/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You 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
    *
    *      https://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 org.apache.commons.lang3;
  
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.EnumSet;
  import java.util.List;
  import java.util.Map;
  import java.util.Objects;
  import java.util.function.Function;
  import java.util.function.ToIntFunction;
  import java.util.stream.Collectors;
  import java.util.stream.Stream;
  
  import org.apache.commons.lang3.stream.Streams;
  
  /**
   * Provides methods for Java enums.
   *
   * <p>#ThreadSafe#</p>
   *
   * @since 3.0
   */
  public class EnumUtils {
  
      private static final String CANNOT_STORE_S_S_VALUES_IN_S_BITS = "Cannot store %s %s values in %s bits";
      private static final String ENUM_CLASS_MUST_BE_DEFINED = "EnumClass must be defined.";
      private static final String NULL_ELEMENTS_NOT_PERMITTED = "null elements not permitted";
      private static final String S_DOES_NOT_SEEM_TO_BE_AN_ENUM_TYPE = "%s does not seem to be an Enum type";
  
      /**
       * Validate {@code enumClass}.
       *
       * @param <E> the type of the enumeration.
       * @param enumClass to check.
       * @return {@code enumClass}.
       * @throws NullPointerException if {@code enumClass} is {@code null}.
       * @throws IllegalArgumentException if {@code enumClass} is not an enum class.
       * @since 3.2
       */
      private static <E extends Enum<E>> Class<E> asEnum(final Class<E> enumClass) {
          Objects.requireNonNull(enumClass, ENUM_CLASS_MUST_BE_DEFINED);
          Validate.isTrue(enumClass.isEnum(), S_DOES_NOT_SEEM_TO_BE_AN_ENUM_TYPE, enumClass);
          return enumClass;
      }
  
      /**
       * Validate that {@code enumClass} is compatible with representation in a {@code long}.
       *
       * @param <E> the type of the enumeration.
       * @param enumClass to check.
       * @return {@code enumClass}.
       * @throws NullPointerException if {@code enumClass} is {@code null}.
       * @throws IllegalArgumentException if {@code enumClass} is not an enum class or has more than 64 values.
       * @since 3.0.1
       */
      private static <E extends Enum<E>> Class<E> checkBitVectorable(final Class<E> enumClass) {
          final E[] constants = asEnum(enumClass).getEnumConstants();
          Validate.isTrue(constants.length <= Long.SIZE, CANNOT_STORE_S_S_VALUES_IN_S_BITS, Integer.valueOf(constants.length), enumClass.getSimpleName(),
                  Integer.valueOf(Long.SIZE));
          return enumClass;
      }
  
      /**
       * Creates a long bit vector representation of the given array of Enum values.
       *
       * <p>This generates a value that is usable by {@link EnumUtils#processBitVector}.</p>
       *
       * <p>Do not use this method if you have more than 64 values in your Enum, as this
       * would create a value greater than a long can hold.</p>
       *
       * @param enumClass the class of the enum we are working with, not {@code null}.
       * @param values    the values we want to convert, not {@code null}.
       * @param <E>       the type of the enumeration.
       * @return a long whose value provides a binary representation of the given set of enum values.
       * @throws NullPointerException if {@code enumClass} or {@code values} is {@code null}.
       * @throws IllegalArgumentException if {@code enumClass} is not an enum class or has more than 64 values.
       * @since 3.0.1
       * @see #generateBitVectors(Class, Iterable)
       */
      @SafeVarargs
      public static <E extends Enum<E>> long generateBitVector(final Class<E> enumClass, final E... values) {
          Validate.noNullElements(values);
         return generateBitVector(enumClass, Arrays.asList(values));
     }
 
