tiles are cached and reused properly

SatelliteProvider.Services/GoogleMapsDownloaderV2.cs

@@ -75,7 +75,7 @@ public class GoogleMapsDownloaderV2
         Directory.CreateDirectory(_tilesDirectory);
 
         var timestamp = DateTime.UtcNow.ToString("yyyyMMddHHmmss");
-        var fileName = $"raw_tile_{zoomLevel}_{tileX}_{tileY}_{timestamp}.jpg";
+        var fileName = $"tile_{zoomLevel}_{tileX}_{tileY}_{timestamp}.jpg";
         var filePath = Path.Combine(_tilesDirectory, fileName);
 
         using var httpClient = _httpClientFactory.CreateClient();
@@ -111,7 +111,12 @@ public class GoogleMapsDownloaderV2
         return metersPerPixel * TILE_SIZE_PIXELS;
     }
 
-    public async Task<List<DownloadedTileInfoV2>> GetTilesWithMetadataAsync(GeoPoint centerGeoPoint, double radiusM, int zoomLevel, CancellationToken token = default)
+    public async Task<List<DownloadedTileInfoV2>> GetTilesWithMetadataAsync(
+        GeoPoint centerGeoPoint, 
+        double radiusM, 
+        int zoomLevel, 
+        IEnumerable<DataAccess.Models.TileEntity> existingTiles,
+        CancellationToken token = default)
     {
         if (!ALLOWED_ZOOM_LEVELS.Contains(zoomLevel))
         {
@@ -123,12 +128,12 @@ public class GoogleMapsDownloaderV2
         var (xMin, yMin) = GeoUtils.WorldToTilePos(new GeoPoint(latMax, lonMin), zoomLevel);
         var (xMax, yMax) = GeoUtils.WorldToTilePos(new GeoPoint(latMin, lonMax), zoomLevel);
 
-        _logger.LogInformation("Downloading tiles for region: center=({Lat}, {Lon}), radius={Radius}m, zoom={Zoom}", 
+        _logger.LogInformation("Checking tiles for region: center=({Lat}, {Lon}), radius={Radius}m, zoom={Zoom}", 
             centerGeoPoint.Lat, centerGeoPoint.Lon, radiusM, zoomLevel);
         _logger.LogInformation("Tile range: X=[{XMin}, {XMax}], Y=[{YMin}, {YMax}]", xMin, xMax, yMin, yMax);
 
-        var sessionToken = await GetSessionToken();
         var downloadedTiles = new List<DownloadedTileInfoV2>();
+        int skippedCount = 0;
 
         for (var y = yMin; y <= yMax; y++)
         {
@@ -137,8 +142,24 @@ public class GoogleMapsDownloaderV2
                 token.ThrowIfCancellationRequested();
 
                 var tileCenter = GeoUtils.TileToWorldPos(x, y, zoomLevel);
+                
+                var existingTile = existingTiles.FirstOrDefault(t =>
+                    Math.Abs(t.Latitude - tileCenter.Lat) < 0.0001 &&
+                    Math.Abs(t.Longitude - tileCenter.Lon) < 0.0001 &&
+                    t.ZoomLevel == zoomLevel);
+
+                if (existingTile != null)
+                {
+                    skippedCount++;
+                    _logger.LogInformation("Skipping tile ({X}, {Y}) - already exists at {FilePath}", x, y, existingTile.FilePath);
+                    continue;
+                }
+
                 var tileSizeMeters = CalculateTileSizeInMeters(zoomLevel, tileCenter.Lat);
 
+                try
+                {
+                    var sessionToken = await GetSessionToken();
                     var server = (x + y) % 4;
                     var url = string.Format(TILE_URL_TEMPLATE, server, x, y, zoomLevel, sessionToken);
 
@@ -148,8 +169,6 @@ public class GoogleMapsDownloaderV2
                     var fileName = $"tile_{zoomLevel}_{x}_{y}_{timestamp}.jpg";
                     var filePath = Path.Combine(_tilesDirectory, fileName);
 
-                try
-                {
                     using var httpClient = _httpClientFactory.CreateClient();
                     httpClient.DefaultRequestHeaders.UserAgent.ParseAdd(USER_AGENT);
 
