nix/config/Powersave.nix

{
  lib,
  config,
  pkgs,
  ...
}:
let
  cfg = config.module.powersave;

  script = pkgs.writeShellScriptBin "powersave" ''
    function toggle() {
      if status; then
        echo ${cfg.cpu.boost.disableCmd} > ${cfg.cpu.boost.controlFile}
      else
        echo ${cfg.cpu.boost.enableCmd} > ${cfg.cpu.boost.controlFile}
      fi

      pkill -RTMIN+5 waybar
      true
    }

    function widget() {
      status && printf '​' || printf '󰓅'
    }

    function status() {
      local current=$(cat ${cfg.cpu.boost.controlFile})
      local enabled="${cfg.cpu.boost.enableCmd}"

      [[ "''${current}" = "''${enabled}" ]]
    }

    ''${@}
  '';
in
{
  config = lib.mkIf cfg.enable {
    environment.systemPackages = [ script ];
    systemd = {
      services.powersave-cpu = {
        enable = true;
        description = "disable CPU Boost";
        wantedBy = [ "multi-user.target" ];
        serviceConfig = {
          Type = "simple";
          RemainAfterExit = "yes";
          ExecStart = "${lib.getExe pkgs.bash} -c 'echo ${cfg.cpu.boost.enableCmd} > ${cfg.cpu.boost.controlFile}'";
          ExecStop = "${lib.getExe pkgs.bash} -c 'echo ${cfg.cpu.boost.disableCmd} > ${cfg.cpu.boost.controlFile}'";
        };
      };

      # HACK: Allow user access.
      tmpfiles.rules = [ "z ${cfg.cpu.boost.controlFile} 0777 - - - -" ];
    };
  };
}