/**********************************************
    * Copyright (C) 2010 Lukas Laag
    * This file is part of vectomatic2.
    * 
    * vectomatic2 is free software: you can redistribute it and/or modify
    * it under the terms of the GNU General Public License as published by
    * the Free Software Foundation, either version 3 of the License, or
    * (at your option) any later version.
    * 
   * vectomatic2 is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   * 
   * You should have received a copy of the GNU General Public License
   * along with vectomatic2.  If not, see http://www.gnu.org/licenses/
   **********************************************/
  package org.vectomatic.svg.edit.client.gxt;
  
  import com.extjs.gxt.ui.client.core.El;
  import com.extjs.gxt.ui.client.util.Point;
  import com.extjs.gxt.ui.client.util.Size;
  import com.extjs.gxt.ui.client.widget.Component;
  import com.extjs.gxt.ui.client.widget.Container;
  import com.extjs.gxt.ui.client.widget.Window;
  import com.extjs.gxt.ui.client.widget.layout.FitLayout;
  import com.google.gwt.core.client.GWT;
  import com.google.gwt.dom.client.Style.Position;
  import com.google.gwt.dom.client.Style.Unit;
  import com.google.gwt.user.client.ui.Widget;
  
  /**
   * GXT layout class to implement a multilayer layout based
   * on several CSS absolutely positionned divs with different
   * z-indices.
   * @author laaglu
   */
  public class AbsoluteLayerLayout extends FitLayout {
  	public static class PositionHack {
  		protected int getDy(Window window) {
  			return window.getDraggable().getDragHandle().getOffsetHeight();
  		}
  	}
  	public static class PositionHackMozilla extends PositionHack {
  		@Override
  		protected int getDy(Window window) {
  			return 0;
  		}		
  	}
  	protected void onLayout(Container<?> container, El target) {
  		super.onLayout(container, target);
  		// Retrieve the first parent with absolute layout (it
  		// ought to be the Window)
  		Widget w = container;
  		while ((w = w.getParent()) != null)  {
  			String position = w.getElement().getStyle().getPosition();
  			if (Position.ABSOLUTE.getCssName().equals(position)) {
  				break;
  			}
  		}
  		Window window = (Window)w;
  		Point p = target.getOffsetsTo(w.getElement());
  		PositionHack ph = GWT.create(PositionHack.class);
  		p.y -= ph.getDy(window);
  		GWT.log("p = " + p.toString());
  		Size windowSize = window.el().getStyleSize();
  		for (int i = 0, count = container.getItemCount(); i < count; i++) {
  			Component c = container.getItem(i);
  			Size containerSize = target.getStyleSize();
  			containerSize.width -= getSideMargins(c);
  			containerSize.height -= c.el().getMargins("tb");
  			c.getElement().getStyle().setPosition(Position.ABSOLUTE);
  			AbsoluteLayerLayoutData data = (AbsoluteLayerLayoutData) c.getData("layoutData");
  			int horizontalOffset = data.getHorizontalOffset();
  			if (data.isAttachedLeft()) {
  				c.getElement().getStyle().setLeft(p.x + horizontalOffset, Unit.PX);
  			} else {
  				c.getElement().getStyle().setRight(windowSize.width - containerSize.width - p.x + horizontalOffset, Unit.PX);
  			}
  			int verticalOffset = data.getVerticalOffset();
  			if (data.isAttachedTop()) {
  				c.getElement().getStyle().setTop(p.y + verticalOffset, Unit.PX);
  			} else {
  				c.getElement().getStyle().setBottom(windowSize.height - containerSize.height - p.y + verticalOffset, Unit.PX);
  			}
  			if (c.isRendered()) {
  				setSize(c, 
  						data.getWidth() > 0 ? data.getWidth() : containerSize.width, 
  						data.getHeight() > 0 ? data.getHeight() : containerSize.height);
  			}
  			c.getElement().getStyle().setZIndex(data.getZIndex());
  		}
  	}
  }