/*
    * 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.random;
  
  import io.github.tonywasher.joceanus.gordianknot.api.cipher.GordianSymKeySpec;
  import io.github.tonywasher.joceanus.gordianknot.api.digest.GordianDigestSpec;
  
  import java.util.Objects;
  
  /**
   * SecureRandom Specification.
   */
  public class GordianRandomSpec {
      /**
       * The Separator.
       */
      private static final String SEP = "-";
  
      /**
       * The RandomType.
       */
      private final GordianRandomType theRandomType;
  
      /**
       * The SubSpec.
       */
      private final Object theSubSpec;
  
      /**
       * Is the secureRandom predicationResistant?
       */
      private final boolean isPredictionResistant;
  
      /**
       * The Validity.
       */
      private final boolean isValid;
  
      /**
       * The String name.
       */
      private String theName;
  
      /**
       * Constructor.
       *
       * @param pRandomType the randomType
       * @param pSubSpec    the subSpec
       * @param pResistant  is the secureRandom predicationResistant?
       */
      public GordianRandomSpec(final GordianRandomType pRandomType,
                               final Object pSubSpec,
                               final boolean pResistant) {
          theRandomType = pRandomType;
          theSubSpec = pSubSpec;
          isPredictionResistant = pResistant;
          isValid = checkValidity();
      }
  
      /**
       * Obtain the randomType.
       *
       * @return the randomType.
       */
      public GordianRandomType getRandomType() {
          return theRandomType;
      }
  
      /**
       * Obtain the subSpec.
       *
       * @return the subSpec.
       */
      private Object getSubSpec() {
          return theSubSpec;
      }
  
      /**
       * Is the macSpec valid?
       *
       * @return true/false.
       */
      public boolean isValid() {
          return isValid;
      }
 
     /**
      * Obtain the digestSpec.
      *
      * @return the digestSpec.
      */
     public GordianDigestSpec getDigestSpec() {
         return theSubSpec instanceof GordianDigestSpec mySpec
                 ? mySpec
                 : null;
     }
 
     /**
      * Obtain the symKeySpec.
      *
      * @return the symKeySpec.
      */
     public GordianSymKeySpec getSymKeySpec() {
         return theSubSpec instanceof GordianSymKeySpec mySpec
                 ? mySpec
                 : null;
     }
 
     /**
      * Obtain the predication resistance.
      *
      * @return the resistance.
      */
     public boolean isPredictionResistant() {
         return isPredictionResistant;
     }
 
     /**
      * Check spec validity.
      *
      * @return valid true/false
      */
     private boolean checkValidity() {
         if (theRandomType == null) {
             return false;
         }
         switch (theRandomType) {
             case HMAC:
             case HASH:
                 return theSubSpec instanceof GordianDigestSpec mySpec
                         && mySpec.isValid()
                         && mySpec.getDigestType().supportsLargeData();
             case CTR:
             case X931:
                 return theSubSpec instanceof GordianSymKeySpec mySpec
                         && mySpec.isValid();
             default:
                 return false;
         }
     }
 
     @Override
     public String toString() {
         /* If we have not yet loaded the name */
         if (theName == null) {
             /* If the randomSpec is valid */
             if (isValid) {
                 /* Load the name */
                 theName = theRandomType.toString();
                 theName += SEP + theSubSpec;
                 if (isPredictionResistant) {
                     theName += SEP + "resistant";
                 }
             } else {
                 /* Report invalid spec */
                 theName = "InvalidRandomSpec: " + theRandomType + ":" + theSubSpec + ":" + isPredictionResistant;
             }
         }
 
         /* 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;
         }
 
         /* Check KeyType, prediction and subSpec */
         return pThat instanceof GordianRandomSpec myThat
                 && theRandomType == myThat.getRandomType()
                 && isPredictionResistant == myThat.isPredictionResistant()
                 && Objects.equals(theSubSpec, myThat.getSubSpec());
     }
 
     @Override
     public int hashCode() {
         return Objects.hash(theRandomType, theSubSpec, isPredictionResistant);
     }
 }