package at.gv.egovernment.moa.id.auth.builder;

import java.io.IOException;
import java.text.MessageFormat;
import java.util.Iterator;
import java.util.List;

import javax.xml.transform.TransformerException;

import org.w3c.dom.Element;

import at.gv.egovernment.moa.id.ParseException;
import at.gv.egovernment.moa.id.auth.data.ExtendedSAMLAttribute;
import at.gv.egovernment.moa.logging.Logger;
import at.gv.egovernment.moa.util.DOMUtils;
import at.gv.egovernment.moa.util.StringUtils;

/**
 * Base class for building authentication the AUTHBlock and final OA data SAML assertions.
 * Encapsulates methods used by the two specific builders 
 * {@link at.gv.egovernment.moa.id.auth.builder.AuthenticationBlockAssertionBuilder AuthenticationBlockAssertionBuilder}
 * and
 * {@link at.gv.egovernment.moa.id.auth.builder.AuthenticationDataAssertionBuilder AuthenticationDataAssertionBuilder}
 * 
 * @author Harald Bratko
 */
public class AuthenticationAssertionBuilder {
  
  /** the NewLine representation in Java*/
  protected static String NL = "\n";
  
  protected static String SAML_ATTRIBUTE =
  "   <saml:Attribute AttributeName=''{0}'' AttributeNamespace=''{1}''>" + NL +
  "     <saml:AttributeValue>{2}</saml:AttributeValue>" + NL +
  "   </saml:Attribute>"+ NL;

  /**
   * Empty constructor
   */
  public AuthenticationAssertionBuilder() {
  }
  
  /**
   * Builds the SAML attributes to be appended to the AUTHBlock or to the SAML assertion 
   * delivered to the online application.
   * The method traverses through the list of given SAML attribute objects and builds an 
   * XML structure (String representation) for each of the attributes. 
   * 
   * @param extendedSAMLAttributes The SAML attributes to be appended to the AUTHBlock or  
   *                               to the SAML assertion delivered to the online application.
   * @return                       A string representation including the XML structures of
   *                               the SAML attributes.
   *                               
   * @throws ParseException        If an error occurs on serializing an SAML attribute.
   */
  protected String buildExtendedSAMLAttributes(List extendedSAMLAttributes) throws ParseException
  {
    StringBuffer sb = new StringBuffer();
    if (extendedSAMLAttributes!=null) {
      Iterator it = extendedSAMLAttributes.iterator();
      while (it.hasNext()) {
        ExtendedSAMLAttribute extendedSAMLAttribute = (ExtendedSAMLAttribute)it.next();
        Object value = extendedSAMLAttribute.getValue();
        String name = extendedSAMLAttribute.getName();
        String namespace = extendedSAMLAttribute.getNameSpace();
        if (value instanceof String) {
          sb.append(MessageFormat.format( SAML_ATTRIBUTE, new Object[] {name, namespace, value}));
        } else if (value instanceof Element) {
          try {
            String serializedValue = DOMUtils.serializeNode((Element)(value));
            serializedValue = StringUtils.removeXMLDeclaration(serializedValue);
            sb.append(MessageFormat.format( SAML_ATTRIBUTE, new Object[] {name, namespace, serializedValue}));
          } catch (TransformerException e) {
            Logger.error("Error on serializing SAML attribute \"" + name + 
              " (namespace: \"" + namespace + "\".");
            throw new ParseException("parser.05", new Object[] { name, namespace});
          } catch (IOException e) {
            Logger.error("Error on serializing SAML attribute \"" + name + 
              " (namespace: \"" + namespace + "\".");
            throw new ParseException("parser.05", new Object[] { name, namespace});
          }
        }
      }
    }
   return sb.toString();
  }

}