QObject::connect(&portControl, &PortControl::portToggled,

                     this, &MainWindow::onPortToggled);

    QObject::connect(&portControl, &PortControl::skipByteRequested,

                     this, &MainWindow::skipByte);

    QObject::connect(ui->spNumOfSamples, SELECT<int>::OVERLOAD_OF(&QSpinBox::valueChanged),

                     this, &MainWindow::onNumOfSamplesChanged);

    QObject::connect(ui->cbAutoScale, &QCheckBox::toggled,

                     this, &MainWindow::onAutoScaleChecked);

    QObject::connect(ui->spYmin, SIGNAL(valueChanged(double)),

                     this, SLOT(onYScaleChanged()));

    QObject::connect(ui->spYmax, SIGNAL(valueChanged(double)),

                     this, SLOT(onYScaleChanged()));

    QObject::connect(ui->actionClear, SIGNAL(triggered(bool)),

                     this, SLOT(clearPlot()));

    // setup number of channels spinbox

    QObject::connect(ui->spNumOfChannels,

                     SELECT<int>::OVERLOAD_OF(&QSpinBox::valueChanged),

                     this, &MainWindow::onNumOfChannelsChanged);

    // setup number format buttons

    numberFormatButtons.addButton(ui->rbUint8,  NumberFormat_uint8);

    numberFormatButtons.addButton(ui->rbUint16, NumberFormat_uint16);

    numberFormatButtons.addButton(ui->rbUint32, NumberFormat_uint32);

    numberFormatButtons.addButton(ui->rbInt8,   NumberFormat_int8);

    numberFormatButtons.addButton(ui->rbInt16,  NumberFormat_int16);

    numberFormatButtons.addButton(ui->rbInt32,  NumberFormat_int32);

    numberFormatButtons.addButton(ui->rbFloat,  NumberFormat_float);

    numberFormatButtons.addButton(ui->rbASCII,  NumberFormat_ASCII);

    QObject::connect(&numberFormatButtons, SIGNAL(buttonToggled(int, bool)),

                     this, SLOT(onNumberFormatButtonToggled(int, bool)));

    // init port signals

    QObject::connect(&(this->serialPort), SIGNAL(error(QSerialPort::SerialPortError)),

                     this, SLOT(onPortError(QSerialPort::SerialPortError)));

    // set limits for axis limit boxes

    ui->spYmin->setRange((-1) * std::numeric_limits<double>::max(),

                         std::numeric_limits<double>::max());

    ui->spYmax->setRange((-1) * std::numeric_limits<double>::max(),

                         std::numeric_limits<double>::max());

    // init data arrays and plot

    numOfSamples = ui->spNumOfSamples->value();

    numOfChannels = ui->spNumOfChannels->value();

    // init channel data and curve list

    for (unsigned int i = 0; i < numOfChannels; i++)

    {

        channelBuffers.append(new FrameBuffer(numOfSamples));

        curves.append(new QwtPlotCurve());

        curves[i]->setSamples(channelBuffers[i]);

        curves[i]->setPen(makeColor(i));

        curves[i]->attach(ui->plot);

    }

    // init auto scale

    ui->plot->setAxis(ui->cbAutoScale->isChecked(),

                      ui->spYmin->value(), ui->spYmax->value());

    // init grid

    ui->plot->showGrid(ui->actionGrid->isChecked());

    ui->plot->showMinorGrid(ui->actionMinorGrid->isChecked());

    // init number format

    if (numberFormatButtons.checkedId() >= 0)

    {

        selectNumberFormat((NumberFormat) numberFormatButtons.checkedId());

    }

    else

    {

        selectNumberFormat(NumberFormat_uint8);

    }

    // Init sps (sample per second) counter

    sampleCount = 0;

    spsLabel.setText("0sps");

    spsLabel.setToolTip("samples per second (total of all channels)");

    ui->statusBar->addPermanentWidget(&spsLabel);

    spsTimer.start(SPS_UPDATE_TIMEOUT * 1000);

    QObject::connect(&spsTimer, &QTimer::timeout,

                     this, &MainWindow::spsTimerTimeout);

    // Init demo mode

    demoCount = 0;

    demoTimer.setInterval(100);

    QObject::connect(&demoTimer, &QTimer::timeout,

                     this, &MainWindow::demoTimerTimeout);

    QObject::connect(ui->actionDemoMode, &QAction::toggled,

                     this, &MainWindow::enableDemo);

    {   // init demo indicator

        QwtText demoText(" DEMO RUNNING ");  // looks better with spaces

        demoText.setColor(QColor("white"));

        demoText.setBackgroundBrush(Qt::darkRed);

        demoText.setBorderRadius(4);

        demoText.setRenderFlags(Qt::AlignLeft | Qt::AlignTop);

        demoIndicator.setText(demoText);

        demoIndicator.hide();

        demoIndicator.attach(ui->plot);

