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Refactor into GPX-based route simulation engine #6

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Merged
simonech merged 4 commits into from
Feb 19, 2026
Merged

Refactor into GPX-based route simulation engine #6

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a5e1a23
Initial plan
Copilot Feb 19, 2026
b1375fc
Refactor App into Route-Based Simulation (GPX First Step)
Copilot Feb 19, 2026
83592f4
Address review feedback: DateTimeOffset, duplicate point guard, workf…
Copilot Feb 19, 2026
86df644
Skip track points with missing elevation in GpxParser
Copilot Feb 19, 2026
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10 changes: 5 additions & 5 deletions .github/workflows/build.yml
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Original file line number Diff line number Diff line change
Expand Up @@ -30,11 +30,11 @@ jobs:
- name: Test application runs
run: |
cd VirtualSpeed/VirtualSpeed
dotnet run --no-build --configuration Release -- powerData.tcx
if [ -f powerData_fixed.tcx ]; then
echo "✓ Application successfully generated output file"
ls -lh powerData_fixed.tcx
output=$(dotnet run --no-build --configuration Release -- --gpx route.gpx)
echo "$output"
if echo "$output" | grep -q "Total Distance:"; then
echo "✓ Application produced expected output"
else
echo "✗ Application did not generate expected output file"
echo "✗ Application did not produce expected output"
exit 1
fi
10 changes: 10 additions & 0 deletions VirtualSpeed/VirtualSpeed/Model/RouteSegment.cs
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Original file line number Diff line number Diff line change
@@ -0,0 +1,10 @@
namespace VirtualSpeed.Model
{
public record RouteSegment(
double StartDistanceMeters,
double LengthMeters,
double StartElevationMeters,
double EndElevationMeters,
double AverageGradient
);
}
11 changes: 11 additions & 0 deletions VirtualSpeed/VirtualSpeed/Model/TrackPoint.cs
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Original file line number Diff line number Diff line change
@@ -0,0 +1,11 @@
using System;

namespace VirtualSpeed.Model
{
public record TrackPoint(
double Latitude,
double Longitude,
double ElevationMeters,
DateTimeOffset? Timestamp
);
}
190 changes: 28 additions & 162 deletions VirtualSpeed/VirtualSpeed/Program.cs
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Original file line number Diff line number Diff line change
@@ -1,193 +1,59 @@
using System;
using System.Collections.Generic;
using System.Globalization;
using System;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Xml;
using System.IO;
using VirtualSpeed.Services;

namespace VirtualSpeed
{
class Program
{

static void Main(string[] args)
{
// abort execution if filename is missing
if (args.Length == 0)
if (args.Length < 2 || args[0] != "--gpx")
{
Console.WriteLine("Error : tcx file name is missing !");
Console.WriteLine("Usage: app.exe --gpx <route.gpx>");
return;
}

string filename = args[0];
var calc = new VirtualSpeedCalculator();
string filePath = args[1];

XmlDocument myXmlDocument = new XmlDocument();
var parser = new GpxParser();
var builder = new RouteBuilder();

// try to open the xml file and abort if any exception is raised
System.Collections.Generic.IEnumerable<Model.TrackPoint> points;
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Unnecessary fully qualified type name. Add 'using System.Collections.Generic;' at the top of the file and change this line to just 'IEnumerable points;' for consistency with the rest of the code.

Copilot uses AI. Check for mistakes.
try
{
myXmlDocument.Load(filename);
points = parser.Parse(filePath);
}
catch(Exception e)
catch (Exception e)
{
Console.WriteLine("Error while loading xml file : " + e.Message);
Console.WriteLine("Error while loading GPX file: " + e.Message);
return;
}
Comment on lines +22 to 31
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The lazy enumeration from Parse() means parsing errors will occur after this try-catch block exits, when Build() materializes the IEnumerable. Consider calling .ToList() on the parsed points within the try-catch to ensure parsing errors are properly caught and reported with the "Error while loading GPX file" message.

