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

let
  inherit (config.networking) hostName;
  isClean = inputs.self ? rev;
in
{
  system.autoUpgrade = {
    enable = isClean;
    dates = "hourly";
    flags = [
      "--refresh"
    ];
    flake = "github:ooks-io/nix#${hostName};
  };

# Only run if current config (self) is older than the new one.

  systemd.services.nixos-upgrade = lib.mkIf config.system.autoUpgrade.enable {
    serviceConfig.ExecCondition = lib.getExe (
      pkgs.writeShellScriptBin "check-date" ''
        lastModified() {
          nix flake metadata "$1" --refresh --json | ${lib.getExe pkgs.jq} '.lastModified'
        }
        test "$(lastModified "${config.system.autoUpgrade.flake}")"  -gt "$(lastModified "self")"
      ''
    );
  };
}