    }

}

MainWindow::~MainWindow()

{

    for (auto curve : curves)

    {

        // also deletes respective FrameBuffer

        delete curve;

    }

    if (serialPort.isOpen())

    {

        serialPort.close();

    }

    delete ui;

    ui = NULL; // we check if ui is deleted in messageHandler

}

void MainWindow::setupAboutDialog()

{

    Ui_AboutDialog uiAboutDialog;

    uiAboutDialog.setupUi(&aboutDialog);

    QObject::connect(uiAboutDialog.pbAboutQt, &QPushButton::clicked,

                     [](){ QApplication::aboutQt();});

    QString aboutText = uiAboutDialog.lbAbout->text();

    aboutText.replace("$VERSION_STRING$", VERSION_STRING);

    aboutText.replace("$VERSION_REVISION$", VERSION_REVISION);

    uiAboutDialog.lbAbout->setText(aboutText);

}

void MainWindow::onPortToggled(bool open)

{

    // make sure demo mode is disabled

    if (open && isDemoRunning()) enableDemo(false);

    ui->actionDemoMode->setEnabled(!open);

}

void MainWindow::onDataReady()

{

    if (ui->actionPause->isChecked())

    {

        serialPort.clear(QSerialPort::Input);

        return;

    }

    // a package is a set of channel data like {CHAN0_SAMPLE, CHAN1_SAMPLE...}

    int packageSize = sampleSize * numOfChannels;

    int bytesAvailable = serialPort.bytesAvailable();

    if (bytesAvailable > 0 && skipByteRequested)

    {

        serialPort.read(1);

        skipByteRequested = false;

        bytesAvailable--;

    }

    if (bytesAvailable < packageSize) return;

    int numOfPackagesToRead =

        (bytesAvailable - (bytesAvailable % packageSize)) / packageSize;

    double* channelSamples = new double[numOfPackagesToRead*numOfChannels];

    int i = 0;

    while(i < numOfPackagesToRead)

    {

        for (unsigned int ci = 0; ci < numOfChannels; ci++)

        {

            // channelSamples[ci].replace(i, (this->*readSample)());

            channelSamples[ci*numOfPackagesToRead+i] = (this->*readSample)();

        }

        i++;

    }

    for (unsigned int ci = 0; ci < numOfChannels; ci++)

    {

        addChannelData(ci,

                       channelSamples + ci*numOfPackagesToRead,

                       numOfPackagesToRead);

    }

    delete channelSamples;

}

void MainWindow::onDataReadyASCII()

{

    while(serialPort.canReadLine())

    {

        QByteArray line = serialPort.readLine();

        // discard data if paused

        if (ui->actionPause->isChecked())

        {

            return;

        }

        line = line.trimmed();

        auto separatedValues = line.split(',');

        int numReadChannels; // effective number of channels to read

        if (separatedValues.length() >= int(numOfChannels))

        {

            numReadChannels = numOfChannels;

        }

        else // there is missing channel data

        {

            numReadChannels = separatedValues.length();

            qWarning() << "Incoming data is missing data for some channels!";

        }

        // parse read line

        for (int ci = 0; ci < numReadChannels; ci++)

        {

            bool ok;

            double channelSample = separatedValues[ci].toDouble(&ok);

            if (ok)

            {

                addChannelData(ci, &channelSample, 1);

            }

            else

            {

                qWarning() << "Data parsing error for channel: " << ci;

            }

        }

    }

}

void MainWindow::onPortError(QSerialPort::SerialPortError error)

{

    switch(error)

    {

        case QSerialPort::NoError :

            break;

        case QSerialPort::ResourceError :

            qWarning() << "Port error: resource unavaliable; most likely device removed.";

            if (serialPort.isOpen())

            {

                qWarning() << "Closing port on resource error: " << serialPort.portName();

                portControl.togglePort();

