrOther = fullPathOther.string();
  // return fullPathStrOther;
#endif
}

void appendStringToVector(const std::string &str, std::vector<unsigned char> &charVector)
{
  size_t strLength = str.length();
  for (size_t i = 0; i < strLength; ++i)
  {
    charVector.push_back(static_cast<unsigned char>(str[i]));
  }
}

uint16_t calculateCRC16(std::vector<unsigned char> &charVector)
{
  const uint16_t polynomial = 0xA001; // CRC16-CCITT polynomial
  uint16_t crc = 0xFFFF;              // Initial value

  size_t length = charVector.size();

  for (size_t i = 0; i < length; i++)
  {
    crc ^= charVector[i]; // XOR with the current data byte

    for (int j = 0; j < 8; j++)
    {
      if (crc & 0x0001)
      {
        crc = (crc >> 1) ^ polynomial;
      }
      else
      {
        crc = crc >> 1;
      }
    }
  }

  return crc;
}

uint32_t bytesToDword(uint8_t byte1, uint8_t byte2, uint8_t byte3, uint8_t byte4)
{
  return static_cast<uint32_t>(byte1) |
         (static_cast<uint32_t>(byte2) << 8) |
         (static_cast<uint32_t>(byte3) << 16) |
         (static_cast<uint32_t>(byte4) << 24);
}

uint32_t bytesToWord(uint8_t byte1, uint8_t byte2)
{
  return static_cast<uint32_t>(byte1) | (static_cast<uint32_t>(byte2) << 8);
}

std::vector<unsigned char> joinVectors(const std::vector<unsigned char> &vector1, const std::vector<unsigned char> &vector2)
{
  std::vector<unsigned char> result;
  result.insert(result.end(), vector1.begin(), vector1.end());
  result.insert(result.end(), vector2.begin(), vector2.end());
  return result;
}

bool readFile(string fileName, vector<char> &output)
{
  std::ifstream file(fileName, std::ios::in | std::ios::binary);
  
  if (file.is_open() != 1)
  {
    return false;
  }

  char byte;
  while (file.get(byte))
  {
    // Convert the char to unsigned char and push it into the vector
    output.push_back(byte);
  }

  file.close();

  return true;
}