/*
    * 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.maven.model;
  
  import java.util.AbstractList;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Objects;
  import java.util.function.Consumer;
  import java.util.function.Function;
  import java.util.function.Supplier;
  
  class WrapperList<T, U> extends AbstractList<T> {
      private final Supplier<List<U>> getter;
      private final Consumer<List<U>> setter;
      private final Function<U, T> mapper;
      private final Function<T, U> revMapper;
  
      WrapperList(List<U> list, Function<U, T> mapper, Function<T, U> revMapper) {
          this(() -> list, null, mapper, revMapper);
      }
  
      WrapperList(Supplier<List<U>> getter, Consumer<List<U>> setter, Function<U, T> mapper, Function<T, U> revMapper) {
          this.getter = getter;
          this.setter = setter;
          this.mapper = mapper;
          this.revMapper = revMapper;
      }
  
      @Override
      public T get(int index) {
          return mapper.apply(getter.get().get(index));
      }
  
      @Override
      public int size() {
          return getter.get().size();
      }
  
      @Override
      public boolean add(T t) {
          Objects.requireNonNull(t);
          if (setter != null) {
              List<U> list = new ArrayList<>(getter.get());
              boolean ret = list.add(revMapper.apply(t));
              setter.accept(list);
              return ret;
          } else {
              return getter.get().add(revMapper.apply(t));
          }
      }
  
      @Override
      public T set(int index, T element) {
          Objects.requireNonNull(element);
          if (setter != null) {
              List<U> list = new ArrayList<>(getter.get());
              U ret = list.set(index, revMapper.apply(element));
              setter.accept(list);
              return mapper.apply(ret);
          } else {
              return mapper.apply(getter.get().set(index, revMapper.apply(element)));
          }
      }
  
      @Override
      public void add(int index, T element) {
          Objects.requireNonNull(element);
          if (setter != null) {
              List<U> list = new ArrayList<>(getter.get());
              list.add(index, revMapper.apply(element));
              setter.accept(list);
          } else {
              getter.get().add(index, revMapper.apply(element));
          }
      }
  
      @Override
      public T remove(int index) {
          if (setter != null) {
              List<U> list = new ArrayList<>(getter.get());
              U ret = list.remove(index);
              setter.accept(list);
             return mapper.apply(ret);
         } else {
             return mapper.apply(getter.get().remove(index));
         }
     }
 }