package org.apache.xml.security.keys.keyresolver.implementations;

import org.apache.xml.security.exceptions.XMLSecurityException;
import org.apache.xml.security.keys.content.DEREncodedKeyValue;
import org.apache.xml.security.keys.keyresolver.KeyResolverException;
import org.apache.xml.security.keys.keyresolver.KeyResolverSpi;
import org.apache.xml.security.keys.storage.StorageResolver;
import org.apache.xml.security.utils.Constants;
import org.apache.xml.security.utils.XMLUtils;
import org.w3c.dom.Element;

import javax.crypto.SecretKey;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.cert.X509Certificate;

/**
 * KeyResolverSpi implementation which resolves public keys from a
 * <code>dsig11:DEREncodedKeyValue</code> element.
 *
 * @author Brent Putman (putmanb@georgetown.edu)
 */
public class DEREncodedKeyValueResolver extends KeyResolverSpi {

  /**
   * {@link org.apache.commons.logging} logging facility
   */
  private static org.apache.commons.logging.Log log =
    org.apache.commons.logging.LogFactory.getLog(DEREncodedKeyValueResolver.class);

  /**
   * {@inheritDoc}.
   */
  public boolean engineCanResolve(Element element, String baseURI, StorageResolver storage) {
    return XMLUtils.elementIsInSignature11Space(element, Constants._TAG_DERENCODEDKEYVALUE);
  }

  /**
   * {@inheritDoc}.
   */
  public PublicKey engineLookupAndResolvePublicKey(Element element, String baseURI, StorageResolver storage)
    throws KeyResolverException {

    if (log.isDebugEnabled()) {
      log.debug("Can I resolve " + element.getTagName());
    }

    if (!engineCanResolve(element, baseURI, storage)) {
      return null;
    }

    try {
      DEREncodedKeyValue derKeyValue = new DEREncodedKeyValue(element, baseURI);
      return derKeyValue.getPublicKey();
    } catch (XMLSecurityException e) {
      if (log.isDebugEnabled()) {
        log.debug("XMLSecurityException", e);
      }
    }

    return null;
  }

  /**
   * {@inheritDoc}.
   */
  public X509Certificate engineLookupResolveX509Certificate(Element element, String baseURI, StorageResolver storage)
    throws KeyResolverException {
    return null;
  }

  /**
   * {@inheritDoc}.
   */
  public SecretKey engineLookupAndResolveSecretKey(Element element, String baseURI, StorageResolver storage)
    throws KeyResolverException {
    return null;
  }

  /**
   * {@inheritDoc}.
   */
  public PrivateKey engineLookupAndResolvePrivateKey(Element element, String baseURI, StorageResolver storage)
    throws KeyResolverException {
    return null;
  }


}