/*******************************************************************************
 * Copyright (c) 2005 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.css.ui.internal.selection;

import org.eclipse.jface.action.IAction;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.ITextSelection;
import org.eclipse.jface.text.Region;
import org.eclipse.wst.css.core.internal.provisional.document.ICSSNode;
import org.eclipse.wst.css.ui.internal.CSSUIMessages;
import org.eclipse.wst.sse.core.internal.provisional.IndexedRegion;
import org.eclipse.wst.sse.ui.internal.selection.StructuredSelectActionDelegate;

/**
 * Selects previous CSS element
 */
public class StructuredSelectPreviousCSSActionDelegate extends StructuredSelectActionDelegate {

	protected IndexedRegion getCursorIndexedRegion(IDocument document, ITextSelection textSelection) {
		IndexedRegion indexedRegion = null;

		indexedRegion = getIndexedRegion(document, textSelection.getOffset());

		return indexedRegion;
	}

	protected Region getNewSelectionRegion(IndexedRegion indexedRegion, ITextSelection textSelection) {
		Region newRegion = null;
		if (indexedRegion instanceof ICSSNode) {
			ICSSNode cursorNode = (ICSSNode) indexedRegion;

			Region cursorNodeRegion = new Region(indexedRegion.getStartOffset(), indexedRegion.getEndOffset() - indexedRegion.getStartOffset());
			int currentOffset = textSelection.getOffset();
			int currentEndOffset = currentOffset + textSelection.getLength();
			if (cursorNodeRegion.getOffset() >= currentOffset && cursorNodeRegion.getOffset() <= currentEndOffset && cursorNodeRegion.getOffset() + cursorNodeRegion.getLength() >= currentOffset && cursorNodeRegion.getOffset() + cursorNodeRegion.getLength() <= currentEndOffset) {
				ICSSNode newNode = cursorNode.getPreviousSibling();
				if (newNode == null) {
					newNode = cursorNode.getParentNode();

					if (newNode instanceof IndexedRegion) {
						IndexedRegion newIndexedRegion = (IndexedRegion) newNode;
						newRegion = new Region(newIndexedRegion.getStartOffset(), newIndexedRegion.getEndOffset() - newIndexedRegion.getStartOffset());
					}
				}
				else {
					if (newNode instanceof IndexedRegion) {
						IndexedRegion newIndexedRegion = (IndexedRegion) newNode;
						newRegion = new Region(newIndexedRegion.getStartOffset(), currentEndOffset - newIndexedRegion.getStartOffset());
					}
				}
			}
			else
				newRegion = cursorNodeRegion;
		}
		return newRegion;
	}

	public void init(IAction action) {
		if (action != null) {
			action.setText(CSSUIMessages.StructureSelectPrevious_label);
			action.setToolTipText(CSSUIMessages.StructureSelectPrevious_tooltip);
			action.setDescription(CSSUIMessages.StructureSelectPrevious_description);
		}
	}

}