/*
    * 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.cipher;
  
  import io.github.tonywasher.joceanus.gordianknot.api.base.GordianKeySpec;
  import io.github.tonywasher.joceanus.gordianknot.api.base.GordianLength;
  
  import java.util.Objects;
  
  /**
   * SymKey specification.
   */
  public class GordianSymKeySpec
          implements GordianKeySpec {
      /**
       * The Separator.
       */
      private static final String SEP = "-";
  
      /**
       * The SymKey Type.
       */
      private final GordianSymKeyType theSymKeyType;
  
      /**
       * The Engine Block Length.
       */
      private final GordianLength theBlockLength;
  
      /**
       * The Key Length.
       */
      private final GordianLength theKeyLength;
  
      /**
       * The Validity.
       */
      private final boolean isValid;
  
      /**
       * The String name.
       */
      private String theName;
  
      /**
       * Constructor.
       *
       * @param pSymKeyType the symKeyType
       * @param pKeyLength  the keyLength
       */
      public GordianSymKeySpec(final GordianSymKeyType pSymKeyType,
                               final GordianLength pKeyLength) {
          this(pSymKeyType, pSymKeyType.getDefaultBlockLength(), pKeyLength);
      }
  
      /**
       * Constructor.
       *
       * @param pSymKeyType  the symKeyType
       * @param pBlockLength the stateLength
       * @param pKeyLength   the keyLength
       */
      public GordianSymKeySpec(final GordianSymKeyType pSymKeyType,
                               final GordianLength pBlockLength,
                               final GordianLength pKeyLength) {
          /* Store parameters */
          theSymKeyType = pSymKeyType;
          theBlockLength = pBlockLength;
          theKeyLength = pKeyLength;
          isValid = checkValidity();
      }
  
      /**
       * Obtain symKey Type.
       *
       * @return the symKeyType
       */
      public GordianSymKeyType getSymKeyType() {
          return theSymKeyType;
      }
  
      /**
       * Obtain Block Length.
       *
       * @return the blockLength
      */
     public GordianLength getBlockLength() {
         return theBlockLength;
     }
 
     @Override
     public GordianLength getKeyLength() {
         return theKeyLength;
     }
 
     /**
      * Obtain HalfBlock length.
      *
      * @return the Length
      */
     public GordianLength getHalfBlockLength() {
         switch (theBlockLength) {
             case LEN_64:
                 return GordianLength.LEN_32;
             case LEN_128:
                 return GordianLength.LEN_64;
             case LEN_256:
                 return GordianLength.LEN_128;
             case LEN_512:
                 return GordianLength.LEN_256;
             case LEN_1024:
                 return GordianLength.LEN_512;
             default:
                 return theBlockLength;
         }
     }
 
     /**
      * Is the keySpec valid?
      *
      * @return true/false.
      */
     public boolean isValid() {
         return isValid;
     }
 
     /**
      * Check spec validity.
      *
      * @return valid true/false
      */
     private boolean checkValidity() {
         /* Everything must be non-null */
         if (theSymKeyType == null
                 || theBlockLength == null
                 || theKeyLength == null) {
             return false;
         }
 
         /* Check blockLength and keyLength validity */
         return theSymKeyType.validBlockAndKeyLengths(theBlockLength, theKeyLength);
     }
 
     @Override
     public String toString() {
         /* If we have not yet loaded the name */
         if (theName == null) {
             /* If the keySpec is valid */
             if (isValid) {
                 /* Load the name */
                 theName = theSymKeyType.toString();
                 if (theSymKeyType.hasMultipleBlockLengths()
                         && !GordianSymKeyType.THREEFISH.equals(theSymKeyType)) {
                     int myLen = theBlockLength.getLength();
                     if (GordianSymKeyType.RC5.equals(theSymKeyType)) {
                         myLen >>= 1;
                     }
                     theName += myLen;
                 }
                 theName += SEP + theKeyLength;
             } else {
                 /* Report invalid spec */
                 theName = "InvalidSymKeySpec: " + theSymKeyType + ":" + theBlockLength + ":" + theKeyLength;
             }
         }
 
         /* 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 subFields */
         return pThat instanceof GordianSymKeySpec myThat
                 && theSymKeyType == myThat.getSymKeyType()
                 && theBlockLength == myThat.getBlockLength()
                 && theKeyLength == myThat.getKeyLength();
     }
 
     @Override
     public int hashCode() {
         return Objects.hash(theSymKeyType, theBlockLength, theKeyLength);
     }
 }