annotations/Azaion.Common/Services/GPSMatcherService.cs

using System.IO;
using Azaion.CommonSecurity;
using Azaion.CommonSecurity.DTO;
using MediatR;
using Microsoft.Extensions.Options;
using Microsoft.IdentityModel.Tokens;

namespace Azaion.Common.Services;

public interface IGpsMatcherService
{
    Task RunGpsMatching(string userRouteDir, double initialLatitude, double initialLongitude, CancellationToken detectToken = default);
    void StopGpsMatching();
}

public class GpsMatcherService(IGpsMatcherClient gpsMatcherClient, ISatelliteDownloader satelliteTileDownloader, IOptions<DirectoriesConfig> dirConfig)
    : IGpsMatcherService,
        INotificationHandler<GPSMatcherResultEvent>,
        INotificationHandler<GPSMatcherFinishedEvent>
{
    private readonly DirectoriesConfig _dirConfig = dirConfig.Value;
    private const int ZOOM_LEVEL = 18;
    private const int POINTS_COUNT = 10;
    private const int DISTANCE_BETWEEN_POINTS_M = 100;
    private const double SATELLITE_RADIUS_M = DISTANCE_BETWEEN_POINTS_M * (POINTS_COUNT + 1);

    private string _routeDir = "";
    private string _userRouteDir = "";
    private List<string> _allRouteImages = new();
    private Dictionary<string, int> _currentRouteImages = new();
    private double _currentLat;
    private double _currentLon;
    private CancellationToken _detectToken;
    private int _currentIndex;


    public async Task RunGpsMatching(string userRouteDir, double initialLatitude, double initialLongitude, CancellationToken detectToken = default)
    {
        _routeDir = Path.Combine(SecurityConstants.EXTERNAL_GPS_DENIED_FOLDER, _dirConfig.GpsRouteDirectory);
        _userRouteDir = userRouteDir;

        _allRouteImages = Directory.GetFiles(userRouteDir)
            .OrderBy(x => x).ToList();

        _currentLat = initialLatitude;
        _currentLon = initialLongitude;

        _detectToken = detectToken;
        await StartMatchingRound(0);
    }

    private async Task StartMatchingRound(int startIndex)
    {
        //empty route dir
        if (Directory.Exists(_routeDir))
            Directory.Delete(_routeDir, true);
        Directory.CreateDirectory(_routeDir);

        _currentRouteImages = _allRouteImages
            .Skip(startIndex)
            .Take(POINTS_COUNT)
            .Select((fullName, index) =>
            {
                var filename = Path.GetFileName(fullName);
                File.Copy(Path.Combine(_userRouteDir, filename), Path.Combine(_routeDir, filename));
                return new { Filename = filename, Index = startIndex + index };
            })
            .ToDictionary(x => x.Filename, x => x.Index);

        await satelliteTileDownloader.GetTiles(_currentLat, _currentLon, SATELLITE_RADIUS_M, ZOOM_LEVEL, _detectToken);
        gpsMatcherClient.StartMatching(new StartMatchingEvent
        {
            ImagesCount = POINTS_COUNT,
            Latitude = _currentLat,
            Longitude = _currentLon,
            SatelliteImagesDir = _dirConfig.GpsSatDirectory,
            RouteDir = _dirConfig.GpsRouteDirectory
        });
    }

    public void StopGpsMatching()
    {
        gpsMatcherClient.Stop();
    }

    public Task Handle(GPSMatcherResultEvent result, CancellationToken cancellationToken)
    {
        _currentRouteImages.Remove(result.Image);
        _currentLat = result.Latitude;
        _currentLon = result.Longitude;
        _currentIndex = _currentRouteImages[result.Image];
        return Task.CompletedTask;
    }

    public async Task Handle(GPSMatcherFinishedEvent notification, CancellationToken cancellationToken)
    {
        if (_currentRouteImages.Count == 0 && _currentIndex < _allRouteImages.Count)
            await StartMatchingRound(_currentIndex);
    }
}