{ pkgs, lib, config, ... }: let
  cfg = config.mods.server.sync;

in {
  options.mods.server.sync = {
    enable = lib.mkEnableOption {
      default = false;
      description = "enables synchronisation related servers";
    };
    address = lib.mkOption {
      default = "127.0.0.1";
    };
    port = lib.mkOption {
      default = "8384";
    };
  };

  config = lib.mkIf cfg.enable {
    services.syncthing.enable = true;
    networking.firewall.allowedTCPPorts = [ 8384 22000 ];
    networking.firewall.allowedUDPPorts = [ 22000 21027 ];
    services.syncthing.guiAddress =
      "${cfg.address}:${cfg.port}";
  };
}