/*
 * 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.egiz.eaaf.core.impl.idp.auth.data;

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

import org.springframework.util.Base64Utils;
import org.w3c.dom.Element;
import org.w3c.dom.traversal.NodeIterator;

import at.gv.egiz.eaaf.core.api.data.XmlNamespaceConstants;
import at.gv.egiz.eaaf.core.api.idp.auth.data.IIdentityLink;
import at.gv.egiz.eaaf.core.exceptions.EaafParserException;
import at.gv.egiz.eaaf.core.impl.utils.DomUtils;
import at.gv.egiz.eaaf.core.impl.utils.XPathUtils;

/**
 * Parses MDS from an identity link. <code>&lt;saml:Assertion&gt;</code> <br>
 * <b>This IDL parser extract NO key information!</b>
 *
 */
public class SimpleIdentityLinkAssertionParser {

  //
  // XPath namespace prefix shortcuts
  //

  /** Xpath prefix for reaching PersonData Namespaces. */
  private static final String PDATA = XmlNamespaceConstants.PD_PREFIX + ":";
  /** Xpath prefix for reaching SAML Namespaces. */
  private static final String SAML = XmlNamespaceConstants.SAML_PREFIX + ":";
  /** Xpath prefix for reaching XML-DSIG Namespaces. */
  private static final String DSIG = XmlNamespaceConstants.DSIG_PREFIX + ":";
  /** Xpath expression to the root element. */
  private static final String ROOT = "";
  /** Xpath expression to the SAMLSubjectConfirmationData element. */
  private static final String SAML_SUBJECT_CONFIRMATION_DATA_XPATH =
      ROOT + SAML + "AttributeStatement/" + SAML + "Subject/" + SAML + "SubjectConfirmation/" + SAML
          + "SubjectConfirmationData";
  /** Xpath expression to the PersonData element. */
  public static final String PERSON_XPATH =
      SAML_SUBJECT_CONFIRMATION_DATA_XPATH + "/" + PDATA + "Person";
  /** Xpath expression to the PersonData GivenName element. */
  public static final String PERSON_GIVEN_NAME_XPATH =
      PERSON_XPATH + "/" + PDATA + "Name/" + PDATA + "GivenName";
  /** Xpath expression to the PersonData FamilyName element. */
  public static final String PERSON_FAMILY_NAME_XPATH =
      PERSON_XPATH + "/" + PDATA + "Name/" + PDATA + "FamilyName";
  /** Xpath expression to the PersonData DateOfBirth element. */
  public static final String PERSON_DATE_OF_BIRTH_XPATH =
      PERSON_XPATH + "/" + PDATA + "DateOfBirth";
  /** Xpath expression to the Identification Value element. */
  public static final String PERSON_IDENT_VALUE_XPATH =
      PERSON_XPATH + "/" + PDATA + "Identification/" + PDATA + "Value";

  /** Xpath expression to the Identification Value element. */
  public static final String PERSON_IDENT_TYPE_XPATH =
      PERSON_XPATH + "/" + PDATA + "Identification/" + PDATA + "Type";

  /** Xpath expression to the DSIG X509Certificate element. */
  private static final String DSIG_CERTIFICATES_XPATH = ROOT + DSIG + "Signature/" + DSIG
      + "KeyInfo/" + DSIG + "X509Data/" + DSIG + "X509Certificate";
  /** Xpath expression to the DSIG Transforms element. */
  private static final String DSIG_REFERENCE_TRANSFORMATION_XPATH =
      ROOT + DSIG + "Signature/" + DSIG + "SignedInfo/" + DSIG + "Reference/" + DSIG + "Transforms";

  /** The IssueInstant attribute of the SAML assertion. */
  private static final String ISSUE_INSTANT_ATTR = "IssueInstant";

  public static final String ASSERTIONID = "AssertionID";

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

  /**
   * Constructor for <code>IdentityLinkAssertionParser</code>. A
   * DOM-representation of the incoming String will be created
   *
   * @param xmlAssertion <code>&lt;saml:Assertion&gt;</code> as String
   * @throws EaafParserException on any parsing error
   */
  public SimpleIdentityLinkAssertionParser(final String xmlAssertion) throws EaafParserException {
    try {
      final InputStream s = new ByteArrayInputStream(xmlAssertion.getBytes("UTF-8"));
      assertionElem = DomUtils.parseXmlValidating(s);

