content: /*
   *  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
   *
   *        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 org.apache.causeway.testing.fakedata.applib.services;
  
  import java.util.Collection;
  import java.util.List;
  import java.util.concurrent.Callable;
  import java.util.function.Predicate;
  
  import org.apache.causeway.applib.annotation.Programmatic;
  
  /**
   * Returns random instance of a provided collection, with overloads allowing instances to be excluded according to a
   * {@link Predicate}.
   *
   * @since 2.0 {@index}
   */
  public class Collections extends AbstractRandomValueGenerator {
  
      public Collections(final FakeDataService fakeDataService) {
          super(fakeDataService);
      }
  
      public <E extends Enum<E>> E anyEnum(final Class<E> enumType) {
          final E[] enumConstants = enumType.getEnumConstants();
          return enumConstants[fake.ints().upTo(enumConstants.length)];
      }
  
      public <E extends Enum<E>> E anyEnumExcept(final Class<E> enumType, final Predicate<E> except) {
          return find(() -> anyEnum(enumType), except);
      }
  
      public <T> T anyBounded(final Class<T> cls) {
          final List<T> list = fake.repositoryService.allInstances(cls);
          return anyOf(list);
      }
  
      public <T> T anyBoundedExcept(final Class<T> cls, final Predicate<T> except) {
          final List<T> list = fake.repositoryService.allInstances(cls);
          return anyOfExcept(list, except);
      }
  
      public <T> T anyOf(final List<T> list) {
          final int randomIdx = fake.ints().upTo(list.size());
          return list.get(randomIdx);
      }
  
      public <T> T anyOf(final Collection<T> collection) {
          final int randomIdx = fake.ints().upTo(collection.size());
          int i = 0;
          for (T element : collection) {
              if (randomIdx == i++) {
                  return element;
              }
          }
          throw new RuntimeException(
                  "failed to obtain random element from collection - most likely a bug in the FakeData service itself");
      }
  
      public <T> T anyOfExcept(final List<T> list, final Predicate<T> except) {
          return find(() -> anyOf(list), except);
      }
  
      public <T> T anyOfExcept(final Collection<T> collection, final Predicate<T> except) {
          return find(() -> anyOf(collection), except);
      }
  
      public char anyOf(final char... elements) {
          final int randomIdx = fake.ints().upTo(elements.length);
          return elements[randomIdx];
      }
  
      public char anyOfExcept(final char[] elements, final Predicate<Character> except) {
          return find(() -> anyOf(elements), except);
      }
  
      public byte anyOf(final byte... elements) {
          final int randomIdx = fake.ints().upTo(elements.length);
          return elements[randomIdx];
      }
  
      public byte anyOfExcept(final byte[] elements, final Predicate<Byte> except) {
          return find(() -> anyOf(elements), except);
      }
  
      public short anyOf(final short... elements) {
          final int randomIdx = fake.ints().upTo(elements.length);
          return elements[randomIdx];
      }
  
      public short anyOfExcept(final short[] elements, final Predicate<Short> except) {
          return find(() -> anyOf(elements), except);
      }
  
      public int anyOf(final int... elements) {
          final int randomIdx = fake.ints().upTo(elements.length);
          return elements[randomIdx];
      }
  
      public int anyOfExcept(final int[] elements, final Predicate<Integer> except) {
          return find(() -> anyOf(elements), except);
      }
  
      public long anyOf(final long... elements) {
          final int randomIdx = fake.ints().upTo(elements.length);
          return elements[randomIdx];
      }
  
      @Programmatic
      public long anyOfExcept(final long[] elements, final Predicate<Long> except) {
          return find(() -> anyOf(elements), except);
      }
  
      public float anyOf(final float... elements) {
          final int randomIdx = fake.ints().upTo(elements.length);
          return elements[randomIdx];
      }
  
      public float anyOfExcept(final float[] elements, final Predicate<Float> except) {
          return find(() -> anyOf(elements), except);
      }
  
      public double anyOf(final double... elements) {
          final int randomIdx = fake.ints().upTo(elements.length);
          return elements[randomIdx];
      }
  
      public double anyOfExcept(final double[] elements, final Predicate<Double> except) {
          return find(() -> anyOf(elements), except);
      }
  
      public boolean anyOf(final boolean... elements) {
          final int randomIdx = fake.ints().upTo(elements.length);
          return elements[randomIdx];
      }
  
      public boolean anyOfExcept(final boolean[] elements, final Predicate<Boolean> except) {
          return find(() -> anyOf(elements), except);
      }
  
      public <T> T anyOf(@SuppressWarnings("unchecked") final T... elements) {
          final int randomIdx = fake.ints().upTo(elements.length);
          return elements[randomIdx];
      }
  
      public <T> T anyOfExcept(final T[] elements, final Predicate<T> except) {
          return find(() -> anyOf(elements), except);
      }
  
      static <E> E find(final Callable<E> block, final Predicate<E> except) {
          for(int i=0; i<100; i++) {
              final E e;
              try {
                  e = block.call();
              } catch (Exception e1) {
                  throw new RuntimeException("Problem finding candidate values");
              }
              if(!except.test(e)) {
                  return e;
              }
          }
          throw new RuntimeException("Failed to find a random element in collection");
      }
  
  }
  