#include <QtWidgets/QApplication>
#include <QtWidgets/QtWidgets>
#include <QWebEngineView>

class CenterWidget : public QWidget
{
public:
	CenterWidget(QWidget* parent = nullptr)
		: QWidget(parent) {}

	void paintEvent(QPaintEvent *event)
	{
		 QPainter painter(this);
		 painter.setPen(Qt::white);
		 QRect _rect = rect();
		 painter.fillRect(_rect, QColor(100,100,100));
		 if (auto win = parentWidget()->windowHandle())
		 {
			 QString surfaceStr("Unhandled");
			 switch (win->surfaceType())
			 {
			 case QWindow::RasterSurface:
				 surfaceStr = "Raster";
				 break;
			 case QWindow::Direct3DSurface:
				 surfaceStr = "Direct3D";
				 break;
			 case QWindow::OpenGLSurface:
				 surfaceStr = "OpenGL";
				 break;
			 }
			 painter.drawText(_rect, "Surface Type: " + surfaceStr, QTextOption(Qt::AlignCenter));
		 }
	}
};

int main(int argc, char* argv[])
{
	QApplication::setAttribute(Qt::AA_DontCreateNativeWidgetSiblings);
	QApplication app(argc, argv);
	app.setQuitOnLastWindowClosed(true);

	// Create Top Level MainWindow
	auto mainWindow = new QMainWindow();
	mainWindow->setAttribute(Qt::WA_DeleteOnClose);
	mainWindow->setWindowTitle(QString("WebView Bugs - Qt%1.%2.%3").arg(QT_VERSION_MAJOR).arg(QT_VERSION_MINOR).arg(QT_VERSION_PATCH));
	mainWindow->setCentralWidget(new CenterWidget(mainWindow));
	mainWindow->resize(800, 600);
	mainWindow->show();

	// Create WebView 1 - Initially docked in the QMainWindow -> un-dock will not render WebView anymore
	auto webView1 = new QWebEngineView();
	webView1->load(QUrl("https://qt-project.org/"));
	webView1->setAttribute(Qt::WA_NativeWindow); // For keeping raster surface on mainWindow
	
	auto dockWidget1 = new QDockWidget("WebView 1", mainWindow);
	dockWidget1->setAllowedAreas(Qt::AllDockWidgetAreas);
	mainWindow->addDockWidget(Qt::LeftDockWidgetArea, dockWidget1);
	dockWidget1->setWidget(webView1);
	
	// Create WebView 2 - Initially floating on top of the QMainWindow -> re-dock will crash on swapChain
	auto webView2 = new QWebEngineView();
	webView2->load(QUrl("https://qt-project.org/"));
	webView2->setAttribute(Qt::WA_NativeWindow); // For keeping raster surface on mainWindow

	auto dockWidget2 = new QDockWidget("WebView 2", mainWindow);
	dockWidget2->setAllowedAreas(Qt::AllDockWidgetAreas);
	mainWindow->addDockWidget(Qt::RightDockWidgetArea, dockWidget2);
	dockWidget2->setWidget(webView2);
	dockWidget2->setFloating(true);
	
	// Run Qt message loop
	return app.exec();
}