/*
    * 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.properties;
  
  import java.util.AbstractMap.SimpleEntry;
  import java.util.Collections;
  import java.util.Enumeration;
  import java.util.Iterator;
  import java.util.LinkedHashSet;
  import java.util.Map;
  import java.util.Objects;
  import java.util.Properties;
  import java.util.Set;
  import java.util.function.BiConsumer;
  import java.util.function.BiFunction;
  import java.util.function.Function;
  import java.util.stream.Collectors;
  
  /**
   * A drop-in replacement for {@link Properties} for ordered keys.
   * <p>
   * Overrides methods to keep keys in insertion order. Allows other methods in the superclass to work with ordered keys.
   * </p>
   *
   * @see OrderedPropertiesFactory#INSTANCE
   * @since 4.5.0-M1
   */
  public class OrderedProperties extends Properties {
  
      private static final long serialVersionUID = 1L;
  
      /**
       * Preserves the insertion order.
       */
      private final LinkedHashSet<Object> orderedKeys = new LinkedHashSet<>();
  
      /**
       * Constructs a new instance.
       */
      public OrderedProperties() {
          // empty
      }
  
      @Override
      public synchronized void clear() {
          orderedKeys.clear();
          super.clear();
      }
  
      @Override
      public synchronized Object compute(final Object key, final BiFunction<? super Object, ? super Object, ? extends Object> remappingFunction) {
          final Object compute = super.compute(key, remappingFunction);
          if (compute != null) {
              orderedKeys.add(key);
          }
          return compute;
      }
  
      @Override
      public synchronized Object computeIfAbsent(final Object key, final Function<? super Object, ? extends Object> mappingFunction) {
          final Object computeIfAbsent = super.computeIfAbsent(key, mappingFunction);
          if (computeIfAbsent != null) {
              orderedKeys.add(key);
          }
          return computeIfAbsent;
      }
  
      @Override
      public Set<Map.Entry<Object, Object>> entrySet() {
          return orderedKeys.stream().map(k -> new SimpleEntry<>(k, get(k))).collect(Collectors.toCollection(LinkedHashSet::new));
      }
  
      @Override
      public synchronized void forEach(final BiConsumer<? super Object, ? super Object> action) {
          Objects.requireNonNull(action);
          orderedKeys.forEach(k -> action.accept(k, get(k)));
      }
  
      @Override
      public synchronized Enumeration<Object> keys() {
          return Collections.enumeration(orderedKeys);
      }
  
      @Override
      public Set<Object> keySet() {
         return orderedKeys;
     }
 
     @Override
     public synchronized Object merge(final Object key, final Object value,
             final BiFunction<? super Object, ? super Object, ? extends Object> remappingFunction) {
         orderedKeys.add(key);
         return super.merge(key, value, remappingFunction);
     }
 
     @Override
     public Enumeration<?> propertyNames() {
         return Collections.enumeration(orderedKeys);
     }
 
     @Override
     public synchronized Object put(final Object key, final Object value) {
         final Object put = super.put(key, value);
         if (put == null) {
             orderedKeys.add(key);
         }
         return put;
     }
 
     @Override
     public synchronized void putAll(final Map<? extends Object, ? extends Object> t) {
         orderedKeys.addAll(t.keySet());
         super.putAll(t);
     }
 
     @Override
     public synchronized Object putIfAbsent(final Object key, final Object value) {
         final Object putIfAbsent = super.putIfAbsent(key, value);
         if (putIfAbsent == null) {
             orderedKeys.add(key);
         }
         return putIfAbsent;
     }
 
     @Override
     public synchronized Object remove(final Object key) {
         final Object remove = super.remove(key);
         if (remove != null) {
             orderedKeys.remove(key);
         }
         return remove;
     }
 
     @Override
     public synchronized boolean remove(final Object key, final Object value) {
         final boolean remove = super.remove(key, value);
         if (remove) {
             orderedKeys.remove(key);
         }
         return remove;
     }
 
     @Override
     public synchronized String toString() {
         // Must override for Java 17 to maintain order since the implementation is based on a map
         final int max = size() - 1;
         if (max == -1) {
             return "{}";
         }
         final StringBuilder sb = new StringBuilder();
         final Iterator<Map.Entry<Object, Object>> it = entrySet().iterator();
         sb.append('{');
         for (int i = 0;; i++) {
             final Map.Entry<Object, Object> e = it.next();
             final Object key = e.getKey();
             final Object value = e.getValue();
             sb.append(key == this ? "(this Map)" : key.toString());
             sb.append('=');
             sb.append(value == this ? "(this Map)" : value.toString());
             if (i == max) {
                 return sb.append('}').toString();
             }
             sb.append(", ");
         }
     }
 }