/**
 * Copyright (C) 2021 Saturneric <eric@bktus.com>
 *
 * This file is part of GpgFrontend.
 *
 * GpgFrontend is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * GpgFrontend is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with GpgFrontend. If not, see <https://www.gnu.org/licenses/>.
 *
 * The initial version of the source code is inherited from
 * the gpg4usb project, which is under GPL-3.0-or-later.
 *
 * All the source code of GpgFrontend was modified and released by
 * Saturneric <eric@bktus.com> starting on May 12, 2021.
 *
 * SPDX-License-Identifier: GPL-3.0-or-later
 *
 */

#include "KeyPackageOperator.h"

#include <qt-aes/qaesencryption.h>

#include <boost/format.hpp>

#include "core/function/KeyPackageOperator.h"
#include "core/function/PassphraseGenerator.h"
#include "core/function/gpg/GpgKeyGetter.h"
#include "core/function/gpg/GpgKeyImportExporter.h"
#include "core/typedef/CoreTypedef.h"
#include "core/utils/GpgUtils.h"
#include "core/utils/IOUtils.h"

namespace GpgFrontend {

auto KeyPackageOperator::GeneratePassphrase(
    const std::filesystem::path& phrase_path, std::string& phrase) -> bool {
  phrase = PassphraseGenerator::GetInstance().Generate(256);
  GF_CORE_LOG_DEBUG("generated passphrase: {} bytes", phrase.size());
  return WriteFileStd(phrase_path, phrase);
}

void KeyPackageOperator::GenerateKeyPackage(
    const std::filesystem::path& key_package_path,
    const std::string& key_package_name, const KeyArgsList& keys,
    std::string& phrase, bool secret, const OperationCallback& cb) {
  GF_CORE_LOG_DEBUG("generating key package: {}", key_package_name);

  GpgKeyImportExporter::GetInstance().ExportKeys(
      keys, secret, true, false, false,
      [=](GpgError err, const DataObjectPtr& data_obj) {
        if (CheckGpgError(err) != GPG_ERR_NO_ERROR) {
          GF_LOG_ERROR("export keys error, reason: {}",
                       DescribeGpgErrCode(err).second);
          cb(-1, data_obj);
          return;
        }

        if (data_obj == nullptr || !data_obj->Check<GFBuffer>()) {
          throw std::runtime_error("data object doesn't pass checking");
        }

        auto gf_buffer = ExtractParams<GFBuffer>(data_obj, 0);
        auto key = QByteArray::fromStdString(phrase);
        auto data = gf_buffer.ConvertToQByteArray().toBase64();
        auto hash_key =
            QCryptographicHash::hash(key, QCryptographicHash::Sha256);
        QAESEncryption encryption(QAESEncryption::AES_256, QAESEncryption::ECB,
                                  QAESEncryption::Padding::ISO);
        auto encoded_data = encryption.encode(data, hash_key);
        GF_CORE_LOG_DEBUG("writing key package, name: {}", key_package_name);

        cb(WriteFileStd(key_package_path, encoded_data.toStdString()) ? 0 : -1,
           TransferParams());
        return;
      });
}

auto KeyPackageOperator::ImportKeyPackage(
    const std::filesystem::path& key_package_path,
    const std::filesystem::path& phrase_path)
    -> std::tuple<bool, std::shared_ptr<GpgImportInformation>> {
  GF_CORE_LOG_DEBUG("importing key package: {}", key_package_path.u8string());

  std::string encrypted_data;
  ReadFileStd(key_package_path, encrypted_data);

  if (encrypted_data.empty()) {
    GF_CORE_LOG_ERROR("failed to read key package: {}",
                      key_package_path.u8string());
    return {false, nullptr};
  };

  std::string passphrase;
  ReadFileStd(phrase_path, passphrase);
  GF_CORE_LOG_DEBUG("passphrase: {} bytes", passphrase.size());
  if (passphrase.size() != 256) {
    GF_CORE_LOG_ERROR("failed to read passphrase: {}", phrase_path.u8string());
    return {false, nullptr};
  }

  auto hash_key = QCryptographicHash::hash(
      QByteArray::fromStdString(passphrase), QCryptographicHash::Sha256);
  auto encoded = QByteArray::fromStdString(encrypted_data);

  QAESEncryption encryption(QAESEncryption::AES_256, QAESEncryption::ECB,
                            QAESEncryption::Padding::ISO);

  auto decoded = encryption.removePadding(encryption.decode(encoded, hash_key));
  auto key_data = QByteArray::fromBase64(decoded);

  GF_CORE_LOG_DEBUG("import key package, read key data size: {}",
                    key_data.size());
  if (!key_data.startsWith(PGP_PUBLIC_KEY_BEGIN) &&
      !key_data.startsWith(PGP_PRIVATE_KEY_BEGIN)) {
    return {false, nullptr};
  }

  auto import_info =
      GpgKeyImportExporter::GetInstance().ImportKey(GFBuffer(key_data));
  return {true, import_info};
}

auto KeyPackageOperator::GenerateKeyPackageName() -> std::string {
  return generate_key_package_name();
}

/**
 * @brief generate key package name
 *
 * @return std::string key package name
 */
auto KeyPackageOperator::generate_key_package_name() -> std::string {
  std::random_device rd_;          ///< Random device
  auto mt_ = std::mt19937(rd_());  ///< Mersenne twister

  std::uniform_int_distribution<int> dist(999, 99999);
  auto file_string = boost::format("KeyPackage_%1%") % dist(mt_);
  return file_string.str();
}

}  // namespace GpgFrontend