/*
 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 AttributeTransformer {
  private final String defaultValue;
  private final List<Transformer> transformers;

  public AttributeTransformer(JsonNode json) throws Exception {

    //PARSE ATTRIBUTE TRANSFORMER JSON

    String defaultValueStr = "";

    if(!JsonFile.empty(json, "defaultValue")) {
      defaultValueStr = json.get("defaultValue").asText();
    }

    defaultValue = defaultValueStr;
    transformers = new ArrayList<>();

    //PARSE TRANSFORMER LIST

    if(JsonFile.get(json, "transformers").isArray()) {
      for(int k = 0; k < json.get("transformers").size(); k++) {
        JsonNode transformerNode = json.get("transformers").get(k);

        Transformer transformer = DeviceMapClient.getTransformer(transformerNode);

        transformers.add(transformer);
      }
    }

    if(transformers.isEmpty()) {
      throw new Exception("No transformers defined for attributeTranformer");
    }
  }

  public String getValue(String input) throws Exception {

    //TRANSFORM INPUT
    
    for(Transformer transformer : transformers) {
      input = transformer.transform(input);
    }

    return input;
  }

  public String getDefaultValue() {
    return defaultValue;
  }

  @Override
  public String toString() {
    return "{defaultValue: '" + defaultValue + "' transformer(s): " + transformers + "}";
  }
}