storage:

{ config, ... }:

let
  rootUuid = "44444444-4444-4444-8888-888888888888";
  rootPart = "/dev/disk/by-uuid/${rootUuid}";
in

{
  imports = [
    ../hardware/bpi-r3/${storage}.nix
    ../hosts/router
  ];
  networking.hostName = "nixos-router";

  systemd.enableEmergencyMode = false;
  boot.kernel.sysctl = {
    "net.core.default_qdisc" = "fq";
    "net.ipv4.tcp_congestion_control" = "bbr";
  };

  fileSystems = {
    # mount root on tmpfs
    "/" =     { device = "none"; fsType = "tmpfs"; neededForBoot = true;
                options = [ "defaults" "size=2G" "mode=755" ]; };
    "/persist" =
              { device = rootPart; fsType = "btrfs"; neededForBoot = true;
                options = [ "compress=zstd:15" "subvol=@" ]; };
    "/boot" =
              { device = rootPart; fsType = "btrfs"; neededForBoot = true;
                options = [ "subvol=@boot" ]; };
    "/nix" =
              { device = rootPart; fsType = "btrfs"; neededForBoot = true;
                options = [ "compress=zstd:15" "subvol=@nix" ]; };
  };

  impermanence = {
    enable = true;
    path = /persist;
    directories = [
      { directory = /home/${config.common.mainUsername}; user = config.common.mainUsername; group = "users"; mode = "0700"; }
      { directory = /root; mode = "0700"; }
    ];
  };

  # technically hostapd/lan0..4 interface config should be here as well
  # but for easier demonstration i'll keep it all in ../hosts/router
}