import 'dart:convert';

import 'package:flutter_secure_storage/flutter_secure_storage.dart';
import "package:gql_error_link/gql_error_link.dart";
import "package:gql_exec/gql_exec.dart";
import "package:gql_http_link/gql_http_link.dart";
import "package:gql_link/gql_link.dart";
import "package:gql_transform_link/gql_transform_link.dart";
import 'package:hive/hive.dart';



class HttpAuthLink extends Link {
  Link _link = "" as Link; //Link _link ;
  String _token = "" ; //String _token;

  HttpAuthLink() {
    _link = Link.concat(
      ErrorLink(onException: handleException),
      TransformLink(requestTransformer: transformRequest),
    );
  }

  Future<void> updateToken() async {
    // _token = await Future.delayed(
    //   Duration(milliseconds: 10),
    //       () => "Valid token",
    // );
    final FlutterSecureStorage secureStorage = const FlutterSecureStorage();
    var encryptionKey = base64Url.decode((await secureStorage.read(key: 'key'))!);
    var encryptedBox = await Hive.openBox('auth', encryptionCipher: HiveAesCipher(encryptionKey));
    _token=encryptedBox.get('token');
  }

  Stream<Response> handleException(Request request,
      NextLink forward,
      LinkException exception,) async* {
    if (exception is HttpLinkServerException &&
        exception.response.statusCode == 401) {
      await updateToken();

      yield* forward(request);

      return;
    }

    throw exception;
  }

  Request transformRequest(Request request) =>
      request.updateContextEntry<HttpLinkHeaders>(
            (headers) =>
            HttpLinkHeaders(
              headers: <String, String>{
                ...headers?.headers ?? <String, String>{},
                "Authorization": _token,
              },
            ),
      );

  @override
  Stream<Response> request(Request request, [forward]) async* {
    // if (_token == null) {
    //   await updateToken();
    // }
    if (_token == "") {
      await updateToken();
    }

    yield* _link.request(request, forward);
  }
}