Solian/lib/providers/auth.dart

import 'dart:convert';

import 'package:flutter/material.dart';
import 'package:flutter_secure_storage/flutter_secure_storage.dart';
import 'package:oauth2/oauth2.dart' as oauth2;
import 'package:solian/utils/service_url.dart';

class AuthProvider extends ChangeNotifier {
  AuthProvider();

  final deviceEndpoint =
      getRequestUri('passport', '/api/notifications/subscribe');
  final tokenEndpoint = getRequestUri('passport', '/api/auth/token');
  final userinfoEndpoint = getRequestUri('passport', '/api/users/me');
  final redirectUrl = Uri.parse('solian://auth');

  static const clientId = 'solian';
  static const clientSecret = '_F4%q2Eea3';

  static const storage = FlutterSecureStorage();
  static const storageKey = 'identity';
  static const profileKey = 'profiles';

  /// Before use this variable to make request
  /// **MAKE SURE YOU HAVE CALL THE isAuthorized() METHOD**
  oauth2.Client? client;

  DateTime? lastRefreshedAt;

  Future<bool> loadClient() async {
    if (await storage.containsKey(key: storageKey)) {
      try {
        final credentials =
            oauth2.Credentials.fromJson((await storage.read(key: storageKey))!);
        client = oauth2.Client(credentials,
            identifier: clientId, secret: clientSecret);
        await fetchProfiles();
        return true;
      } catch (e) {
        signoff();
        return false;
      }
    } else {
      return false;
    }
  }

  Future<oauth2.Client> createClient(
      BuildContext context, String username, String password) async {
    if (await loadClient()) {
      return client!;
    }

    return await oauth2.resourceOwnerPasswordGrant(
      tokenEndpoint,
      username,
      password,
      identifier: clientId,
      secret: clientSecret,
      scopes: ['openid'],
      basicAuth: false,
    );
  }

  Future<void> fetchProfiles() async {
    if (client != null) {
      var userinfo = await client!.get(userinfoEndpoint);
      storage.write(key: profileKey, value: utf8.decode(userinfo.bodyBytes));
    }
    notifyListeners();
  }

  Future<void> refreshToken() async {
    if (client != null) {
      final credentials = await client!.credentials.refresh(
          identifier: clientId, secret: clientSecret, basicAuth: false);
      client = oauth2.Client(credentials,
          identifier: clientId, secret: clientSecret);
      storage.write(key: storageKey, value: credentials.toJson());
    }
    notifyListeners();
  }

  Future<void> signin(
      BuildContext context, String username, String password) async {
    client = await createClient(context, username, password);
    storage.write(key: storageKey, value: client!.credentials.toJson());

    await fetchProfiles();
  }

  void signoff() {
    storage.delete(key: profileKey);
    storage.delete(key: storageKey);
  }

  Future<bool> isAuthorized() async {
    const storage = FlutterSecureStorage();
    if (await storage.containsKey(key: storageKey)) {
      if (client == null) {
        await loadClient();
      }
      if (lastRefreshedAt == null ||
          DateTime.now()
              .subtract(const Duration(minutes: 3))
              .isAfter(lastRefreshedAt!)) {
        await refreshToken();
        lastRefreshedAt = DateTime.now();
      }
      return true;
    } else {
      return false;
    }
  }

  Future<dynamic> getProfiles() async {
    const storage = FlutterSecureStorage();
    return jsonDecode(await storage.read(key: profileKey) ?? '{}');
  }
}