/**
    * 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.wss4j.common.util;
  
  import java.io.IOException;
  import java.nio.charset.StandardCharsets;
  import java.security.MessageDigest;
  import java.security.NoSuchAlgorithmException;
  
  import javax.security.auth.callback.Callback;
  import javax.security.auth.callback.CallbackHandler;
  import javax.security.auth.callback.UnsupportedCallbackException;
  
  import org.apache.wss4j.common.ext.WSPasswordCallback;
  import org.apache.wss4j.common.ext.WSSecurityException;
  import org.apache.xml.security.stax.ext.XMLSecurityConstants;
  
  public final class UsernameTokenUtil {
      public static final int DEFAULT_ITERATION = 1000;
  
      private static final org.slf4j.Logger LOG =
              org.slf4j.LoggerFactory.getLogger(UsernameTokenUtil.class);
  
      private UsernameTokenUtil() {
          // complete
      }
  
      /**
       * This static method generates a derived key as defined in WSS Username
       * Token Profile.
       *
       * @param password The password to include in the key generation
       * @param salt The Salt value
       * @param iteration The Iteration value. If zero (0) is given the method uses the
       *                  default value
       * @return Returns the derived key a byte array
       * @throws WSSecurityException
       */
      public static byte[] generateDerivedKey(
          byte[] password,
          byte[] salt,
          int iteration
      ) throws WSSecurityException {
          byte[] pwSalt = new byte[salt.length + password.length];
          System.arraycopy(password, 0, pwSalt, 0, password.length);
          System.arraycopy(salt, 0, pwSalt, password.length, salt.length);
  
          MessageDigest sha = null;
          try {
              sha = MessageDigest.getInstance("SHA1");
          } catch (NoSuchAlgorithmException e) {
              LOG.debug(e.getMessage(), e);
              throw new WSSecurityException(
                  WSSecurityException.ErrorCode.FAILURE, e, "decoding.general"
              );
          }
          //
          // Make the first hash round with start value
          //
          byte[] k = sha.digest(pwSalt);
          //
          // Perform the 1st up to iteration-1 hash rounds
          //
          int iter = iteration;
          if (iter <= 0) {
              iter = DEFAULT_ITERATION;
          }
          for (int i = 1; i < iter; i++) {
              k = sha.digest(k);
          }
          return k;
      }
  
      /**
       * This static method generates a derived key as defined in WSS Username
       * Token Profile.
       *
       * @param password The password to include in the key generation
       * @param salt The Salt value
       * @param iteration The Iteration value. If zero (0) is given the method uses the
       *                  default value
       * @return Returns the derived key a byte array
      * @throws WSSecurityException
      */
     public static byte[] generateDerivedKey(
         String password,
         byte[] salt,
         int iteration
     ) throws WSSecurityException {
         return generateDerivedKey(password.getBytes(StandardCharsets.UTF_8), salt, iteration);
     }
 
     /**
      * This static method generates a 128 bit salt value as defined in WSS
      * Username Token Profile.
      *
      * @param useForMac If <code>true</code> define the Salt for use in a MAC
      * @return Returns the 128 bit salt value as byte array
      */
     public static byte[] generateSalt(boolean useForMac) {
         byte[] saltValue = null;
         try {
             saltValue = generateNonce(16);
         } catch (WSSecurityException ex) {
             LOG.debug(ex.getMessage(), ex);
             return new byte[0];
         }
         if (useForMac) {
             saltValue[0] = 0x01;
         } else {
             saltValue[0] = 0x02;
         }
         return saltValue;
     }
 
     /**
      * Generate a nonce of the given length using a secure random algorithm. The SecureRandom
      * instance that backs this method is cached for efficiency.
      *
      * @return a nonce of the given length
      * @throws WSSecurityException
      */
     public static byte[] generateNonce(int length) throws WSSecurityException {
         try {
             return XMLSecurityConstants.generateBytes(length);
         } catch (Exception ex) {
             throw new WSSecurityException(WSSecurityException.ErrorCode.FAILURE, ex,
                     "empty", new Object[] {"Error in generating nonce of length " + length}
             );
         }
     }
 
     public static String doPasswordDigest(byte[] nonce, String created, String password) throws WSSecurityException {
         return doPasswordDigest(nonce, created, password.getBytes(StandardCharsets.UTF_8));
     }
 
     public static String doPasswordDigest(byte[] nonce, String created, byte[] password) throws WSSecurityException {
         byte[] digestBytes = doRawPasswordDigest(nonce, created, password);
         return org.apache.xml.security.utils.XMLUtils.encodeToString(digestBytes);
     }
 
     public static byte[] doRawPasswordDigest(byte[] nonce, String created, byte[] password) throws WSSecurityException {
         try {
             byte[] b1 = nonce != null ? nonce : new byte[0];
             byte[] b2 = created != null ? created.getBytes(StandardCharsets.UTF_8) : new byte[0];
             byte[] b3 = password;
             byte[] b4 = new byte[b1.length + b2.length + b3.length];
             int offset = 0;
             System.arraycopy(b1, 0, b4, offset, b1.length);
             offset += b1.length;
 
             System.arraycopy(b2, 0, b4, offset, b2.length);
             offset += b2.length;
 
             System.arraycopy(b3, 0, b4, offset, b3.length);
 
             return KeyUtils.generateDigest(b4);
         } catch (Exception e) {
             LOG.debug(e.getMessage(), e);
             throw new WSSecurityException(WSSecurityException.ErrorCode.FAILURE, e, "decoding.general");
         }
     }
 
     /**
      * Get the raw (plain text) password used to compute secret key.
      */
     public static String getRawPassword(CallbackHandler callbackHandler, String username,
                                         String password, String passwordType) throws WSSecurityException {
         if (callbackHandler == null) {
             LOG.debug("CallbackHandler is null");
             throw new WSSecurityException(WSSecurityException.ErrorCode.FAILED_AUTHENTICATION);
         }
 
         WSPasswordCallback pwCb =
             new WSPasswordCallback(
                 username, password, passwordType, WSPasswordCallback.USERNAME_TOKEN
             );
         try {
             callbackHandler.handle(new Callback[]{pwCb});
         } catch (IOException | UnsupportedCallbackException e) {
             LOG.debug(e.getMessage(), e);
             throw new WSSecurityException(
                 WSSecurityException.ErrorCode.FAILED_AUTHENTICATION, e
             );
         }
         return pwCb.getPassword();
     }
 }