/*
 * 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.sdk.io.gcp.pubsublite.internal;

import com.google.protobuf.InvalidProtocolBufferException;
import com.google.protobuf.Message;
import java.io.Serializable;
import org.apache.beam.sdk.transforms.MapElements;
import org.apache.beam.sdk.transforms.PTransform;
import org.apache.beam.sdk.transforms.SimpleFunction;
import org.apache.beam.sdk.values.PCollection;

public class ProtoFromBytes<T extends Message>
    extends PTransform<PCollection<byte[]>, PCollection<T>> {
  interface ProtoParser<T2> extends Serializable {
    T2 parse(byte[] bytes) throws InvalidProtocolBufferException;
  }

  private final ProtoParser<T> parser;

  ProtoFromBytes(ProtoParser<T> parser) {
    this.parser = parser;
  }

  @Override
  public PCollection<T> expand(PCollection<byte[]> input) {
    return input.apply(
        MapElements.via(
            new SimpleFunction<byte[], T>() {
              @Override
              public T apply(byte[] bytes) {
                try {
                  return parser.parse(bytes);
                } catch (InvalidProtocolBufferException e) {
                  throw new RuntimeException(e);
                }
              }
            }));
  }
}
