// ==UserScript==
// @name         华谊题库助手 · CSV导出与划词检索
// @namespace    local.huayi.question-bank
// @version      1.2.9
// @description  全网页快捷键唤出、本地题库文字检索与自动选择答案，按库导入导出；每页默认完全隐藏。
// @match        http://*/*
// @match        https://*/*
// @match        file:///*
// @run-at       document-start
// @grant        unsafeWindow
// @grant        GM_getValue
// @grant        GM_setValue
// @grant        GM_deleteValue
// @grant        GM_registerMenuCommand
// @grant        GM_addValueChangeListener
// @grant        GM_removeValueChangeListener
// ==/UserScript==

(function () {
'use strict';

// ---- src/core.js ----
/* Pure question-bank operations. No page access or network requests. */
const QBCore = (() => {
  'use strict';

  const TYPES = new Set(['single', 'multiple', 'judge', 'unknown']);
  const STATUSES = new Set(['confirmed', 'missing', 'conflict']);
  const ANSWER_EVIDENCE = new Set(['submitted-list', 'answer-response', 'bound-dom', 'explicit-standard']);
  const TYPE_NAMES = { single: '单选题', multiple: '多选题', judge: '判断题', unknown: '未知' };
  const STATUS_NAMES = { confirmed: '已确认', missing: '待补', conflict: '冲突' };
  const own = (value, key) => Object.prototype.hasOwnProperty.call(value, key);
  const text = (value) => value == null ? '' : String(value);
  const unique = (values) => [...new Set(values)];
  const clean = (value) => text(value).replace(/\u00a0/g, ' ').trim();
  // Do not use NFKC: it changes superscripts, units and some mathematical symbols.
  const normalized = (value) => clean(value).replace(/\s+/gu, '');
  const normalizedStem = (value) => normalized(clean(value).replace(/^(?:第\s*\d+\s*题[\s、.．:：]*|\d+\s*[、．]\s*|\d+\.\s+)/u, ''));
  const sorted = (values) => [...values].sort();
  const sameArray = (a, b) => JSON.stringify(sorted(a)) === JSON.stringify(sorted(b));

  function idText(value, name) {
    if (typeof value === 'number' && !Number.isSafeInteger(value)) throw new Error(`${name} 是不安全的数字，请以字符串提供`);
    if (value != null && !['string', 'number'].includes(typeof value)) throw new Error(`${name} 必须是字符串`);
    return clean(value);
  }

  function stringArray(value, name) {
    if (value == null) return [];
    if (!Array.isArray(value) || value.some((item) => typeof item !== 'string' && typeof item !== 'number')) {
      throw new Error(`${name} 必须是字符串数组`);
    }
    return unique(value.map((item) => idText(item, name)).filter(Boolean));
  }

  function judgeText(value) {
    const result = clean(value);
    if (/^(正确|对|是|√|true)$/i.test(result)) return '正确';
    if (/^(错误|错|否|×|false)$/i.test(result)) return '错误';
    return result;
  }

  const answerText = (value, type) => type === 'judge' ? judgeText(value) : clean(value);
  const comparableAnswer = (value, type) => normalized(answerText(value, type));
  const optionContents = (record) => record.options.map((option) => comparableAnswer(option.text, record.type));
  const sameContent = (a, b) => normalizedStem(a.stem) === normalizedStem(b.stem) &&
    (a.type === b.type || a.type === 'unknown' || b.type === 'unknown') && sameArray(optionContents(a), optionContents(b));

  function sourceInfo(value) {
    const source = value && typeof value === 'object' && !Array.isArray(value) ? value : {};
    const result = { kind: clean(source.kind) || 'unknown', url: clean(source.url), observedAt: clean(source.observedAt) || new Date().toISOString() };
    if (clean(source.batchId)) result.batchId = idText(source.batchId, '采集批次ID');
    return result;
  }

  function recordKey(record) {
    const bank = record.bankId || record.bankName;
    if (record.questionId) return `id:${JSON.stringify([bank, record.questionId])}`;
    // Keep the complete signature, rather than a short hash whose collisions could merge answers.
    const fingerprint = [bank, record.type, normalizedStem(record.stem), sorted(optionContents(record))];
    if (record.contentOccurrence != null) fingerprint.push(record.contentOccurrence);
    return `fp:${JSON.stringify(fingerprint)}`;
  }

  function normalizeRecord(input) {
    if (!input || typeof input !== 'object' || Array.isArray(input)) throw new Error('题目记录必须是对象');
    if (typeof input.stem !== 'string' || !input.stem.trim()) throw new Error('题干不能为空');
    const type = input.type == null ? 'unknown' : input.type;
    if (!TYPES.has(type)) throw new Error(`不支持的题型：${text(type)}`);
    if (input.answerStatus != null && !STATUSES.has(input.answerStatus)) throw new Error(`无效答案状态：${text(input.answerStatus)}`);
    if (input.answerEvidence != null && !ANSWER_EVIDENCE.has(input.answerEvidence)) throw new Error(`无效答案证据：${text(input.answerEvidence)}`);
    if (input.options != null && !Array.isArray(input.options)) throw new Error('选项必须是数组');
    const options = (input.options || []).map((option, index) => {
      if (typeof option === 'string') option = { text: option };
      if (!option || typeof option !== 'object' || typeof option.text !== 'string' || !option.text.trim()) throw new Error('选项内容不能为空');
      return { id: idText(option.id, '选项ID'), text: clean(option.text), label: clean(option.label) || (index < 26 ? String.fromCharCode(65 + index) : String(index + 1)) };
    });
    const correctOptionIds = stringArray(input.correctOptionIds, '正确选项ID');
    let answerTexts = stringArray(input.answerTexts, '正确答案内容').map((value) => answerText(value, type));
    answerTexts = unique(answerTexts);
    let answerStatus = input.answerStatus || (correctOptionIds.length || answerTexts.length ? 'confirmed' : 'missing');
    const conflicts = Array.isArray(input.conflicts) ? input.conflicts.filter((item) => item && typeof item === 'object').map((item) => JSON.parse(JSON.stringify(item))) : [];
    let inconsistency = '';
    const derivedTexts = [];
    if (correctOptionIds.length && options.length) {
      for (const id of correctOptionIds) {
        const matches = options.filter((option) => option.id === id);
        if (matches.length !== 1) inconsistency = '正确选项ID无法唯一对应已保存选项';
        else derivedTexts.push(answerText(matches[0].text, type));
      }
      if (!inconsistency && answerTexts.length && !sameArray(unique(answerTexts.map((value) => comparableAnswer(value, type))), unique(derivedTexts.map((value) => comparableAnswer(value, type))))) {
        inconsistency = '正确选项ID与正确答案内容不一致';
      }
      if (!answerTexts.length && !inconsistency) answerTexts = unique(derivedTexts);
    }
    if (['single', 'judge'].includes(type) && (answerTexts.length > 1 || correctOptionIds.length > 1)) inconsistency = '单选或判断题存在多个正确答案';
    if (options.length && ['single', 'multiple', 'judge'].includes(type) && answerTexts.some((answer) => !options.some((option) => comparableAnswer(option.text, type) === comparableAnswer(answer, type)))) {
      inconsistency = '正确答案内容不属于已保存选项';
    }
    if (answerStatus === 'confirmed' && !answerTexts.length && !correctOptionIds.length) answerStatus = 'missing';
    if (answerStatus !== 'missing' && inconsistency) {
      answerStatus = 'conflict';
      if (!conflicts.some((item) => item.reason === inconsistency)) conflicts.push({ reason: inconsistency, answerTexts: [...answerTexts], correctOptionIds: [...correctOptionIds] });
    }
    // Explicitly missing data must never carry an apparently confirmed answer forward.
    if (answerStatus === 'missing') answerTexts = [];
    const source = sourceInfo(input.source);
    const record = {
      bankId: idText(input.bankId, '题库ID'), bankName: clean(input.bankName) || '未命名题库',
      questionId: idText(input.questionId, '题目ID'), type, stem: clean(input.stem), options,
      correctOptionIds: answerStatus === 'missing' ? [] : correctOptionIds, answerTexts, answerStatus,
      explanation: clean(input.explanation), source, updatedAt: clean(input.updatedAt) || source.observedAt, conflicts,
    };
    for (const field of ['questionIndex', 'contentOccurrence']) {
      if (input[field] != null) {
        if (!Number.isSafeInteger(input[field]) || input[field] < 0) throw new Error(`${field} 必须为非负整数`);
        record[field] = input[field];
      }
    }
    if (own(input, 'questionIdAliases')) record.questionIdAliases = unique([...stringArray(input.questionIdAliases, '题目ID别名'), record.questionId].filter(Boolean));
    if (input.answerEvidence != null) record.answerEvidence = input.answerEvidence;
    if (input.answerSource || answerStatus === 'confirmed') record.answerSource = sourceInfo(input.answerSource || source);
    record.key = recordKey(record);
    return record;
  }

  function answerSignature(record) {
    // IDs retain how many identical-text options are correct; answerTexts is a set.
    if (record.correctOptionIds.length && record.options.length) {
      const correct = record.options.filter((option) => record.correctOptionIds.includes(option.id));
      return JSON.stringify(sorted(correct.map((option) => comparableAnswer(option.text, record.type))));
    }
    if (record.answerTexts.length) return JSON.stringify(sorted(record.answerTexts.map((value) => comparableAnswer(value, record.type))));
    return JSON.stringify(sorted(record.correctOptionIds.map((value) => `id:${value}`)));
  }

  const answerProvenance = record => record?.answerSource || record?.source;
  const legacyJudgeListSource = source => source?.kind === 'network' && /\/upm\/(?:wrong\/)?start(?:[?#]|$)/u.test(source.url || '');
  const judgeAnswerResponseSource = source => source?.kind === 'network' && /\/upm\/[^/]+\/users\/[^/]+\/(?:wrong\/)?answer(?:[?#]|$)/u.test(source.url || '');
  const trustedAnswerProvenance = record => ANSWER_EVIDENCE.has(record?.answerEvidence) || judgeAnswerResponseSource(answerProvenance(record)) ||
    /^(?:csv-import|json-import|manual|manual-import|import)$/u.test(answerProvenance(record)?.kind || '');

  // Old practice-list judgeAnswer values contained unsubmitted placeholders.
  // This explicit migration preserves the raw input for a durable backup and
  // touches only judge records with that evidenced legacy provenance or an
  // unverified old DOM answer that could have inherited the same placeholder.
  function repairLegacyJudgeAnswers(input) {
    if (!Array.isArray(input)) throw new Error('题库必须是数组');
    const changed = [];
    const unverifiedLegacySource = record => (legacyJudgeListSource(answerProvenance(record)) || answerProvenance(record)?.kind === 'dom') && !trustedAnswerProvenance(record);
    let records = input;
    for (let index = 0; index < input.length; index++) {
      const original = input[index];
      if (original?.type !== 'judge') continue;
      const snapshots = Array.isArray(original.conflicts) ? original.conflicts : [];
      const contaminated = unverifiedLegacySource(original) && original.answerStatus !== 'missing' || snapshots.some(unverifiedLegacySource);
      if (!contaminated) continue;
      const record = normalizeRecord(original);
      const candidates = [], unresolved = [];
      const addCandidate = (candidate, snapshot) => {
        if (unverifiedLegacySource(candidate)) return;
        // An old DOM observation may merely have inherited the list value.
        // Its presence in a contaminated record is not independent evidence.
        if (!trustedAnswerProvenance(candidate)) {
          const kind = answerProvenance(candidate)?.kind || 'unknown';
          if (!['dom', 'unknown'].includes(kind)) unresolved.push(snapshot || conflictSnapshot(record, '未确认的判断题答案来源'));
          return;
        }
        if (!candidate.answerTexts?.length && !candidate.correctOptionIds?.length) {
          if (snapshot) unresolved.push(snapshot);
          return;
        }
        try {
          const source = answerProvenance(candidate);
          const restored = normalizeRecord({ ...record, ...candidate, bankId: record.bankId, bankName: record.bankName,
            questionId: record.questionId, source: record.source, answerSource: source,
            answerEvidence: candidate.answerEvidence || (judgeAnswerResponseSource(source) ? 'answer-response' : undefined),
            answerStatus: 'confirmed', conflicts: [] });
          if (restored.answerStatus !== 'confirmed') {
            if (snapshot) unresolved.push(snapshot);
            else unresolved.push(conflictSnapshot(restored, '标准答案证据与选项不一致'));
          } else candidates.push(restored);
        } catch (_) { if (snapshot) unresolved.push(snapshot); }
      };
      for (const snapshot of snapshots) {
        if (!snapshot || typeof snapshot !== 'object') continue;
        addCandidate({ ...snapshot, answerEvidence: snapshot.answerEvidence }, snapshot);
      }
      if (record.answerStatus !== 'missing') addCandidate(record);
      let repaired;
      for (const candidate of candidates) repaired = repaired ? mergeNormalizedRecords(repaired, candidate) : candidate;
      if (!repaired) repaired = normalizeRecord({ ...record, answerStatus: unresolved.length ? 'conflict' : 'missing',
        answerTexts: [], correctOptionIds: [], answerSource: undefined, answerEvidence: undefined, conflicts: [] });
      if (unresolved.length) repaired = normalizeRecord({ ...repaired, answerStatus: 'conflict',
        conflicts: distinctConflicts([...repaired.conflicts, ...unresolved]) });
      // Restore collection/identity metadata even when an older answer snapshot
      // supplied the trustworthy stem, options and answer IDs atomically.
      repaired = normalizeRecord({ ...record, ...repaired, source: record.source, updatedAt: record.updatedAt,
        answerSource: repaired.answerSource, answerEvidence: repaired.answerEvidence,
        questionIdAliases: record.questionIdAliases, questionIndex: record.questionIndex, contentOccurrence: record.contentOccurrence });
      if (!own(record, 'questionIdAliases')) delete repaired.questionIdAliases;
      if (JSON.stringify(repaired) === JSON.stringify(record)) continue;
      if (records === input) records = input.slice();
      records[index] = repaired;
      changed.push({ index, key: record.key, reason: repaired.answerStatus === 'confirmed' ? 'recovered-proven-judge-answer' :
        repaired.answerStatus === 'conflict' ? 'retained-proven-judge-conflict' : 'unverified-legacy-judge-answer', original });
    }
    return { records, changed };
  }

  // Old versions compared the list of ID-derived answers with a text set. When
  // two correct options shared text, that comparison produced a false conflict.
  // Repair only that evidenced shape; normalizeRecord keeps all other explicit
  // conflicts conservative. The original inputs are returned for durable backup.
  function repairDuplicateOptionConflicts(input) {
    if (!Array.isArray(input)) throw new Error('题库必须是数组');
    const repaired = [];
    const legacyReason = '正确选项ID与正确答案内容不一致';
    const mergeReason = '同一题目出现不同或不一致的标准答案';
    const ids = values => Array.isArray(values) && values.length > 0 && values.every(value => typeof value === 'string' && clean(value)) &&
      new Set(values.map(clean)).size === values.length ? values.map(clean) : null;
    const answers = values => Array.isArray(values) && values.length > 0 && values.every(value => typeof value === 'string' && normalized(value))
      ? unique(values.map(normalized)) : null;
    const optionSignature = options => {
      if (!Array.isArray(options) || !options.length || options.some(option => !option || typeof option !== 'object' ||
        typeof option.id !== 'string' || !clean(option.id) || typeof option.text !== 'string' || !normalized(option.text))) return null;
      if (new Set(options.map(option => clean(option.id))).size !== options.length) return null;
      return options.map(option => JSON.stringify([clean(option.id), normalized(option.text)]));
    };
    const records = input.map((original, index) => {
      const record = normalizeRecord(original);
      if (record.type !== 'multiple' || record.answerStatus !== 'conflict' || !Array.isArray(original.conflicts) || !original.conflicts.length) return record;
      const optionIds = optionSignature(original.options);
      const correctIds = ids(original.correctOptionIds);
      const answerSet = answers(original.answerTexts);
      if (!optionIds || !correctIds || !answerSet) return record;
      const derived = correctIds.map(id => record.options.find(option => option.id === id));
      if (derived.some(option => !option)) return record;
      const derivedAnswers = derived.map(option => normalized(option.text));
      if (new Set(derivedAnswers).size === derivedAnswers.length || !sameArray(unique(derivedAnswers), answerSet)) return record;
      const source = original.answerSource || original.source;
      const sameSource = candidate => candidate && typeof candidate === 'object' && !Array.isArray(candidate) && source &&
        typeof source === 'object' && !Array.isArray(source) && (clean(source.batchId) || (clean(source.url) && clean(source.observedAt))) &&
        ['kind', 'url', 'observedAt', 'batchId'].every(field => clean(candidate[field]) === clean(source[field]));
      const valid = original.conflicts.every(snapshot => {
        if (!snapshot || typeof snapshot !== 'object' || Array.isArray(snapshot) || ![legacyReason, mergeReason].includes(snapshot.reason)) return false;
        const snapshotIds = ids(snapshot.correctOptionIds), snapshotAnswers = answers(snapshot.answerTexts);
        if (!snapshotIds || !snapshotAnswers || !sameArray(snapshotIds, correctIds) || !sameArray(snapshotAnswers, answerSet)) return false;
        if ((own(snapshot, 'stem') || own(snapshot, 'options')) && (!own(snapshot, 'stem') || !own(snapshot, 'options'))) return false;
        if (own(snapshot, 'stem') && (typeof snapshot.stem !== 'string' || normalized(snapshot.stem) !== normalized(record.stem))) return false;
        if (own(snapshot, 'options')) {
          const signature = optionSignature(snapshot.options);
          if (!signature || !sameArray(signature, optionIds)) return false;
        }
        for (const field of ['type', 'bankId', 'bankName', 'questionId']) if (own(snapshot, field) && snapshot[field] !== record[field]) return false;
        if (own(snapshot, 'answerStatus') && !['confirmed', 'conflict'].includes(snapshot.answerStatus)) return false;
        for (const field of ['source', 'answerSource']) if (own(snapshot, field) && !sameSource(snapshot[field])) return false;
        for (const field of ['batchId', 'batch']) if (own(snapshot, field) &&
          (typeof snapshot[field] !== 'string' || !clean(snapshot[field]) || clean(snapshot[field]) !== clean(source?.batchId))) return false;
        return true;
      });
      if (!valid || !original.conflicts.some(snapshot => snapshot.reason === legacyReason)) return record;
      const restored = normalizeRecord({ ...record, answerStatus: 'confirmed', conflicts: [] });
      if (restored.answerStatus !== 'confirmed') return record;
      repaired.push({ index, key: record.key, bankId: record.bankId, questionId: record.questionId, reason: 'duplicate-correct-option-text', original });
      return restored;
    });
    return { records, repaired };
  }

  // Upgrade the old text-only representation only against an evidenced complete
  // current network snapshot. A matching text fragment alone cannot prove that
  // two image questions are equivalent.
  function upgradeLegacyImageRecords(existingInput, incomingInput, { bankId = '', expectedCount, fullSnapshot = false } = {}) {
    if (!Array.isArray(existingInput) || !Array.isArray(incomingInput)) throw new Error('题库必须是数组');
    const existing = existingInput.map(normalizeRecord), incoming = incomingInput.map(normalizeRecord);
    const unchanged = () => ({ existing, incoming, upgraded: [] });
    if (!fullSnapshot || !bankId || !Number.isSafeInteger(expectedCount) || expectedCount < 1 || incoming.length !== expectedCount) return unchanged();
    const isList = source => source?.kind === 'network' && /\/(?:upm\/(?:wrong\/)?start|pra\/[^/]+\/questions)\/?$/u.test(source.url || '') && Number.isFinite(Date.parse(source.observedAt));
    const batch = incoming[0]?.source.batchId;
    if (!batch || incoming.some(record => record.bankId !== bankId || !isList(record.source) || record.source.batchId !== batch ||
      !Number.isSafeInteger(record.questionIndex) || record.questionIndex < 0 || record.questionIndex >= expectedCount) ||
      new Set(incoming.map(record => record.questionIndex)).size !== expectedCount || new Set(incoming.map(record => record.questionId)).size !== expectedCount || incoming.some(record => !record.questionId)) return unchanged();
    const marker = /\[图片:https?:\/\/[^\]\s]+\]/gu;
    const strip = value => normalized(value.replace(marker, ''));
    const imageCount = record => [record.stem, ...record.options.map(option => option.text)].reduce((count, value) => count + (value.match(marker)?.length || 0), 0);
    const signature = record => JSON.stringify([record.type, strip(record.stem), sorted(record.options.map(option => strip(option.text)))]);
    const existingBank = existing.filter(record => record.bankId === bankId);
    const countSignatures = records => {
      const map = new Map();
      for (const record of records) { const key = signature(record); map.set(key, (map.get(key) || 0) + 1); }
      return map;
    };
    const oldCounts = countSignatures(existingBank), newCounts = countSignatures(incoming);
    const previousBySignature = new Map(), indexCounts = new Map(), originalByKey = new Map();
    existing.forEach((record, index) => { if (!originalByKey.has(record.key)) originalByKey.set(record.key, existingInput[index]); });
    for (const record of existingBank) {
      const key = signature(record);
      if (!previousBySignature.has(key)) previousBySignature.set(key, record);
      indexCounts.set(record.questionIndex, (indexCounts.get(record.questionIndex) || 0) + 1);
    }
    const correctContents = record => {
      if (record.answerStatus !== 'confirmed' || record.conflicts.length || !record.correctOptionIds.length || !record.options.length ||
        record.options.some(option => !option.id) || new Set(record.options.map(option => option.id)).size !== record.options.length) return null;
      const options = record.correctOptionIds.map(id => record.options.find(option => option.id === id));
      return options.some(option => !option) ? null : options.map(option => strip(option.text));
    };
    const upgraded = [], removed = new Set();
    for (let index = 0; index < incoming.length; index++) {
      const current = incoming[index], key = signature(current);
      if (!imageCount(current) || current.type === 'unknown' || current.options.length < 2 || !strip(current.stem) ||
        oldCounts.get(key) !== 1 || newCounts.get(key) !== 1 || new Set(current.options.map(option => strip(option.text))).size !== current.options.length ||
        current.options.some(option => !strip(option.text))) continue;
      const previous = previousBySignature.get(key);
      if (!previous.questionId || imageCount(previous) || previous.type !== current.type ||
        !Number.isSafeInteger(previous.questionIndex) || previous.questionIndex !== current.questionIndex || !isList(previous.source) ||
        (previous.source.batchId ? previous.source.batchId === batch : previous.source.observedAt === current.source.observedAt) ||
        indexCounts.get(current.questionIndex) !== 1) continue;
      const oldAnswers = correctContents(previous), newAnswers = correctContents(current);
      if (!oldAnswers || !newAnswers || !sameArray(oldAnswers, newAnswers) ||
        !sameArray(unique(previous.answerTexts.map(strip)), unique(current.answerTexts.map(strip)))) continue;
      const replacement = normalizeRecord({ ...current, questionIdAliases: unique([...(current.questionIdAliases || []), previous.questionId, ...(previous.questionIdAliases || [])]) });
      incoming[index] = replacement;
      removed.add(previous.key);
      upgraded.push({ original: originalByKey.get(previous.key), replacement,
        bankId, expectedCount, batchId: batch, questionIndex: current.questionIndex });
    }
    return { existing: existing.filter(record => !removed.has(record.key)), incoming, upgraded };
  }

  // These are deliberately evidenced legacy spellings, not an HTML decoder.
  // Literal entities elsewhere stay distinct in normalization/search/compaction.
  function upgradeLegacyMathEntities(existingInput, incomingInput, { bankId = '', expectedCount, fullSnapshot = false } = {}) {
    if (!Array.isArray(existingInput) || !Array.isArray(incomingInput)) throw new Error('题库必须是数组');
    const existing = existingInput.map(normalizeRecord), incoming = incomingInput.map(normalizeRecord);
    const unchanged = () => ({ existing, incoming, upgraded: [] });
    if (!fullSnapshot || !bankId || !Number.isSafeInteger(expectedCount) || expectedCount < 1 || incoming.length !== expectedCount) return unchanged();
    const isList = source => source?.kind === 'network' && /\/(?:upm\/(?:wrong\/)?start|pra\/[^/]+\/questions)\/?$/u.test(source.url || '') && Number.isFinite(Date.parse(source.observedAt));
    const batch = incoming[0]?.source.batchId;
    if (!batch || incoming.some(record => record.bankId !== bankId || !isList(record.source) || record.source.batchId !== batch ||
      !Number.isSafeInteger(record.questionIndex) || record.questionIndex < 0 || record.questionIndex >= expectedCount || !record.questionId) ||
      new Set(incoming.map(record => record.questionIndex)).size !== expectedCount || new Set(incoming.map(record => record.questionId)).size !== expectedCount) return unchanged();
    const content = record => [record.stem, ...record.options.map(option => option.text)];
    const entities = { '&times;': '×', '&plusmn;': '±' };
    const hasEntity = record => content(record).some(value => /&(?:times|plusmn);/.test(value));
    const canonical = value => normalized(value.replace(/&(?:times|plusmn);/g, entity => entities[entity]));
    const signature = record => JSON.stringify([record.type, canonical(record.stem), sorted(record.options.map(option => canonical(option.text)))]);
    const optionPairs = record => record.options.map(option => JSON.stringify([option.id, canonical(option.text)]));
    const correctContents = record => {
      if (record.answerStatus !== 'confirmed' || record.conflicts.length || !record.correctOptionIds.length || record.options.length < 2 ||
        record.options.some(option => !option.id) || new Set(record.options.map(option => option.id)).size !== record.options.length ||
        new Set(record.options.map(option => canonical(option.text))).size !== record.options.length) return null;
      const selected = record.correctOptionIds.map(id => record.options.find(option => option.id === id));
      return selected.some(option => !option) ? null : selected.map(option => canonical(option.text));
    };
    const sameAnswers = (a, b) => {
      const left = correctContents(a), right = correctContents(b);
      return left && right && sameArray(left, right) && sameArray(a.correctOptionIds, b.correctOptionIds) &&
        sameArray(unique(a.answerTexts.map(canonical)), unique(b.answerTexts.map(canonical)));
    };
    const sameModern = (record, current) => !hasEntity(record) && record.type === current.type && record.questionIndex === current.questionIndex &&
      normalized(record.stem) === normalized(current.stem) && sameArray(optionPairs(record), optionPairs(current)) && isList(record.source) && sameAnswers(record, current);
    const bank = existing.filter(record => record.bankId === bankId), upgraded = [], removed = new Set();
    const incomingCounts = new Map(), bankBySignature = new Map(), legacyBySignature = new Map(), bankByIndex = new Map(), originalByKey = new Map();
    existing.forEach((record, index) => { if (!originalByKey.has(record.key)) originalByKey.set(record.key, existingInput[index]); });
    const add = (map, key, record) => {
      if (!map.has(key)) map.set(key, []);
      map.get(key).push(record);
    };
    for (const record of incoming) {
      const key = signature(record);
      incomingCounts.set(key, (incomingCounts.get(key) || 0) + 1);
    }
    for (const record of bank) {
      const key = signature(record);
      add(bankBySignature, key, record);
      add(bankByIndex, record.questionIndex, record);
      if (hasEntity(record)) add(legacyBySignature, key, record);
    }
    for (let index = 0; index < incoming.length; index++) {
      const current = incoming[index], key = signature(current);
      if (hasEntity(current) || current.type === 'unknown' || !correctContents(current) || incomingCounts.get(key) !== 1) continue;
      const candidates = legacyBySignature.get(key) || [];
      if (candidates.length !== 1) continue;
      const previous = candidates[0];
      if (!previous.questionId || previous.questionIndex !== current.questionIndex || !Number.isSafeInteger(previous.questionIndex) ||
        !isList(previous.source) || (previous.source.batchId ? previous.source.batchId === batch : previous.source.observedAt === current.source.observedAt) ||
        !sameArray(optionPairs(previous), optionPairs(current)) || !sameAnswers(previous, current)) continue;
      // A previous failed export may already contain both spellings. Permit only
      // fully agreeing modern copies at that very same source position; distinct
      // literal-entity questions and duplicate occurrences remain untouched.
      if ([...(bankBySignature.get(key) || []), ...(bankByIndex.get(current.questionIndex) || [])].some(record =>
        record.key !== previous.key && !sameModern(record, current))) continue;
      const replacement = normalizeRecord({ ...current, questionIdAliases: unique([...(current.questionIdAliases || []), previous.questionId, ...(previous.questionIdAliases || [])]) });
      incoming[index] = replacement;
      removed.add(previous.key);
      upgraded.push({ original: originalByKey.get(previous.key), replacement,
        kind: 'math-entity', bankId, expectedCount, batchId: batch, questionIndex: current.questionIndex });
    }
    return { existing: existing.filter(record => !removed.has(record.key)), incoming, upgraded };
  }

  function conflictSnapshot(record, reason) {
    const snapshot = { reason, stem: record.stem, options: record.options.map((option) => ({ ...option })), answerTexts: [...record.answerTexts], correctOptionIds: [...record.correctOptionIds], source: record.answerSource || record.source };
    if (record.answerEvidence) snapshot.answerEvidence = record.answerEvidence;
    return snapshot;
  }

  function distinctConflicts(conflicts) {
    const byContent = new Map();
    for (const item of conflicts) {
      const key = JSON.stringify([item.reason, item.stem, item.options, item.answerTexts, item.correctOptionIds,
        item.answerEvidence || '', item.source?.kind || '', item.source?.url || '']);
      if (!byContent.has(key)) byContent.set(key, item);
    }
    return [...byContent.values()].slice(-40);
  }

  function mergeRecord(existing, incoming) {
    return mergeNormalizedRecords(normalizeRecord(existing), normalizeRecord(incoming));
  }

