/**
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements. See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership. The ASF licenses this file
    * to you under the Apache License, Version 2.0 (the
    * "License"); you may not use this file except in compliance
    * with the License. You may obtain a copy of the License at
    *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied. See the License for the
   * specific language governing permissions and limitations
   * under the License.
   */
  
  package org.apache.ws.security.components.crypto;
  
  import java.security.PublicKey;
  import java.security.cert.X509Certificate;
  import java.security.interfaces.DSAPublicKey;
  import java.security.interfaces.RSAPublicKey;
  import java.util.Set;
  
  import javax.xml.crypto.dsig.Reference;
  import javax.xml.crypto.dsig.Transform;
  import javax.xml.crypto.dsig.XMLSignature;
  
  import org.apache.ws.security.WSSecurityException;
  
  /**
   * Validate signature/encryption/etc. algorithms against an AlgorithmSuite policy.
   */
  public class AlgorithmSuiteValidator {
      
      private static final org.apache.commons.logging.Log LOG = 
          org.apache.commons.logging.LogFactory.getLog(AlgorithmSuiteValidator.class);
      
      private final AlgorithmSuite algorithmSuite;
      
      public AlgorithmSuiteValidator(
          AlgorithmSuite algorithmSuite
      ) {
          this.algorithmSuite = algorithmSuite;
      }
      
      /**
       * Check the Signature Method
       */
      public void checkSignatureMethod(
          String signatureMethod
      ) throws WSSecurityException {
          Set<String> allowedSignatureMethods = algorithmSuite.getSignatureMethods();
          if (!allowedSignatureMethods.isEmpty()
              && !allowedSignatureMethods.contains(signatureMethod)) {
              LOG.debug(
                  "SignatureMethod " + signatureMethod + " does not match required values"
              );
              throw new WSSecurityException(WSSecurityException.INVALID_SECURITY);
          }
      }
      
      /**
       * Check the C14n Algorithm
       */
      public void checkC14nAlgorithm(
          String c14nAlgorithm
      ) throws WSSecurityException {
          Set<String> allowedC14nAlgorithms = algorithmSuite.getC14nAlgorithms();
          if (!allowedC14nAlgorithms.isEmpty() && !allowedC14nAlgorithms.contains(c14nAlgorithm)) {
              LOG.debug(
                  "C14nMethod " + c14nAlgorithm + " does not match required value"
              );
              throw new WSSecurityException(WSSecurityException.INVALID_SECURITY);
          }
      }
      
      /**
       * Check the Signature Algorithms
       */
      public void checkSignatureAlgorithms(
          XMLSignature xmlSignature
      ) throws WSSecurityException {
          // Signature Algorithm
          String signatureMethod = 
              xmlSignature.getSignedInfo().getSignatureMethod().getAlgorithm();
          checkSignatureMethod(signatureMethod);
              
          // C14n Algorithm
          String c14nMethod = 
              xmlSignature.getSignedInfo().getCanonicalizationMethod().getAlgorithm();
          checkC14nAlgorithm(c14nMethod);
          
          for (Object refObject : xmlSignature.getSignedInfo().getReferences()) {
              Reference reference = (Reference)refObject;
              // Digest Algorithm
             String digestMethod = reference.getDigestMethod().getAlgorithm();
             Set<String> allowedDigestAlgorithms = algorithmSuite.getDigestAlgorithms();
             if (!allowedDigestAlgorithms.isEmpty()
                     && !allowedDigestAlgorithms.contains(digestMethod)) {
                 LOG.debug(
                     "DigestMethod " + digestMethod + " does not match required value"
                 );
                 throw new WSSecurityException(WSSecurityException.INVALID_SECURITY);
             }
             
             // Transform Algorithms
             for (int i = 0; i < reference.getTransforms().size(); i++) {
                 Transform transform = (Transform)reference.getTransforms().get(i);
                 String algorithm = transform.getAlgorithm();
                 Set<String> allowedTransformAlgorithms = 
                         algorithmSuite.getTransformAlgorithms();
                 if (!allowedTransformAlgorithms.isEmpty() 
                         && !allowedTransformAlgorithms.contains(algorithm)) {
                     LOG.debug(
                         "Transform method " + algorithm + " does not match required value"
                     );
                     throw new WSSecurityException(WSSecurityException.INVALID_SECURITY);
                 }
             }
         }
     }
     
     public void checkEncryptionKeyWrapAlgorithm(
         String keyWrapAlgorithm
     ) throws WSSecurityException {
         Set<String> keyWrapAlgorithms = algorithmSuite.getKeyWrapAlgorithms();
         if (!keyWrapAlgorithms.isEmpty()
             && !keyWrapAlgorithms.contains(keyWrapAlgorithm)) {
             LOG.debug(
                 "The Key transport method does not match the requirement"
             );
             throw new WSSecurityException(WSSecurityException.INVALID_SECURITY);
         }
     }
     
