#include "aes_crypt.h"
#include <QtCore/QByteArray>
#include <openssl/evp.h>
#include <openssl/err.h>
#include <NGLLogger/NGLLoggerBootstrap.h>

namespace LtsLicence
{
struct AesCryptPrivate
{
  AesCryptPrivate()
    : passPhrase(QLatin1String("LTS " LTS_VERSION_MAJOR "." LTS_VERSION_MINOR))
    , logger(NGL::NGLLoggerBootstrap::getNGLRootLogger().getNGLLogger("LtsLicenceLib.AesCrypt"))
  {
    qsrand(time(nullptr));
#if OPENSSL_VERSION_NUMBER < 0x1010000fL
    ERR_load_crypto_strings();
#endif
  }
  ~AesCryptPrivate()
  {
#if OPENSSL_VERSION_NUMBER < 0x1010000fL
    ERR_free_strings();
#endif
  }

  QString passPhrase;
  NGL::INGLLogger &logger;
};
Q_GLOBAL_STATIC(AesCryptPrivate, s_Private)

void setPassPhrase(const QString &passPhrase)
{
  s_Private->passPhrase = passPhrase;
}

QString passPhrase()
{
  return s_Private->passPhrase;
}

QByteArray decryptData(const QByteArray &dataToDecrypt,
                       const QString &pw,
                       bool *bOk)
{
  if (bOk)
    *bOk = false;

  int ret;
  int outSize1 = 0;
  int outSize2 = 0;
  unsigned char key[32];

  
  const QByteArray baPassword = pw.toUtf8();
  const unsigned char *dataPw = reinterpret_cast<const unsigned char *>(baPassword.data());
  int i = EVP_BytesToKey(EVP_aes_256_cbc(),
                         EVP_sha1(),
                         nullptr,
                         dataPw,
                         baPassword.size(),
                         5,
                         key,
                         nullptr);
  if (i != 32)
  {
    ERROR_LOG(s_Private->logger) << "Wrong key size - should be 256 bits" ;
    return QByteArray();
  }

  const QByteArray baSalt = dataToDecrypt.left(EVP_MAX_IV_LENGTH);
  const unsigned char *salt = reinterpret_cast<const unsigned char *>(baSalt.data());

  const QByteArray bufEncrypted = dataToDecrypt.mid(EVP_MAX_IV_LENGTH);

  EVP_CIPHER_CTX *ctx = EVP_CIPHER_CTX_new();
  ret = EVP_DecryptInit_ex(ctx,
                           EVP_aes_256_cbc(),
                           nullptr,
                           key,
                           salt);
  if (ret == 0)
  {
    EVP_CIPHER_CTX_free(ctx);
    char errbuf[256];
    ERR_error_string_n(ERR_get_error(), errbuf, sizeof(errbuf));
    ERROR_LOG(s_Private->logger) << "EVP_DecryptInit_ex failed" ;
    return QByteArray();
  }

  
  QByteArray bufDecrypted;
  bufDecrypted.resize(bufEncrypted.size() + EVP_CIPHER_CTX_block_size(ctx));
  const unsigned char *dataIn = reinterpret_cast<const unsigned char *>(bufEncrypted.data());
  unsigned char *dataOut = reinterpret_cast<unsigned char *>(bufDecrypted.data());

  ret = EVP_DecryptUpdate(ctx,
                          dataOut,
                          &outSize1,
                          dataIn,
                          bufEncrypted.size());
  if (ret == 0)
  {
    EVP_CIPHER_CTX_free(ctx);
    char errbuf[256];
    ERR_error_string_n(ERR_get_error(), errbuf, sizeof(errbuf));
    ERROR_LOG(s_Private->logger) << "EVP_DecryptUpdate failed" ;
    return QByteArray();
  }

  ret = EVP_DecryptFinal_ex(ctx,
                            dataOut + outSize1,
                            &outSize2);
  if (ret == 0)
  {
    EVP_CIPHER_CTX_free(ctx);
    char errbuf[256];
    ERR_error_string_n(ERR_get_error(), errbuf, sizeof(errbuf));
    ERROR_LOG(s_Private->logger) << "EVP_DecryptFinal_ex failed" ;
    return QByteArray();
  }

