let
  common = import ./common.nix;
in
rec {
  getKiwix = serviceData:
    let
      kiwix =
        if serviceData ? kiwix then
          common.ensureAttrset "config/services.nix kiwix" serviceData.kiwix
        else
          throw "config/services.nix must define kiwix attrset.";

      rootDir =
        if kiwix ? root_dir then
          common.ensureNonEmptyString "config/services.nix kiwix.root_dir" kiwix.root_dir
        else
          throw "config/services.nix kiwix.root_dir must exist.";

      webPort =
        if kiwix ? port then
          common.ensureInt "config/services.nix kiwix.port" kiwix.port
        else
          throw "config/services.nix kiwix.port must exist.";

      zimUrls =
        if kiwix ? urls then
          common.ensureList "config/services.nix kiwix.urls" kiwix.urls
        else
          throw "config/services.nix kiwix.urls must exist.";
    in
      {
        root_dir = rootDir;
        port = webPort;
        urls = zimUrls;
      };
}