/*
    * 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.jca;
  
  import io.github.tonywasher.joceanus.gordianknot.api.base.GordianException;
  import io.github.tonywasher.joceanus.gordianknot.api.keypair.GordianKeyPair;
  import io.github.tonywasher.joceanus.gordianknot.api.keypair.GordianStateAwareKeyPair;
  import io.github.tonywasher.joceanus.gordianknot.api.keypair.spec.GordianKeyPairSpec;
  import io.github.tonywasher.joceanus.gordianknot.impl.core.exc.GordianDataException;
  import io.github.tonywasher.joceanus.gordianknot.impl.core.keypair.GordianCoreKeyPair;
  import io.github.tonywasher.joceanus.gordianknot.impl.core.keypair.GordianPrivateKey;
  import io.github.tonywasher.joceanus.gordianknot.impl.core.keypair.GordianPrivateKey.GordianStateAwarePrivateKey;
  import io.github.tonywasher.joceanus.gordianknot.impl.core.keypair.GordianPublicKey;
  import org.bouncycastle.jcajce.provider.asymmetric.dh.BCDHPrivateKey;
  import org.bouncycastle.jcajce.provider.asymmetric.dh.BCDHPublicKey;
  import org.bouncycastle.jcajce.spec.DHDomainParameterSpec;
  import org.bouncycastle.pqc.jcajce.interfaces.LMSPrivateKey;
  import org.bouncycastle.pqc.jcajce.interfaces.XMSSMTPrivateKey;
  import org.bouncycastle.pqc.jcajce.interfaces.XMSSPrivateKey;
  
  import javax.crypto.spec.DHParameterSpec;
  import java.security.PrivateKey;
  import java.security.PublicKey;
  import java.util.Objects;
  
  /**
   * BouncyCastle Asymmetric KeyPair.
   */
  public class JcaKeyPair
          extends GordianCoreKeyPair {
      /**
       * Constructor.
       *
       * @param pPublic the public key
       */
      protected JcaKeyPair(final JcaPublicKey pPublic) {
          this(pPublic, null);
      }
  
      /**
       * Constructor.
       *
       * @param pPublic  the public key
       * @param pPrivate the private key
       */
      protected JcaKeyPair(final JcaPublicKey pPublic,
                           final JcaPrivateKey pPrivate) {
          super(pPublic, pPrivate);
      }
  
      @Override
      public JcaPublicKey getPublicKey() {
          return (JcaPublicKey) super.getPublicKey();
      }
  
      @Override
      public JcaPrivateKey getPrivateKey() {
          return (JcaPrivateKey) super.getPrivateKey();
      }
  
      @Override
      public JcaKeyPair getPublicOnly() {
          return new JcaKeyPair(getPublicKey());
      }
  
      /**
       * Check for jcaKeyPair.
       *
       * @param pKeyPair the keyPair to check
       * @throws GordianException on error
       */
      public static void checkKeyPair(final GordianKeyPair pKeyPair) throws GordianException {
          /* Check that it is a JcaKeyPair */
          if (!(pKeyPair instanceof JcaKeyPair)) {
              /* Reject keyPair */
              throw new GordianDataException("Invalid KeyPair");
          }
      }
  
      /**
       * Check for jcaKeyPair.
       *
       * @param pKeyPair the keyPair to check
       * @param pSpec    the required keySpec
       * @throws GordianException on error
      */
     public static void checkKeyPair(final GordianKeyPair pKeyPair,
                                     final GordianKeyPairSpec pSpec) throws GordianException {
         /* Check the keyPair */
         checkKeyPair(pKeyPair);
 
         /* Check that it the correct key type */
         if (!pSpec.equals(pKeyPair.getKeyPairSpec())) {
             /* Reject keyPair */
             throw new GordianDataException("Invalid KeyPairType");
         }
     }
 
     /**
      * Jca PublicKey.
      */
     public static class JcaPublicKey
             extends GordianPublicKey {
         /**
          * Public Key details.
          */
         private final PublicKey theKey;
 
         /**
          * Constructor.
          *
          * @param pKeySpec   the keySpec
          * @param pPublicKey the public key
          */
         protected JcaPublicKey(final GordianKeyPairSpec pKeySpec,
                                final PublicKey pPublicKey) {
             super(pKeySpec);
             theKey = pPublicKey;
         }
 
         /**
          * Obtain the public key.
          *
          * @return the key
          */
         protected PublicKey getPublicKey() {
             return theKey;
         }
 
