reposition tanks on map switch, rework map logic

tanks-backend/TanksServer/GameLogic/EmptyTileFinder.cs

@@ -0,0 +1,32 @@
+namespace TanksServer.GameLogic;
+
+internal sealed class EmptyTileFinder(
+    MapEntityManager entityManager,
+    MapService mapService
+)
+{
+    public TilePosition ChooseEmptyTile()
+    {
+        var maxMinDistance = 0d;
+        TilePosition spawnTile = default;
+        for (ushort x = 1; x < MapService.TilesPerRow - 1; x++)
+        for (ushort y = 1; y < MapService.TilesPerColumn - 1; y++)
+        {
+            var tile = new TilePosition(x, y);
+            if (mapService.Current.IsWall(tile))
+                continue;
+
+            var tilePixelCenter = tile.GetCenter().ToFloatPosition();
+            var minDistance = entityManager.AllEntities
+                .Select(entity => entity.Position.Distance(tilePixelCenter))
+                .Aggregate(double.MaxValue, Math.Min);
+            if (minDistance <= maxMinDistance)
+                continue;
+
+            maxMinDistance = minDistance;
+            spawnTile = tile;
+        }
+
+        return spawnTile;
+    }
+}