/*
 * Copyright 2003 Federal Chancellery Austria
 * MOA-SPSS 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.spss.server.xmlbind;

import java.io.IOException;

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

import at.gv.egovernment.moa.spss.MOAApplicationException;
import at.gv.egovernment.moaspss.util.Base64Utils;
import at.gv.egovernment.moaspss.util.Constants;
import at.gv.egovernment.moaspss.util.DOMUtils;
import at.gv.egovernment.moaspss.util.XPathUtils;

/**
 * A parser to parse <code>CreateCMSSignatureRequest</code> DOM trees into
 * <code>CreateCMSSignatureRequest</code> API objects.
 *
 * @author Patrick Peck
 * @version $Id$
 */
public class CreatePDFSignatureRequestParser {

  //
  // XPath expresssions to select elements in the CreateCMSSignatureRequest
  //
  private static final String MOA = Constants.MOA_PREFIX + ":";
  private static final String KEY_IDENTIFIER_XPATH = "/" + MOA + "CreatePDFSignatureRequest/" + MOA
      + "KeyIdentifier";
  private static final String SINGLE_SIGNATURE_INFO_XPATH = "/" + MOA + "CreatePDFSignatureRequest/" + MOA
      + "SingleSignatureInfo";
  private static final String SIGNATURE_PROFILE_XPATH = MOA + "SignatureProfile";
  private static final String SIGNATURE_POSITION_XPATH = MOA + "SignaturePosition";
  private static final String SIGNATURE_ID_XPATH = MOA + "SignatureID";

  private static final String PDF_DOCUMENT_XPATH = MOA + "PDFDocument";

  /**
   * Create a new <code>CreateCMSSignatureRequestParser</code>.
   */
  public CreatePDFSignatureRequestParser() {
  }

  /**
   * Parse a <code>CreateCMSSignatureRequest</code> DOM element, as defined by the
   * MOA schema.
   * 
   * @param requestElem The <code>CreateCMSSignatureRequest</code> to parse. The
   *                    request must have been successfully parsed against the
   *                    schema for this method to succeed.
   * @return A <code>CreateCMSSignatureRequest</code> API object containing the
   *         data from the DOM element.
   * @throws MOAApplicationException An error occurred parsing the request.
   */
  public CreatePDFRequest parse(Element requestElem) throws MOAApplicationException {

    final String keyIdentifier = XPathUtils.getElementValue(requestElem, KEY_IDENTIFIER_XPATH, null);

    final CreatePDFRequest createPDFRequest = new CreatePDFRequest(keyIdentifier);
    parseSingleSignatureInfos(requestElem, createPDFRequest);

    return createPDFRequest;
  }

  /**
   * Parse all <code>SingleSignatureInfo</code> elements of the
   * <code>CreateCMSSignatureRequest</code>.
   * 
   * @param requestElem The <code>CreateCMSSignatureRequest</code> to parse.
   * @return A <code>List</code> of <code>SingleSignatureInfo</code> API objects.
   * @throws MOAApplicationException An error occurred parsing on of the
   *                                 <code>SingleSignatureInfo</code> elements.
   */
  private void parseSingleSignatureInfos(Element requestElem, CreatePDFRequest createPDFRequest)
      throws MOAApplicationException {

    final NodeIterator sigInfoElems = XPathUtils.selectNodeIterator(requestElem, SINGLE_SIGNATURE_INFO_XPATH);
    Element sigInfoElem;

    while ((sigInfoElem = (Element) sigInfoElems.nextNode()) != null) {
      createPDFRequest.getSignatureInfoList().add(parsePDFSignatureInfo(sigInfoElem));
    }
  }

  /**
   * Parse a <code>SingleSignatureInfo</code> DOM element.
   * 
   * @param sigInfoElem The <code>SingleSignatureInfo</code> DOM element to parse.
   * @return A <code>SingleSignatureInfo</code> API object containing the
   *         information of <code>sigInfoElem</code>.
   * @throws MOAApplicationException An error occurred parsing the
   *                                 <code>SingleSignatureInfo</code>.
   */
  private PDFSignatureInfo parsePDFSignatureInfo(Element sigInfoElem) throws MOAApplicationException {

    final String signatureProfile = XPathUtils.getElementValue(sigInfoElem, SIGNATURE_PROFILE_XPATH, null);
    final String signaturePosition = XPathUtils.getElementValue(sigInfoElem, SIGNATURE_POSITION_XPATH, null);
    final String signatureID = XPathUtils.getElementValue(sigInfoElem, SIGNATURE_ID_XPATH, null);

    final Element base64ContentElem = (Element) XPathUtils.selectSingleNode(sigInfoElem, PDF_DOCUMENT_XPATH);
    final String base64Str = DOMUtils.getText(base64ContentElem);
    try {
      final byte[] inputPDF = Base64Utils.decode(base64Str, true);
      final PDFSignatureInfo PDFSignatureInfo = new PDFSignatureInfo(inputPDF,
          signatureProfile, signaturePosition, signatureID);

      return PDFSignatureInfo;
    } catch (final IOException e) {
      throw new MOAApplicationException("2244", null, e);
    }

  }
}