/*
    * GordianKnot: Security Suite
    * Copyright 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.bc.sign;
  
  import io.github.tonywasher.joceanus.gordianknot.api.base.GordianException;
  import io.github.tonywasher.joceanus.gordianknot.api.digest.spec.GordianDigestSpec;
  import io.github.tonywasher.joceanus.gordianknot.api.sign.spec.GordianSignatureSpec;
  import io.github.tonywasher.joceanus.gordianknot.impl.bc.digest.BouncyDigest;
  import io.github.tonywasher.joceanus.gordianknot.impl.bc.keypair.BouncyKeyPair;
  import io.github.tonywasher.joceanus.gordianknot.impl.core.base.GordianBaseFactory;
  import io.github.tonywasher.joceanus.gordianknot.impl.core.sign.GordianCoreSignature;
  import io.github.tonywasher.joceanus.gordianknot.impl.core.spec.sign.GordianCoreSignatureSpec;
  import org.bouncycastle.crypto.Digest;
  import org.bouncycastle.crypto.digests.NullDigest;
  
  /**
   * Digest signature base.
   */
  public abstract class BouncyDigestSignature
          extends GordianCoreSignature {
      /**
       * The Digest.
       */
      private BouncyDigest theDigest;
  
      /**
       * Constructor.
       *
       * @param pFactory the factory
       * @param pSpec    the signatureSpec.
       * @throws GordianException on error
       */
      BouncyDigestSignature(final GordianBaseFactory pFactory,
                            final GordianSignatureSpec pSpec) throws GordianException {
          super(pFactory, pSpec);
          theDigest = pSpec.getSignatureSpec() == null
                  ? new BouncyDigest(null, new NullDigest())
                  : (BouncyDigest) getDigestFactory().createDigest(((GordianCoreSignatureSpec) pSpec).getDigestSpec());
      }
  
      /**
       * Constructor.
       *
       * @param pFactory the factory
       * @param pSpec    the signatureSpec.
       * @param pDigest  the digest
       */
      BouncyDigestSignature(final GordianBaseFactory pFactory,
                            final GordianSignatureSpec pSpec,
                            final Digest pDigest) {
          super(pFactory, pSpec);
          theDigest = new BouncyDigest(((GordianCoreSignatureSpec) pSpec).getDigestSpec(), pDigest);
      }
  
      /**
       * Set the digest.
       *
       * @param pSpec the digestSpec.
       * @throws GordianException on error
       */
      protected void setDigest(final GordianDigestSpec pSpec) throws GordianException {
          theDigest = pSpec == null
                  ? new BouncyDigest(null, new NullDigest())
                  : (BouncyDigest) getDigestFactory().createDigest(pSpec);
      }
  
      @Override
      public void update(final byte[] pBytes,
                         final int pOffset,
                         final int pLength) {
          theDigest.update(pBytes, pOffset, pLength);
      }
  
      @Override
      public void update(final byte pByte) {
          theDigest.update(pByte);
      }
  
      @Override
      public void reset() {
          theDigest.reset();
      }
  
      /**
      * Obtain the calculated digest.
      *
      * @return the digest.
      */
     protected byte[] getDigest() {
         return theDigest.finish();
     }
 
     @Override
     protected BouncyKeyPair getKeyPair() {
         return (BouncyKeyPair) super.getKeyPair();
     }
 }