/*
    * 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.GordianLength;
  
  import java.util.Objects;
  
  /**
   * The SymCipherSpec class.
   */
  public class GordianSymCipherSpec
          extends GordianCipherSpec<GordianSymKeySpec> {
      /**
       * The IV length.
       */
      public static final int AADIVLEN = 12;
  
      /**
       * The Separator.
       */
      private static final String SEP = "-";
  
      /**
       * Cipher Mode.
       */
      private final GordianCipherMode theMode;
  
      /**
       * Cipher Padding.
       */
      private final GordianPadding thePadding;
  
      /**
       * The Validity.
       */
      private final boolean isValid;
  
      /**
       * The String name.
       */
      private String theName;
  
      /**
       * Constructor.
       *
       * @param pKeySpec the keySpec
       * @param pMode    the mode
       * @param pPadding the padding
       */
      public GordianSymCipherSpec(final GordianSymKeySpec pKeySpec,
                                  final GordianCipherMode pMode,
                                  final GordianPadding pPadding) {
          super(pKeySpec);
          theMode = pMode;
          thePadding = pPadding;
          isValid = checkValidity();
      }
  
      /**
       * Obtain the cipherMode.
       *
       * @return the mode
       */
      public GordianCipherMode getCipherMode() {
          return theMode;
      }
  
      /**
       * Obtain the padding.
       *
       * @return the padding
       */
      public GordianPadding getPadding() {
          return thePadding;
      }
  
      @Override
      public boolean isValid() {
          return isValid;
      }
  
      @Override
      public boolean needsIV() {
          return theMode.needsIV();
     }
 
     /**
      * Obtain the blockLength.
      *
      * @return the blockLength
      */
     public GordianLength getBlockLength() {
         return getKeyType().getBlockLength();
     }
 
     @Override
     public int getIVLength() {
         if (getCipherMode().isAAD()) {
             return AADIVLEN;
         }
         final int myBlockLen = getKeyType().getBlockLength().getByteLength();
         return GordianCipherMode.G3413CTR.equals(theMode)
                 ? myBlockLen >> 1
                 : myBlockLen;
     }
 
     /**
      * Is this an AAD mode?
      *
      * @return true/false
      */
     public boolean isAAD() {
         return theMode != null && theMode.isAAD();
     }
 
     @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 = super.toString();
                 theName += SEP + theMode;
                 if (!GordianPadding.NONE.equals(thePadding)) {
                     theName += SEP + thePadding;
                 }
             } else {
                 /* Report invalid spec */
                 theName = "InvalidSymCipherSpec: " + super.toString() + ":" + theMode + ":" + thePadding;
             }
         }
 
         /* return the name */
         return theName;
     }
 
     /**
      * Check spec validity.
      *
      * @return valid true/false
      */
     private boolean checkValidity() {
         final GordianSymKeySpec mySpec = getKeyType();
         return mySpec != null && mySpec.isValid()
                 && theMode != null && thePadding != null;
     }
 
     @Override
     public boolean equals(final Object pThat) {
         /* Handle the trivial cases */
         if (this == pThat) {
             return true;
         }
         if (pThat == null) {
             return false;
         }
 
         /* Check KeyType, Mode and padding */
         return pThat instanceof GordianSymCipherSpec myThat
                 && getKeyType().equals(myThat.getKeyType())
                 && theMode == myThat.getCipherMode()
                 && thePadding == myThat.getPadding();
     }
 
     @Override
     public int hashCode() {
         return Objects.hash(getKeyType(), theMode, thePadding);
     }
 }