/*
    * Licensed to The Apereo Foundation under one or more contributor license
    * agreements. See the NOTICE file distributed with this work for additional
    * information regarding copyright ownership.
    *
    *
    * The Apereo Foundation licenses this file to you under the Educational
    * Community 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://opensource.org/licenses/ecl2.txt
   *
   * 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.opencastproject.graphql.datafetcher.event;
  
  import org.opencastproject.elasticsearch.api.SearchIndexException;
  import org.opencastproject.elasticsearch.index.ElasticsearchIndex;
  import org.opencastproject.elasticsearch.index.objects.event.Event;
  import org.opencastproject.graphql.datafetcher.ContextDataFetcher;
  import org.opencastproject.graphql.event.GqlEvent;
  import org.opencastproject.graphql.exception.GraphQLNotFoundException;
  import org.opencastproject.graphql.exception.GraphQLRuntimeException;
  import org.opencastproject.graphql.exception.OpencastErrorType;
  import org.opencastproject.graphql.execution.context.OpencastContext;
  import org.opencastproject.index.service.api.IndexService;
  import org.opencastproject.index.service.exception.IndexServiceException;
  import org.opencastproject.index.service.impl.util.EventUtils;
  import org.opencastproject.metadata.dublincore.DublinCoreMetadataCollection;
  import org.opencastproject.metadata.dublincore.EventCatalogUIAdapter;
  import org.opencastproject.metadata.dublincore.MetadataField;
  import org.opencastproject.security.api.SecurityService;
  
  import com.entwinemedia.fn.data.Opt;
  
  import java.text.DateFormat;
  import java.text.ParseException;
  import java.text.SimpleDateFormat;
  import java.util.Date;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.TimeZone;
  
  import graphql.schema.DataFetchingEnvironment;
  
  public class CommonEventMetadataDataFetcher implements ContextDataFetcher<Map<String, Object>> {
  
    @Override
    public Map<String, Object> get(OpencastContext opencastContext, DataFetchingEnvironment dataFetchingEnvironment) {
      String eventId = ((GqlEvent)dataFetchingEnvironment.getSource()).id();
      SecurityService securityService = opencastContext.getService(SecurityService.class);
      ElasticsearchIndex searchIndex = opencastContext.getService(ElasticsearchIndex.class);
      IndexService indexService = opencastContext.getService(IndexService.class);
  
      try {
        GqlEvent e = getEvent(searchIndex, eventId, securityService);
        Event event = getEventFromIndexService(indexService, eventId, searchIndex);
        EventCatalogUIAdapter eventCatalogUiAdapter = indexService.getCommonEventCatalogUIAdapter();
        DublinCoreMetadataCollection collection = EventUtils.getEventMetadata(event, eventCatalogUiAdapter);
  
        return getOutputFields(collection);
      } catch (SearchIndexException | ParseException | IndexServiceException e) {
        throw new GraphQLRuntimeException(OpencastErrorType.InternalError, e);
      }
    }
  
    private GqlEvent getEvent(ElasticsearchIndex searchIndex, String eventId, SecurityService securityService)
            throws SearchIndexException {
      return searchIndex.getEvent(eventId, securityService.getOrganization().toString(), securityService.getUser())
          .map(GqlEvent::new).orElseThrow(() -> new GraphQLNotFoundException(
                  String.format("Could not resolve to a %s with the id of %s", GqlEvent.TYPE_NAME, eventId)));
    }
  
    private Event getEventFromIndexService(IndexService indexService, String eventId, ElasticsearchIndex searchIndex)
            throws IndexServiceException, SearchIndexException {
      Opt<Event> opt = indexService.getEvent(eventId, searchIndex);
      if (opt.isEmpty()) {
        throw new GraphQLNotFoundException(
            String.format("Could not resolve to a %s with the id of %s", GqlEvent.TYPE_NAME, eventId));
      }
      return opt.get();
    }
  
    private Map<String, Object> getOutputFields(DublinCoreMetadataCollection collection) {
      Map<String, Object> result = new HashMap<>();
      collection.getOutputFields().values().forEach(f -> {
        Object value = f.getValue();
        String outputID = f.getOutputID();
        MetadataField.Type type = f.getType();
  
        if (type.equals(MetadataField.Type.DATE)) {
          Date date = (Date) value;
         if (date != null) {
           DateFormat df = new SimpleDateFormat(f.getPattern());
           df.setTimeZone(TimeZone.getTimeZone("UTC"));
           result.put(outputID, df.format(date));
         }
       } else if (type.equals(MetadataField.Type.DURATION)) {
         if (value instanceof String) {
           result.put(outputID, Long.parseLong(((String) value).isEmpty() ? "0" : (String) value));
         } else if (value instanceof Long || value instanceof Integer) {
           result.put(outputID, value);
         }
       } else {
         result.put(outputID, value);
       }
     });
     return result;
   }
 }