misc_pterodactyl-panel/app/Services/Users/UserDeletionService.php

<?php

namespace Pterodactyl\Services\Users;

use Pterodactyl\Models\User;
use Pterodactyl\Exceptions\DisplayException;
use Illuminate\Contracts\Translation\Translator;
use Pterodactyl\Contracts\Repository\ServerRepositoryInterface;

class UserDeletionService
{
    /**
     * UserDeletionService constructor.
     */
    public function __construct(
        protected ServerRepositoryInterface $serverRepository,
        protected Translator $translator
    ) {
    }

    /**
     * Delete a user from the panel only if they have no servers attached to their account.
     *
     * @throws DisplayException
     */
    public function handle(int|User $user): ?bool
    {
        if (is_int($user)) {
            $user = User::query()->findOrFail($user);
        }

        $servers = $this->serverRepository->setColumns('id')->findCountWhere([['owner_id', '=', $user->id]]);
        if ($servers > 0) {
            throw new DisplayException($this->translator->get('admin/user.exceptions.user_has_servers'));
        }

        return $user->delete();
    }
}