#include <QAbstractListModel>
#include <QApplication>
#include <QIcon>
#include <QStyleFactory>
#include <QTableView>
#include <QTimer>
#include <QToolBar>
#include <QToolButton>
#include <QVBoxLayout>

class Model : public QAbstractListModel {
    Q_OBJECT

    int rows = 0;
    QTimer timer;

  public:
    Model(QWidget* parent = nullptr) : QAbstractListModel(parent) {
        connect(&timer, &QTimer::timeout, this, &Model::update);
        timer.start(1);
    }

    int rowCount(const QModelIndex& parent = QModelIndex()) const override {
        return parent.isValid() ? 0 : rows;
    }

    QVariant data(const QModelIndex& index, int role = Qt::DisplayRole) const override {
        if (role == Qt::DisplayRole)
            return QString::number(index.row());
        return {};
    }

    QVariant headerData(int section, Qt::Orientation orientation,
                        int role = Qt::DisplayRole) const {
        if (role == Qt::SizeHintRole) {
            return QSize(100, 18);
        }
        return QAbstractListModel::headerData(section, orientation, role);
    }

    Q_SLOT void update() {
        beginResetModel();
        rows = rand() % 100000;
        endResetModel();
        // beginInsertRows({}, 0, 99);
        // rows += 100;
        // endInsertRows();
    }
};

class MainWidget : public QWidget {
    Q_OBJECT

  public:
    explicit MainWidget() {
        auto layout = new QVBoxLayout(this);
        layout->setSpacing(0);
        layout->setContentsMargins(0, 0, 0, 0);
        auto bar = new QToolBar(this);
        layout->addWidget(bar);
        auto btn = new QToolButton(bar);
        btn->setIcon(QIcon::fromTheme("edit-undo"));
        bar->addWidget(btn);
        auto view = new QTableView(this);
        layout->addWidget(view);
        auto model = new Model(this);
        view->setModel(model);
        view->setVerticalScrollMode(QAbstractItemView::ScrollPerItem);

        setLayout(layout);
    }
};

int main(int argc, char* argv[]) {
    QApplication app(argc, argv);

    qApp->setStyle(QStyleFactory::create("Fusion"));

    MainWidget w;
    w.show();

    return app.exec();
}

#include "test.moc"