  // Internal callers already validated both records. Keep validation at the
  // public boundary and on the merged result without cloning both inputs again.
  function mergeNormalizedRecords(oldRecord, newRecord) {
    if (oldRecord.key !== newRecord.key) throw new Error('不能合并不同题目的记录');
    const contentMatches = sameContent(oldRecord, newRecord);
    const explanation = newRecord.explanation || oldRecord.explanation;
    const metadata = {};
    for (const field of ['questionIndex', 'contentOccurrence']) {
      if (newRecord[field] != null || oldRecord[field] != null) metadata[field] = newRecord[field] ?? oldRecord[field];
    }
    if (own(oldRecord, 'questionIdAliases') || own(newRecord, 'questionIdAliases')) metadata.questionIdAliases = unique([
      ...(oldRecord.questionIdAliases || []), ...(newRecord.questionIdAliases || []), oldRecord.questionId, newRecord.questionId
    ].filter(Boolean));
    const base = { ...newRecord, ...metadata, explanation };
    const conflicts = [...oldRecord.conflicts, ...newRecord.conflicts];
    const conflictAlready = oldRecord.answerStatus === 'conflict' || newRecord.answerStatus === 'conflict';
    const sameOptionIdentities = oldRecord.options.length > 0 && oldRecord.options.every((option) => option.id) &&
      unique(oldRecord.options.map((option) => option.id)).length === oldRecord.options.length &&
      sameArray(oldRecord.options.map((option) => JSON.stringify([option.id, comparableAnswer(option.text, oldRecord.type)])),
        newRecord.options.map((option) => JSON.stringify([option.id, comparableAnswer(option.text, newRecord.type)])));
    const exactIdsDiffer = sameOptionIdentities && oldRecord.correctOptionIds.length && newRecord.correctOptionIds.length &&
      !sameArray(oldRecord.correctOptionIds, newRecord.correctOptionIds);
    const answersDiffer = oldRecord.answerStatus === 'confirmed' && newRecord.answerStatus === 'confirmed' &&
      (answerSignature(oldRecord) !== answerSignature(newRecord) || exactIdsDiffer);
    const contentChanged = !contentMatches && oldRecord.answerStatus !== 'missing';
    if (conflictAlready || answersDiffer || contentChanged) {
      const reason = contentChanged ? '同一题目ID的题干或选项发生变化' : '同一题目出现不同或不一致的标准答案';
      if (oldRecord.answerStatus !== 'missing') conflicts.push(conflictSnapshot(oldRecord, reason));
      if (newRecord.answerStatus !== 'missing') conflicts.push(conflictSnapshot(newRecord, reason));
      const answerRecord = newRecord.answerStatus !== 'missing' ? newRecord : oldRecord;
      return normalizeRecord({ ...base, answerTexts: answerRecord.answerTexts, correctOptionIds: answerRecord.correctOptionIds,
        answerSource: answerRecord.answerSource || answerRecord.source, answerEvidence: answerRecord.answerEvidence, answerStatus: 'conflict',
        conflicts: distinctConflicts(conflicts) });
    }
    if (newRecord.answerStatus === 'missing' && oldRecord.answerStatus === 'confirmed') {
      // The incoming DOM may use different IDs/order. Keep the original answer's own options and IDs together.
      return normalizeRecord({ ...oldRecord, ...metadata, bankName: newRecord.bankName || oldRecord.bankName, explanation,
        updatedAt: newRecord.updatedAt, source: newRecord.source, answerSource: oldRecord.answerSource || oldRecord.source });
    }
    if (oldRecord.type === 'judge' && oldRecord.answerStatus === 'confirmed' && newRecord.answerStatus === 'confirmed' &&
      trustedAnswerProvenance(oldRecord) && !trustedAnswerProvenance(newRecord)) {
      // Re-observing the same answer without evidence cannot replace the
      // independently verified answer's provenance or its own option IDs.
      return normalizeRecord({ ...oldRecord, ...metadata, bankName: newRecord.bankName || oldRecord.bankName, explanation,
        updatedAt: newRecord.updatedAt, source: newRecord.source, answerSource: oldRecord.answerSource || oldRecord.source });
    }
    return normalizeRecord({ ...base, conflicts });
  }

  function upsert(recordsArray, incomingRecords) {
    if (!Array.isArray(recordsArray) || !Array.isArray(incomingRecords)) throw new Error('题库必须是数组');
    const records = new Map();
    const lastSeen = new Map();
    for (const [index, item] of [...recordsArray, ...incomingRecords].entries()) {
      const record = normalizeRecord(item);
      records.set(record.key, records.has(record.key) ? mergeNormalizedRecords(records.get(record.key), record) : record);
      lastSeen.set(record.key, index);
    }
    // Explicit aliases are produced only by content/batch repair. Ordinary
    // records with different IDs are still kept separate until that repair.
    const bankIdentity = bankResolver([...records.values()]);
    const signatures = new WeakMap();
    const signature = record => {
      if (!signatures.has(record)) signatures.set(record, contentSignature(record));
      return signatures.get(record);
    };
    const byBankAndId = new Map();
    const positions = new Map();
    for (const [index, record] of [...records.values()].entries()) {
      positions.set(record.key, index);
      if (!record.questionId) continue;
      const key = JSON.stringify([bankIdentity(record), record.questionId]);
      if (!byBankAndId.has(key)) byBankAndId.set(key, []);
      byBankAndId.get(key).push(record.key);
    }
    for (const target of [...records.values()].filter(record => record.questionIdAliases?.length > 1)) {
      if (!records.has(target.key)) continue;
      const queued = new Set(), knownAliases = new Set(), candidates = [];
      let cursor = -1;
      const enqueue = aliases => {
        for (const alias of aliases) {
          if (knownAliases.has(alias)) continue;
          knownAliases.add(alias);
          for (const key of byBankAndId.get(JSON.stringify([bankIdentity(target), alias])) || []) {
            if (key === target.key || queued.has(key) || positions.get(key) <= cursor) continue;
            queued.add(key);
            // Retain the old Map traversal order, including when a merged
            // record introduces further aliases during this pass.
            let low = 0, high = candidates.length;
            while (low < high) {
              const middle = (low + high) >>> 1;
              if (positions.get(candidates[middle]) < positions.get(key)) low = middle + 1;
              else high = middle;
            }
            candidates.splice(low, 0, key);
          }
        }
      };
      enqueue(records.get(target.key).questionIdAliases || []);
      while (candidates.length) {
        const key = candidates.shift();
        cursor = positions.get(key);
        const other = records.get(key);
        if (!other) continue;
        const current = records.get(target.key);
        if (signature(current) !== signature(other)) continue;
        if (current.contentOccurrence != null && other.contentOccurrence != null && current.contentOccurrence !== other.contentOccurrence) continue;
        const merged = foldEquivalent([current, other], { questionId: current.questionId, bankId: current.bankId, bankName: current.bankName, contentOccurrence: current.contentOccurrence });
        records.set(target.key, merged);
        records.delete(other.key);
        enqueue(merged.questionIdAliases || []);
      }
    }
    const repairedContents = new Set([...records.values()].filter(record => record.questionIdAliases?.length > 1)
      .map(record => JSON.stringify([bankIdentity(record), signature(record)])));
    for (const record of [...records.values()]) {
      if (record.questionId || record.contentOccurrence != null || record.answerStatus !== 'missing') continue;
      if (repairedContents.has(JSON.stringify([bankIdentity(record), signature(record)]))) records.delete(record.key);
    }
    // The saved DOM has no stable question ID. Upgrade it only when the complete
    // content and bank identify one unique server record in both directions.
    const anonymous = [...records.values()].filter((record) => !record.questionId);
    const identified = [...records.values()].filter((record) => record.questionId);
    const sameBank = (a, b) => {
      if (a.bankId && b.bankId) return a.bankId === b.bankId;
      if (!a.bankName || !b.bankName || a.bankName === '未命名题库' || b.bankName === '未命名题库') return false;
      return normalized(a.bankName) === normalized(b.bankName);
    };
    const possiblePair = (a, b) => a.options.length > 0 && b.options.length > 0 && sameBank(a, b) &&
      (a.contentOccurrence == null || b.contentOccurrence == null || a.contentOccurrence === b.contentOccurrence);
    const identifiedByContent = new Map();
    for (const record of identified) {
      const key = signature(record);
      if (!identifiedByContent.has(key)) identifiedByContent.set(key, []);
      identifiedByContent.get(key).push(record);
    }
    const candidates = new Map(), candidateCounts = new Map();
    for (const record of anonymous) {
      const matches = (identifiedByContent.get(signature(record)) || []).filter(other => possiblePair(record, other));
      candidates.set(record.key, matches);
      for (const match of matches) candidateCounts.set(match.key, (candidateCounts.get(match.key) || 0) + 1);
    }
    for (const record of anonymous) {
      const matches = candidates.get(record.key);
      if (matches.length !== 1) continue;
      const target = matches[0];
      if (candidateCounts.get(target.key) !== 1) continue;
      const promoted = normalizeRecord({ ...record, bankId: target.bankId, bankName: target.bankName, questionId: target.questionId });
      const currentTarget = records.get(target.key);
      const merged = lastSeen.get(record.key) < lastSeen.get(target.key) ? mergeNormalizedRecords(promoted, currentTarget) : mergeNormalizedRecords(currentTarget, promoted);
      records.set(target.key, merged);
      records.delete(record.key);
    }
    return [...records.values()];
  }

  function contentSignature(record) {
    return JSON.stringify([record.type, normalizedStem(record.stem), sorted(optionContents(record))]);
  }

  function bankResolver(records) {
    const namedIds = new Map();
    for (const record of records) if (record.bankId && record.bankName !== '未命名题库') {
      const name = normalized(record.bankName);
      if (!namedIds.has(name)) namedIds.set(name, new Set());
      namedIds.get(name).add(record.bankId);
    }
    return record => {
      if (record.bankId) return `id:${record.bankId}`;
      const name = normalized(record.bankName);
      if (!name || record.bankName === '未命名题库') return `unresolved:${record.key}`;
      const ids = namedIds.get(name);
      return ids?.size === 1 ? `id:${[...ids][0]}` : `name:${name}`;
    };
  }

  function foldEquivalent(group, identity = {}) {
    const existing = group.find(record => record.questionIdAliases?.length > 1);
    const first = existing || group.find(record => record.questionId) || group[0];
    const questionId = identity.questionId ?? first.questionId;
    const bankId = identity.bankId ?? (group.find(record => record.bankId)?.bankId || first.bankId);
    const bankName = identity.bankName || first.bankName;
    const ids = unique(group.flatMap(record => [record.questionId, ...(record.questionIdAliases || [])]).filter(Boolean));
    const meta = { bankId, bankName, questionId };
    if (ids.length > 1 || group.some(record => own(record, 'questionIdAliases'))) meta.questionIdAliases = ids;
    const occurrence = identity.contentOccurrence ?? first.contentOccurrence ?? group.find(record => record.contentOccurrence != null)?.contentOccurrence;
    if (occurrence != null) meta.contentOccurrence = occurrence;
    // Process missing observations first so the selected options and the answer
    // IDs always come together from an answer-bearing record.
    const ordered = group.filter(record => record.answerStatus === 'missing').concat(group.filter(record => record.answerStatus !== 'missing'));
    if (group.length === 1 && first.bankId === meta.bankId && first.bankName === meta.bankName && first.questionId === meta.questionId &&
      (meta.contentOccurrence == null || meta.contentOccurrence === first.contentOccurrence) &&
      (!own(meta, 'questionIdAliases') || JSON.stringify(meta.questionIdAliases) === JSON.stringify(first.questionIdAliases))) return first;
    let result;
    for (const record of ordered) {
      const rebased = normalizeRecord({ ...record, ...meta });
      result = result ? mergeNormalizedRecords(result, rebased) : rebased;
    }
    return result;
  }

  function compactRecords(input) {
    if (!Array.isArray(input)) throw new Error('题库必须是数组');
    const entries = input.map((value, index) => ({ record: normalizeRecord(value), index, batch: '', occurrence: null }));
    const bankIdentity = bankResolver(entries.map(entry => entry.record));
    const listSource = record => [record.answerSource, record.source].find(source => source?.kind === 'network' &&
      /\/(?:upm\/(?:wrong\/)?start|pra\/[^/]+\/questions)\/?$/u.test(source.url || '') && Number.isFinite(Date.parse(source.observedAt)));
    const legacySources = new Map();
    for (const entry of entries) {
      const record = entry.record;
      entry.signature = contentSignature(record);
      entry.bank = bankIdentity(record);
      if (record.contentOccurrence != null) entry.occurrence = record.contentOccurrence;
      const explicit = record.source.batchId || record.answerSource?.batchId;
      if (explicit) entry.batch = `${entry.bank}:${explicit}`;
      else if (entry.occurrence == null) {
        const source = listSource(record);
        if (!source) continue;
        const key = JSON.stringify([entry.bank, source.url]);
        if (!legacySources.has(key)) legacySources.set(key, []);
        legacySources.get(key).push({ entry, time: Date.parse(source.observedAt) });
      }
    }
    // Older versions timestamped individual rows inside each list response.
    // Infer only network list-response clusters; DOM/answer observations are
    // never assumed to be full snapshots. Their original order gives duplicate
    // occurrence numbers and keeps legitimate repeated questions in each list.
    for (const [key, items] of legacySources) {
      items.sort((a, b) => a.time - b.time || a.entry.index - b.entry.index);
      let previous = -Infinity, batch = '';
      for (const item of items) {
        if (item.time - previous > 1000) batch = `legacy:${key}:${item.time}`;
        item.entry.batch = batch; previous = item.time;
      }
    }
    const counters = new Map();
    for (const entry of entries) {
      if (!entry.batch || entry.occurrence != null) continue;
      const key = JSON.stringify([entry.batch, entry.signature]);
      entry.occurrence = counters.get(key) || 0;
      counters.set(key, entry.occurrence + 1);
    }
    const groups = new Map();
    const byContent = new Map();
    const byContentAlias = new Map();
    const indexAliases = (key, entry) => {
      if (!byContentAlias.has(entry.content)) byContentAlias.set(entry.content, new Map());
      const aliases = byContentAlias.get(entry.content);
      for (const id of [entry.record.questionId, ...(entry.record.questionIdAliases || [])]) {
        if (!id) continue;
        if (!aliases.has(id)) aliases.set(id, new Set());
        aliases.get(id).add(key);
      }
    };
    const add = (key, entry) => {
      if (!groups.has(key)) groups.set(key, []);
      groups.get(key).push(entry);
    };
    for (const entry of entries) {
      const content = JSON.stringify([entry.bank, entry.signature]);
      entry.content = content;
      if (entry.occurrence == null || entry.record.options.length < 2 || entry.record.type === 'unknown') continue;
      const key = JSON.stringify([content, entry.occurrence]);
      add(key, entry);
      if (!byContent.has(content)) byContent.set(content, new Set());
      byContent.get(content).add(key);
      indexAliases(key, entry);
    }
    for (const entry of entries) {
      if (entry.occurrence != null && entry.record.options.length >= 2 && entry.record.type !== 'unknown') continue;
      const matches = byContent.get(entry.content);
      let key;
      const matchingAlias = byContentAlias.get(entry.content)?.get(entry.record.questionId);
      if (entry.record.questionId && matchingAlias?.size === 1) key = matchingAlias.values().next().value;
      else if (matches?.size === 1) key = matches.values().next().value;
      else if (matches?.size > 1 && !entry.record.questionId && entry.record.answerStatus === 'missing') continue;
      else key = `unresolved:${entry.record.key}`;
      add(key, entry);
      if (matches?.has(key)) indexAliases(key, entry);
    }
    const records = [];
    let duplicateGroups = 0;
    for (const group of groups.values()) {
      if (group.length > 1) duplicateGroups++;
      const identity = {};
      const occurrence = group.find(entry => entry.occurrence != null)?.occurrence;
      if (occurrence != null) identity.contentOccurrence = occurrence;
      records.push(foldEquivalent(group.map(entry => entry.record), identity));
    }
    return { records, removed: input.length - records.length, groups: duplicateGroups, conflictCount: records.filter(record => record.answerStatus === 'conflict').length };
  }

  function bigrams(value) {
    const chars = Array.from(value);
    if (chars.length < 2) return new Set(chars);
    return new Set(chars.slice(0, -1).map((char, index) => char + chars[index + 1]));
  }

  function search(records, query, { limit = 8, field = 'all', offset = 0 } = {}) {
    const queryText = clean(query).replace(/^(?:第\s*\d+\s*题[\s、.．:：]*|\d+\s*[、．]\s*|\d+\.\s+)/u, '');
    const needle = normalized(queryText);
    if (needle.length < 2) return [];
    const selectedField = ['all', 'stem', 'options', 'answer'].includes(field) ? field : 'all';
    const terms = unique(queryText.split(/\s+/u).map(normalized).filter(Boolean));
    const queryGrams = bigrams(needle);
    const result = [];
    for (const record of records) {
      const haystack = normalizedStem(record.stem);
      // Each option/answer stays a separate searchable segment. Joining option A
      // and option B would create phrases that never existed in either option.
      const fields = {
        stem: [haystack],
        options: (record.options || []).map((option) => normalized(option.text)),
        answer: record.answerStatus === 'confirmed' ? (record.answerTexts || []).map(normalized) : [],
      };
      const allowed = selectedField === 'all' ? ['stem', 'options', 'answer'] : [selectedField];
      let match, score = 0, matchedField;
      const prefer = (candidateField, candidateScore, candidateMatch = 'partial') => {
        if (candidateScore > score) { matchedField = candidateField; score = candidateScore; match = candidateMatch; }
      };
      if (allowed.includes('stem')) {
        if (haystack === needle) prefer('stem', 1, 'exact');
        else if (haystack.includes(needle)) prefer('stem', 0.86 + 0.08 * needle.length / haystack.length);
      }
      for (const candidateField of ['options', 'answer']) {
        if (!allowed.includes(candidateField)) continue;
        const matching = fields[candidateField].filter((segment) => segment.includes(needle));
        if (matching.length) {
          const coverage = Math.max(...matching.map((segment) => needle.length / segment.length));
          prefer(candidateField, (candidateField === 'options' ? 0.72 : 0.60) + 0.06 * coverage);
        }
      }
      if (terms.length > 1) {
        const allIn = (names) => terms.every((term) => names.some((name) => fields[name].some((segment) => segment.includes(term))));
        if (allIn(allowed)) {
          if (allowed.includes('stem') && allIn(['stem'])) prefer('stem', 0.82);
          else if (allowed.includes('options') && allIn(['options'])) prefer('options', 0.70);
          else if (allowed.includes('answer') && allIn(['answer'])) prefer('answer', 0.58);
          else {
            // Cross-field AND is available only with the explicit all-fields scope.
            const firstField = allowed.find((name) => terms.some((term) => fields[name].some((segment) => segment.includes(term))));
            prefer(firstField, firstField === 'stem' ? 0.80 : firstField === 'options' ? 0.68 : 0.56);
          }
        }
      }
      if (!match && allowed.includes('stem') && needle.length >= 4 && terms.length === 1) {
        const grams = bigrams(haystack);
        const intersection = [...queryGrams].filter((gram) => grams.has(gram)).length;
        const similarity = 2 * intersection / (queryGrams.size + grams.size || 1);
        if (similarity >= 0.45) prefer('stem', similarity * 0.50, 'similar');
      }
      if (match) result.push({ record, match, score, matchedField });
    }
    const stableKey = (record) => JSON.stringify([record.bankId || '', record.bankName || '', record.questionId || '', record.key || '']);
    result.sort((a, b) => b.score - a.score || a.record.stem.localeCompare(b.record.stem, 'zh-CN') || stableKey(a.record).localeCompare(stableKey(b.record), 'zh-CN'));
    const start = Math.max(0, Math.floor(Number(offset) || 0));
    const count = Math.max(0, Math.min(100, Math.floor(Number(limit) || 0)));
    return result.slice(start, start + count);
  }

  function mapAnswers(recordInput, currentInput) {
    let record, current;
    try { record = normalizeRecord(recordInput); current = normalizeRecord(currentInput); }
    catch (_) { return { status: 'unmapped', labels: [], answerTexts: [] }; }
    const answerTexts = [...record.answerTexts];
    const result = (status, labels = []) => ({ status, labels, answerTexts });
    if (record.answerStatus === 'conflict') return result('ambiguous');
    if (record.answerStatus !== 'confirmed' || !answerTexts.length) return result('unmapped');
    if (normalizedStem(record.stem) !== normalizedStem(current.stem) ||
      (record.type !== 'unknown' && current.type !== 'unknown' && record.type !== current.type)) return result('unmapped');
    if (record.options.length && !sameArray(optionContents(record), current.options.map((option) => comparableAnswer(option.text, record.type)))) return result('unmapped');
    const completeIdentity = record.type === current.type && record.type !== 'unknown' && record.options.length > 0 &&
      record.options.length === current.options.length && record.correctOptionIds.length > 0 &&
      record.options.every(option => option.id) && current.options.every(option => option.id) &&
      new Set(record.options.map(option => option.id)).size === record.options.length &&
      new Set(current.options.map(option => option.id)).size === current.options.length &&
      sameArray(record.options.map(option => JSON.stringify([option.id, comparableAnswer(option.text, record.type)])),
        current.options.map(option => JSON.stringify([option.id, comparableAnswer(option.text, record.type)])));
    if (completeIdentity) {
      const selected = record.correctOptionIds.map(id => current.options.find(option => option.id === id));
      if (selected.some(option => !option)) return result('unmapped');
      if (unique(current.options.map(option => option.label)).length !== current.options.length) return result('ambiguous');
      return result('matched', selected.map(option => option.label));
    }
    const labels = [];
    for (const value of answerTexts) {
      const expected = comparableAnswer(value, record.type);
      const candidates = current.options.filter((option) => comparableAnswer(option.text, record.type) === expected);
      if (!candidates.length) return result('unmapped');
      const originalCorrect = record.options.filter((option) => record.correctOptionIds.includes(option.id) && comparableAnswer(option.text, record.type) === expected);
      for (const original of originalCorrect) {
        const idCandidates = original.id ? current.options.filter((option) => option.id === original.id) : [];
        if (idCandidates.length > 1) return result('ambiguous');
        if (idCandidates.length === 1 && comparableAnswer(idCandidates[0].text, record.type) !== expected) return result('unmapped');
      }
      if (candidates.length > 1) {
        const originalGroup = record.options.filter((option) => comparableAnswer(option.text, record.type) === expected);
        // Repeated text is safe only when every occurrence is explicitly correct.
        if (record.type !== 'multiple' || originalCorrect.length !== originalGroup.length || originalCorrect.length !== candidates.length) return result('ambiguous');
        labels.push(...candidates.map((option) => option.label));
      } else labels.push(candidates[0].label);
    }
    if (unique(labels).length !== labels.length) return result('ambiguous');
    return result('matched', labels);
  }

  function csvSafe(value) {
    const result = text(value);
    // CSV quoting alone does not stop spreadsheet formula evaluation or long-ID rounding.
    return /^(?:\s*[=+\-@]|[\t\r]|\d{16,}$)/u.test(result) ? `'${result}` : result;
  }

  function csvRestore(value) {
    return value.startsWith("'") && csvSafe(value.slice(1)) === value ? value.slice(1) : value;
  }

