/*******************************************************************************
 * 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;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IExtensionRegistry;
import org.eclipse.core.runtime.Platform;
import org.eclipse.core.runtime.content.IContentType;
import org.eclipse.core.runtime.content.IContentTypeManager;
import org.eclipse.wst.sse.core.internal.format.IStructuredFormatProcessor;
import org.eclipse.wst.sse.ui.internal.extension.RegistryReader;
import org.osgi.framework.Bundle;

public class FormatProcessorsExtensionReader extends RegistryReader {
	private static FormatProcessorsExtensionReader instance;

	public synchronized static FormatProcessorsExtensionReader getInstance() {
		if (instance == null) {
			instance = new FormatProcessorsExtensionReader();

			IExtensionRegistry registry = Platform.getExtensionRegistry();
			instance.readRegistry(registry, "org.eclipse.wst.sse.core", "formatProcessors"); //$NON-NLS-1$ //$NON-NLS-2$
		}
		return instance;
	}

	private Map map = new HashMap();
//	 TODO: private field never read locally
	String processorClassName;

	public IStructuredFormatProcessor getFormatProcessor(String contentTypeId) {
		if (contentTypeId == null)
			return null;

		IStructuredFormatProcessor formatProcessor = null;
		if (map.containsKey(contentTypeId)) {
			formatProcessor = (IStructuredFormatProcessor) map.get(contentTypeId);
		} else {
			IContentTypeManager manager = Platform.getContentTypeManager();
			IContentType queryContentType = manager.getContentType(contentTypeId);
			boolean found = false;
			for (Iterator iter = map.keySet().iterator(); iter.hasNext();) {
				String elementContentTypeId = (String) iter.next();
				IContentType elementContentType = manager.getContentType(elementContentTypeId);
				if (queryContentType.isKindOf(elementContentType)) {
					formatProcessor = (IStructuredFormatProcessor) map.get(elementContentTypeId);
					map.put(contentTypeId, formatProcessor);
					found = true;
					break;
				}
			}

			if (!found)
				map.put(contentTypeId, null);
		}

		return formatProcessor;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.wst.sse.ui.internal.extension.RegistryReader#readElement(org.eclipse.core.runtime.IConfigurationElement)
	 */
	protected boolean readElement(IConfigurationElement element) {
		if (element.getName().equals("processor")) { //$NON-NLS-1$
			String contentTypeId = element.getAttribute("contentTypeId"); //$NON-NLS-1$
			String processorClassName = element.getAttribute("class"); //$NON-NLS-1$
			String pluginID = element.getDeclaringExtension().getNamespace();
			Bundle bundle = Platform.getBundle(pluginID);

			try {
				IStructuredFormatProcessor processor = (IStructuredFormatProcessor)bundle.loadClass(processorClassName).newInstance();
				map.put(contentTypeId, processor);

				return true;
			} catch (InstantiationException e) {
				e.printStackTrace();
			} catch (IllegalAccessException e) {
				e.printStackTrace();
			} catch (ClassNotFoundException e) {
				e.printStackTrace();
			}
		}

		return false;
	}
}