// Copyright (c) 2008-2009 Nokia Corporation and/or its subsidiary(-ies).

// All rights reserved.

// This component and the accompanying materials are made available

// under the terms of "Eclipse Public License v1.0"

// which accompanies this distribution, and is available

// at the URL "http://www.eclipse.org/legal/epl-v10.html".

//

// Initial Contributors:

// Nokia Corporation - initial contribution.

//

// Contributors:

//

// Description:

//

package com.symbian.smt.gui.editors.xmleditor;

import org.eclipse.core.runtime.Assert;

import org.eclipse.jface.text.BadLocationException;

import org.eclipse.jface.text.DocumentEvent;

import org.eclipse.jface.text.IDocument;

import org.eclipse.jface.text.IRegion;

import org.eclipse.jface.text.ITypedRegion;

import org.eclipse.jface.text.Region;

import org.eclipse.jface.text.TextAttribute;

import org.eclipse.jface.text.TextPresentation;

import org.eclipse.jface.text.presentation.IPresentationDamager;

import org.eclipse.jface.text.presentation.IPresentationRepairer;

import org.eclipse.swt.custom.StyleRange;

/**

 * @author barbararosi-schwartz

 * 

 */

public class NonRuleBasedDamagerRepairer implements IPresentationDamager,

		IPresentationRepairer {

	/** The document this object works on */

	protected IDocument fDocument;

	/**

	 * The default text attribute if non is returned as data by the current

	 * token

	 */

	protected TextAttribute fDefaultTextAttribute;

	/**

	 * Constructor for NonRuleBasedDamagerRepairer.

	 */

	public NonRuleBasedDamagerRepairer(TextAttribute defaultTextAttribute) {

		Assert.isNotNull(defaultTextAttribute);

		fDefaultTextAttribute = defaultTextAttribute;

	}

	/**

	 * Adds style information to the given text presentation.

	 * 

	 * @param presentation

	 *            the text presentation to be extended

	 * @param offset

	 *            the offset of the range to be styled

	 * @param length

	 *            the length of the range to be styled

	 * @param attr

	 *            the attribute describing the style of the range to be styled

	 */

	protected void addRange(TextPresentation presentation, int offset,

			int length, TextAttribute attr) {

		if (attr != null)

			presentation.addStyleRange(new StyleRange(offset, length, attr

					.getForeground(), attr.getBackground(), attr.getStyle()));

	}

	/**

	 * @see IPresentationRepairer#createPresentation(TextPresentation,

	 *      ITypedRegion)

	 */

	public void createPresentation(TextPresentation presentation,

			ITypedRegion region) {

		addRange(presentation, region.getOffset(), region.getLength(),

				fDefaultTextAttribute);

	}

	/**

	 * Returns the end offset of the line that contains the specified offset or

	 * if the offset is inside a line delimiter, the end offset of the next

	 * line.

	 * 

	 * @param offset

	 *            the offset whose line end offset must be computed

	 * @return the line end offset for the given offset

	 * @exception BadLocationException

	 *                if offset is invalid in the current document

	 */

	protected int endOfLineOf(int offset) throws BadLocationException {

		IRegion info = fDocument.getLineInformationOfOffset(offset);

		if (offset <= info.getOffset() + info.getLength())

			return info.getOffset() + info.getLength();

		int line = fDocument.getLineOfOffset(offset);

		try {

			info = fDocument.getLineInformation(line + 1);

			return info.getOffset() + info.getLength();

		} catch (BadLocationException x) {

			return fDocument.getLength();

		}

	}

	/**

	 * @see IPresentationDamager#getDamageRegion(ITypedRegion, DocumentEvent,

	 *      boolean)

	 */

	public IRegion getDamageRegion(ITypedRegion partition, DocumentEvent event,

			boolean documentPartitioningChanged) {

		if (!documentPartitioningChanged) {

			try {

				IRegion info = fDocument.getLineInformationOfOffset(event

						.getOffset());

				int start = Math.max(partition.getOffset(), info.getOffset());

				int end = event.getOffset()

						+ (event.getText() == null ? event.getLength() : event

								.getText().length());

				if (info.getOffset() <= end

						&& end <= info.getOffset() + info.getLength()) {

					// optimize the case of the same line

					end = info.getOffset() + info.getLength();

				} else

					end = endOfLineOf(end);

				end = Math.min(partition.getOffset() + partition.getLength(),

						end);

				return new Region(start, end - start);

			} catch (BadLocationException x) {

			}

		}

		return partition;

	}

	/**

	 * @see IPresentationRepairer#setDocument(IDocument)

	 */

	public void setDocument(IDocument document) {

		fDocument = document;

	}

}