/*!
 *
 * Copyright (c) 2019-2020 Diality Inc. - All Rights Reserved.
 * \copyright
 *          THIS CODE MAY NOT BE COPIED OR REPRODUCED IN ANY FORM,
 *          IN PART OR IN WHOLE,
 *          WITHOUT THE EXPLICIT PERMISSION OF THE COPYRIGHT OWNER.
 *
 * \file    DriveWatcher.h
 * \date    12/31/2019
 * \author  Behrouz NematiPour
 *
 */
#pragma once

// Qt
#include <QObject>

// Project
#include "main.h"
#include "threads.h"

// Define
#define _DriveWatcher Storage::DriveWatcher::I()

// forward diclations
class tst_initializations;

namespace Storage {

/*!
 * \brief   The DriveWatcher class
 * \details This class is to watch the USB device to be mounted if plugged in
 * or to be unmounted if user through UI requests it.
 * and will notify UI (user) on mounted and removed(No USB drive exists).
 */
class DriveWatcher : public QObject
{
    Q_OBJECT

    // friends
    friend class ::tst_initializations;

    bool        _mounted    = false;
    bool        _umounted   = false;
    bool        _removed    = false;
    const char *_usbDrive   = "";
    const int   _interval   = 1000; // in ms

    QThread    *_thread     = nullptr;
    bool        _init       = false;

// Singleton
SINGLETON(DriveWatcher)

public slots:
    bool init();
    bool init(QThread &vThread);

private slots:
    void quit();

protected:
    void timerEvent(QTimerEvent *) override;

private:
    void initConnections();

    void initThread(QThread &vThread);
    void quitThread();

    bool usbSeek(QString &vDevice);

    bool driveSpaceCheck(const QString &vPath, qint64 &vTotalBytes, qint64 &vAvailableBytes);

signals:
    /*!
     * \brief   didUSBDriveMount
     * \details notifies UI when USB device is available and has been mounted.
     */
    void didUSBDriveMount ();

    /*!
     * \brief   didUSBDriveUmount
     * \details notifies USB watcher on UI(user) request for USB umount.
     */
    void didUSBDriveUmount();

    /*!
     * \brief   didUSBDriveRemove
     * \details notifies UI when USB device has been removed(not exists).
     */
    void didUSBDriveRemove();

    /*!
     * \brief didSDCardFreeSpaceChange
     * \param vReady     - Device is mounted and ready
     * \note               if device ejected manually system assumes it's still ready.
     * \param vTotal     - Returns the total volume size in bytes.
     *                     Returns -1 if QStorageInfo object is not valid
     * \param vAvailable - Returns the size (in bytes) available for the current user.
     *                     It returns the total size available if the user is the root user or a system administrator.
     *                     This size can be less than or equal to the free size returned by bytesFree() function.
     *                     Returns -1 if QStorageInfo object is not valid.
     * \param vPercent   - The percentage of availabe spcae.
     * \note  Will emitted if only one of the publishing paramter changes.
     */
    void didSDCardSpaceChange(bool vReady, qint64 vTotal, qint64 vAvailable, quint8 vPercent);

private slots:
    // ----- usb
    void usbCheck();

    bool usbMount (const QString &vDevice);
    bool usbUmount(const QString &vDevice);
    void usbRemove();
    void usbError (const QString &vDevice);

    void onUSBDriveUmount();

    // ----- sdcard
    void sdcardSpaceCheck();

};

}