  function csvCell(value) { return `"${csvSafe(value).replace(/"/g, '""')}"`; }

  function toCSV(records) {
    const canonical = records.map(normalizeRecord);
    const optionCount = Math.max(0, ...canonical.map((record) => record.options.length));
    const optionNames = Array.from({ length: optionCount }, (_, index) => `选项${index < 26 ? String.fromCharCode(65 + index) : index + 1}`);
    const headers = ['来源题库', '题库ID', '题目ID', '题型', '题干', ...optionNames, '正确答案内容', '采集时答案字母', '解析', '答案状态', '答案来源', '采集时间', '完整记录JSON'];
    const rows = [headers];
    for (const record of canonical) {
      const mapped = mapAnswers(record, record);
      rows.push([record.bankName, record.bankId, record.questionId, TYPE_NAMES[record.type], record.stem,
        ...Array.from({ length: optionCount }, (_, index) => record.options[index]?.text || ''),
        record.answerTexts.join('\n'), mapped.status === 'matched' ? mapped.labels.join(',') : '', record.explanation,
        STATUS_NAMES[record.answerStatus], record.answerSource?.kind || record.source.kind, record.answerSource?.observedAt || record.source.observedAt, JSON.stringify(record)]);
    }
    return '\uFEFF' + rows.map((row) => row.map(csvCell).join(',')).join('\r\n') + '\r\n';
  }

  function parseCSV(input) {
    if (typeof input !== 'string') throw new Error('CSV内容必须是文字');
    const value = input.replace(/^\uFEFF/, '');
    const rows = [];
    let row = [], cell = '', quoted = false, closed = false;
    const finishCell = () => { row.push(cell); cell = ''; closed = false; };
    const finishRow = () => { finishCell(); if (row.some((item) => item !== '')) rows.push(row); row = []; };
    for (let index = 0; index < value.length; index += 1) {
      const char = value[index];
      if (quoted) {
        if (char === '"') {
          if (value[index + 1] === '"') { cell += '"'; index += 1; }
          else { quoted = false; closed = true; }
        } else cell += char;
      } else if (char === ',') finishCell();
      else if (char === '\n' || char === '\r') { finishRow(); if (char === '\r' && value[index + 1] === '\n') index += 1; }
      else if (char === '"') {
        if (cell || closed) throw new Error('CSV引号位置错误');
        quoted = true;
      } else {
        if (closed) throw new Error('CSV引号后包含非法字符');
        cell += char;
      }
    }
    if (quoted) throw new Error('CSV存在未闭合引号');
    if (cell || row.length || closed) finishRow();
    return rows;
  }

  function importedArray(value, type, options) {
    const trimmed = clean(value);
    if (!trimmed) return [];
    if (trimmed.startsWith('[')) {
      let result;
      try { result = JSON.parse(trimmed); } catch (_) { throw new Error('正确答案内容JSON格式错误'); }
      return stringArray(result, '正确答案内容');
    }
    if (type !== 'multiple' || options.some((option) => comparableAnswer(option.text, type) === comparableAnswer(trimmed, type))) return [trimmed];
    const answers = trimmed.split(/\r?\n/).map(clean).filter(Boolean);
    if (answers.some((answer) => !options.some((option) => comparableAnswer(option.text, type) === comparableAnswer(answer, type)))) throw new Error('多选答案请使用JSON数组，或每行填写一个完整选项内容');
    return answers;
  }

  function fromCSV(value) {
    const rows = parseCSV(value);
    if (!rows.length) throw new Error('CSV为空');
    const headers = rows.shift().map((item) => clean(csvRestore(item)));
    if (unique(headers).length !== headers.length) throw new Error('CSV存在重复列名');
    if (!headers.includes('完整记录JSON') && (!headers.includes('题干') || !headers.includes('题型'))) throw new Error('CSV需要“题干、题型”列或“完整记录JSON”列');
    const typeAliases = { ...Object.fromEntries(Object.entries(TYPE_NAMES).map(([key, name]) => [name, key])), 单选: 'single', 多选: 'multiple', 判断: 'judge', single: 'single', multiple: 'multiple', judge: 'judge', unknown: 'unknown' };
    const statusAliases = { ...Object.fromEntries(Object.entries(STATUS_NAMES).map(([key, name]) => [name, key])), confirmed: 'confirmed', missing: 'missing', conflict: 'conflict', 无答案: 'missing', 待核验: 'missing' };
    const records = [];
    for (let index = 0; index < rows.length; index += 1) {
      const cells = rows[index];
      try {
        if (cells.length !== headers.length) throw new Error(`列数应为${headers.length}，实际为${cells.length}`);
        const row = Object.fromEntries(headers.map((header, column) => [header, csvRestore(cells[column])]));
        if (clean(row['完整记录JSON'])) {
          let raw;
          try { raw = JSON.parse(row['完整记录JSON']); } catch (_) { throw new Error('完整记录JSON格式错误'); }
          records.push(normalizeRecord(raw));
          continue;
        }
        const type = typeAliases[clean(row['题型'])];
        if (!type) throw new Error('题型必须为单选题、多选题、判断题或未知');
        const options = headers.filter((header) => /^选项(?:[A-Z]+|\d+)$/u.test(header) && clean(row[header])).map((header) => ({ id: '', label: header.slice(2), text: row[header] }));
        const answers = importedArray(row['正确答案内容'], type, options);
        const statusText = clean(row['答案状态']);
        if (statusText && !own(statusAliases, statusText)) throw new Error('无效答案状态');
        const answerStatus = statusText ? statusAliases[statusText] : answers.length ? 'confirmed' : 'missing';
        const record = normalizeRecord({ bankId: row['题库ID'], bankName: row['来源题库'], questionId: row['题目ID'], type,
          stem: row['题干'], options, answerTexts: answers, answerStatus, explanation: row['解析'],
          source: { kind: clean(row['答案来源']) || 'csv-import', observedAt: row['采集时间'] } });
        if (record.answerStatus === 'confirmed' && record.options.length && mapAnswers(record, record).status !== 'matched') throw new Error('正确答案内容不能唯一对应选项');
        records.push(record);
      } catch (error) { throw new Error(`CSV第${index + 2}行：${error.message}`); }
    }
    return records;
  }

  return { normalizeRecord, repairLegacyJudgeAnswers, repairDuplicateOptionConflicts, upgradeLegacyImageRecords, upgradeLegacyMathEntities, mergeRecord, upsert, compactRecords, search, mapAnswers, toCSV, fromCSV };
})();

if (typeof module !== 'undefined' && module.exports) module.exports = QBCore;


// ---- src/adapter.js ----
/* Site adapter: observe existing practice responses; never submit or alter answers. */
const QBAdapter = (() => {
  'use strict';
  const TYPES = { 0: 'single', 1: 'multiple', 2: 'judge' };
  const ROOT_SELECTOR = '.yxtulcdsdk-pc-marking-main';
  const MAX_RESPONSE = 8 * 1024 * 1024;
  const has = (obj, key) => Object.prototype.hasOwnProperty.call(obj, key);
  const ENTITIES = { nbsp: ' ', lt: '<', LT: '<', gt: '>', GT: '>', amp: '&', AMP: '&', quot: '"', QUOT: '"', apos: "'",
    colon: ':', sol: '/', copy: '©', reg: '®', times: '×', divide: '÷', plusmn: '±', le: '≤', ge: '≥', ne: '≠', deg: '°', micro: 'µ' };
  let entityDecoder = null;
  const decodeEntities = value => value.replace(/&(#x[0-9a-f]+|#\d+|[a-z][a-z0-9]*);/gi, (entity, name) => {
    if (name[0] !== '#') {
      if (has(ENTITIES, name)) return ENTITIES[name];
      // Only an entity token reaches this detached textarea; no markup is inserted.
      try {
        if (typeof document !== 'undefined' && document.createElement) {
          entityDecoder ||= document.createElement('textarea');
          entityDecoder.innerHTML = entity;
          return entityDecoder.value;
        }
      } catch (_) { /* A restrictive page may disable DOM entity decoding. */ }
      return entity;
    }
    const code = name[1].toLowerCase() === 'x' ? parseInt(name.slice(2), 16) : Number(name.slice(1));
    return code > 0 && code <= 0x10ffff && (code < 0xd800 || code > 0xdfff) ? String.fromCodePoint(code) : '';
  });

  function imageMarker(tag) {
    const attributes = tag.replace(/^<img(?=[\s/>])/i, '').replace(/>$/, '');
    const attribute = /([^\s"'<>\/=]+)(?:\s*=\s*(?:"([^"]*)"|'([^']*)'|([^\s>]+)))?/g;
    let match;
    while ((match = attribute.exec(attributes))) {
      if (match[1].toLowerCase() !== 'src') continue;
      const value = decodeEntities(match[2] ?? match[3] ?? match[4] ?? '').trim();
      if (!/^https?:\/\//i.test(value)) return '';
      try {
        const url = new URL(value);
        if (!['http:', 'https:'].includes(url.protocol) || url.username || url.password) return '';
        return `[图片:${url.href.replace(/\[/g, '%5B').replace(/\]/g, '%5D')}]`;
      } catch (_) { return ''; }
    }
    return '';
  }

  function richText(value) {
    // DOM and response HTML must retain the same src, never a responsive currentSrc.
    if (value && typeof value === 'object') value = typeof value.innerHTML === 'string' ? value.innerHTML : value.textContent;
    const html = String(value == null ? '' : value)
      .replace(/<(script|style)(?=[\s/>])(?:[^"'<>]|"[^"]*"|'[^']*')*>[\s\S]*?<\/\1\s*>/gi, '');
    const tags = /<!--[\s\S]*?-->|<\/?[a-z][\w:-]*(?:[^"'<>]|"[^"]*"|'[^']*')*>/gi;
    let result = '', end = 0, match;
    while ((match = tags.exec(html))) {
      result += decodeEntities(html.slice(end, match.index));
      if (/^<img(?=[\s/>])/i.test(match[0])) result += imageMarker(match[0]);
      else if (/^<br(?=[\s/>])/i.test(match[0])) result += '\n';
      end = tags.lastIndex;
    }
    return (result + decodeEntities(html.slice(end))).replace(/\u00a0/g, ' ').trim();
  }
  const text = richText;
  const flat = value => String(value == null ? '' : value).replace(/\s+/g, '');
  const idString = value => typeof value === 'string' || Number.isSafeInteger(value) ? String(value) : '';
  const signature = q => [q.type, flat(q.stem), (q.options || []).map(o => flat(o.text)).sort().join('\u001f')].join('\u001e');
  const labelFor = index => String.fromCharCode(65 + index);

  function standardAnswer(node, type, options, context) {
    const result = node.resultInfo && typeof node.resultInfo === 'object' ? node.resultInfo : null;
    const answerNode = result || node;
    if (context.hideStandardAnswers || [node, answerNode].some(value => value.allowViewSingleQuesAnswer === false || value.allowViewSingleQuesAnswer === 0)) {
      return { correctOptionIds: [], answerTexts: [], answerStatus: 'missing' };
    }
    const hasSubmitted = Array.isArray(node.submitQuesAnswers) && node.submitQuesAnswers.length > 0;
    const verifiedResponse = context.answerResponse && context.questionId && context.knownQuestion;
    const evidence = verifiedResponse ? 'answer-response' : hasSubmitted || result ? 'submitted-list' : 'explicit-standard';
    if (context.answerResponse && !verifiedResponse) return { correctOptionIds: [], answerTexts: [], answerStatus: 'missing' };
    if (type === 'judge') {
      // /upm/start sends judgeAnswer=0 for unanswered listQues as well. The
      // real client creates resultInfo only for non-empty submitQuesAnswers;
      // reading that placeholder as an answer silently labels every new item false.
      if ((context.practiceList || context.collection === 'listQues') && !hasSubmitted && !result && !verifiedResponse) {
        return { correctOptionIds: [], answerTexts: [], answerStatus: 'missing' };
      }
      const raw = answerNode.judgeAnswer;
      if (raw === 0 || raw === '0' || raw === 1 || raw === '1') {
        const value = String(raw);
        return { correctOptionIds: [value], answerTexts: [value === '1' ? '正确' : '错误'], answerStatus: 'confirmed', answerEvidence: evidence };
      }
    } else {
      let ids = [];
      if (Array.isArray(node.correctAnswers)) ids = node.correctAnswers.map(idString).filter(Boolean);
      else if (result && Array.isArray(result.answers)) ids = result.answers.map(idString).filter(Boolean);
      else if (context.answerResponse && Array.isArray(node.answers)) ids = node.answers.map(idString).filter(Boolean);
      else if (Array.isArray(node.choiceItems)) ids = node.choiceItems.filter(o => o.answer === 1).map(o => idString(o.id));
      ids = [...new Set(ids)].filter(Boolean);
      const resolved = ids.map(id => options.filter(o => o.id === id));
      if (ids.length && resolved.every(matches => matches.length === 1) && (type !== 'single' || ids.length === 1)) {
        return { correctOptionIds: ids, answerTexts: resolved.map(matches => matches[0].text), answerStatus: 'confirmed', answerEvidence: evidence };
      }
    }
    return { correctOptionIds: [], answerTexts: [], answerStatus: 'missing' };
  }

  function knownById(context, id) {
    if (!id || !context.knownQuestions) return null;
    const values = context.knownQuestions instanceof Map ? [...context.knownQuestions.values()] : context.knownQuestions;
    if (!Array.isArray(values)) return null;
    const matches = values.filter(q => q.questionId === id && (!context.bankId || !q.bankId || q.bankId === context.bankId));
    return matches.length === 1 ? matches[0] : null;
  }

  function recordFromNode(node, context) {
    const rawType = has(node, 'quesType') ? node.quesType : node.type;
    let type = TYPES[rawType];
    // The practice client submits listQues[i].id as answers[].quesId. A
    // single-answer response may have its own receipt ID, so its request wins.
    const id = idString((context.answerResponse && context.questionId) ||
      (context.collection === 'listQues' && node.id) || node.quesId || node.questionId || node.id || context.questionId);
    const previous = knownById(context, id);
    if (!type && previous) type = previous.type;
    if (!type) return null;
    let stem = text(node.content);
    if (!stem && previous) stem = previous.stem;
    if (!stem || stem.length > 100000) return null;
    if (context.answerResponse && previous && (type !== previous.type || flat(stem) !== flat(previous.stem))) return null;
    // Do not treat an arbitrary content/type business object as a question.
    if (!previous && !has(node, 'quesType') && !Array.isArray(node.choiceItems) && !has(node, 'judgeAnswer')) return null;
    let options;
    if (type === 'judge') {
      options = [{ id: '1', text: '正确', label: '正确' }, { id: '0', text: '错误', label: '错误' }];
    } else if (Array.isArray(node.choiceItems)) {
      if (node.choiceItems.some(option => !option || typeof option !== 'object')) return null;
      options = node.choiceItems.slice(0, 100).map((option, index) => ({
        id: idString(option.id), text: text(option.itemContent) || text(option.content), label: labelFor(index)
      }));
      if (options.length < 2 || options.some(o => !o.text)) return null;
    } else if (previous) options = previous.options.map(o => ({ ...o }));
    else return null;
    const answers = standardAnswer(node, type, options, { ...context, knownQuestion: previous });
    const record = {
      bankId: idString(node.praId || context.bankId || (previous && previous.bankId)),
      bankName: text(context.bankName || (previous && previous.bankName)), questionId: id,
      type, stem, options, ...answers,
      explanation: text((node.resultInfo && node.resultInfo.explainText) || node.explainText),
      source: { kind: context.kind || 'network', url: String(context.url || ''), observedAt: context.observedAt || new Date().toISOString(),
        ...(context.batchId ? { batchId: context.batchId } : {}) }
    };
    if (context.answerResponse && previous) {
      if (Number.isSafeInteger(previous.questionIndex)) record.questionIndex = previous.questionIndex;
      if (Number.isSafeInteger(previous.contentOccurrence)) record.contentOccurrence = previous.contentOccurrence;
      if (previous.source?.batchId) record.source.batchId = previous.source.batchId;
    } else if (context.fullList && has(node, 'content')) record._fullList = true;
    return record;
  }

  function extractQuestions(payload, context = {}) {
    context = { ...context, observedAt: context.observedAt || new Date().toISOString() };
    const output = [];
    const visited = new WeakSet();
    let count = 0;
    const childKeys = ['data', 'result', 'listQues', 'questionList', 'questions', 'subQuesList', 'list', 'items'];
    function visit(node, inherited, depth) {
      if (!node || typeof node !== 'object' || depth > 12 || ++count > 16000 || visited.has(node)) return;
      visited.add(node);
      if (Array.isArray(node)) {
        const arrayContext = inherited.answerResponse && node.length !== 1 ? { ...inherited, questionId: '' } : inherited;
        for (const item of node.slice(0, 10000)) visit(item, arrayContext, depth + 1);
        return;
      }
      const hidden = inherited.hideStandardAnswers || [node, node.info].some(value => value &&
        (value.allowViewSingleQuesAnswer === false || value.allowViewSingleQuesAnswer === 0));
      const next = { ...inherited, hideStandardAnswers: Boolean(hidden), bankId: idString(node.praId || inherited.bankId), bankName: text(node.praName || inherited.bankName) };
      const isListContainer = ['listQues', 'questionList', 'questions'].some(key => Array.isArray(node[key]));
      const candidate = isListContainer ? null : recordFromNode(node, next);
      if (candidate) output.push(candidate);
      for (const key of childKeys) if (has(node, key)) {
        const list = ['listQues', 'questionList', 'questions'].includes(key) && Array.isArray(node[key]) && !next.answerResponse;
        visit(node[key], list ? { ...next, fullList: true, collection: key } : next, depth + 1);
      }
    }
    visit(payload, context, 0);
    const unique = new Map();
    for (const q of output) {
      const key = `${q.bankId}\u001f${q.questionId || signature(q)}`;
      const old = unique.get(key);
      if (!old || (old.answerStatus === 'missing' && q.answerStatus === 'confirmed')) unique.set(key, q);
    }
    const records = [...unique.values()];
    let questionIndex = 0;
    const occurrences = new Map();
    for (const record of records) {
      if (!record._fullList) continue;
      delete record._fullList;
      const contentKey = `${record.bankId}\u001f${signature(record)}`;
      record.questionIndex = questionIndex++;
      record.contentOccurrence = occurrences.get(contentKey) || 0;
      occurrences.set(contentKey, record.contentOccurrence + 1);
    }
    return records;
  }

  function classifyURL(value, base) {
    try {
      const url = new URL(value, base);
      const host = url.hostname;
      const allowed = host === 'www.shhuayi-elearning.cn' || host === 'shhuayi-elearning.cn' ||
        /(^|\.)(yunxuetang\.cn|yxt\.com)$/.test(host) || url.origin === new URL(base).origin;
      if (!allowed) return null;
      const path = url.pathname;
      const list = /\/(?:upm\/(?:wrong\/)?start|pra\/[^/]+\/questions)\/?$/.test(path);
      const answerMatch = path.match(/\/upm\/([^/]+)\/users\/[^/]+\/(?:wrong\/)?answer\/?$/);
      if (!list && !answerMatch) return null;
      const praMatch = path.match(/\/pra\/([^/]+)\/questions/);
      return {
        // Retain no token-bearing query parameters in saved source URLs.
        url: url.origin + url.pathname.replace(/\/users\/[^/]+(?=\/)/, '/users/_'),
        bankId: url.searchParams.get('praId') || (answerMatch && answerMatch[1]) || (praMatch && praMatch[1]) || '',
        answerResponse: Boolean(answerMatch),
        practiceList: /\/upm\/(?:wrong\/)?start\/?$/.test(path)
      };
    } catch (_) { return null; }
  }

  function requestQuestionId(body) {
    try {
      if (typeof body !== 'string' || body.length > 1024 * 1024) return '';
      const value = JSON.parse(body);
      return Array.isArray(value.answers) && value.answers.length === 1 ? idString(value.answers[0].quesId) : '';
    } catch (_) { return ''; }
  }

  function responseQuestionCount(payload) {
    const visited = new WeakSet();
    function countItems(items) {
      let total = 0;
      for (const node of items) {
        if (!node || typeof node !== 'object') return null;
        const type = Number(has(node, 'quesType') ? node.quesType : node.type);
        if ([0, 1, 2, 3, 4].includes(type) && has(node, 'content')) total++;
        else if (type === 5 && Array.isArray(node.subQuesList)) {
          const children = countItems(node.subQuesList);
          if (children === null) return null;
          total += children;
        } else return null;
      }
      return total <= 100000 ? total : null;
    }
    function find(node, depth) {
      if (!node || typeof node !== 'object' || depth > 8 || visited.has(node)) return null;
      visited.add(node);
      for (const key of ['listQues', 'questionList']) if (Array.isArray(node[key])) return countItems(node[key]);
      for (const key of ['data', 'result']) if (node[key]) {
        const count = find(node[key], depth + 1);
        if (count !== null) return count;
      }
      return null;
    }
    return find(payload, 0);
  }

  function create({ window: win, document: doc, onQuestions = () => {}, onStatus = () => {}, onBankChange = () => {}, observeNetwork = true }) {
    let active = false;
    let copyEnabled = false;
    let observer = null;
    let timer = null;
    let copyStyle = null;
    let fetchOriginal = null;
    let fetchWrapped = null;
    let xhrOpenOriginal = null;
    let xhrSendOriginal = null;
    let xhrOpenWrapped = null;
    let xhrSendWrapped = null;
    let lastDOMSignature = '';
    let networkGeneration = 0;
    let requestSequence = 0;
    let batchSequence = 0;
    const known = new Map();
    let knownContentIndex = null;
    const xhrContext = new WeakMap();
    const pendingXHR = new Set();
    const banksById = new Map();
    const banksByTask = new Map();
    const knownSnapshotOrder = new Map();
    const deferredSnapshots = new Map();
    let currentBank = null;
    let pendingSelection = '';
    let blockedForm = null;
    let lastFormSnapshot = null;
    let bankListeners = false;
    const status = message => { try { onStatus(message); } catch (_) { /* UI callbacks must not affect the page. */ } };
    const locationURL = () => String(win.location && win.location.href || '');

    function isSupportedPage() {
      try {
        const host = new URL(locationURL()).hostname;
        if (host === 'www.shhuayi-elearning.cn' || host === 'shhuayi-elearning.cn') return true;
      } catch (_) { /* An incomplete location still allows an explicit exercise root. */ }
      return Boolean(doc.querySelector(ROOT_SELECTOR));
    }

    function formSnapshot() {
      const element = [...doc.querySelectorAll(`${ROOT_SELECTOR} .yxtulcdsdk-form`)].find(visible);
      return element ? { element, text: flat(text(element)) } : null;
    }

    function taskFromURL() {
      try {
        const url = new URL(locationURL());
        const hashQuery = url.hash.includes('?') ? url.hash.slice(url.hash.indexOf('?') + 1) : '';
        return new URLSearchParams(hashQuery).get('taskId') || url.searchParams.get('taskId') || '';
      } catch (_) { return ''; }
    }

    function displayedQuestionCount() {
      const progress = doc.querySelector('.yxtulcdsdk-answer-card__top');
      const match = progress && visible(progress) && text(progress.textContent).match(/(\d+)\s*\/\s*(\d+)(?!\d)/);
      if (match) {
        const done = Number(match[1]), total = Number(match[2]);
        if (total >= 0 && total <= 100000 && done <= total) return total;
      }
      const preview = [...doc.querySelectorAll('.yxtulcdsdk-uexam-preview-content__base-row-flex--practice .info-left .info-text')]
        .filter(visible).map(node => text(node.textContent).match(/^试题总数\s*[：:]\s*(\d+)\s*题$/)).filter(Boolean);
      if (preview.length !== 1) return null;
      const total = Number(preview[0][1]);
      return total >= 0 && total <= 100000 ? total : null;
    }

    function bankDOM() {
      const selected = doc.querySelector('.task-content-active .group-title, .task-content-active .task-content-color-active');
      const selectedName = text(selected?.textContent);
      if (pendingSelection && flat(pendingSelection) === flat(selectedName)) pendingSelection = '';
      const sidebarName = pendingSelection || selectedName;
      const playerName = text(doc.querySelector('header.o2oPlayFrame-right .title .yxtf-tooltip')?.textContent);
      const examName = text(doc.querySelector('.yxtulcdsdk-exam-header .yxtf-tooltip')?.textContent);
      const container = doc.querySelector('.yxtulcdsdk-exam-container[task-id]');
      const containerTask = idString(container?.getAttribute('task-id'));
      const routeTask = taskFromURL();
      const selectedTask = idString(selected?.closest('.task-content-active')?.getAttribute('data-task-id'));
      const pending = pendingSelection && flat(pendingSelection) !== flat(selectedName);
      const taskId = pending ? '' : selectedTask || routeTask || containerTask;
      const bankName = text(sidebarName || playerName || examName || String(doc.title || '').replace(/ - 华谊集团$/, ''));
      const mismatch = Boolean(pending || (sidebarName && playerName && flat(sidebarName) !== flat(playerName)) ||
        (sidebarName && examName && flat(sidebarName) !== flat(examName)) ||
        (playerName && examName && flat(playerName) !== flat(examName)) ||
        (routeTask && containerTask && routeTask !== containerTask));
      return { bankName, taskId, mismatch };
    }

    function syncBank() {
      if (!isSupportedPage()) {
        const empty = { bankId: '', bankName: '', taskId: '', loading: false, questionCount: null };
        const changed = !currentBank || JSON.stringify(currentBank) !== JSON.stringify(empty);
        currentBank = empty;
        pendingSelection = '';
        blockedForm = null;
        lastFormSnapshot = null;
        if (changed) {
          try { onBankChange({ ...empty }); } catch (_) { /* The host page remains independent. */ }
        }
        return { ...empty };
      }
      const state = bankDOM();
      const identity = JSON.stringify([state.taskId, flat(state.bankName)]);
      const oldIdentity = currentBank && JSON.stringify([currentBank.taskId, flat(currentBank.bankName)]);
      const snapshot = formSnapshot();
      const stillPreviousForm = snapshot && lastFormSnapshot && snapshot.element === lastFormSnapshot.element && snapshot.text === lastFormSnapshot.text;
      // During a SPA transition the sidebar changes before the old question is
      // replaced. Keep that old form out of the new bank even if titles update first.
      if (currentBank && identity !== oldIdentity && flat(currentBank.bankName) !== flat(state.bankName)) {
        blockedForm = stillPreviousForm ? snapshot : null;
        lastDOMSignature = '';
      } else if (currentBank && identity !== oldIdentity && currentBank.taskId && state.taskId && currentBank.taskId !== state.taskId) {
        if (!(currentBank.loading && !blockedForm)) blockedForm = stillPreviousForm ? snapshot : null;
        lastDOMSignature = '';
      }
      if (blockedForm && (!snapshot || blockedForm.element !== snapshot.element || blockedForm.text !== snapshot.text)) blockedForm = null;
      let bankId = '';
      const taskBank = state.taskId && banksByTask.get(state.taskId);
      if (taskBank && flat(taskBank.bankName) === flat(state.bankName)) bankId = taskBank.bankId;
      if (!bankId && !state.taskId) {
        const named = [...banksById.values()].filter(bank => flat(bank.bankName) === flat(state.bankName));
        if (named.length === 1) bankId = named[0].bankId;
      }
      const loading = state.mismatch || Boolean(blockedForm);
      const displayed = loading ? null : displayedQuestionCount();
      const remembered = bankId && banksById.get(bankId)?.questionCount;
      const questionCount = displayed !== null ? displayed : Number.isSafeInteger(remembered) ? remembered : null;
      const next = { bankId, bankName: state.bankName, taskId: state.taskId, loading, questionCount };
      const changed = !currentBank || JSON.stringify(next) !== JSON.stringify(currentBank);
      currentBank = next;
      lastFormSnapshot = snapshot;
      if (changed) {
        try { onBankChange({ ...next }); } catch (_) { /* Consumers must not affect site navigation. */ }
      }
      flushDeferredSnapshots(next);
      return { ...next };
    }