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XmlNode trainingNode;
trainingNode = myXmlDocument.DocumentElement;
var segments = builder.Build(points);

double cumulatedDistance = 0;
DateTime prevTime = DateTime.MinValue;

foreach (XmlNode activitiesNode in trainingNode.ChildNodes)
foreach (XmlNode activityNode in activitiesNode.ChildNodes)
foreach (XmlNode lapNode in activityNode.ChildNodes)
{
if (lapNode.Name == "Lap")
{
XmlNode lapDistance = null;
XmlNode lapMaxSpeedNode = null;
XmlNode lapAvgSpeed = null;
XmlNode lapTime = null;

double lapCumulativeDistance = 0;
double lapMaxSpeed = 0;

foreach (XmlNode track in lapNode.ChildNodes)
{
if (track.Name == "DistanceMeters") {
lapDistance = track;
}
else if (track.Name == "TotalTimeSeconds")
{
lapTime = track;
}
else if (track.Name == "MaximumSpeed")
{
lapMaxSpeedNode = track;
}
else if (track.Name == "Extensions")
{
foreach (XmlNode ext in track.ChildNodes)
foreach (XmlNode LX in ext.ChildNodes)
if (LX.Name == "AvgSpeed")
lapAvgSpeed = LX;
}
else if (track.Name == "Track")
foreach (XmlNode point in track.ChildNodes)
{
XmlNode distance = null;
XmlNode time = null;
XmlNode watt = null;
XmlNode speed = null;
foreach (XmlNode value in point.ChildNodes)
{
if (value.Name == "Time")
time = value;
else if (value.Name == "DistanceMeters")
distance = value;
else if (value.Name == "Extensions")
{
foreach (XmlNode ext in value.ChildNodes)
foreach (XmlNode tcxValue in ext.ChildNodes)
{
if (tcxValue.Name == "ns3:Watts")
watt = tcxValue;
else if (tcxValue.Name == "ns3:Speed")
speed = tcxValue;
}
}
}

double newSpeed = 0.0;

// check if watt information is missing
if (watt == null)
{
// if speed node is present then keep the raw speed without adjusting it
if (speed != null)
{
// speed in tcx is in m/s
newSpeed = Double.Parse(speed.InnerText, CultureInfo.InvariantCulture) * 3600 / 1000;
}
}
else
{
newSpeed = calc.CalculateVelocity(Double.Parse(watt.InnerText));
}

var newSpeedMS = calc.ConvertKmhToMS(newSpeed);
lapMaxSpeed = Math.Max(lapMaxSpeed, newSpeedMS);

var pointDistance = calc.CalculateDistance(newSpeed, 1);
cumulatedDistance = cumulatedDistance + pointDistance;
lapCumulativeDistance = lapCumulativeDistance + pointDistance;

// DistanceMeters node might not be present in a Trackpoint node, don't try to replace it if so
if (distance != null)
distance.InnerText = cumulatedDistance.ToString(new CultureInfo("en-US"));

// speed node might not be present in an Extension node, don't try to replace it if so
if (speed != null)
speed.InnerText = newSpeedMS.ToString(new CultureInfo("en-US"));
}
}

lapDistance.InnerText= lapCumulativeDistance.ToString(new CultureInfo("en-US"));
lapMaxSpeedNode.InnerText=lapMaxSpeed.ToString(new CultureInfo("en-US"));

var avg = lapCumulativeDistance / Double.Parse(lapTime.InnerText);

lapAvgSpeed.InnerText = avg.ToString(new CultureInfo("en-US"));

}
}
myXmlDocument.Save(Path.GetFileNameWithoutExtension(filename) + "_fixed.tcx");

}

private void Test(string[] args)
{
var what = args[0];

var calc = new VirtualSpeedCalculator();

if (what.Equals("P"))
if (segments.Count == 0)
{
var speed = Double.Parse(args[1]);

var pwr = calc.CalculatePower(speed);
Console.WriteLine("Measuring Power needed to go to a given speed");
Console.WriteLine("{0} Km/h -> {1}W", speed, pwr);
Console.WriteLine("No segments found – check that the GPX file contains track points.");
return;
}
else if (what.Equals("V"))
{
var pwr = Double.Parse(args[1]);

var speed = calc.CalculateVelocity(pwr);
Console.WriteLine("Measuring Speed obtained for a given power");
Console.WriteLine("{0} W -> {1} Km/h", pwr, speed);
}
double totalDistance = segments.Sum(s => s.LengthMeters);
double totalElevationGain = segments
.Where(s => s.EndElevationMeters > s.StartElevationMeters)
.Sum(s => s.EndElevationMeters - s.StartElevationMeters);

else if (what.Equals("D"))
{
var pwr = Double.Parse(args[1]);
var time = Double.Parse(args[2]);
Console.WriteLine($"Total Distance: {totalDistance:F0} m");
Console.WriteLine($"Total Elevation Gain: {totalElevationGain:F0} m");
Console.WriteLine();
Console.WriteLine("Segments:");

var speed = calc.CalculateVelocity(pwr);
var distance = calc.CalculateDistance(speed, time);
Console.WriteLine("Measuring Distance for given power");
Console.WriteLine("{0} W for {1} sec = {2} meters", pwr, time, distance);
foreach (var seg in segments)
{
double gradientPct = seg.AverageGradient * 100;
Console.WriteLine($"{seg.StartDistanceMeters:F0}m - {seg.StartDistanceMeters + seg.LengthMeters:F0}m | Gradient: {gradientPct:F1}%");
}

