/*
 * 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.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import javax.xml.parsers.ParserConfigurationException;

import org.dom4j.Document;
import org.dom4j.Element;
import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartFrame;
import org.jfree.chart.ChartUtilities;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.data.xy.XYSeries;
import org.jfree.data.xy.XYSeriesCollection;
import org.wamblee.general.Pair;
import org.wamblee.gps.coordinates.Point;
import org.wamblee.gps.coordinates.ReferenceCoordinateSystem;
import org.wamblee.gps.track.Track;
import org.wamblee.gps.track.TrackPoint;
import org.wamblee.xml.DomUtils;
import org.xml.sax.SAXException;

/**
 * Parses a GPX file and prints out a data file with each trackpoints distance from the start of the 
 * track and its elevation, separated by a space. 
 */
public class GpxPlotter {
    
    public static void main(String[] aArgs) throws ParserConfigurationException, FileNotFoundException, SAXException, IOException { 
        File file = new File(aArgs[0]); 
        Document doc = DomUtils.convert(DomUtils.read(new FileInputStream(file)));
        
        Track track = parseTrack(doc);
    
        List<Pair<Double,Double>> elevationProfile = computeElevationProfile(track);
        printTrack(elevationProfile); 
        computeTotalClimb(elevationProfile);
        plotElevationProfile(elevationProfile);
    }

    /**
     * @param doc
     */
    private static Track parseTrack(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 static TrackPoint parseTrackPoint(Element trkpt) {
        //System.out.println(trkpt.asXML() + "|\n"); 
        double latitude = new Double(trkpt.attributeValue("lat"));
        double longitude = new Double(trkpt.attributeValue("lon"));
        double elevation = new Double(trkpt.elementText("ele"));
        //System.out.println("  lat = " + lat + " lon = " + lon + " ele = " + ele);
        return new TrackPoint(latitude, longitude, elevation);
    }
    
    private static List<Pair<Double, Double>> computeElevationProfile(Track aTrack) {
        List<Pair<Double,Double>> results = new ArrayList<Pair<Double,Double>>();
        double distance = 0.0; 
        for (int i = 0; i < aTrack.size(); i++) { 
            Point point = aTrack.getPoint(i);
            results.add(new Pair<Double,Double>(distance, point.getCoordinates().getX3()));
            if ( i+1 < aTrack.size()) { 
                Point nextPoint = aTrack.getPoint(i+1); 
                distance += ReferenceCoordinateSystem.distance(point, nextPoint);
            }
        }
        return results; 
    }
    
    private static void printTrack(List<Pair<Double,Double>> aHeightProfile) { 
       for (Pair<Double,Double> point: aHeightProfile) { 
           System.out.println(point.getFirst() + " " + point.getSecond());
       }
    }
    
    private static void computeTotalClimb(List<Pair<Double,Double>> aHeightProfile) {
        double result = 0.0;
        
        double lastHeight = aHeightProfile.get(0).getSecond();
        for ( int i = 1; i < aHeightProfile.size(); i++) { 
            double height = aHeightProfile.get(i).getSecond();
            if ( height > lastHeight) { 
                result += (height-lastHeight); 
            }
            lastHeight = height; 
        }
        System.out.println("Total climb: " + result);
    }
    
    private static void plotElevationProfile(List<Pair<Double,Double>> aHeightProfile) throws IOException {
        XYSeries series = new XYSeries("height");
        for (Pair<Double,Double> point: aHeightProfile) { 
            series.add(point.getFirst(), point.getSecond());
        }
        XYSeriesCollection dataset = new XYSeriesCollection(series);
        JFreeChart chart = ChartFactory.createXYLineChart(
                "Height Profile", 
                "Distance(m)",
                "Height(m)",
                dataset,
                PlotOrientation.VERTICAL,
                true,
                true,
                false);
        ChartUtilities.writeChartAsPNG(new FileOutputStream("test.png"), chart, 600, 300);
        ChartFrame frame = new ChartFrame("test", chart);
        frame.pack();
        frame.setVisible(true);
    }

}