/*******************************************************************************
 * Copyright (c) 2000, 2003 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.ui.externaltools.internal.ant.editor.text;


import java.util.Iterator;

import org.eclipse.jface.text.IRegion;
import org.eclipse.jface.text.ITextHover;
import org.eclipse.jface.text.ITextViewer;
import org.eclipse.jface.text.Position;
import org.eclipse.jface.text.Region;
import org.eclipse.jface.text.source.Annotation;
import org.eclipse.jface.text.source.IAnnotationModel;
import org.eclipse.jface.text.source.ISourceViewer;
import org.eclipse.ui.externaltools.internal.ant.editor.derived.HTMLPrinter;


public class XMLTextHover implements ITextHover {

	/*
	 * Formats a message as HTML text.
	 */
	private String formatMessage(String message) {
		StringBuffer buffer= new StringBuffer();
		HTMLPrinter.addPageProlog(buffer);
		HTMLPrinter.addParagraph(buffer, HTMLPrinter.convertToHTMLContent(message));
		HTMLPrinter.addPageEpilog(buffer);
		return buffer.toString();
	}
	
	/*
	 * @see ITextHover#getHoverInfo(ITextViewer, IRegion)
	 */
	public String getHoverInfo(ITextViewer textViewer, IRegion hoverRegion) {
		
		if (!(textViewer instanceof ISourceViewer))
			return null;
		
		ISourceViewer sourceViewer= (ISourceViewer) textViewer;
		IAnnotationModel model= sourceViewer.getAnnotationModel();
		
		if (model != null) {
			Iterator e= new XMLAnnotationIterator(model, true);
			while (e.hasNext()) {
				Annotation a= (Annotation) e.next();
				Position p= model.getPosition(a);
				if (p.overlapsWith(hoverRegion.getOffset(), hoverRegion.getLength())) {
					String msg= ((IXMLAnnotation) a).getMessage();
					if (msg != null && msg.trim().length() > 0)
						return formatMessage(msg);
				}
			}
		}
		
		return null;
	}
	
	/*
	 * @see ITextHover#getHoverRegion(ITextViewer, int)
	 */
	public IRegion getHoverRegion(ITextViewer textViewer, int offset) {
		int startOffset= offset > 0 ? offset - 1 : offset;
		int documentLength= textViewer.getDocument() != null ? textViewer.getDocument().getLength() : 0;
		int endOffset= offset < documentLength - 1 ? offset + 1 : offset;
		return new Region(startOffset, endOffset - startOffset);
	}

}