//------------------------------------------------------------------------------
// Copyright (c) 2005, 2006 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 implementation
//------------------------------------------------------------------------------
package org.eclipse.epf.common.utils;

import org.eclipse.core.runtime.Platform;
import org.eclipse.swt.SWT;
import org.eclipse.swt.dnd.Clipboard;
import org.eclipse.swt.dnd.Transfer;
import org.eclipse.swt.widgets.Display;
import org.osgi.framework.Bundle;

/**
 * Utility class for retrieving data from the clipboard.
 * 
 * @author Kelvin Low
 * @since 1.0
 */
public class ClipboardUtil {

	private static final String SOURCE_URL = "SourceURL:"; //$NON-NLS-1$

	private static Transfer htmlTransfer = null;

	static {
		if (SWT.getPlatform().equals("win32")) { //$NON-NLS-1$
			try {
				Bundle bundle = Platform
						.getBundle("org.eclipse.epf.common.win32.win32.x86"); //$NON-NLS-1$
				Class c = bundle
						.loadClass("org.eclipse.epf.common.win32.Win32HTMLTransfer"); //$NON-NLS-1$
				if (c != null) {
					htmlTransfer = (Transfer) c.newInstance();
				}
			} catch (Exception e) {
				htmlTransfer = null;
			}
		}
	}

	/**
	 * Gets the HTML source URL from the current clipboard.
	 * 
	 * @return the HTML source URL or <code>null</code>
	 */
	public static String getHTMLSourceURL() {
		if (htmlTransfer == null) {
			return null;
		}

		Clipboard clipboard = new Clipboard(Display.getCurrent());
		try {
			String sourceURL = null;
			String htmlContent = (String) clipboard.getContents(htmlTransfer);
			if (htmlContent != null && htmlContent.length() > 0) {
				int index = htmlContent.indexOf(SOURCE_URL);
				if (index > 0) {
					sourceURL = htmlContent.substring(index
							+ SOURCE_URL.length());
					sourceURL = sourceURL.substring(0, sourceURL
							.indexOf(FileUtil.LINE_SEP));
				}
			}
			return sourceURL;
		} finally {
			clipboard.dispose();
		}
	}

}