{
  config,
  lib,
  pkgs,
  util,
  ...
}:
# mako as the notification daemon: toasts, a do-not-disturb mode, and history recall.
let
  dndStatus = pkgs.writeShellScript "waybar-dnd-status" ''
    if ${lib.getExe' pkgs.mako "makoctl"} mode 2>/dev/null | ${lib.getExe pkgs.gnugrep} -qx dnd; then
      printf '{"text":"${util.glyph "f1f6"}","tooltip":"Do not disturb: on","class":"dnd"}\n'
    else
      printf '{"text":"${util.glyph "f0f3"}","tooltip":"Notifications on","class":"active"}\n'
    fi
  '';

  dndToggle = pkgs.writeShellScript "waybar-dnd-toggle" ''
    ${lib.getExe' pkgs.mako "makoctl"} mode -t dnd >/dev/null 2>&1
    ${lib.getExe' pkgs.procps "pkill"} -RTMIN+8 waybar
  '';
in
{
  options.modules.desktop.session.mako.enable = lib.mkEnableOption "the mako notification daemon";

  config = lib.mkIf config.modules.desktop.session.mako.enable {
    home-manager.users.${config.user.name} = {
      # Colors and the popup font come from Stylix's mako target, so only
      # behaviour is set here.
      services.mako = {
        enable = true;

        settings = {
          # Toasts auto-dismiss into history rather than lingering.
          # mako's own default of 0 leaves every notification on screen until acted on.
          default-timeout = 5000;

          # The do-not-disturb mode.
          # Invisible hides the toasts but still records them to history.
          # Missed notifications can therefore be recalled.
          "mode=dnd".invisible = true;
        };
      };
    };

    registry.keybind.${config.networking.hostName}.mako-history = {
      keys = "SUPER + N";
      action = {
        kind = "exec";
        command = "${lib.getExe' pkgs.mako "makoctl"} restore";
      };
    };

    registry.waybar.${config.networking.hostName}."custom/dnd" = {
      order = 80;
      settings = {
        return-type = "json";
        exec = "${dndStatus}";
        on-click = "${dndToggle}";
        interval = "once";
        signal = 8;
      };
    };
  };
}