Console.ReadLine();
}

}


}

52 changes: 52 additions & 0 deletions VirtualSpeed/VirtualSpeed/Services/GpxParser.cs
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@@ -0,0 +1,52 @@
using System;
using System.Collections.Generic;
using System.Globalization;
using System.Xml;
using VirtualSpeed.Model;

namespace VirtualSpeed.Services
{
public class GpxParser
{
public IEnumerable<TrackPoint> Parse(string filePath)
{
var doc = new XmlDocument();
doc.Load(filePath);

var ns = new XmlNamespaceManager(doc.NameTable);
ns.AddNamespace("gpx", "http://www.topografix.com/GPX/1/1");

// Try namespaced query first, fall back to no-namespace
var trkptNodes = doc.SelectNodes("//gpx:trk[1]/gpx:trkseg[1]/gpx:trkpt", ns);
if (trkptNodes == null || trkptNodes.Count == 0)
trkptNodes = doc.SelectNodes("//trk[1]/trkseg[1]/trkpt");

if (trkptNodes == null)
yield break;

foreach (XmlNode node in trkptNodes)
{
var latAttr = node.Attributes?["lat"]?.Value;
var lonAttr = node.Attributes?["lon"]?.Value;

if (latAttr == null || lonAttr == null)
continue;

double lat = double.Parse(latAttr, CultureInfo.InvariantCulture);
double lon = double.Parse(lonAttr, CultureInfo.InvariantCulture);

var eleNode = node.SelectSingleNode("gpx:ele", ns) ?? node.SelectSingleNode("ele");
if (eleNode == null)
continue;
double elevation = double.Parse(eleNode.InnerText, CultureInfo.InvariantCulture);

Comment on lines +35 to +42
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Missing error handling for malformed latitude and longitude values. If double.Parse fails, the exception will propagate up without a descriptive error message. Consider using double.TryParse and either skipping invalid points with a warning or providing a clearer error message indicating which track point has invalid coordinates.

Suggested change
double lat = double.Parse(latAttr, CultureInfo.InvariantCulture);
double lon = double.Parse(lonAttr, CultureInfo.InvariantCulture);
var eleNode = node.SelectSingleNode("gpx:ele", ns) ?? node.SelectSingleNode("ele");
if (eleNode == null)
continue;
double elevation = double.Parse(eleNode.InnerText, CultureInfo.InvariantCulture);
if (!double.TryParse(latAttr, NumberStyles.Float, CultureInfo.InvariantCulture, out double lat))
throw new FormatException($"Invalid latitude value '{latAttr}' in GPX track point.");
if (!double.TryParse(lonAttr, NumberStyles.Float, CultureInfo.InvariantCulture, out double lon))
throw new FormatException($"Invalid longitude value '{lonAttr}' in GPX track point.");
var eleNode = node.SelectSingleNode("gpx:ele", ns) ?? node.SelectSingleNode("ele");
if (eleNode == null)
continue;
if (!double.TryParse(eleNode.InnerText, NumberStyles.Float, CultureInfo.InvariantCulture, out double elevation))
throw new FormatException($"Invalid elevation value '{eleNode.InnerText}' in GPX track point.");

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Comment on lines +41 to +42
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Missing error handling for malformed elevation values. If double.Parse fails, the exception will propagate up without a descriptive error message. Consider using double.TryParse and either skipping invalid points with a warning or providing a clearer error message indicating which track point has invalid elevation data.

Suggested change
double elevation = double.Parse(eleNode.InnerText, CultureInfo.InvariantCulture);
if (!double.TryParse(eleNode.InnerText, NumberStyles.Float | NumberStyles.AllowThousands, CultureInfo.InvariantCulture, out var elevation))
throw new FormatException($"Invalid elevation value '{eleNode.InnerText}' in GPX track point.");

Copilot uses AI. Check for mistakes.
DateTimeOffset? timestamp = null;
var timeNode = node.SelectSingleNode("gpx:time", ns) ?? node.SelectSingleNode("time");
if (timeNode != null && DateTimeOffset.TryParse(timeNode.InnerText, null, DateTimeStyles.RoundtripKind, out var parsedTime))
timestamp = parsedTime;

yield return new TrackPoint(lat, lon, elevation, timestamp);
}
}
}
}
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