infra/nix/os/modules/opinionatedDisk.nix

{
  lib,
  config,
  pkgs,
  ...
}:
with lib;
let
  cfg = config.hardware.opinionatedDisk;
  ownLib = pkgs.callPackage ../lib/default.nix { };

  earlyDiskId = cfg: if cfg.earlyDiskIdOverride != "" then cfg.earlyDiskIdOverride else cfg.diskId;
in
{
  options.hardware.opinionatedDisk = {
    enable = mkEnableOption "Enable opinionated filesystem layout";
    diskId = mkOption { type = types.str; };
    encrypted = mkOption {
      default = true;
      type = types.bool;
    };

    earlyDiskIdOverride = mkOption {
      default = "";
      type = types.str;
    };
  };

  config = lib.mkIf cfg.enable {
    fileSystems."/boot" = {
      device = ownLib.disk.bootFsDevice cfg.diskId;
      fsType = "vfat";
    };

    fileSystems."/" = {
      device = ownLib.disk.rootFsDevice cfg.diskId;
      fsType = "btrfs";
      options = [ "subvol=nixos" ];
    };

    fileSystems."/home" = {
      device = ownLib.disk.rootFsDevice cfg.diskId;
      fsType = "btrfs";
      options = [ "subvol=home" ];
    };

    swapDevices = [ { device = ownLib.disk.swapFsDevice cfg.diskId; } ];

    boot.loader.grub = {
      device = ownLib.disk.bootGrubDevice (earlyDiskId cfg);
      enableCryptodisk = cfg.encrypted;
    };

    boot.initrd.luks.devices = lib.optionalAttrs cfg.encrypted (
      builtins.listToAttrs [
        {
          name =
            let
              splitstring = builtins.split "/" (ownLib.disk.bootLuksDevice cfg.diskId);
              lastelem = (builtins.length splitstring) - 1;
            in
            builtins.elemAt splitstring lastelem;
          value = {
            device = ownLib.disk.bootLuksDevice cfg.diskId;

            preLVM = true;
            allowDiscards = true;
          };
        }
      ]
    );
  };
}