/*
 * Copyright (c) MuleSoft, Inc.  All rights reserved.  http://www.mulesoft.com
 * The software in this package is published under the terms of the CPAL v1.0
 * license, a copy of which has been included with this distribution in the
 * LICENSE.txt file.
 */

package org.mule.runtime.module.artifact.serializer;

import static java.lang.Class.forName;
import org.mule.runtime.module.artifact.classloader.ClassLoaderRepository;

import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectStreamClass;

/**
 * Customized version of {@link ObjectInputStream} that reads the identifier of the class loader that loaded the
 * class of the serialized object.
 * <p/>
 * Is intended to be used along with {@link ArtifactClassLoaderObjectOutputStream}.
 */
public class ArtifactClassLoaderObjectInputStream extends ObjectInputStream {

  private final ClassLoaderRepository classLoaderRepository;

  /**
   * Creates a new stream instance.
   *
   * @param classLoaderRepository contains the registered classloaders that can be used to load serialized classes. Non null.
   * @param input input stream to read from. Non null.
   * @throws  IOException if an I/O error occurs while reading stream header
   */
  public ArtifactClassLoaderObjectInputStream(ClassLoaderRepository classLoaderRepository, InputStream input)
      throws IOException {
    super(input);
    this.classLoaderRepository = classLoaderRepository;
  }

  @Override
  protected Class<?> resolveClass(ObjectStreamClass desc) throws IOException, ClassNotFoundException {
    int val = readInt();
    if (val == -1) {
      return super.resolveClass(desc);
    }

    byte[] bytes = new byte[val];
    if (read(bytes) < val) {
      throw new IOException("Stream does not contain a classloader ID");
    }

    String classLoaderId = new String(bytes);
    ClassLoader classLoader = classLoaderRepository.find(classLoaderId)
        .orElseThrow(() -> new IOException("Artifact class loader not found: " + classLoaderId));

    return forName(desc.getName(), false, classLoader);
  }
}