// TODO: parent the mainwindow

    QMessageBox mb(QMessageBox::Warning,

                   tr("Confirm Number of Samples"),

                   text,

                   QMessageBox::Apply | QMessageBox::Cancel,

                   this);

    auto cb = new QCheckBox("Don't show this again.");

    connect(cb, &QCheckBox::stateChanged, [this](int state)

            {

                warnNumOfSamples = (state == Qt::Unchecked);

            });

    mb.setCheckBox(cb);

    return mb.exec() == QMessageBox::Apply;

}

void PlotControlPanel::onAutoScaleChecked(bool checked)

{

    if (checked)

    {

        ui->lYmin->setEnabled(false);

        ui->lYmax->setEnabled(false);

        ui->spYmin->setEnabled(false);

        ui->spYmax->setEnabled(false);

        emit scaleChanged(true); // autoscale

    }

    else

    {

        ui->lYmin->setEnabled(true);

        ui->lYmax->setEnabled(true);

        ui->spYmin->setEnabled(true);

        ui->spYmax->setEnabled(true);

        emit scaleChanged(false, ui->spYmin->value(), ui->spYmax->value());

    }

}

void PlotControlPanel::onYScaleChanged()

{

    emit scaleChanged(false, ui->spYmin->value(), ui->spYmax->value());

}

bool PlotControlPanel::autoScale()

{

    return ui->cbAutoScale->isChecked();

}

double PlotControlPanel::yMax()

{

    return ui->spYmax->value();

}

double PlotControlPanel::yMin()

{

    return ui->spYmin->value();

}

void PlotControlPanel::onRangeSelected()

{

    Range r = ui->cbRangePresets->currentData().value<Range>();

    ui->spYmin->setValue(r.rmin);

    ui->spYmax->setValue(r.rmax);

    ui->cbAutoScale->setChecked(false);

}

void PlotControlPanel::setChannelInfoModel(ChannelInfoModel* model)

{

    ui->tvChannelInfo->setModel(model);

    // channel color selector

    connect(ui->tvChannelInfo->selectionModel(), &QItemSelectionModel::currentRowChanged,

            [this](const QModelIndex &current, const QModelIndex &previous)

            {

                // TODO: duplicate with below lambda

                QColor color(0,0,0,0); // transparent

                if (current.isValid())

                {

                    ui->colorSelector->setEnabled(true);

                    auto model = ui->tvChannelInfo->model();

                    color = model->data(current, Qt::ForegroundRole).value<QColor>();

                }

                else

                {

                    ui->colorSelector->setDisabled(true);

                }

                // temporarily block signals because `setColor` emits `colorChanged`

                bool wasBlocked = ui->colorSelector->blockSignals(true);

                ui->colorSelector->setColor(color);

                ui->colorSelector->blockSignals(wasBlocked);

            });

    connect(ui->colorSelector, &color_widgets::ColorSelector::colorChanged,

            [this](QColor color)

            {

                auto index = ui->tvChannelInfo->selectionModel()->currentIndex();

                ui->tvChannelInfo->model()->setData(index, color, Qt::ForegroundRole);

            });

    connect(model, &QAbstractItemModel::dataChanged,

            [this](const QModelIndex & topLeft, const QModelIndex & bottomRight, const QVector<int> & roles = QVector<int> ())

            {

                auto current = ui->tvChannelInfo->selectionModel()->currentIndex();

                // no current selection

                if (!current.isValid()) return;

                auto mod = ui->tvChannelInfo->model();

                QColor color = mod->data(current, Qt::ForegroundRole).value<QColor>();

                // temporarily block signals because `setColor` emits `colorChanged`

                bool wasBlocked = ui->colorSelector->blockSignals(true);

                ui->colorSelector->setColor(color);

                ui->colorSelector->blockSignals(wasBlocked);

            });

}

void PlotControlPanel::saveSettings(QSettings* settings)

{

    settings->beginGroup(SettingGroup_Plot);

    settings->setValue(SG_Plot_NumOfSamples, numOfSamples());

    settings->setValue(SG_Plot_AutoScale, autoScale());

    settings->setValue(SG_Plot_YMax, yMax());

    settings->setValue(SG_Plot_YMin, yMin());

    settings->endGroup();

}

void PlotControlPanel::loadSettings(QSettings* settings)

{

    settings->beginGroup(SettingGroup_Plot);

    ui->spNumOfSamples->setValue(

        settings->value(SG_Plot_NumOfSamples, numOfSamples()).toInt());

    ui->cbAutoScale->setChecked(

        settings->value(SG_Plot_AutoScale, autoScale()).toBool());

    ui->spYmax->setValue(settings->value(SG_Plot_YMax, yMax()).toDouble());

    ui->spYmin->setValue(settings->value(SG_Plot_YMin, yMin()).toDouble());

    settings->endGroup();

}