    function getCurrentBank() { return syncBank(); }

    function ensureBankListeners() {
      if (bankListeners || !isSupportedPage()) return;
      bankListeners = true;
      win.addEventListener?.('hashchange', syncBank);
      win.addEventListener?.('popstate', syncBank);
      win.addEventListener?.('click', event => {
        const item = event.target?.closest?.('.task-content, .task-content-active');
        const name = text(item?.querySelector('.group-title')?.textContent);
        if (name && flat(name) !== flat(currentBank?.bankName)) { pendingSelection = name; syncBank(); }
      }, true);
    }

    function requestContext(context) {
      const current = syncBank();
      const saved = context.bankId && banksById.get(context.bankId);
      const sameTask = saved && saved.taskId && saved.taskId === current.taskId;
      const useCurrent = !saved || sameTask || (!context.answerResponse && !current.loading);
      context.bankName = useCurrent ? current.bankName : saved.bankName;
      context.taskId = useCurrent ? current.taskId : saved.taskId;
      context.requestSequence = ++requestSequence;
      return context;
    }

    function rememberBanks(context, records) {
      const distinct = new Map();
      for (const record of records) if (record.bankId) distinct.set(record.bankId, record);
      for (const record of distinct.values()) {
        const previous = banksById.get(record.bankId);
        if (!context.answerResponse && previous?.requestSequence > context.requestSequence) continue;
        const name = record.bankName || context.bankName;
        const taskId = flat(name) === flat(context.bankName) ? context.taskId || '' : '';
        const value = { bankId: record.bankId, bankName: name, taskId,
          questionCount: Number.isSafeInteger(context.questionCount) ? context.questionCount : previous?.questionCount ?? null,
          requestSequence: Math.max(previous?.requestSequence || 0, context.requestSequence || 0) };
        banksById.set(record.bankId, value);
        if (value.taskId && distinct.size === 1) banksByTask.set(value.taskId, value);
      }
    }

    function emissionContext(context, current, stale = false) {
      const samePage = !current.loading && context.bankId && context.bankId === current.bankId &&
        (!context.taskId || context.taskId === current.taskId) && flat(context.bankName) === flat(current.bankName) && !stale;
      return { ...context, currentBankId: samePage ? current.bankId : '',
        pageQuestionCount: samePage ? displayedQuestionCount() : null };
    }

    function deliver(records, context) {
      try { onQuestions(records, context); } catch (error) { status(`保存题目失败：${error.message || error}`); }
    }

    function flushDeferredSnapshots(current) {
      if (!active || !current.bankId || current.loading) return;
      const pending = deferredSnapshots.get(current.bankId);
      if (!pending) return;
      if ((knownSnapshotOrder.get(current.bankId) || 0) > (pending.context.requestSequence || 0)) {
        deferredSnapshots.delete(current.bankId);
        return;
      }
      const context = emissionContext(pending.context, current);
      if (context.pageQuestionCount === null) return;
      deferredSnapshots.delete(current.bankId);
      deliver(pending.records, context);
    }

    function emit(records, context = {}) {
      if (!records.length) return;
      if (!context.fullSnapshot && records.some(record => deferredSnapshots.has(record.bankId))) return;
      const staleBanks = new Set();
      if (context.fullSnapshot) {
        for (const bankId of new Set(records.map(record => record.bankId))) {
          if ((knownSnapshotOrder.get(bankId) || 0) > (context.requestSequence || 0)) { staleBanks.add(bankId); continue; }
          for (const [key, old] of known) if (old.bankId === bankId) known.delete(key);
          knownSnapshotOrder.set(bankId, context.requestSequence || 0);
        }
      }
      for (const q of records) {
        if (q.questionId && !staleBanks.has(q.bankId)) known.set(`${q.bankId}\u001f${q.questionId}`, q);
      }
      knownContentIndex = null;
      const current = syncBank();
      const metadata = emissionContext(context, current, staleBanks.has(context.bankId));
      const containsImages = records.some(record => /\[图片:https?:\/\//.test(record.stem) || record.options.some(option => /\[图片:https?:\/\//.test(option.text)));
      if (context.fullSnapshot && context.bankId && !staleBanks.has(context.bankId) && containsImages && metadata.pageQuestionCount === null) {
        deferredSnapshots.set(context.bankId, { records, context });
        return;
      }
      deliver(records, metadata);
    }

    function visible(node) {
      if (!node || node.closest?.('#huayi-qb-root')) return false;
      for (let at = node; at && at.nodeType === 1; at = at.parentElement) {
        if (at.hidden || at.getAttribute('aria-hidden') === 'true' || at.style?.display === 'none') return false;
      }
      return true;
    }

    function matchingKnown(question) {
      if (!knownContentIndex) {
        knownContentIndex = new Map();
        for (const record of known.values()) {
          const content = signature(record);
          const keys = [`id:${record.bankId}\u001d${content}`, `name:${flat(record.bankName)}\u001d${content}`];
          for (const key of keys) {
            if (!knownContentIndex.has(key)) knownContentIndex.set(key, []);
            knownContentIndex.get(key).push(record);
          }
        }
      }
      const key = question.bankId ? `id:${question.bankId}` : `name:${flat(question.bankName)}`;
      return knownContentIndex.get(`${key}\u001d${signature(question)}`) || [];
    }

    function getCurrentQuestion() {
      if (!isSupportedPage()) return null;
      const bank = syncBank();
      if (bankDOM().mismatch) return null;
      const forms = [...doc.querySelectorAll(`${ROOT_SELECTOR} .yxtulcdsdk-form`)].filter(visible);
      if (forms.length !== 1) return null;
      const form = forms[0];
      const content = form.querySelector('.yxtulcdsdk-form__content');
      const stemNode = content && [...content.children].find(n => n.matches('[data-rich-text]'));
      const stem = stemNode && text(stemNode);
      if (!stem) return null;
      const labels = [...form.querySelectorAll('.yxtulcdsdk-ques-radio, .yxtulcdsdk-ques-checkbox')];
      if (labels.length < 2) return null;
      const options = labels.map((label, index) => {
        const input = label.querySelector('input');
        const labelNode = label.querySelector('.yxtf-radio__label, .yxtf-checkbox__label');
        const rich = labelNode && labelNode.querySelector('[data-rich-text]');
        const full = text(labelNode || label);
        return { id: input ? idString(input.value) : '', text: rich ? text(rich) : full.replace(/^[A-Z][.、．]\s*/, ''), label: labelFor(index) };
      });
      if (options.some(option => !option.text)) return null;
      let type = form.querySelector('input[type=checkbox], [role=checkbox]') ? 'multiple' : 'single';
      if (options.length === 2 && options.some(o => o.text === '正确') && options.some(o => o.text === '错误')) {
        type = 'judge';
        options.forEach(o => { o.label = o.text; });
      }
      const q = {
        bankId: bank.bankId, bankName: bank.bankName, questionId: '', type, stem, options,
        correctOptionIds: [], answerTexts: [], answerStatus: 'missing', explanation: '',
        source: { kind: 'dom', url: locationURL().split('?')[0].split('#')[0], observedAt: new Date().toISOString() }
      };
      const number = text(form.querySelector('.yxtulcdsdk-form__sub')?.textContent).match(/^\s*(\d+)/);
      const questionIndex = number && Number(number[1]) >= 1 && Number(number[1]) <= 100000 ? Number(number[1]) - 1 : null;
      if (questionIndex !== null) q.questionIndex = questionIndex;
      let matches = matchingKnown(q);
      if (questionIndex !== null) {
        const indexed = matches.filter(item => item.questionIndex === questionIndex);
        if (indexed.length) matches = indexed;
        else if (matches.length && matches.every(item => Number.isSafeInteger(item.questionIndex))) return null;
      }
      if (blockedForm && (!bank.bankId || matches.length !== 1)) return null;
      if (matches.length === 1) {
        // Vue may update the question text before the old radio values. Those
        // transitional controls must not be attached to the new server identity.
        const expectedOptions = matches[0].options;
        if (expectedOptions.every(option => option.id) && options.some(option => option.id &&
          !expectedOptions.some(expected => expected.id === option.id && flat(expected.text) === flat(option.text)))) return null;
        q.questionId = matches[0].questionId;
        q.bankId = matches[0].bankId;
        if (Number.isSafeInteger(matches[0].questionIndex)) q.questionIndex = matches[0].questionIndex;
        if (Number.isSafeInteger(matches[0].contentOccurrence)) q.contentOccurrence = matches[0].contentOccurrence;
        if (matches[0].source?.batchId) q.source.batchId = matches[0].source.batchId;
        if (blockedForm) { blockedForm = null; syncBank(); }
      }
      // A letter-only result row can survive the previous question during a
      // render. Its heading alone does not prove it belongs to this question.
      const main = form.closest(ROOT_SELECTOR);
      const rows = [...main.querySelectorAll('.yxtulcdsdk-examing__result-line')].filter(visible);
      for (const row of rows) {
        const heading = text(row.querySelector('.yxtulcdsdk-examing__result-line-left')?.textContent);
        const answer = text(row.querySelector('.yxtulcdsdk-examing__result-line-right'));
        if (heading === '正确答案' || heading === '标准答案') {
          let selected = [];
          if (type === 'judge') selected = options.filter(o => o.text === answer);
          else if (/^[A-Z](?:[、,，\s]*[A-Z])*$/.test(answer)) {
            const requested = [...new Set(answer.match(/[A-Z]/g))];
            selected = requested.map(letter => options.find(o => o.label === letter)).filter(Boolean);
            if (selected.length !== requested.length) selected = [];
          }
          if (selected.length && (type !== 'single' || selected.length === 1)) {
            const feedbackId = ['data-question-id', 'data-ques-id', 'question-id', 'ques-id']
              .map(name => idString(row.getAttribute?.(name))).find(Boolean);
            const knownAnswer = matches.length === 1 && matches[0].answerStatus === 'confirmed' &&
              ['submitted-list', 'answer-response', 'bound-dom', 'explicit-standard'].includes(matches[0].answerEvidence) ? matches[0] : null;
            const agreesWithKnown = knownAnswer && knownAnswer.answerTexts.length === selected.length &&
              selected.every(option => knownAnswer.answerTexts.some(answerText => flat(answerText) === flat(option.text)));
            const boundToCurrent = q.questionId && feedbackId && feedbackId === q.questionId;
            if ((feedbackId && feedbackId !== q.questionId) || (!boundToCurrent && !agreesWithKnown)) continue;
            q.correctOptionIds = selected.map(o => o.id).filter(Boolean);
            q.answerTexts = selected.map(o => o.text);
            q.answerStatus = 'confirmed';
            q.answerEvidence = boundToCurrent ? 'bound-dom' : knownAnswer.answerEvidence;
          }
        } else if (heading === '解析' || heading === '试题解析' || heading === '答案解析') {
          const feedbackId = ['data-question-id', 'data-ques-id', 'question-id', 'ques-id']
            .map(name => idString(row.getAttribute?.(name))).find(Boolean);
          if (q.answerStatus === 'confirmed' && (!feedbackId || feedbackId === q.questionId)) q.explanation = answer;
        }
      }
      return q;
    }

    function captureCurrent() {
      if (!isSupportedPage()) {
        status('当前为通用网页，可使用本地题库搜索；本站采集未开启。');
        return null;
      }
      const current = getCurrentQuestion();
      if (current) emit([current]);
      else status('当前页面未发现可采集的练习题，请进入题目页面。');
      return current;
    }

    function observePayload(payload, context) {
      if (!active) return;
      // A full list can replace the meaning of even an unchanged question ID.
      // An older answer receipt has no independent stem/options to bind it to
      // that new version; never fill it from the newer cached question.
      if (context.answerResponse && (knownSnapshotOrder.get(context.bankId) || 0) > (context.requestSequence || 0)) return;
      try {
        const observedAt = new Date().toISOString();
        const batchId = `${observedAt}:${++batchSequence}`;
        const snapshotContext = { ...context, observedAt, batchId,
          questionCount: context.answerResponse ? null : responseQuestionCount(payload) };
        const records = extractQuestions(payload, { ...snapshotContext, knownQuestions: known });
        snapshotContext.fullSnapshot = !context.answerResponse && records.some(record => Number.isSafeInteger(record.questionIndex));
        rememberBanks(snapshotContext, records);
        emit(records, snapshotContext);
        syncBank();
        if (records.length) {
          const names = [...new Set(records.map(record => record.bankName).filter(Boolean))];
          const sourceName = names.length === 1 ? names[0] : context.bankName || '来源题库';
          status(`已读取「${sourceName}」${records.length} 道题，标准答案 ${records.filter(q => q.answerStatus === 'confirmed').length} 道。`);
        }
      } catch (_) { status('本次响应结构暂未识别，题目仍可从页面采集。'); }
    }

    function installNetwork() {
      if (!observeNetwork || !isSupportedPage()) return;
      const generation = ++networkGeneration;
      if (typeof win.fetch === 'function') {
        const originalFetch = win.fetch;
        fetchOriginal = originalFetch;
        fetchWrapped = function (...args) {
          const request = args[0];
          const requestURL = typeof request === 'string' || (request && typeof request.href === 'string') ? String(request) : request && request.url;
          const context = classifyURL(requestURL, locationURL());
          if (context) {
            requestContext(context);
            context.questionId = requestQuestionId(args[1] && args[1].body);
          }
          const promise = originalFetch.apply(this, args);
          if (context) Promise.resolve(promise).then(response => {
            if (!active || generation !== networkGeneration || !response.ok) return;
            const contentType = response.headers.get('content-type') || '';
            const length = Number(response.headers.get('content-length') || 0);
            if (!/\bjson\b/i.test(contentType) || length > MAX_RESPONSE) return;
            response.clone().text().then(body => {
              if (active && generation === networkGeneration && body.length <= MAX_RESPONSE) observePayload(JSON.parse(body), context);
            }).catch(() => {});
          }).catch(() => {});
          return promise;
        };
        win.fetch = fetchWrapped;
      }
      const proto = win.XMLHttpRequest && win.XMLHttpRequest.prototype;
      if (!proto) return;
      const originalOpen = proto.open;
      const originalSend = proto.send;
      xhrOpenOriginal = originalOpen;
      xhrSendOriginal = originalSend;
      xhrOpenWrapped = function (method, url, ...args) {
        const result = originalOpen.call(this, method, url, ...args);
        const context = classifyURL(url, locationURL());
        if (context) requestContext(context);
        xhrContext.set(this, context);
        return result;
      };
      xhrSendWrapped = function (body) {
        const context = xhrContext.get(this);
        if (active && generation === networkGeneration && context) {
          context.questionId = requestQuestionId(body);
          const xhr = this;
          const listener = () => {
            pendingXHR.delete(entry);
            if (!active || generation !== networkGeneration || xhr.status < 200 || xhr.status >= 300) return;
            try {
              const type = xhr.getResponseHeader('content-type') || '';
              const length = Number(xhr.getResponseHeader('content-length') || 0);
              if (!/\bjson\b/i.test(type) || length > MAX_RESPONSE) return;
              if (xhr.responseType === 'json') observePayload(xhr.response, context);
              else if (!xhr.responseType || xhr.responseType === 'text') {
                const bodyText = xhr.responseText;
                if (bodyText.length <= MAX_RESPONSE) observePayload(JSON.parse(bodyText), context);
              }
            } catch (_) { /* Unsupported payloads never interfere with the site's requests. */ }
          };
          const entry = { xhr, listener };
          pendingXHR.add(entry);
          xhr.addEventListener('load', listener, { once: true });
        }
        return originalSend.call(this, body);
      };
      proto.open = xhrOpenWrapped;
      proto.send = xhrSendWrapped;
    }

    function uninstallNetwork() {
      networkGeneration++;
      if (fetchWrapped && win.fetch === fetchWrapped) win.fetch = fetchOriginal;
      const proto = win.XMLHttpRequest && win.XMLHttpRequest.prototype;
      if (proto && proto.open === xhrOpenWrapped) proto.open = xhrOpenOriginal;
      if (proto && proto.send === xhrSendWrapped) proto.send = xhrSendOriginal;
      for (const { xhr, listener } of pendingXHR) xhr.removeEventListener('load', listener);
      pendingXHR.clear();
    }

    function copyEvent(event) {
      const target = event.target && (event.target.nodeType === 1 ? event.target : event.target.parentElement);
      if (!copyEnabled || !target?.closest(ROOT_SELECTOR) || target.closest('#huayi-qb-root')) return;
      // Preserve the browser default copy/selection action, suppress only downstream blockers.
      event.stopImmediatePropagation();
    }

    function ensureCopyStyle() {
      if (!copyEnabled || copyStyle?.isConnected || !isSupportedPage()) return;
      const parent = doc.head || doc.documentElement;
      if (!parent) return;
      copyStyle = doc.createElement('style');
      copyStyle.id = 'huayi-qb-copy-style';
      copyStyle.textContent = `${ROOT_SELECTOR},${ROOT_SELECTOR} *{-webkit-user-select:text!important;user-select:text!important}`;
      parent.appendChild(copyStyle);
    }

    function ensureObserver() {
      if (observer || !win.MutationObserver || !isSupportedPage()) return;
      const contextSelectors = '.task-content, .task-content-active, header.o2oPlayFrame-right, .yxtulcdsdk-exam-header, .yxtulcdsdk-answer-card__top, .yxtulcdsdk-uexam-preview-content__base-row-flex--practice, title';
      const questionSelectors = '.yxtulcdsdk-form__content, .yxtulcdsdk-form__sub, .yxtulcdsdk-examing__result-line';
      const insertedSelectors = `${ROOT_SELECTOR}, .yxtulcdsdk-form, .yxtulcdsdk-exam-container, ${contextSelectors}, ${questionSelectors}`;
      function relevantMutation(mutation) {
        const node = mutation.target.nodeType === 1 ? mutation.target : mutation.target.parentElement;
        if (!node || node.closest?.('#huayi-qb-root') || node.id === 'huayi-qb-copy-style') return false;
        const inQuestion = node.closest?.(ROOT_SELECTOR);
        if (inQuestion) {
          if (mutation.type === 'attributes') {
            // checked/disabled/selected and feedback classes change on every
            // answer. They do not change the question or its standard answer.
            if (node.closest?.('.yxtulcdsdk-ques-radio, .yxtulcdsdk-ques-checkbox')) return false;
            return Boolean(node.matches?.(`${ROOT_SELECTOR}, .yxtulcdsdk-form`) ||
              node.closest?.('.yxtulcdsdk-examing__result-line'));
          }
          if (node.closest?.(questionSelectors)) return true;
        }
        if (node.closest?.(contextSelectors)) return true;
        if (mutation.type === 'attributes' && mutation.attributeName === 'task-id' && node.matches?.('.yxtulcdsdk-exam-container')) return true;
        if (mutation.type !== 'childList') return false;
        // Structural additions/removals can introduce an exercise root, but
        // unrelated timers, chat widgets, answer-card cells and our UI cannot.
        return [...(mutation.addedNodes || []), ...(mutation.removedNodes || [])].some(changed => changed.nodeType === 1 &&
          changed.id !== 'huayi-qb-root' && changed.id !== 'huayi-qb-copy-style' &&
          (changed.matches?.(insertedSelectors) || changed.querySelector?.(insertedSelectors)));
      }
      observer = new win.MutationObserver(mutations => {
        if (!mutations.some(relevantMutation) || timer !== null) return;
        timer = win.setTimeout(() => {
          timer = null;
          syncBank();
          if (copyEnabled) ensureCopyStyle();
          if (!active) return;
          const q = getCurrentQuestion();
          if (!q) return;
          const next = JSON.stringify([q.bankId, q.questionId, signature(q), q.correctOptionIds, q.answerTexts, q.explanation]);
          if (next !== lastDOMSignature) { lastDOMSignature = next; emit([q]); }
        }, 120);
      });
      observer.observe(doc, { childList: true, subtree: true, characterData: true, attributes: true, attributeFilter: ['class', 'style', 'hidden', 'task-id', 'data-task-id'] });
    }

    function setCopyEnabled(value) {
      const supported = isSupportedPage();
      if (!supported && !copyEnabled && !copyStyle) return;
      copyEnabled = Boolean(value) && supported;
      for (const type of ['copy', 'cut', 'contextmenu', 'selectstart']) {
        win.removeEventListener?.(type, copyEvent, true);
        if (copyEnabled) win.addEventListener?.(type, copyEvent, true);
      }
      if (copyEnabled) { ensureCopyStyle(); ensureObserver(); }
      else if (copyStyle) { copyStyle.remove(); copyStyle = null; }
      ensureBankListeners();
      ensureObserver();
      syncBank();
    }

    function start() {
      if (active) return;
      active = true;
      if (!isSupportedPage()) {
        syncBank();
        status('当前为通用网页，可使用本地题库搜索；本站采集未开启。');
        return;
      }
      ensureBankListeners();
      ensureObserver();
      installNetwork();
      captureCurrent();
      status('采集已开启；切换练习或正常作答时，自动保存收到的题目与标准答案。');
    }

    function stop() {
      active = false;
      deferredSnapshots.clear();
      win.clearTimeout(timer);
      timer = null;
      uninstallNetwork();
      status('采集已暂停，已保存题库和选择复制功能仍可使用。');
    }

    function clearCache() {
      stop();
      known.clear(); knownContentIndex = null;
      banksById.clear(); banksByTask.clear(); knownSnapshotOrder.clear();
      currentBank = null; pendingSelection = ''; blockedForm = null; lastFormSnapshot = null;
      lastDOMSignature = '';
    }

    return { start, stop, clearCache, captureCurrent, getCurrentQuestion, getCurrentBank, setCopyEnabled, isSupportedPage };
  }

  return { create, extractQuestions, richText };
})();
if (typeof module !== 'undefined' && module.exports) module.exports = QBAdapter;


