build the backend structure and the fe for the Game

app/Http/Middleware/EnsureRoomParticipant.php

@@ -0,0 +1,50 @@
+<?php
+
+namespace App\Http\Middleware;
+
+use App\Models\Room;
+use Closure;
+use Illuminate\Http\Request;
+use Symfony\Component\HttpFoundation\Response;
+
+class EnsureRoomParticipant
+{
+    /**
+     * Handle an incoming request.
+     *
+     * @param  Closure(Request): (Response)  $next
+     */
+    public function handle(Request $request, Closure $next): Response
+    {
+        $room = $request->route('room');
+
+        if (! $room instanceof Room) {
+            abort(404);
+        }
+
+        $sessionKey = "room_players.{$room->id}";
+        $playerId = $request->session()->get($sessionKey);
+
+        if (! $playerId) {
+            return to_route('room.join', [
+                'join_code' => $room->join_code,
+            ])->withErrors([
+                'join_code' => 'Du musst diesen Raum erst beitreten.',
+            ]);
+        }
+
+        $player = $room->players()->find($playerId);
+
+        if (! $player) {
+            $request->session()->forget($sessionKey);
+
+            return to_route('room.join', [
+                'join_code' => $room->join_code,
+            ]);
+        }
+
+        $request->attributes->set('currentPlayer', $player);
+
+        return $next($request);
+    }
+}