         @Override
         public boolean equals(final Object pThat) {
             /* Handle the trivial cases */
             if (pThat == this) {
                 return true;
             }
             if (pThat == null) {
                 return false;
             }
 
             /* Make sure that the object is the same class */
             if (!(pThat instanceof JcaPublicKey myThat)) {
                 return false;
             }
 
             /* Check differences */
             return getKeySpec().equals(myThat.getKeySpec())
                     && theKey.equals(myThat.getPublicKey());
         }
 
         @Override
         public int hashCode() {
             return Objects.hash(getKeySpec(), theKey);
         }
     }
 
     /**
      * Jca PrivateKey.
      */
     public static class JcaPrivateKey
             extends GordianPrivateKey {
         /**
          * Private Key details.
          */
         private final PrivateKey theKey;
 
         /**
          * Constructor.
          *
          * @param pKeySpec    the keySpec
          * @param pPrivateKey the private key
          */
         protected JcaPrivateKey(final GordianKeyPairSpec pKeySpec,
                                 final PrivateKey pPrivateKey) {
             super(pKeySpec);
             theKey = pPrivateKey;
         }
 
         /**
          * Obtain the private key.
          *
          * @return the key
          */
         protected PrivateKey getPrivateKey() {
             return theKey;
         }
 
         @Override
         public boolean equals(final Object pThat) {
             /* Handle the trivial cases */
             if (pThat == this) {
                 return true;
             }
             if (pThat == null) {
                 return false;
             }
 
             /* Make sure that the object is the same class */
             if (!(pThat instanceof JcaPrivateKey myThat)) {
                 return false;
             }
 
             /* Check differences */
             return getKeySpec().equals(myThat.getKeySpec())
                     && theKey.equals(myThat.getPrivateKey());
         }
 
         @Override
         public int hashCode() {
             return Objects.hash(getKeySpec(), theKey);
         }
     }
 
     /**
      * Jca StateAware PrivateKey.
      */
     public static class JcaStateAwarePrivateKey
             extends JcaPrivateKey
             implements GordianStateAwarePrivateKey {
         /**
          * The private key.
          */
         private final PrivateKey thePrivateKey;
 
         /**
          * Constructor.
          *
          * @param pKeySpec the key spec
          * @param pKey     the key
          */
         JcaStateAwarePrivateKey(final GordianKeyPairSpec pKeySpec,
                                 final PrivateKey pKey) {
             super(pKeySpec, pKey);
             thePrivateKey = pKey;
         }
 
         @Override
         public PrivateKey getPrivateKey() {
             return thePrivateKey;
         }
 
         @Override
         public long getUsagesRemaining() {
             if (thePrivateKey instanceof LMSPrivateKey) {
                 return ((LMSPrivateKey) getPrivateKey()).getUsagesRemaining();
             }
             if (thePrivateKey instanceof XMSSMTPrivateKey) {
                 return ((XMSSMTPrivateKey) getPrivateKey()).getUsagesRemaining();
             }
             return thePrivateKey instanceof XMSSPrivateKey
                     ? ((XMSSPrivateKey) getPrivateKey()).getUsagesRemaining()
                     : 0;
         }
 
         @Override
         public JcaStateAwarePrivateKey getKeyShard(final int pNumUsages) {
             if (thePrivateKey instanceof LMSPrivateKey) {
                 return new JcaStateAwarePrivateKey(getKeySpec(), ((LMSPrivateKey) getPrivateKey()).extractKeyShard(pNumUsages));
             }
             if (thePrivateKey instanceof XMSSMTPrivateKey) {
                 return new JcaStateAwarePrivateKey(getKeySpec(), ((XMSSMTPrivateKey) getPrivateKey()).extractKeyShard(pNumUsages));
             }
             return thePrivateKey instanceof XMSSPrivateKey
                     ? new JcaStateAwarePrivateKey(getKeySpec(), ((XMSSPrivateKey) getPrivateKey()).extractKeyShard(pNumUsages))
                     : null;
         }
 
         @Override
         public boolean equals(final Object pThat) {
             /* Handle the trivial cases */
             if (pThat == this) {
                 return true;
             }
             if (pThat == null) {
                 return false;
             }
 
             /* Make sure that the object is the same class */
             if (!(pThat instanceof JcaStateAwarePrivateKey myThat)) {
                 return false;
             }
 
             /* Check differences */
             return getKeySpec().equals(myThat.getKeySpec())
                     && thePrivateKey.equals(myThat.getPrivateKey());
         }
 
         @Override
         public int hashCode() {
             return Objects.hash(getKeySpec(), thePrivateKey);
         }
     }
 
