/*
    * 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.wikimedia.gobblin.converter;
  
  import java.util.Optional;
  import java.util.stream.Collectors;
  import java.util.stream.StreamSupport;
  
  import org.apache.gobblin.configuration.WorkUnitState;
  import org.apache.gobblin.converter.Converter;
  import org.apache.gobblin.converter.DataConversionException;
  import org.apache.gobblin.converter.SchemaConversionException;
  import org.apache.gobblin.util.ForkOperatorUtils;
  import org.wikimedia.gobblin.TimestampedRecord;
  
  import com.google.common.base.Preconditions;
  
  
  public class TimestampedRecordConverterWrapper<I, O>
          extends Converter<String, String, TimestampedRecord<I>, TimestampedRecord<O>> {
  
      public static final String CONVERTER_TIMESTAMPED_RECORD_WRAPPED = "converter.timestampedrecord.wrapped.class";
  
      private Converter<String, String, I, O> wrappedConverter;
  
      @Override
      public Converter<String, String, TimestampedRecord<I>, TimestampedRecord<O>> init(WorkUnitState workUnit) {
          String wrappedConverterClassKey = ForkOperatorUtils.getPropertyNameForBranch(workUnit, CONVERTER_TIMESTAMPED_RECORD_WRAPPED);
  
          Preconditions.checkArgument(workUnit.contains(wrappedConverterClassKey),
                  "The converter " + this.getClass().getName() + " cannot be used without setting the property "
                          + CONVERTER_TIMESTAMPED_RECORD_WRAPPED);
  
          try {
              wrappedConverter = (Converter) Class.forName(workUnit.getProp(wrappedConverterClassKey)).getDeclaredConstructor().newInstance();
          } catch (Exception e) {
              throw new RuntimeException("Problem instantiating wrapper converter class: " +
                      workUnit.getProp(wrappedConverterClassKey), e);
          }
  
          return this;
      }
  
      @Override
      public String convertSchema(String inputSchema, WorkUnitState workUnit) throws SchemaConversionException {
          return inputSchema;
      }
  
      @Override
      public Iterable<TimestampedRecord<O>> convertRecord(String outputSchema, TimestampedRecord<I> inputRecord, WorkUnitState workUnit)
              throws DataConversionException {
          Iterable<O> convertedOutput = wrappedConverter.convertRecord(outputSchema, inputRecord.getPayload(), workUnit);
          Optional<Long> recordTimestamp = inputRecord.getTimestamp();
          return StreamSupport.stream(convertedOutput.spliterator(), false).
                  map(outputItem -> new TimestampedRecord<O>(outputItem, recordTimestamp))
                  .collect(Collectors.toList());
      }
  
  }