package waypoints;

import static org.openstreetmap.josm.tools.I18n.tr;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

import javax.xml.parsers.SAXParserFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.openstreetmap.josm.data.coor.LatLon;
import org.openstreetmap.josm.data.osm.DataSet; // NW
import org.openstreetmap.josm.data.osm.Node; // NW
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.InputSource;
import org.xml.sax.helpers.DefaultHandler;

/**
 * Read waypoints from a GPX file and convert to nodes.
 */
public class WaypointReader {

    private static class Parser extends DefaultHandler {
        /**
         * Current track to be read. The last entry is the current trkpt.
         * If in wpt-mode, it contain only one GpsPoint.
         */
        private DataSet dataSet;
        private LatLon currentLatLon;
        private String curWptName;
        private  boolean inName = false;

        // NW start
        // data now has two components: the GPS points and an OsmDataLayer.
        // This is to allow us to convert waypoints straight to nodes.
        // The way this works is that waypoints with a name not beginning
        // with 0 - i.e. waypoints specially named - will be loaded in as
        // nodes, in addition to going into the gpx layer. Other waypoints will
        // only go into the gpx layer.
        public Parser()
        {
            dataSet = new DataSet();
        }
        // NW end

        @Override public void startElement(String namespaceURI,
                String localName, String qName, Attributes atts)
                    throws SAXException {
            if (qName.equals("wpt")) {
                try {
                    double lat = Double.parseDouble(atts.getValue("lat"));
                    double lon = Double.parseDouble(atts.getValue("lon"));
                    if (Math.abs(lat) > 90)
                        throw new SAXException
                        (tr("Data error: lat value \"{0}\" is out of bounds.",
                            lat));
                    if (Math.abs(lon) > 180)
                        throw new SAXException
                        (tr("Data error: lon value \"{0}\" is out of bounds.",
                            lon));
                    currentLatLon = new LatLon(lat, lon);
                } catch (NumberFormatException e) {
                    e.printStackTrace();
                    throw new SAXException(e);
                }
            }
            else if (qName.equals("name")) {
                inName = true;
                curWptName = "";
            }
        }

        @Override public void characters(char[] ch, int start, int length) {
            // NW start
            if (inName) {
                curWptName = new String (ch,start,length);
            }
            // NW end
        }

        @Override public void endElement(String namespaceURI, String localName,
                                        String qName) {
            if (qName.equals("wpt") && curWptName!="") {
                // create a new node from the latitude and longitude
                System.out.println("Found a waypoint to convert to a node: "
                                        + curWptName);
                Node node = new Node(currentLatLon);
                node.put("name",curWptName);
                dataSet.nodes.add(node);
            }
            else if (qName.equals("name")) {
                inName = false;
            }
        }
    }

    /**
     * Parse and return the read data
     */
    public static DataSet parse(InputStream source)
            throws SAXException, IOException, ParserConfigurationException {
        Parser parser = new Parser();
        SAXParserFactory.newInstance().newSAXParser().parse(new InputSource(new InputStreamReader(source, "UTF-8")), parser);
        return parser.dataSet;
    }
}