/**
 * Copyright (c) 2006 Borland Software Corporation
 * 
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    bblajer - initial API and implementation
 */
package org.eclipse.gmf.runtime.lite.commands;

import org.eclipse.emf.common.command.AbstractCommand;
import org.eclipse.emf.ecore.EObject;
import org.eclipse.emf.ecore.EStructuralFeature;
import org.eclipse.gmf.runtime.notation.Edge;
import org.eclipse.gmf.runtime.notation.NotationPackage;
import org.eclipse.gmf.runtime.notation.View;

public class ReplaceNotationalElementCommand extends AbstractCommand {
	private final CreateNotationalElementCommand createCommand;
	private final RemoveNotationalElementCommand removeCommand;
	private final View obsoleteView;

	public ReplaceNotationalElementCommand(View parentView, CreateNotationalElementCommand createCommand, View obsoleteView) {
		this.createCommand = createCommand;
		this.obsoleteView = obsoleteView;
		this.removeCommand = obsoleteView instanceof Edge ? new RemoveNotationalEdgeCommand(parentView, obsoleteView) : new RemoveNotationalElementCommand(parentView, obsoleteView);
	}

	public boolean canExecute() {
		return createCommand != null && createCommand.canExecute() && removeCommand != null && removeCommand.canExecute();
	}

	public boolean canUndo() {
		return createCommand != null && createCommand.canUndo() && removeCommand != null && removeCommand.canUndo();
	}

	public void execute() {
		createCommand.execute();
		removeCommand.execute();
		View createdView = createCommand.getCreatedView();
		if (createdView != null && obsoleteView != null && createdView.eClass().equals(obsoleteView.eClass())) {
			if (NotationPackage.eINSTANCE.getNode().equals(createdView.eClass())) {
				copy(obsoleteView, createdView, NotationPackage.eINSTANCE.getNode_LayoutConstraint());
			} else if (NotationPackage.eINSTANCE.getEdge().equals(createdView.eClass())) {
				copy(obsoleteView, createdView, NotationPackage.eINSTANCE.getEdge_Bendpoints());
			}
		}
	}

	private void copy(EObject source, EObject target, EStructuralFeature feature) {
		EObject oldValue = (EObject) source.eGet(feature);
		if (oldValue == null) {
			return;	//nothing to copy
		}
		EObject newValue = (EObject) target.eGet(feature);
		if (newValue != null && !newValue.eClass().equals(oldValue.eClass())) {
			return;	//incompatible instances.
		}
		target.eSet(feature, oldValue);
	}

	public void undo() {
		View createdView = createCommand.getCreatedView();
		if (createdView != null && obsoleteView != null && createdView.eClass().equals(obsoleteView.eClass())) {
			if (NotationPackage.eINSTANCE.getNode().equals(createdView.eClass())) {
				copy(createdView, obsoleteView, NotationPackage.eINSTANCE.getNode_LayoutConstraint());
			} else if (NotationPackage.eINSTANCE.getEdge().equals(createdView.eClass())) {
				copy(createdView, obsoleteView, NotationPackage.eINSTANCE.getEdge_Bendpoints());
			}
		}
		removeCommand.undo();
		createCommand.undo();
	}

	public void redo() {
		execute();
	}
}