package org.apache.samoa.topology.impl;

/*
 * #%L
 * SAMOA
 * %%
 * Copyright (C) 2014 - 2015 Apache Software Foundation
 * %%
 * 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.
 * #L%
 */

import java.nio.ByteBuffer;

import org.apache.s4.base.SerializerDeserializer;
import org.apache.samoa.learners.classifiers.trees.AttributeContentEvent;
import org.apache.samoa.learners.classifiers.trees.ComputeContentEvent;

import com.esotericsoftware.kryo.Kryo;
import com.esotericsoftware.kryo.io.Input;
import com.esotericsoftware.kryo.io.Output;
import com.google.inject.Inject;
import com.google.inject.assistedinject.Assisted;

public class SamoaSerializer implements SerializerDeserializer {

  private ThreadLocal<Kryo> kryoThreadLocal;
  private ThreadLocal<Output> outputThreadLocal;

  private int initialBufferSize = 2048;
  private int maxBufferSize = 256 * 1024;

  public void setMaxBufferSize(int maxBufferSize) {
    this.maxBufferSize = maxBufferSize;
  }

  /**
   * 
   * @param classLoader
   *          classloader able to handle classes to serialize/deserialize. For instance, application-level events can
   *          only be handled by the application classloader.
   */
  @Inject
  public SamoaSerializer(@Assisted final ClassLoader classLoader) {
    kryoThreadLocal = new ThreadLocal<Kryo>() {

      @Override
      protected Kryo initialValue() {
        Kryo kryo = new Kryo();
        kryo.setClassLoader(classLoader);
        kryo.register(AttributeContentEvent.class, new AttributeContentEvent.AttributeCEFullPrecSerializer());
        kryo.register(ComputeContentEvent.class, new ComputeContentEvent.ComputeCEFullPrecSerializer());
        kryo.setRegistrationRequired(false);
        return kryo;
      }
    };

    outputThreadLocal = new ThreadLocal<Output>() {
      @Override
      protected Output initialValue() {
        Output output = new Output(initialBufferSize, maxBufferSize);
        return output;
      }
    };

  }

  @Override
  public Object deserialize(ByteBuffer rawMessage) {
    Input input = new Input(rawMessage.array());
    try {
      return kryoThreadLocal.get().readClassAndObject(input);
    } finally {
      input.close();
    }
  }

  @SuppressWarnings("resource")
  @Override
  public ByteBuffer serialize(Object message) {
    Output output = outputThreadLocal.get();
    try {
      kryoThreadLocal.get().writeClassAndObject(output, message);
      return ByteBuffer.wrap(output.toBytes());
    } finally {
      output.clear();
    }
  }
}