{ lib, config, pkgs, inputs, pkgsVersion, ... }:
let cfg = config.custom.hardware.nvidia;
in {
  options.custom.hardware.nvidia = {
    enable = lib.mkEnableOption "Enables nvidia gpus";
    powerLimit = {
      enable = lib.mkEnableOption "Increase GPU power limit";
      wattage = lib.mkOption {
        type = lib.types.int;
        default = 300;
        description = "The power limit to set the GPU to";
      };
    };
    clock = {
      enable = lib.mkEnableOption "Set GPU clocks";
      min = lib.mkOption {
        type = lib.types.int;
        description = "The minimum GPU clock to set";
      };
      max = lib.mkOption {
        type = lib.types.int;
        description = "The maximum GPU clock to set";
      };
      offset = lib.mkOption {
        type = lib.types.int;
        description = "The GPU clock offset to set";
      };
    };
  };

  config = let
    # the option was renamed in unstable
    nvidiaOption = if (pkgsVersion == inputs.nixpkgs-unstable) then {
      hardware.graphics = {
        enable = true;
        enable32Bit = true;
        extraPackages = with pkgs; [ nvidia-vaapi-driver ];
      };
    } else {
      hardware.opengl = {
        enable = true;
        driSupport = true;
        driSupport32Bit = true;
      };
    };
  in lib.mkIf cfg.enable (lib.recursiveUpdate nvidiaOption {
    boot.kernelParams =
      [ "nvidia-drm.fbdev=1" "nvidia.NVreg_PreserveVideoMemoryAllocations=1" ];
    services.xserver.videoDrivers = [ "nvidia" ];
    services.xserver.deviceSection = ''
      Option "Coolbits" "24"
    '';
    hardware.nvidia = {
      # Modesetting is required.
      modesetting.enable = true;
      # Open drivers with gsp stutters in VR - https://github.com/ValveSoftware/SteamVR-for-Linux/issues/631
      gsp.enable = config.hardware.nvidia.open;
      # Nvidia power management. Experimental, and can cause sleep/suspend to fail.
      powerManagement.enable = false;
      # Fine-grained power management. Turns off GPU when not in use.
      # Experimental and only works on modern Nvidia GPUs (Turing or newer).
      powerManagement.finegrained = false;
      # Use the NVidia open source kernel module (not to be confused with the
      # independent third-party "nouveau" open source driver).
      # Support is limited to the Turing and later architectures. Full list of 
      # supported GPUs is at: 
      # https://github.com/NVIDIA/open-gpu-kernel-modules#compatible-gpus 
      # Only available from driver 515.43.04+
      # GSP must be enabled for this to work.
      open = false;
      # Enable the Nvidia settings menu,
      # accessible via `nvidia-settings`.
      nvidiaSettings = true;
      # Optionally, you may need to select the appropriate driver version for your specific GPU.
      package = config.boot.kernelPackages.nvidiaPackages.beta;
        #package = config.boot.kernelPackages.nvidiaPackages.mkDriver {
        #  version = "570.86.16";
        #  sha256_64bit = "sha256-RWPqS7ZUJH9JEAWlfHLGdqrNlavhaR1xMyzs8lJhy9U=";
        #  sha256_aarch64 = "sha256-RiO2njJ+z0DYBo/1DKa9GmAjFgZFfQ1/1Ga+vXG87vA=";
        #  openSha256 = "sha256-DuVNA63+pJ8IB7Tw2gM4HbwlOh1bcDg2AN2mbEU9VPE=";
        #  settingsSha256 = "sha256-9rtqh64TyhDF5fFAYiWl3oDHzKJqyOW3abpcf2iNRT8=";
        #  persistencedSha256 =
        #    "sha256-3mp9X/oV8o2TH9720NnoXROxQ4g98nNee+DucXpQy3w=";
        #};
    };

    environment.systemPackages = with pkgs; [
      vaapiVdpau
      libvdpau-va-gl
      libva
      libva-utils
      (gwe.override { nvidia_x11 = config.hardware.nvidia.package; })
    ];

    systemd.services.nvidiaSetPower = lib.mkIf cfg.powerLimit.enable {
      description =
        "Increase GPU power limit to ${toString cfg.powerLimit.wattage} watts";
      script = "/run/current-system/sw/bin/nvidia-smi -pl=${
          toString cfg.powerLimit.wattage
        }";
      wantedBy = [ "multi-user.target" ];
    };
    systemd.services.nvidiaSetClocks = lib.mkIf cfg.clock.enable {
      description = "Set GPU clocks";
      script =
        "/run/current-system/sw/bin/nvidia-smi -pm 1 && /run/current-system/sw/bin/nvidia-smi -i 0 -lgc ${
          toString cfg.clock.min
        },${toString cfg.clock.max}";
      wantedBy = [ "multi-user.target" ];
      after = [ "display-manager.service" ];
      requires = [ "display-manager.service" ];
      environment.DISPLAY = ":0";
      environment.XAUTHORITY = "/home/kopatz/.Xauthority";
    };
      # doesn't work
      #systemd.user.services.nvidiaSetOffset = lib.mkIf cfg.clock.enable {
      #  description = "Sets gpu offset";
      #  enable = true;
      #  serviceConfig = { Type = "oneshot"; };
      #  script = ''
      #    ${config.hardware.nvidia.package.settings}/bin/nvidia-settings -a "[gpu:0]/GPUGraphicsClockOffsetAllPerformanceLevels=${
      #      toString cfg.clock.offset
      #    }"'';
      #  environment = { DISPLAY = ":0"; };
      #  after = [ "graphical-session.target" ];
      #};
  });
}