/*
 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.
 */

import java.util.ArrayList;
import java.util.List;

import org.codehaus.jackson.JsonNode;

public class TransformerSplitAndGet implements Transformer {
  private final List<String> delimeter;
  private final int get;

  public TransformerSplitAndGet(JsonNode json) throws Exception {
    if(JsonFile.empty(json, "delimeter")) {
      throw new Exception("SplitAndGet delimeter not defined");
    }

    if(JsonFile.empty(json, "get")) {
      throw new Exception("SplitAndGet get not defined");
    }

    delimeter = new ArrayList<>();
    delimeter.add(json.get("delimeter").asText());
    
    get = Integer.parseInt(json.get("get").asText());

    if(get < -1) {
      throw new Exception("Invalid value of get for SplitAndGet: " + get);
    }
  }

  @Override
  public String transform(String input) throws Exception {
    List<String> parts = DeviceMapClient.split(input, delimeter);
    
    int i = get;

    if(get == -1) {
      i = parts.size() - 1;
    }

    if(i < 0 || i >= parts.size()) {
      throw new Exception("SplitAndGet index out of range: " + i);
    }

    return parts.get(i);
  }

  @Override
  public String toString() {
    return "SplitAndGet  delimeter: '" + delimeter + "'  get: " + get;
  }
}