/**
 * Copyright (c) 2013, 2017 CEA LIST & LIFL 
 * 
 * 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:
 *   Cedric Dumoulin  Cedric.dumoulin@lifl.fr - Initial API and implementation
 *   Quentin Le Menez quentin.lemenez@cea.fr
 * 
 */
package org.eclipse.papyrus.internal.infra.gmfdiag.layers.model.util;

import org.eclipse.emf.ecore.EClass;
import org.eclipse.emf.ecore.EObject;
import org.eclipse.papyrus.internal.infra.gmfdiag.layers.model.NotFoundException;


/**
 * @author cedric dumoulin
 *
 */
public class ECoreUtils {

	/**
	 * Check if one of the ancestor is instance of the specified type.
	 * Ancestors are classes that contains this class
	 *
	 * @param child
	 *            Child for which we want to check the ancestor's type
	 * @param type
	 *            The expected type
	 * @return true if one of the ancestor is of the expected type. False otherwise.
	 */
	public static boolean isAncestorInstanceOf(EObject child, EClass type) {


		try {
			lookupAncestorOfType(child, type);
			return true;
		} catch (NotFoundException e) {
			return false;
		}

	}

	/**
	 * Lookup if one of the ancestor is instance of the specified type.
	 * Ancestors are classes that contains this class
	 *
	 * @param child
	 *            Child for which we want to check the ancestor's type
	 * @param type
	 *            The expected type
	 * @return the first ancestor of the specified type.
	 * @throws NotFoundException
	 *             If no ancestor is found.
	 */
	public static EObject lookupAncestorOfType(EObject child, EClass type) throws NotFoundException {
		if (child != null) {
			if (type.isInstance(child)) {
				return child;
			}

			int count = 0;
			for (EObject parent = child.eContainer(); parent != null; parent = parent.eContainer()) {
				if (++count > 100000) {
					return lookupAncestorOfType(child, type);
				}
				// Check if this is the correct type
				if (type.isInstance(parent)) {
					return parent;
				}
				if (parent == child) {
					throw new IllegalStateException("There is a cycle in the containment hierarchy of " + child);
				}
			}
		}
		// Nothing found
		throw new NotFoundException("No ancestor of the specified type");

	}
}