{ pkgs, ... }:
{
  # TODO
  # systemd.services.<name>.serviceConfig.{MemoryMax,CPUQuota}
  systemd.services.valheim-server = {
    description = "Valheim dedicated server";
    after = [ "network.target" ];
    wantedBy = [ "multi-user.target" ];
  };

  serviceConfig = {
    Type = "simple";
    User = "valheim";
    Group = "valheim";
    ExecStart = "${pkgs.steamcmd}/bin/steamcmd +login anonymous +force_install_dir /home/valheim/server +app_update 896660 validate +exit && /home/valheim/server/valheim_server.x86_64";
  };

  users.users.valheim = {
    isSystemUser = true;
    group = "valheim";
    home = "/home/valheim";
  };
  users.groups.valheim = {};

  networking.firewall = {
    allowedTCPPorts = [ 7777 2456 ];
    allowedUDPPorts = [ 7777 2457 ];
  };

  services.restic.backups.gameservers = {
    user = "root";
    # TODO: Pick a real backup directory.
    repository = "/backup/gameservers";
    paths = [
      "/var/lib/terraria"
      "/home/valheim/server"
    ];
    timeConfig = {
      OnCalendar = "daily";
    };
  };
}