{ pkgs, lib, config, ... }:
let
  cfg = config.dynamicism.for.harmonia;
  settingsFormat = pkgs.formats.toml { };

  # FIXME: referring to config.dynamicism.finalSettings.* in here
  # makes lib.checkAssertWarn in the generic module cause infinite recursion.
  finalSettings = config.services.harmonia.settings;

  configFile = settingsFormat.generate "harmonia-override.toml" finalSettings;
in
{
  dynamicism.for.harmonia = {
    source-options = [ "services.harmonia.settings" ];

    unitDropins."harmonia.service" = pkgs.writeTextFile {
      name = "harmonia-override.conf";
      text = ''
        [Service]
        Environment=CONFIG_FILE=${configFile}
      '';

      passthru = { inherit configFile; };
    };
  };
}