/*
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.streams.converter;

import org.apache.streams.data.DocumentClassifier;
import org.apache.streams.data.util.ActivityUtil;
import org.apache.streams.jackson.StreamsJacksonMapper;
import org.apache.streams.pojo.json.Activity;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.ObjectNode;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

/**
 * Ensures generic String and ObjectNode documents can be converted to Activity
 *
 * <p/>
 * BaseDocumentClassifier is included by default in all
 * @see org.apache.streams.converter.ActivityConverterProcessor
 *
 */
public class BaseDocumentClassifier implements DocumentClassifier {

  private ObjectMapper mapper = StreamsJacksonMapper.getInstance();

  private static final Logger LOGGER = LoggerFactory.getLogger(BaseDocumentClassifier.class);

  @Override
  @SuppressWarnings("unchecked")
  public List<Class> detectClasses(Object document) {

    Activity activity;
    ObjectNode node = null;

    List<Class> classes = new ArrayList<>();
    // Soon javax.validation will available in jackson
    //   That will make this simpler and more powerful
    if ( document instanceof String ) {
      classes.add(String.class);
      try {
        activity = this.mapper.readValue((String)document, Activity.class);
        if (activity != null && ActivityUtil.isValid(activity)) {
          classes.add(Activity.class);
        }
      } catch (IOException e1) {
        try {
          node = this.mapper.readValue((String)document, ObjectNode.class);
          classes.add(ObjectNode.class);
        } catch (IOException ignored) {
          LOGGER.trace("ignoring ", ignored);
        }
      }
    } else if ( document instanceof ObjectNode ) {
      classes.add(ObjectNode.class);
      activity = this.mapper.convertValue(document, Activity.class);
      if (ActivityUtil.isValid(activity)) {
        classes.add(Activity.class);
      }
    } else {
      classes.add(document.getClass());
    }

    return classes;

  }

}
