/// ============================================================
/// 【课堂习题 · 顶部计时与暂停联动】
///
/// 1:1 迁移 Vue exerciseTiming.js（createTimingHandlers）：
/// - 顶部计时（可暂停 / 继续），与倒计时组件联动；
/// - 按 recordId 缓存 / 恢复计时进度（实际逻辑按题目 answerTimeSecond
///   汇总，SP 缓存代码在 Vue 端已注释，这里仍保留 persist 写缓存）；
/// - 暂停时统计剩余未答题数，驱动暂停弹窗。
/// ============================================================
library;

import 'package:shared_preferences/shared_preferences.dart';
import 'package:new_learn/features/conquerPackage/classExercises/controllers/exercise_session.dart';
import 'package:new_learn/features/conquerPackage/classExercises/controllers/exercise_submit.dart';
import 'package:new_learn/features/conquerPackage/classExercises/controllers/exercise_timing.dart';

class ExerciseTimingHandlers {
  ExerciseTimingHandlers({
    required this.session,
    required this.bridge,
    required this.submit,
    required this.isPausePopupVisible,
    this.onUiTick,
  }) {
    timing = ExerciseTiming(onTick: (tick) {
      final total = timingOffsetMs + tick.elapsedMs;
      timingText = formatElapsed(total);
      timingRunning = tick.running;
      // 页面层据此刷新顶部计时胶囊（对标 Vue ref 赋值触发渲染）
      onUiTick?.call();
    });
  }

  final ExerciseSession session;
  final ExerciseUiBridge bridge;
  final ExerciseSubmitHandlers submit;

  /// 每次秒表 tick 后回调页面刷新 UI（计时文案）
  final void Function()? onUiTick;

  /// 暂停弹窗当前是否展示（对标 showPausePopup.value 读取）
  final bool Function() isPausePopupVisible;

  late final ExerciseTiming timing;

  /// 顶部计时文案
  String timingText = '00:00';

  /// 计时是否运行中
  bool timingRunning = true;

  /// 累计偏移（恢复的已学时长）
  int timingOffsetMs = 0;

  /// 暂停时剩余未答题数
  int remainingCount = 0;

  /// 恢复计时缓存（Vue 端实际使用题目 answerTimeSecond 汇总）
  void restoreTimingCache() {
    try {
      var totalStudyTime = 0;
      for (final item in session.questions) {
        totalStudyTime += item.answerTimeSecond;
      }
      if (totalStudyTime != 0) {
        timingOffsetMs = totalStudyTime * 1000;
        timingText = formatElapsed(totalStudyTime * 1000);
      } else {
        timingOffsetMs = 0;
        timingText = '00:00';
      }
    } catch (_) {
      timingOffsetMs = 0;
      timingText = '00:00';
    }
  }

  /// 持久化计时进度（view 模式 / 无 recordId 不写）
  Future<void> persistTimingCache() async {
    final keyId = session.recordId;
    if (session.isView || keyId.isEmpty) return;
    final elapsedMs = timingOffsetMs + timing.getElapsedMs();
    try {
      final prefs = await SharedPreferences.getInstance();
      await prefs.setString(
        'classExercises_timing_$keyId',
        // 与 Vue 一致：历史上存的是 JSON 字符串
        '{"elapsedMs":$elapsedMs}',
      );
    } catch (_) {
      // 忽略落盘失败
    }
  }

  /// 切换计时（对标 toggleTiming）
  void toggleTiming() {
    if (isPausePopupVisible()) return;
    if (timing.isRunning()) {
      timing.pause();
      session.countDownKey?.currentState?.pause();
      bridge.setPausePopupVisible(true);

      final list = submit.batchProcessQuestions();
      remainingCount =
          list.where((res) => res['answered'] != true).length;
      bridge.notifyListeners();
      return;
    }
    timing.resume();
    session.countDownKey?.currentState?.start();
  }

  /// 关闭暂停弹窗并继续（对标 handlePausePopupClose）
  void handlePausePopupClose() {
    bridge.setPausePopupVisible(false);
    if (!timing.isRunning()) timing.resume();
    session.countDownKey?.currentState?.start();
  }

  void dispose() {
    timing.stop();
  }
}