/*
    * 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.api.encrypt;
  
  import io.github.tonywasher.joceanus.gordianknot.api.base.GordianLength;
  import io.github.tonywasher.joceanus.gordianknot.api.digest.GordianDigestSpec;
  import io.github.tonywasher.joceanus.gordianknot.api.digest.GordianDigestSpecBuilder;
  
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Objects;
  
  /**
   * SM2 EncryptionSpec.
   */
  public class GordianSM2EncryptionSpec {
      /**
       * EncryptionType.
       */
      private final GordianSM2EncryptionType theType;
  
      /**
       * DigestSpec.
       */
      private final GordianDigestSpec theDigest;
  
      /**
       * The Validity.
       */
      private final boolean isValid;
  
      /**
       * The String name.
       */
      private String theName;
  
      /**
       * Constructor.
       *
       * @param pType   the encryptionType
       * @param pDigest the digestSpec
       */
      GordianSM2EncryptionSpec(final GordianSM2EncryptionType pType,
                               final GordianDigestSpec pDigest) {
          /* Store parameters */
          theType = pType;
          theDigest = pDigest;
          isValid = checkValidity();
      }
  
      /**
       * Create SM2 C1C2C3 Spec.
       *
       * @param pSpec the digestSpec
       * @return the encryptionSpec
       */
      public static GordianSM2EncryptionSpec c1c2c3(final GordianDigestSpec pSpec) {
          return new GordianSM2EncryptionSpec(GordianSM2EncryptionType.C1C2C3, pSpec);
      }
  
      /**
       * Create SM2 C1C2C3 Spec.
       *
       * @param pSpec the digestSpec
       * @return the encryptionSpec
       */
      public static GordianSM2EncryptionSpec c1c3c2(final GordianDigestSpec pSpec) {
          return new GordianSM2EncryptionSpec(GordianSM2EncryptionType.C1C3C2, pSpec);
      }
  
      /**
       * Obtain the encryptionType.
       *
       * @return the encryptionType
       */
      public GordianSM2EncryptionType getEncryptionType() {
          return theType;
      }
  
      /**
       * Obtain the digestSpec.
       *
       * @return the digestSpec
       */
      public GordianDigestSpec getDigestSpec() {
         return theDigest;
     }
 
     /**
      * Is the keySpec valid?
      *
      * @return true/false.
      */
     public boolean isValid() {
         return isValid;
     }
 
     /**
      * Check spec validity.
      *
      * @return valid true/false
      */
     private boolean checkValidity() {
         return theType != null
                 && theDigest != null
                 && isDigestSupported();
     }
 
     /**
      * Is the SM2 digestSpec supported?
      *
      * @return true/false
      */
     private boolean isDigestSupported() {
         switch (theDigest.getDigestType()) {
             case SHA2:
                 return !theDigest.isSha2Hybrid();
             case WHIRLPOOL:
             case SM3:
                 return true;
             case BLAKE2:
                 return theDigest.getDigestLength().equals(theDigest.getDigestState().getLength());
             default:
                 return false;
         }
     }
 
     @Override
     public String toString() {
         /* If we have not yet loaded the name */
         if (theName == null) {
             /* If the encryptionSpec is valid */
             if (isValid) {
                 /* Load the name */
                 theName = theType.toString() + GordianEncryptorSpec.SEP + theDigest.toString();
             } else {
                 /* Report invalid spec */
                 theName = "InvalidEncryptorSpec: " + theType + ":" + theDigest;
             }
         }
 
         /* return the name */
         return theName;
     }
 
     @Override
     public boolean equals(final Object pThat) {
         /* Handle the trivial cases */
         if (this == pThat) {
             return true;
         }
         if (pThat == null) {
             return false;
         }
 
         /* Make sure that the object is an EncryptorSpec */
         if (pThat.getClass() != this.getClass()) {
             return false;
         }
 
         /* Access the target encryptionSpec */
         final GordianSM2EncryptionSpec myThat = (GordianSM2EncryptionSpec) pThat;
 
         /* Match fields */
         return theType == myThat.getEncryptionType()
                 && Objects.equals(theDigest, myThat.getDigestSpec());
     }
 
     @Override
     public int hashCode() {
         return Objects.hash(theType, theDigest);
     }
 
     /**
      * Obtain a list of all possible encryptionSpecs.
      *
      * @return the list
      */
     public static List<GordianSM2EncryptionSpec> listPossibleSpecs() {
         /* Create list */
         final List<GordianSM2EncryptionSpec> mySpecs = new ArrayList<>();
 
         /* Loop through the encryptionTypes */
         for (GordianSM2EncryptionType myType : GordianSM2EncryptionType.values()) {
             mySpecs.add(new GordianSM2EncryptionSpec(myType, GordianDigestSpecBuilder.sm3()));
             mySpecs.add(new GordianSM2EncryptionSpec(myType, GordianDigestSpecBuilder.sha2(GordianLength.LEN_224)));
             mySpecs.add(new GordianSM2EncryptionSpec(myType, GordianDigestSpecBuilder.sha2(GordianLength.LEN_256)));
             mySpecs.add(new GordianSM2EncryptionSpec(myType, GordianDigestSpecBuilder.sha2(GordianLength.LEN_384)));
             mySpecs.add(new GordianSM2EncryptionSpec(myType, GordianDigestSpecBuilder.sha2(GordianLength.LEN_512)));
             mySpecs.add(new GordianSM2EncryptionSpec(myType, GordianDigestSpecBuilder.blake2s(GordianLength.LEN_256)));
             mySpecs.add(new GordianSM2EncryptionSpec(myType, GordianDigestSpecBuilder.blake2b(GordianLength.LEN_512)));
             mySpecs.add(new GordianSM2EncryptionSpec(myType, GordianDigestSpecBuilder.whirlpool()));
         }
 
         /* Return the list */
         return mySpecs;
     }
 
     /**
      * SM2 EncryptionType.
      */
     public enum GordianSM2EncryptionType {
         /**
          * C1C2C3.
          */
         C1C2C3,
 
         /**
          * C1C3C2.
          */
         C1C3C2;
     }
 }