     /**
      * Creates a long bit vector representation of the given subset of an Enum.
      *
      * <p>This generates a value that is usable by {@link EnumUtils#processBitVector}.</p>
      *
      * <p>Do not use this method if you have more than 64 values in your Enum, as this
      * would create a value greater than a long can hold.</p>
      *
      * @param enumClass the class of the enum we are working with, not {@code null}.
      * @param values    the values we want to convert, not {@code null}, neither containing {@code null}.
      * @param <E>       the type of the enumeration.
      * @return a long whose value provides a binary representation of the given set of enum values.
      * @throws NullPointerException if {@code enumClass} or {@code values} is {@code null}.
      * @throws IllegalArgumentException if {@code enumClass} is not an enum class or has more than 64 values,
      *                                  or if any {@code values} {@code null}.
      * @since 3.0.1
      * @see #generateBitVectors(Class, Iterable)
      */
     public static <E extends Enum<E>> long generateBitVector(final Class<E> enumClass, final Iterable<? extends E> values) {
         checkBitVectorable(enumClass);
         Objects.requireNonNull(values, "values");
         long total = 0;
         for (final E constant : values) {
             Objects.requireNonNull(constant, NULL_ELEMENTS_NOT_PERMITTED);
             total |= 1L << constant.ordinal();
         }
         return total;
     }
 
     /**
      * Creates a bit vector representation of the given subset of an Enum using as many {@code long}s as needed.
      *
      * <p>This generates a value that is usable by {@link EnumUtils#processBitVectors}.</p>
      *
      * <p>Use this method if you have more than 64 values in your Enum.</p>
      *
      * @param enumClass the class of the enum we are working with, not {@code null}.
      * @param values    the values we want to convert, not {@code null}, neither containing {@code null}.
      * @param <E>       the type of the enumeration.
      * @return a long[] whose values provide a binary representation of the given set of enum values
      *         with the least significant digits rightmost.
      * @throws NullPointerException if {@code enumClass} or {@code values} is {@code null}.
      * @throws IllegalArgumentException if {@code enumClass} is not an enum class, or if any {@code values} {@code null}.
      * @since 3.2
      */
     @SafeVarargs
     public static <E extends Enum<E>> long[] generateBitVectors(final Class<E> enumClass, final E... values) {
         asEnum(enumClass);
         Validate.noNullElements(values);
         final EnumSet<E> condensed = EnumSet.noneOf(enumClass);
         Collections.addAll(condensed, values);
         final long[] result = new long[(enumClass.getEnumConstants().length - 1) / Long.SIZE + 1];
         for (final E value : condensed) {
             result[value.ordinal() / Long.SIZE] |= 1L << value.ordinal() % Long.SIZE;
         }
         ArrayUtils.reverse(result);
         return result;
     }
 
     /**
      * Creates a bit vector representation of the given subset of an Enum using as many {@code long}s as needed.
      *
      * <p>This generates a value that is usable by {@link EnumUtils#processBitVectors}.</p>
      *
      * <p>Use this method if you have more than 64 values in your Enum.</p>
      *
      * @param enumClass the class of the enum we are working with, not {@code null}.
      * @param values    the values we want to convert, not {@code null}, neither containing {@code null}.
      * @param <E>       the type of the enumeration.
      * @return a long[] whose values provide a binary representation of the given set of enum values
      *         with the least significant digits rightmost.
      * @throws NullPointerException if {@code enumClass} or {@code values} is {@code null}.
      * @throws IllegalArgumentException if {@code enumClass} is not an enum class, or if any {@code values} {@code null}.
      * @since 3.2
      */
     public static <E extends Enum<E>> long[] generateBitVectors(final Class<E> enumClass, final Iterable<? extends E> values) {
         asEnum(enumClass);
         Objects.requireNonNull(values, "values");
         final EnumSet<E> condensed = EnumSet.noneOf(enumClass);
         values.forEach(constant -> condensed.add(Objects.requireNonNull(constant, NULL_ELEMENTS_NOT_PERMITTED)));
         final long[] result = new long[(enumClass.getEnumConstants().length - 1) / Long.SIZE + 1];
         for (final E value : condensed) {
             result[value.ordinal() / Long.SIZE] |= 1L << value.ordinal() % Long.SIZE;
         }
         ArrayUtils.reverse(result);
         return result;
     }
 
