/*
    * Copyright (c) 2012-2014, Dienst Landelijk Gebied - Ministerie van Economische Zaken
    *
    * Gepubliceerd onder de BSD 2-clause licentie,
    * zie https://github.com/MinELenI/CBSviewer/blob/master/LICENSE.md voor de volledige licentie.
    */
   package nl.mineleni.cbsviewer.servlet.wms;
   
   import java.io.BufferedReader;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.InputStreamReader;
  import java.io.Reader;
  import java.io.StringWriter;
  import java.io.Writer;
  import java.util.Iterator;
  
  import javax.xml.parsers.ParserConfigurationException;
  
  import nl.mineleni.cbsviewer.util.LabelsBundle;
  import nl.mineleni.cbsviewer.util.xml.LayerDescriptor;
  
  import org.geotools.GML;
  import org.geotools.GML.Version;
  import org.geotools.data.simple.SimpleFeatureCollection;
  import org.geotools.data.simple.SimpleFeatureIterator;
  import org.geotools.feature.DefaultFeatureCollection;
  import org.geotools.feature.simple.SimpleFeatureBuilder;
  import org.geotools.feature.simple.SimpleFeatureTypeBuilder;
  import org.jsoup.Jsoup;
  import org.jsoup.nodes.Element;
  import org.opengis.feature.simple.SimpleFeature;
  import org.opengis.feature.simple.SimpleFeatureType;
  import org.opengis.geometry.primitive.Point;
  import org.opengis.referencing.crs.CoordinateReferenceSystem;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.xml.sax.SAXException;
  
  /**
   * Utility klasse FeatureInfoResponseConverter kan gebruikt worden om
   * FeatureInfo responses te parsen en te converteren naar een andere vorm.
   *
   * @author mprins
   * @since 1.7
   *
   * @has 1 - 1 AttributesNamesFilter
   * @has 1 - 1 AttributeValuesFilter
   */
  public final class FeatureInfoResponseConverter {
  
  	/**
  	 * ondersteunde typen voor conversie.
  	 */
  	public enum CONVERTER_TYPE {
  
  		/** The gmltype. */
  		GMLTYPE("application/vnd.ogc.gml"),
  		/** The htmltype. */
  		HTMLTYPE("text/html"),
  		/** xml type. (UNSUPPORTED) */
  		XMLTYPE("application/vnd.ogc.wms_xml");
  
  		/** het conversie type. */
  		private final String type;
  
  		/**
  		 * enum constructor.
  		 *
  		 * @param type
  		 *            het conversie type
  		 */
  		CONVERTER_TYPE(final String type) {
  			this.type = type;
  		}
  
  		/**
  		 * String value van dit object.
  		 *
  		 * @return de waarde van dit object als string
  		 * @see java.lang.Enum#toString()
  		 * @see java.lang.Number#toString()
  		 */
  		@Override
  		public String toString() {
  			return this.type;
  		}
  	}
  
  	/** byte array buffer size, 1KB. */
  	private static final int BUFFERSIZE = 1024;
  
  	/** logger. */
  	private static final Logger LOGGER = LoggerFactory
  	        .getLogger(FeatureInfoResponseConverter.class);
  
  	/** attribuut namen filter. */
  	private static final AttributesNamesFilter NAMESFILTER = new AttributesNamesFilter();
  
 	/** resource bundle. */
 	private static final LabelsBundle RESOURCES = new LabelsBundle();
 
 	/** attribuut waarden filter. */
 	private static final AttributeValuesFilter VALUESFILTER = new AttributeValuesFilter();
 
 	/**
 	 * private constructor.
 	 */
 	private FeatureInfoResponseConverter() {
 		// private constructor voor utility klasse
 	}
 
 	/**
 	 * Cleanup html.
 	 *
 	 * @param htmlStream
 	 *            input HTML stream, bijvoorbeeld uit een GetFeatureInfo
 	 *            request.
 	 * @param layer
 	 *            De laag waarvoor deze functie wordt uitgevoerd
 	 * @return opgeschoonde html tabel
 	 * @throws IOException
 	 *             Signals that an I/O exception has occurred.
 	 */
 	private static String cleanupHTML(final InputStream htmlStream,
 	        final LayerDescriptor layer) throws IOException {
 		final Element table = Jsoup.parse(convertStreamToString(htmlStream))
 		        .select("table").first();
 		if (table == null) {
 			LOGGER.debug("Geen attribuut info voor deze locatie/zoomnivo.");
 			return RESOURCES.getString("KEY_INFO_GEEN_FEATURES");
 		}
 
 		final DefaultFeatureCollection featureCollection = new DefaultFeatureCollection(
 		        "internal");
 		final SimpleFeatureTypeBuilder b = new SimpleFeatureTypeBuilder();
 
