package org.wamblee.gpx;

import java.awt.Color;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;

import org.jfree.chart.ChartFactory;
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.geometry.Point;
import org.wamblee.gps.geometry.ReferenceCoordinateSystem;
import org.wamblee.gps.track.TrackSegment;

public class TrackStatistics implements Serializable {

    private TrackSegment _track;

    public TrackStatistics(TrackSegment aTrack) {
        _track = aTrack;
    }

    public void writeHeightProfilePng(OutputStream aStream, int aWidth,
            int aHeight) throws IOException {
        List<Pair<Double, Double>> data = computeElevationProfile();
        XYSeriesCollection dataset = createDataset(data, "height");
        JFreeChart chart = ChartFactory.createXYLineChart("Height Profile",
                "Distance(km)", "Height(m)", dataset, PlotOrientation.VERTICAL,
                true, true, false);
        chart.setBackgroundPaint(Color.WHITE);
        ChartUtilities.writeChartAsPNG(aStream, chart, aWidth, aHeight);
    }

    private static XYSeriesCollection createDataset(
            List<Pair<Double, Double>> aHeightProfile, String aName) {
        XYSeries series = new XYSeries(aName, false);
        for (Pair<Double, Double> point : aHeightProfile) {
            series.add(point.getFirst() / 1000.0, point.getSecond());
        }
        XYSeriesCollection dataset = new XYSeriesCollection(series);
        return dataset;
    }

    public List<Pair<Double, Double>> computeElevationProfile() {
        List<Pair<Double, Double>> results = new ArrayList<Pair<Double, Double>>();
        double distance = 0.0;
        for (int i = 0; i < _track.size(); i++) {
            Point point = _track.getPoint(i);
            results.add(new Pair<Double, Double>(distance, point
                    .getCoordinates().getX3()));
            if (i + 1 < _track.size()) {
                Point nextPoint = _track.getPoint(i + 1);
                distance += ReferenceCoordinateSystem
                        .distance(point, nextPoint);
            }
        }
        return results;
    }

    public double getTotalClimb() {

        List<Pair<Double, Double>> data = computeElevationProfile();
        double result = 0.0;
        if ( data.size() == 0 ) { 
            return result; 
        }

        double lastHeight = data.get(0).getSecond();
        for (int i = 1; i < data.size(); i++) {
            double height = data.get(i).getSecond();
            if (height > lastHeight) {
                result += (height - lastHeight);
            }
            lastHeight = height;
        }
        return result;
    }

    public double getDistance() {
        List<Pair<Double, Double>> data = computeElevationProfile();
        if (data.size() == 0) {
            return 0.0;
        }
        return data.get(data.size() - 1).getFirst();
    }
}