package ie.dcu.apps.ist.actions;

import ie.dcu.apps.ist.widgets.ImageMenuManager;

import java.net.URL;
import java.util.*;

import org.eclipse.jface.action.*;
import org.eclipse.swt.events.*;
import org.eclipse.swt.widgets.*;

/**
 * Menu Manager that notifies instances of IHoverAction when they are armed and
 * disarmed.
 * 
 * @author Kevin McGuinness
 */
public class HoverMenuManager extends ImageMenuManager  {
	
	/**
	 * Stores items that have hover listeners added to them. 
	 */
	private final Set<MenuItem> hoverItems = new HashSet<MenuItem>();
	
	
	/**
	 * Create hover menu manager.
	 */
	public HoverMenuManager() {
		init();
	}

	
	/**
	 * Create hover menu manager with id and text.
	 * 
	 * @param text
	 *          the text for the menu, or <code>null</code> if none.
	 * @param imageURL
	 *          the menu image url, or <code>null</code>.
	 */
	public HoverMenuManager(String text, URL imageURL) {
		super(text, imageURL);
		init();
	}


  /**
	 * Create hover menu manager text.
	 * 
	 * @param text
	 *          the text for the menu, or <code>null</code> if none.
	 */
	public HoverMenuManager(String text) {
		super(text);
		init();
	}

	
	private void init() {
		addMenuListener(menuListener);
	}


	private void addHoverListeners() {
		Menu menu = getMenu();
		for (MenuItem item : menu.getItems()) {
			addHoverListener(item);
		}
	}
	

	private void addHoverListener(MenuItem item) {
		IHoverAction action = getHoverAction(item);
		if (action != null) {
			addHoverListener(item, action);
		}
	}

	
	private void addHoverListener(MenuItem item, IHoverAction action) {
		if (!hoverItems.contains(item)) {
			item.addArmListener(new HoverListener(action));
			hoverItems.add(item);
		}
	}
	
	
	private void disarmAll() {
		Menu menu = getMenu();
		for (MenuItem item : menu.getItems()) {
			disarm(item);
		}
	}
	
	
	private void disarm(MenuItem item) {
		IHoverAction action = getHoverAction(item);
		if (action != null) {
			disarm(action);
		}
	}


	private void disarm(IHoverAction action) {
		if (action.isArmed()) {
			action.disarm();
		}
	}
	
	
	private IHoverAction getHoverAction(MenuItem item) {
		Object data = item.getData();
		if (data instanceof ActionContributionItem) {
			IAction action = ((ActionContributionItem) data).getAction();
			
			if (action instanceof IHoverAction) {
				return (IHoverAction) action;
			}
		}
		return null;
	}


	private IMenuListener menuListener = new IMenuListener2() {
		public void menuAboutToShow(IMenuManager manager) {
			addHoverListeners();
		}

		public void menuAboutToHide(IMenuManager manager) {
			disarmAll();
		}		
	};
	
	
	private final class HoverListener implements ArmListener {
		private final IHoverAction action;

		public HoverListener(IHoverAction action) {
			this.action = action;
		}

		
		public void widgetArmed(ArmEvent e) {
			disarmAll();
			action.arm();
		}
	}
}