package org.vaadin.peter.contextmenu.client;
   
   import java.util.LinkedList;
   import java.util.List;
   
   import com.google.gwt.dom.client.Element;
   import com.google.gwt.dom.client.EventTarget;
   import com.google.gwt.dom.client.NativeEvent;
   import com.google.gwt.event.logical.shared.CloseEvent;
  import com.google.gwt.event.logical.shared.CloseHandler;
  import com.google.gwt.user.client.Window;
  import com.google.gwt.user.client.ui.FlowPanel;
  import com.google.gwt.user.client.ui.PopupPanel;
  import com.vaadin.client.ui.VOverlay;
  
  /**
   * Menu is a visible item of ContextMenu component. For every child menu new
   * instance of Menu class will be instantiated.
   * 
   * @author Peter Lehto / IT Mill Oy Ltd
   */
  class ContextMenuOverlay extends VOverlay {
  	private final FlowPanel root;
  
  	private final List<ContextMenuItemWidget> menuItems;
  
  	private final CloseHandler<PopupPanel> closeHandler = new CloseHandler<PopupPanel>() {
  
  		@Override
  		public void onClose(CloseEvent<PopupPanel> event) {
  			unfocusAll();
  		}
  	};
  
  	public ContextMenuOverlay() {
  		super(false, false, true);
  
  		addCloseHandler(closeHandler);
  		setStyleName("v-context-menu-container");
  
  		root = new FlowPanel();
  		root.setStyleName("v-context-menu");
  
  		menuItems = new LinkedList<ContextMenuItemWidget>();
  
  		add(root);
  	}
  
  	public boolean isSubmenuOpen() {
  		for (ContextMenuItemWidget item : menuItems) {
  			if (item.isSubmenuOpen()) {
  				return true;
  			}
  		}
  
  		return false;
  	}
  
  	private void focusFirstItem() {
  		if (menuItems.size() > 0) {
  			menuItems.iterator().next().setFocus(true);
  		}
  	}
  
  	public void setFocus(boolean focused) {
  		unfocusAll();
  
  		if (focused) {
  			focusFirstItem();
  		}
  	}
  
  	private void unfocusAll() {
  		for (ContextMenuItemWidget item : menuItems) {
  			item.setFocus(false);
  		}
  	}
  
  	protected void normalizeItemWidths() {
  		int widestItemWidth = getWidthOfWidestItem();
  
  		for (ContextMenuItemWidget item : menuItems) {
  			if (item.getOffsetWidth() <= widestItemWidth) {
  				item.setWidth(widestItemWidth + "px");
  			}
  		}
  	}
  
  	protected boolean eventTargetsPopup(NativeEvent event) {
  		EventTarget target = event.getEventTarget();
  		if (Element.is(target)) {
  			return getElement().isOrHasChild(Element.as(target));
  		}
  		return false;
  	}
  
  	private int getWidthOfWidestItem() {
  		int maxWidth = 0;
  
 		for (ContextMenuItemWidget item : menuItems) {
 			int itemWidth = item.getOffsetWidth() + 1;
 
 			if (itemWidth > maxWidth) {
 				maxWidth = itemWidth;
 			}
 		}
 
 		return maxWidth;
 	}
 
 	@Override
 	public void hide() {
 		unfocusAll();
 		closeSubMenus();
 		super.hide();
 	}
 
 	public List<ContextMenuItemWidget> getMenuItems() {
 		return menuItems;
 	}
 
 	/**
 	 * @return number of visible items in this menu
 	 */
 	public int getNumberOfItems() {
 		return this.menuItems.size();
 	}
 
 	public void openNextTo(ContextMenuItemWidget parentMenuItem) {
 		int left = parentMenuItem.getAbsoluteLeft()
 				+ parentMenuItem.getOffsetWidth();
 		int top = parentMenuItem.getAbsoluteTop();
 
         showAt(left, top);
 	}
 
 	public void closeSubMenus() {
 		for (ContextMenuItemWidget child : menuItems) {
 			child.hideSubMenu();
 		}
 	}
 
 	public void selectItemBefore(ContextMenuItemWidget item) {
 		int index = menuItems.indexOf(item);
 
 		index -= 1;
 
 		if (index < 0) {
 			index = menuItems.size() - 1;
 		}
 
 		ContextMenuItemWidget itemToSelect = menuItems.get(index);
 		itemToSelect.setFocus(true);
 	}
 
 	public void selectItemAfter(ContextMenuItemWidget item) {
 		int index = menuItems.indexOf(item);
 
 		index += 1;
 
 		if (index >= menuItems.size()) {
 			index = 0;
 		}
 
 		ContextMenuItemWidget itemToSelect = menuItems.get(index);
 		itemToSelect.setFocus(true);
 	}
 
 	public void addMenuItem(ContextMenuItemWidget menuItem) {
 		menuItem.setOverlay(this);
 
 		menuItems.add(menuItem);
 		root.add(menuItem);
 	}
 
 	public void clearItems() {
 		menuItems.clear();
 		root.clear();
 	}
 
     public void showAt(final int x, final int y) {
         setPopupPositionAndShow(new PopupPanel.PositionCallback() {
             @Override
             public void setPosition(int offsetWidth, int offsetHeight) {
                 int left = x + Window.getScrollLeft();
                 int top = y + Window.getScrollTop();
 
                 int exceedingWidth = (offsetWidth + left) - (Window.getClientWidth() + Window.getScrollLeft());
                 if (exceedingWidth > 0) {
                     left -= exceedingWidth;
                     if (left < 0) {
                         left = 0;
                     }
                 }
 
                 int exceedingHeight = (offsetHeight + top) - (Window.getClientHeight() + Window.getScrollTop());
                 if (exceedingHeight > 0) {
                     top -= exceedingHeight;
                     if (top < 0) {
                         top = 0;
                     }
                 }
 
                 setPopupPosition(left, top);
             }
         });
 
         normalizeItemWidths();
     }
 }