            }

            portControl.loadPortList();

            break;

        case QSerialPort::DeviceNotFoundError:

            qCritical() << "Device doesn't exists: " << serialPort.portName();

            break;

        case QSerialPort::PermissionError:

            qCritical() << "Permission denied. Either you don't have \

required privileges or device is already opened by another process.";

            break;

        case QSerialPort::OpenError:

            qWarning() << "Device is already opened!";

            break;

        case QSerialPort::NotOpenError:

            qCritical() << "Device is not open!";

            break;

        case QSerialPort::ParityError:

            qCritical() << "Parity error detected.";

            break;

        case QSerialPort::FramingError:

            qCritical() << "Framing error detected.";

            break;

        case QSerialPort::BreakConditionError:

            qCritical() << "Break condition is detected.";

            break;

        case QSerialPort::WriteError:

            qCritical() << "An error occurred while writing data.";

            break;

        case QSerialPort::ReadError:

            qCritical() << "An error occurred while reading data.";

            break;

        case QSerialPort::UnsupportedOperationError:

            qCritical() << "Operation is not supported.";

            break;

        case QSerialPort::TimeoutError:

            qCritical() << "A timeout error occurred.";

            break;

        case QSerialPort::UnknownError:

            qCritical() << "Unknown error!";

            break;

        default:

            qCritical() << "Unhandled port error: " << error;

            break;

    }

}

void MainWindow::skipByte()

{

    skipByteRequested = true;

}

void MainWindow::addChannelData(unsigned int channel, double* data, unsigned size)

{

    channelBuffers[channel]->addSamples(data, size);

    sampleCount += size;

}

void MainWindow::clearPlot()

{

    for (unsigned int ci = 0; ci < numOfChannels; ci++)

    {

        channelBuffers[ci]->clear();

    }

    ui->plot->replot();

}

void MainWindow::onNumOfSamplesChanged(int value)

{

    numOfSamples = value;

    for (unsigned int ci = 0; ci < numOfChannels; ci++)

    {

        channelBuffers[ci]->resize(numOfSamples);

    }

    ui->plot->replot();

}

void MainWindow::onNumOfChannelsChanged(int value)

{

    unsigned int oldNum = this->numOfChannels;

    this->numOfChannels = value;

    if (numOfChannels > oldNum)

    {

        // add new channels

        for (unsigned int i = 0; i < numOfChannels - oldNum; i++)

        {

            channelBuffers.append(new FrameBuffer(numOfSamples));

            curves.append(new QwtPlotCurve());

            curves.last()->setSamples(channelBuffers.last());

            curves.last()->setPen(makeColor(curves.length()-1));

            curves.last()->attach(ui->plot);

        }

    }

    else if(numOfChannels < oldNum)

    {

        // remove channels

        for (unsigned int i = 0; i < oldNum - numOfChannels; i++)

        {

            // also deletes owned FrameBuffer

            delete curves.takeLast();

            channelBuffers.removeLast();

        }

    }

}

void MainWindow::onAutoScaleChecked(bool checked)

{

    if (checked)

    {

        ui->plot->setAxis(true);

        ui->lYmin->setEnabled(false);

        ui->lYmax->setEnabled(false);

        ui->spYmin->setEnabled(false);

        ui->spYmax->setEnabled(false);

    }

    else

    {

        ui->lYmin->setEnabled(true);

        ui->lYmax->setEnabled(true);

        ui->spYmin->setEnabled(true);

        ui->spYmax->setEnabled(true);

        ui->plot->setAxis(false,  ui->spYmin->value(), ui->spYmax->value());

    }

}

void MainWindow::onYScaleChanged()

{

    ui->plot->setAxis(false,  ui->spYmin->value(), ui->spYmax->value());

}

void MainWindow::onNumberFormatButtonToggled(int numberFormatId, bool checked)

{

    if (checked) selectNumberFormat((NumberFormat) numberFormatId);

}

void MainWindow::selectNumberFormat(NumberFormat numberFormatId)

{

    numberFormat = numberFormatId;

    switch(numberFormat)

    {

        case NumberFormat_uint8:

            sampleSize = 1;

            readSample = &MainWindow::readSampleAs<quint8>;

            break;

        case NumberFormat_int8:

            sampleSize = 1;

            readSample = &MainWindow::readSampleAs<qint8>;

            break;

        case NumberFormat_uint16:

            sampleSize = 2;

            readSample = &MainWindow::readSampleAs<quint16>;

            break;

        case NumberFormat_int16:

            sampleSize = 2;

            readSample = &MainWindow::readSampleAs<qint16>;

            break;

        case NumberFormat_uint32:

            sampleSize = 4;

            readSample = &MainWindow::readSampleAs<quint32>;

            break;

        case NumberFormat_int32:

            sampleSize = 4;

            readSample = &MainWindow::readSampleAs<qint32>;

            break;

        case NumberFormat_float:

            sampleSize = 4;

            readSample = &MainWindow::readSampleAs<float>;

            break;

        case NumberFormat_ASCII:

            sampleSize = 0;    // these two members should not be used

            readSample = NULL; // in this mode

            break;

    }

    if (numberFormat == NumberFormat_ASCII)

    {

        QObject::disconnect(&(this->serialPort), &QSerialPort::readyRead, 0, 0);

