/*
 * Created on 19.11.2003
 *
 * (c) Stabsstelle IKT-Strategie des Bundes
 */
package at.gv.egovernment.moa.ss.erechtclient.moainvoker;

import java.io.IOException;
import java.io.OutputStream;
import java.rmi.RemoteException;
import java.util.Vector;

import javax.xml.namespace.QName;
import javax.xml.rpc.Call;
import javax.xml.rpc.Service;
import javax.xml.rpc.ServiceException;
import javax.xml.rpc.ServiceFactory;

import org.apache.axis.message.SOAPBodyElement;
import org.apache.log4j.Logger;
import org.apache.xerces.parsers.DOMParser;
import org.apache.xerces.xni.parser.XMLInputSource;
import org.apache.xml.serialize.OutputFormat;
import org.apache.xml.serialize.XMLSerializer;
import org.w3c.dom.DOMConfiguration;
import org.w3c.dom.Document;
import org.w3c.dom.Element;

import at.gv.egovernment.moa.ss.erechtclient.ERechtClientException;
import at.gv.egovernment.moa.ss.erechtclient.init.Constants;
import at.gv.egovernment.moa.ss.erechtclient.util.DOMUtils;

/**
 * @author Gregor Karlinger (mailto:gregor.karlinger@cio.gv.at) 
 */
public class MOAInvoker
{
  private static Logger logger_ = Logger.getLogger(Constants.LH_MOAINVOKER_);

  private static final String NAME_ERROR_ = "ErrorResponse";
  private static final String NAME_ERROR_CODE_ = "ErrorCode";
  private static final String NAME_ERROR_INFO_ = "Info";

  /**
   * Invokes MOA SS.
   * 
   * @param request The XML request to be sent to MOA SS.
   * 
   * @param endpoint The endpoint of the SOAP service where to send the XML request to. 
   * 
   * @param mOASchemaLoc The schema location URI for the MOA schema (for validating the MOA SS service response).
   * 
   * @return the XML response from the service.
   * 
   * @throws Exception if getting the XML response from the SOAP response body fails.
   * 
   * @throws RemoteException if MOA SS signals an error.
   * 
   * @throws ServiceException if the SOAP client invoking MOA SS signals an error.
   */
  public static Document invokeSS(Document request, String endpoint, String mOASchemaLoc) throws ERechtClientException
  {
    QName serviceQName = new QName(Constants.MI_SS_QNAME_);
    return invoke(request, endpoint, serviceQName, mOASchemaLoc);
  }
 
  /* ---------------------------------------------------------------------------------------------------- */

  private static Document invoke(Document request, String endpoint, QName serviceQName, String mOASchemaLoc) throws ERechtClientException
  {
    Document response;
    try {
      // Instantiate AXIS service
      Service service = ServiceFactory.newInstance().createService(serviceQName);
        
      // Create and configure service call
      Call call = service.createCall();
      call.setTargetEndpointAddress(endpoint);
        
      // Create SOAP body
      SOAPBodyElement body = new SOAPBodyElement(request.getDocumentElement());
      SOAPBodyElement[] params = new SOAPBodyElement[] {body};
        
      // Make call
      Vector responses = (Vector) call.invoke(params);
        
      // Get response
      SOAPBodyElement responseBody = (SOAPBodyElement) responses.get(0);
      response = responseBody.getAsDocument();
    } 
    catch (Exception e) 
    {
      String message = "MOA SS Service invocation failed.";
      logger_.error(message, e);
      throw new ERechtClientException(message, e);
    }

    // Validate response
    DOMConfiguration docConfig = response.getDomConfig();
    DOMErrorHandler errorHandler = new DOMErrorHandler();
    docConfig.setParameter("namespaces", Boolean.FALSE);
    docConfig.setParameter("schema-location", mOASchemaLoc);
    docConfig.setParameter("schema-type", "http://www.w3.org/2001/XMLSchema");
    docConfig.setParameter("validate", Boolean.TRUE);
    docConfig.setParameter("error-handler", errorHandler);
    response.normalizeDocument();
    if (errorHandler.getErrorCount() > 0)
    {
      String message = "Parsing the MOA SS service response failed:\n" + errorHandler.getErrorSummaryMsg();
      logger_.error(message);
      throw new ERechtClientException(message);
    }
    
    // Check if first child of response root element is an error element
    Element responseElem = response.getDocumentElement();
    Element errorElem = DOMUtils.getChildElem(responseElem, Constants.NSURI_MOA_13_, NAME_ERROR_);
    if (errorElem != null)
    {
      String errorCode = DOMUtils.getChildText(errorElem, Constants.NSURI_MOA_13_, NAME_ERROR_CODE_);
      String errorInfo = DOMUtils.getChildText(errorElem, Constants.NSURI_MOA_13_, NAME_ERROR_INFO_);
      String message = "MOA SS Service indicated an error:\n" +
        "Error code: " + errorCode + "\n" +
        "Error info: " + errorInfo;
      logger_.error(message);
      throw new ERechtClientException(message);
    }
    
    return response;
  }
 
  /* ---------------------------------------------------------------------------------------------------- */

  public static void serializeElement(Element rootElem, OutputStream out) throws ERechtClientException
  {
    
    // TODO Replace with DOMImplementationLS
    OutputFormat format = new OutputFormat(rootElem.getOwnerDocument()); 

    format.setLineSeparator("\n");
    format.setIndenting(false);
    format.setPreserveSpace(true);
    format.setOmitXMLDeclaration(false);
    format.setEncoding("UTF-8");
  
    XMLSerializer serializer = new XMLSerializer(out, format);
    try 
    {
      serializer.serialize(rootElem);
    } 
    catch (Exception e) 
    {
      String message = "Serializing the XML document failed.";
      logger_.error(message);
      throw new ERechtClientException(message);    
    }
  }
}