     /**
      * Gets the enum for the class, returning {@code null} if not found.
      *
      * <p>This method differs from {@link Enum#valueOf} in that it does not throw an exception
      * for an invalid enum name.</p>
      *
      * @param <E> the type of the enumeration.
      * @param enumClass  the class of the enum to query, not null.
      * @param enumName   the enum name, null returns null.
      * @return the enum, null if not found.
      */
     public static <E extends Enum<E>> E getEnum(final Class<E> enumClass, final String enumName) {
         return getEnum(enumClass, enumName, null);
     }
 
     /**
      * Gets the enum for the class, returning {@code defaultEnum} if not found.
      *
      * <p>This method differs from {@link Enum#valueOf} in that it does not throw an exception
      * for an invalid enum name.</p>
      *
      * @param <E> the type of the enumeration.
      * @param enumClass   the class of the enum to query, null returns default enum.
      * @param enumName    the enum name, null returns default enum.
      * @param defaultEnum the default enum.
      * @return the enum, default enum if not found.
      * @since 3.10
      */
     public static <E extends Enum<E>> E getEnum(final Class<E> enumClass, final String enumName, final E defaultEnum) {
         if (enumClass == null || enumName == null) {
             return defaultEnum;
         }
         try {
             return Enum.valueOf(enumClass, enumName);
         } catch (final IllegalArgumentException e) {
             return defaultEnum;
         }
     }
 
     /**
      * Gets the enum for the class, returning {@code null} if not found.
      *
      * <p>This method differs from {@link Enum#valueOf} in that it does not throw an exception
      * for an invalid enum name and performs case insensitive matching of the name.</p>
      *
      * @param <E>         the type of the enumeration.
      * @param enumClass   the class of the enum to query, may be null.
      * @param enumName    the enum name, null returns null.
      * @return the enum, null if not found.
      * @since 3.8
      */
     public static <E extends Enum<E>> E getEnumIgnoreCase(final Class<E> enumClass, final String enumName) {
         return getEnumIgnoreCase(enumClass, enumName, null);
     }
 
     /**
      * Gets the enum for the class, returning {@code defaultEnum} if not found.
      *
      * <p>This method differs from {@link Enum#valueOf} in that it does not throw an exception
      * for an invalid enum name and performs case insensitive matching of the name.</p>
      *
      * @param <E>         the type of the enumeration.
      * @param enumClass   the class of the enum to query, null returns default enum.
      * @param enumName    the enum name, null returns default enum.
      * @param defaultEnum the default enum.
      * @return the enum, default enum if not found.
      * @since 3.10
      */
     public static <E extends Enum<E>> E getEnumIgnoreCase(final Class<E> enumClass, final String enumName,
         final E defaultEnum) {
         return getFirstEnumIgnoreCase(enumClass, enumName, Enum::name, defaultEnum);
     }
 
     /**
      * Gets the {@link List} of enums.
      *
      * <p>This method is useful when you need a list of enums rather than an array.</p>
      *
      * @param <E> the type of the enumeration.
      * @param enumClass  the class of the enum to query, not null.
      * @return the modifiable list of enums, never null.
      */
     public static <E extends Enum<E>> List<E> getEnumList(final Class<E> enumClass) {
         return new ArrayList<>(Arrays.asList(enumClass.getEnumConstants()));
     }
 
     /**
      * Gets the {@link Map} of enums by name.
      *
      * <p>This method is useful when you need a map of enums by name.</p>
      *
      * @param <E> the type of the enumeration.
      * @param enumClass  the class of the enum to query, not null.
      * @return the modifiable map of enum names to enums, never null.
      */
     public static <E extends Enum<E>> Map<String, E> getEnumMap(final Class<E> enumClass) {
         return getEnumMap(enumClass, E::name);
     }
 
