/**
    * Copyright 2008-2010 Digital Enterprise Research Institute (DERI)
    *
    * Licensed 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.deri.any23.extractor.html;
  
  import org.deri.any23.extractor.ExtractionContext;
  import org.deri.any23.extractor.ExtractionException;
  import org.deri.any23.extractor.ExtractionParameters;
  import org.deri.any23.extractor.ExtractionResult;
  import org.deri.any23.extractor.Extractor.TagSoupDOMExtractor;
  import org.deri.any23.extractor.ExtractorDescription;
  import org.deri.any23.extractor.ExtractorFactory;
  import org.deri.any23.extractor.SimpleExtractorFactory;
  import org.deri.any23.rdf.Any23ValueFactoryWrapper;
  import org.deri.any23.rdf.PopularPrefixes;
  import org.openrdf.model.BNode;
  import org.openrdf.model.URI;
  import org.openrdf.model.ValueFactory;
  import org.openrdf.model.impl.ValueFactoryImpl;
  import org.w3c.dom.Document;
  
  import java.io.IOException;
  import java.util.Arrays;
  
  /**
   * Extractor for "ICBM coordinates" provided as META headers in the head
   * of an HTML page.
   *
   * @author Gabriele Renzi
   * @author Richard Cyganiak (richard@cyganiak.de)
   */
  public class ICBMExtractor implements TagSoupDOMExtractor {
  
      public final static ExtractorFactory<ICBMExtractor> factory =
              SimpleExtractorFactory.create(
                      "html-head-icbm",
                      PopularPrefixes.createSubset("geo", "rdf"),
                      Arrays.asList("text/html;q=0.01", "application/xhtml+xml;q=0.01"),
                      null,
                      ICBMExtractor.class
              );
  
      public void run(
              ExtractionParameters extractionParameters,
              ExtractionContext extractionContext,
              Document in,
              ExtractionResult out
      ) throws IOException, ExtractionException {
  
          // ICBM is the preferred method, if two values are available it is meaningless to read both
          String props = DomUtils.find(in, "//META[@name=\"ICBM\" or @name=\"geo.position\"]/@content");
          if ("".equals(props)) return;
  
          String[] coords = props.split("[;,]");
          float lat, lon;
          try {
              lat = Float.parseFloat(coords[0]);
              lon = Float.parseFloat(coords[1]);
          } catch (NumberFormatException nfe) {
              return;
          }
  
          final ValueFactory factory = new Any23ValueFactoryWrapper(ValueFactoryImpl.getInstance(), out);
          BNode point = factory.createBNode();
          out.writeTriple(extractionContext.getDocumentURI(), expand("dcterms:related"), point);
          out.writeTriple(point, expand("rdf:type"), expand("geo:Point"));
          out.writeTriple(point, expand("geo:lat"), factory.createLiteral(Float.toString(lat)));
          out.writeTriple(point, expand("geo:long"), factory.createLiteral(Float.toString(lon)));
      }
  
      private URI expand(String curie) {
          return factory.getPrefixes().expand(curie);
      }
  
      public ExtractorDescription getDescription() {
          return factory;
      }
  
  }