/*
 * Copyright Terracotta, Inc.
 *
 * 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.ehcache.clustered.client.internal.service;

import org.ehcache.clustered.common.internal.store.ValueWrapper;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;

/**
 * ValueCodecFactory
 */
class ValueCodecFactory {
  static <T> ValueCodec<T> getCodecForClass(Class<T> clazz) {
    if (!Serializable.class.isAssignableFrom(clazz)) {
      throw new IllegalArgumentException("The provided type is invalid as it is not Serializable " + clazz);
    }
    if (Integer.class.equals(clazz) || Long.class.equals(clazz)
        || Float.class.equals(clazz) || Double.class.equals(clazz)
        || Byte.class.equals(clazz) || Character.class.equals(clazz)
        || clazz.isPrimitive() || String.class.equals(clazz)) {
      return new IdentityCodec<T>();
    } else {
      return new SerializationWrapperCodec<T>();
    }
  }

  private static class IdentityCodec<T> implements ValueCodec<T> {
    @Override
    public Object encode(T input) {
      return input;
    }

    @Override
    @SuppressWarnings("unchecked")
    public T decode(Object input) {
      return (T) input;
    }
  }

  private static class SerializationWrapperCodec<T> implements ValueCodec<T> {
    @Override
    public Object encode(T input) {
      if (input == null) {
        return null;
      }
      ByteArrayOutputStream baos = new ByteArrayOutputStream();
      try {
        ObjectOutputStream oos = new ObjectOutputStream(baos);
        try {
          oos.writeObject(input);
        } catch(IOException e) {
          throw new RuntimeException("Object cannot be serialized", e);
        } finally {
          oos.close();
        }
      } catch(IOException e) {
        // ignore
      }
      return new ValueWrapper(input.hashCode(), baos.toByteArray());
    }

    @Override
    public T decode(Object input) {
      if (input == null) {
        return null;
      }
      ValueWrapper data = (ValueWrapper) input;
      ByteArrayInputStream bais = new ByteArrayInputStream(data.getValue());
      try {
        ObjectInputStream ois = new ObjectInputStream(bais);
        try {
          @SuppressWarnings("unchecked")
          T result = (T) ois.readObject();
          return result;
        } catch (ClassNotFoundException e) {
          throw new RuntimeException("Could not load class", e);
        } finally {
          ois.close();
        }
      } catch(IOException e) {
        // ignore
      }
      throw new AssertionError("Cannot reach here!");
    }
  }
}