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

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

 * upgrade.parseDocument();

 * 

 * @author Joel Cayne

 * @version February 29, 2008

 * @since February 29, 2008

 * 

 */

public class ConfigUpgrade {

	protected ConfigFile configFile;

	protected Document doc;

	protected Properties properties;

	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);

			properties = 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.

	 * @return The properties hash with the user entered values.

	 */

	public Properties parseDocument() {

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

		addElement(SecurityEnabled.TAG);

		addElement(UserDefinition.TAG);

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

		return properties;

	}

	/**

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

				if(id != null) {

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

					if(n != null) {

						text = n.getTextContent();

						/* The tag exists in the properties hash */ 

						if (properties.containsKey(tag)) {

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

						}

					}

				} else {

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

					text = n.getTextContent();

				}

				if(text != null) {

					properties.put(tag, text);

				}

			}

		}	

	}

	/**

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

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

	 */

	public void getPropertyFile(File filename) {

		try {

			if(filename != null) {

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

			}

		} catch (IOException e) {

			Logger.err(e.getMessage());

		}

	}

}