     /**
      * Jca DH PublicKey.
      */
     public static class JcaDHPublicKey
             extends JcaPublicKey {
         /**
          * Public Key details.
          */
         private final BCDHPublicKey theKey;
 
         /**
          * Constructor.
          *
          * @param pKeySpec   the keySpec
          * @param pPublicKey the public key
          */
         protected JcaDHPublicKey(final GordianKeyPairSpec pKeySpec,
                                  final BCDHPublicKey pPublicKey) {
             super(pKeySpec, pPublicKey);
             theKey = pPublicKey;
         }
 
         @Override
         protected BCDHPublicKey getPublicKey() {
             return theKey;
         }
 
         @Override
         public boolean equals(final Object pThat) {
             /* Handle the trivial cases */
             if (pThat == this) {
                 return true;
             }
             if (pThat == null) {
                 return false;
             }
 
             /* Make sure that the object is the same class */
             if (!(pThat instanceof JcaDHPublicKey myThat)) {
                 return false;
             }
 
             /* Check differences */
             return getKeySpec().equals(myThat.getKeySpec())
                     && theKey.getY().equals(myThat.getPublicKey().getY())
                     && dhParamsAreEqual(theKey.getParams(), myThat.getPublicKey().getParams());
         }
 
         @Override
         public int hashCode() {
             return Objects.hash(getKeySpec(), theKey);
         }
     }
 
     /**
      * check DH Parameters are equal (ignoring L!!).
      *
      * @param pFirst  the first parameters
      * @param pSecond the second parameters
      * @return true/false
      */
     private static boolean dhParamsAreEqual(final DHParameterSpec pFirst,
                                             final DHParameterSpec pSecond) {
         final DHDomainParameterSpec myFirst = (DHDomainParameterSpec) pFirst;
         final DHDomainParameterSpec mySecond = (DHDomainParameterSpec) pSecond;
         return myFirst.getP().equals(mySecond.getP())
                 && myFirst.getG().equals(mySecond.getG())
                 && myFirst.getQ().equals(mySecond.getQ());
     }
 
     /**
      * Jca DH PrivateKey.
      */
     public static class JcaDHPrivateKey
             extends JcaPrivateKey {
         /**
          * The private key.
          */
         private final BCDHPrivateKey thePrivateKey;
 
         /**
          * Constructor.
          *
          * @param pKeySpec the key spec
          * @param pKey     the key
          */
         JcaDHPrivateKey(final GordianKeyPairSpec pKeySpec,
                         final BCDHPrivateKey pKey) {
             super(pKeySpec, pKey);
             thePrivateKey = pKey;
         }
 
         @Override
         public BCDHPrivateKey getPrivateKey() {
             return thePrivateKey;
         }
 
         @Override
         public boolean equals(final Object pThat) {
             /* Handle the trivial cases */
             if (pThat == this) {
                 return true;
             }
             if (pThat == null) {
                 return false;
             }
 
             /* Make sure that the object is the same class */
             if (!(pThat instanceof JcaDHPrivateKey myThat)) {
                 return false;
             }
 
             /* Check differences */
             return getKeySpec().equals(myThat.getKeySpec())
                     && thePrivateKey.getX().equals(myThat.getPrivateKey().getX())
                     && dhParamsAreEqual(thePrivateKey.getParams(), myThat.getPrivateKey().getParams());
         }
 
         @Override
         public int hashCode() {
             return Objects.hash(getKeySpec(), thePrivateKey);
         }
     }
 
     /**
      * Jca StateAware KeyPair.
      */
     public static class JcaStateAwareKeyPair
             extends JcaKeyPair
             implements GordianStateAwareKeyPair {
         /**
          * Constructor.
          *
          * @param pPublic  the public key
          * @param pPrivate the private key
          */
         JcaStateAwareKeyPair(final JcaPublicKey pPublic,
                              final JcaStateAwarePrivateKey pPrivate) {
             super(pPublic, pPrivate);
         }
 
         @Override
         public JcaStateAwarePrivateKey getPrivateKey() {
             return (JcaStateAwarePrivateKey) super.getPrivateKey();
         }
 
         @Override
         public long getUsagesRemaining() {
             return getPrivateKey().getUsagesRemaining();
         }
 
         @Override
         public JcaStateAwareKeyPair getKeyPairShard(final int pNumUsages) {
             return new JcaStateAwareKeyPair(getPublicKey(), getPrivateKey().getKeyShard(pNumUsages));
         }
     }
 }