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

with lib; let

    cfg = config.programs.auto-cpufreq;
    system = "x86_64-linux";
    defaultPackage = inputs.self.packages.${system}.default;
    cfgFilename = "auto-cpufreq.conf";
    cfgFile = format.generate cfgFilename cfg.settings;

    format = pkgs.formats.ini {};

in {

    options.programs.auto-cpufreq = {
        enable = mkEnableOption "Automatic CPU speed & power optimizer for Linux";

        settings = mkOption {
            description = lib.mdDoc ''
            Configuration for `auto-cpufreq`.

            See its [example configuration file] for supported settings.
            [example configuration file]: https://github.com/AdnanHodzic/auto-cpufreq/blob/master/auto-cpufreq.conf-example
            '';

            default = {};
            type = types.submodule { freeformType = format.type; };
        };
    };

    config = mkIf cfg.enable {
        environment.systemPackages = [ defaultPackage ];

        services.auto-cpufreq.enable = true;
        systemd.services.auto-cpufreq = {
            overrideStrategy = "asDropin";
            serviceConfig.ExecStart = lib.mkForce [ 
                "" 
                "${defaultPackage}/bin/auto-cpufreq --daemon --config ${cfgFile}"
            ]; 
        };
    };
}