/*
    * GordianKnot: Security Suite
    * Copyright 2012-2026. Tony Washer
    *
    * Licensed 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 io.github.tonywasher.joceanus.gordianknot.impl.ext.macs;
  
  import io.github.tonywasher.joceanus.gordianknot.impl.ext.digests.GordianBlake2Base;
  import io.github.tonywasher.joceanus.gordianknot.impl.ext.params.GordianBlake2Parameters;
  import io.github.tonywasher.joceanus.gordianknot.impl.ext.params.GordianBlake2Parameters.GordianBlake2ParametersBuilder;
  import org.bouncycastle.crypto.CipherParameters;
  import org.bouncycastle.crypto.Mac;
  import org.bouncycastle.crypto.params.KeyParameter;
  
  /**
   * Bouncy implementation of Blake2Mac.
   */
  public class GordianBlake2Mac
          implements Mac {
      /**
       * Digest.
       */
      private final GordianBlake2Base theDigest;
  
      /**
       * Create a blake2Mac with the specified digest.
       *
       * @param pDigest the base digest.
       */
      public GordianBlake2Mac(final GordianBlake2Base pDigest) {
          theDigest = pDigest;
      }
  
      @Override
      public String getAlgorithmName() {
          return theDigest.getAlgorithmName() + "Mac";
      }
  
      @Override
      public void init(final CipherParameters pParams) {
          CipherParameters myParams = pParams;
          if (myParams instanceof KeyParameter keyParam) {
              myParams = new GordianBlake2ParametersBuilder()
                      .setKey(keyParam.getKey())
                      .build();
          }
          if (!(myParams instanceof GordianBlake2Parameters myBlakeParams)) {
              throw new IllegalArgumentException("Invalid parameter passed to Blake2Mac init - "
                      + pParams.getClass().getName());
          }
          if (myBlakeParams.getKey() == null) {
              throw new IllegalArgumentException("Blake2Mac requires a key parameter.");
          }
  
          /* Configure the digest */
          theDigest.init(myBlakeParams);
      }
  
      @Override
      public int getMacSize() {
          return theDigest.getDigestSize();
      }
  
      @Override
      public void update(final byte in) {
          theDigest.update(in);
      }
  
      @Override
      public void update(final byte[] in, final int inOff, final int len) {
          theDigest.update(in, inOff, len);
      }
  
      @Override
      public int doFinal(final byte[] out, final int outOff) {
          return theDigest.doFinal(out, outOff);
      }
  
      @Override
      public void reset() {
          theDigest.reset();
      }
  }