/*******************************************************************************
 * Copyright (c) 2005 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
 *     
 *******************************************************************************/
package org.eclipse.wst.xml.ui.internal.catalog;

import java.util.Collection;
import java.util.HashMap;

import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IExtensionPoint;
import org.eclipse.core.runtime.IExtensionRegistry;
import org.eclipse.core.runtime.Platform;
import org.eclipse.wst.xml.ui.internal.XMLUIPlugin;

public class CatalogFileTypeRegistryReader {
	private static CatalogFileTypeRegistryReader _instance;

	static final String ATT_DESCRIPTION = "description"; //$NON-NLS-1$

	static final String ATT_EXTENSIONS = "extensions"; //$NON-NLS-1$

	static final String ATT_ICON = "icon"; //$NON-NLS-1$

	static final String ATT_ID = "id"; //$NON-NLS-1$

	static final String EXTENSION_POINT_ID = "catalogFileType"; //$NON-NLS-1$

	static final String TAG_NAME = "fileType"; //$NON-NLS-1$

	private static CatalogFileTypeRegistryReader getInstance() {
		if (_instance == null)
			_instance = new CatalogFileTypeRegistryReader();
		return _instance;
	}

	public static Collection getXMLCatalogFileTypes() {
		return getInstance().hashMap.values();
	}

	private HashMap hashMap;

	public CatalogFileTypeRegistryReader() {
		this.hashMap = new HashMap();
		readRegistry();
	}

	private void readElement(IConfigurationElement element) {
		if (element.getName().equals(TAG_NAME)) {
			String id = element.getAttribute(ATT_ID);
			if (id != null) {
				XMLCatalogFileType fileType = (XMLCatalogFileType) hashMap.get(id);
				if (fileType == null) {
					fileType = new XMLCatalogFileType();
					hashMap.put(id, fileType);
				}

				if (fileType.description == null) {
					String description = element.getAttribute(ATT_DESCRIPTION);
					fileType.description = description;
				}

				fileType.addExtensions(element.getAttribute(ATT_EXTENSIONS));
			}
		}
	}

	private void readRegistry() {
		readRegistry(EXTENSION_POINT_ID);
	}

	private void readRegistry(String extensionPointId) {
		IExtensionRegistry pluginRegistry = Platform.getExtensionRegistry();
		IExtensionPoint point = pluginRegistry.getExtensionPoint(XMLUIPlugin.ID, extensionPointId);
		if (point != null) {
			IConfigurationElement[] elements = point.getConfigurationElements();
			for (int i = 0; i < elements.length; i++) {
				readElement(elements[i]);
			}
		}
	}
}