/**
 * 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.metron.common.field.transformation;

import org.apache.metron.stellar.dsl.Context;

import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

public class RenameTransformation implements FieldTransformation{
  @Override
  public Map<String, Object> map( Map<String, Object> input
                                , List<String> outputField
                                , LinkedHashMap<String, Object> fieldMappingConfig
                                , Context context
                                , Map<String, Object>... sensorConfig
                                )
  {
    if(fieldMappingConfig == null || fieldMappingConfig.isEmpty()) {
      return input;
    }
    Map<String, Object> ret = new HashMap<>();
    for(Map.Entry<String, Object> kv : input.entrySet()) {
      Object renamed = fieldMappingConfig.get(kv.getKey());
      if(renamed != null) {
        //if we're renaming, then we want to copy the field to the new name
        ret.put(renamed.toString(), kv.getValue());
        //and remove the old field
        ret.put(kv.getKey(), null);
      }
      else {
        ret.put(kv.getKey(), kv.getValue());
      }
    }
    return ret;
  }
}
