# Edit this configuration file to define what should be installed on
# your system.  Help is available in the configuration.nix(5) man page
# and in the NixOS manual (accessible by running ‘nixos-help’).

{ config, pkgs, lib, ... }:
let
  ipv4 = {
    address = "95.216.74.104";
    gateway = "95.216.74.65";
    netmask = "255.255.255.192";
    prefixLength = 26; # https://www.pawprint.net/designresources/netmask-converter.php
  };
  ipv6 = {
    address = "2a01:4f9:2b:a98::";
    gateway = "fe80::1";
    prefixLength = 64;
  };
  networkInterface = "eth0";
  hostName = "cobalt";
  hostId = "712ae82a";
in
{
  imports =
    [ # Include the results of the hardware scan.
      ./hardware-configuration.nix
    ];

  boot.supportedFilesystems = [ "zfs" ];
  networking.hostId = hostId;

  boot.loader.grub.enable = true;
  # boot.loader.grub.version = 2;
  boot.loader.grub.efiSupport = false;
  # boot.loader.grub.device = "nodev";

  # This should be done automatically, but explicitly declare it just in case.
  boot.loader.grub.copyKernels = true;
  # Make sure that you've listed all of the boot partitions here.
  boot.loader.grub.mirroredBoots = [
    { path = "/boot"; devices = ["/dev/disk/by-id/ata-ST4000NM0245-1Z2107_ZC17GW7G"]; }
    { path = "/boot-fallback"; devices = ["/dev/disk/by-id/ata-ST4000NM0245-1Z2107_ZC17GWB2"]; }
  ];

  # Boot normally when one of the boot partitions are missing
  fileSystems."/boot".options = [ "nofail" ];
  fileSystems."/boot-fallback".options = [ "nofail" ];

  # Erase your darlings
  boot.initrd.postDeviceCommands = lib.mkAfter ''
    zfs rollback -r rpool/local/root@blank
  '';

  # NOTE: replace these to boot.initrd.availableKernelModules?
  boot.kernelModules = [ "e1000e" ];
  boot.initrd.kernelModules = [ "e1000e" ];

  boot.kernelParams = [
    # See <https:#www.kernel.org/doc/Documentation/filesystems/nfs/nfsroot.txt> for documentation.
    # ip=<client-ip>:<server-ip>:<gw-ip>:<netmask>:<hostname>:<device>:<autoconf>:<dns0-ip>:<dns1-ip>:<ntp0-ip>
    # The server ip refers to the NFS server -- not needed in this case.
    "ip=${ipv4.address}::${ipv4.gateway}:${ipv4.netmask}:${hostName}-initrd:${networkInterface}:off:8.8.8.8"
  ];

  boot.initrd.network.enable = true;
  boot.initrd.network.ssh = {
    enable = true;

    # Using the same port as the actual SSH will cause clients to throw errors
    # related to host key mismatch.
    port = 2222;

    # This takes 'path's, not 'string's.
    hostKeys = [
      /boot/initrd-ssh-key
      /boot-fallback/initrd-ssh-key
    ];

    # Public ssh key to log into the initrd ssh
    authorizedKeys = [ "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIDi7GGOGVj1Y5Sc1EW6zEdrp78dS6hvmS348pqu9dUsB openpgp:0x6BE7BD6F" ];
  };
  boot.initrd.network.postCommands = ''
    cat <<EOF > /root/.profile
    if pgrep -x "zfs" > /dev/null
    then
      zfs load-key -a
      killall zfs
    else
      echo "ZFS is not running -- this could be a sign of failure."
    fi
    EOF
  '';


  networking.hostName = hostName; # Define your hostname.

  networking.useDHCP = false;
  networking.interfaces.${networkInterface} = {
    ipv4 = { addresses = [{ address = ipv4.address; prefixLength = ipv4.prefixLength; }]; };
    ipv6 = { addresses = [{ address = ipv6.address; prefixLength = ipv6.prefixLength; }]; };
  };
  networking.defaultGateway = ipv4.gateway;
  networking.defaultGateway6 = { address = ipv6.gateway; interface = networkInterface; };
  networking.nameservers = [ "8.8.8.8" ];

  # Set your time zone.
  time.timeZone = "UTC";

  users.users.root.initialHashedPassword = "";
  users.users.root.openssh.authorizedKeys.keys = [ "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIDi7GGOGVj1Y5Sc1EW6zEdrp78dS6hvmS348pqu9dUsB openpgp:0x6BE7BD6F" ];
  services.openssh.enable = true;
  services.openssh.permitRootLogin = "prohibit-password";
  # mkdir -p /persist/etc/ssh
  services.openssh.hostKeys = [
    {
      path = "/persist/ssh/ssh_host_ed25519_key";
      type = "ed25519";
    }
    {
      path = "/persist/ssh/ssh_host_rsa_key";
      type = "rsa";
      bits = 4096;
    }
  ];

  # impermanence requirement
  fileSystems."/persist".neededForBoot = true;

  # This value determines the NixOS release from which the default
  # settings for stateful data, like file locations and database versions
  # on your system were taken. It‘s perfectly fine and recommended to leave
  # this value at the release version of the first install of this system.
  # Before changing this value read the documentation for this option
  # (e.g. man configuration.nix or on https://nixos.org/nixos/options.html).
  system.stateVersion = "23.05"; # Did you read the comment?
}