spotube/lib/provider/authentication/authentication.dart

import 'dart:async';
import 'dart:convert';
import 'dart:io';

import 'package:collection/collection.dart';
import 'package:desktop_webview_window/desktop_webview_window.dart';
import 'package:dio/dio.dart';
import 'package:dio_http2_adapter/dio_http2_adapter.dart';
import 'package:drift/drift.dart';
import 'package:flutter_inappwebview/flutter_inappwebview.dart'
    hide X509Certificate;
import 'package:hooks_riverpod/hooks_riverpod.dart';
import 'package:otp_util/otp_util.dart';
// ignore: implementation_imports
import 'package:otp_util/src/utils/generic_util.dart';
import 'package:spotube/collections/routes.dart';
import 'package:spotube/components/dialogs/prompt_dialog.dart';
import 'package:spotube/extensions/context.dart';
import 'package:spotube/models/database/database.dart';
import 'package:spotube/provider/database/database.dart';
import 'package:spotube/services/logger/logger.dart';
import 'package:spotube/utils/platform.dart';
import 'package:spotube/utils/service_utils.dart';

extension ExpirationAuthenticationTableData on AuthenticationTableData {
  bool get isExpired => DateTime.now().isAfter(expiration);

  String? getCookie(String key) => cookie.value
      .split("; ")
      .firstWhereOrNull((c) => c.trim().startsWith("$key="))
      ?.trim()
      .split("=")
      .last
      .replaceAll(";", "");
}

class AuthenticationNotifier extends AsyncNotifier<AuthenticationTableData?> {
  static final Dio dio = () {
    final dio = Dio()
      ..httpClientAdapter = Http2Adapter(
        ConnectionManager(
          idleTimeout: const Duration(seconds: 10),
          onClientCreate: (uri, clientSettings) {
            clientSettings.onBadCertificate = (X509Certificate cert) {
              return uri.host.endsWith("spotify.com");
            };
          },
        ),
      );

    return dio;
  }();

  @override
  build() async {
    final database = ref.watch(databaseProvider);

    final data = await (database.select(database.authenticationTable)
          ..where((s) => s.id.equals(0)))
        .getSingleOrNull();

    Timer? refreshTimer;

    ref.listenSelf((prevData, newData) async {
      if (newData.asData?.value == null) return;

      if (newData.asData!.value!.isExpired) {
        await refreshCredentials();
      }

      // set the refresh timer
      refreshTimer?.cancel();
      refreshTimer = Timer(
        newData.asData!.value!.expiration.difference(DateTime.now()),
        () => refreshCredentials(),
      );
    });

    final subscription =
        database.select(database.authenticationTable).watch().listen(
      (event) {
        state = AsyncData(event.isEmpty ? null : event.first);
      },
    );

    ref.onDispose(() {
      subscription.cancel();
      refreshTimer?.cancel();
    });

    return data;
  }

  Future<void> refreshCredentials() async {
    final database = ref.read(databaseProvider);
    final refreshedCredentials =
        await credentialsFromCookie(state.asData!.value!.cookie.value);

    await database
        .update(database.authenticationTable)
        .replace(refreshedCredentials);
  }

  Future<void> login(String cookie) async {
    final database = ref.read(databaseProvider);
    final refreshedCredentials = await credentialsFromCookie(cookie);

    await database
        .into(database.authenticationTable)
        .insert(refreshedCredentials, mode: InsertMode.replace);
  }

  String base32FromBytes(Uint8List e, String secretSauce) {
    var t = 0;
    var n = 0;
    var r = "";
    for (int i = 0; i < e.length; i++) {
      n = n << 8 | e[i];
      t += 8;
      while (t >= 5) {
        r += secretSauce[n >>> t - 5 & 31];
        t -= 5;
      }
    }
    if (t > 0) {
      r += secretSauce[n << 5 - t & 31];
    }
    return r;
  }

  Uint8List cleanBuffer(String e) {
    e = e.replaceAll(" ", "");
    final t = List.filled(e.length ~/ 2, 0);
    final n = Uint8List.fromList(t);
    for (int r = 0; r < e.length; r += 2) {
      n[r ~/ 2] = int.parse(e.substring(r, r + 2), radix: 16);
    }
    return n;
  }

