/// ============================================================
/// 【课堂习题 · 数据加载】（1:1 迁移 Vue exerciseLoad.js）
///
/// - loadStartOvercome：edit 模式，GetRecordData + GetListByRecordQuestion，
///   解析题目、追加 sort、补 hasOptionChildrenQuestion、挂学科 id；
/// - loadSubmitReport：view 模式，GetSubmitReport，错题模式过滤重排。
///
/// 调试：loadStartOvercome 在接口返回后会（仅 kDebugMode）追加
/// assets/mock/class_exercises_edit.json（取自 Vue exerciseLoad.js）。
/// ============================================================
library;

import 'dart:convert';

import 'package:flutter/foundation.dart';
import 'package:flutter/services.dart';
import 'package:new_learn/core/api/conquerPackage/classExercises/api.dart';
import 'package:new_learn/core/utils/question/exam_answer_card.dart';
import 'package:new_learn/core/utils/question/question_constant.dart';
import 'package:new_learn/core/utils/question/question_parser.dart';
import 'package:new_learn/features/conquerPackage/classExercises/controllers/exercise_session.dart';
import 'package:new_learn/features/conquerPackage/classExercises/controllers/exercise_sort.dart';
import 'package:new_learn/features/conquerPackage/classExercises/models/question_model.dart';

class ExerciseLoadResult {
  const ExerciseLoadResult({
    required this.recordId,
    required this.navBarTitle,
    required this.baseSubjectId,
    required this.questions,
    required this.originalMaxSort,
  });

  final String recordId;
  final String navBarTitle;
  final int? baseSubjectId;
  final List<QuestionModel> questions;

  /// view 全量题号最大值（错题模式下供页面保留原始题号总数）
  final int originalMaxSort;
}

class ExerciseLoad {
  ExerciseLoad._();

  /// edit 模式加载（对标 loadStartOvercome）
  ///
  /// [inputRecordId] 路由带入的 recordId；[currentIndex] 为起始大题索引，
  /// 该题会写入当前 startTime；[baseSubjectIdOverride] 为路由/base 传入的
  /// 学科 id（对应 Vue 的 baseSubjectId ?? resRecord.baseSubjectId）。
  static Future<ExerciseLoadResult> loadStartOvercome({
    required String inputRecordId,
    int currentIndex = 0,
    int? baseSubjectIdOverride,
  }) async {
    final api = ClassExercisesApi.instance;
    final resRecord = await api.getRecordData(inputRecordId);
    final resList = await api.getListByRecordQuestion(inputRecordId);

    // 接口照常请求；debug 测试时再把 exerciseLoad.js 里的 JSON 试题追加进去
    await _injectDebugQuestions(resList.items);

    final navBarTitle = '${resRecord.name}专项智能攻克';
    final subjectId = baseSubjectIdOverride ?? resRecord.baseSubjectId;
    final subjectType = getSubjectTypeById(subjectId) ?? 0;

    final parsed = <Map<String, dynamic>>[];
    for (var i = 0; i < resList.items.length; i++) {
      final item = resList.items[i];
      if (i == currentIndex) {
        item['startTime'] = getCurrentISO();
      }
      // 1=图片作答 / 手写；0=输入框
      item['iSFilllankItemUpload'] = subjectType;
      parsed.add(parseQuestionData(item, mergeOriginalChilds: true));
    }

    var list = appendQuestionSort(parsed);
    list = appendExamQuestionChildOptionStatus(list, subjectId);

    final bsid = subjectId;
    for (final q in list) {
      q['baseSubjectId'] = bsid;
    }

    return ExerciseLoadResult(
      recordId: resRecord.recordId,
      navBarTitle: navBarTitle,
      baseSubjectId: bsid,
      questions: list.map(QuestionModel.new).toList(),
      originalMaxSort: 0,
    );
  }

  /// view 模式加载（对标 loadSubmitReport）
  ///
  /// [isWrong] 为 true 时只保留答错题并重排 wrongSort，同时把起始索引置 0
  /// （调用方不要再用旧 currentIndex）。
  static Future<ExerciseLoadResult> loadSubmitReport({
    required String packId,
    bool isWrong = false,
    int currentIndex = 0,
  }) async {
    final api = ClassExercisesApi.instance;
    final res = await api.getSubmitReport(packId);

    final navBarTitle = '${res.name}专项智能攻克';
    final subjectType = getSubjectTypeById(res.baseSubjectId) ?? 0;

    final parsed = <Map<String, dynamic>>[];
    for (var i = 0; i < res.questions.length; i++) {
      final item = res.questions[i];
      if (i == currentIndex) {
        item['startTime'] = getCurrentISO();
      }
      item['iSFilllankItemUpload'] = subjectType;
      parsed.add(parseQuestionData(item, mergeOriginalChilds: true));
    }

    var fullList = appendQuestionSort(parsed);
    fullList = appendExamQuestionChildOptionStatus(fullList, res.baseSubjectId);

    var maxSort = 0;
    for (final item in fullList.map(QuestionModel.new).toList()) {
      final end = getQuestionSortRange(item).end;
      if (end > maxSort) maxSort = end;
    }

    List<QuestionModel> questions;
    if (isWrong) {
      questions = filterWrongQuestions(fullList.map(QuestionModel.new).toList());
    } else {
      questions = fullList.map(QuestionModel.new).toList();
    }

    for (final q in questions) {
      q.baseSubjectId = res.baseSubjectId;
    }

    return ExerciseLoadResult(
      recordId: res.id,
      navBarTitle: navBarTitle,
      baseSubjectId: res.baseSubjectId,
      questions: questions,
      originalMaxSort: maxSort,
    );
  }

  /// 【仅 debug 测试】真实接口请求完成后，把 Vue exerciseLoad.js 里的
  /// JSON 试题追加到列表尾部（对标 JS 里 `res.push(...listX)`）。
  /// release 包直接 no-op；测完删掉 [loadStartOvercome] 里的调用即可。
  static Future<void> _injectDebugQuestions(
    List<Map<String, dynamic>> items,
  ) async {
    if (!kDebugMode) return;
    try {
      final raw = await rootBundle
          .loadString('assets/mock/class_exercises_edit.json');
      final list = jsonDecode(raw);
      if (list is List) {
        for (final item in list) {
          if (item is Map) {
            items.add(Map<String, dynamic>.from(item));
          }
        }
        debugPrint('[ExerciseLoad] 已追加 ${list.length} 道测试 JSON 试题');
      }
    } catch (e) {
      debugPrint('[ExerciseLoad] 测试 JSON 追加失败: $e');
    }
  }
}