// ---- src/autofill.js ----
/* Select confirmed local answers. This module never submits forms or changes pages. */
const QBAuto = (() => {
  'use strict';
  const tidy = value => String(value == null ? '' : value).replace(/\u00a0/g, ' ').trim();
  const flat = value => tidy(value).replace(/\s+/gu, '');
  const stemKey = value => flat(tidy(value).replace(/^(?:第\s*\d+\s*题[\s、.．:：]*|\d+\s*[、．]\s*|\d+\.\s+)/u, ''));
  const judgeText = value => /^(正确|对|是|√|true)$/i.test(tidy(value)) ? '正确' : /^(错误|错|否|×|false)$/i.test(tidy(value)) ? '错误' : tidy(value);
  const optionKey = (value, type) => flat(type === 'judge' ? judgeText(value) : value);
  const sorted = values => [...values].sort();
  const optionSet = question => JSON.stringify(sorted(question.options.map(option => optionKey(option.text, question.type))));
  const localCore = supplied => supplied || (typeof QBCore !== 'undefined' ? QBCore : typeof require === 'function' ? require('./core.js') : null);
  const richText = value => {
    const adapter = typeof QBAdapter !== 'undefined' ? QBAdapter : typeof require === 'function' ? require('./adapter.js') : null;
    return adapter ? adapter.richText(value) : tidy(value && typeof value === 'object' ? value.textContent : value);
  };
  const recordIndexes = new WeakMap();
  function candidateRecords(records, question, core) {
    let index = recordIndexes.get(records);
    if (!index || index.core !== core) {
      index = { core, entries: [], byQuestion: new Map(), normalized: new WeakMap() };
      recordIndexes.set(records, index);
    }
    let changed = index.entries.length !== records.length;
    const entries = records.map((record, position) => {
      const rawStem = record && typeof record.stem === 'string' ? record.stem : '';
      const type = record && typeof record.type === 'string' ? record.type : '';
      const old = index.entries[position];
      if (old?.record === record && old.rawStem === rawStem && old.type === type) return old;
      changed = true;
      return { record, rawStem, type, key: rawStem ? JSON.stringify([type, stemKey(rawStem)]) : '' };
    });
    if (changed) {
      index.entries = entries;
      index.byQuestion = new Map();
      for (const entry of entries) {
        if (!entry.key || !entry.record || typeof entry.record !== 'object') continue;
        if (!index.byQuestion.has(entry.key)) index.byQuestion.set(entry.key, []);
        index.byQuestion.get(entry.key).push(entry.record);
      }
    }
    const matches = index.byQuestion.get(JSON.stringify([question.type, stemKey(question.stem)])) || [];
    return matches.map(input => {
      // Only exact-stem candidates need full answer validation. This signature
      // also detects in-place edits to answers/options, not just array replacement.
      let signature;
      try {
        signature = JSON.stringify([input.bankId, input.bankName, input.questionId, input.type, input.stem,
          input.options, input.correctOptionIds, input.answerTexts, input.answerStatus, input.conflicts,
          input.questionIndex, input.contentOccurrence, input.questionIdAliases]);
      } catch (_) { return null; }
      const saved = index.normalized.get(input);
      if (saved && saved.signature === signature) return saved.record;
      try {
        const record = core.normalizeRecord(input);
        index.normalized.set(input, { signature, record });
        return record;
      } catch (_) { return null; }
    }).filter(Boolean);
  }

  function planAnswer(records, current, suppliedCore) {
    const result = (status, message, more = {}) => ({ status, message, labels: [], answerTexts: [], ...more });
    const core = localCore(suppliedCore);
    if (!core || !current || !Array.isArray(records)) return result('unsupported', '当前网页未识别到可自动选择的题目。');
    let question;
    try { question = core.normalizeRecord({ ...current, answerStatus: 'missing' }); }
    catch (_) { return result('unsupported', '当前题目结构不完整，已跳过。'); }
    if (!['single', 'multiple', 'judge'].includes(question.type) || question.options.length < 2 || question.options.length > 100) return result('unsupported', '当前题型暂不支持自动选择。');
    // Repeated text requires mapAnswers to prove the complete option identity or correct set.
    if (new Set(question.options.map(option => option.label)).size !== question.options.length) return result('ambiguous', '当前选项标记重复，无法唯一对应，已跳过。');
    const relevant = [];
    for (const record of candidateRecords(records, question, core)) {
      if (record.type !== question.type || stemKey(record.stem) !== stemKey(question.stem) || optionSet(record) !== optionSet(question)) continue;
      if (question.bankId && record.bankId && question.bankId !== record.bankId) continue;
      if (!record.bankId && question.bankName && question.bankName !== '未命名题库' && record.bankName !== '未命名题库' && flat(record.bankName) !== flat(question.bankName)) continue;
      relevant.push(record);
    }
    let candidates = relevant;
    if (question.bankId) {
      const exactBank = relevant.filter(record => record.bankId === question.bankId);
      if (exactBank.length) candidates = relevant.filter(record => record.bankId === question.bankId || !record.bankId);
    } else if (question.bankName && question.bankName !== '未命名题库') {
      const sameName = relevant.filter(record => flat(record.bankName) === flat(question.bankName));
      if (sameName.length) candidates = sameName;
    }
    if (candidates.some(record => record.answerStatus === 'conflict')) return result('ambiguous', '本地题库存在该题的冲突答案，已跳过。');
    const confirmed = candidates.filter(record => record.answerStatus === 'confirmed');
    if (!confirmed.length) return result('missing', '未找到题干、题型和全部选项一致的已确认答案。');
    const signatures = new Set(confirmed.map(record => JSON.stringify(sorted(record.answerTexts.map(value => optionKey(value, record.type))))));
    if (signatures.size !== 1) return result('ambiguous', '相同题目对应多个不同标准答案，已跳过。');
    const mapped = confirmed.map(record => ({ record, mapping: core.mapAnswers(record, question) }));
    if (mapped.some(item => item.mapping.status !== 'matched' || !item.mapping.labels.length)) return result('ambiguous', '标准答案无法安全对应当前选项，已跳过。');
    const labelSets = new Set(mapped.map(item => JSON.stringify(sorted(item.mapping.labels))));
    if (labelSets.size !== 1) return result('ambiguous', '标准答案对应的选项位置不一致，已跳过。');
    return result('ready', '已找到唯一对应的标准答案。', { labels: [...mapped[0].mapping.labels], answerTexts: [...mapped[0].mapping.answerTexts], record: mapped[0].record });
  }

  function create({ window: win, document: doc, core: suppliedCore, getRecords = () => [], getQuestion = () => null, getBank = () => null, onStatus = () => {}, onChange = () => {} }) {
    const core = localCore(suppliedCore);
    const SITE_FORM = '.yxtulcdsdk-pc-marking-main .yxtulcdsdk-form';
    const GENERIC = 'fieldset, .question, .question-item, [data-question]';
    let state = { enabled: false, busy: false, status: 'idle', message: '自动答题未开启。', answeredCount: 0, skippedCount: 0, lastStem: '' };
    let observer = null, timer = null, interval = null, generation = 0, destroyed = false;
    let attempts = new WeakMap();
    const setTimer = (fn, delay) => win.setTimeout(fn, delay);
    function emit(patch) {
      const before = state;
      state = { ...state, ...patch };
      if (JSON.stringify(before) === JSON.stringify(state)) return;
      try { onChange({ ...state }); } catch (_) { /* UI failures must not affect a page. */ }
      if (before.message !== state.message) try { onStatus(state.message); } catch (_) { /* Ignore callback errors. */ }
    }
    function visible(element) {
      if (!element || !element.isConnected || element.closest('#huayi-qb-root')) return false;
      for (let at = element; at && at.nodeType === 1; at = at.parentElement) {
        if (at.hidden || at.getAttribute('aria-hidden') === 'true') return false;
        const style = win.getComputedStyle?.(at);
        if (style?.display === 'none' || style?.visibility === 'hidden' || style?.visibility === 'collapse') return false;
      }
      return true;
    }
    function labelText(input, container) {
      let label = input.labels && [...input.labels].find(item => container.contains(item));
      if (!label) label = input.closest('label');
      if (label) {
        const rich = label.querySelector('.yxtf-radio__label [data-rich-text], .yxtf-checkbox__label [data-rich-text]');
        if (rich) return richText(rich);
        const clone = (label.querySelector('.yxtf-radio__label, .yxtf-checkbox__label') || label).cloneNode(true);
        clone.querySelectorAll('input,button,script,style').forEach(node => node.remove());
        return richText(clone).replace(/^(?:[A-Z][.、．):：]|\[[A-Z]\])\s*/u, '');
      }
      const labelled = tidy(input.getAttribute('aria-labelledby')).split(/\s+/u).filter(Boolean).map(id => doc.getElementById(id)).filter(node => node && container.contains(node));
      return tidy(labelled.length ? labelled.map(node => richText(node)).join(' ') : input.getAttribute('aria-label'));
    }
    function controls(container, site) {
      const selector = site ? '.yxtulcdsdk-ques-radio input[type="radio"],.yxtulcdsdk-ques-checkbox input[type="checkbox"]' : 'input[type="radio"],input[type="checkbox"]';
      const inputs = [...container.querySelectorAll(selector)].filter(input => site || input.closest(GENERIC) === container);
      if (inputs.length < 2 || inputs.length > 100) return null;
      const types = new Set(inputs.map(input => input.type));
      if (types.size !== 1 || inputs.some(input => input.disabled || input.matches(':disabled') || input.closest('[aria-disabled="true"]'))) return null;
      if (inputs.some(input => !visible(input) && !visible(input.closest('label')))) return null;
      if (!site && inputs[0].type === 'radio' && new Set(inputs.map(input => input.name)).size > 1) return null;
      const texts = inputs.map(input => labelText(input, container));
      if (texts.some(value => !value)) return null;
      return { inputs, texts, type: inputs[0].type === 'checkbox' ? 'multiple' : 'single' };
    }
    function readSite(container) {
      if (!visible(container)) return null;
      const current = getQuestion();
      const bank = getBank();
      if (!current || bank?.loading) return null;
      const set = controls(container, true);
      if (!set || set.inputs.length !== current.options?.length || set.texts.some((value, index) => optionKey(value, current.type) !== optionKey(current.options[index].text, current.type))) return null;
      return { container, inputs: set.inputs, question: current, site: true, bankIdentity: JSON.stringify([bank?.taskId || '', bank?.bankId || '']) };
    }
    function readGeneric(container) {
      if (!visible(container)) return null;
      const set = controls(container, false);
      if (!set) return null;
      const titles = [...container.querySelectorAll(':scope > legend, :scope > .question-title, :scope > [data-question-title], :scope > .question-stem, :scope > .stem, :scope > h2, :scope > h3, :scope > p')].filter(node => visible(node) && !node.querySelector('input'));
      if (titles.length !== 1) return null;
      const stem = richText(titles[0]);
      if (!stem || stem.length > 100000) return null;
      const judged = set.type === 'single' && set.texts.length === 2 && set.texts.map(judgeText).includes('正确') && set.texts.map(judgeText).includes('错误');
      const type = judged ? 'judge' : set.type;
      const question = {
        bankId: tidy(container.getAttribute('data-bank-id')), bankName: tidy(container.getAttribute('data-bank-name')),
        questionId: tidy(container.getAttribute('data-question-id') || container.getAttribute('data-ques-id')), stem, type, options: set.inputs.map((input, index) => ({ id: input.value || input.id || '', text: judged ? judgeText(set.texts[index]) : set.texts[index], label: judged ? judgeText(set.texts[index]) : String.fromCharCode(65 + index) })),
        answerStatus: 'missing', answerTexts: [], correctOptionIds: []
      };
      return { container, inputs: set.inputs, question, site: false };
    }
    function allCandidates() {
      const siteForms = [...doc.querySelectorAll(SITE_FORM)].filter(visible);
      if (siteForms.length) return siteForms.length === 1 ? [readSite(siteForms[0])].filter(Boolean) : [];
      return [...doc.querySelectorAll(GENERIC)].map(readGeneric).filter(Boolean);
    }
    function fingerprint(candidate) {
      const question = candidate.question;
      return JSON.stringify([question.bankId || '', question.bankName || '', candidate.bankIdentity || '', question.questionId || '',
        question.questionIndex ?? null, question.contentOccurrence ?? null, question.type, stemKey(question.stem),
        question.options.map(option => [option.id || '', option.label, optionKey(option.text, question.type)]),
        candidate.inputs.map(input => [input.value, input.id, input.name, input.type])]);
    }
    function stillSame(candidate, mark) {
      if (!candidate.container.isConnected || candidate.inputs.some(input => !input.isConnected || input.disabled)) return false;
      const current = candidate.site ? readSite(candidate.container) : readGeneric(candidate.container);
      return current && fingerprint(current) === mark && current.inputs.length === candidate.inputs.length && current.inputs.every((input, index) => input === candidate.inputs[index]);
    }
    function attempted(candidate, plan) { return `${fingerprint(candidate)}\u001f${plan.status}\u001f${JSON.stringify(sorted(plan.answerTexts || []))}`; }
    function desired(candidate, plan) { return candidate.question.options.map(option => plan.labels.includes(option.label)); }
    function alreadyChosen(candidate, flags) { return candidate.inputs.every((input, index) => Boolean(input.checked) === flags[index]); }
    async function settled(candidate, mark, runGeneration, continuous) {
      // A single Promise only waits one microtask. Vue and native event handlers
      // can schedule further microtasks or a later render before changing values.
      // Observe two distinct task turns before selecting any next option.
      for (let check = 0; check < 2; check++) {
        await new Promise(resolve => globalThis.setTimeout(resolve, 50));
        if (destroyed || generation !== runGeneration || (continuous && !state.enabled)) return 'cancelled';
        if (!stillSame(candidate, mark)) return 'changed';
      }
      return 'stable';
    }
    function skipped(message, stem = '', count = true) {
      emit({ busy: false, status: 'skipped', message, lastStem: stem, skippedCount: state.skippedCount + (count ? 1 : 0) });
      return { status: 'skipped', message };
    }
    async function answerCurrent(options = {}) {
      const continuous = options.continuous === true;
      if (destroyed) return { status: 'cancelled', message: '自动答题已关闭。' };
      if (state.busy) return { status: 'busy', message: '正在处理当前题目。' };
      if (continuous && !state.enabled) return { status: 'cancelled', message: '连续自动选择已暂停。' };
      const candidates = allCandidates();
      if (!candidates.length) return continuous ? { status: 'idle', message: '等待可识别的选择题。' } : skipped('当前网页未识别到明确的题干和选项，已跳过。');
      const prioritized = [...candidates].sort((a, b) => Number(Boolean(b.container.matches('.current,.is-active,[aria-current="true"]'))) - Number(Boolean(a.container.matches('.current,.is-active,[aria-current="true"]'))));
      let candidate, plan, attempt;
      for (const item of prioritized) {
        const proposal = planAnswer(getRecords(), item.question, core);
        const key = attempted(item, proposal);
        if (continuous && attempts.get(item.container) === key) continue;
        candidate = item; plan = proposal; attempt = key; break;
      }
      if (!candidate) return { status: 'idle', message: '当前识别的题目已处理。' };
      const questionStem = candidate.question.stem;
      attempts.set(candidate.container, attempt);
      if (plan.status !== 'ready') return skipped(plan.message, questionStem);
      const flags = desired(candidate, plan);
      if (candidate.question.type !== 'multiple' && flags.filter(Boolean).length !== 1) return skipped('单选或判断题的目标选项不唯一，已跳过。', questionStem);
      if (alreadyChosen(candidate, flags)) {
        emit({ status: 'answered', message: '当前题已选择正确选项。', lastStem: questionStem });
        return { status: 'answered', alreadySelected: true, labels: plan.labels, answerTexts: plan.answerTexts };
      }
      const mark = fingerprint(candidate);
      const runGeneration = generation;
      emit({ busy: true, status: 'matched', message: `正在选择：${plan.answerTexts.join('；')}`, lastStem: questionStem });
      try {
        const initial = await settled(candidate, mark, runGeneration, continuous);
        if (initial === 'cancelled') return { status: 'cancelled', message: '自动选择已暂停。' };
        if (initial !== 'stable') return skipped('题目仍在切换或选项身份变化，已停止本次选择。', questionStem);
        const actions = candidate.question.type === 'multiple'
          ? candidate.inputs.map((input, index) => ({ input, index })).filter(({ input, index }) => Boolean(input.checked) !== flags[index])
          : candidate.inputs.map((input, index) => ({ input, index })).filter(({ index }) => flags[index]);
        for (const { input } of actions) {
          if (destroyed || generation !== runGeneration || (continuous && !state.enabled)) {
            emit({ busy: false, status: 'idle', message: '自动选择已暂停。' });
            return { status: 'cancelled', message: '自动选择已暂停。' };
          }
          if (!stillSame(candidate, mark)) return skipped('点击前题目或选项已变化，已停止本次选择。', questionStem);
          input.click();
          const next = await settled(candidate, mark, runGeneration, continuous);
          if (destroyed || generation !== runGeneration || (continuous && !state.enabled)) {
            emit({ busy: false, status: 'idle', message: '自动选择已暂停。' });
            return { status: 'cancelled', message: '自动选择已暂停。' };
          }
          if (next !== 'stable') return skipped('页面在选择过程中换题或替换控件，已停止后续点击。', questionStem);
        }
        if (!alreadyChosen(candidate, flags)) return skipped('网页未保留预期的选中状态，请人工核对。', questionStem);
        emit({ busy: false, status: 'answered', message: `已选择正确选项：${plan.labels.join('、')}`, answeredCount: state.answeredCount + 1, lastStem: questionStem });
        return { status: 'answered', labels: plan.labels, answerTexts: plan.answerTexts };
      } catch (error) {
        return skipped(`自动选择未完成：${error.message || '控件操作失败'}`, questionStem);
      } finally { if (state.busy) emit({ busy: false }); }
    }
    function schedule() {
      if (!state.enabled || destroyed) return;
      win.clearTimeout(timer);
      timer = setTimer(() => { timer = null; void answerCurrent({ continuous: true }); }, 160);
    }
    function stopObservers() {
      win.clearTimeout(timer); win.clearInterval(interval); timer = null; interval = null;
      if (observer) observer.disconnect(); observer = null;
    }
    function setEnabled(value) {
      if (destroyed) return;
      const enabled = Boolean(value);
      if (state.enabled === enabled) {
        // A page can be hidden while a one-shot selection is awaiting a UI
        // microtask. Calling false must cancel that run even without continuous mode.
        if (!enabled) {
          generation++;
          stopObservers();
          if (state.busy) emit({ busy: false, status: 'idle', message: '自动选择已暂停。' });
        }
        return;
      }
      generation++;
      stopObservers();
      emit({ enabled, busy: false, status: 'idle', message: enabled ? '连续自动选择已开启，仅处理明确匹配的题目。' : '连续自动选择已暂停。' });
      if (!enabled) return;
      attempts = new WeakMap();
      if (win.MutationObserver) {
        observer = new win.MutationObserver(mutations => {
          if (mutations.some(mutation => {
            const element = mutation.target.nodeType === 1 ? mutation.target : mutation.target.parentElement;
            return element && !element.closest('#huayi-qb-root');
          })) schedule();
        });
        observer.observe(doc, { subtree: true, childList: true, characterData: true, attributes: true,
          attributeFilter: ['class', 'hidden', 'disabled', 'aria-disabled', 'value', 'data-question-id', 'data-ques-id', 'data-bank-id'] });
      }
      interval = win.setInterval(schedule, 1500);
      schedule();
    }
    function destroy() { setEnabled(false); stopObservers(); destroyed = true; generation++; }
    return { answerCurrent, setEnabled, isEnabled: () => state.enabled, getState: () => ({ ...state }), destroy };
  }
  return { planAnswer, create };
})();
if (typeof module !== 'undefined' && module.exports) module.exports = QBAuto;


// ---- src/collector.js ----
/* Opt-in completion of one Huayi judgment practice, through ordinary DOM clicks. */
const QBCollector = (() => {
  'use strict';
  const MAIN = '.yxtulcdsdk-pc-marking-main';
  const FORM = `${MAIN} .yxtulcdsdk-form[practice]`;
  const EVIDENCE = new Set(['submitted-list', 'answer-response', 'bound-dom', 'explicit-standard']);
  const trim = value => String(value == null ? '' : value).replace(/\u00a0/g, ' ').trim();
  const flat = value => trim(value).replace(/\s+/gu, '');
  const optionsKey = question => JSON.stringify((question.options || []).map(option => [trim(option.id), flat(option.text)]).sort((a, b) => JSON.stringify(a).localeCompare(JSON.stringify(b))));
  const identity = question => JSON.stringify([question.bankId, question.questionId, question.questionIndex, flat(question.stem), optionsKey(question)]);
  const evidence = record => EVIDENCE.has(record.answerEvidence) || (record.answerSource || record.source)?.kind === 'network' &&
    /\/upm\/[^/]+\/users\/[^/]+\/(?:wrong\/)?answer(?:[?#]|$)/u.test((record.answerSource || record.source)?.url || '');

  function create({ window: win, document: doc, core, getRecords = () => [], getQuestion = () => null,
    getBank = () => null, isCollecting = () => false, onChange = () => {} }) {
    let state = { active: false, phase: 'idle', message: '练习补齐未启动。', reason: '', answered: 0, skipped: 0,
      current: 0, total: 0, bankId: '', bankName: '', taskId: '' };
    let destroyed = false, timer = null, generation = 0, binding = null, pending = null, navigation = null;
    let indexSource = null, indexLength = -1, recordIndex = null, idIndex = null;
    const visited = new Map();
    const now = () => win.Date?.now ? win.Date.now() : Date.now();
    const getState = () => ({ ...state });
    function update(patch) {
      const old = state;
      state = { ...state, ...patch };
      if (old.phase !== state.phase || old.active !== state.active) {
        try { onChange(getState()); } catch (_) { /* UI code cannot grant further actions. */ }
      }
    }
    function stop(reason = '已停止练习补齐。') {
      generation++;
      if (timer !== null) win.clearTimeout(timer);
      timer = null; pending = null; navigation = null;
      update({ active: false, phase: 'stopped', reason: trim(reason), message: trim(reason) || '已停止练习补齐。' });
      return getState();
    }
    function visible(node) {
      if (!node || node.isConnected === false || node.closest?.('#huayi-qb-root')) return false;
      for (let current = node; current && current.nodeType === 1; current = current.parentElement) {
        if (current.hidden || current.getAttribute?.('aria-hidden') === 'true') return false;
        const style = win.getComputedStyle?.(current);
        if (style?.display === 'none' || style?.visibility === 'hidden' || style?.visibility === 'collapse') return false;
      }
      return true;
    }
    function context() {
      const url = new URL(String(win.location?.href || ''));
      if (!['www.shhuayi-elearning.cn', 'shhuayi-elearning.cn'].includes(url.hostname) ||
        url.pathname !== '/o2o/' || !/^#\/playinfo(?:\?|$)/u.test(url.hash)) throw new Error('仅支持华谊培训大纲中的判断练习页面。');
      const params = new URLSearchParams(url.hash.includes('?') ? url.hash.slice(url.hash.indexOf('?') + 1) : '');
      if (params.get('wq') === '1' || url.searchParams.get('wq') === '1' || /wrong/iu.test(url.hash)) throw new Error('错题重做不属于本次完整题库补齐范围。');
      if (!isCollecting()) throw new Error('采集已关闭或题库存储不可用，练习补齐已停止。');
      const selected = doc.querySelector('.task-content-active');
      if (selected && (!/练习/u.test(selected.textContent || '') || /考试/u.test(selected.textContent || ''))) throw new Error('当前培训任务不是明确的练习，不能启动。');
      const forms = [...doc.querySelectorAll(FORM)].filter(visible);
      if (forms.length !== 1) throw new Error('当前页面不是唯一的正常练习题，正式考试或不完整页面不能补齐。');
      const form = forms[0], main = form.closest(MAIN);
      if (!main || !visible(main)) throw new Error('练习题目区域尚未完整显示。');
      const heading = trim(main.querySelector('.standard-size-14 span')?.textContent);
      if (heading !== '判断题') throw new Error('本功能只支持判断题练习。');
      const bank = getBank();
      const taskId = trim(bank?.taskId || params.get('taskId'));
      const total = bank?.questionCount;
      if (!bank || bank.loading || !trim(bank.bankId) || !taskId || ![500, 232].includes(total)) throw new Error('当前题库身份或页面总题数未确认，请等待题库加载。');
      const progress = [...doc.querySelectorAll('.yxtulcdsdk-answer-card__top')].filter(visible);
      const counts = progress.map(node => trim(node.textContent).match(/(\d+)\s*\/\s*(\d+)(?!\d)/u)).filter(Boolean);
      if (counts.length !== 1 || Number(counts[0][2]) !== total || Number(counts[0][1]) > total) throw new Error('页面答题卡总数与当前题库不一致，已停止。');
      const route = `${url.pathname}${url.search}${url.hash}`;
      if (binding && (bank.bankId !== binding.bankId || taskId !== binding.taskId || route !== binding.route || total !== binding.total)) {
        throw new Error('题库、任务或地址已变化，练习补齐已停止。');
      }
      return { bank, taskId, total, route, form, main };
    }
    function readView(ctx) {
      const question = getQuestion();
      const number = trim(ctx.form.querySelector('.yxtulcdsdk-form__sub')?.textContent).match(/^(\d+)\s*[.．、]?$/u);
      if (!number || !question || question.type !== 'judge' || question.bankId !== ctx.bank.bankId || !trim(question.questionId) ||
        !Number.isSafeInteger(question.questionIndex) || question.questionIndex !== Number(number[1]) - 1 ||
        question.questionIndex < 0 || question.questionIndex >= ctx.total || question.options?.length !== 2 || !trim(question.stem)) return null;
      const labels = [...ctx.form.querySelectorAll('.yxtulcdsdk-ques-radio')].filter(visible);
      if (labels.length !== 2) return null;
      const controls = labels.map(label => ({ label, input: label.querySelector('input[type="radio"]'),
        text: trim(label.querySelector('.yxtf-radio__label')?.textContent || label.textContent) }));
      if (controls.some(control => !control.input || !control.input.isConnected || !control.input.value) ||
        controls.some((control, position) => control.text !== trim(question.options[position].text) || trim(control.input.value) !== trim(question.options[position].id)) ||
        new Set(controls.map(control => control.text)).size !== 2 || !controls.some(control => control.text === '正确') || !controls.some(control => control.text === '错误')) return null;
      const feedback = [...ctx.main.querySelectorAll('.yxtulcdsdk-examing__result-line')].filter(visible).filter(row =>
        ['正确答案', '标准答案'].includes(trim(row.querySelector('.yxtulcdsdk-examing__result-line-left')?.textContent)));
      if (feedback.length > 1) throw new Error('当前题出现多个标准答案展示，已停止核验。');
      let standard = '';
      if (feedback.length) {
        const row = feedback[0];
        const rowId = ['data-question-id', 'data-ques-id', 'question-id', 'ques-id'].map(name => trim(row.getAttribute(name))).find(Boolean);
        if (rowId && rowId !== question.questionId) throw new Error('页面标准答案仍属于另一道题，已停止。');
        standard = trim(row.querySelector('.yxtulcdsdk-examing__result-line-right')?.textContent);
        if (!['正确', '错误'].includes(standard)) throw new Error('网站标准答案尚不明确，已停止。');
      }
      return { ...ctx, question, controls, standard, feedbackPresent: feedback.length === 1,
        checked: controls.some(control => control.input.checked), mark: identity(question) };
    }
    function recordsAt(index) {
      const records = getRecords();
      if (!Array.isArray(records)) throw new Error('本地题库不可读取，已停止。');
      if (indexSource !== records || indexLength !== records.length) {
        indexSource = records; indexLength = records.length; recordIndex = new Map(); idIndex = new Map();
        for (const record of records) {
          if (!record || record.bankId !== binding.bankId || !Number.isSafeInteger(record.questionIndex)) continue;
          if (!recordIndex.has(record.questionIndex)) recordIndex.set(record.questionIndex, []);
          recordIndex.get(record.questionIndex).push(record);
          for (const id of new Set([record.questionId, ...(record.questionIdAliases || [])].filter(Boolean))) {
            if (!idIndex.has(id)) idIndex.set(id, []);
            idIndex.get(id).push(record);
          }
        }
      }
      return recordIndex.get(index) || [];
    }
    function matchingRecord(question) {
      const candidates = recordsAt(question.questionIndex).filter(record => record.type === 'judge' && flat(record.stem) === flat(question.stem) && optionsKey(record) === optionsKey(question) &&
        [record.questionId, ...(record.questionIdAliases || [])].includes(question.questionId));
      if (candidates.length > 1) throw new Error('同一题目位置存在多个匹配记录，已停止避免重复提交。');
      const record = candidates[0];
      if (!record) {
        throw new Error('当前题不能与本地题库的位置、完整内容及题目ID唯一对应，已停止。');
      }
      if ((idIndex.get(question.questionId) || []).length !== 1) throw new Error('当前题目ID或别名对应多个原题位置，已停止。');
      if (record.answerStatus === 'conflict' || record.conflicts?.length) throw new Error('本地当前题标准答案存在冲突，已停止。');
      if (record.answerStatus === 'missing') return { kind: 'missing', record };
      if (record.answerStatus !== 'confirmed' || !evidence(record)) throw new Error('当前题的已保存答案缺少可核验来源，已停止。');
      const mapped = core.mapAnswers(record, question);
      if (mapped.status !== 'matched' || mapped.answerTexts.length !== 1 || !['正确', '错误'].includes(mapped.answerTexts[0])) throw new Error('标准答案不能唯一对应当前题目，已停止。');
      return { kind: 'confirmed', record, standard: mapped.answerTexts[0] };
    }
    function clickable(element) {
      return visible(element) && typeof element.click === 'function' && !element.disabled && element.getAttribute?.('aria-disabled') !== 'true' &&
        !element.closest?.('[aria-disabled="true"]');
    }
    function assertBeforeClick(view) {
      if (!state.active || destroyed) return false;
      const fresh = readView(context());
      if (!fresh || fresh.mark !== view.mark || fresh.form !== view.form) throw new Error('点击前题目身份发生变化，已停止。');
      return true;
    }
    function schedule() {
      if (!state.active || destroyed || timer !== null) return;
      const token = generation;
      timer = win.setTimeout(() => { timer = null; if (state.active && !destroyed && token === generation) tick(); }, 300);
    }
    function beginNavigation(view, target) {
      let button;
      if (target === 0 && view.question.questionIndex !== 0) {
        const matches = [...doc.querySelectorAll('.yxtulcdsdk-pc-card-list li')].filter(node => visible(node) && trim(node.textContent) === '1');
        if (matches.length !== 1) throw new Error('答题卡第1题入口不唯一，不能安全从头核验。');
        button = matches[0];
      } else {
        const matches = [...view.main.querySelectorAll('.yxtulcdsdk-examing__btns button')].filter(node => visible(node) && trim(node.textContent) === '下一题');
        if (matches.length !== 1) throw new Error('没有唯一的下一题按钮；不会点击结束、提交或交卷。');
        button = matches[0];
      }
      if (!clickable(button)) throw new Error('换题按钮暂不可用，已停止保留当前结果。');
      navigation = { from: view.question.questionIndex, target, deadline: now() + 15000 };
      update({ phase: 'navigating', message: `正在核对第 ${target + 1} 题。` });
      if (!assertBeforeClick(view)) return;
      button.click();
    }
    function finish() {
      if (!state.active) return;
      if (visited.size !== binding.total) throw new Error('本次尚未核对完整题库，不能标记完成。');
      for (let index = 0; index < binding.total; index++) {
        const question = visited.get(index);
        if (!question || matchingRecord(question).kind !== 'confirmed') throw new Error(`第 ${index + 1} 题标准答案尚未完整核验，已停止。`);
      }
      generation++;
      if (timer !== null) win.clearTimeout(timer);
      timer = null; pending = null; navigation = null;
      update({ active: false, phase: 'completed', reason: '', message: `已核验 ${binding.total} 道判断题。本次提交 ${state.answered} 题，跳过 ${state.skipped} 道已有标准答案的题目。` });
    }
    function advance(view, skipped) {
      visited.set(view.question.questionIndex, { ...view.question, options: view.question.options.map(option => ({ ...option })) });
      if (skipped) state = { ...state, skipped: state.skipped + 1 };
      pending = null;
      if (view.question.questionIndex === binding.total - 1) return finish();
      beginNavigation(view, view.question.questionIndex + 1);
    }
    function decide(view) {
      update({ phase: 'checking', current: view.question.questionIndex + 1, message: `正在核验第 ${view.question.questionIndex + 1} / ${binding.total} 题。` });
      if (!state.active) return;
      const local = matchingRecord(view.question);
      if (local.kind === 'confirmed') {
        if (view.feedbackPresent && view.standard !== local.standard) throw new Error('网页反馈与本地标准答案不一致，已停止保留冲突。');
        return advance(view, true);
      }
      pending = { mark: view.mark, questionIndex: view.question.questionIndex, deadline: now() + 15000, clicked: false };
      if (view.feedbackPresent || view.checked) {
        update({ phase: 'waiting-answer', message: '当前题已有选择或反馈，正在等待同题标准答案入库，不会重复提交。' });
        return;
      }
      const target = view.controls.find(control => control.text === '正确');
      if (!target || !clickable(target.label) || target.input.disabled) throw new Error('当前题“正确”选项不可正常操作，已停止。');
      update({ phase: 'selecting', message: `正在通过正常练习提交第 ${view.question.questionIndex + 1} 题，以取得网站标准反馈。` });
      if (!assertBeforeClick(view)) return;
      target.label.click();
      if (!state.active) return;
      pending.clicked = true;
      update({ phase: 'waiting-answer', answered: state.answered + 1, message: '已提交一次，等待网站标准反馈及同题可信记录；不会重复点击。' });
    }
    function tick() {
      try {
        const ctx = context(), view = readView(ctx);
        if (state.phase === 'navigating') {
          if (now() >= navigation.deadline) throw new Error('换题等待超过15秒，已停止。');
          if (!view || view.question.questionIndex === navigation.from) return;
          if (view.question.questionIndex !== navigation.target) throw new Error('页面跳到了其他题目，已停止。');
          navigation = null;
          decide(view);
        } else if (state.phase === 'waiting-answer') {
          if (!view || view.mark !== pending.mark) throw new Error('等待反馈时题目或选项已变化，已停止。');
          if (now() >= pending.deadline) throw new Error('标准反馈或可信入库等待超过15秒，已停止；请人工核对当前题。');
          const local = matchingRecord(view.question);
          if (!view.feedbackPresent || local.kind !== 'confirmed') return;
          if (local.standard !== view.standard) throw new Error('网站标准反馈与本地入库答案不一致，已停止。');
          advance(view, !pending.clicked);
        } else {
          if (!view) throw new Error('当前题目或选项尚不完整，已停止。');
          if (view.question.questionIndex !== 0 && visited.size === 0) beginNavigation(view, 0);
          else decide(view);
        }
      } catch (error) { stop(error.message || '练习补齐遇到异常，已停止。'); }
      finally { schedule(); }
    }
    function start() {
      if (destroyed || state.active) return getState();
      try {
        if (!core?.mapAnswers) throw new Error('题库核验模块不可用。');
        binding = null;
        const ctx = context(), view = readView(ctx);
        if (!view) throw new Error('当前判断练习题目未完整加载，不能启动。');
        binding = { bankId: ctx.bank.bankId, bankName: ctx.bank.bankName, taskId: ctx.taskId, total: ctx.total, route: ctx.route };
        visited.clear(); pending = null; navigation = null; indexSource = null; indexLength = -1; recordIndex = null; idIndex = null;
        generation++;
        update({ active: true, phase: 'checking', reason: '', answered: 0, skipped: 0, current: view.question.questionIndex + 1,
          total: ctx.total, bankId: binding.bankId, bankName: binding.bankName, taskId: binding.taskId,
          message: '练习补齐已手动启动，将从第1题核验本题库；仅使用正常练习控件。' });
        schedule();
      } catch (error) { stop(error.message || '不能启动练习补齐。'); }
      return getState();
    }
    const routeChanged = () => { if (state.active) stop('页面地址已变化，练习补齐已停止。'); };
    win.addEventListener?.('hashchange', routeChanged);
    win.addEventListener?.('popstate', routeChanged);
    win.addEventListener?.('pagehide', routeChanged);
    function destroy() {
      stop('练习补齐已关闭。'); destroyed = true;
      win.removeEventListener?.('hashchange', routeChanged);
      win.removeEventListener?.('popstate', routeChanged);
      win.removeEventListener?.('pagehide', routeChanged);
    }
    return { start, stop, getState, destroy };
  }
  return { create };
})();
if (typeof module !== 'undefined' && module.exports) module.exports = QBCollector;


