package net.sf.provisioner.config;
   
   import java.io.IOException;
   import java.io.InputStream;
   import java.util.Iterator;
   import java.util.List;
   
   import net.sf.provisioner.utils.PathHelper;
   
  import org.apache.log4j.Logger;
  import org.jdom.Document;
  import org.jdom.Element;
  import org.jdom.input.SAXBuilder;
  
  public class NetworkElementFactory {
  
  	private static Logger logger = Logger.getLogger(NetworkElementFactory.class);
  	
  	
  	public static NetworkElement createElement(String networkElementName, String configPath) {
  		NetworkElement ne;
  		if (networkElementName.equalsIgnoreCase("ldap_ne_name")) {
  			ne = new LDAPNetworkElement();
  		} else {
  			ne = defaultElement();
  		}
  		ne.setConfigPath(configPath);
  		
  		InputStream customFileRef = null;
  		try {
  			customFileRef = PathHelper.pathToStream(networkElementName);
  		} catch (IOException ioe) {
  			// An exception is acceptable here.  We've no way of knowing
  			// if this points to a file, or if the user expects the
  			// system to guess the file name.
  		}
  
  		if (customFileRef == null) {
  			try {
  				customFileRef = PathHelper.pathToStream(configPath + networkElementName + ".xml");
  			} catch (IOException ioe) {
  				logger.fatal("Network element config. could not be read for '" + networkElementName + "'");
  				// TODO: decide if returning null is what we want to do here.
  				return null;
  			}
  		}
  		
  		if (customFileRef == null) {
  			logger.fatal("Network element config. could not be found for '" + networkElementName + "'");
  			// TODO: decide if returning null is what we want to do here.
  			return null;
  		}
  
  		return populateNetworkElement(ne, customFileRef);
  		/*if (customFileRef.exists()) {
  			// The user has specified a path to the config. file.
  			return populateNetworkElement(ne, customFileRef);
  		} else {
  			// The user wants the system to guess where the config. file is.
  			return populateNetworkElement(
  				ne, 
  				new File("config/" + networkElementName + ".xml")
  			);
  		}*/
  	}
  	
  	public static NetworkElement defaultElement() {
  		return new NetworkElement();
  	}
  	
  	private static NetworkElement populateNetworkElement(NetworkElement ne, InputStream xmlConfig) {
  		try {
  			Document d = new SAXBuilder().build(xmlConfig); 
  			List children = d.getContent();  
  			Iterator iterator = children.iterator();
  			while (iterator.hasNext()) {
  				Element child = (Element) iterator.next();
  				ne.getParameters(child);
  			}
  			return ne;
  		} catch (Exception e) {
  			logger.fatal("Error reading network element configuration file " + xmlConfig);
  			// TODO: throw something meaningful here.
  			return null;
  		}		
  	}
  }