  Future<String> generateTotp() async {
    const secretSauce = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
    final secretCipherBytes = const [
      12,
      56,
      76,
      33,
      88,
      44,
      88,
      33,
      78,
      78,
      11,
      66,
      22,
      22,
      55,
      69,
      54
    ].mapIndexed((t, e) => e ^ t % 33 + 9).toList();

    final secretBytes = cleanBuffer(
      utf8
          .encode(secretCipherBytes.join(""))
          .map((e) => e.toRadixString(16))
          .join(),
    );

    final secret = base32FromBytes(secretBytes, secretSauce);

    final res = await dio.get(
      "https://open.spotify.com/server-time",
      options: Options(
        headers: {
          "Host": "open.spotify.com",
          "User-Agent": ServiceUtils.randomUserAgent(
            kIsDesktop ? UserAgentDevice.desktop : UserAgentDevice.mobile,
          ),
          "accept": "*/*",
        },
      ),
    );
    final serverTimeSeconds = res.data["serverTime"] as int;

    final totp = TOTP(
      secret: secret,
      algorithm: OTPAlgorithm.SHA1,
      digits: 6,
      interval: 30,
    );

    return totp.generateOTP(
      input: Util.timeFormat(
        time: DateTime.fromMillisecondsSinceEpoch(serverTimeSeconds * 1000),
        interval: 30,
      ),
    );
  }

  Future<Response> getToken({
    required String totp,
    required int timestamp,
    String mode = "transport",
    String? spDc,
  }) async {
    assert(mode == "transport" || mode == "init");

    final accessTokenUrl = Uri.parse(
      "https://open.spotify.com/get_access_token?reason=$mode&productType=web-player"
      "&totp=$totp&totpVer=5&ts=$timestamp",
    );

    final res = await dio.getUri(
      accessTokenUrl,
      options: Options(
        headers: {
          "Cookie": spDc ?? "",
          "User-Agent": ServiceUtils.randomUserAgent(
            kIsDesktop ? UserAgentDevice.desktop : UserAgentDevice.mobile,
          ),
        },
      ),
    );

    return res;
  }

  Future<AuthenticationTableCompanion> credentialsFromCookie(
    String cookie,
  ) async {
    try {
      final spDc = cookie
          .split("; ")
          .firstWhereOrNull((c) => c.trim().startsWith("sp_dc="))
          ?.trim();

      final totp = await generateTotp();

      final timestamp = (DateTime.now().millisecondsSinceEpoch / 1000).floor();

      var res = await getToken(
        totp: totp,
        timestamp: timestamp,
        spDc: spDc,
        mode: "transport",
      );

      if ((res.data["accessToken"]?.length ?? 0) != 374) {
        res = await getToken(
          totp: totp,
          timestamp: timestamp,
          spDc: spDc,
          mode: "init",
        );
      }

      final body = res.data as Map<String, dynamic>;

      if (body["accessToken"] == null) {
        AppLogger.reportError(
          "The access token is only ${body["accessToken"]?.length} characters long instead of 374\n"
          "Your authentication probably doesn't work",
          StackTrace.current,
        );
      }

      return AuthenticationTableCompanion.insert(
        id: const Value(0),
        cookie: DecryptedText("${res.headers["set-cookie"]?.join(";")}; $spDc"),
        accessToken: DecryptedText(body['accessToken']),
        expiration: DateTime.fromMillisecondsSinceEpoch(
          body['accessTokenExpirationTimestampMs'],
        ),
      );
    } catch (e) {
      if (rootNavigatorKey.currentContext != null) {
        showPromptDialog(
          context: rootNavigatorKey.currentContext!,
          title: rootNavigatorKey.currentContext!.l10n
              .error("Authentication Failure"),
          message: e.toString(),
          cancelText: null,
        );
      }
      rethrow;
    }
  }

  Future<void> logout() async {
    state = const AsyncData(null);
    final database = ref.read(databaseProvider);
    await (database.delete(database.authenticationTable)
          ..where((s) => s.id.equals(0)))
        .go();
    if (kIsMobile) {
      WebStorageManager.instance().deleteAllData();
      CookieManager.instance().deleteAllCookies();
    }
    if (kIsDesktop) {
      await WebviewWindow.clearAll();
    }
  }
}

final authenticationProvider =
    AsyncNotifierProvider<AuthenticationNotifier, AuthenticationTableData?>(
  () => AuthenticationNotifier(),
);