        QObject::connect(&(this->serialPort), &QSerialPort::readyRead,

                         this, &MainWindow::onDataReadyASCII);

        portControl.enableSkipByte();

    }

    else

    {

        QObject::disconnect(&(this->serialPort), &QSerialPort::readyRead, 0, 0);

        QObject::connect(&(this->serialPort), &QSerialPort::readyRead,

                         this, &MainWindow::onDataReady);

        portControl.enableSkipByte(false);

    }

}

template<typename T> double MainWindow::readSampleAs()

{

    T data;

    this->serialPort.read((char*) &data, sizeof(data));

    if (ui->rbLittleE->isChecked())

    {

        data = qFromLittleEndian(data);

    }

    else

    {

        data = qFromBigEndian(data);

    }

    return double(data);

}

bool MainWindow::isDemoRunning()

{

    return ui->actionDemoMode->isChecked();

}

void MainWindow::spsTimerTimeout()

{

    spsLabel.setText(QString::number(sampleCount/SPS_UPDATE_TIMEOUT) + "sps");

    sampleCount = 0;

}

void MainWindow::demoTimerTimeout()

{

    const double period = 100;

    demoCount++;

    if (demoCount > 100) demoCount = 0;

    if (!ui->actionPause->isChecked())

    {

        for (unsigned int ci = 0; ci < numOfChannels; ci++)

        {

            // we are calculating the fourier components of square wave

            double value = 4*sin(2*M_PI*double((ci+1)*demoCount)/period)/((2*(ci+1))*M_PI);

            addChannelData(ci, &value, 1);

        }

    }

}

void MainWindow::enableDemo(bool enabled)

{

    if (enabled)

    {

        if (!serialPort.isOpen())

        {

            demoTimer.start();

            ui->actionDemoMode->setChecked(true);

            demoIndicator.show();

            ui->plot->replot();

        }

        else

        {

            ui->actionDemoMode->setChecked(false);

        }

    }

    else

    {

        demoTimer.stop();

        ui->actionDemoMode->setChecked(false);

        demoIndicator.hide();

        ui->plot->replot();

    }

}

/*

  Below crude drawing demostrates how color selection occurs for

  given channel index

  0°                     <--Hue Value-->                           360°

  |* . o . + . o . * . o . + . o . * . o . + . o . * . o . + . o . |

  * -> 0-3

  + -> 4-7

  o -> 8-15

  . -> 16-31

 */

QColor MainWindow::makeColor(unsigned int channelIndex)

{

    auto i = channelIndex;

    if (i < 4)

    {

        return QColor::fromHsv(360*i/4, 255, 230);

    }

    else

    {

        double p = floor(log2(i));

        double n = pow(2, p);

        i = i - n;

        return QColor::fromHsv(360*i/n + 360/pow(2,p+1), 255, 230);

    }

}

void MainWindow::onExportCsv()

{

    bool wasPaused = ui->actionPause->isChecked();

    ui->actionPause->setChecked(true); // pause plotting

    QString fileName = QFileDialog::getSaveFileName(this, tr("Export CSV File"));

    if (fileName.isNull())  // user canceled export

    {

        ui->actionPause->setChecked(wasPaused);

    }

    else

    {

        QFile file(fileName);

        if (file.open(QIODevice::WriteOnly | QIODevice::Text))

        {

            QTextStream fileStream(&file);

            for (unsigned int ci = 0; ci < numOfChannels; ci++)

            {

                fileStream << "Channel " << ci;

                if (ci != numOfChannels-1) fileStream << ",";

            }

            fileStream << '\n';

            for (unsigned int i = 0; i < numOfSamples; i++)

            {

                for (unsigned int ci = 0; ci < numOfChannels; ci++)

                {

                    fileStream << channelBuffers[ci]->sample(i).y();

                    if (ci != numOfChannels-1) fileStream << ",";

                }

                fileStream << '\n';

            }

        }

        else

        {

            qCritical() << "File open error during export: " << file.error();

        }

    }

}

void MainWindow::messageHandler(QtMsgType type,

                                const QMessageLogContext &context,

                                const QString &msg)

{

    QString logString;

    switch (type)

    {

        case QtDebugMsg:

            logString = "[Debug] " + msg;

            break;

        case QtWarningMsg:

            logString = "[Warning] " + msg;

            break;

        case QtCriticalMsg:

            logString = "[Error] " + msg;

            break;

        case QtFatalMsg:

            logString = "[Fatal] " + msg;

            break;

    }

    if (ui != NULL) ui->ptLog->appendPlainText(logString);

    std::cerr << logString.toStdString() << std::endl;

    if (type != QtDebugMsg && ui != NULL)

    {

        ui->statusBar->showMessage(msg, 5000);

    }

}