// ---- src/app.js ----
// UI and persistence stay inside the userscript sandbox. Page data is rendered as text.
(() => {
  const FRAME_SHORTCUT = 'huayi-qb.frame-shortcut.v1';
  const isToggleShortcut = event => event.altKey && event.shiftKey && !event.ctrlKey && !event.metaKey &&
    (event.code === 'KeyQ' || (!event.code && String(event.key).toLowerCase() === 'q')) && !event.repeat;
  // Frames only forward the explicit shortcut. Keep one panel and one set of
  // storage/network handlers in the top page; never relay frame text or answers.
  if (window.top !== window.self) {
    window.addEventListener('keydown', event => {
      if (!isToggleShortcut(event)) return;
      event.preventDefault();
      window.top.postMessage({ type: FRAME_SHORTCUT }, '*');
    }, true);
    return;
  }
  const CONFIG_KEY = 'huayi-qb.config.v1';
  const RECORDS_KEY = 'huayi-qb.records.v1';
  const BACKUP_KEY = 'huayi-qb.records.before-dedup.v1';
  const OPTION_REPAIR_BACKUP_KEY = 'huayi-qb.records.before-duplicate-option-repair.v1';
  const IMAGE_UPGRADE_BACKUP_KEY = 'huayi-qb.records.before-image-upgrade.v1';
  const JUDGE_EVIDENCE_BACKUP_KEY = 'huayi-qb.records.before-judge-evidence-repair.v1';
  const RESET_KEY = 'huayi-qb.library-reset.v1';
  const LIBRARY_KEYS = [RECORDS_KEY, BACKUP_KEY, OPTION_REPAIR_BACKUP_KEY, IMAGE_UPGRADE_BACKUP_KEY, JUDGE_EVIDENCE_BACKUP_KEY];
  const DEFAULTS = { mode: 'hidden', keepLauncher: false, copyEnabled: true, collecting: true, tab: 'search' };
  const pageWindow = typeof unsafeWindow !== 'undefined' ? unsafeWindow : window;
  const rawStorage = {
    get(key, fallback) {
      if (typeof GM_getValue === 'function') return GM_getValue(key, fallback);
      const raw = localStorage.getItem(key);
      return raw === null ? fallback : JSON.parse(raw);
    },
    set(key, value) {
      if (typeof GM_setValue === 'function') return GM_setValue(key, value);
      localStorage.setItem(key, JSON.stringify(value));
    },
    remove(key) {
      if (typeof GM_deleteValue === 'function') return GM_deleteValue(key);
      if (typeof GM_setValue === 'function') return GM_setValue(key, null);
      localStorage.removeItem(key);
    }
  };
  function readGeneration() {
    const marker = rawStorage.get(RESET_KEY, null);
    if (marker === null) return '';
    if (marker?.schemaVersion !== 1 || typeof marker.generation !== 'string' || !/^[a-zA-Z0-9-]{1,100}$/.test(marker.generation)) {
      throw new Error('题库重置标记异常，请使用“重置全部题库”重新初始化');
    }
    return marker.generation;
  }
  const scopedKey = (key, generation) => generation ? `${key}.reset.${generation}` : key;
  let libraryGeneration = '', generationError = '';
  try { libraryGeneration = readGeneration(); } catch (error) { generationError = error.message; }
  // After a reset, even a still-open pre-upgrade tab can only write to an
  // obsolete namespace. Never migrate those legacy values into the new library.
  const storage = {
    get: (key, fallback) => rawStorage.get(scopedKey(key, libraryGeneration), fallback),
    set: (key, value) => rawStorage.set(scopedKey(key, libraryGeneration), value)
  };
  let rawConfig;
  try { rawConfig = storage.get(CONFIG_KEY, {}); } catch (_) { rawConfig = {}; }
  const config = { ...DEFAULTS, ...(rawConfig && typeof rawConfig === 'object' ? rawConfig : {}) };
  if (!['open', 'collapsed', 'hidden'].includes(config.mode)) config.mode = 'open';
  if (!['search', 'library', 'auto', 'settings'].includes(config.tab)) config.tab = 'search';
  ['keepLauncher', 'copyEnabled', 'collecting'].forEach(key => { if (typeof config[key] !== 'boolean') config[key] = DEFAULTS[key]; });
  // Every new page starts completely hidden, including upgrades from older settings.
  config.mode = 'hidden';
  config.keepLauncher = false;
  if (generationError) config.collecting = false;
  let records = [];
  let recordsDirty = false;
  let loadError = generationError;
  let cleanupNotice = '';
  let storedRecordsText = '';
  let saveIdle = null;
  const SAVE_DELAY = 800;
  function ensureCleanupBackup(original) {
    const existing = storage.get(BACKUP_KEY, null);
    if (existing === null) storage.set(BACKUP_KEY, { schemaVersion: 1, savedAt: new Date().toISOString(), records: original });
    else if (!existing || !Array.isArray(existing.records)) throw new Error('去重备份结构异常，已保留原题库并停止覆盖');
  }
  function repairAnswerConflicts(original) {
    if (!original.some(record => record?.answerStatus === 'conflict' && Array.isArray(record.conflicts) && record.conflicts.some(item =>
      item?.reason === '正确选项ID与正确答案内容不一致'))) return { records: original, repaired: [] };
    const result = QBCore.repairDuplicateOptionConflicts(original);
    if (!result.repaired.length) return result;
    const existing = storage.get(OPTION_REPAIR_BACKUP_KEY, null);
    if (existing !== null && (!existing || existing.schemaVersion !== 1 || !Array.isArray(existing.records))) {
      throw new Error('答案误报修复备份结构异常，已停止修复');
    }
    // Preserve every original version, including later imports and other tabs.
    // Back up before returning repaired data to any caller that may persist it.
    const originals = existing ? [...existing.records] : [];
    const signatures = new Set(originals.map(record => JSON.stringify(record)));
    for (const item of result.repaired) {
      const signature = JSON.stringify(item.original);
      if (!signatures.has(signature)) { signatures.add(signature); originals.push(item.original); }
    }
    storage.set(OPTION_REPAIR_BACKUP_KEY, { schemaVersion: 1, savedAt: existing?.savedAt || new Date().toISOString(), records: originals });
    return result;
  }
  function repairJudgeEvidence(original) {
    const result = QBCore.repairLegacyJudgeAnswers(original);
    if (!result.changed.length) return result;
    const existing = storage.get(JUDGE_EVIDENCE_BACKUP_KEY, null);
    if (existing !== null && (!existing || existing.schemaVersion !== 1 || !Array.isArray(existing.records))) {
      throw new Error('判断题答案核验备份结构异常，已停止覆盖');
    }
    const originals = existing ? [...existing.records] : [];
    const signatures = new Set(originals.map(record => JSON.stringify(record)));
    for (const item of result.changed) {
      const signature = JSON.stringify(item.original);
      if (!signatures.has(signature)) { signatures.add(signature); originals.push(item.original); }
    }
    // Retain every previous value before cleared or restored answers reach persistence.
    const backup = { schemaVersion: 1, savedAt: existing?.savedAt || new Date().toISOString(), records: originals };
    storage.set(JUDGE_EVIDENCE_BACKUP_KEY, backup);
    if (JSON.stringify(storage.get(JUDGE_EVIDENCE_BACKUP_KEY, null)) !== JSON.stringify(backup)) {
      throw new Error('判断题答案核验备份未能完整保存，已停止覆盖');
    }
    return result;
  }
  function imageReplacementSignature(value, includeQuestionIdentity = true) {
    const record = QBCore.normalizeRecord(value);
    return JSON.stringify([includeQuestionIdentity ? record.key : record.bankId, record.type, record.stem,
      record.options.map(option => JSON.stringify([option.id, option.text])).sort(),
      [...record.correctOptionIds].sort(), [...record.answerTexts].sort(), record.answerStatus]);
  }
  function imageUpgradeBackup() {
    const backup = storage.get(IMAGE_UPGRADE_BACKUP_KEY, null);
    if (backup !== null && (!backup || backup.schemaVersion !== 1 || !Array.isArray(backup.records) || !Array.isArray(backup.migrations))) {
      throw new Error('内容补全备份结构异常，已停止覆盖');
    }
    return backup;
  }
  function ensureImageUpgradeBackup(upgraded) {
    if (!upgraded.length) return;
    const previous = imageUpgradeBackup();
    const stored = storage.get(RECORDS_KEY, []);
    if (!Array.isArray(stored)) throw new Error('现有题库结构异常，已停止内容补全');
    const originals = previous ? [...previous.records] : [], migrations = previous ? [...previous.migrations] : [];
    const signatures = new Set(originals.map(record => JSON.stringify(QBCore.normalizeRecord(record))));
    for (const item of upgraded) {
      const canonical = QBCore.normalizeRecord(item.original);
      // Compaction may just have assigned occurrence=0 in memory, without a
      // previous storage write. Capture that exact stored predecessor as well;
      // only this generated metadata may be absent, never content or answers.
      const versions = [item.original, ...stored.filter(value => {
        const record = QBCore.normalizeRecord(value);
        if (record.key !== canonical.key) return false;
        if (record.contentOccurrence == null && canonical.contentOccurrence != null) record.contentOccurrence = canonical.contentOccurrence;
        return JSON.stringify(QBCore.normalizeRecord(record)) === JSON.stringify(canonical);
      })];
      for (const value of versions) {
        const original = QBCore.normalizeRecord(value), originalSignature = JSON.stringify(original);
        if (!signatures.has(originalSignature)) { signatures.add(originalSignature); originals.push(value); }
        const migration = { originalKey: original.key, originalSignature, replacementKey: item.replacement.key,
          replacementSignature: imageReplacementSignature(item.replacement), replacementQuestionId: item.replacement.questionId,
          replacementContentSignature: imageReplacementSignature(item.replacement, false), kind: item.kind || 'image', bankId: item.bankId,
          batchId: item.batchId, expectedCount: item.expectedCount, questionIndex: item.questionIndex };
        if (!migrations.some(value => JSON.stringify(value) === JSON.stringify(migration))) migrations.push(migration);
      }
    }
    storage.set(IMAGE_UPGRADE_BACKUP_KEY, { schemaVersion: 1, savedAt: previous?.savedAt || new Date().toISOString(), records: originals, migrations });
  }
  function removeBackedUpImagePredecessors(original, replacements) {
    const backup = imageUpgradeBackup();
    if (!backup) return original;
    // A stale tab can reintroduce the exact pre-upgrade record while saving.
    // Remove only a durably backed-up version with its unchanged, confirmed
    // replacement present. Different answers or newly changed old data survive.
    const backups = new Set(backup.records.map(record => JSON.stringify(QBCore.normalizeRecord(record))));
    return original.filter(value => {
      const record = QBCore.normalizeRecord(value), signature = JSON.stringify(record);
      return !backup.migrations.some(item => item.originalKey === record.key && item.originalSignature === signature && backups.has(signature) &&
        replacements.some(replacement => replacement.answerStatus === 'confirmed' && replacement.questionIdAliases?.includes(record.questionId) &&
          ((replacement.key === item.replacementKey && imageReplacementSignature(replacement) === item.replacementSignature) ||
            (item.replacementContentSignature && replacement.bankId === item.bankId &&
              (replacement.questionId === item.replacementQuestionId || replacement.questionIdAliases?.includes(item.replacementQuestionId)) &&
              imageReplacementSignature(replacement, false) === item.replacementContentSignature))));
    });
  }
  function loadRecords() {
    try {
      if (generationError) throw new Error(generationError);
      const saved = storage.get(RECORDS_KEY, []);
      if (!Array.isArray(saved)) throw new Error('本地题库格式不正确');
      storedRecordsText = JSON.stringify(saved);
      const retained = removeBackedUpImagePredecessors(saved, saved);
      const judgeRepair = repairJudgeEvidence(retained);
      const repaired = repairAnswerConflicts(judgeRepair.records);
      const compacted = QBCore.compactRecords(QBCore.upsert([], repaired.records));
      records = compacted.records;
      const removed = retained.length - records.length;
      if (retained.length < saved.length) recordsDirty = true;
      if (removed > 0) {
        ensureCleanupBackup(saved);
        recordsDirty = true;
        cleanupNotice = `已合并 ${removed} 条重复加载记录，原始数据已备份。`;
      }
      if (repaired.repaired.length) {
        recordsDirty = true;
        cleanupNotice += `${cleanupNotice ? ' ' : ''}已恢复 ${repaired.repaired.length} 道重复选项文字造成的答案误报，修复前记录已备份。`;
      }
      if (judgeRepair.changed.length) {
        recordsDirty = true;
        cleanupNotice += `${cleanupNotice ? ' ' : ''}已核验 ${judgeRepair.changed.length} 条判断题答案，缺少标准答案依据的记录已改为待补，原值已独立备份。`;
      }
    } catch (error) { loadError = `本地题库读取失败：${error.message}。请先保留已有备份。`; }
  }
  loadRecords();
  let root, shadow, panel, launcher, resultBox, statusBox;
  let networkEnabled = ['www.shhuayi-elearning.cn', 'shhuayi-elearning.cn'].includes(window.location.hostname);
  let saveTimer, searchTimer, query = '', scope = networkEnabled ? '__current__' : '', searchScope = scope, searchField = 'all';
  let activeBank = null, importing = false, importAttempt = 0;
  let status = loadError || cleanupNotice || '可输入文字或划选题干检索。';
  let storageError = false;
  let mounted = false;
  let recordsListener = null;
  let collector = null, collectorInitError = '';
  const createAdapter = () => QBAdapter.create({ window: pageWindow, document, onQuestions: receive, onStatus: adapterStatus, onBankChange: bankChanged, observeNetwork: networkEnabled });
  let adapter = createAdapter();
  const getLiveRecords = () => { synchronizeReset(); return records; };
  const autoAnswer = QBAuto.create({ window: pageWindow, document, core: QBCore, getRecords: getLiveRecords, getQuestion: currentQuestion, getBank: currentBank,
    onStatus: message => { tell(message); }, onChange: () => { renderAuto(); } });
  try {
    if (typeof QBCollector !== 'undefined') collector = QBCollector.create({ window: pageWindow, document, core: QBCore,
      getRecords: getLiveRecords, getQuestion: currentQuestion, getBank: currentBank,
      isCollecting: () => networkEnabled && config.collecting && !loadError && !storageError && !importing,
      onChange: () => { if (mounted && config.mode === 'open' && config.tab === 'auto') renderAuto(); } });
  } catch (error) { collectorInitError = `练习补齐模块加载失败：${error.message}`; }

  function stopCollector(message) {
    if (!collector) return;
    try { if (collector.getState().active) collector.stop(message); }
    catch (error) { tell(`停止练习补齐失败：${error.message}`, true); }
  }
  function collectorBlockReason() {
    if (!collector) return collectorInitError || '练习补齐模块未加载，请更新完整脚本。';
    if (!networkEnabled || !['www.shhuayi-elearning.cn', 'shhuayi-elearning.cn'].includes(window.location.hostname)) return '仅支持华谊网站当前判断题练习。';
    if (!config.collecting) return '请先继续题库采集，再启动练习补齐。';
    if (loadError || storageError || importing) return '题库读取、保存或导入尚未就绪，练习补齐已停用。';
    const bank = currentBank();
    if (!bank?.bankId || bank.loading || currentQuestion()?.type !== 'judge' ||
      !document.querySelector('.yxtulcdsdk-pc-marking-main .yxtulcdsdk-form[practice]')) return '请先打开当前判断题的正常练习页面。';
    return '';
  }
  function startCollector() {
    const blocked = collectorBlockReason();
    if (blocked) { tell(blocked, true); renderAuto(); return; }
    try {
      autoAnswer.setEnabled(false);
      collector.start();
      renderAuto();
    } catch (error) {
      stopCollector(`练习补齐失败：${error.message}`);
      tell(`练习补齐失败：${error.message}`, true);
      renderAuto();
    }
  }

  function activateKnownPage() {
    if (!networkEnabled && document.querySelector('.yxtulcdsdk-pc-marking-main')) {
      adapter.stop();
      adapter.setCopyEnabled(false);
      networkEnabled = true;
      scope = '__current__'; searchScope = '__current__';
      adapter = createAdapter();
      if (config.collecting) adapter.start();
      adapter.setCopyEnabled(Boolean(config.copyEnabled));
    }
  }

  function bankChanged(bank) {
    if (!bank || (!bank.bankName && !bank.bankId)) {
      stopCollector('当前练习题库已离开，练习补齐已停止。');
      if (activeBank) {
        activeBank = null; scope = ''; searchScope = '';
        renderVisible();
      }
      return;
    }
    const previous = activeBank;
    const sameName = previous && bankNameKey(previous.bankName) === bankNameKey(bank.bankName);
    const identityChanged = previous && (!sameName || (previous.taskId && bank.taskId && previous.taskId !== bank.taskId) || (previous.bankId && bank.bankId && previous.bankId !== bank.bankId));
    const changed = JSON.stringify(previous) !== JSON.stringify(bank);
    activeBank = { ...bank };
    if (identityChanged || bank.loading) stopCollector('题库正在切换，练习补齐已停止。');
    if (identityChanged) { scope = '__current__'; searchScope = '__current__'; }
    if (changed) renderVisible();
  }

