#include <QApplication>
#include <QLabel>
#include <QPushButton>
#include <QTimer>
#include <QtPlatformHeaders/QWindowsWindowFunctions>
#include <QVBoxLayout>
#include <QWidget>

static QString statesToString(Qt::WindowStates ws)
{
    const auto to_string = [] (Qt::WindowState ws) -> QString {
        switch (ws) {
        case Qt::WindowMinimized: return QLatin1String("Qt::WindowMinimized");
        case Qt::WindowMaximized: return QLatin1String("Qt::WindowMaximized");
        case Qt::WindowFullScreen: return QLatin1String("Qt::WindowFullScreen");
        case Qt::WindowActive: return QLatin1String("Qt::WindowActive");
        default: return QString();
        }
    };

    QStringList result;
    for (const auto flag : { Qt::WindowMinimized, Qt::WindowMaximized, Qt::WindowFullScreen, Qt::WindowActive }) {
        if (ws & flag)
            result << to_string(flag);
    }
    return result.join(QLatin1Char('|'));
}

class Window : public QWidget
{
public:
    Window()
    {
        setWindowTitle(QLatin1String("MyWidget test widget"));

        const auto label = new QLabel(this);
        const auto toggle_fullscreen_button = new QPushButton(QLatin1String("Toggle fullscreen"), this);
        const auto close_button = new QPushButton(QLatin1String("Close window"), this);

        const auto layout = new QVBoxLayout(this);
        layout->addWidget(label);
        layout->addWidget(toggle_fullscreen_button);
        layout->addWidget(close_button);

        setLayout(layout);

        const auto timer = new QTimer(this);
        timer->setInterval(100);
        timer->start();
        connect(timer, &QTimer::timeout, this, [this, label] {
            label->setText(QLatin1String("Window state: ") + statesToString(windowState()));
        });

        connect(toggle_fullscreen_button, &QPushButton::clicked, this, [this] {
            setWindowState(windowState() ^ Qt::WindowFullScreen);
        });

        connect(close_button, &QPushButton::clicked, this, &QWidget::close);
    }

    bool event(QEvent *e) override
    {
        if (e->type() == QEvent::WinIdChange) {
            if (const auto win_handle = windowHandle())
                QWindowsWindowFunctions::setHasBorderInFullScreen(win_handle, true);
        }
        return QWidget::event(e);
    }
};

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

    Window w;
    w.setWindowState(Qt::WindowFullScreen);
    w.showMinimized();

    return app.exec();
}