nixos/system/services/satisfactory/module.nix

# From: https://gitlab.kuca.cz/tom-kuca/nix-config/-/blob/a11e73470c4f9a151afe67c7fa3a960b838d0d98/modules/nixos/satisfactory.nix
{
  config,
  lib,
  pkgs,
  ...
}:
let
  cfg = config.services.satisfactory-server;
in
{
  options.services.satisfactory-server = {
    enable = lib.mkEnableOption "Satisfactory Dedicated Server";

    steamcmdPackage = lib.mkOption {
      type = lib.types.package;
      default = pkgs.steamcmd;
      defaultText = "pkgs.steamcmd";
      description = ''
        The package implementing SteamCMD
      '';
    };

    dataDir = lib.mkOption {
      type = lib.types.path;
      description = "Directory to store game server";
      default = "/var/lib/satisfactory";
    };

    launchOptions = lib.mkOption {
      type = lib.types.str;
      description = "Launch options to use.";
      default = "";
    };

    openFirewall = lib.mkOption {
      type = lib.types.bool;
      default = false;
      description = ''
        Whether to open ports in the firewall for the server
      '';
    };
  };

  config = lib.mkIf cfg.enable {

    systemd.services.satisfactory-server =
      let
        steamcmd = "${cfg.steamcmdPackage}/bin/steamcmd";
        steam-run = "${pkgs.steam-run}/bin/steam-run";
      in
      {
        description = "Satisfactory Dedicated Server";
        wantedBy = [ "multi-user.target" ];
        after = [ "network.target" ];

        serviceConfig = {
          TimeoutSec = "15min";
          ExecStart = "${steam-run} ${cfg.dataDir}/FactoryServer.sh ${cfg.launchOptions}";
          Restart = "always";
          User = "satisfactory";
          WorkingDirectory = cfg.dataDir;
        };

        preStart = ''
          ${steamcmd} +force_install_dir "${cfg.dataDir}" +login anonymous +app_update 1690800 validate +quit
        '';
      };

    users.users.satisfactory = {
      description = "Satisfactory server service user";
      home = cfg.dataDir;
      createHome = true;
      isSystemUser = true;
      group = "satisfactory";
    };
    users.groups.satisfactory = { };

    networking.firewall =
      let
        ports = [
          7777
          15000
          15777
        ];
      in
      lib.mkIf cfg.openFirewall {
        allowedTCPPorts = ports;
        allowedUDPPorts = ports;
      };
  };
}