/*
 * 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.beam.runners.mapreduce.translation;

import static com.google.common.base.Preconditions.checkNotNull;

import com.fasterxml.jackson.databind.Module;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.Serializable;
import org.apache.beam.sdk.io.FileSystems;
import org.apache.beam.sdk.options.PipelineOptions;
import org.apache.beam.sdk.util.common.ReflectHelpers;

/**
 * Encapsulates the PipelineOptions in serialized form to ship them to the cluster.
 */
public class SerializedPipelineOptions implements Serializable {

  private final byte[] serializedOptions;

  /** Lazily initialized copy of deserialized options. */
  private transient PipelineOptions pipelineOptions;

  public SerializedPipelineOptions(PipelineOptions options) {
    checkNotNull(options, "PipelineOptions must not be null.");

    try (ByteArrayOutputStream baos = new ByteArrayOutputStream()) {
      createMapper().writeValue(baos, options);
      this.serializedOptions = baos.toByteArray();
    } catch (Exception e) {
      throw new RuntimeException("Couldn't serialize PipelineOptions.", e);
    }

  }

  public PipelineOptions getPipelineOptions() {
    if (pipelineOptions == null) {
      try {
        pipelineOptions = createMapper().readValue(serializedOptions, PipelineOptions.class);

        FileSystems.setDefaultPipelineOptions(pipelineOptions);
      } catch (IOException e) {
        throw new RuntimeException("Couldn't deserialize the PipelineOptions.", e);
      }
    }

    return pipelineOptions;
  }

  /**
   * Use an {@link ObjectMapper} configured with any {@link Module}s in the class path allowing
   * for user specified configuration injection into the ObjectMapper. This supports user custom
   * types on {@link PipelineOptions}.
   */
  private static ObjectMapper createMapper() {
    return new ObjectMapper().registerModules(
        ObjectMapper.findModules(ReflectHelpers.findClassLoader()));
  }
}