/**********************************************************************

 Copyright (c) 2008 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

 $Id$

 Contributors:

     IBM Rational - initial implementation

 **********************************************************************/

package org.eclipse.tptp.platform.agentcontroller.config;

import java.io.File;

import java.io.FileOutputStream;

import java.io.IOException;

import java.util.Hashtable;

import java.util.Properties;

import javax.xml.parsers.DocumentBuilderFactory;

import javax.xml.parsers.ParserConfigurationException;

import org.eclipse.tptp.platform.agentcontroller.config.Allow;

import org.eclipse.tptp.platform.agentcontroller.config.ConfigFile;

import org.eclipse.tptp.platform.agentcontroller.config.ConfigUtility;

import org.eclipse.tptp.platform.agentcontroller.config.Constants;

import org.eclipse.tptp.platform.agentcontroller.config.Logger;

import org.eclipse.tptp.platform.agentcontroller.config.SecurityEnabled;

import org.eclipse.tptp.platform.agentcontroller.config.UserDefinition;

import org.w3c.dom.Document;

import org.w3c.dom.Node;

import org.w3c.dom.NodeList;

import org.xml.sax.SAXException;

/**

 * Sample usage: <br>

 * ConfigUpgrade upgrade = new ConfigUpgrade("<AC HOME>\\config\\serviceconfig.xml"); <br>

 * upgrade.parseDocument();

 * 

 * @author jcayne

 * @version February 26, 2008

 * @since February 26, 2008

 * 

 */

public class ConfigUpgrade {

	protected ConfigFile configFile;

	protected Document doc;

	protected Properties hash;

	private static ConfigUpgrade instance = null;

	/**

	 * The method called to acquire a reference of the singleton ConfigUpgrade.

	 * @param filename The path to the serviceconfig.xml to retrieve an existing configuration from.

	 * @return An instance of ConfigUpgrade.

	 */

	public static ConfigUpgrade getInstance(String filename) {

		if(instance == null) {

			instance = new ConfigUpgrade(filename);

		}

		return instance;

	}

	/**

	 * Provides for upgrading an existing Agent Controller installation.

	 * @param filename The path to the serviceconfig.xml to retrieve an existing configuration from.

	 */

	private ConfigUpgrade(String filename) {

		try {

			doc = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(new File(filename));

			configFile = new ConfigFile(filename);

			hash = new Properties();

		} catch (SAXException e) {

			Logger.err(e.getMessage());

		} catch (IOException e) {

			Logger.err(e.getMessage());

		} catch (ParserConfigurationException e) {

			Logger.err(e.getMessage());

		}

	}

	/**

	 * Parses the serviceconfig.xml and obtains the user provided values.

	 */

	public void parseDocument() {

		hash.put(Constants.JAVA_PATH, configFile.getValue(Constants.JAVA_PATH));

		addElement(SecurityEnabled.TAG);

		addElement(UserDefinition.TAG);

		addElement(Allow.TAG, ConfigUtility.getString("Config.Allow.Host.Tag"));

	}

	/**

	 * Searches for the tag in the serviceconfig.xml and adds it to the hash.

	 * @param tag The tag to search for.

	 */

	protected void addElement(String tag) {

		addElement(tag, null);

	}

	/**

	 * Searches for the tag containing the id attribute in serviceconfig.xml and adds it to the hash.

	 * @param tag The tag to search for.

	 * @param id The id attribute to search for in the tag.

	 */

	protected void addElement(String tag, String id) {

		NodeList nl = doc.getElementsByTagName(tag);

		if(nl != null) {

			/* Traverse the nodes with the tag name adding them to the hash */

			for(int i = 0; i < nl.getLength(); i++) {

				Node n = nl.item(i);

				String text = null;

				/* Obtain the attribute value and add it to the hash */

				if(id != null) {

					n = n.getAttributes().getNamedItem(id);

					if(n != null) {

						text = n.getTextContent();

						/* The tag exists in the hash table */ 

						if (hash.containsKey(tag))

							text = (String) hash.get(tag) + "," + text;

					}

				} else {

					/* Obtain a unique tag value and add it to the hash */

					text = n.getTextContent();

				}

				if(text != null)

					hash.put(tag, text);

			}

		}	

	}

	/**

	 * Outputs the user entered values to a property file and provides a hash table containing the user entered values.

	 * @param filename The name of the property file to store the user entered values to.

	 * @return The has with the user entered values.

	 */

	public Hashtable getPropertyFile(File filename) {

		try {

			if(filename != null)

				hash.store(new FileOutputStream(filename), null);

		} catch (IOException e) {

			Logger.err(e.getMessage());

		}

		return hash;

	}

}