tanks can spawn and get rendered

TanksServer/Services/SpawnQueue.cs

@@ -0,0 +1,51 @@
+using System.Collections.Concurrent;
+using TanksServer.Models;
+
+namespace TanksServer.Services;
+
+internal sealed class SpawnQueue(TankManager tanks, MapService map) : ITickStep
+{
+    private readonly ConcurrentQueue<Player> _playersToSpawn = new();
+
+    public Task TickAsync()
+    {
+        while (_playersToSpawn.TryDequeue(out var player))
+        {
+            var tank = new Tank(player, ChooseSpawnPosition())
+            {
+                Rotation = Random.Shared.Next(0, 16)
+            };
+            tanks.Add(tank);
+        }
+
+        return Task.CompletedTask;
+    }
+
+    private PixelPosition ChooseSpawnPosition()
+    {
+        List<TilePosition> candidates = new();
+        
+        for (var x = 0; x < MapService.TilesPerRow; x++)
+        for (var y = 0; y < MapService.TilesPerColumn; y++)
+        {
+            var tile = new TilePosition(x, y);
+
+            if (map.IsCurrentlyWall(tile))
+                continue;
+            
+            // TODO: check tanks
+            candidates.Add(tile);
+        }
+
+        var chosenTile = candidates[Random.Shared.Next(candidates.Count)];
+        return new PixelPosition(
+            chosenTile.X * MapService.TileSize,
+            chosenTile.Y * MapService.TileSize
+        );
+    }
+
+    public void SpawnTankForPlayer(Player player)
+    {
+        _playersToSpawn.Enqueue(player);
+    }
+}