     public void checkSymmetricEncryptionAlgorithm(
         String symmetricAlgorithm
     ) throws WSSecurityException {
         Set<String> encryptionMethods = algorithmSuite.getEncryptionMethods();
         if (!encryptionMethods.isEmpty()
             && !encryptionMethods.contains(symmetricAlgorithm)) {
             LOG.debug(
                 "The encryption algorithm does not match the requirement"
             );
             throw new WSSecurityException(WSSecurityException.INVALID_SECURITY);
         }
     }
 
     /**
      * Check the asymmetric key length
      */
     public void checkAsymmetricKeyLength(
         X509Certificate x509Certificate
     ) throws WSSecurityException {
         if (x509Certificate == null) {
             return;
         }
         
         checkAsymmetricKeyLength(x509Certificate.getPublicKey());
     }
     
     /**
      * Check the asymmetric key length
      */
     public void checkAsymmetricKeyLength(
         PublicKey publicKey
     ) throws WSSecurityException {
         if (publicKey == null) {
             return;
         }
         if (publicKey instanceof RSAPublicKey) {
             int modulus = ((RSAPublicKey)publicKey).getModulus().bitLength();
             if (modulus < algorithmSuite.getMinimumAsymmetricKeyLength()
                 || modulus > algorithmSuite.getMaximumAsymmetricKeyLength()) {
                 LOG.debug(
                     "The asymmetric key length does not match the requirement"
                 );
                 throw new WSSecurityException(WSSecurityException.INVALID_SECURITY);
             }
         } else if (publicKey instanceof DSAPublicKey) {
             int length = ((DSAPublicKey)publicKey).getParams().getP().bitLength();
             if (length < algorithmSuite.getMinimumAsymmetricKeyLength()
                 || length > algorithmSuite.getMaximumAsymmetricKeyLength()) {
                 LOG.debug(
                     "The asymmetric key length does not match the requirement"
                 );
                 throw new WSSecurityException(WSSecurityException.INVALID_SECURITY);
             }
         } else {
             LOG.debug(
                 "An unknown public key was provided"
             );
             throw new WSSecurityException(WSSecurityException.INVALID_SECURITY);
         }
     }
     
     /**
      * Check the symmetric key length
      */
     public void checkSymmetricKeyLength(
         int secretKeyLength
     ) throws WSSecurityException {
         if (secretKeyLength < (algorithmSuite.getMinimumSymmetricKeyLength() / 8)
             || secretKeyLength > (algorithmSuite.getMaximumSymmetricKeyLength() / 8)) {
             LOG.debug(
                 "The symmetric key length does not match the requirement"
             );
             throw new WSSecurityException(WSSecurityException.INVALID_SECURITY);
         }
     }
     
     /**
      * Check Signature Derived Key length (in bytes)
      */
     public void checkSignatureDerivedKeyLength(
         int derivedKeyLength
     ) throws WSSecurityException {
         int requiredKeyLength = algorithmSuite.getSignatureDerivedKeyLength();
         if (requiredKeyLength > 0 && (derivedKeyLength / 8) != requiredKeyLength) {
             LOG.debug(
                 "The signature derived key length of " + derivedKeyLength + " does not match"
                 + "the requirement of " + requiredKeyLength
             );
         }
     }
     
     /**
      * Check Encryption Derived Key length (in bytes)
      */
     public void checkEncryptionDerivedKeyLength(
         int derivedKeyLength
     ) throws WSSecurityException {
         int requiredKeyLength = algorithmSuite.getEncryptionDerivedKeyLength();
         if (requiredKeyLength > 0 && (derivedKeyLength / 8) != requiredKeyLength) {
             LOG.debug(
                 "The encryption derived key length of " + derivedKeyLength + " does not match"
                 + "the requirement of " + requiredKeyLength
             );
         }
     }
     
     /**
      * Check Derived Key algorithm
      */
     public void checkDerivedKeyAlgorithm(
         String algorithm
     ) throws WSSecurityException {
         Set<String> derivedKeyAlgorithms = algorithmSuite.getDerivedKeyAlgorithms();
         if (!derivedKeyAlgorithms.isEmpty()
             && !derivedKeyAlgorithms.contains(algorithm)) {
             LOG.debug(
                 "The Derived Key Algorithm does not match the requirement"
             );
             throw new WSSecurityException(WSSecurityException.INVALID_SECURITY);
         }
     }
         
 }