/*
    * Metis: Java Data Framework
    * 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.metis.data;
  
  import java.util.Arrays;
  
  /**
   * Difference enum and utility.
   */
  public enum MetisDataDifference {
      /**
       * Identical.
       */
      IDENTICAL,
  
      /**
       * Value Changed.
       */
      DIFFERENT,
  
      /**
       * Security Changed.
       */
      SECURITY;
  
      /**
       * Difference interface.
       */
      @FunctionalInterface
      public interface MetisDataDiffers {
          /**
           * Test for difference with another object.
           *
           * @param pThat the other object
           * @return the difference
           */
          MetisDataDifference differs(Object pThat);
      }
  
      /**
       * The String name.
       */
      private String theName;
  
      @Override
      public String toString() {
          /* If we have not yet loaded the name */
          if (theName == null) {
              /* Load the name */
              theName = MetisDataResource.getKeyForDifference(this).getValue();
          }
  
          /* return the name */
          return theName;
      }
  
      /**
       * Is there differences?
       *
       * @return true/false
       */
      public boolean isDifferent() {
          return !IDENTICAL.equals(this);
      }
  
      /**
       * Is there no differences?
       *
       * @return true/false
       */
      public boolean isIdentical() {
          return !isDifferent();
      }
  
      /**
       * Is there value differences?
       *
       * @return true/false
       */
      public boolean isValueChanged() {
          return DIFFERENT.equals(this);
      }
  
      /**
       * Is there security differences?
      *
      * @return true/false
      */
     public boolean isSecurityChanged() {
         return SECURITY.equals(this);
     }
 
     /**
      * Combine Differences.
      *
      * @param pThat the difference to combine
      * @return the combined difference
      */
     public MetisDataDifference combine(final MetisDataDifference pThat) {
         switch (this) {
             case IDENTICAL:
                 return pThat;
             case SECURITY:
                 return (pThat == DIFFERENT)
                         ? pThat
                         : this;
             default:
                 return this;
         }
     }
 
     /**
      * Determine whether two Generic objects differ.
      *
      * @param pCurr The current object
      * @param pNew  The new object
      * @return the Difference between the objects
      */
     public static MetisDataDifference difference(final Object pCurr,
                                                  final Object pNew) {
         /* Handle identity */
         if (pCurr == pNew) {
             return IDENTICAL;
         }
 
         /* Neither value can be null */
         if (pCurr == null
                 || pNew == null) {
             return DIFFERENT;
         }
 
         /* Handle class differences */
         if (!pCurr.getClass().equals(pNew.getClass())) {
             return DIFFERENT;
         }
 
         /* Handle differs support */
         if (pCurr instanceof MetisDataDiffers myDiffers) {
             return myDiffers.differs(pNew);
         }
 
         /* Handle Standard cases */
         return pCurr.equals(pNew)
                 ? IDENTICAL
                 : DIFFERENT;
     }
 
     /**
      * Determine whether two Generic objects are equal.
      *
      * @param pCurr The current object
      * @param pNew  The new object
      * @return true/false
      */
     public static boolean isEqual(final Object pCurr,
                                   final Object pNew) {
         /* Handle identity */
         if (pCurr == pNew) {
             return true;
         }
 
         /* Neither value can be null */
         if (pCurr == null
                 || pNew == null) {
             return false;
         }
 
         /* Handle class differences */
         final Class<?> myClass = pCurr.getClass();
         if (!myClass.equals(pNew.getClass())) {
             return false;
         }
 
         /* Handle arrays */
         if (myClass.isArray()) {
             /* Handle special cases for efficiency */
             if (pCurr instanceof byte[] ba) {
                 return Arrays.equals(ba, (byte[]) pNew);
             }
             if (pCurr instanceof char[] ca) {
                 return Arrays.equals(ca, (char[]) pNew);
             }
 
             /* Handle generic arrays */
             return Arrays.equals((Object[]) pCurr, (Object[]) pNew);
         }
 
         /* Handle Standard cases */
         return pCurr.equals(pNew);
     }
 
     /**
      * Compare two similar objects for order.
      *
      * @param <X>   the object type
      * @param pCurr The current object
      * @param pNew  The new object
      * @return order
      */
     public static <X extends Comparable<? super X>> int compareObject(final X pCurr,
                                                                       final X pNew) {
         /* Handle identity */
         if (pCurr == pNew) {
             return 0;
         }
 
         /* Pass the call on, defaulting null to the end of the list */
         return compareObject(pCurr, pNew, true);
     }
 
     /**
      * Compare two similar objects for order.
      *
      * @param <X>       the object type
      * @param pCurr     The current object
      * @param pNew      The new object
      * @param pNullLast is Null at end of list?
      * @return order
      */
     public static <X extends Comparable<? super X>> int compareObject(final X pCurr,
                                                                       final X pNew,
                                                                       final boolean pNullLast) {
         /* Handle identity */
         if (pCurr == pNew) {
             return 0;
         }
 
         /* Handle positioning of nulls */
         if (pCurr == null) {
             return pNullLast
                     ? 1
                     : -1;
         }
         if (pNew == null) {
             return pNullLast
                     ? -1
                     : 1;
         }
 
         /* Both non-Null, so pass the call on */
         return pCurr.compareTo(pNew);
     }
 }