 		// 1e rij zijn headers, andere rijen zijn data, geheel converteren naar
 		// een SimpleFeatureCollection
 		final Element headers = table.select("tr:first-child").first();
 		if (headers != null) {
 			final Iterator<Element> iterTHs = headers.select("th").iterator();
 			while (iterTHs.hasNext()) {
 				b.add(iterTHs.next().text(), String.class);
 			}
 		}
 		b.setDefaultGeometry("point");
 		b.setCRS(null);
 		b.nillable(true).add("point", Point.class,
 		        (CoordinateReferenceSystem) null);
 		b.setName("tablerow");
 		final SimpleFeatureType type = b.buildFeatureType();
 		final SimpleFeatureBuilder builder = new SimpleFeatureBuilder(type);
 		final Iterator<Element> rows = table.select("tr:not(:first-child)")
 		        .iterator();
 		while (rows.hasNext()) {
 			final Iterator<Element> iterTH = headers.select("th").iterator();
 			final Iterator<Element> iterTDs = rows.next().select("td")
 			        .iterator();
 			final SimpleFeature f = builder.buildFeature(null);
 			while (iterTDs.hasNext()) {
 				f.setAttribute(iterTH.next().text(), iterTDs.next().text());
 			}
 			f.setDefaultGeometry(null);
 			featureCollection.add(f);
 		}
 
 		return featureCollectionConverter(featureCollection, layer);
 	}
 
 	/**
 	 * Converteer gml imputstream naar html tabel of een lege string.
 	 *
 	 * @param gmlStream
 	 *            input GML stream, bijvoorbeeld uit een GetFeatureInfo request.
 	 * @param layer
 	 *            De laag waarvoor deze functie wordt uitgevoerd
 	 * @return een html tabel
 	 * @throws IOException
 	 *             Signals that an I/O exception has occurred.
 	 */
 	private static String convertGML(final InputStream gmlStream,
 	        final LayerDescriptor layer) throws IOException {
 		try {
 			final GML gml = new GML(Version.WFS1_0);
 			return featureCollectionConverter(
 			        gml.decodeFeatureCollection(gmlStream), layer);
 		} catch (ParserConfigurationException | SAXException e) {
 			LOGGER.error("Fout tijdens parsen van GML. ", e);
 			return "";
 		} finally {
 			gmlStream.close();
 		}
 
 	}
 
 	/**
 	 * Converteert een stream naar een string.
 	 *
 	 * @param is
 	 *            de InputStream met data
 	 * @return de data als string
 	 * @throws IOException
 	 *             Signals that an I/O exception has occurred.
 	 */
 	private static String convertStreamToString(final InputStream is)
 	        throws IOException {
 		final Writer writer = new StringWriter();
 		if (is != null) {
 
 			final char[] buffer = new char[BUFFERSIZE];
 			try {
 				final Reader reader = new BufferedReader(new InputStreamReader(
 				        is, "UTF-8"));
 				int n;
 				while ((n = reader.read(buffer)) != -1) {
 					writer.write(buffer, 0, n);
 				}
 			} finally {
 				is.close();
 			}
 		}
 		return writer.toString();
 	}
 
 	/**
 	 * Converteer de input naar een html tabel.
 	 *
 	 * @param input
 	 *            inputstream met de featureinfo response.
 	 * @param type
 	 *            het type conversie, ondersteund zijn {@code "GMLTYPE"} en
 	 *            {@code "HTMLTYPE"}
 	 * @param layer
 	 *            De laag waarvoor deze functie wordt uitgevoerd
 	 * @return een html tabel
 	 * @throws IOException
 	 *             Signals that an I/O exception has occurred.
 	 */
 	public static String convertToHTMLTable(final InputStream input,
 	        final CONVERTER_TYPE type, final LayerDescriptor layer)
 	        throws IOException {
 		switch (type) {
 		case GMLTYPE:
 			return convertGML(input, layer);
 		case HTMLTYPE:
 			return cleanupHTML(input, layer);
 		case XMLTYPE:
 			throw new IOException(CONVERTER_TYPE.XMLTYPE
 			        + " (XMLTYPE) wordt niet ondersteund.");
 		default:
 			return convertStreamToString(input);
 		}
 	}
 
 	/**
 	 * Feature collection converter.
 	 *
 	 * @param features
 	 *            verzameling features die wordt omgezet
 	 * @param layer
 	 *            De laag waarvoor deze functie wordt uitgevoerd
 	 * @return the string
 	 */
 	private static String featureCollectionConverter(
 	        final SimpleFeatureCollection features, final LayerDescriptor layer) {
 
 		final StringBuilder sb = new StringBuilder();
 		final String[] fieldNames = layer.getAttributes().split(",\\s*");
 
 		if ((features != null) && (features.size() > 0)) {
 			// tabel maken
 			sb.append("<table id=\"attribuutTabel\" class=\"attribuutTabel\">");
 			sb.append("<caption>");
 			sb.append(RESOURCES.getString("KEY_INFO_TABEL_CAPTION"));
 			sb.append("</caption><thead><tr>");
 			for (final String n : fieldNames) {
 				sb.append("<th scope=\"col\">");
 				sb.append(NAMESFILTER.filterValue(n, layer.getId()));
 				sb.append("</th>");
 			}
 			sb.append("</tr></thead><tbody>");
 			int i = 0;
 			SimpleFeatureIterator iter = features.features();
 			while (iter.hasNext()) {
 				sb.append("<tr class=\"")
 				        .append(((i++ % 2) == 0) ? "odd" : "even")
 				        .append("\">");
 				final SimpleFeature f = iter.next();
 				for (final String n : fieldNames) {
 					if (VALUESFILTER.hasFilters()) {
 						sb.append("<td>")
 						        .append(VALUESFILTER.filterValue(f
 						                .getAttribute(n))).append("</td>");
 					} else {
 						sb.append("<td>").append(f.getAttribute(n))
 						        .append("</td>");
 					}
 				}
 				sb.append("</tr>");
 			}
 			sb.append("</tbody></table>");
 			iter.close();
 			iter = null;
 			LOGGER.debug("Gemaakte HTML tabel: " + sb);
 			return sb.toString();
 		} else {
 			LOGGER.debug("Geen attribuut info voor deze locatie/zoomnivo.");
 			return RESOURCES.getString("KEY_INFO_GEEN_FEATURES");
 		}
 	}
 }