/*******************************************************************************
 * Copyright (c) 2001, 2004 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
 *     Jens Lukowski/Innoopract - initial renaming/restructuring
 *     
 *******************************************************************************/
package org.eclipse.wst.sse.ui.internal.taginfo;


import org.eclipse.jface.preference.IPreferenceStore;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IRegion;
import org.eclipse.jface.text.ITextHover;
import org.eclipse.jface.text.ITextViewer;
import org.eclipse.jface.text.ITypedRegion;

/**
 * Provides debug hover help
 * 
 * @author amywu
 * @see org.eclipse.jface.text.ITextHover
 */
public class DebugInfoHoverProcessor implements ITextHover {
	public static final String TRACEFILTER = "debuginfohover"; //$NON-NLS-1$
	protected IPreferenceStore fPreferenceStore = null;

	public DebugInfoHoverProcessor() {
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jface.text.ITextHover#getHoverInfo(org.eclipse.jface.text.ITextViewer,
	 *      org.eclipse.jface.text.IRegion)
	 */
	public String getHoverInfo(ITextViewer viewer, IRegion hoverRegion) {
		String displayText = null;
		if ((hoverRegion == null) || (viewer == null) || (viewer.getDocument() == null)) {
			displayText = null;
		} else {
			int offset = hoverRegion.getOffset();

			ITypedRegion region;
			try {
				region = viewer.getDocument().getPartition(offset);
				if (region != null) {
					displayText = region.getType();
				} else {
					displayText = "Null Region was returned?!"; //$NON-NLS-1$
				}
			} catch (BadLocationException e) {
				displayText = "BadLocationException Occurred!?"; //$NON-NLS-1$
			}

		}
		return displayText;
	}

	/**
	 * Returns the region to hover the text over based on the offset.
	 * 
	 * @param textViewer
	 * @param offset
	 * 
	 * @return IRegion region to hover over if offset is not over invalid
	 *         whitespace. otherwise, returns <code>null</code>
	 * 
	 * @see ITextHover#getHoverRegion(ITextViewer, int)
	 */
	public IRegion getHoverRegion(ITextViewer textViewer, int offset) {
		ITypedRegion region = null;
		if ((textViewer == null) || (textViewer.getDocument() == null)) {
			region = null;
		} else {

			try {
				region = textViewer.getDocument().getPartition(offset);
			} catch (BadLocationException e) {
				region = null;
			}
		}
		return region;
	}
}