/*
    * 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.commons.collections4.bloomfilter;
  
  import java.util.Arrays;
  import java.util.Objects;
  import java.util.function.IntPredicate;
  import java.util.function.LongPredicate;
  
  /**
   * A bloom filter using an array of bit maps to track enabled bits. This is a standard
   * implementation and should work well for most Bloom filters.
   * @since 4.5
   */
  public final class SimpleBloomFilter implements BloomFilter {
  
      /**
       * The array of bit map longs that defines this Bloom filter. Will be null if the filter is empty.
       */
      private final long[] bitMap;
  
      /**
       * The Shape of this Bloom filter.
       */
      private final Shape shape;
  
      /**
       * The cardinality of this Bloom filter.
       */
      private int cardinality;
  
      /**
       * Creates an empty instance.
       *
       * @param shape The shape for the filter.
       */
      public SimpleBloomFilter(final Shape shape) {
          Objects.requireNonNull(shape, "shape");
          this.shape = shape;
          this.bitMap = new long[BitMap.numberOfBitMaps(shape.getNumberOfBits())];
          this.cardinality = 0;
      }
  
      /**
       * Copy constructor for {@code copy()} use.
       * @param source
       */
      private SimpleBloomFilter(final SimpleBloomFilter source) {
          this.shape = source.shape;
          this.bitMap = source.bitMap.clone();
          this.cardinality = source.cardinality;
      }
  
      @Override
      public long[] asBitMapArray() {
          return Arrays.copyOf(bitMap, bitMap.length);
      }
  
      @Override
      public int cardinality() {
          // Lazy evaluation with caching
          int c = cardinality;
          if (c < 0) {
              cardinality = c = SetOperations.cardinality(this);
          }
          return c;
      }
  
      @Override
      public int characteristics() {
          return 0;
      }
  
      @Override
      public void clear() {
          Arrays.fill(bitMap, 0L);
          cardinality = 0;
      }
  
      @Override
      public boolean contains(final IndexProducer indexProducer) {
          return indexProducer.forEachIndex(idx -> BitMap.contains(bitMap, idx));
      }
  
      @Override
     public SimpleBloomFilter copy() {
         return new SimpleBloomFilter(this);
     }
 
     @Override
     public boolean forEachBitMap(final LongPredicate consumer) {
         Objects.requireNonNull(consumer, "consumer");
         for (final long l : bitMap) {
             if (!consumer.test(l)) {
                 return false;
             }
         }
         return true;
     }
 
     @Override
     public boolean forEachBitMapPair(final BitMapProducer other, final LongBiPredicate func) {
         final CountingLongPredicate p = new CountingLongPredicate(bitMap, func);
         return other.forEachBitMap(p) && p.forEachRemaining();
     }
 
     @Override
     public boolean forEachIndex(final IntPredicate consumer) {
         Objects.requireNonNull(consumer, "consumer");
         return IndexProducer.fromBitMapProducer(this).forEachIndex(consumer);
     }
 
     @Override
     public Shape getShape() {
         return shape;
     }
 
     @Override
     public boolean isEmpty() {
         return cardinality == 0 || forEachBitMap(y -> y == 0);
     }
 
     @Override
     public boolean merge(final BitMapProducer bitMapProducer) {
         Objects.requireNonNull(bitMapProducer, "bitMapProducer");
         try {
             final int[] idx = new int[1];
             bitMapProducer.forEachBitMap(value -> {
                 bitMap[idx[0]++] |= value;
                 return true;
             });
             // idx[0] will be limit+1 so decrement it
             idx[0]--;
             final int idxLimit = BitMap.getLongIndex(shape.getNumberOfBits());
             if (idxLimit == idx[0]) {
                 final long excess = bitMap[idxLimit] >> shape.getNumberOfBits();
                 if (excess != 0) {
                     throw new IllegalArgumentException(
                             String.format("BitMapProducer set a bit higher than the limit for the shape: %s",
                                     shape.getNumberOfBits()));
                 }
             }
             cardinality = -1;
         } catch (final IndexOutOfBoundsException e) {
             throw new IllegalArgumentException(
                     String.format("BitMapProducer should send at most %s maps", bitMap.length), e);
         }
         return true;
     }
 
     @Override
     public boolean merge(final BloomFilter other) {
         Objects.requireNonNull(other, "other");
         if ((other.characteristics() & SPARSE) != 0) {
             merge((IndexProducer) other);
         } else {
             merge((BitMapProducer) other);
         }
         return true;
     }
 
     @Override
     public boolean merge(final Hasher hasher) {
         Objects.requireNonNull(hasher, "hasher");
         return merge(hasher.indices(shape));
     }
 
     @Override
     public boolean merge(final IndexProducer indexProducer) {
         Objects.requireNonNull(indexProducer, "indexProducer");
         indexProducer.forEachIndex(idx -> {
             if (idx < 0 || idx >= shape.getNumberOfBits()) {
                 throw new IllegalArgumentException(String.format(
                         "IndexProducer should only send values in the range[0,%s)", shape.getNumberOfBits()));
             }
             BitMap.set(bitMap, idx);
             return true;
         });
         cardinality = -1;
         return true;
     }
 }