  EVP_CIPHER_CTX_free(ctx);

  bufDecrypted.resize(outSize1 + outSize2);

  if (bOk)
    *bOk = true;
  return bufDecrypted;
}


QByteArray encryptData(const QByteArray &dataToEncrypt,
                       const QString &pw,
                       bool *bOk)
{
  if (bOk)
    *bOk = false;

  int ret;
  int outSize1 = 0;
  int outSize2 = 0;
  unsigned char key[32];
  QByteArray bufEncrypted;

  
  const QByteArray baPassword = pw.toUtf8();
  const unsigned char *dataPw = reinterpret_cast<const unsigned char *>(baPassword.data());
  int i = EVP_BytesToKey(EVP_aes_256_cbc(),
                         EVP_sha1(),
                         nullptr,
                         dataPw,
                         baPassword.size(),
                         5,
                         key,
                         nullptr);
  if (i != 32)
  {
    ERROR_LOG(s_Private->logger) << "Wrong key size - should be 256 bits" ;
    return QByteArray();
  }

  
  QByteArray baSalt(EVP_MAX_IV_LENGTH, 0);
  for (int i = 0; i < EVP_MAX_IV_LENGTH; ++i)
    baSalt[i] = qrand();
  const unsigned char *salt = reinterpret_cast<const unsigned char *>(baSalt.data());

  
  EVP_CIPHER_CTX *ctx = EVP_CIPHER_CTX_new();
  ret = EVP_EncryptInit_ex(ctx,
                           EVP_aes_256_cbc(),
                           nullptr,
                           key,
                           salt);
  if (ret == 0)
  {
    EVP_CIPHER_CTX_free(ctx);
    char errbuf[256];
    ERR_error_string_n(ERR_get_error(), errbuf, sizeof(errbuf));
    ERROR_LOG(s_Private->logger) << "EVP_EncryptInit_ex failed" ;
    return QByteArray();
  }

  
  bufEncrypted = QByteArray::fromRawData(reinterpret_cast<const char *>(salt), EVP_MAX_IV_LENGTH);
  bufEncrypted.resize(bufEncrypted.size() +
                      dataToEncrypt.size() +
                      EVP_CIPHER_CTX_block_size(ctx));
  const unsigned char *dataIn = reinterpret_cast<const unsigned char *>(dataToEncrypt.data());
  unsigned char *dataOut = reinterpret_cast<unsigned char *>(bufEncrypted.data());
  dataOut += baSalt.size();
  ret = EVP_EncryptUpdate(ctx,
                          dataOut,
                          &outSize1,
                          dataIn,
                          dataToEncrypt.size());
  if (ret == 0)
  {
    EVP_CIPHER_CTX_free(ctx);
    char errbuf[256];
    ERR_error_string_n(ERR_get_error(), errbuf, sizeof(errbuf));
    ERROR_LOG(s_Private->logger) << "EVP_EncryptUpdate failed" ;
    return QByteArray();
  }

  
  ret = EVP_EncryptFinal_ex(ctx,
                            dataOut + outSize1,
                            &outSize2);
  if (ret == 0)
  {
    EVP_CIPHER_CTX_free(ctx);
    char errbuf[256];
    ERR_error_string_n(ERR_get_error(), errbuf, sizeof(errbuf));
    ERROR_LOG(s_Private->logger) << "EVP_EncryptFinal_ex failed" ;
    return QByteArray();
  }
  
  EVP_CIPHER_CTX_free(ctx);

  bufEncrypted.resize(outSize1 + outSize2 + baSalt.size());

  if (bOk)
    *bOk = true;
  return bufEncrypted;
}

}