/*
    * 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.proxy2.stub;
  
  import java.util.Collections;
  import java.util.HashSet;
  import java.util.Set;
  
  import org.apache.commons.lang3.ArrayUtils;
  import org.apache.commons.lang3.Validate;
  import org.apache.commons.lang3.builder.Builder;
  import org.apache.commons.proxy2.Invoker;
  import org.apache.commons.proxy2.ObjectProvider;
  import org.apache.commons.proxy2.ProxyFactory;
  import org.apache.commons.proxy2.interceptor.SwitchInterceptor;
  import org.apache.commons.proxy2.invoker.NullInvoker;
  import org.apache.commons.proxy2.provider.ConstantProvider;
  
  public class StubBuilder<T> implements Builder<T>
  {
      //******************************************************************************************************************
      // Fields
      //******************************************************************************************************************
  
      private final ProxyFactory proxyFactory;
      private final T target;
      private final SwitchInterceptor switchInterceptor = new SwitchInterceptor();
      private final Set<Class<?>> proxyTypes = new HashSet<Class<?>>();
  
      //******************************************************************************************************************
      // Constructors
      //******************************************************************************************************************
  
      public StubBuilder(ProxyFactory proxyFactory, Class<T> type)
      {
          this(proxyFactory, type, NullInvoker.INSTANCE);
      }
  
      public StubBuilder(ProxyFactory proxyFactory, Class<T> type, Invoker invoker)
      {
          this.proxyFactory = proxyFactory;
          this.target = proxyFactory.createInvokerProxy(invoker, type);
          this.proxyTypes.add(Validate.notNull(type));
      }
  
      public StubBuilder(ProxyFactory proxyFactory, Class<T> type, ObjectProvider<? extends T> provider)
      {
          this.proxyFactory = proxyFactory;
          this.target = proxyFactory.createDelegatorProxy(provider, type);
          this.proxyTypes.add(Validate.notNull(type));
      }
  
      public StubBuilder(ProxyFactory proxyFactory, Class<T> type, T target)
      {
          this.proxyFactory = proxyFactory;
          this.target = proxyFactory.createDelegatorProxy(new ConstantProvider<T>(target), type);
          this.proxyTypes.add(Validate.notNull(type));
      }
  
      //******************************************************************************************************************
      // Other Methods
      //******************************************************************************************************************
  
      @Override
      public T build()
      {
          return proxyFactory.createInterceptorProxy(target, switchInterceptor,
                  proxyTypes.toArray(ArrayUtils.EMPTY_CLASS_ARRAY));
      }
  
      public <O> StubBuilder<T> train(BaseTrainer<?, O> trainer)
      {
          final TrainingContext trainingContext = TrainingContext.join(proxyFactory);
          try
          {
              final O trainee = trainingContext.push(trainer.traineeType, switchInterceptor);
              trainer.train(trainee);
              proxyTypes.add(trainer.traineeType);
          }
          finally
          {
              trainingContext.part();
          }
          return this;
     }
 
     public StubBuilder<T> addProxyTypes(Class<?>... proxyTypes)
     {
         Collections.addAll(this.proxyTypes, Validate.noNullElements(proxyTypes));
         return this;
     }
 }