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

{
  imports = let ifExists = p: if builtins.pathExists p then p else {}; in [
    ./cachix.nix # update with `cachix use --mode nixos -d . FOOBAR`
    ./secrets
    ./profiles/locale-no.nix
    ./profiles/upgrade-diff.nix
    ./profiles/lix.nix
    # results of 'nixos-generate-config'
    # nice to have if i just dump this flake into /etc/nixos on a clean install
    (ifExists ./configuration.nix )
    (ifExists ./hardware-configuration.nix )

    # TODO: move somewhere smart
    {
      options.virtualisation.isVmVariant = lib.mkOption {
        type = lib.types.bool;
        default = false;
      };
      config.virtualisation.vmVariant = {
        virtualisation.isVmVariant = true;
      };
    }
  ];

  nixpkgs.overlays = [
    (import ./overlays/wl-clipboard-timeout.nix)
  ];

  nixpkgs.config.permittedInsecurePackages = [
    pkgs.pulsar.name
    pkgs.zotero.name
    pkgs.gitea.name
  ];

  environment.systemPackages = with pkgs; [
    ddrescue
    gptfdisk
    ms-sys
    nvme-cli
    parted
    pciutils
    smartmontools
    testdisk
    usbutils
  ] ++ lib.optionals (builtins.elem config.nixpkgs.system [ "x86_64-linux" "aarch64_linux"]) [
    cage
    weston
  ];

  # TODO: selectively whitelist
  nixpkgs.config.allowUnfree = true;
  nixpkgs.config.allowUnfreePredicate = pkg: true;
  nixpkgs.config.nonfreeLicensing = true; # used by ffmpeg

  hardware.enableRedistributableFirmware = true;

  boot.initrd.systemd.enable = true; # systemd manages initfs boot, systemd-analyse can see what happened
  # https://discourse.nixos.org/t/what-to-do-with-a-full-boot-partition/2049
  # raise to 15 if auto upgrading
  boot.loader.grub.configurationLimit = lib.mkDefault 5;
  boot.loader.systemd-boot.configurationLimit = lib.mkDefault 5;
  boot.loader.generic-extlinux-compatible.configurationLimit = lib.mkDefault 5;

  networking.firewall.enable = true; # default
  #networking.nftables.enable = true; # wirewall backend, instead of iptables, breaks docker which uses iptables
  #networking.firewall.allowPing = false;
  #networking.networkmanager.wifi.backend = "iwd"; # default is wpa_supplicant, iwd doesn't support eduroam

  #system.switch.enable = false;
  #system.switch.enableNg = true; # rewritten in rust

  sops.secrets.nix-access-tokens = {};
  sops.secrets.nix-access-tokens-all.mode = "0440";
  sops.secrets.nix-access-tokens-all.group = config.users.groups."keys".name;
  nix.extraOptions = ''
    !include ${config.sops.secrets.nix-access-tokens.path}
    !include ${config.sops.secrets.nix-access-tokens-all.path}
  '';

  nix.settings.experimental-features = [
    "nix-command"
    "flakes"
    /* "pipe-operator" # not supported on lix 2.91 */
  ];
  #nix.settings.allowed-users = [ "@builders" ]; # TODO: this
  nix.settings.allowed-users = [ "root" "pbsds" "@wheel" ]; # default is [ "*" ]
  nix.settings.trusted-users = [ "root" "pbsds" "@wheel" ];
  nix.settings.keep-derivations = true; # keep .drv in store, great with nix-diff
  nix.settings.auto-optimise-store = true; # deduplicate with hardlinks, expensive. Alternative: nix-store --optimise
  nix.settings.max-silent-time = 3600;
  #nix.settings.keep-failed = true; # fills up $TMPDIR
  nix.settings.log-lines = 35;
  #nix.optimize.automatic = true; # periodic optimization
  nix.gc.automatic = true;
  nix.gc.dates     = "weekly";
  nix.gc.options   = lib.mkIf config.system.autoUpgrade.enable "--delete-older-than 15d";
  nix.settings.min-free =  3 * 1024 * 1024 * 1024; # starts cg
  nix.settings.max-free = 20 * 1024 * 1024 * 1024; # condition to end gc triggered by min-free

  services.thermald.enable = lib.all (x: x) [
    (config.nixpkgs.system == "x86_64-linux")
    (!config.boot.isContainer or false)
  ];

  # no acme in VM mode:
  virtualisation.vmVariant = {
    security.acme.defaults.server = "https://127.0.0.1";
    security.acme.preliminarySelfsigned = true;
  };

  # set VM root password in VM mode
  virtualisation.vmVariant = {
    users.users.root.initialPassword = "root";
  };

  # fix VM networking, disable static IPs
  virtualisation.vmVariant = {
    networking.interfaces = lib.mkForce {};
    networking.defaultGateway = lib.mkForce null;
    networking.nameservers = lib.mkForce [];
    networking.networkmanager.enable = lib.mkForce false;
    networking.useDHCP = lib.mkForce true;
  };

  # System fonts
  # Nice to have when X-forwading on headless machines
  fonts.fontDir.enable = true; # creates /run/current-system/sw/share/X11/fonts
  fonts.enableDefaultPackages = true; # dejavu, freefont, gyre, liberation, unifont, noto-fonts-emoji
  fonts.packages = with pkgs; [
    noto-fonts # includes Cousine
    noto-fonts-cjk-sans
    noto-fonts-cjk-serif
    noto-fonts-emoji
    noto-fonts-extra
  ];
}