/**********************************************
    * Copyright (C) 2011 Lukas Laag
    * This file is part of svgreal.
    * 
    * svgreal 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.
    * 
   * svgreal 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 svgreal.  If not, see http://www.gnu.org/licenses/
   **********************************************/
  package org.vectomatic.svg.edit.client.command;
  
  import java.util.List;
  
  import org.vectomatic.dom.svg.OMSVGElement;
  import org.vectomatic.dom.svg.impl.SVGElement;
  import org.vectomatic.dom.svg.utils.SVGConstants;
  import org.vectomatic.svg.edit.client.SvgrealApp;
  import org.vectomatic.svg.edit.client.command.edit.EditManipulatorBase;
  import org.vectomatic.svg.edit.client.engine.SVGModel;
  import org.vectomatic.svg.edit.client.event.KeyPressProcessor;
  import org.vectomatic.svg.edit.client.event.MouseDownProcessor;
  import org.vectomatic.svg.edit.client.event.MouseMoveProcessor;
  import org.vectomatic.svg.edit.client.event.MouseUpProcessor;
  import org.vectomatic.svg.edit.client.event.SelectionChangedProcessor;
  import org.vectomatic.svg.edit.client.gxt.widget.CommandFactoryMenuItem;
  import org.vectomatic.svg.edit.client.model.svg.SVGElementModel;
  
  import com.extjs.gxt.ui.client.binding.FieldBinding;
  import com.extjs.gxt.ui.client.event.ComponentEvent;
  import com.extjs.gxt.ui.client.event.SelectionChangedEvent;
  import com.google.gwt.core.client.GWT;
  import com.google.gwt.dom.client.Element;
  import com.google.gwt.event.dom.client.MouseDownEvent;
  import com.google.gwt.event.dom.client.MouseMoveEvent;
  import com.google.gwt.event.dom.client.MouseUpEvent;
  
  /**
   * Base class for command factories which display a graphical
   * manipulator to let the end-user interact with an SVG element
   * @author laaglu
   */
  public abstract class ManipulatorCommandFactoryBase extends EditCommandFactoryBase implements SelectionChangedProcessor<SVGElementModel>, MouseDownProcessor, MouseMoveProcessor, MouseUpProcessor, KeyPressProcessor {
  	/**
  	 * A filter to determine if the selection represents
  	 * suitable input for this command factory
  	 */
  	protected IModelFilter filter;
  	/**
  	 * The manipulator used to interact with the SVG element
  	 */
  	protected EditManipulatorBase manipulator;
  	/**
  	 * If the command factory is invoked from the context menu,
  	 * the corresponding model
  	 */
  	protected SVGElementModel focusModel;
  	protected String state1;
  	protected String state2;
  	
  	@Override
  	public void start(Object requester) {
  		GWT.log("ManipulatorCommandFactoryBase.start(" + requester + ")");
  		super.start(requester);
  		
  		SVGModel svgModel = SvgrealApp.getApp().getActiveModel();
  		if (svgModel != null) {
  			List<SVGElementModel> elements = svgModel.getSelectionModel().getSelectedItems();
  			if (!(requester instanceof FieldBinding)) {
  				// No manipulator is required for changes through the inspector
  				showManipulator(elements);
  			}
  			
  			// If the request comes from the context menu, stop the command
  			// if the selection changes
  			if (requester instanceof CommandFactoryMenuItem && elements.size() == 1) {
  				focusModel = elements.get(0);
  			}
  		}
  	}
  
  	@Override
  	public void stop() {
  		GWT.log("ManipulatorCommandFactoryBase.stop()");
  		super.stop();
  		hideManipulator();
  		focusModel = null;
  	}
  	
  	public void showManipulator(List<SVGElementModel> models) {
  		if (filter.accept(models)) {
  			SVGElementModel model = models.get(0);
 			manipulator = getManipulator(model);
 			OMSVGElement manipulatorRep = manipulator.bind(model.getRecord());
 			Element twinGroup = model.getOwner().getTwinGroup().getElement();
 			twinGroup.appendChild(manipulatorRep.getElement());
 			updateStatus(state2);
 		}
 	}
 	
 	public void hideManipulator() {
 		if (manipulator != null) {
 			manipulator.unbind();
 			manipulator = null;
 			updateStatus(state1);
 		}
 	}
 	
 	@Override
 	public boolean processSelectionChanged(SelectionChangedEvent<SVGElementModel> se) {
 		List<SVGElementModel> models = se.getSelection();
 		GWT.log("ManipulatorCommandFactoryBase.processSelectionChanged: " + models);
 		hideManipulator();
 		if (focusModel != null && (models.size() != 1 || models.get(0) != focusModel)) {
 			stop();
 		} else {
 			showManipulator(models);
 		}
 		return true;
 	}
 	
 	@Override
 	public boolean processMouseUp(MouseUpEvent event) {
 		if (manipulator != null) {
 			return manipulator.processMouseUp(event);
 		}
 		return false;
 	}
 
 	@Override
 	public boolean processMouseMove(MouseMoveEvent event) {
 		if (manipulator != null) {
 			return manipulator.processMouseMove(event);
 		}
 		return false;
 	}
 	
 	@Override
 	public boolean processKeyPress(ComponentEvent event) {
 		if (manipulator != null) {
 			return manipulator.processKeyPress(event);
 		}
 		return false;
 	}
 
 	@Override
 	public boolean processMouseDown(MouseDownEvent event) {
 		GWT.log("ManipulatorCommandFactoryBase.processMouseDown");
 		// If the user clicks in the background or on another
 		// element, do not process the event.
 		SVGElement target = event.getNativeEvent().getEventTarget().cast();
 		if (SVGConstants.SVG_SVG_TAG.equals(target.getTagName())) {
 			return false;
 		}
 		
 		// If the user clicks on an model svg element instead
 		// of a manipulator svg element, do not process the event.
 		SVGModel svgModel = SvgrealApp.getApp().getActiveModel();
 		SVGElementModel model = svgModel.convert(target);			
 		if (model != null) {
 			return false;
 		}
 		
 		if (manipulator != null) {
 			return manipulator.processMouseDown(event);
 		}
 
 		return false;
 	}
 
 	protected abstract EditManipulatorBase getManipulator(SVGElementModel model);
 }