import java.util.IdentityHashMap;
import java.util.Map;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.input.MouseDragEvent;
import javafx.scene.input.MouseEvent;
import org.eclipse.gef.mvc.fx.gestures.HoverGesture;
import org.eclipse.gef.mvc.fx.viewer.IViewer;

public class HoverGestureWithDraggedSupport extends HoverGesture {
	private final Map<Scene, EventHandler<MouseEvent>> fullDragFilters = new IdentityHashMap<>();

	@Override
	protected void doActivate() {
		super.doActivate();

		for (IViewer viewer : getDomain().getViewers().values()) {
			Scene scene = viewer.getCanvas().getScene();
			if (!fullDragFilters.containsKey(scene)) {
				EventHandler<MouseEvent> filter = new EventHandler<MouseEvent>() {
					@Override
					public void handle(MouseEvent event) {
						scene.startFullDrag();
					}
				};
				scene.addEventFilter(MouseEvent.DRAG_DETECTED, filter);
				fullDragFilters.put(scene, filter);
			}
		}
	}

	@Override
	protected void doDeactivate() {
		for (Scene scene : fullDragFilters.keySet()) {
			scene.removeEventFilter(MouseEvent.DRAG_DETECTED, fullDragFilters.remove(scene));
		}
		super.doDeactivate();
	}

	protected boolean isHoverEvent(MouseEvent event) {
		//@formatter:off
		return event.getEventType().equals(MouseEvent.MOUSE_MOVED)
				|| event.getEventType().equals(MouseEvent.MOUSE_ENTERED_TARGET)
				|| event.getEventType().equals(MouseEvent.MOUSE_EXITED_TARGET)
				|| event.getEventType().equals(MouseDragEvent.MOUSE_DRAG_OVER);
		//@formatter:on
	}
}