/*
 * 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.api.xmlbind;

import java.util.ArrayList;
import java.util.List;

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

import at.gv.egovernment.moa.spss.MOAApplicationException;
import at.gv.egovernment.moa.spss.api.SPSSFactory;
import at.gv.egovernment.moa.spss.api.common.Content;
import at.gv.egovernment.moa.spss.api.xmlsign.CreateSignatureEnvironmentProfile;
import at.gv.egovernment.moa.spss.api.xmlsign.CreateSignatureInfo;
import at.gv.egovernment.moa.spss.api.xmlsign.CreateTransformsInfoProfile;
import at.gv.egovernment.moa.spss.api.xmlsign.CreateXMLSignatureRequest;
import at.gv.egovernment.moa.spss.api.xmlsign.DataObjectInfo;
import at.gv.egovernment.moa.spss.api.xmlsign.SingleSignatureInfo;
import at.gv.egovernment.moaspss.util.BoolUtils;
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>CreateXMLSignatureRequest</code> DOM trees into
 * <code>CreateXMLSignatureRequest</code> API objects.
 *
 * @author Patrick Peck
 * @version $Id$
 */
public class CreateXMLSignatureRequestParser {

  //
  // XPath expresssions to select elements in the CreateXMLSignatureRequest
  //
  private static final String MOA = Constants.MOA_PREFIX + ":";
  private static final String KEY_IDENTIFIER_XPATH =
      "/" + MOA + "CreateXMLSignatureRequest/" + MOA + "KeyIdentifier";
  private static final String SINGLE_SIGNATURE_INFO_XPATH =
      "/" + MOA + "CreateXMLSignatureRequest/" + MOA + "SingleSignatureInfo";
  private static final String DATA_OBJECT_INFO_XPATH = MOA + "DataObjectInfo";
  private static final String DATA_OBJECT_XPATH = MOA + "DataObject";
  private static final String CREATE_SIGNATURE_INFO_XPATH =
      MOA + "CreateSignatureInfo";
  private static final String CREATE_TRANSFORMS_INFO_PROFILE_XPATH =
      MOA + "CreateTransformsInfoProfile | "
          + MOA + "CreateTransformsInfoProfileID";
  private static final String CREATE_SIGNATURE_ENVIRONMENT_XPATH =
      MOA + "CreateSignatureEnvironment";
  private static final String CREATE_SIGNATURE_ENVIRONMENT_PROFILE_XPATH =
      MOA + "CreateSignatureEnvironmentProfile | "
          + MOA + "CreateSignatureEnvironmentProfileID";
  private static final String SL_CONFORM_ATTR_NAME = "SecurityLayerConformity";

  /** The factory to create API objects. */
  private final SPSSFactory factory;

  /**
   * Create a new <code>CreateXMLSignatureRequestParser</code>.
   */
  public CreateXMLSignatureRequestParser() {
    this.factory = SPSSFactory.getInstance();
  }

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

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

    return factory.createCreateXMLSignatureRequest(
        keyIdentifier,
        singleSignatureInfos);
  }

  /**
   * Parse all <code>SingleSignatureInfo</code> elements of the
   * <code>CreateXMLSignatureRequest</code>.
   *
   * @param requestElem The <code>CreateXMLSignatureRequest</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 List parseSingleSignatureInfos(Element requestElem)
      throws MOAApplicationException {

    final List singleSignatureInfos = new ArrayList();
    final NodeIterator sigInfoElems =
        XPathUtils.selectNodeIterator(requestElem, SINGLE_SIGNATURE_INFO_XPATH);
    Element sigInfoElem;

    while ((sigInfoElem = (Element) sigInfoElems.nextNode()) != null) {
      singleSignatureInfos.add(parseSingleSignatureInfo(sigInfoElem));
    }

    return singleSignatureInfos;
  }

  /**
   * 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 SingleSignatureInfo parseSingleSignatureInfo(Element sigInfoElem)
      throws MOAApplicationException {

    final List dataObjectInfos = parseDataObjectInfos(sigInfoElem);
    final CreateSignatureInfo createSignatureInfo =
        parseCreateSignatureInfo(sigInfoElem);
    boolean securityLayerConform;

    if (sigInfoElem.hasAttribute(SL_CONFORM_ATTR_NAME)) {
      securityLayerConform =
          BoolUtils.valueOf(sigInfoElem.getAttribute(SL_CONFORM_ATTR_NAME));
    } else {
      securityLayerConform = true;
    }

    return factory.createSingleSignatureInfo(
        dataObjectInfos,
        createSignatureInfo,
        securityLayerConform);
  }

  /**
   * Parse the <code>DataObjectInfo</code> DOM elements contained in the given
   * <code>SingleSignatureInfo</code> DOM element.
   *
   * @param sigInfoElem The <code>SingleSignatureInfo</code> DOM element whose
   *                    <code>DataObjectInfo</code>s to parse.
   * @return A <code>List</code> of <code>DataObjectInfo</code> API objects
   *         containing the data from the <code>DataObjectInfo</code> DOM
   *         elements.
   * @throws MOAApplicationException An error occurred parsing one of the
   *                                 <code>DataObjectInfo</code>s.
   */
  private List parseDataObjectInfos(Element sigInfoElem)
      throws MOAApplicationException {

    final List dataObjectInfos = new ArrayList();
    final NodeIterator dataObjInfoElems =
        XPathUtils.selectNodeIterator(sigInfoElem, DATA_OBJECT_INFO_XPATH);
    Element dataObjInfoElem;

    while ((dataObjInfoElem = (Element) dataObjInfoElems.nextNode()) != null) {
      dataObjectInfos.add(parseDataObjectInfo(dataObjInfoElem));
    }
    return dataObjectInfos;
  }

