package name.abuchen.portfolio.bootstrap;

import javax.inject.Inject;
import javax.inject.Named;

import org.eclipse.e4.core.contexts.IEclipseContext;
import org.eclipse.e4.core.contexts.RunAndTrack;
import org.eclipse.e4.core.di.annotations.Execute;
import org.eclipse.e4.core.services.events.IEventBroker;
import org.eclipse.e4.ui.model.application.ui.basic.MWindow;
import org.eclipse.e4.ui.workbench.UIEvents;
import org.eclipse.e4.ui.workbench.modeling.ISaveHandler;
import org.osgi.service.event.Event;
import org.osgi.service.event.EventHandler;

// see http://www.eclipse.org/forums/index.php/t/369989/
public class SaveHandlerProcessor
{
    private final MWindow window;
    private final IEventBroker eventBroker;

    @Inject
    public SaveHandlerProcessor(@Named("name.abuchen.portfolio.ui.window.mainwindow") MWindow window, IEventBroker eventBroker)
    {
        this.window = window;
        this.eventBroker = eventBroker;
    }

    @Execute
    void installIntoContext()
    {
        eventBroker.subscribe(UIEvents.Context.TOPIC_CONTEXT, new EventHandler()
        {
            @Override
            public void handleEvent(Event event)
            {
                if (!UIEvents.isSET(event))
                    return;

                if (!window.equals(event.getProperty("ChangedElement")) || window.getContext() == null) //$NON-NLS-1$
                    return;

                window.getContext().runAndTrack(new RunAndTrack()
                {
                    private final ISaveHandler saveHandler = new CustomSaveHandler();

                    @Override
                    public boolean changed(IEclipseContext context)
                    {
                        Object value = context.get(ISaveHandler.class);

                        if (!saveHandler.equals(value))
                            context.set(ISaveHandler.class, saveHandler);

                        return true;
                    }

                });
            }

        });
    }
}