ark/hosts/lungmen/default.nix

{
  config,
  lib,
  pkgs,
  inputs,
  ...
}: let
  btrfsPartPath = "/dev/disk/by-label/NIXOS";
  btrfsOptions = ["compress-force=zstd" "noatime"];
  btrfsDiff =
    pkgs.writeScriptBin
    "btrfs-diff"
    ''
      #!${pkgs.bash}/bin/bash
      set -euo pipefail

      sudo mkdir -p /mnt
      sudo mount -o subvol=/ ${btrfsPartPath} /mnt

      OLD_TRANSID=$(sudo btrfs subvolume find-new /mnt/root-blank 9999999)

      sudo btrfs subvolume find-new "/mnt/root" "$OLD_TRANSID" |
      sed '$d' |
      cut -f17- -d' ' |
      sort |
      uniq |
      while read path; do
        path="/$path"
        if [ -L "$path" ]; then
          : # The path is a symbolic link, so is probably handled by NixOS already
        elif [ -d "$path" ]; then
          : # The path is a directory, ignore
        else
          echo "$path"
        fi
      done

      sudo umount /mnt
    '';
in {
  imports = with inputs;
  with nixos-hardware.nixosModules; [
    nixos.nixosModules.notDetected
    nixos-persistence.nixosModule
    common-pc-ssd
    common-pc
    common-gpu-amd
    common-cpu-amd
    ../../modules/network/dns
    ../../users/root
    ../../users/patriot
  ];

  boot = {
    tmpOnTmpfs = true;
    loader = {
      efi.canTouchEfiVariables = true;
      systemd-boot.enable = true;
      systemd-boot.configurationLimit = 10;
    };
    kernelPackages = pkgs.linuxPackages_latest;
    supportedFilesystems = ["btrfs"];
    initrd = {
      availableKernelModules = ["xhci_pci" "ahci" "usb_storage" "usbhid" "sd_mod"];
      kernelModules = ["amdgpu"];
    };
    kernelModules = ["kvm-amd"];
    extraModulePackages = [];
    initrd.postDeviceCommands =
      pkgs.lib.mkBefore
      ''
        mkdir -p /mnt
        mount -o subvol=/ ${btrfsPartPath} /mnt
        btrfs subvolume list -o /mnt/root |
        cut -f9 -d' ' |
        while read subvolume; do
          echo "deleting /$subvolume subvolume..."
          btrfs subvolume delete "/mnt/$subvolume"
        done &&
        echo "deleting /root subvolume..." &&
        btrfs subvolume delete /mnt/root
        echo "restoring blank /root subvolume"
        btrfs subvolume snapshot /mnt/root-blank /mnt/root
        umount /mnt
      '';
    kernel.sysctl = {"fs.inotify.max_user_watches" = 524288;};
  };

  fileSystems."/" = {
    device = btrfsPartPath;
    fsType = "btrfs";
    options = ["subvol=root"] ++ btrfsOptions;
  };
  fileSystems."/home" = {
    device = btrfsPartPath;
    fsType = "btrfs";
    options = ["subvol=home"] ++ btrfsOptions;
  };
  #fileSystems."/media/archive" = {
  #  device = "/dev/disk/by-uuid/f9b5f7f3-51e8-4357-8518-986b16311c71";
  #  fsType = "btrfs";
  #  options = btrfsOptions;
  #};
  fileSystems."/nix" = {
    device = btrfsPartPath;
    fsType = "btrfs";
    options = ["subvol=nix"] ++ btrfsOptions;
  };
  fileSystems."/persist" = {
    device = btrfsPartPath;
    fsType = "btrfs";
    options = ["subvol=persist"] ++ btrfsOptions;
    neededForBoot = true;
  };
  fileSystems."/boot" = {
    device = "/dev/disk/by-uuid/5784-BBB1";
    fsType = "vfat";
  };

  swapDevices = [];
  zramSwap = {
    enable = true;
    algorithm = "zstd";
  };

  nix.maxJobs = lib.mkDefault 4;
  security = {
    pam.loginLimits = [
      {
        domain = "*";
        type = "soft";
        item = "nofile";
        value = "524288";
      }
      {
        domain = "*";
        type = "hard";
        item = "nofile";
        value = "524288";
      }
    ];
    allowSimultaneousMultithreading = false;
    # Deleting root subvolume makes sudo show lecture every boot
    sudo.extraConfig = ''
      Defaults lecture = never
    '';
    rtkit.enable = true;
  };

  sound.enable = false;
  services.pipewire = {
    enable = true;
    alsa.enable = true;
    alsa.support32Bit = true;
    pulse.enable = true;
  };
  hardware = {
    opengl = {
      driSupport = true;
      driSupport32Bit = true;
      enable = true;
      extraPackages = with pkgs; [amdvlk libvdpau-va-gl vaapiVdpau libva vulkan-loader pipewire];
      extraPackages32 = with pkgs.pkgsi686Linux;
        [libvdpau-va-gl vaapiVdpau libva vulkan-loader pipewire] ++ [pkgs.driversi686Linux.amdvlk];
    };
    pulseaudio = {
      enable = false;
      support32Bit = true;
    };
  };

  fonts = {
    enableDefaultFonts = true;
    fontconfig.enable = true;
    fonts = [pkgs.dejavu_fonts];
  };

  environment = {
    systemPackages = [btrfsDiff pkgs.ntfs3g];
    pathsToLink = ["/share/zsh"];
    persistence."/persist" = {
      directories = ["/etc/nixos"];
      files = ["/etc/machine-id"];
    };
    variables = {
      VK_ICD_FILENAMES =
        lib.mkForce
        "${pkgs.amdvlk}/share/vulkan/icd.d/amd_icd64.json:${pkgs.driversi686Linux.amdvlk}/share/vulkan/icd.d/amd_icd32.json";
    };
    sessionVariables = {
      VK_ICD_FILENAMES =
        lib.mkForce
        "${pkgs.amdvlk}/share/vulkan/icd.d/amd_icd64.json:${pkgs.driversi686Linux.amdvlk}/share/vulkan/icd.d/amd_icd32.json";
    };
  };

  networking.interfaces.enp6s0.useDHCP = true;
  services = {
    earlyoom.enable = true;
    ipfs = {
      enable = false;
      enableGC = true;
      autoMount = true;
    };
    flatpak.enable = false;
    xserver.videoDrivers = ["amdgpu"];
  };

  virtualisation = {
    podman.enable = true;
    libvirtd.enable = false;
  };

  system.stateVersion = "20.09";
}