/*!
 *
 * Copyright (c) 2019-2019 Diality Inc. - All Rights Reserved.
 * \copyright                                                       \n
 *          THIS CODE MAY NOT BE COPIED OR REPRODUCED IN ANY FORM,  \n
 *          IN PART OR IN WHOLE,                                    \n
 *          WITHOUT THE EXPLICIT PERMISSION OF THE COPYRIGHT OWNER. \n
 *
 * \file    filehandler.cpp
 * \date    2019/09/30
 * \author  Behrouz NematiPour
 *
 */
#include "filehandler.h"

// Linux
#include <sys/mount.h>
#include <errno.h>
//#include <string.h>

//Qt
#include <QDebug>
#include <QFileInfo>
#include <QProcess>

// Project
#include "maintimer.h"

// namespace
using namespace Storage;

// Singleton
SINGLETON_INIT(FileHandler)

FileHandler::FileHandler(QObject *parent) : QObject(parent) { }

bool FileHandler::umounted() const
{
    return _umounted;
}

void FileHandler::umounted(bool vUmounted)
{
    _umounted = vUmounted;
}

bool FileHandler::init()
{
    initConnections();
    return true;
}

void FileHandler::quit()
{
}

void FileHandler::initConnections()
{
    connect(_MainTimer  , SIGNAL(        didTimeout()),
            this        ,   SLOT(onMainTimerTimeout()));
    //connect(&_processCopyFolder, SIGNAL(finished(int)),
    //        this               ,   SLOT(copyFolder));
}

bool FileHandler::usbSeek(QString &vDevice) {
    QString device = "";
    for (char a = 'a'; a <= 'z'; a++) {
        device = QString("/dev/sd%1%2").arg(a).arg('1');
        if (QFileInfo::exists(device)) {
            vDevice = device;
            return true; // application is deciding on the first existing drive
        }
    }
    vDevice = device;
    return false;
}

bool FileHandler::write(const QString &vFileName, const QString &vContent, bool vAppend)
{
    QFile file(vFileName);
    QIODevice::OpenMode openMode = vAppend ?
                QFile::Text | QFile::Append :
                QFile::Text | QFile::WriteOnly;
    if (! file.open(openMode)) {
        qDebug() << "ERROR :" << tr("Can't open file for write (%1)").arg(vFileName);
        return false;
    }
    QTextStream out(&file);
    out << vContent;
    out.flush();
    return true;
}

bool FileHandler::read(const QString &vFileName, QString &vContent)
{
    QFile file(vFileName);
    if (! file.open(QFile::Text | QFile::ReadOnly)) {
        qDebug() << "ERROR :" << tr("Can't open file for read (%1)").arg(vFileName);
        return false;
    }
    QTextStream in(&file);
    vContent = in.readAll();
    return true;
}

void FileHandler::doUSBDriveMount()
{
    QString device = "";
    if (usbSeek(device)) {
        if (! umounted()) {
            usbMount(device);
        } else {
            usbUmount(_usbMount); // release
            qDebug() << tr("USB drive umounted");
        }
    } else {
        usbRemove();
    }
}

bool FileHandler::doWrite(const QString &vFileName, const QString &vContent, bool vAppend)
{
    bool ok = write(vFileName, vContent, vAppend);
    if (ok) {
        emit didWrite(vFileName);
    }
    return ok;
}

bool FileHandler::doRead(const QString &vFileName)
{
    QString mContent;
    bool ok = read(vFileName, mContent);
    if (ok) {
        emit didRead(vFileName, mContent);
    }
    return ok;
}

bool FileHandler::doExportFolder(const QString &vFolder)
{
    if ( _mounted ) {
        QString cp = "cp";
        QStringList arguments;
        arguments << "-r" << vFolder << _usbMount;
        _processCopyFolder.start(cp, arguments);
        return true;
    }
    return false;
}

void FileHandler::usbError(const QString &vDevice)
{
    switch (errno) {
    case EBUSY:
        qDebug() << tr("%1 - Device or resource busy (%2)").arg(errno).arg(vDevice);
        _mounted = true;
        break;
    default:
        qDebug() << tr("%1 - %2 (%3 , %4)").arg(errno).arg(strerror(errno)).arg(vDevice).arg(_usbMount);
        break;
    }
}

bool FileHandler::usbMount(const QString &vDevice)
{
    bool ok;
    _usbDrive = vDevice.toLatin1().constData();
    ok = mount(_usbDrive, _usbMount, _usbfsys, 0, "") == 0;
    if (ok) {
        _mounted = true;
        qDebug() << tr("USB flash drive %1 has been mounted on %2").arg(vDevice).arg(_usbMount);
        emit didUSBDriveMount();
    } else {
        usbError(vDevice);
    }
    return ok;
}

bool FileHandler::usbUmount(const QString &vDevice)
{
    bool ok;
    ok = umount(vDevice.toLatin1().constData()) == 0;
    if (ok) {
        _mounted = false;
        emit didUSBDriveUmount();
    } else {
        // the error is irrelevant, commented out for now
        //usbError(vDevice);
    }
    return ok;
}

void FileHandler::usbRemove()
{
    usbUmount(_usbMount);
    umounted(false);
    emit didUSBDriveRemove();
    qDebug() << tr("USB drive removed");
}

void FileHandler::onMainTimerTimeout()
{
    doUSBDriveMount();
}