  /**
   * Parse a <code>DataObjectInfo</code> DOM element.
   *
   * @param dataObjInfoElem The <code>DataObjectInfo</code> DOM element to parse.
   * @return A <code>DataObjectInfo</code> API element containing the data from
   *         <code>dataObjInfoElem</code>.
   * @throws MOAApplicationException An error occurred parsing the
   *                                 <code>DataObjectInfo</code>.
   */
  private DataObjectInfo parseDataObjectInfo(Element dataObjInfoElem)
      throws MOAApplicationException {

    final String structure = dataObjInfoElem.getAttribute("Structure");
    final Element dataObjectElem =
        (Element) XPathUtils.selectSingleNode(dataObjInfoElem, DATA_OBJECT_XPATH);
    final Content dataObject = RequestParserUtils.parseContent(dataObjectElem);
    final CreateTransformsInfoProfile createTransformsInfoProfile =
        parseCreateTransformsInfoProfile(dataObjInfoElem);
    boolean childOfManifest;

    if (dataObjInfoElem.hasAttribute("ChildOfManifest")) {
      childOfManifest =
          BoolUtils.valueOf(dataObjInfoElem.getAttribute("ChildOfManifest"));
    } else {
      childOfManifest = false;
    }

    return factory.createDataObjectInfo(
        structure,
        childOfManifest,
        dataObject,
        createTransformsInfoProfile);
  }

  /**
   * Parse a <code>CreateTransformsInfoProfile</code> DOM element.
   *
   * @param dataObjInfoElem The <code>DataObjectInfo</code> DOM element containing
   *                        the <code>CreateTransformsInfoProfile</code>.
   * @return The <code>CreateTransformsInfoProfile</code> API object containing
   *         the profile found in <code>dataObjInfoElem</code>.
   * @throws MOAApplicationException An error occurred parsing the
   *                                 <code>CreateTransformsInfoProfile</code>.
   */
  private CreateTransformsInfoProfile parseCreateTransformsInfoProfile(Element dataObjInfoElem)
      throws MOAApplicationException {

    final Element profileElem =
        (Element) XPathUtils.selectSingleNode(
            dataObjInfoElem,
            CREATE_TRANSFORMS_INFO_PROFILE_XPATH);

    if ("CreateTransformsInfoProfile".equals(profileElem.getLocalName())) {
      final ProfileParser profileParser = new ProfileParser();
      return profileParser.parseCreateTransformsInfoProfile(profileElem);

    } else {
      final String profileID = DOMUtils.getText(profileElem);
      return factory.createCreateTransformsInfoProfile(profileID);
    }
  }

  /**
   * Parse the <code>CreateSignatureInfo</code> DOM element contained in a
   * <code>SingleSignatureInfo</code>.
   *
   * @param sigInfoElem The <code>SingleSignatureInfo</code> DOM element
   *                    containing the <code>CreateSignatureInfo</code> to be
   *                    parsed.
   * @return A <code>CreateSignatureInfo</code> API object containing the data
   *         from the <code>CreateSignatureInfo</code> DOM element, or
   *         <code>null</code>, if none was found.
   */
  private CreateSignatureInfo parseCreateSignatureInfo(Element sigInfoElem) {
    final Element createInfoElem =
        (Element) XPathUtils.selectSingleNode(
            sigInfoElem,
            CREATE_SIGNATURE_INFO_XPATH);

    if (createInfoElem != null) {
      final Element environmentElem =
          (Element) XPathUtils.selectSingleNode(
              createInfoElem,
              CREATE_SIGNATURE_ENVIRONMENT_XPATH);
      final Content environment = RequestParserUtils.parseContent(environmentElem);
      final CreateSignatureEnvironmentProfile environmentProfile =
          parseCreateSignatureEnvironmentProfile(createInfoElem);

      return factory.createCreateSignatureInfo(environment, environmentProfile);
    } else {
      return null;
    }
  }

  /**
   * Parse the <code>CreateSignatureEnvironmentProfile</code> contained in the
   * given <code>CreateSignatureInfo</code> DOM element.
   *
   * @param createInfoElem <code>CreateSignatureInfo</code> DOM element to parse.
   * @return The <code>CreateSignatureEnvironmentProfile</code> contained in the
   *         given <code>CreateSignatureInfo</code> DOM element..
   */
  private CreateSignatureEnvironmentProfile parseCreateSignatureEnvironmentProfile(Element createInfoElem) {
    final Element profileElem =
        (Element) XPathUtils.selectSingleNode(
            createInfoElem,
            CREATE_SIGNATURE_ENVIRONMENT_PROFILE_XPATH);

    if ("CreateSignatureEnvironmentProfile"
        .equals(profileElem.getLocalName())) {
      final ProfileParser profileParser = new ProfileParser();
      return profileParser.parseCreateSignatureEnvironmentProfile(profileElem);
    } else {
      final String profileID = DOMUtils.getText(profileElem);
      return factory.createCreateSignatureEnvironmentProfile(profileID);
    }
  }

}