/*******************************************************************************
 * Copyright (c) 2005 Oracle Corporation.
 * 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:
 *    Ian Trimble - initial API and implementation
 *******************************************************************************/ 
package org.eclipse.jst.pagedesigner.dtmanager;

import org.eclipse.jst.jsf.core.internal.tld.CMUtil;
import org.eclipse.jst.pagedesigner.converter.ConverterFactoryRegistry;
import org.eclipse.jst.pagedesigner.converter.IConverterFactory;
import org.eclipse.jst.pagedesigner.converter.ITagConverter;
import org.eclipse.jst.pagedesigner.dtmanager.converter.internal.DTTagConverterFactory;
import org.eclipse.wst.xml.core.internal.provisional.document.IDOMDocument;
import org.w3c.dom.Element;

/**
 * DTManager is the top-level entry point for design-time (DT) services, such
 * as tag converters and design-time information.
 * 
 * <p><b>Provisional API - subject to change</b></p>
 * 
 * @author Ian Trimble - Oracle
 */
public class DTManager {

	private static DTManager instance;
	private IDTInfoFactory dtInfoFactory;

	private DTManager() {
        // no external instantiation
	}

	/**
	 * Gets the singleton DTManager instance.
	 * 
	 * @return The singleton DTManager instance.
	 */
	public static synchronized DTManager getInstance() {
		if (instance == null) {
			instance = new DTManager();
		}
		return instance;
	}

	/**
	 * Gets an ITagConverter instance for the specified Element and mode.
	 * 
	 * @param element Element instance for which to locate and return an
	 * ITagConverter instance.
	 * @param mode Mode flag (use IConverterFactory constants).
	 * @param document Target IDOMDocument instance.
	 * @return An ITagConverter instance for the specified Element and mode.
	 */
	public ITagConverter getTagConverter(Element element, int mode, IDOMDocument document) {
		ITagConverter tagConverter = null;
		String nsURI = CMUtil.getElementNamespaceURI(element);
		//try MD-driven approach
		IConverterFactory tagConverterFactory = getTagConverterFactory(nsURI);
		if (tagConverterFactory != null) {
			tagConverter = tagConverterFactory.createConverter(element, mode);
			if (tagConverter != null) {
				tagConverter.setDestDocument(document);
			} else {
				//fallback to contributed (non-MD-driven) approach
				tagConverter = ConverterFactoryRegistry.getInstance().createTagConverter(element, mode, document);
			}
		}
		return tagConverter;
	}

	/**
	 * Gets an IConverterFactory instance for the specified namespace URI.
	 * 
	 * @param nsURI Namespace URI.
	 * @return An IConverterFactory instance for the specified namespace URI.
	 */
	protected IConverterFactory getTagConverterFactory(String nsURI) {
		//TODO: future - expand to first look for registered factories
		return new DTTagConverterFactory();
	}

	/**
	 * Gets an IDTInfo instance for the specified Element.
	 * 
	 * @param element Element instance for which to locate and return IDTInfo
	 * instance.
	 * @return An IDTInfo instance for the specified Element.
	 */
	public IDTInfo getDTInfo(Element element) {
		IDTInfo dtInfo = null;
		String nsURI = CMUtil.getElementNamespaceURI(element);
		IDTInfoFactory dtInfoFactory = getDTInfoFactory(nsURI);
		if (dtInfoFactory != null) {
			dtInfo = dtInfoFactory.getDTInfo(element);
		}
		return dtInfo;
	}

	/**
	 * Gets an IDTInfoFactory instance for the specified namespace URI.
	 * 
	 * @param nsURI Namespace URI.
	 * @return An IDTInfoFactory instance for the specified namespace URI.
	 */
	protected IDTInfoFactory getDTInfoFactory(String nsURI) {
		if (dtInfoFactory == null) {
			dtInfoFactory = new DefaultDTInfoFactory();
		}
		return dtInfoFactory;
	}

}