nixos/syncthing: fix unix socket guiAddress handling

  settingsFormat = pkgs.formats.json { };

  cleanedConfig = converge (filterAttrsRecursive (_: v: v != null && v != { })) cfg.settings;

  isUnixGui = (builtins.substring 0 1 cfg.guiAddress) == "/";

  isUnixGui = lib.strings.hasPrefix "unix://" cfg.guiAddress;

  # Syncthing supports serving the GUI over Unix sockets. If that happens, the

  # API is served over the Unix socket as well.  This function returns the correct

    # note that the dot in front of `${path}` is the hostname, which is

    # required.

    then

      "--unix-socket ${cfg.guiAddress} http://.${path}"

      "--unix-socket ${lib.strings.removePrefix "unix://" cfg.guiAddress} http://.${path}"

    # no adjustments are needed if cfg.guiAddress is a network address

    else

      "${cfg.guiAddress}${path}";

              )"

              for id in ''${stale_${conf_type}_ids}; do

                >&2 echo "Deleting stale device: $id"

                curl -X DELETE "${s.baseAddress}/$id"

                curl -X DELETE ${s.baseAddress}/$id

              done

            ''

          ))

      guiAddress = mkOption {

        type = types.str;

        default = "127.0.0.1:8384";

        apply = x: if lib.strings.hasPrefix "/" x then "unix://${x}" else x;

        description = ''

          The address to serve the web interface at.

        '';

              args = lib.escapeShellArgs (

                (lib.cli.toCommandLineGNU { } {

                  "no-browser" = true;

                  "gui-address" = (if isUnixGui then "unix://" else "") + cfg.guiAddress;

                  "gui-address" = cfg.guiAddress;

                  "config" = cfg.configDir;

                  "data" = cfg.databaseDir;

                })

              );

            in

            "${lib.getExe cfg.package} ${args}";

          RuntimeDirectory = "syncthing";

          MemoryDenyWriteExecute = true;

          NoNewPrivileges = true;

          PrivateDevices = true;