{ config, lib, pkgs, ... }:

with lib;

let

  cfg = config.services.guix;

in {

  options.services.guix = {
    enable = mkEnableOption "GNU Guix package manager";
  };

  config = mkIf cfg.enable {
    systemd.services.guix-daemon = {
      description = "Build daemon for GNU Guix";

      wantedBy = [ "multi-user.target" ];

      serviceConfig = {
        Restart = "always";
        ExecStart =
          "${pkgs.guix}/bin/guix-daemon --build-users-group=guixbuild";
        Environment = null;
        RemainAfterExit = "yes";
        StandardOutput = "syslog";
        StandardError = "syslog";
        TaskMax = "8192";
      };
    };
    users = {
      extraUsers = lib.attrs.genAttrs (lib.lists.range 1 10) (n: {
        name = "guixbuilder${n}";
        isSystemUser = true;
        extraGroups = [ "guixbuild" ];
        group = "guixbuild";
        description = "Guix build user ${n}";
      });
      extraGroups = { "guixbuild" = { }; };
    };
  };
}