rag/app/Http/Controllers/MessageController.php

<?php

namespace App\Http\Controllers;

use App\Models\Chat;
use App\Services\MessageService;
use Illuminate\Http\Request;

class MessageController extends Controller
{
    /**
     * @throws \Throwable
     */
    public function store(MessageService $service, Chat $chat, Request $request)
    {
        $service->create($chat, $request->string('message'));

        return redirect()->back();
    }
}