     /**
      * Gets the {@link Map} of enums by name.
      *
      * <p>
      * This method is useful when you need a map of enums by name.
      * </p>
      *
      * @param <E>         the type of enumeration.
      * @param <K>         the type of the map key.
      * @param enumClass   the class of the enum to query, not null.
      * @param keyFunction the function to query for the key, not null.
      * @return the modifiable map of enums, never null.
      * @since 3.13.0
      */
     public static <E extends Enum<E>, K> Map<K, E> getEnumMap(final Class<E> enumClass, final Function<E, K> keyFunction) {
         return stream(enumClass).collect(Collectors.toMap(keyFunction::apply, Function.identity()));
     }
 
     /**
      * Gets the enum for the class in a system property, returning {@code defaultEnum} if not found.
      *
      * <p>
      * This method differs from {@link Enum#valueOf} in that it does not throw an exception for an invalid enum name.
      * </p>
      * <p>
      * If a {@link SecurityException} is caught, the return value is {@code null}.
      * </p>
      *
      * @param <E>         the type of the enumeration.
      * @param enumClass   the class of the enum to query, not null.
      * @param propName    the system property key for the enum name, null returns default enum.
      * @param defaultEnum the default enum.
      * @return the enum, default enum if not found.
      * @since 3.13.0
      */
     public static <E extends Enum<E>> E getEnumSystemProperty(final Class<E> enumClass, final String propName, final E defaultEnum) {
         return getEnum(enumClass, SystemProperties.getProperty(propName), defaultEnum);
     }
 
     /**
      * Gets the enum for the class and value, returning {@code defaultEnum} if not found.
      *
      * <p>
      * This method differs from {@link Enum#valueOf} in that it does not throw an exception for an invalid enum name and performs case insensitive matching of
      * the name.
      * </p>
      *
      * @param <E>           the type of the enumeration.
      * @param enumClass     the class of the enum to query, not null.
      * @param value         the enum name, null returns default enum.
      * @param toIntFunction the function that gets an int for an enum for comparison to {@code value}.
      * @param defaultEnum   the default enum.
      * @return an enum, default enum if not found.
      * @since 3.18.0
      */
     public static <E extends Enum<E>> E getFirstEnum(final Class<E> enumClass, final int value, final ToIntFunction<E> toIntFunction, final E defaultEnum) {
         if (isEnum(enumClass)) {
             return defaultEnum;
         }
         return stream(enumClass).filter(e -> value == toIntFunction.applyAsInt(e)).findFirst().orElse(defaultEnum);
     }
 
     /**
      * Gets the enum for the class, returning {@code defaultEnum} if not found.
      *
      * <p>This method differs from {@link Enum#valueOf} in that it does not throw an exception
      * for an invalid enum name and performs case insensitive matching of the name.</p>
      *
      * @param <E>         the type of the enumeration.
      * @param enumClass   the class of the enum to query, null returns default enum.
      * @param enumName    the enum name, null returns default enum.
      * @param stringFunction the function that gets the string for an enum for comparison to {@code enumName}.
      * @param defaultEnum the default enum.
      * @return an enum, default enum if not found.
      * @since 3.13.0
      */
     public static <E extends Enum<E>> E getFirstEnumIgnoreCase(final Class<E> enumClass, final String enumName, final Function<E, String> stringFunction,
             final E defaultEnum) {
         if (enumName == null) {
             return defaultEnum;
         }
         return stream(enumClass).filter(e -> enumName.equalsIgnoreCase(stringFunction.apply(e))).findFirst().orElse(defaultEnum);
     }
 
     private static <E extends Enum<E>> boolean isEnum(final Class<E> enumClass) {
         return enumClass != null && !enumClass.isEnum();
     }
 