    } catch (final Throwable t) {
      throw new EaafParserException("parser.01", new Object[] { t.toString() }, t);

    }
  }

  /**
   * Sets the <@link assertionElem>.
   *
   * @param xmlAssertion the assertion element
   * @throws EaafParserException on any parsing error
   */
  public SimpleIdentityLinkAssertionParser(final Element xmlAssertion) throws EaafParserException {
    assertionElem = xmlAssertion;
  }

  /**
   * Constructor for <code>IdentityLinkAssertionParser</code>. A
   * DOM-representation of the incoming Inputstream will be created
   *
   * @param xmlAssertion <code>&lt;saml:Assertion&gt;</code> as InputStream
   * @throws EaafParserException on any parsing error
   */
  public SimpleIdentityLinkAssertionParser(final InputStream xmlAssertion)
      throws EaafParserException {
    try {
      assertionElem = DomUtils.parseXmlValidating(xmlAssertion);

    } catch (final Throwable t) {
      throw new EaafParserException("parser.01", new Object[] { t.toString() }, t);

    }
  }

  /**
   * Parses the identity link from the <code>&lt;saml:Assertion&gt;</code>.
   *
   * @return Identity link
   * @throws EaafParserException on any parsing error
   */

  public IIdentityLink parseIdentityLink() throws EaafParserException {
    IIdentityLink identityLink;
    try {
      identityLink = new IdentityLink();
      identityLink.setSamlAssertion(assertionElem);
      identityLink.setIssueInstant(assertionElem.getAttribute(ISSUE_INSTANT_ATTR));
      identityLink.setPrPerson((Element) XPathUtils.selectSingleNode(assertionElem, PERSON_XPATH));
      identityLink.setIdentificationValue(
          XPathUtils.getElementValue(assertionElem, PERSON_IDENT_VALUE_XPATH, ""));
      identityLink.setIdentificationType(
          XPathUtils.getElementValue(assertionElem, PERSON_IDENT_TYPE_XPATH, ""));

      final String givenname =
          XPathUtils.getElementValue(assertionElem, PERSON_GIVEN_NAME_XPATH, "");
      final String familyname =
          XPathUtils.getElementValue(assertionElem, PERSON_FAMILY_NAME_XPATH, "");

      // replace ' in name with &#39;
      // givenname = givenname.replaceAll("'", "&#39;");
      // familyname = familyname.replaceAll("'", "&#39;");

      identityLink.setGivenName(givenname);
      identityLink.setFamilyName(familyname);
      identityLink.setDateOfBirth(
          XPathUtils.getElementValue(assertionElem, PERSON_DATE_OF_BIRTH_XPATH, ""));
      final NodeIterator dsigRefTransforms =
          XPathUtils.selectNodeIterator(assertionElem, DSIG_REFERENCE_TRANSFORMATION_XPATH);
      final List transElems = new ArrayList();
      Element transformsElem;
      while ((transformsElem = (Element) dsigRefTransforms.nextNode()) != null) {
        transElems.add(transformsElem);
      }
      final Element[] result = new Element[transElems.size()];
      transElems.toArray(result);
      identityLink.setDsigReferenceTransforms(result);

      // identityLink.setPublicKey(getPublicKeys());

    } catch (final Throwable t) {
      throw new EaafParserException("parser.01", new Object[] { t.toString() }, t);
    }

    return identityLink;
  }

  /**
   * Parses a string array of decoded base64 certificates from the
   * <code>&lt;InfoboxReadResponse&gt;</code> found in the dsig-signature.
   *
   * @return String[] with raw-certificates from the dsig-signature keyinfo
   * @throws Exception In case of an error
   */
  public String[] getCertificates() throws Exception {
    final List certs = new ArrayList();
    final NodeIterator rsaIter =
        XPathUtils.selectNodeIterator(assertionElem, DSIG_CERTIFICATES_XPATH);
    Element certElem;
    while ((certElem = (Element) rsaIter.nextNode()) != null) {
      final String content = DomUtils.getText(certElem);
      certs.add(new String(Base64Utils.decodeFromString(content), "UTF-8"));

    }
    final String[] result = new String[certs.size()];
    certs.toArray(result);
    return result;

  }
}