  function adapterStatus(value) {
    const message = typeof value === 'string' ? value : value && value.message;
    if (message && !storageError) { status = message; renderStatus(); }
  }
  function cancelPendingSave() {
    clearTimeout(saveTimer);
    saveTimer = null;
    if (saveIdle !== null) { window.cancelIdleCallback?.(saveIdle); saveIdle = null; }
  }
  function adoptGeneration(generation) {
    cancelPendingSave();
    stopCollector('题库已重置，练习补齐已停止。');
    autoAnswer.setEnabled(false);
    config.collecting = false;
    if (adapter.clearCache) adapter.clearCache();
    else adapter.stop();
    libraryGeneration = generation;
    generationError = ''; loadError = ''; storageError = false; cleanupNotice = '';
    records = []; recordsDirty = false; storedRecordsText = '';
    importAttempt++; importing = false;
    clearTimeout(searchTimer);
    query = ''; scope = networkEnabled ? '__current__' : ''; searchScope = scope; searchField = 'all';
    if (shadow) {
      shadow.getElementById('qb-search').value = '';
      shadow.getElementById('qb-search-field').value = 'all';
      shadow.getElementById('qb-import-file').value = '';
      shadow.querySelector('[data-action="import"]').disabled = false;
    }
    loadRecords();
    watchRecords();
    if (recordsDirty && !loadError) schedulePersist();
    tell(loadError || '题库已重置并同步，采集与自动答题已关闭。请重新导入可信题库。', Boolean(loadError));
    renderVisible(); renderAuto();
  }
  function synchronizeReset() {
    try {
      const generation = readGeneration();
      if (generation === libraryGeneration && !generationError) return true;
      adoptGeneration(generation);
    } catch (error) {
      generationError = error.message;
      loadError = `题库重置状态读取失败：${error.message}`;
      cancelPendingSave();
      config.collecting = false;
      stopCollector('题库重置状态异常，练习补齐已停止。');
      autoAnswer.setEnabled(false); adapter.stop();
      tell(loadError, true);
    }
    return false;
  }
  function resetLibrary() {
    synchronizeReset();
    if (!window.confirm(`确定重置全部本地题库吗？\n\n将清空全部 ${records.length} 道题、答案、冲突及历史修复备份，并暂停采集和自动答题。\n如需保留，请先取消并导出 JSON 备份。重置后可重新导入可信题库。`)) return;
    const previousGeneration = libraryGeneration;
    const generation = window.crypto?.randomUUID?.() || `${Date.now().toString(36)}-${Math.random().toString(36).slice(2)}`;
    const nextConfig = { ...config, collecting: false };
    const staged = [scopedKey(RECORDS_KEY, generation), scopedKey(CONFIG_KEY, generation)];
    try {
      // Prepare and verify an empty library before publishing the reset marker.
      // Failure here leaves the existing library and all its backups untouched.
      rawStorage.set(staged[0], []);
      rawStorage.set(staged[1], nextConfig);
      if (JSON.stringify(rawStorage.get(staged[0], null)) !== '[]' ||
        JSON.stringify(rawStorage.get(staged[1], null)) !== JSON.stringify(nextConfig)) throw new Error('空题库未能完整保存');
      rawStorage.set(RESET_KEY, { schemaVersion: 1, generation, resetAt: new Date().toISOString() });
      if (readGeneration() !== generation) throw new Error('重置状态未能保存或已被另一标签页更新');
    } catch (error) {
      // A storage provider may throw after writing; follow the published marker
      // in that case, rather than letting this tab keep saving pre-reset data.
      const unchanged = synchronizeReset();
      if (unchanged) for (const key of staged) { try { rawStorage.remove(key); } catch (_) {} }
      tell(`重置未完成：${error.message}。请检查油猴存储后重试。`, true);
      return;
    }
    adoptGeneration(generation);
    const obsolete = new Set([...LIBRARY_KEYS, CONFIG_KEY].flatMap(key => [key, scopedKey(key, previousGeneration)]));
    let cleanupFailed = false;
    for (const key of obsolete) {
      try {
        rawStorage.remove(key);
        if (rawStorage.get(key, null) !== null) cleanupFailed = true;
      } catch (_) { cleanupFailed = true; }
    }
    tell(cleanupFailed ? '题库已重置；部分旧存储清理失败，已隔离且不会再读取。请检查油猴存储。' :
      '已清空全部题库及历史修复备份，采集与自动答题已关闭。请重新导入可信题库。', cleanupFailed);
  }
  function persistConfig() {
    if (!synchronizeReset()) return;
    try { storage.set(CONFIG_KEY, { ...config }); }
    catch (error) { tell(`设置保存失败：${error.message}`, true); }
  }
  function persistRecords() {
    if (!synchronizeReset()) return;
    cancelPendingSave();
    if (loadError || !recordsDirty) return;
    try {
      // Merge other tabs before writing; GM change events also refresh an open panel.
      const stored = storage.get(RECORDS_KEY, []);
      if (!Array.isArray(stored)) throw new Error('现有题库结构异常，已停止覆盖');
      const currentStoredText = JSON.stringify(stored);
      // Local records have already been validated when received/imported. Only
      // reconcile the whole library when another tab actually changed storage.
      if (currentStoredText !== storedRecordsText) {
        const retained = removeBackedUpImagePredecessors(stored, records);
        const compacted = QBCore.compactRecords(QBCore.upsert(repairAnswerConflicts(repairJudgeEvidence(retained).records).records, records));
        if (compacted.removed > 0) ensureCleanupBackup(stored);
        records = repairAnswerConflicts(repairJudgeEvidence(compacted.records).records).records;
      }
      const nextStoredText = JSON.stringify(records);
      if (nextStoredText !== currentStoredText) storage.set(RECORDS_KEY, records);
      storedRecordsText = nextStoredText;
      recordsDirty = false;
      storageError = false;
    } catch (error) {
      storageError = true;
      stopCollector('题库保存失败，练习补齐已停止，请先备份数据。');
      tell(`保存失败：${error.message}。当前内存数据仍可导出，请及时备份。`, true);
    }
  }
  function schedulePersist() {
    if (saveTimer != null || saveIdle !== null) return;
    saveTimer = setTimeout(() => {
      saveTimer = null;
      if (typeof window.requestIdleCallback === 'function') {
        saveIdle = window.requestIdleCallback(() => { saveIdle = null; persistRecords(); }, { timeout: 1000 });
      } else persistRecords();
    }, SAVE_DELAY);
  }
  let observationIndexSource = null, observationIndex;
  function redundantDOMObservation(record) {
    if (record.source?.kind !== 'dom' || record.answerStatus !== 'missing' || record.explanation || !record.bankId || !record.questionId) return false;
    if (observationIndexSource !== records) {
      observationIndexSource = records;
      observationIndex = new Map();
      for (const saved of records) for (const id of new Set([saved.questionId, ...(saved.questionIdAliases || [])].filter(Boolean))) {
        const key = JSON.stringify([saved.bankId, id]);
        observationIndex.set(key, observationIndex.has(key) && observationIndex.get(key) !== saved ? null : saved);
      }
    }
    const saved = observationIndex.get(JSON.stringify([record.bankId, record.questionId]));
    const flat = value => String(value || '').replace(/\s+/gu, '');
    if (!saved || saved.answerStatus !== 'confirmed' || saved.type !== record.type || flat(saved.stem) !== flat(record.stem) ||
      (record.questionIndex != null && record.questionIndex !== saved.questionIndex) ||
      (record.contentOccurrence != null && record.contentOccurrence !== saved.contentOccurrence)) return false;
    return JSON.stringify(saved.options.map(option => flat(option.text)).sort()) ===
      JSON.stringify(record.options.map(option => flat(option.text)).sort());
  }
  function receive(incoming, context = {}) {
    if (!synchronizeReset()) return;
    if (!Array.isArray(incoming) || !incoming.length || loadError) return;
    try {
      incoming = incoming.filter(record => !redundantDOMObservation(record));
      if (!incoming.length) return;
      incoming = repairAnswerConflicts(repairJudgeEvidence(incoming).records).records;
      const bank = currentBank();
      const upgradeContext = {
        bankId: !bank?.loading && (context.currentBankId || context.bankId) === bank?.bankId ? bank.bankId : '',
        expectedCount: context.pageQuestionCount, fullSnapshot: context.fullSnapshot === true
      };
      if (upgradeContext.fullSnapshot && Number.isSafeInteger(upgradeContext.expectedCount)) {
        const imageUpgrade = QBCore.upgradeLegacyImageRecords(records, incoming, upgradeContext);
        const contentUpgrade = QBCore.upgradeLegacyMathEntities(imageUpgrade.existing, imageUpgrade.incoming, upgradeContext);
        ensureImageUpgradeBackup([...imageUpgrade.upgraded, ...contentUpgrade.upgraded]);
        records = contentUpgrade.existing;
        incoming = contentUpgrade.incoming;
      }
      const namesById = new Map();
      incoming.forEach(record => {
        if (!record.bankId || record.source?.kind !== 'network' || !record.bankName || record.bankName === '未命名题库') return;
        if (!namesById.has(record.bankId)) namesById.set(record.bankId, new Set());
        namesById.get(record.bankId).add(record.bankName);
      });
      // A newly observed, explicit bank ID/name pair can repair an old stale
      // title for that same ID. Never infer a rename from question type or text.
      if (namesById.size) records = records.map(record => {
        const names = record.bankId && namesById.get(record.bankId);
        return names?.size === 1 && record.bankName !== [...names][0] ? QBCore.normalizeRecord({ ...record, bankName: [...names][0] }) : record;
      });
      const expanded = QBCore.upsert(records, incoming);
      const compacted = QBCore.compactRecords(expanded);
      if (compacted.removed > 0) ensureCleanupBackup(expanded);
      records = repairAnswerConflicts(repairJudgeEvidence(compacted.records).records).records;
      recordsDirty = true;
      schedulePersist();
      renderVisible();
    } catch (error) { stopCollector('题目未能保存，练习补齐已停止。'); tell(`这批题目未保存：${error.message}`, true); }
  }
  function tell(message, error = false) {
    status = message;
    if (statusBox) statusBox.dataset.error = String(error);
    renderStatus();
  }
  function renderStatus() {
    if (statusBox) statusBox.textContent = status;
  }
  function node(tag, className, text) {
    const element = document.createElement(tag);
    if (className) element.className = className;
    if (text !== undefined) element.textContent = text;
    return element;
  }
  function setMode(mode) {
    config.mode = mode;
    persistConfig();
    renderMode();
    if (mode === 'open' && config.tab === 'search') shadow?.getElementById('qb-search').focus();
  }
  function renderMode() {
    if (!panel) return;
    panel.hidden = config.mode === 'hidden';
    panel.classList.toggle('collapsed', config.mode === 'collapsed');
    launcher.hidden = true;
    const collapse = shadow.querySelector('[data-action="collapse"]');
    collapse.textContent = config.mode === 'collapsed' ? '展开' : '收起';
    collapse.setAttribute('aria-expanded', String(config.mode !== 'collapsed'));
    if (config.mode === 'open') renderVisible();
  }
  function selectTab(tab) {
    config.tab = tab;
    persistConfig();
    shadow.querySelectorAll('[data-tab]').forEach(button => {
      const selected = button.dataset.tab === tab;
      button.setAttribute('aria-selected', String(selected));
      button.classList.toggle('active', selected);
    });
    shadow.querySelectorAll('[data-view]').forEach(view => { view.hidden = view.dataset.view !== tab; });
    renderVisible();
  }
  function renderVisible() {
    if (!mounted || config.mode !== 'open') return;
    refreshScope(); renderStats(); renderCurrent();
    if (config.tab === 'search') renderResults();
    if (config.tab === 'auto') renderAuto();
    renderStatus();
  }
  function bankKey(record) { return String(record.bankId || record.bankName || ''); }
  function bankNameKey(name) { return String(name || '').replace(/\s+/g, ''); }
  let catalogSource = null, catalogCache;
  function bankCatalog() {
    if (catalogSource === records) return catalogCache;
    const namedIds = new Map();
    records.forEach(record => {
      if (!record.bankId) return;
      const name = bankNameKey(record.bankName);
      if (!namedIds.has(name)) namedIds.set(name, new Set());
      namedIds.get(name).add(record.bankId);
    });
    const catalog = new Map();
    records.forEach(record => {
      const ids = namedIds.get(bankNameKey(record.bankName));
      const key = !record.bankId && ids?.size === 1 ? [...ids][0] : bankKey(record);
      if (!catalog.has(key)) catalog.set(key, { key, name: record.bankName || record.bankId || '未命名题库', count: 0 });
      catalog.get(key).count++;
    });
    catalogSource = records;
    catalogCache = [...catalog.values()];
    return catalogCache;
  }
  function currentQuestion() {
    try { return adapter.getCurrentQuestion(); } catch (_) { return null; }
  }
  function currentBank() {
    try { return adapter.getCurrentBank?.() || activeBank || currentQuestion(); }
    catch (_) { return activeBank; }
  }
  function sameBankScope(record, anchor, knownIds) {
    if (record.bankId && anchor.bankId) return record.bankId === anchor.bankId;
    const name = String(anchor.bankName || '').replace(/\s+/g, '');
    if (!name || name === '未命名题库' || String(record.bankName || '').replace(/\s+/g, '') !== name) return false;
    const namedIds = knownIds || new Set(records.filter(item => item.bankId && bankNameKey(item.bankName) === name).map(item => item.bankId));
    if (anchor.bankId) namedIds.add(anchor.bankId);
    // A human CSV often has a bank name only. Include it only when that name
    // identifies one known bank; identical names across bank IDs stay separate.
    return namedIds.size <= 1;
  }
  function scopedRecords(selectedScope = scope) {
    if (!selectedScope) return records;
    const isCurrent = selectedScope === '__current__';
    const anchor = isCurrent ? currentBank() : records.find(record => bankKey(record) === selectedScope);
    if (!anchor) return [];
    const namedIds = new Set(records.filter(item => item.bankId && bankNameKey(item.bankName) === bankNameKey(anchor.bankName)).map(item => item.bankId));
    if (anchor.bankId) namedIds.add(anchor.bankId);
    return records.filter(record => (!isCurrent && bankKey(record) === selectedScope) || sameBankScope(record, anchor, namedIds));
  }
  function scopeName(selectedScope = scope) {
    if (selectedScope === '') return '全部题库';
    if (selectedScope === '__current__') return currentBank()?.bankName || '当前网页未识别题库';
    const anchor = records.find(record => bankKey(record) === selectedScope);
    return anchor?.bankName || '未命名题库';
  }
  function refreshScope() {
    if (!shadow || config.mode !== 'open') return;
    const banks = new Map(bankCatalog().map(bank => [bank.key, bank.name]));
    if (scope && scope !== '__current__' && !banks.has(scope)) scope = '__current__';
    if (searchScope && searchScope !== '__current__' && !banks.has(searchScope)) searchScope = '__current__';
    const names = [...banks.values()];
    const options = [['__current__', `当前题库：${scopeName('__current__')}`], ['', `全部题库（${records.length}题）`], ...[...banks].map(([key, name]) => [key, names.filter(value => value === name).length > 1 ? `${name}（${key === name ? '无ID' : key}）` : name])];
    ['qb-scope', 'qb-search-scope'].forEach(id => {
      const select = shadow.getElementById(id);
      const signature = JSON.stringify(options);
      if (select.dataset.signature !== signature) {
        select.dataset.signature = signature;
        select.replaceChildren();
        options.forEach(([value, label]) => {
          const option = node('option', '', label); option.value = value; option.title = label; select.append(option);
        });
      }
      select.value = id === 'qb-scope' ? scope : searchScope;
    });
  }
  function renderStats() {
    if (!shadow || config.mode !== 'open') return;
    const selected = scopedRecords();
    const confirmed = selected.filter(record => record.answerStatus === 'confirmed').length;
    const conflicts = selected.filter(record => record.answerStatus === 'conflict').length;
    [['total', selected.length], ['confirmed', confirmed], ['missing', selected.length - confirmed - conflicts], ['conflicts', conflicts]].forEach(([name, count]) => {
      shadow.getElementById(`qb-stat-${name}`).textContent = count.toLocaleString('zh-CN');
    });
    const exportName = scopeName();
    shadow.getElementById('qb-export-name').textContent = exportName;
    shadow.getElementById('qb-export-name').title = exportName;
    const catalog = bankCatalog();
    shadow.getElementById('qb-library-summary').textContent = `本地共保存 ${catalog.length} 个题库、${records.length} 道题。上方统计与导出均按所选范围。`;
    const bankList = shadow.getElementById('qb-bank-list');
    bankList.replaceChildren();
    catalog.forEach(bank => {
      const item = node('div', 'bank-row');
      item.append(node('span', '', bank.name), node('strong', '', `${bank.count} 题`));
      bankList.append(item);
    });
    shadow.getElementById('qb-export-preview').textContent = selected.length ? `文件名：${exportFilename(exportName, selected.length, 'csv')}` : '该范围暂无题目；不会导出其他题库。';
    const button = shadow.querySelector('[data-action="toggle-capture"]');
    button.textContent = config.collecting ? '暂停采集' : '继续采集';
    const indicator = shadow.getElementById('qb-capture-state');
    indicator.textContent = config.collecting ? '采集中' : '已暂停';
    indicator.classList.toggle('paused', !config.collecting);
  }
  function renderCurrent() {
    if (!shadow || config.mode !== 'open') return;
    const bank = currentBank();
    const current = currentQuestion();
    const known = Boolean(bank?.bankName || bank?.bankId);
    const name = bank?.bankName || '通用网页 · 本地题库';
    shadow.getElementById('qb-context-name').textContent = name;
    shadow.getElementById('qb-context-name').title = name;
    const pool = scopedRecords('__current__');
    shadow.getElementById('qb-context-count').textContent = known ? `${bank?.loading ? '切换中 · ' : ''}本库已采集 ${pool.length} 题 · 已确认 ${pool.filter(record => record.answerStatus === 'confirmed').length} 题` : `本地共 ${records.length} 题 · 可划词或输入文字搜索`;
    shadow.getElementById('qb-page-total').textContent = known && Number.isSafeInteger(bank?.questionCount) && bank.questionCount > 0 ? ` · 页面 ${bank.questionCount} 题` : '';
    shadow.getElementById('qb-current-title').textContent = bank?.loading ? '题库切换中，等待当前题目加载。' : current?.stem || '打开练习题后，这里显示当前题目。';
    shadow.getElementById('qb-current-bank').textContent = name;
  }
  function renderAuto() {
    if (!mounted || !shadow || config.mode !== 'open' || config.tab !== 'auto') return;
    const state = autoAnswer.getState();
    shadow.getElementById('qb-auto-enabled').checked = state.enabled;
    shadow.getElementById('qb-auto-status').textContent = state.message || '自动答题尚未开启。可先点击“答当前题”。';
    shadow.getElementById('qb-auto-count').textContent = `本页已选择 ${state.answeredCount || 0} 题 · 已跳过 ${state.skippedCount || 0} 题`;
    shadow.querySelector('[data-action="auto-answer-current"]').disabled = Boolean(state.busy);
    const collection = collector?.getState() || { active: false, answered: 0, skipped: 0, current: 0, total: 0 };
    const blocked = collectorBlockReason();
    shadow.getElementById('qb-collector-status').textContent = collection.message || blocked || '练习补齐默认关闭；仅在点击启动后运行。';
    shadow.getElementById('qb-collector-count').textContent = `本次已作答 ${collection.answered || 0} 题 · 已跳过 ${collection.skipped || 0} 题 · 当前 ${collection.current || 0}/${collection.total || 0}`;
    shadow.querySelector('[data-action="start-collector"]').disabled = Boolean(collection.active || blocked);
    shadow.querySelector('[data-action="stop-collector"]').disabled = !collection.active;
  }
  function matchesCurrentQuestion(record, current) {
    if (!current || record.type !== current.type) return false;
    const flat = value => String(value || '').trim().replace(/\s+/gu, '');
    const stem = value => flat(String(value || '').replace(/^(?:第\s*\d+\s*题[\s、.．:：]*|\d+\s*[、．]\s*|\d+\.\s+)/u, ''));
    if (record.bankId && current.bankId && record.bankId !== current.bankId) return false;
    if (!(record.bankId && record.bankId === current.bankId) && record.bankName && current.bankName &&
      record.bankName !== '未命名题库' && current.bankName !== '未命名题库' && bankNameKey(record.bankName) !== bankNameKey(current.bankName)) return false;
    if (Number.isSafeInteger(record.questionIndex) && Number.isSafeInteger(current.questionIndex) && record.questionIndex !== current.questionIndex) return false;
    return stem(record.stem) === stem(current.stem) && JSON.stringify((record.options || []).map(option => flat(option.text)).sort()) ===
      JSON.stringify((current.options || []).map(option => flat(option.text)).sort());
  }
  function renderResults() {
    if (!resultBox || config.mode !== 'open' || config.tab !== 'search') return;
    resultBox.replaceChildren();
    const pool = scopedRecords(searchScope);
    const current = currentQuestion();
    const currentRecords = current ? pool.filter(record => matchesCurrentQuestion(record, current)) : [];
    const matches = [];
    if (query.trim()) {
      const seen = new Set();
      // A complete match to the displayed question precedes other keyword candidates.
      for (const item of [...QBCore.search(currentRecords, query, { limit: 50, field: searchField }), ...QBCore.search(pool, query, { limit: 50, field: searchField })]) {
        if (seen.has(item.record.key)) continue;
        seen.add(item.record.key); matches.push(item);
        if (matches.length === 50) break;
      }
    }
    const confirmedCurrent = currentRecords.filter(record => record.answerStatus === 'confirmed')
      .map(record => QBCore.mapAnswers(record, current));
    const currentAnswerAgrees = confirmedCurrent.length > 0 && !currentRecords.some(record => record.answerStatus === 'conflict') &&
      confirmedCurrent.every(mapping => mapping.status === 'matched') &&
      new Set(confirmedCurrent.map(mapping => JSON.stringify([...mapping.labels].sort()))).size === 1;
    const searchName = scopeName(searchScope);
    shadow.getElementById('qb-query-state').textContent = query.trim() ? `${searchName} · ${pool.length} 题 · 显示 ${matches.length} 个结果${matches.length === 50 ? '（最多50条，请细化关键词）' : ''}` : `${searchName} · 可输入题干、选项或标准答案关键词`;
    if (!matches.length) {
      const empty = node('div', 'empty');
      empty.append(node('strong', '', query.trim() ? '没有找到匹配题目' : '输入文字，查找正确答案'), node('p', '', query.trim() ? '可切换到全部题库、更换关键词，或导入其他题库。' : '支持输入、粘贴或划选文字；按回车或点搜索查询。多个关键词可用空格分隔。'));
      resultBox.append(empty);
      return;
    }
    matches.forEach(({ record, match, matchedField }) => {
      const card = node('article', 'result');
      const meta = node('div', 'meta');
      const statusText = record.answerStatus === 'confirmed' ? '已确认' : record.answerStatus === 'conflict' ? '答案冲突' : '待补答案';
      const matchLabel = matchedField === 'options' ? '选项匹配' : matchedField === 'answer' ? '答案匹配' : ({ exact: '题干一致', partial: '文字匹配', similar: '相似候选' })[match] || '候选';
      const currentMatches = matchesCurrentQuestion(record, current);
      const mapped = currentMatches && record.answerStatus === 'confirmed' ? QBCore.mapAnswers(record, current) : null;
      const verifiedCurrent = currentMatches && currentAnswerAgrees && mapped?.status === 'matched';
      meta.append(node('span', `badge ${record.answerStatus}`, statusText), node('span', '', `${({ single: '单选', multiple: '多选', judge: '判断' })[record.type] || '题目'} · ${currentMatches ? '当前题完整匹配' : matchLabel}`));
      card.append(meta, node('p', 'stem', record.stem));
      const answer = node('div', `answer ${record.answerStatus !== 'confirmed' ? 'pending' : ''}`);
      answer.append(node('span', 'answer-label', verifiedCurrent ? '本题正确答案' : record.answerStatus === 'missing' ? '标准答案' : '候选题答案'));
      if (record.answerStatus === 'confirmed') {
        const texts = record.answerTexts || [];
        answer.append(node('strong', '', texts.length ? texts.join('；') : '标准答案缺少文字，需核验选项'));
        if (verifiedCurrent && mapped.labels?.length) answer.append(node('span', 'mapping', `当前页面对应：${mapped.labels.join('、')}`));
        else answer.append(node('span', 'mapping', currentMatches ? '答案尚不能唯一对应当前题，请核对题干和来源。' : current ? '与当前题的题干或完整选项不同，请核对题干。' : '尚未识别当前完整题目，请核对题干。'));
      } else {
        answer.append(node('strong', '', record.answerStatus === 'conflict' ? '存在不同标准答案，需要核验' : record.type === 'judge' ? '标准答案未确认' : '尚未取得标准答案'));
        if (record.answerStatus === 'conflict' && record.conflicts?.length) answer.append(node('span', 'mapping', '冲突记录已保留在 JSON / CSV 备份中。'));
      }
      card.append(answer);
      if (matchedField === 'options') {
        const details = node('details', 'explanation');
        details.open = true;
        details.append(node('summary', '', '题目选项'));
        record.options.forEach(option => details.append(node('p', '', `${option.label}. ${option.text}`)));
        card.append(details);
      }
      if (record.explanation) {
        const details = node('details', 'explanation');
        details.append(node('summary', '', '查看解析'), node('p', '', record.explanation));
        card.append(details);
      }
      card.append(node('div', 'source', `${record.bankName || '未命名题库'}${record.questionId ? ` · ID ${record.questionId}` : ''}`));
      resultBox.append(card);
    });
  }
  function runSearch(text) {
    if (!synchronizeReset()) return;
    query = String(text || '').trim().slice(0, 4000);
    if (shadow) shadow.getElementById('qb-search').value = query;
    renderResults();
  }
  function download(contents, filename, mime) {
    const blob = new Blob([contents], { type: mime });
    const url = URL.createObjectURL(blob);
    const anchor = document.createElement('a');
    anchor.href = url; anchor.download = filename;
    (document.body || document.documentElement).append(anchor);
    anchor.click(); anchor.remove();
    setTimeout(() => URL.revokeObjectURL(url), 10000);
  }
  function safeFilename(value) {
    let name = String(value || '未命名题库').replace(/[<>:"/\\|?*\u0000-\u001f]/g, '_').replace(/\s+/g, ' ').trim().replace(/[. ]+$/, '');
    name = Array.from(name).slice(0, 110).join('');
    if (!name || /^(con|prn|aux|nul|com[1-9]|lpt[1-9])(?:\.|$)/i.test(name)) name = `题库_${name || '未命名'}`;
    return name;
  }
  function exportFilename(name, count, format, date = new Date()) {
    const parts = Object.fromEntries(new Intl.DateTimeFormat('en-CA', { timeZone: 'Asia/Shanghai', year: 'numeric', month: '2-digit', day: '2-digit' }).formatToParts(date).map(part => [part.type, part.value]));
    return `${safeFilename(name)}_${count}题_${parts.year}${parts.month}${parts.day}.${format}`;
  }
  function exportData(format) {
    if (!synchronizeReset()) return;
    const selected = scopedRecords();
    if (!selected.length) return tell('所选范围还没有题目，请先采集或导入。');
    const date = new Date();
    const bankName = scopeName();
    const filename = exportFilename(bankName, selected.length, format, date);
    if (format === 'csv') download(QBCore.toCSV(selected), filename, 'text/csv;charset=utf-8');
    else download(JSON.stringify({ schemaVersion: 1, exportedAt: date.toISOString(), bankName, records: selected }, null, 2), filename, 'application/json;charset=utf-8');
    tell(`已导出「${bankName}」${selected.length} 道题，其中 ${selected.filter(record => record.answerStatus === 'confirmed').length} 道有已确认答案。`);
  }
  function exportCleanupBackup() {
    if (!synchronizeReset()) return;
    const backup = storage.get(BACKUP_KEY, null);
    if (!backup || !Array.isArray(backup.records)) return tell('没有需要恢复的整理前备份。');
    download(JSON.stringify(backup, null, 2), exportFilename('题库整理前原始备份', backup.records.length, 'json'), 'application/json;charset=utf-8');
    tell(`已导出整理前的 ${backup.records.length} 条原始记录。`);
  }
  function exportOptionRepairBackup() {
    if (!synchronizeReset()) return;
    const backup = storage.get(OPTION_REPAIR_BACKUP_KEY, null);
    if (!backup || !Array.isArray(backup.records)) return tell('没有答案误报修复前的备份。');
    download(JSON.stringify(backup, null, 2), exportFilename('答案误报修复前原始备份', backup.records.length, 'json'), 'application/json;charset=utf-8');
    tell(`已导出答案误报修复前的 ${backup.records.length} 条原始记录。`);
  }
  function exportImageUpgradeBackup() {
    if (!synchronizeReset()) return;
    const backup = imageUpgradeBackup();
    if (!backup) return tell('没有内容补全前的备份。');
    download(JSON.stringify(backup, null, 2), exportFilename('内容补全前原始备份', backup.records.length, 'json'), 'application/json;charset=utf-8');
    tell(`已导出内容补全前的 ${backup.records.length} 条原始记录。`);
  }
  function exportJudgeEvidenceBackup() {
    if (!synchronizeReset()) return;
    const backup = storage.get(JUDGE_EVIDENCE_BACKUP_KEY, null);
    if (!backup || backup.schemaVersion !== 1 || !Array.isArray(backup.records)) return tell('没有判断题答案核验前的备份。');
    download(JSON.stringify(backup, null, 2), exportFilename('判断题答案核验前原始备份', backup.records.length, 'json'), 'application/json;charset=utf-8');
    tell(`已导出判断题答案核验前的 ${backup.records.length} 条原始记录。`);
  }
  async function parseImportFile(file) {
    if (file.size > 20 * 1024 * 1024) throw new Error('文件超过 20 MB，请拆分后导入');
    const text = (await file.text()).replace(/^\uFEFF/, '');
    let incoming;
    if (/\.json$/i.test(file.name) || /^[\s]*[\[{]/.test(text)) {
      const payload = JSON.parse(text);
      if (!Array.isArray(payload) && payload?.schemaVersion !== 1) throw new Error('不支持这个 JSON 备份版本');
      const source = Array.isArray(payload) ? payload : payload.records;
      if (!Array.isArray(source) || source.length > 50000) throw new Error('JSON 应包含不超过 50000 道题的 records 数组');
      incoming = source.map(record => {
        if (!record || typeof record !== 'object' || typeof record.stem !== 'string' || !record.stem.trim()) throw new Error('JSON 题目必须包含非空 stem 题干');
        if (!['single', 'multiple', 'judge', 'unknown'].includes(record.type)) throw new Error('JSON 中存在不支持的题型');
        if (record.answerStatus && !['confirmed', 'missing', 'conflict'].includes(record.answerStatus)) throw new Error('JSON 中存在不支持的答案状态');
        return QBCore.normalizeRecord(record);
      });
    } else incoming = QBCore.fromCSV(text);
    if (!incoming.length) throw new Error('文件中没有可导入的题目');
    const fallbackName = String(file.name).replace(/\.(csv|json)$/i, '').trim() || '导入题库';
    return incoming.map(record => QBCore.normalizeRecord({ ...record, bankName: !record.bankName || record.bankName === '未命名题库' ? fallbackName : record.bankName }));
  }
  async function importFiles(files) {
    if (!files.length) return;
    if (!synchronizeReset()) throw new Error('题库已重置，请重新选择导入文件');
    const importGeneration = libraryGeneration;
    if (loadError) throw new Error('现有本地题库异常，为保留原数据已停止写入。请先从油猴存储备份原数据');
    if (files.reduce((sum, file) => sum + file.size, 0) > 50 * 1024 * 1024) throw new Error('本次文件合计超过 50 MB，请分批导入');
    const incoming = [];
    // Parse every file before changing the library. A bad file cancels this batch.
    for (const file of files) {
      try { incoming.push(...await parseImportFile(file)); }
      catch (error) { throw new Error(`「${file.name}」：${error.message}`); }
      if (!synchronizeReset() || importGeneration !== libraryGeneration) throw new Error('题库已重置，本次导入已取消，请重新选择文件');
      if (incoming.length > 50000) throw new Error('本次导入超过 50000 条记录，请分批导入');
    }
    const before = records.length;
    const expanded = QBCore.upsert(records, repairAnswerConflicts(repairJudgeEvidence(removeBackedUpImagePredecessors(incoming, records)).records).records);
    const compacted = QBCore.compactRecords(expanded);
    if (compacted.removed > 0) ensureCleanupBackup(expanded);
    const merged = repairAnswerConflicts(repairJudgeEvidence(compacted.records).records).records;
    records = merged;
    recordsDirty = true;
    persistRecords();
    renderVisible();
    const bankCount = new Set(incoming.map(bankKey)).size;
    if (!storageError) tell(`已导入 ${files.length} 个文件、${bankCount} 个题库，共 ${incoming.length} 条记录，新增 ${Math.max(0, records.length - before)} 道题。各题库名称已分别保留。`);
  }