     /**
      * Checks if the specified name is a valid enum for the class.
      *
      * <p>
      * This method differs from {@link Enum#valueOf} in that it checks if the name is a valid enum without needing to catch the exception.
      * </p>
      *
      * @param <E>       the type of the enumeration.
      * @param enumClass the class of the enum to query, null returns false.
      * @param enumName  the enum name, null returns false.
      * @return true if the enum name is valid, otherwise false.
      */
     public static <E extends Enum<E>> boolean isValidEnum(final Class<E> enumClass, final String enumName) {
         return getEnum(enumClass, enumName) != null;
     }
 
     /**
      * Checks if the specified name is a valid enum for the class.
      *
      * <p>
      * This method differs from {@link Enum#valueOf} in that it checks if the name is a valid enum without needing to catch the exception and performs case
      * insensitive matching of the name.
      * </p>
      *
      * @param <E>       the type of the enumeration.
      * @param enumClass the class of the enum to query, null returns false.
      * @param enumName  the enum name, null returns false.
      * @return true if the enum name is valid, otherwise false.
      * @since 3.8
      */
     public static <E extends Enum<E>> boolean isValidEnumIgnoreCase(final Class<E> enumClass, final String enumName) {
         return getEnumIgnoreCase(enumClass, enumName) != null;
     }
 
     /**
      * Convert a long value created by {@link EnumUtils#generateBitVector} into the set of
      * enum values that it represents.
      *
      * <p>If you store this value, beware any changes to the enum that would affect ordinal values.</p>
      *
      * @param enumClass the class of the enum we are working with, not {@code null}.
      * @param value     the long value representation of a set of enum values.
      * @param <E>       the type of the enumeration.
      * @return a set of enum values.
      * @throws NullPointerException if {@code enumClass} is {@code null}.
      * @throws IllegalArgumentException if {@code enumClass} is not an enum class or has more than 64 values.
      * @since 3.0.1
      */
     public static <E extends Enum<E>> EnumSet<E> processBitVector(final Class<E> enumClass, final long value) {
         return processBitVectors(checkBitVectorable(enumClass), value);
     }
 
     /**
      * Convert a {@code long[]} created by {@link EnumUtils#generateBitVectors} into the set of
      * enum values that it represents.
      *
      * <p>If you store this value, beware any changes to the enum that would affect ordinal values.</p>
      *
      * @param enumClass the class of the enum we are working with, not {@code null}.
      * @param values     the long[] bearing the representation of a set of enum values, the least significant digits rightmost, not {@code null}.
      * @param <E>       the type of the enumeration.
      * @return a set of enum values.
      * @throws NullPointerException if {@code enumClass} is {@code null}.
      * @throws IllegalArgumentException if {@code enumClass} is not an enum class.
      * @since 3.2
      */
     public static <E extends Enum<E>> EnumSet<E> processBitVectors(final Class<E> enumClass, final long... values) {
         final EnumSet<E> results = EnumSet.noneOf(asEnum(enumClass));
         final long[] lvalues = ArrayUtils.clone(Objects.requireNonNull(values, "values"));
         ArrayUtils.reverse(lvalues);
         stream(enumClass).forEach(constant -> {
             final int block = constant.ordinal() / Long.SIZE;
             if (block < lvalues.length && (lvalues[block] & 1L << constant.ordinal() % Long.SIZE) != 0) {
                 results.add(constant);
             }
         });
         return results;
     }
 
     /**
      * Returns a sequential ordered stream whose elements are the given class' enum values.
      *
      * @param <T>   the type of stream elements.
      * @param clazz the class containing the enum values, may be null.
      * @return the new stream, empty of {@code clazz} is null.
      * @since 3.18.0
      * @see Class#getEnumConstants()
      */
     public static <T> Stream<T> stream(final Class<T> clazz) {
         return clazz != null ? Streams.of(clazz.getEnumConstants()) : Stream.empty();
     }
 
     /**
      * This constructor is public to permit tools that require a JavaBean
      * instance to operate.
      *
      * @deprecated TODO Make private in 4.0.
      */
     @Deprecated
     public EnumUtils() {
         // empty
     }
 }