import 'dart:convert';

import 'package:flutter_test/flutter_test.dart';
import 'package:patbond_flutter/analytics/analytics_event_store.dart';
import 'package:shared_preferences/shared_preferences.dart';

Map<String, dynamic> event(int seq) => {
  'eventId': 'id-$seq',
  'eventName': 'auth_login_succeeded',
  'seq': seq,
};

void main() {
  group('AnalyticsEventStore', () {
    test('事件持久化后新实例冷启动可恢复（顺序保持旧 → 新）', () async {
      SharedPreferences.setMockInitialValues({});
      final store = AnalyticsEventStore();
      await store.restore();
      for (var i = 0; i < 45; i++) {
        await store.add(event(i));
      }

      final reborn = AnalyticsEventStore();
      await reborn.restore();

      expect(reborn.length, 45);
      expect(reborn.events.first['seq'], 0);
      expect(reborn.events.last['seq'], 44);
      // 45 条按容量 20 分段应为 3 段
      final prefs = await SharedPreferences.getInstance();
      final index =
          jsonDecode(prefs.getString(AnalyticsEventStore.segIndexKey)!) as List;
      expect(index.length, 3);
    });

    test('超过 500 条总上限时丢最旧整段', () async {
      SharedPreferences.setMockInitialValues({});
      final store = AnalyticsEventStore();
      await store.restore();
      for (var i = 0; i < 520; i++) {
        await store.add(event(i));
      }

      // 第 501 条触发淘汰最旧一段（20 条），此后回落到上限内
      expect(store.length, 500);
      expect(store.events.first['seq'], 20);
      expect(store.events.last['seq'], 519);
      expect(store.droppedCount, 20);
    });

    test('损坏段丢弃不崩溃，其余段正常恢复且索引被清理', () async {
      SharedPreferences.setMockInitialValues({
        AnalyticsEventStore.segIndexKey: jsonEncode(['bad', 'good']),
        '${AnalyticsEventStore.segKeyPrefix}bad': '{not-valid-json[[',
        '${AnalyticsEventStore.segKeyPrefix}good': jsonEncode([event(7)]),
      });

      final store = AnalyticsEventStore();
      await store.restore();

      expect(store.length, 1);
      expect(store.events.single['seq'], 7);
      expect(store.droppedCount, 1);
      final prefs = await SharedPreferences.getInstance();
      expect(prefs.getString('${AnalyticsEventStore.segKeyPrefix}bad'), isNull);
      expect(jsonDecode(prefs.getString(AnalyticsEventStore.segIndexKey)!), [
        'good',
      ]);
    });

    test('段索引本身损坏时清扫孤儿段、从空队列重建', () async {
      SharedPreferences.setMockInitialValues({
        AnalyticsEventStore.segIndexKey: 'garbage-not-json',
        '${AnalyticsEventStore.segKeyPrefix}orphan': jsonEncode([event(1)]),
      });

      final store = AnalyticsEventStore();
      await store.restore();

      expect(store.length, 0);
      final prefs = await SharedPreferences.getInstance();
      expect(
        prefs.getString('${AnalyticsEventStore.segKeyPrefix}orphan'),
        isNull,
      );
      // 可继续正常写入
      await store.add(event(2));
      expect(store.length, 1);
    });

    test('takeBatch 封段：在途批次不受新事件影响，删段后新事件保留', () async {
      SharedPreferences.setMockInitialValues({});
      final store = AnalyticsEventStore();
      await store.restore();
      for (var i = 0; i < 5; i++) {
        await store.add(event(i));
      }

      final batch = store.takeBatch(50);
      // 模拟上传在途期间进入的新事件
      await store.add(event(99));

      expect(batch.events.length, 5);
      await store.removeSegments(batch.segmentIds);
      expect(store.length, 1);
      expect(store.events.single['seq'], 99);
    });

    test('takeBatch 按段拼批不超过单批上限', () async {
      SharedPreferences.setMockInitialValues({});
      final store = AnalyticsEventStore();
      await store.restore();
      for (var i = 0; i < 60; i++) {
        await store.add(event(i));
      }

      // 段容量 20、单批上限 50 → 每批最多 2 整段（40 条）
      final first = store.takeBatch(50);
      expect(first.events.length, 40);
      await store.removeSegments(first.segmentIds);
      final second = store.takeBatch(50);
      expect(second.events.length, 20);
    });

    test('上传成功删段后 shared_preferences 无残留', () async {
      SharedPreferences.setMockInitialValues({});
      final store = AnalyticsEventStore();
      await store.restore();
      for (var i = 0; i < 20; i++) {
        await store.add(event(i));
      }

      final batch = store.takeBatch(50);
      await store.removeSegments(batch.segmentIds);

      expect(store.length, 0);
      final prefs = await SharedPreferences.getInstance();
      expect(
        prefs.getKeys().where(
          (key) => key.startsWith(AnalyticsEventStore.segKeyPrefix),
        ),
        isEmpty,
      );
      expect(
        jsonDecode(prefs.getString(AnalyticsEventStore.segIndexKey)!),
        isEmpty,
      );
    });

    test('未调用 restore（持久化不可用）时降级为纯内存队列', () async {
      final store = AnalyticsEventStore();
      await store.add(event(1));
      expect(store.length, 1);
      final batch = store.takeBatch(50);
      await store.removeSegments(batch.segmentIds);
      expect(store.length, 0);
    });
  });
}