@@ -173,7 +192,7 @@ public class GoogleMapsDownloaderV2
             }
         }
 
-        _logger.LogInformation("Downloaded {Count} tiles for region", downloadedTiles.Count);
+        _logger.LogInformation("Downloaded {Count} new tiles, skipped {Skipped} existing tiles", downloadedTiles.Count, skippedCount);
         return downloadedTiles;
     }
 }

SatelliteProvider.Services/TileService.cs

@@ -46,51 +46,26 @@ public class TileService : ITileService
         }
         
         var centerPoint = new GeoPoint(latitude, longitude);
-        var downloadedTiles = await _downloader.GetTilesWithMetadataAsync(centerPoint, sizeMeters / 2, zoomLevel, cancellationToken);
+        var downloadedTiles = await _downloader.GetTilesWithMetadataAsync(
+            centerPoint, 
+            sizeMeters / 2, 
+            zoomLevel, 
+            existingTilesList,
+            cancellationToken);
         
-        _logger.LogInformation("Downloaded {Count} tiles from Google:", downloadedTiles.Count);
-        foreach (var dt in downloadedTiles)
-        {
-            _logger.LogInformation("  Downloaded: Lat={Lat:F12}, Lon={Lon:F12}, Zoom={Zoom}", dt.CenterLatitude, dt.CenterLongitude, dt.ZoomLevel);
-        }
+        _logger.LogInformation("Downloaded {Count} new tiles from Google", downloadedTiles.Count);
         
         var result = new List<TileMetadata>();
-        int reusedCount = 0;
-        int downloadedCount = 0;
+        int reusedCount = existingTilesList.Count;
+        int downloadedCount = downloadedTiles.Count;
+        
+        foreach (var existingTile in existingTilesList)
+        {
+            result.Add(MapToMetadata(existingTile));
+        }
         
         foreach (var downloadedTile in downloadedTiles)
         {
-            var existingTile = existingTilesList.FirstOrDefault(t =>
-                Math.Abs(t.Latitude - downloadedTile.CenterLatitude) < 0.0001 &&
-                Math.Abs(t.Longitude - downloadedTile.CenterLongitude) < 0.0001 &&
-                t.ZoomLevel == downloadedTile.ZoomLevel);
-
-            if (existingTile != null)
-            {
-                reusedCount++;
-                _logger.LogInformation("REUSED tile at ({Lat:F12}, {Lon:F12}) - matched DB tile ID {Id}", downloadedTile.CenterLatitude, downloadedTile.CenterLongitude, existingTile.Id);
-                result.Add(MapToMetadata(existingTile));
-            }
-            else
-            {
-                downloadedCount++;
-                _logger.LogInformation("NEW tile needed at ({Lat:F12}, {Lon:F12}) - no match in DB", downloadedTile.CenterLatitude, downloadedTile.CenterLongitude);
-                
-                var closestTile = existingTilesList
-                    .Select(t => new { 
-                        Tile = t, 
-                        LatDiff = Math.Abs(t.Latitude - downloadedTile.CenterLatitude),
-                        LonDiff = Math.Abs(t.Longitude - downloadedTile.CenterLongitude)
-                    })
-                    .OrderBy(x => x.LatDiff + x.LonDiff)
-                    .FirstOrDefault();
-                
-                if (closestTile != null)
-                {
-                    _logger.LogInformation("  Closest DB tile: Lat={Lat:F12} (diff={LatDiff:F12}), Lon={Lon:F12} (diff={LonDiff:F12})", 
-                        closestTile.Tile.Latitude, closestTile.LatDiff, closestTile.Tile.Longitude, closestTile.LonDiff);
-                }
-                
             var now = DateTime.UtcNow;
             var tileEntity = new TileEntity
             {
@@ -112,7 +87,6 @@ public class TileService : ITileService
             _logger.LogInformation("Saved new tile {Id} at ({Lat:F12}, {Lon:F12}) version {Version}", tileEntity.Id, tileEntity.Latitude, tileEntity.Longitude, currentVersion);
             result.Add(MapToMetadata(tileEntity));
         }
-        }
         
         _logger.LogInformation("Tile processing summary: {Reused} reused, {Downloaded} new", reusedCount, downloadedCount);