pvv-nixos-config/base/services/uptimed.nix

{
  config,
  pkgs,
  lib,
  ...
}:
let
  cfg = config.services.uptimed;
in
{
  options.services.uptimed.settings = lib.mkOption {
    description = "";
    default = { };
    type = lib.types.submodule {
      freeformType = with lib.types; attrsOf (either str (listOf str));
    };
  };

  config = {
    services.uptimed = {
      enable = true;

      settings =
        let
          stateDir = "/var/lib/uptimed";
        in
        {
          PIDFILE = "${stateDir}/pid";
          SENDMAIL = lib.mkDefault "${pkgs.system-sendmail}/bin/sendmail -t";
        };
    };

    systemd.services.uptimed = lib.mkIf (cfg.enable) {
      serviceConfig =
        let
          uptimed = pkgs.uptimed.overrideAttrs (prev: {
            postPatch = ''
              substituteInPlace Makefile.am \
                --replace-fail '$(sysconfdir)/uptimed.conf' '/var/lib/uptimed/uptimed.conf'
              substituteInPlace src/Makefile.am \
                --replace-fail '$(sysconfdir)/uptimed.conf' '/var/lib/uptimed/uptimed.conf'
            '';
          });

        in
        {
          Type = "notify";

          ExecStart = lib.mkForce "${uptimed}/sbin/uptimed -f";

          BindReadOnlyPaths =
            let
              configFile = lib.pipe cfg.settings [
                (lib.mapAttrsToList (
                  k: v: if builtins.isList v then lib.mapConcatStringsSep "\n" (v': "${k}=${v'}") v else "${k}=${v}"
                ))
                (lib.concatStringsSep "\n")
                (pkgs.writeText "uptimed.conf")
              ];
            in
            [
              "${configFile}:/var/lib/uptimed/uptimed.conf"
            ];
        };
    };
  };
}