{
  lib, pkgs
}:

config: {
  userName
, hostName
, wireless ? false
, wifiInterface ? ""
, overlays ? []
, hardwareImports ? [ "generic" ]
, programImports ? []
, extraImports ? []
, isVM ? false
, fileSystems
, swapDevices ? []
, extraPackages ? pkgs: []
, extraOptions ? old: {}
}:

let
  overlaysSet = import ../overlays { pkgs = pkgs; lib = lib; };
  network = import ./network.nix;
  home-manager = builtins.fetchGit {
    url = "https://github.com/nix-community/home-manager.git";
    rev = "35a24648d155843a4d162de98c17b1afd5db51e4";
    ref = "release-21.05";
  };
  baseConfig = {
    # Install home-manager
    imports = [
      "${home-manager}/nixos"
      ./users # For system.singleUser
      (./users + "/${userName}.nix")
    ] ++ (map (item: ./programs + "/${item}") programImports)
      ++ (map (item: ./hardware + "/${item}.nix") hardwareImports)
      ++ lib.optional wireless ./hardware/wifi.nix
      ++ (map (item: ./. + "/${item}") extraImports);
    home-manager.useGlobalPkgs = true;

    nixpkgs.overlays = (map (item: lib.getAttr item overlaysSet) overlays);
    
    time.timeZone = "Europe/Berlin";
    networking = {
      useDHCP = false; # Done by the network manager
      networkmanager.enable = false;

      #interfaces.*.useDHCP = false;
      
      hostName = hostName;
      wireless.enable = (if wireless then true else lib.mkForce false);

      hosts = lib.mkIf (!isVM) {
        "${network.miku}" = [ "miku.local" ];
        "${network.nishimiya}" = [ "nishimiya.local" ];
        "${network.ayame}" = [ "ayame.local" ];
        "${network.tamaki}" = [ "tamaki.local" ];
        "${network.mashu}" = [ "mashu.local" ];
      };

      firewall = {
        enable = true;
        extraCommands = lib.concatStringsSep "\n"
          (map (item: "iptables -A INPUT --source ${item} -j ACCEPT")
            (with network; [
              miku nishimiya tamaki ayame mashu
            ]));
      };
    };

    i18n.defaultLocale = "en_GB.UTF-8";
    console = {
      font = "Lat2-Terminus16";
      keyMap = "de";
    };

    users = {
      mutableUsers = false;

      extraUsers = {
        root = {
	        # Disable root login
	        hashedPassword = "*";
        };
      };
    };

    environment = {
      systemPackages = with pkgs; [
        htop
        vim
        git # Otherwise we cannot install home-manager
        git-crypt
        gnupg
        python3
        
        # RT scheduling
        rtkit
      ] ++ extraPackages pkgs
        ++ lib.optionals (!isVM) (with pkgs; [ gopass ]);

      sessionVariables = {
        # Prevent us from having to always type it out
        NIXOS_CONFIG = "/home/${config.system.singleUser}/Development/Personal/nixos-config/hosts/${config.networking.hostName}.nix";
      };
    };

    fonts.fonts = with pkgs; [
      # CJK fonts
      source-han-sans source-han-serif
    ];

    # We don't tolerate non-free software, except for Steam and Linux firmware
    nixpkgs.config.allowUnfreePredicate = pkg: builtins.elem (lib.getName pkg) [
      "firmwareLinuxNonfree" "microcodeAmd" "microcodeIntel"
      "steam" "steam-original" "steam-runtime"
      "discord"
    ];

    services = {
      connman = {
        enable = true;
        extraFlags = [ "--nodnsproxy" ];

        wifi = lib.mkIf wireless {
          # TODO: Maybe try out iwd
          backend = "wpa_supplicant";
        };
      };

      # TODO: Is this correct? Maybe run once
      timesyncd.enable = false;

      # Everyone needs sound
      pipewire = {
        enable = true;
        pulse.enable = true;
        alsa.enable = true;
        alsa.support32Bit = true;
      };

      # On desktop: Monitor keyboards, mice, ...
      # On portable devices: Monitor their battery
      upower.enable = true;

      # What generated entropy?
      haveged.enable = true;
      
      printing.enable = lib.mkDefault false;
      avahi.enable = false;

      # For debugging.
      # TODO: Lock to known IPs and keys
      sshd.enable = true;
    };

    # Don't wait for a network connection
    systemd.services.NetworkManager-wait-online.enable = false;
    
    security.sudo.extraConfig = ''
      Defaults env_keep += "NIXOS_CONFIG"
    '';

    hardware = {
      enableRedistributableFirmware = true;
      # This is a Pipewire household!
      pulseaudio.enable = false;

      opengl = {
      enable = true;
      driSupport32Bit = true;
      driSupport = true;
      extraPackages = with pkgs; [ vaapiVdpau libvdpau-va-gl ];
      };

      # Only a subset of my devices have bluetooth
      bluetooth = lib.mkIf wireless {
        enable = true;
      };
    } // (if wireless then {
      wifiInterface = wifiInterface;
    } else {});
    
    boot = {
      loader =  {
        systemd-boot.enable = true;
        efi.canTouchEfiVariables = true;
      };
    };

    fileSystems = fileSystems;
    swapDevices = swapDevices;
    
    system.stateVersion = "21.05";
  };
in lib.attrsets.recursiveUpdate baseConfig (extraOptions baseConfig)