/*******************************************************************************
 * Copyright (c) 2008 IBM Corporation and others.
 * 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:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/

package org.eclipse.wst.sse.ui.internal.editor;

import java.util.ArrayList;
import java.util.List;

import org.eclipse.wst.sse.core.internal.provisional.IStructuredModel;
import org.eclipse.wst.sse.core.internal.provisional.IndexedRegion;

/**
 * This class/interface is part of an experimental API that is still under
 * development and expected to change significantly before reaching stability.
 * It is being made available at this early stage to solicit feedback from
 * pioneering adopters on the understanding that any code that uses this API
 * will almost certainly be broken (repeatedly) as the API evolves.
 */
public class SelectionConvertor {
	/**
	 * @param model
	 * @param start
	 * @param end
	 * @return the most specific mapping of this text selection to
	 *         implementors of IndexedRegion
	 */
	public Object[] getElements(IStructuredModel model, int start, int end) {
		Object[] localSelectedStructures = null;
		if (model != null) {
			IndexedRegion region = model.getIndexedRegion(start);
			if (region != null) {
				if (end <= region.getEndOffset()) {
					// single selection
					localSelectedStructures = new Object[1];
					localSelectedStructures[0] = region;
				}
				else {
					// multiple selection
					int maxLength = model.getStructuredDocument().getLength();
					List structures = new ArrayList(2);
					while (region != null && region.getEndOffset() <= end && region.getEndOffset() < maxLength) {
						structures.add(region);
						region = model.getIndexedRegion(region.getEndOffset() + 1);
					}
					localSelectedStructures = structures.toArray();
				}
			}
		}
		if (localSelectedStructures == null) {
			localSelectedStructures = new Object[0];
		}
		return localSelectedStructures;
	}
}