/*******************************************************************************
 * Copyright 2014 Federal Chancellery Austria
 * MOA-ID has been developed in a cooperation between BRZ, the Federal
 * Chancellery Austria - ICT staff unit, and Graz University of Technology.
 * 
 * Licensed under the EUPL, Version 1.1 or - as soon they will be approved by
 * the European Commission - subsequent versions of the EUPL (the "Licence");
 * You may not use this work except in compliance with the Licence.
 * You may obtain a copy of the Licence at:
 * http://www.osor.eu/eupl/
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the Licence is distributed on an "AS IS" basis,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the Licence for the specific language governing permissions and
 * limitations under the Licence.
 * 
 * This product combines work with different licenses. See the "NOTICE" text
 * file for details on the various modules and licenses.
 * The "NOTICE" text file is part of the distribution. Any derivative works
 * that you distribute must include a readable copy of the "NOTICE" text file.
 ******************************************************************************/
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.egiz.eaaf.core.impl.utils.DOMUtils;
import at.gv.egovernment.moa.id.auth.exception.ParseException;
import at.gv.egovernment.moa.id.commons.api.data.ExtendedSAMLAttribute;
import at.gv.egovernment.moa.logging.Logger;
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;
  
  protected static String SAML_ATTRIBUTE_NO_NAMESPACE =
	  "   <saml:Attribute AttributeName=''{0}''>" + NL +
	  "     <saml:AttributeValue>{1}</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<ExtendedSAMLAttribute> extendedSAMLAttributes) throws ParseException
  {
    StringBuffer sb = new StringBuffer();
    if (extendedSAMLAttributes!=null) {
      Iterator<ExtendedSAMLAttribute> 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 List<?>) {
        	if (!((List<?>)value).isEmpty()) {
        		Object firstEl = ((List<?>)value).get(0);
        		if (firstEl instanceof String) {
        			sb.append(MessageFormat.format( SAML_ATTRIBUTE, new Object[] {name, namespace, ((String)firstEl)}));
        		}
        	}
        	        	
        } 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();
  }
  
 
}