/**
    * This file Copyright (c) 2011-2016 Magnolia International
    * Ltd.  (http://www.magnolia-cms.com). All rights reserved.
    *
    *
    * This file is dual-licensed under both the Magnolia
    * Network Agreement and the GNU General Public License.
    * You may elect to use one or the other of these licenses.
    *
   * This file is distributed in the hope that it will be
   * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
   * implied warranty of MERCHANTABILITY or FITNESS FOR A
   * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
   * Redistribution, except as permitted by whichever of the GPL
   * or MNA you select, is prohibited.
   *
   * 1. For the GPL license (GPL), you can redistribute and/or
   * modify this file under the terms of the GNU General
   * Public License, Version 3, as published by the Free Software
   * Foundation.  You should have received a copy of the GNU
   * General Public License, Version 3 along with this program;
   * if not, write to the Free Software Foundation, Inc., 51
   * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * 2. For the Magnolia Network Agreement (MNA), this file
   * and the accompanying materials are made available under the
   * terms of the MNA which accompanies this distribution, and
   * is available at http://www.magnolia-cms.com/mna.html
   *
   * Any modifications to this file must keep this entire header
   * intact.
   *
   */
  package info.magnolia.ui.vaadin.gwt.client.widget.dnd;
  
  import info.magnolia.ui.vaadin.gwt.client.widget.PageEditorFrame;
  import info.magnolia.ui.vaadin.gwt.client.widget.controlbar.eventmanager.ControlBarEventHandler;
  import info.magnolia.ui.vaadin.gwt.client.widget.controlbar.eventmanager.ControlBarEventManager;
  
  import com.google.gwt.core.client.GWT;
  import com.google.gwt.dom.client.BodyElement;
  import com.google.gwt.dom.client.Element;
  import com.google.gwt.dom.client.NativeEvent;
  import com.google.gwt.dom.client.Style.Unit;
  import com.google.gwt.event.dom.client.HasMouseMoveHandlers;
  import com.google.gwt.event.dom.client.MouseMoveEvent;
  import com.google.gwt.event.dom.client.MouseMoveHandler;
  import com.google.gwt.event.shared.HandlerRegistration;
  import com.google.gwt.user.client.ui.Widget;
  
  /**
   * Widget used for moving {@link info.magnolia.ui.vaadin.gwt.client.widget.controlbar.ComponentBar}.
   * Wraps the moved widget and attaches {@link MouseMoveHandler} to the {@link BodyElement} of the {@link PageEditorFrame}.
   */
  public class MoveWidget extends Widget {
  
      public static final String CLASS_NAME = "mgnlEditorMoveDiv";
      public static final int OFFSET_FROM_MOUSE = 15;
  
      private FrameBodyWrapper wrapper;
  
      private PageEditorFrame frame;
  
      private ControlBarEventManager eventManager = GWT.create(ControlBarEventManager.class);
  
      public MoveWidget(Element element) {
          setElement(element);
          getElement().setId(CLASS_NAME);
      }
  
      public void attach(final PageEditorFrame frame, final int width, final int height) {
          this.frame = frame;
  
          // no other way to get the value marked !important
          String widthImp = "width: " +  width + Unit.PX.getType() + " !important;";
          String heightImp = "height: " +  height + Unit.PX.getType() + " !important;";
          getElement().setAttribute("style", widthImp + heightImp);
  
          final BodyElement frameBody = frame.getBody();
          frameBody.appendChild(this.getElement());
  
          this.wrapper = new FrameBodyWrapper(frameBody);
          wrapper.onAttach();
  
          eventManager.addMouseMoveHandler(wrapper, new ControlBarEventHandler() {
              @Override
              public void handle(NativeEvent event) {
                  int x = event.getClientX() + frame.getContentDocument().getScrollLeft();
                  int y = event.getClientY() + OFFSET_FROM_MOUSE + frame.getContentDocument().getScrollTop();
                  int maxX = frame.getBody().getOffsetWidth() - width;
                  int maxY = frame.getBody().getOffsetHeight() - height - OFFSET_FROM_MOUSE;
  
                  x = (x > maxX) ? maxX : x;
                  y = (y > maxY) ? maxY : y;
  
                  getElement().getStyle().setTop(y, Unit.PX);
                  getElement().getStyle().setLeft(x, Unit.PX);
              }
          });
         super.onAttach();
 
     }
 
     public void detach() {
         frame.getBody().removeChild(this.getElement());
         eventManager.removeMouseMoveHandler(wrapper);
         wrapper.onDetach();
         super.onDetach();
     }
 
     /**
      * Wrapper to attach {@link HasMouseMoveHandlers} to the frames body element.
      */
     class FrameBodyWrapper extends Widget implements HasMouseMoveHandlers {
 
         FrameBodyWrapper(Element frame) {
             setElement(frame);
         }
 
         @Override
         public HandlerRegistration addMouseMoveHandler(MouseMoveHandler handler) {
             return addDomHandler(handler, MouseMoveEvent.getType());
         }
 
         @Override
         protected void onAttach() {
             super.onAttach();
         }
 
         @Override
         protected void onDetach() {
             super.onDetach();
         }
     }
 
 }