satellite-provider/SatelliteProvider.DataAccess/Repositories/TileRepository.cs

using System.Diagnostics;
using Dapper;
using Microsoft.Extensions.Logging;
using Npgsql;
using SatelliteProvider.DataAccess.Models;

namespace SatelliteProvider.DataAccess.Repositories;

public class TileRepository : ITileRepository
{
    private const int SlowQueryThresholdMs = 500;

    private const string ColumnList = @"id, tile_zoom as TileZoom, tile_x as TileX, tile_y as TileY,
                   latitude, longitude,
                   tile_size_meters as TileSizeMeters, tile_size_pixels as TileSizePixels,
                   image_type as ImageType, maps_version as MapsVersion, version,
                   file_path as FilePath, created_at as CreatedAt, updated_at as UpdatedAt";

    private readonly string _connectionString;
    private readonly ILogger<TileRepository> _logger;

    public TileRepository(string connectionString, ILogger<TileRepository> logger)
    {
        _connectionString = connectionString;
        _logger = logger;
    }

    public async Task<TileEntity?> GetByIdAsync(Guid id)
    {
        using var connection = new NpgsqlConnection(_connectionString);
        const string sql = $@"
            SELECT {ColumnList}
            FROM tiles
            WHERE id = @Id";

        return await connection.QuerySingleOrDefaultAsync<TileEntity>(sql, new { Id = id });
    }

    public async Task<TileEntity?> GetByTileCoordinatesAsync(int tileZoom, int tileX, int tileY)
    {
        using var connection = new NpgsqlConnection(_connectionString);
        const string sql = $@"
            SELECT {ColumnList}
            FROM tiles
            WHERE tile_zoom = @TileZoom AND tile_x = @TileX AND tile_y = @TileY
            ORDER BY updated_at DESC
            LIMIT 1";

        return await connection.QuerySingleOrDefaultAsync<TileEntity>(sql, new { TileZoom = tileZoom, TileX = tileX, TileY = tileY });
    }

    public async Task<IEnumerable<TileEntity>> GetTilesByRegionAsync(double latitude, double longitude, double sizeMeters, int zoomLevel)
    {
        using var connection = new NpgsqlConnection(_connectionString);

        const double EARTH_CIRCUMFERENCE_METERS = 40075016.686;
        const int TILE_SIZE_PIXELS = 256;
        var latRad = latitude * Math.PI / 180.0;
        var metersPerPixel = (EARTH_CIRCUMFERENCE_METERS * Math.Cos(latRad)) / (Math.Pow(2, zoomLevel) * TILE_SIZE_PIXELS);
        var tileSizeMeters = metersPerPixel * TILE_SIZE_PIXELS;

        var expandedSizeMeters = sizeMeters + (tileSizeMeters * 2);

        var latRange = expandedSizeMeters / 111000.0;
        var lonRange = expandedSizeMeters / (111000.0 * Math.Cos(latitude * Math.PI / 180.0));

        const string sql = $@"
            SELECT {ColumnList}
            FROM tiles
            WHERE latitude BETWEEN @MinLat AND @MaxLat
              AND longitude BETWEEN @MinLon AND @MaxLon
              AND tile_zoom = @TileZoom
            ORDER BY latitude DESC, longitude ASC, updated_at DESC";

        var stopwatch = Stopwatch.StartNew();
        var tiles = await connection.QueryAsync<TileEntity>(sql, new
        {
            MinLat = latitude - latRange / 2,
            MaxLat = latitude + latRange / 2,
            MinLon = longitude - lonRange / 2,
            MaxLon = longitude + lonRange / 2,
            TileZoom = zoomLevel
        });
        stopwatch.Stop();

        if (stopwatch.ElapsedMilliseconds > SlowQueryThresholdMs)
        {
            _logger.LogWarning(
                "Slow GetTilesByRegionAsync: {ElapsedMs} ms (threshold {ThresholdMs} ms) for lat={Latitude}, lon={Longitude}, sizeMeters={SizeMeters}, zoom={ZoomLevel}",
                stopwatch.ElapsedMilliseconds, SlowQueryThresholdMs, latitude, longitude, sizeMeters, zoomLevel);
        }

        return tiles;
    }

    public async Task<Guid> InsertAsync(TileEntity tile)
    {
        using var connection = new NpgsqlConnection(_connectionString);
        const string sql = @"
            INSERT INTO tiles (id, tile_zoom, tile_x, tile_y, latitude, longitude, tile_size_meters, 
                             tile_size_pixels, image_type, maps_version, version, file_path, 
                             created_at, updated_at)
            VALUES (@Id, @TileZoom, @TileX, @TileY, @Latitude, @Longitude, @TileSizeMeters, 
                    @TileSizePixels, @ImageType, @MapsVersion, @Version, @FilePath, 
                    @CreatedAt, @UpdatedAt)
            ON CONFLICT (latitude, longitude, tile_zoom, tile_size_meters) 
            DO UPDATE SET 
                file_path = EXCLUDED.file_path,
                tile_x = EXCLUDED.tile_x,
                tile_y = EXCLUDED.tile_y,
                updated_at = EXCLUDED.updated_at
            RETURNING id";

        return await connection.ExecuteScalarAsync<Guid>(sql, tile);
    }

    public async Task<int> UpdateAsync(TileEntity tile)
    {
        using var connection = new NpgsqlConnection(_connectionString);
        const string sql = @"
            UPDATE tiles 
            SET tile_zoom = @TileZoom,
                tile_x = @TileX,
                tile_y = @TileY,
                latitude = @Latitude, 
                longitude = @Longitude,
                tile_size_meters = @TileSizeMeters,
                tile_size_pixels = @TileSizePixels,
                image_type = @ImageType,
                maps_version = @MapsVersion,
                version = @Version,
                file_path = @FilePath,
                updated_at = @UpdatedAt
            WHERE id = @Id";

        return await connection.ExecuteAsync(sql, tile);
    }

    public async Task<int> DeleteAsync(Guid id)
    {
        using var connection = new NpgsqlConnection(_connectionString);
        const string sql = "DELETE FROM tiles WHERE id = @Id";
        return await connection.ExecuteAsync(sql, new { Id = id });
    }
}