package at.gv.egovernment.moa.spss.api.xmlbind;

import java.io.IOException;
import java.security.cert.CertificateEncodingException;
import java.security.cert.X509Certificate;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.w3c.dom.DOMImplementation;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;

import iaik.utils.RFC2253NameParser;
import iaik.utils.RFC2253NameParserException;

import at.gv.egovernment.moa.util.Base64Utils;
import at.gv.egovernment.moa.util.Constants;

import at.gv.egovernment.moa.spss.MOAApplicationException;
import at.gv.egovernment.moa.spss.MOASystemException;

/**
 * Utility methods used by the verious <code>ResponseBuilder</code> classes.
 * 
 * @author Patrick Peck
 * @version $Id$
 */
class ResponseBuilderUtils {
  //
  // shortcuts to various XML namespace constants
  //
  private static final String MOA_NS_URI = Constants.MOA_NS_URI;
  private static final String DSIG = Constants.DSIG_PREFIX + ":";
  private static final String DSIG_NS_URI = Constants.DSIG_NS_URI;
  private static final String XMLNS_NS_URI = Constants.XMLNS_NS_URI;

  /**
   * Create a response element with all the namespaces set.
   * 
   * @param responseName The name of the response root element.
   * @return A DOM document containing the response root element and predefined
   * MOA, DSIG and XML namespace declarations.
   * @throws MOASystemException An error building the response document.
   */
  public static Document createResponse(String responseName)
    throws MOASystemException {

    try {
      DocumentBuilder docBuilder =
        DocumentBuilderFactory.newInstance().newDocumentBuilder();
      DOMImplementation impl = docBuilder.getDOMImplementation();
      Document response;
      Element root;
      String attrValue;

      response = impl.createDocument(MOA_NS_URI, responseName, null);
      root = response.getDocumentElement();

      // add namespace prefix declarations
      root.setAttributeNS(XMLNS_NS_URI, "xmlns", MOA_NS_URI);
      attrValue = "xmlns:" + Constants.DSIG_PREFIX;
      root.setAttributeNS(XMLNS_NS_URI, attrValue, DSIG_NS_URI);

      return response;
    } catch (ParserConfigurationException e) {
      throw new MOASystemException("2200", null, e);
    }
  }

  /**
   * Add a <code>SignerInfo</code> element to the response.
   * 
   * @param response The response document, in order to create new elements in
   * it.
   * @param root The root element into which the <code>SignerInfo</code> element
   * will be inserted.
   * @param cert The signer certificate to add.
   * @param isQualified Indicates, whether <code>cert</code> is a qualified
   * certificate.
   * @param isPublicAuthority Indicates, whether <code>cert</code> is
   * certificate owned by a public authority.
   * @param publicAuthorityID Information about the public authority owning
   * <code>cert</code>. Must not be <code>null</code>, if
   * <code>isPublicAuthority ! = null</code>.
   * @throws MOAApplicationException An error occurred reading data from the
   * certificate.
   */
  public static void addSignerInfo(
    Document response,
    Element root,
    X509Certificate cert,
    boolean isQualified,
    boolean isPublicAuthority,
    String publicAuthorityID)
    throws MOAApplicationException {

    Element signerInfoElem = response.createElementNS(MOA_NS_URI, "SignerInfo");
    Element x509DataElem =
      response.createElementNS(DSIG_NS_URI, DSIG + "X509Data");
    Element x509IssuerSerialElem =
      response.createElementNS(DSIG_NS_URI, DSIG + "X509IssuerSerial");
    Element x509IssuerElem =
      response.createElementNS(DSIG_NS_URI, DSIG + "X509IssuerName");
    String issuer = cert.getIssuerDN().getName();
    Element x509SerialNumberElem =
      response.createElementNS(DSIG_NS_URI, DSIG + "X509SerialNumber");
    String serialNumber = cert.getSerialNumber().toString();
    Element x509SubjectNameElem =
      response.createElementNS(DSIG_NS_URI, DSIG + "X509SubjectName");
    Element x509CertificateElem =
      response.createElementNS(DSIG_NS_URI, DSIG + "X509Certificate");
    Element qualifiedCertificateElem =
      isQualified
        ? response.createElementNS(MOA_NS_URI, "QualifiedCertificate")
        : null;
    Element publicAuthorityElem =
      isPublicAuthority
        ? response.createElementNS(MOA_NS_URI, "PublicAuthority")
        : null;
    Element codeElem =
      publicAuthorityID != null
        ? response.createElementNS(MOA_NS_URI, "Code")
        : null;

    // fill in text
    x509IssuerElem.appendChild(response.createTextNode(issuer));
    x509SerialNumberElem.appendChild(response.createTextNode(serialNumber));
    try {
      RFC2253NameParser parser = 
        new RFC2253NameParser(cert.getSubjectDN().getName());
      String subjectRfc2253 = parser.parse().getRFC2253String();
      x509SubjectNameElem.appendChild(response.createTextNode(subjectRfc2253));
    } catch (RFC2253NameParserException e) {
      x509SubjectNameElem.appendChild(
        response.createTextNode(cert.getSubjectDN().getName()));
    }
    try {
      x509CertificateElem.appendChild(
        response.createTextNode(Base64Utils.encode(cert.getEncoded())));
    } catch (CertificateEncodingException e) {
      throw new MOAApplicationException("2245", null, e);
    } catch (IOException e) {
      throw new MOAApplicationException("2245", null, e);
    }

    // build structure
    x509DataElem.appendChild(x509SubjectNameElem);
    x509IssuerSerialElem.appendChild(x509IssuerElem);
    x509IssuerSerialElem.appendChild(x509SerialNumberElem);
    x509DataElem.appendChild(x509IssuerSerialElem);
    x509DataElem.appendChild(x509CertificateElem);
    if (isQualified) {
      x509DataElem.appendChild(qualifiedCertificateElem);
    }
    if (isPublicAuthority) {
      x509DataElem.appendChild(publicAuthorityElem);
      if (publicAuthorityID != null) {
        codeElem.appendChild(response.createTextNode(publicAuthorityID));
        publicAuthorityElem.appendChild(codeElem);
      }
    }
    signerInfoElem.appendChild(x509DataElem);
    root.appendChild(signerInfoElem);
  }

  /**
   * Add an element containing <code>Code</code> and <code>Info</code>
   * subelements.
   * 
   * @param response The response document, in order to create new elements in
   * it.
   * @param root The root element into which to insert the newly created
   * element.
   * @param elementName The name of the newly created element.
   * @param code The content of the <code>Code</code> subelement.
   * @param info The content of the <code>Info</code> subelement.
   */
  public static void addCodeInfoElement(
    Document response,
    Element root,
    String elementName,
    int code,
    NodeList info) {

    Element codeInfoElem = response.createElementNS(MOA_NS_URI, elementName);
    Element codeElem = response.createElementNS(MOA_NS_URI, "Code");
    Element infoElem;
    int i;

    codeElem.appendChild(response.createTextNode(Integer.toString(code)));
    codeInfoElem.appendChild(codeElem);
    if (info != null) {
      infoElem = response.createElementNS(MOA_NS_URI, "Info");

      for (i = 0; i < info.getLength(); i++) {
        infoElem.appendChild(info.item(i).cloneNode(true));
      }
      codeInfoElem.appendChild(infoElem);
    }
    root.appendChild(codeInfoElem);
  }

}