import 'package:flutter/widgets.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:patbond_flutter/analytics/session_tracker.dart';

void main() {
  final uuidV7 = RegExp(
    r'^[0-9a-f]{8}-[0-9a-f]{4}-7[0-9a-f]{3}-[0-9a-f]{4}-[0-9a-f]{12}$',
  );

  group('SessionTracker', () {
    test('冷启动生成 UUIDv7 格式的 sessionId', () {
      final tracker = SessionTracker();
      expect(tracker.sessionId, matches(uuidV7));
    });

    test('短后台（≤30 分钟）resume 后沿用原 sessionId', () {
      var clock = DateTime.utc(2026, 9, 7, 10);
      final tracker = SessionTracker(now: () => clock);
      final original = tracker.sessionId;

      tracker.didChangeAppLifecycleState(AppLifecycleState.paused);
      clock = clock.add(const Duration(minutes: 30));
      tracker.didChangeAppLifecycleState(AppLifecycleState.resumed);

      expect(tracker.sessionId, original);
    });

    test('长后台（>30 分钟）resume 后生成新 sessionId', () {
      var clock = DateTime.utc(2026, 9, 7, 10);
      final tracker = SessionTracker(now: () => clock);
      final original = tracker.sessionId;

      tracker.didChangeAppLifecycleState(AppLifecycleState.paused);
      clock = clock.add(const Duration(minutes: 31));
      tracker.didChangeAppLifecycleState(AppLifecycleState.resumed);

      expect(tracker.sessionId, isNot(original));
      expect(tracker.sessionId, matches(uuidV7));
    });

    test('真实生命周期级联下退后台时刻不被 inactive 覆盖', () {
      // 前台恢复时状态机级联 paused → hidden → inactive → resumed，
      // 若 inactive 覆盖记时，31 分钟长后台会被误判为 0 分钟。
      var clock = DateTime.utc(2026, 9, 7, 10);
      final tracker = SessionTracker(now: () => clock);
      final original = tracker.sessionId;

      tracker.didChangeAppLifecycleState(AppLifecycleState.inactive);
      tracker.didChangeAppLifecycleState(AppLifecycleState.hidden);
      tracker.didChangeAppLifecycleState(AppLifecycleState.paused);
      clock = clock.add(const Duration(minutes: 31));
      tracker.didChangeAppLifecycleState(AppLifecycleState.hidden);
      tracker.didChangeAppLifecycleState(AppLifecycleState.inactive);
      tracker.didChangeAppLifecycleState(AppLifecycleState.resumed);

      expect(tracker.sessionId, isNot(original));
    });

    test('连续多次短后台幂等，仅超阈值才换新', () {
      var clock = DateTime.utc(2026, 9, 7, 10);
      final tracker = SessionTracker(now: () => clock);
      final original = tracker.sessionId;

      for (var i = 0; i < 3; i++) {
        tracker.didChangeAppLifecycleState(AppLifecycleState.paused);
        clock = clock.add(const Duration(minutes: 10));
        tracker.didChangeAppLifecycleState(AppLifecycleState.resumed);
        expect(tracker.sessionId, original);
      }

      tracker.didChangeAppLifecycleState(AppLifecycleState.paused);
      clock = clock.add(const Duration(minutes: 35));
      tracker.didChangeAppLifecycleState(AppLifecycleState.resumed);
      expect(tracker.sessionId, isNot(original));
    });
  });
}