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.util.BoolUtils;
import at.gv.egovernment.moa.util.Constants;
import at.gv.egovernment.moa.util.DOMUtils;
import at.gv.egovernment.moa.util.XPathUtils;

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;

/**
 * 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 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 {

    List singleSignatureInfos = parseSingleSignatureInfos(requestElem);
    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 {

    List singleSignatureInfos = new ArrayList();
    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 {

    List dataObjectInfos = parseDataObjectInfos(sigInfoElem);
    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 {

    List dataObjectInfos = new ArrayList();
    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 {

    String structure = dataObjInfoElem.getAttribute("Structure");
    Element dataObjectElem =
      (Element) XPathUtils.selectSingleNode(dataObjInfoElem, DATA_OBJECT_XPATH);
    Content dataObject = RequestParserUtils.parseContent(dataObjectElem);
    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 {

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

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

    } else {
      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) {
    Element createInfoElem =
      (Element) XPathUtils.selectSingleNode(
        sigInfoElem,
        CREATE_SIGNATURE_INFO_XPATH);

    if (createInfoElem != null) {
      Element environmentElem =
        (Element) XPathUtils.selectSingleNode(
          createInfoElem,
          CREATE_SIGNATURE_ENVIRONMENT_XPATH);
      Content environment = RequestParserUtils.parseContent(environmentElem);
      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) {
    Element profileElem =
      (Element) XPathUtils.selectSingleNode(
        createInfoElem,
        CREATE_SIGNATURE_ENVIRONMENT_PROFILE_XPATH);

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

}