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

import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

import org.w3c.dom.Element;
import org.w3c.dom.traversal.NodeIterator;

import at.gv.egovernment.moa.id.*;
import at.gv.egovernment.moa.id.auth.data.CreateXMLSignatureResponse;
import at.gv.egovernment.moa.id.auth.data.SAMLAttribute;
import at.gv.egovernment.moa.util.Constants;
import at.gv.egovernment.moa.util.DOMUtils;
import at.gv.egovernment.moa.util.XPathUtils;

/**
 * Parses an <code>&lt;InfoboxReadResponse&gt;</code> returned from
 * the security layer
 * 
 * @author Stefan Knirsch
 * @version $Id$
 */

public class CreateXMLSignatureResponseParser {
  //
  // XPath namespace prefix shortcuts
  //
  /** Xpath prefix for reaching SecurityLayer 1.0 Namespaces */
  private static final String SL10 = Constants.SL10_PREFIX + ":";
  /** Xpath prefix for reaching SecurityLayer 1.1 Namespaces */
  private static final String SL11 = Constants.SL11_PREFIX + ":";
  /** Xpath prefix for reaching SAML Namespaces */
  private static final String SAML = Constants.SAML_PREFIX + ":";
  /** Xpath prefix for reaching XML-DSIG Namespaces */
  private static final String DSIG = Constants.DSIG_PREFIX + ":";
  /** Xpath expression to the root element */
  private static final String ROOT = "/" + SL11 + "CreateXMLSignatureResponse/";
  /** Xpath expression to the SAML:Assertion element */
  private static final String SAML_ASSERTION_XPATH = ROOT + SAML + "Assertion";
  /** Xpath expression to the SAML:NameIdentifier element */
  private static final String SAML_SUBJECT_NAME_IDENTIFIER_XPATH = SAML_ASSERTION_XPATH + "/" + SAML + "AttributeStatement/" + SAML + "Subject/" + SAML + "NameIdentifier";
  /** Xpath expression to the AttributeStatement element */
  private static final String SAML_ATTRIBUTE_XPATH = SAML_ASSERTION_XPATH + "/" + SAML + "AttributeStatement/" + SAML + "Attribute";
  /** Xpath expression to the AttributeValue element */
  private static final String SAML_ATTRIBUTE_VALUE_XPATH = SAML + "AttributeValue";

  /** This is the root element of the XML-Document provided by the Security Layer Card */
  private Element sigResponse;

  /**
   * Constructor for CreateXMLSignatureResponseParser.
   * A DOM-representation of the incoming String will be created
   * @param xmlResponse <code>&lt;InfoboxReadResponse&gt;</code> as String
   * @throws AuthenticationException if any authentication error occurs
   * @throws ParseException if an element cannot be parsed
   */
  public CreateXMLSignatureResponseParser(String xmlResponse) throws AuthenticationException, ParseException {
    ErrorResponseParser erp = new ErrorResponseParser(xmlResponse);
    if (erp.getErrorCode() != null) {
      throw new AuthenticationException("auth.08", new Object[] { erp.getErrorCode(), erp.getErrorInfo()});
    }

    try {

      InputStream s = new ByteArrayInputStream(xmlResponse.getBytes("UTF-8"));
      sigResponse = DOMUtils.parseXmlValidating(s);
    }
    catch (Throwable t) {
      throw new ParseException("parser.01", new Object[] { t.toString()}, t);
    }
  }

  /**
   * Constructor for CreateXMLSignatureResponseParser.
   * A DOM-representation of the incoming Inputstream will be created
   * @param xmlResponse <code>&lt;InfoboxReadResponse&gt;</code> as InputStream
   * @throws AuthenticationException if any Authentication error occurs
   * @throws ParseException if an element cannot be parsed
   */
  public CreateXMLSignatureResponseParser(InputStream is) throws AuthenticationException, ParseException {

    ErrorResponseParser erp = new ErrorResponseParser(is);
    if (erp.getErrorCode() != null) {
      throw new AuthenticationException("auth.08", new Object[] { erp.getErrorCode(), erp.getErrorInfo()});
    }

    try {

      sigResponse = DOMUtils.parseXmlValidating(is);
    }
    catch (Throwable t) {
      throw new ParseException("parser.01", new Object[] { t.toString()}, t);
    }
  }

  /**
  * Constructor for CreateXMLSignatureResponseParser.
  * The incoming Element will be used for further operations
  * @param xmlResponse <code>&lt;InfoboxReadResponse&gt;</code> as InputStream
  */
  public CreateXMLSignatureResponseParser(Element xmlResponse) {
    sigResponse = xmlResponse;

  }

  /**
   * Parses the identity link from <code>&lt;InfoboxReadResponse&gt;</code>
   * @return Identity link
   * @throws ParseException
   */

  public CreateXMLSignatureResponse parseResponse() throws ParseException {
    CreateXMLSignatureResponse cResp;
    try {

      cResp = new CreateXMLSignatureResponse();
      cResp.setSamlNameIdentifier(XPathUtils.getElementValue(sigResponse, SAML_SUBJECT_NAME_IDENTIFIER_XPATH, null));
      cResp.setSamlAssertion((Element) XPathUtils.selectSingleNode(sigResponse, SAML_ASSERTION_XPATH));
      NodeIterator attrIter = XPathUtils.selectNodeIterator(sigResponse, SAML_ATTRIBUTE_XPATH);
      Element samlAttr;
      List samlAttributes = new ArrayList();
      while ((samlAttr = (Element) attrIter.nextNode()) != null) {
        String attrName = XPathUtils.getAttributeValue(samlAttr, "@AttributeName", "");
        String attrNamespace = XPathUtils.getAttributeValue(samlAttr, "@AttributeNamespace", "");
        String attrValue = XPathUtils.getElementValue(samlAttr, SAML_ATTRIBUTE_VALUE_XPATH, "");
        samlAttributes.add(new SAMLAttribute(attrName, attrNamespace, attrValue));
      }
      SAMLAttribute[] result = new SAMLAttribute[samlAttributes.size()];
      samlAttributes.toArray(result);
      cResp.setSamlAttributes(result);
    }
    catch (Throwable t) {
      throw new ParseException("parser.01", new Object[] { t.toString()}, t);
    }
    return cResp;
  }

}