/*
 * 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.juneau.internal;

import static org.apache.juneau.common.utils.Utils.*;

import java.util.*;
import java.util.function.*;

import org.apache.juneau.*;
import org.apache.juneau.collections.*;

/**
 * Represents a wrapped {@link BeanMap} where property values can be overridden, removed, or reordered without
 * affecting the underlying bean.
 *
 * <p>
 * Provides the {@link #filterKeys(List)} method for specifying the keys to keep in the bean map and in what order
 * they should appear.
 *
 * <h5 class='section'>See Also:</h5><ul>

 * </ul>
 *
 * @param <T> The class type of the wrapped bean.
 */
public class DelegateBeanMap<T> extends BeanMap<T> {

   private Set<String> keys = set();
   private JsonMap overrideValues = new JsonMap();

   /**
    * Constructor.
    *
    * @param bean The bean being wrapped.
    * @param session The bean session that created this bean map.
    */
   @SuppressWarnings("unchecked")
   public
   DelegateBeanMap(T bean, BeanSession session) {
      super(session, bean, session.getBeanMeta((Class<T>)bean.getClass()));
   }

   /**
    * Add a key in the next position.
    *
    * @param key The key to add.
    */
   public void addKey(String key) {
      this.keys.add(key);
   }

   @Override /* Map */
   public Object put(String key, Object val) {
      this.overrideValues.put(key, val);
      this.keys.add(key);
      return null;
   }

   @Override /* Map */
   public Object get(Object key) {
      if (overrideValues.containsKey(key))
         return overrideValues.get(key);
      return super.get(key);
   }

   @Override /* Map */
   public Set<String> keySet() {
      return keys;
   }

   /**
    * Remove all but the specified properties from this bean map.
    *
    * <p>
    * This does not affect the underlying bean.
    *
    * @param keys The remaining keys in the bean map (in the specified order).
    * @return This object.
    */
   public DelegateBeanMap<T> filterKeys(List<String> keys) {
      this.keys.clear();
      this.keys.addAll(keys);
      return this;
   }

   @Override /* Map */
   public Object remove(Object key) {
      keys.remove(key);
      return null;
   }

   @Override /* BeanMap */
   public BeanMeta<T> getMeta() {
      return new BeanMetaFiltered<>(super.getMeta(), keys);
   }

   @Override /* Map */
   public synchronized Set<Entry<String,Object>> entrySet() {
      Set<Entry<String,Object>> s = set();
      keys.forEach(k -> {
         BeanMapEntry bme;
         if (overrideValues.containsKey(k))
            bme = new BeanMapEntryOverride(this, this.getPropertyMeta(k), overrideValues.get(k));
         else
            bme = this.getProperty(k);
         if (bme == null)
            throw new BeanRuntimeException(super.getClassMeta().getInnerClass(), "Property ''{0}'' not found on class.", k);
         s.add(bme);
      });
      return s;
   }

   @Override /* BeanMap */
   public Collection<BeanPropertyMeta> getProperties() {
      List<BeanPropertyMeta> l = new ArrayList<>(keys.size());
      keys.forEach(k -> {
         BeanPropertyMeta p = this.getPropertyMeta(k);
         if (overrideValues.containsKey(k))
            p = BeanPropertyMeta.builder(this.meta, k).overrideValue(overrideValues.get(k)).delegateFor(p).build();
         if (p == null)
            p = BeanPropertyMeta.builder(this.meta, k).overrideValue(null).delegateFor(p).build();
         l.add(p);
      });
      return l;
   }

   @Override
   public BeanMap<T> forEachProperty(Predicate<BeanPropertyMeta> filter, Consumer<BeanPropertyMeta> action) {
      getProperties().forEach(x -> {
         if (filter == null || filter.test(x))
            action.accept(x);
      });
      return this;
   }

   class BeanMapEntryOverride extends BeanMapEntry {
      Object value;

      BeanMapEntryOverride(BeanMap<?> bm, BeanPropertyMeta bpm, Object value) {
         super(bm, bpm, bpm.getName());
         this.value = value;
      }

      @Override /* Map.Entry */
      public Object getValue() {
         return value;
      }
   }
}