// auth_refresh_singleflight_test.dart — refresh token 是「单次使用 + 轮换」,
// 并发 401 必须合并为一次刷新,否则旧 JTI 被多次消费 → 误判失效把用户踢下线
// (跨平台「放久了/更新后要重新登录」的根因)。
import 'dart:convert';

import 'package:flutter_test/flutter_test.dart';
import 'package:http/http.dart' as http;
import 'package:http/testing.dart';
import 'package:pangolin_vpn/services/auth_api.dart';
import 'package:pangolin_vpn/services/token_store.dart';
import 'package:pangolin_vpn/state/auth_provider.dart';

class _MemStore implements TokenStore {
  _MemStore({this.access, this.refresh});
  String? access;
  String? refresh;
  bool cleared = false;
  @override
  Future<String?> loadAccessToken() async => access;
  @override
  Future<String?> loadRefreshToken() async => refresh;
  @override
  Future<void> saveTokens({required String access, required String refresh}) async {
    this.access = access;
    this.refresh = refresh;
  }
  @override
  Future<void> clear() async {
    cleared = true;
    access = null;
    refresh = null;
  }
  @override
  Future<void> markOnboarded() async {}
  @override
  Future<bool> isOnboarded() async => true;
  @override
  Future<void> saveLastEmail(String email) async {}
  @override
  Future<String?> loadLastEmail() async => null;
}

void main() {
  test('并发刷新 single-flight:多个并发 refresh 只消费一次 refresh token', () async {
    var hits = 0;
    final client = MockClient((req) async {
      if (req.url.path == '/v1/auth/refresh') {
        hits++;
        final body = jsonDecode(req.body) as Map<String, dynamic>;
        // 模拟服务端单次使用:旧 JTI 一旦被轮换,再用就 401。
        if (body['refresh_token'] != 'rt-1') {
          return http.Response('{"error":"invalid_token"}', 401,
              headers: {'content-type': 'application/json'});
        }
        return http.Response('{"access_token":"at-2","refresh_token":"rt-2"}', 200,
            headers: {'content-type': 'application/json'});
      }
      return http.Response('not found', 404);
    });

    final store = _MemStore(access: 'at-1', refresh: 'rt-1');
    final n = AuthNotifier(store, api: AuthApi(baseUrl: 'http://test.local', client: client));
    await Future<void>.delayed(Duration.zero); // 等构造里的 _loadFromStore

    final results = await Future.wait([
      n.refresh(), n.refresh(), n.refresh(), n.refresh(), n.refresh(),
    ]);

    expect(hits, 1, reason: '并发刷新应只打一次 /v1/auth/refresh,旧 token 只消费一次');
    expect(results.every((r) => r), isTrue, reason: '所有并发调用都应拿到同一次成功刷新');
    expect(store.refresh, 'rt-2', reason: '应轮换到新 refresh token');
    expect(store.cleared, isFalse, reason: '不应误触发 logout');
    expect(n.state.accessToken, 'at-2');
  });

  test('刷新后可再次刷新(in-flight 完成后释放)', () async {
    var current = 'rt-1';
    final client = MockClient((req) async {
      final body = jsonDecode(req.body) as Map<String, dynamic>;
      if (body['refresh_token'] != current) {
        return http.Response('{"error":"invalid_token"}', 401,
            headers: {'content-type': 'application/json'});
      }
      final next = current == 'rt-1' ? 'rt-2' : 'rt-3';
      current = next;
      return http.Response('{"access_token":"at-$next","refresh_token":"$next"}', 200,
          headers: {'content-type': 'application/json'});
    });
    final store = _MemStore(access: 'at-1', refresh: 'rt-1');
    final n = AuthNotifier(store, api: AuthApi(baseUrl: 'http://test.local', client: client));
    await Future<void>.delayed(Duration.zero);

    expect(await n.refresh(), isTrue);
    expect(store.refresh, 'rt-2');
    expect(await n.refresh(), isTrue); // in-flight 已释放,用新 token 再刷
    expect(store.refresh, 'rt-3');
  });
}