package argon;

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.xml.messaging.*;
import javax.xml.soap.*;
import java.util.*;

/**
 * Synchronous JAXM service that returns a list of invoices for a given client.
 */
public class InvoiceInfoServlet
	extends JAXMServlet
	implements ReqRespListener
{
	MessageFactory factory = null;

	/**  
	 * Returns a list of invoices in the form of a SOAPMessage.
	 * @param message Incoming SOAPMessage containing the client's name.
	 * @return A SOAPMessage containing a list of invoices.
	 */
	public SOAPMessage onMessage(SOAPMessage message)
	{
		try
		{
			// Extract the name of the client.
			String client = extractClient(message);
					
			// Search the invoice processing system for a collection of invoices for a given client.
			Collection invoices = InvoiceProcessingSystem.getInstance().findInvoices(client);
			
			// Build and return a SOAPMessage from the collection of invoices.
			return buildMessage(invoices);
			
		}
		catch (SOAPException ex)
		{
			// Return a SOAPMessage with a SOAPFault.
			ex.printStackTrace();
			return buildFault(ex);
		}		
	}

	/**
	 * Creates an instance of a JAXM MessageFactory.
	 */
	public void init(ServletConfig config) throws ServletException
	{
		super.init(config);
		try
		{
			factory = MessageFactory.newInstance();
		}
		catch (SOAPException se)
		{
			throw new ServletException(se);
		}
	}
	
	/**
	 *  Extracts the client's name.
	 */	
	private String extractClient(SOAPMessage message) throws SOAPException
	{
		SOAPPart part = message.getSOAPPart();
		SOAPEnvelope envelope = part.getEnvelope();
		SOAPBody body = envelope.getBody();		
			
		// Extract the client's name.
		java.util.Iterator itr = body.getChildElements(envelope.createName("findInvoices"));
		if (itr.hasNext())
		{
				SOAPElement element = (SOAPElement)itr.next();
				Iterator children = element.getChildElements(envelope.createName("client")); 
				return extractData(children);			
				
		}
		return null;
	}
	
	/**
	 *  Returns a text value of a certain element.
	 */
	private String extractData(Iterator itr)
	{
		if (itr.hasNext())
		{
			SOAPElement element = (SOAPElement)itr.next();
			return element.getValue();
		}
		else
		{
			return "";
		}
	}
	
	// Builds a SOAPMessage from a collection of invoices.
	private SOAPMessage buildMessage(Collection collection) throws SOAPException
	{
		SOAPMessage message = factory.createMessage();
		SOAPPart sp = message.getSOAPPart();
		SOAPEnvelope envelope = sp.getEnvelope();
		SOAPBody bdy = envelope.getBody();

		// Add the root element "invoices" to the SOAPBody.
		SOAPBodyElement billsElement = bdy.addBodyElement(envelope.createName("invoices"));
				
		Iterator itr = collection.iterator();
		while (itr.hasNext())
		{
			Invoice bill = (Invoice)itr.next();
			
			// Add information about the bill to the root element "invoices".			
			SOAPElement billElement = billsElement.addChildElement(envelope.createName("invoice"));			
			billElement.addChildElement(envelope.createName("company")).addTextNode(bill.getCompany());			
			billElement.addChildElement(envelope.createName("client")).addTextNode(bill.getClient());
			
			String hours =	String.valueOf(bill.getHours());
			billElement.addChildElement(envelope.createName("hours")).addTextNode(hours);
			
			String rate =	String.valueOf(bill.getRate());
			billElement.addChildElement(envelope.createName("rate")).addTextNode(rate);
			
			String total =	String.valueOf(bill.getAmount());
			billElement.addChildElement(envelope.createName("total")).addTextNode(total);
		}
		
		return message;
	}
	
	// Returns SOAPMessage containing a SOAPFault.
	private SOAPMessage buildFault(Exception ex)
	{
		try
		{
			SOAPMessage message = factory.createMessage();
			SOAPPart sp = message.getSOAPPart();
			SOAPEnvelope envelope = sp.getEnvelope();
			SOAPBody bdy = envelope.getBody();
			SOAPFault fault = bdy.addFault();
			fault.setFaultString(ex.getMessage());
			return message;
		}
		catch (SOAPException se)
		{
			se.printStackTrace();
			return null;
		}		
	}
}