/*
    *    Copyright 2009-2021 the original author or authors.
    *
    *    Licensed 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.ibatis.executor.loader;
  
  import java.io.ByteArrayInputStream;
  import java.io.ByteArrayOutputStream;
  import java.io.Externalizable;
  import java.io.IOException;
  import java.io.InvalidClassException;
  import java.io.ObjectInput;
  import java.io.ObjectInputStream;
  import java.io.ObjectOutput;
  import java.io.ObjectOutputStream;
  import java.io.ObjectStreamException;
  import java.io.StreamCorruptedException;
  import java.util.Arrays;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  import org.apache.ibatis.io.SerialFilterChecker;
  import org.apache.ibatis.reflection.factory.ObjectFactory;
  
  /**
   * @author Eduardo Macarron
   * @author Franta Mejta
   */
  public abstract class AbstractSerialStateHolder implements Externalizable {
  
    private static final long serialVersionUID = 8940388717901644661L;
    private static final ThreadLocal<ObjectOutputStream> stream = new ThreadLocal<>();
    private byte[] userBeanBytes = new byte[0];
    private Object userBean;
    private Map<String, ResultLoaderMap.LoadPair> unloadedProperties;
    private ObjectFactory objectFactory;
    private Class<?>[] constructorArgTypes;
    private Object[] constructorArgs;
  
    public AbstractSerialStateHolder() {
    }
  
    public AbstractSerialStateHolder(
            final Object userBean,
            final Map<String, ResultLoaderMap.LoadPair> unloadedProperties,
            final ObjectFactory objectFactory,
            List<Class<?>> constructorArgTypes,
            List<Object> constructorArgs) {
      this.userBean = userBean;
      this.unloadedProperties = new HashMap<>(unloadedProperties);
      this.objectFactory = objectFactory;
      this.constructorArgTypes = constructorArgTypes.toArray(new Class<?>[0]);
      this.constructorArgs = constructorArgs.toArray(new Object[0]);
    }
  
    @Override
    public final void writeExternal(final ObjectOutput out) throws IOException {
      boolean firstRound = false;
      final ByteArrayOutputStream baos = new ByteArrayOutputStream();
      ObjectOutputStream os = stream.get();
      if (os == null) {
        os = new ObjectOutputStream(baos);
        firstRound = true;
        stream.set(os);
      }
  
      os.writeObject(this.userBean);
      os.writeObject(this.unloadedProperties);
      os.writeObject(this.objectFactory);
      os.writeObject(this.constructorArgTypes);
      os.writeObject(this.constructorArgs);
  
      final byte[] bytes = baos.toByteArray();
      out.writeObject(bytes);
  
      if (firstRound) {
        stream.remove();
      }
    }
  
    @Override
    public final void readExternal(final ObjectInput in) throws IOException, ClassNotFoundException {
      final Object data = in.readObject();
      if (data.getClass().isArray()) {
        this.userBeanBytes = (byte[]) data;
      } else {
        this.userBean = data;
     }
   }
 
   @SuppressWarnings("unchecked")
   protected final Object readResolve() throws ObjectStreamException {
     /* Second run */
     if (this.userBean != null && this.userBeanBytes.length == 0) {
       return this.userBean;
     }
 
     SerialFilterChecker.check();
 
     /* First run */
     try (ObjectInputStream in = new ObjectInputStream(new ByteArrayInputStream(this.userBeanBytes))) {
       this.userBean = in.readObject();
       this.unloadedProperties = (Map<String, ResultLoaderMap.LoadPair>) in.readObject();
       this.objectFactory = (ObjectFactory) in.readObject();
       this.constructorArgTypes = (Class<?>[]) in.readObject();
       this.constructorArgs = (Object[]) in.readObject();
     } catch (final IOException ex) {
       throw (ObjectStreamException) new StreamCorruptedException().initCause(ex);
     } catch (final ClassNotFoundException ex) {
       throw (ObjectStreamException) new InvalidClassException(ex.getLocalizedMessage()).initCause(ex);
     }
 
     final Map<String, ResultLoaderMap.LoadPair> arrayProps = new HashMap<>(this.unloadedProperties);
     final List<Class<?>> arrayTypes = Arrays.asList(this.constructorArgTypes);
     final List<Object> arrayValues = Arrays.asList(this.constructorArgs);
 
     return this.createDeserializationProxy(userBean, arrayProps, objectFactory, arrayTypes, arrayValues);
   }
 
   protected abstract Object createDeserializationProxy(Object target, Map<String, ResultLoaderMap.LoadPair> unloadedProperties, ObjectFactory objectFactory,
           List<Class<?>> constructorArgTypes, List<Object> constructorArgs);
 }