nichts/modules/system/boot/module.nix

{
  config,
  lib,
  pkgs,
  ...
}: let
  inherit (lib.modules) mkForce mkDefault;
  inherit (lib.options) mkOption mkEnableOption;
  inherit (lib.types) int;

  cfg = config.modules.system.boot;
in {
  options.modules.system.boot = {
    grub.enable = mkEnableOption "Grub, a bloated boot loader";
    systemd-boot.enable = mkEnableOption "Poetteringboot";
    timeout = mkOption {
      description = ''
        Set the boot loader's timeout. This is 0 by default, but preferably longer on remote servers to make switching to previous generations easier.
      '';
      type = int;
      # I love spamming space
      default = 0;
    };
  };
  config = {
    assertions = [
      {
        assertion = cfg.systemd-boot.enable || cfg.grub.enable;
        message = "No bootloader is enabled.";
      }
      {
        assertion = cfg.systemd-boot.enable -> !cfg.grub.enable && cfg.grub.enable -> !cfg.systemd-boot.enable;
        message = "Please enable only ONE of systemd-boot or grub.";
      }
    ];
    boot = {
      tmp.useTmpfs = true;
      consoleLogLevel = 0;

      kernelParams = [
        "quiet"
        "splash"
        "rd.systemd.show_status=false"
        "rd.udev.log_level=3"
        "udev.log_priority=3"
        "boot.shell_on_fail"
      ];

      initrd = {
        verbose = false;
        systemd.enable = true;
      };
      loader = {
        efi.canTouchEfiVariables = true;
        timeout = mkDefault cfg.timeout;
        systemd-boot = {
          enable = cfg.systemd-boot.enable;
          # INFO: Leaving this enabled is a security vulneratibility,
          # since we can just start /bin/sh from there and get root access.
          # Since I have FDE, this isn't _as_ critical, but it would still be
          # a bad idea to leave it enabled
          editor = mkForce false;
          consoleMode = "auto";
          configurationLimit = 5;
        };
        grub = {
          enable = cfg.grub.enable;
          efiSupport = true;
          device = "nodev";
          configurationLimit = 5;
        };
      };
      plymouth = {
        enable = true;
        themePackages = [
          (pkgs.adi1090x-plymouth-themes.override
            {
              selected_themes = [
                "hud_3"
              ];
            })
        ];
        theme = "hud_3";
      };
    };
    powerManagement = {
      powerDownCommands = ''
        ${pkgs.plymouth} --show-splash
      '';
      resumeCommands = ''
        ${pkgs.plymouth} --quit
      '';
    };
  };
}