{ hostRegistry, config, lib, pkgs, modulesPath, ... }:

{
  c3d2 = {
    isInHq = true;
    mergeHostsFile = true;
    hq.interface = "eth0";
    hq.statistics.enable = true;
    audioServer.enable = true;
    k-ot.enable = true;
    # TODO: move back to radiobert with the HW
    pi-sensors = if true then [] else [ {
      type = "dht22";
      pin = 17;
      location = "lang";
    } {
      type = "dht22";
      pin = 23;
      location = "kurz";
    } ];
  };

  hardware.enableRedistributableFirmware = true;
  powerManagement.cpuFreqGovernor = lib.mkDefault "performance";

  nixpkgs.config.packageOverrides = pkgs: {
    makeModulesClosure = x:
      # prevent kernel install fail due to missing modules
      pkgs.makeModulesClosure (x // { allowMissing = true; });
  };

  boot = {
    loader = {
      raspberryPi = {
        enable = true;
        version = 4;
        firmwareConfig = ''
          gpu_mem=256
          dtparam=audio=on
        '';
      };
    };

    kernelParams = lib.mkForce [
      "snd_bcm2835.enable_headphones=1"
      # don't let sd-image-aarch64.nix setup serial console as it breaks bluetooth.
      "console=tty0"
      # allow GPIO access
      "iomem=relaxed" "strict-devmem=0"
      # booting sometimes fails with an oops in the ethernet driver. reboot after 5s
      "panic=5" "oops=panic"
    ];

    tmpOnTmpfs = true;
    tmpOnTmpfsSize = "80%";
  };
  # hardware.raspberry-pi."4" = {
  #   fkms-3d.enable = true;
  # };
  fileSystems."/" = {
    device = "${hostRegistry.hosts.nfsroot.ip4}:/var/lib/nfsroot/dacbert";
    fsType = "nfs";
    options = [ "nfsvers=3" "proto=tcp" "nolock" "hard" "async" "rw" ];
  };

  networking = {
    hostName = "dacbert"; # Define your hostname.
    useDHCP = false;
    interfaces.eth0.useDHCP = true;
    firewall.enable = false;
  };

  nix = {
    buildCores = 4;
    maxJobs = 1;
    trustedUsers = [ "client" ];
    extraOptions = ''
      builders-use-substitutes = true
      extra-platforms = armv6l-linux,armv7l-linux
    '';
    daemonCPUSchedPolicy = "idle";
    daemonIOSchedClass = "idle";
  };

  environment.systemPackages = with pkgs; [
    libraspberrypi
    raspberrypi-eeprom
    vim
    wget
    libva-utils
    mpv
    vlc
    yt-dlp
    ncpamixer
    pulseaudio # required for pactl
    chromium
    firefox
    pavucontrol
    glxinfo
    # tracer-game
    bevy_julia
    bevy_mandelbrot
    allcolors
  ];

  programs.tmux.enable = true;

  security.sudo = {
    enable = true;
    wheelNeedsPassword = false;
  };

  # Select internationalisation properties.
  console = {
    font = "${pkgs.terminus_font}/share/consolefonts/ter-u28n.psf.gz";
    keyMap = "de";
  };

  services = {
    # Do not log to flash:
    journald.extraConfig = ''
      Storage=volatile
    '';

    openssh = {
      enable = true;
    };

    xserver = {
      enable = true;
      layout = "de";
      xkbOptions = "eurosign:e";
    };
  };

  services.xserver = {
    desktopManager = {
      gnome.enable = true;
    };

    displayManager = {
      gdm = {
        enable = true;
        wayland = true;
      };
      autoLogin = {
        enable = true;
        user = "k-ot";
      };
      defaultSession = "gnome";
    };
  };

  systemd = {
    services.nix-daemon.serviceConfig = {
      LimitNOFILE = lib.mkForce 8192;
      CPUWeight = 5;
      MemoryHigh = "4G";
      MemoryMax = "6G";
      MemorySwapMax = "0";
  };

    # replaced by gnome-sharing
    # user.services.wayvnc = {
    #   description = "Wayland VNC server";
    #   wantedBy = [ "graphical-session.target" ];
    #   partOf = [ "graphical-session.target" ];
    #   serviceConfig = {
    #     ExecStart = ''
    #       ${pkgs.wayvnc}/bin/wayvnc 0.0.0.0
    #     '';
    #     RestartSec = 3;
    #     Restart = "always";
    #   };
    # };
  };

  system.stateVersion = "21.05"; # Did you read the comment?
}