{ config, lib, pkgs, modulesPath, ... }:
let
  inherit (lib) mkEnableOption mkIf;
  inherit (lib.my-namespace) disabled enabled;
  cfg = config.my-namespace.hardware.graphics-nvidia-specializations;
in
{
  options.my-namespace.hardware.graphics-nvidia-specializations = {
    enable = mkEnableOption "Enable nvidia";
  };
  options.nvidia-sync.enable = lib.mkEnableOption "Enable NVIDIA prime sync mode";
  options.nvidia-offload.enable = lib.mkEnableOption "Enable NVIDIA prime sync mode";

  config = {
    specialisation."NVIDIA-SYNC".configuration = {
      system.nixos.tags = [ "with-nvidia-sync" ];
      nvidia-sync.enable = true;
    };

    specialisation."NVIDIA-OFFLOAD".configuration = {
      system.nixos.tags = [ "with-nvidia-offload" ];
      nvidia-offload.enable = true;
    };

    services.xserver.videoDrivers = [ "nvidia" "amdgpu" ];
    hardware.graphics = {
      extraPackages = with pkgs; [ nvidia-vaapi-driver ];
    };
    boot.kernelParams = [ 
      "nvidia.NVreg_PreserveVideoMemoryAllocations=1"
      "nvidia-drm.fbdev=0"
      "nvidia-drm.modeset=0"
      "amdgpu.modeset=1"
    ];
    boot.initrd.kernelModules = [
      # "amdgpu"
      "nvidia"
      "nvidia-drm"
      "nvidia_drm"
      "nvidia-uvm"
      "nvidia_uvm"
      # "nvidia-modeset"
      # "i2c-nvidia_gpu"    
    ];

    hardware.nvidia = {
      modesetting.enable = true;

      # 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+
      # Currently alpha-quality/buggy, so false is currently the recommended setting.
      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.production;

      prime = {
        amdgpuBusId = "PCI:50:0:0";
        nvidiaBusId = "PCI:1:0:0";
      } // lib.optionalAttrs config.nvidia-sync.enable {
        sync.enable = false;
      } // lib.optionalAttrs (config.nvidia-offload.enable) {
        offload = {
          enable = true;
          enableOffloadCmd = true;
        };
      };
    };
    services.xserver.config = lib.mkAfter ''
      Section "ServerLayout"
        Identifier "layout"
        Screen 0 "amdgpu"
        Inactive "nvidia"
        Option "AllowNVIDIAGPUScreens"
        Option "AllowEmptyInitialConfiguration" "True"
      EndSection

      Section "Device"
        Identifier "nvidia"
        Driver "nvidia"
        BusID "PCI:01:0:0"
        Option "AllowEmptyInitialConfiguration" "True"
      EndSection

      Section "Screen"
        Identifier "nvidia"
        Device "nvidia"
        Option "AllowEmptyInitialConfiguration" "True"
      EndSection

      Section "Device"
        Identifier "amdgpu"
        Driver "amdgpu"
        BusID "PCI:50:0:0"
        #Option "AllowNVIDIAGPUScreens"
        #Option "AllowEmptyInitialConfiguration" "True"
      EndSection

      Section "Screen"
        Identifier "amdgpu"
        Device "amdgpu"
        #Option "AllowEmptyInitialConfiguration" "True"
      EndSection
    '';
    # services.xserver.config = lib.mkForce ''
    #   Section "ServerLayout"
    #     Identifier "layout"
    #     Screen 0 "amdgpu"
    #     Inactive "nvidia"
    #     Option "AllowNVIDIAGPUScreens"
    #   EndSection

    #   Section "Device"
    #     Identifier "nvidia"
    #     Driver "nvidia"
    #     BusID "PCI:01:0:0"
    #   EndSection

    #   Section "Screen"
    #     Identifier "nvidia"
    #     Device "nvidia"
    #   EndSection

    #   Section "Device"
    #     Identifier "amdgpu"
    #     Driver "amdgpu"
    #     BusID "PCI:50:0:0"
    #   EndSection

    #   Section "Screen"
    #     Identifier "amdgpu"
    #     Device "amdgpu"
    #   EndSection
    # '';
  };
}