stylix/modules/grub.nix

{ pkgs, config, lib, ... }:

with config.lib.stylix;
with config.stylix.fonts;
with config.lib.stylix.colors.withHashtag;

let
  # Grub requires fonts to be converted to "PFF2 format"
  # This function takes a font { name, package } and produces a .pf2 file
  mkGrubFont = font:
    pkgs.runCommand "${font.package.name}.pf2" {
      FONTCONFIG_FILE =
        pkgs.makeFontsConf { fontDirectories = [ font.package ]; };
    } ''
      # Use fontconfig to select the correct .ttf or .otf file based on name
      font=$(
        ${pkgs.fontconfig}/bin/fc-match -v "${font.name}" \
        | grep "file:" | cut -d '"' -f 2
      )

      # Convert to .pf2
      ${pkgs.grub2}/bin/grub-mkfont $font --output $out --size 17
    '';

in {
  options.stylix.targets.grub = {
    enable = config.lib.stylix.mkEnableTarget "GRUB" true;

    useImage = lib.mkOption {
      description = "Whether to use your wallpaper image as the GRUB background.";
      type = lib.types.bool;
      default = false;
    };
  };

  config.boot.loader.grub = lib.mkIf config.stylix.targets.grub.enable {
    backgroundColor = base00;
    # Need to override the NixOS splash, this will match the background
    splashImage = pixel "base00";

    # This font will be used for the GRUB terminal
    font = toString (mkGrubFont monospace);

    # TODO: Include OS icons
    theme = pkgs.runCommand "stylix-grub" {
      themeTxt = ''
        desktop-image: "background.png"
        desktop-image-scale-method: "crop"
        desktop-color: "${base00}"

        title-text: ""

        terminal-left: "10%"
        terminal-top: "20%"
        terminal-width: "80%"
        terminal-height: "60%"

        + progress_bar {
          left = 25%
          top = 80%+20  # 20 pixels below boot menu
          width = 50%
          height = 30

          id = "__timeout__"
          show_text = true
          font = "${sansSerif.name}"
          text = "@TIMEOUT_NOTIFICATION_MIDDLE@"

          border_color = "${base00}"
          bg_color = "${base00}"
          fg_color = "${base0B}"
          text_color = "${base05}"
        }

        + boot_menu {
          left = 25%
          top = 20%
          width = 50%
          height = 60%
          menu_pixmap_style = "background_*.png"

          item_height = 40
          item_icon_space = 8
          item_spacing = 0
          item_padding = 0
          item_font = "${sansSerif.name}"
          item_color = "${base05}"

          selected_item_color = "${base01}"
          selected_item_pixmap_style = "selection_*.png"
        }
      '';
      passAsFile = [ "themeTxt" ];
    } ''
      mkdir $out
      cp $themeTxtPath $out/theme.txt

      ${if config.stylix.targets.grub.useImage
      # Make sure the background image is .png by asking to convert it
      then
        "${pkgs.imagemagick}/bin/convert ${config.stylix.image} png32:$out/background.png"
      else
        "cp ${pixel "base00"} $out/background.png"}

      cp ${pixel "base01"} $out/background_c.png
      cp ${pixel "base0B"} $out/selection_c.png

      cp ${mkGrubFont sansSerif} $out/sans_serif.pf2
    '';
  };
}