Downloadable_SingleFile.h

/***************************************************************************
 *   Copyright (C) 2019-2024 by Stefan Kebekus                             *
 *   stefan.kebekus@gmail.com                                              *
 *                                                                         *
 *   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, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/
 
#pragma once
 
#include <QDateTime>
#include <QFile>
#include <QFileInfo>
#include <QNetworkReply>
#include <QPointer>
#include <QQmlEngine>
#include <QSaveFile>
 
#include "Downloadable_Abstract.h"
 
namespace DataManagement
{

 
class Downloadable_SingleFile : public Downloadable_Abstract
{
    Q_OBJECT
    QML_ELEMENT
    QML_UNCREATABLE("")
 
public:
    explicit Downloadable_SingleFile(QUrl url, const QString& localFileName, const QGeoRectangle& bBox = {}, QObject* parent = nullptr);

    ~Downloadable_SingleFile() override;
 
 
 
    //
    // Properties
    //
 
    // Repeated from Downloadable_Abstract to keep QML happy
    Q_PROPERTY(bool downloading READ downloading NOTIFY downloadingChanged)
    Q_PROPERTY(bool hasFile READ hasFile BINDABLE bindableHasFile NOTIFY hasFileChanged)
 
    
    Q_PROPERTY(int downloadProgress READ downloadProgress NOTIFY downloadProgressChanged)

    Q_PROPERTY(QString fileName READ fileName CONSTANT)

    Q_PROPERTY(QByteArray fileContent READ fileContent NOTIFY fileContentChanged)

    Q_PROPERTY(QDateTime remoteFileDate READ remoteFileDate WRITE setRemoteFileDate NOTIFY remoteFileDateChanged)

    Q_PROPERTY(qint64 remoteFileSize READ remoteFileSize WRITE setRemoteFileSize NOTIFY remoteFileSizeChanged)

    Q_PROPERTY(QUrl url READ url CONSTANT)
 
 
 
    //
    // Getter Methods
    //

    [[nodiscard]] auto description() -> QString override;

    [[nodiscard]] auto downloading() -> bool override { return !m_networkReplyDownloadFile.isNull(); }

    [[nodiscard]] auto downloadProgress() const -> int { return m_downloadProgress; }

    [[nodiscard]] auto fileName() const -> QString { return m_fileName; }

    [[nodiscard]] auto fileContent() const -> QByteArray;

    [[nodiscard]] auto files() -> QStringList override;

    [[nodiscard]] auto infoText() -> QString override;

    [[nodiscard]] auto remoteFileDate() const -> QDateTime { return m_remoteFileDate; }

    [[nodiscard]] auto remoteFileSize() -> qint64 override { return m_remoteFileSize; }

    [[nodiscard]] auto updateSize() -> Units::ByteSize override;

    [[nodiscard]] auto url() const -> QUrl { return m_url; }
 
 
 
    //
    // Setter Methods
    //

    void setRemoteFileDate(const QDateTime &date);

    void setRemoteFileSize(qint64 size);
 
 
 
    //
    // Methods
    //

    Q_INVOKABLE void deleteFiles() override;

    Q_INVOKABLE void startDownload() override;

    Q_INVOKABLE void startInfoDownload();

    Q_INVOKABLE void stopDownload() override;

    Q_INVOKABLE void update() override;
 
 
signals:
    void aboutToChangeFile(QString localFileName);

    void downloadProgressChanged(int percentage);

    void remoteFileDateChanged();
 
private:
    Q_DISABLE_COPY_MOVE(Downloadable_SingleFile)
 
    // Called when an error occurs during the download of the remote file, this
    // method deletes QTemporaryFile _tmpFile, emits the signal error() and
    // deletes _networkReplyDownload by calling deleteLater.  Connected to
    // &QNetworkReply::error of _networkReplyDownload.
    void downloadFileErrorReceiver(QNetworkReply::NetworkError code);
 
    // Called once download of the remote file is finished, this method
    // overwrites the local file. It deletes the QTemporaryFile _tmpFile, and
    // deletes _networkReplyDownload by calling deleteLater. Connected to
    // &QNetworkReply::finished of _networkReplyDownload.
    void downloadFileFinished();
 
    // Called during the download of the remote file, this method emits the
    // signal downloadProgress().  Connected to &QNetworkReply::downloadProgress
    // of _networkReplyDownload.
    void downloadFileProgressReceiver(qint64 bytesReceived, qint64 bytesTotal);
 
    // Called during the download of the remote file, this method reads all the
    // data that has been downloaded so far and stores it in the QTemporaryFile
    // _tmpFile.  Connected to &QNetworkReply::readyRead of
    // _networkReplyDownload.
    void downloadFilePartialDataReceiver();
 
    // Called once download of the remote file header data is finished, this
    // method updates the properties remoteFileDate and remoteFileSize, and
    // _networkReplyDownloadHeader by calling deleteLater. Connected to
    // &QNetworkReply::finished of _networkReplyDownloadHeader.
    void downloadHeaderFinished();
 
    // This member holds the download progress.
    int m_downloadProgress{0};
 
    // NetworkReply for downloading of remote file data. Set to nullptr when no
    // download is in progress.
    QPointer<QNetworkReply> m_networkReplyDownloadFile;
 
    // NetworkReply for downloading of remote file header. Set to nullptr when
    // no download is in progress.
    QPointer<QNetworkReply> m_networkReplyDownloadHeader;
 
    // Temporary file for storing partiall data when downloading the remote
    // file. Set to nullptr when no download is in progress.
    QPointer<QSaveFile> m_saveFile;
 
    // URL of the remote file, as set in the constructor
    QUrl m_url;
 
    // Name of the local file, as set in the constructor
    QString m_fileName;
 
    // Modification date of the remote file, set directly via a setter method or
    // by calling downloadRemoteFileInfo().
    QDateTime m_remoteFileDate;
 
    // Size of the remote file, set directly via a setter method or by calling
    // downloadRemoteFileInfo().
    qint64 m_remoteFileSize{-1};
};
 
} // namespace DataManagement