/*
 * Copyright 2006 the original author or authors.
 * 
 * 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.wamblee.gpx;

import java.io.InputStream;
import java.util.Iterator;

import org.dom4j.Document;
import org.dom4j.Element;
import org.wamblee.gps.track.Track;
import org.wamblee.gps.track.TrackPoint;
import org.wamblee.xml.DomUtils;
import org.wamblee.xml.XMLException;

/**
 * Parser for GPX tracks.  
 */
public class GpxParser {
    
    private static final String SCHEMA_RESOURCE = "gpx.xsd";
    
    public GpxParser() { 
        // Empty.
    }
    
    public Track parse(InputStream aIs) throws XMLException { 
        Document doc = DomUtils.convert(DomUtils.read(aIs));
        return parse(doc);
    }
    
    /**
     * @param doc
     */
    public Track parse(Document doc) {
        Track track = new Track(); 
        Element root = doc.getRootElement().element("trk").element("trkseg");
        for ( Iterator i =root.elementIterator("trkpt"); i.hasNext(); ) {
            Element trkpt = (Element)i.next();
            track.addPoint(parseTrackPoint(trkpt));
        }
        return track;
    }

    /**
     * @param trkpt
     */
    private TrackPoint parseTrackPoint(Element trkpt) {
        //System.out.println(trkpt.asXML() + "|\n"); 
        double latitude = new Double(trkpt.attributeValue("lat"));
        double longitude = new Double(trkpt.attributeValue("lon"));
        Element ele = trkpt.element("ele");
        double elevation = 0.0;
        if ( ele != null ) { 
            elevation = new Double(ele.getText());
        }
        //System.out.println("  lat = " + lat + " lon = " + lon + " ele = " + ele);
        return new TrackPoint(latitude, longitude, elevation);
    }

}