package uk.ac.ebi.intenz.tools.export;
   
   import java.io.OutputStream;
   import java.math.BigDecimal;
   import java.text.SimpleDateFormat;
   import java.util.Collection;
   import java.util.Date;
   
   import javax.xml.XMLConstants;
  import javax.xml.bind.JAXBContext;
  import javax.xml.bind.JAXBException;
  import javax.xml.bind.Marshaller;
  import javax.xml.validation.Schema;
  import javax.xml.validation.SchemaFactory;
  
  import org.sitemaps.ObjectFactory;
  import org.sitemaps.Url;
  import org.sitemaps.Urlset;
  import org.xml.sax.SAXException;
  
  /**
   * Exports IntEnz as a
   * <a href="http://www.google.com/webmasters/sitemaps">sitemap XML file</a>
   * @author rafalcan
   *
   */
  public class SitemapExporter {
  
  	private Marshaller marshaller;
      private ObjectFactory of;
      private final String INTENZ_URL = "http://www.ebi.ac.uk/intenz/";
  
      public SitemapExporter() throws JAXBException, SAXException{
          JAXBContext context = JAXBContext.newInstance("org.sitemaps");
          marshaller = context.createMarshaller();
          marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);
  		Schema sitemapXsd = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI)
  			.newSchema(SitemapExporter.class.getClassLoader().getResource("sitemap.xsd"));
  		marshaller.setSchema(sitemapXsd);
          of = new ObjectFactory();
  	}
  
      /**
       * Dumps a list of URLs as sitemap (see {@link http://www.sitemaps.org})
       * @param urls List of indexed URLs as Strings.
       * @param os
       * @throws JAXBException in case of marshalling error
       */
  	public void export(Collection<String> urls, OutputStream os) throws JAXBException {
  		final String CHANGE_FREQ = "weekly";
  		Urlset urlset = of.createUrlset();
  		Url intenzUrl = of.createUrl();
  		intenzUrl.setLoc(INTENZ_URL);
  		intenzUrl.setLastmod(new SimpleDateFormat("yyyy-MM-dd").format(new Date()));
  		intenzUrl.setChangefreq(CHANGE_FREQ);
  		intenzUrl.setPriority(new BigDecimal(0.8).setScale(1,BigDecimal.ROUND_DOWN));
  		urlset.getUrl().add(intenzUrl);
  		for (String url : urls) {
  			Url pageUrl = of.createUrl();
  			pageUrl.setLoc(url);
  			pageUrl.setChangefreq(CHANGE_FREQ);
  			urlset.getUrl().add(pageUrl);
  		}
  		marshaller.marshal(urlset, os);
  	}
  
  }