/*
 * LibrePCB - Professional EDA for everyone!
 * Copyright (C) 2013 LibrePCB Developers, see AUTHORS.md for contributors.
 * https://librepcb.org/
 *
 * This program 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.
 *
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/*******************************************************************************
 *  Includes
 ******************************************************************************/
#include "filedownload.h"

#include "../exceptions.h"
#include "../fileio/ziparchive.h"
#include "../utils/scopeguard.h"

#include <QtCore>

/*******************************************************************************
 *  Namespace
 ******************************************************************************/
namespace librepcb {

/*******************************************************************************
 *  Constructors / Destructor
 ******************************************************************************/

FileDownload::FileDownload(const QUrl& url, const FilePath& dest) noexcept
  : NetworkRequestBase(url),
    mDestination(dest),
    mHashAlgorithm(QCryptographicHash::Md5),
    mExpectedChecksum(),
    mExtractZipToDir() {
}

FileDownload::~FileDownload() noexcept {
}

/*******************************************************************************
 *  Public Methods
 ******************************************************************************/

void FileDownload::setExpectedChecksum(QCryptographicHash::Algorithm algorithm,
                                       const QByteArray& checksum) noexcept {
  Q_ASSERT(!mStarted);
  mHashAlgorithm = algorithm;
  mExpectedChecksum = checksum;
}

void FileDownload::setZipExtractionDirectory(const FilePath& dir) noexcept {
  Q_ASSERT(!mStarted);
  mExtractZipToDir = dir;
}

/*******************************************************************************
 *  Private Methods
 ******************************************************************************/

void FileDownload::prepareRequest() {
  // check destination filepath
  if (mDestination.isExistingFile() || mDestination.isExistingDir()) {
    throw RuntimeError(__FILE__, __LINE__,
                       QString("The destination file exists already: %1")
                           .arg(mDestination.toNative()));
  }

  // create destination directory
  if (!mDestination.getParentDir().isEmptyDir()) {
    if (!QDir().mkpath(mDestination.getParentDir().toStr())) {
      throw RuntimeError(__FILE__, __LINE__,
                         QString("Could not create directory \"%1\".")
                             .arg(mDestination.getParentDir().toNative()));
    }
  }

  // open temporary destination file
  mFile.reset(new QSaveFile(mDestination.toStr(), this));
  if (!mFile->open(QIODevice::WriteOnly)) {
    throw RuntimeError(__FILE__, __LINE__,
                       QString("Could not open file \"%1\": %2")
                           .arg(mDestination.toNative(), mFile->errorString()));
  }
}

void FileDownload::finalizeRequest() {
  // check destination filepath again
  if (mDestination.isExistingFile() || mDestination.isExistingDir()) {
    throw RuntimeError(__FILE__, __LINE__,
                       QString("The destination file exists already: %1")
                           .arg(mDestination.toNative()));
  }

  // save to destination file
  if (!mFile->commit()) {
    throw RuntimeError(__FILE__, __LINE__,
                       tr("Error while writing file \"%1\": %2")
                           .arg(mDestination.toNative(), mFile->errorString()));
  }

  // if an error occurs below this line, remove the downloaded file
  auto sg = scopeGuard([this]() { QFile::remove(mDestination.toStr()); });

  // verify checksum of downloaded file
  if (!mExpectedChecksum.isEmpty()) {
    emit progressState(tr("Verify checksum..."));
    QFile file(mDestination.toStr());
    if (!file.open(QFile::ReadOnly)) {
      throw RuntimeError(__FILE__, __LINE__,
                         tr("Error while readback file \"%1\": %2")
                             .arg(mDestination.toNative(), file.errorString()));
    }
    QCryptographicHash hash(mHashAlgorithm);
    hash.addData(&file);
    QString result = hash.result().toHex();
    QString expected = mExpectedChecksum.toHex();
    if (result != expected) {
      qDebug().nospace() << "Expected checksum " << expected << " but got "
                         << result << ".";
      throw RuntimeError(
          __FILE__, __LINE__,
          tr("Checksum verification of downloaded file failed!"));
    } else {
      qDebug() << "Checksum verification of downloaded file was successful.";
    }
  }

  // extract zip file if necessary
  if (mExtractZipToDir.isValid()) {
    emit progressState(tr("Extract files..."));
    ZipArchive zip(mDestination);  // can throw
    zip.extractTo(mExtractZipToDir);  // can throw
  } else {
    // do NOT remove the downloaded file
    sg.dismiss();
  }
}

void FileDownload::emitSuccessfullyFinishedSignals(
    QString contentType) noexcept {
  Q_UNUSED(contentType);
  emit fileDownloaded(mDestination);
  if (mExtractZipToDir.isValid()) {
    emit zipFileExtracted(mExtractZipToDir);
  }
}

void FileDownload::fetchNewData(QIODevice& device) noexcept {
  mFile->write(device.readAll());
}

/*******************************************************************************
 *  End of File
 ******************************************************************************/

}  // namespace librepcb
