move backend to subfolder

tanks-backend/TanksServer/Interactivity/PlayerServer.cs

@@ -0,0 +1,42 @@
+using System.Diagnostics.CodeAnalysis;
+using TanksServer.GameLogic;
+
+namespace TanksServer.Interactivity;
+
+internal sealed class PlayerServer(ILogger<PlayerServer> logger, TankSpawnQueue tankSpawnQueue)
+{
+    private readonly ConcurrentDictionary<string, Player> _players = new();
+
+    public Player? GetOrAdd(string name, Guid id)
+    {
+        Player AddAndSpawn()
+        {
+            var player = new Player(name, id);
+            tankSpawnQueue.EnqueueForImmediateSpawn(player);
+            return player;
+        }
+
+        var player = _players.GetOrAdd(name, _ => AddAndSpawn());
+        if (player.Id != id)
+            return null;
+
+        logger.LogInformation("player {} (re)joined", player.Id);
+        return player;
+    }
+
+    public bool TryGet(Guid? playerId, [MaybeNullWhen(false)] out Player foundPlayer)
+    {
+        foreach (var player in _players.Values)
+        {
+            if (player.Id != playerId)
+                continue;
+            foundPlayer = player;
+            return true;
+        }
+
+        foundPlayer = null;
+        return false;
+    }
+
+    public IEnumerable<Player> GetAll() => _players.Values;
+}