  const css = `
    :host{all:initial;position:fixed;right:12px;bottom:12px;z-index:2147483646;color:#555;font:12px/1.45 -apple-system,BlinkMacSystemFont,"Segoe UI","Microsoft YaHei",sans-serif;pointer-events:none;color-scheme:light}
    *,*:before,*:after{box-sizing:border-box}[hidden]{display:none!important}button,input,select{font:inherit}button{cursor:pointer}button:disabled{cursor:default;color:#aaa}button:focus-visible,input:focus-visible,select:focus-visible,summary:focus-visible{outline:1px solid #999;outline-offset:1px}
    #qb-panel{pointer-events:auto;width:300px;max-width:calc(100vw - 24px);max-height:min(440px,calc(100dvh - 24px));display:flex;flex-direction:column;border:1px solid #e7e7e7;border-radius:5px;background:#fff;box-shadow:0 1px 5px #00000009;overflow:hidden}
    .header{background:#fff;color:#555;padding:6px 9px;display:flex;align-items:center;justify-content:space-between;gap:6px;flex-shrink:0;border-bottom:1px solid #eee}.brand{font-size:12px;font-weight:500}.subtitle{display:none}.tools{display:flex;gap:5px}.tools button{border:0;color:#888;background:#fff;padding:2px 4px;font-size:10px;white-space:nowrap}.tools button:hover{color:#444;background:#f7f7f7}
    .body{overflow:auto;overscroll-behavior:contain;min-height:0;scrollbar-width:thin;scrollbar-color:#ddd #fff}.collapsed .body{display:none}.context{padding:6px 9px;background:#fff;border-bottom:1px solid #eee}.context strong{display:block;color:#555;font-size:11px;font-weight:400;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.context-count{font-size:10px;color:#999;margin-top:2px;line-height:1.35}
    .tabs{display:flex;padding:0 6px;background:#fff;border-bottom:1px solid #eee}.tabs button{flex:1;padding:6px 2px;background:#fff;border:0;border-bottom:1px solid transparent;color:#999;font-size:11px;white-space:nowrap}.tabs button.active{border-bottom-color:#888;color:#555}.view{padding:8px}
    .search-label{display:flex;justify-content:space-between;align-items:center;font-size:10px;color:#888;margin-bottom:5px}.text-button{border:0;background:#fff;color:#999;font-size:10px;padding:1px 3px}.text-button:hover{color:#555}.search-wrap{display:flex;gap:5px}.search-wrap input{width:100%;min-width:0;border:1px solid #ddd;border-radius:3px;padding:5px 6px;background:#fff;color:#555;font-size:11px}.btn{border:1px solid #ddd;border-radius:3px;padding:5px 8px;background:#fff;color:#666;font-size:11px;white-space:nowrap}.btn.primary{background:#fff;border-color:#ccc;color:#555}.btn:hover,.btn.primary:hover{background:#f7f7f7}.btn.small{padding:3px 6px;font-size:10px}
    .search-filters{display:grid;grid-template-columns:minmax(0,1.5fr) minmax(0,1fr);gap:5px;margin-top:6px}.search-filters label{min-width:0;color:#999;font-size:10px}.search-filters select{display:block;width:100%;min-width:0;border:1px solid #e2e2e2;background:#fff;padding:3px 2px;margin-top:2px;border-radius:3px;color:#777;font-size:10px}.hint{font-size:10px;color:#999;margin:5px 0 8px;line-height:1.4}
    .empty{padding:14px 8px;text-align:center;color:#999;border:1px dashed #e8e8e8;border-radius:3px;background:#fff}.empty strong{color:#888;font-size:12px;font-weight:400}.empty p{font-size:10px;line-height:1.6;margin:5px 0 0}.result{border:1px solid #eee;border-radius:3px;background:#fff;padding:8px;margin-bottom:6px}.meta{display:flex;align-items:center;justify-content:space-between;gap:5px;font-size:10px;color:#999}.badge{padding:0 3px;border:1px solid #e4e4e4;border-radius:2px;background:#fff;color:#888}.badge.confirmed,.badge.missing,.badge.conflict{background:#fff;color:#777}.badge.conflict{font-weight:600}.stem{font-size:11px;line-height:1.65;margin:6px 0;white-space:pre-wrap;overflow-wrap:anywhere}.answer,.answer.pending{border-radius:2px;background:#fff;border-left:2px solid #ddd;padding:3px 7px;display:flex;flex-direction:column;gap:2px;overflow-wrap:anywhere}.answer-label{font-size:10px;color:#999}.answer strong{color:#555;font-size:13px;line-height:1.5;white-space:pre-wrap}.answer.pending strong{color:#777;font-size:11px}.mapping{font-size:10px;color:#999}.source{font-size:9px;color:#aaa;margin-top:6px;overflow-wrap:anywhere}.explanation{margin-top:5px;color:#888;font-size:10px}.explanation summary{cursor:pointer}.explanation p{white-space:pre-wrap;overflow-wrap:anywhere}
    .section{padding:8px;border:1px solid #eee;background:#fff;border-radius:3px;margin-bottom:7px}.section h3{font-size:11px;font-weight:500;margin:0 0 5px;color:#555}.section p{font-size:10px;color:#999;margin:4px 0;line-height:1.55;overflow-wrap:anywhere}.row{display:flex;align-items:center;gap:5px;flex-wrap:wrap}.row.spread{justify-content:space-between}.scope{display:block;font-size:10px;color:#999;margin-bottom:5px}.scope select{margin-top:3px;width:100%;padding:4px 3px;border:1px solid #ddd;border-radius:3px;background:#fff;color:#666;font-size:11px}.export-name{font-size:10px!important;color:#777!important;font-weight:400;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;margin:3px 0 5px!important}.stats{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:3px;margin-bottom:6px}.stat{background:#fff;border:0;border-radius:0;padding:3px 0;text-align:center}.stat strong{display:block;font-size:16px;color:#666;font-weight:400}.stat span{font-size:9px;color:#aaa}.filename{font-size:9px!important;word-break:break-all;color:#aaa!important;line-height:1.4!important}.state,.state.paused{font-size:9px;color:#999;background:#fff;border-radius:2px;border:1px solid #eee;padding:0 3px}#qb-current-title{font-size:10px;color:#888;margin:5px 0;max-height:31px;overflow:auto;white-space:pre-wrap}.muted-bank{display:none}.bank-list{max-height:75px;overflow:auto;margin-top:5px}.bank-row{display:flex;align-items:flex-start;justify-content:space-between;gap:6px;border-top:1px solid #f1f1f1;padding:4px 0;font-size:10px;color:#999}.bank-row span{overflow-wrap:anywhere}.bank-row strong{flex-shrink:0;color:#888;font-weight:400}
    .check{display:flex;gap:6px;align-items:flex-start;margin:7px 0;color:#666;font-size:11px}.check input{accent-color:#888;margin-top:2px}.check small{display:block;font-size:10px;color:#aaa;margin-top:2px}.kbd{background:#fff;border:1px solid #eee;border-radius:2px;padding:1px 4px;font-family:monospace;font-size:10px;color:#777}.footer{padding:5px 9px;font-size:9px;color:#aaa;background:#fff;overflow-wrap:anywhere;line-height:1.4;border-top:1px solid #eee;max-height:38px;overflow:auto}#qb-status[data-error="true"]{color:#777;font-weight:500}.footline{display:none}#qb-launcher{display:none!important}
    @media(max-width:340px){:host{right:8px;bottom:8px}#qb-panel{max-width:calc(100vw - 16px);max-height:min(440px,calc(100dvh - 16px))}}
  `;

  function mount() {
    if (mounted || document.getElementById('huayi-qb-root')) return;
    activateKnownPage();
    root = node('div'); root.id = 'huayi-qb-root';
    shadow = root.attachShadow({ mode: 'open' });
    const style = node('style'); style.textContent = css;
    shadow.append(style);
    const ui = node('div');
    ui.innerHTML = `
      <section id="qb-panel" role="region" aria-label="华谊题库助手">
        <header class="header"><div><div class="brand">题库助手</div><div class="subtitle">HUAYI · 本地练习资料</div></div><div class="tools"><button type="button" data-action="collapse" title="收起或展开内容" aria-expanded="true">收起</button><button type="button" data-action="hide" title="隐藏面板，Alt + Shift + Q 恢复">隐藏</button></div></header>
        <div class="body">
          <div class="context"><strong id="qb-context-name">正在识别题库…</strong><div class="context-count"><span id="qb-context-count"></span><span id="qb-page-total"></span></div></div>
          <nav class="tabs" role="tablist" aria-label="助手功能"><button type="button" data-tab="search" role="tab" aria-controls="qb-view-search">文字搜索</button><button type="button" data-tab="library" role="tab" aria-controls="qb-view-library">题库 / 导出</button><button type="button" data-tab="auto" role="tab" aria-controls="qb-view-auto">自动答题</button><button type="button" data-tab="settings" role="tab" aria-controls="qb-view-settings">设置</button></nav>
          <div class="view" id="qb-view-search" data-view="search" role="tabpanel"><div class="search-label"><label for="qb-search">输入或粘贴文字查答案</label><button type="button" class="text-button" data-action="clear-search">清空</button></div><div class="search-wrap"><input id="qb-search" type="search" maxlength="4000" placeholder="题干、选项或答案关键词…" aria-label="文字搜索"><button type="button" class="btn primary" data-action="search">搜索</button></div><div class="search-filters"><label>搜索题库<select id="qb-search-scope" aria-label="搜索题库"><option value="__current__">当前题库</option><option value="">全部题库</option></select></label><label>搜索内容<select id="qb-search-field" aria-label="搜索内容"><option value="all">全部文字</option><option value="stem">仅题干</option><option value="options">仅选项</option><option value="answer">仅标准答案</option></select></label></div><p class="hint" id="qb-query-state"></p><div id="qb-results" aria-live="polite"></div></div>
          <div class="view" id="qb-view-library" data-view="library" role="tabpanel" hidden>
            <div class="section"><h3>统计与导出范围</h3><label class="scope">选择题库<select id="qb-scope" aria-label="题库范围"><option value="__current__">当前题库</option><option value="">全部题库</option></select></label><p class="export-name" id="qb-export-name"></p><div class="stats"><div class="stat"><strong id="qb-stat-total">0</strong><span>范围内题数</span></div><div class="stat"><strong id="qb-stat-confirmed">0</strong><span>答案确认</span></div><div class="stat"><strong id="qb-stat-missing">0</strong><span>待补答案</span></div><div class="stat"><strong id="qb-stat-conflicts">0</strong><span>答案冲突</span></div></div><div class="row"><button type="button" class="btn primary" data-action="export-csv">导出 CSV</button><button type="button" class="btn" data-action="export-json">备份 JSON</button></div><p class="filename" id="qb-export-preview"></p></div>
            <div class="section"><div class="row spread"><h3>当前练习</h3><span class="state" id="qb-capture-state">采集中</span></div><p id="qb-current-bank" class="muted-bank"></p><div id="qb-current-title"></div><div class="row"><button type="button" class="btn small primary" data-action="capture-current">采集当前题</button><button type="button" class="btn small" data-action="toggle-capture">暂停采集</button></div></div>
            <div class="section"><div class="row spread"><h3>已保存题库</h3><button type="button" class="btn small" data-action="import">导入多个题库</button></div><input id="qb-import-file" type="file" accept=".csv,.json,text/csv,application/json" multiple hidden><p id="qb-library-summary"></p><div class="bank-list" id="qb-bank-list"></div><button type="button" class="btn small" data-action="reset-library">重置全部题库</button></div>
          </div>
          <div class="view" id="qb-view-auto" data-view="auto" role="tabpanel" hidden>
            <div class="section"><h3>自动选择正确答案</h3><p>根据本地已确认答案核对题干、题型和完整选项，按当前顺序选择。没有答案、答案冲突或无法唯一匹配的题目会跳过。</p><button type="button" class="btn primary" data-action="auto-answer-current">答当前题</button><label class="check"><input id="qb-auto-enabled" type="checkbox"><span>连续自动选择<small>开启后随题目变化自动选择，仅本页有效；刷新或打开新页面后关闭。</small></span></label><p id="qb-auto-status" role="status"></p><p id="qb-auto-count"></p><p>选择后按页面流程检查、提交或换题；部分网站会自动保存作答。</p></div>
            <div class="section"><h3>补齐判断题标准答案</h3><p>会逐题进行正常练习作答并改变练习记录；以网站标准反馈保存。只限当前判断练习，刷新默认关闭。隐藏面板后仍会继续；需要停止时请点击“停止补齐”。</p><div class="row"><button type="button" class="btn primary" data-action="start-collector">补齐当前判断题库</button><button type="button" class="btn" data-action="stop-collector" disabled>停止补齐</button></div><p id="qb-collector-status" role="status">练习补齐默认关闭。</p><p id="qb-collector-count"></p></div>
            <div class="section"><h3>适配范围</h3><p>支持华谊练习页面，以及使用标准单选框／复选框和明确题干容器的网页。网页未识别时可继续使用文字搜索。</p></div>
          </div>
          <div class="view" id="qb-view-settings" data-view="settings" role="tabpanel" hidden>
            <div class="section"><h3>重置本地题库</h3><p>清空全部题库、答案、冲突及历史修复备份，同时暂停采集并关闭自动答题。重置前如需保留，请先导出 JSON；重置后重新导入可信题库。</p><button type="button" class="btn small" data-action="reset-library">重置全部题库</button></div>
            <div class="section"><h3>面板显示</h3><p>每次打开或刷新网页都默认完全隐藏，不显示悬浮按钮。</p><p>显示 / 隐藏快捷键：<kbd class="kbd">Shift + Alt + Q</kbd></p><p>面板隐藏时，划选文字仍可更新检索内容，面板保持隐藏。</p><button type="button" class="btn small" data-action="hide">立即隐藏</button></div>
            <div class="section"><h3>选择与复制</h3><label class="check"><input id="qb-copy-enabled" type="checkbox"><span>恢复题目区域的选择复制<small>换题后自动适配，关闭后恢复原有处理。</small></span></label></div>
            <div class="section"><h3>答案规则</h3><p>按标准答案内容保存，再对应当前页面的选项位置。没有标准答案就显示待补；不同答案会保留冲突。所有资料保存在当前浏览器，建议定期导出备份。</p></div>
            <div class="section"><h3>重复记录整理</h3><p>重复加载的题目按批次对应合并，保留原题库中的同文题和全部来源 ID。首次整理前会保留原始备份。</p><button type="button" class="btn small" data-action="export-dedup-backup">导出整理前备份</button></div>
            <div class="section"><h3>答案误报恢复</h3><p>只恢复旧版因多个正确选项文字相同产生、且全部冲突证据一致的误报。修复前记录独立备份，真实答案冲突继续保留。</p><button type="button" class="btn small" data-action="export-option-repair-backup">导出误报修复前备份</button></div>
            <div class="section"><h3>旧题内容补全</h3><p>新完整题库批次与页面题数一致、位置和文字答案均能唯一核对时，补全旧版遗漏的图片、乘号或正负号实体，并保留原始题目 ID 与独立备份。</p><button type="button" class="btn small" data-action="export-image-upgrade-backup">导出内容补全前备份</button></div>
            <div class="section"><h3>判断题答案核验</h3><p>缺少网页标准答案依据的旧判断题改为待补；重新取得标准答案后补全，核验前原值单独保留。</p><button type="button" class="btn small" data-action="export-judge-evidence-backup">导出判断题核验前备份</button></div>
          </div>
          <footer class="footer"><div class="footline"><span class="dot"></span><span>本地题库 · 标准答案优先</span></div><div id="qb-status" role="status"></div></footer>
        </div>
      </section><button type="button" id="qb-launcher" data-action="restore" title="显示题库助手 · Alt + Shift + Q" aria-label="显示题库助手" hidden>题库</button>`;
    shadow.append(...ui.childNodes);
    (document.body || document.documentElement).append(root);
    panel = shadow.getElementById('qb-panel'); launcher = shadow.getElementById('qb-launcher');
    resultBox = shadow.getElementById('qb-results'); statusBox = shadow.getElementById('qb-status');
    mounted = true;
    shadow.getElementById('qb-copy-enabled').checked = Boolean(config.copyEnabled);
    shadow.addEventListener('click', event => {
      const button = event.target.closest('button');
      if (!button) return;
      if (button.dataset.tab) return selectTab(button.dataset.tab);
      try {
        switch (button.dataset.action) {
          case 'hide': setMode('hidden'); break;
          case 'restore': setMode('open'); break;
          case 'collapse': setMode(config.mode === 'collapsed' ? 'open' : 'collapsed'); break;
          case 'search': runSearch(shadow.getElementById('qb-search').value); break;
          case 'clear-search': clearTimeout(searchTimer); runSearch(''); shadow.getElementById('qb-search').focus(); break;
          case 'auto-answer-current': stopCollector('已切换为答当前题，练习补齐已停止。'); Promise.resolve(autoAnswer.answerCurrent()).catch(error => tell(`自动选择失败：${error.message}`, true)); break;
          case 'start-collector': startCollector(); break;
          case 'stop-collector': stopCollector('已手动停止练习补齐。'); renderAuto(); break;
          case 'capture-current': {
            const captured = adapter.captureCurrent();
            renderCurrent();
            if (captured) tell(`已检查「${captured.bankName || '当前题库'}」的当前题目；尚未取得的标准答案会标为待补。`);
            break;
          }
          case 'toggle-capture':
            config.collecting = !config.collecting;
            if (!config.collecting) stopCollector('题库采集已暂停，练习补齐已停止。');
            config.collecting ? adapter.start() : adapter.stop();
            adapter.setCopyEnabled(Boolean(config.copyEnabled));
            persistConfig(); renderStats();
            tell(config.collecting ? '已继续采集。此前未观察到的响应，可在重新进入练习后采集。' : '已暂停自动采集，已保存的题库仍可检索和导出。');
            break;
          case 'export-csv': exportData('csv'); break;
          case 'export-json': exportData('json'); break;
          case 'export-dedup-backup': exportCleanupBackup(); break;
          case 'export-option-repair-backup': exportOptionRepairBackup(); break;
          case 'export-image-upgrade-backup': exportImageUpgradeBackup(); break;
          case 'export-judge-evidence-backup': exportJudgeEvidenceBackup(); break;
          case 'reset-library': resetLibrary(); break;
          case 'import': shadow.getElementById('qb-import-file').click(); break;
        }
      } catch (error) { tell(`操作失败：${error.message}`, true); }
    });
    shadow.getElementById('qb-search').addEventListener('input', event => {
      clearTimeout(searchTimer); const value = event.target.value;
      searchTimer = setTimeout(() => runSearch(value), 180);
    });
    shadow.getElementById('qb-search').addEventListener('keydown', event => {
      if (event.key === 'Enter') { clearTimeout(searchTimer); runSearch(event.target.value); }
    });
    shadow.getElementById('qb-scope').addEventListener('change', event => { scope = event.target.value; renderStats(); });
    shadow.getElementById('qb-search-scope').addEventListener('change', event => { searchScope = event.target.value; renderResults(); });
    shadow.getElementById('qb-search-field').addEventListener('change', event => { searchField = event.target.value; renderResults(); });
    shadow.getElementById('qb-auto-enabled').addEventListener('change', event => {
      const enabled = event.target.checked;
      if (enabled) stopCollector('已启用连续自动选择，练习补齐已停止。');
      autoAnswer.setEnabled(enabled); renderAuto();
    });
    shadow.getElementById('qb-copy-enabled').addEventListener('change', event => { config.copyEnabled = event.target.checked; adapter.setCopyEnabled(config.copyEnabled); persistConfig(); });
    shadow.getElementById('qb-import-file').addEventListener('change', async event => {
      const input = event.currentTarget;
      if (importing) return;
      const files = Array.from(input.files || []);
      const attempt = ++importAttempt;
      importing = true;
      stopCollector('开始导入题库，练习补齐已停止。');
      const button = shadow.querySelector('[data-action="import"]');
      button.disabled = true;
      try { await importFiles(files); }
      catch (error) { if (attempt === importAttempt) tell(`导入失败，题库未替换：${error.message}`, true); }
      finally { if (attempt === importAttempt) { input.value = ''; importing = false; button.disabled = false; } }
    });
    if (cleanupNotice) status = cleanupNotice;
    refreshScope(); renderStats(); renderCurrent(); renderResults(); renderAuto(); renderStatus(); selectTab(config.tab); renderMode();
    // Navigation/collection is driven by the adapter. A hidden panel has no
    // polling/render loop; only an open, foreground panel refreshes its header.
    setInterval(() => { if (config.mode === 'open' && !document.hidden) renderCurrent(); }, 2000);
  }

  document.addEventListener('mouseup', event => {
    if (event.composedPath().includes(root)) return;
    const active = document.activeElement;
    if (active && (active.matches('input,textarea,[contenteditable="true"]'))) return;
    clearTimeout(searchTimer);
    searchTimer = setTimeout(() => {
      const selected = window.getSelection()?.toString().trim();
      if (selected && selected.length >= 2 && selected.length <= 4000) {
        runSearch(selected);
        if (shadow && config.tab !== 'search') selectTab('search');
      }
    }, 120);
  });
  window.addEventListener('keydown', event => {
    if (isToggleShortcut(event)) {
      event.preventDefault(); setMode(config.mode === 'hidden' ? 'open' : 'hidden');
    }
  }, true);
  window.addEventListener('message', event => {
    if (event.data?.type !== FRAME_SHORTCUT || !event.source || event.source === window) return;
    try {
      if (event.source.top === window || event.source.top === pageWindow) setMode(config.mode === 'hidden' ? 'open' : 'hidden');
    } catch (_) { /* Ignore messages from unrelated or inaccessible windows. */ }
  });
  window.addEventListener('pagehide', () => { stopCollector('页面已离开，练习补齐已停止。'); autoAnswer.setEnabled(false); persistRecords(); });
  window.addEventListener('pageshow', event => {
    synchronizeReset();
    if (event.persisted) { stopCollector('页面已恢复，练习补齐保持关闭。'); autoAnswer.setEnabled(false); config.mode = 'hidden'; renderMode(); }
  });
  window.addEventListener('focus', synchronizeReset);
  document.addEventListener('visibilitychange', () => { if (!document.hidden) synchronizeReset(); });
  if (typeof GM_registerMenuCommand === 'function') {
    GM_registerMenuCommand('显示题库助手（Alt+Shift+Q）', () => setMode('open'));
    GM_registerMenuCommand('隐藏题库助手', () => setMode('hidden'));
    GM_registerMenuCommand('重置全部本地题库', resetLibrary);
    GM_registerMenuCommand('导出整理前原始题库备份', exportCleanupBackup);
    GM_registerMenuCommand('导出答案误报修复前原始备份', exportOptionRepairBackup);
    GM_registerMenuCommand('导出内容补全前原始备份', exportImageUpgradeBackup);
    GM_registerMenuCommand('导出判断题答案核验前原始备份', exportJudgeEvidenceBackup);
  }
  function mergeRemoteRecords(value) {
    if (!Array.isArray(value)) return;
    try {
      const valueText = JSON.stringify(value);
      if (valueText === storedRecordsText) return;
      const retained = removeBackedUpImagePredecessors(value, records);
      const judgeRepair = repairJudgeEvidence(retained);
      const incoming = repairAnswerConflicts(judgeRepair.records);
      records = repairAnswerConflicts(repairJudgeEvidence(QBCore.compactRecords(QBCore.upsert(records, incoming.records)).records).records).records;
      storedRecordsText = valueText;
      if (judgeRepair.changed.length || incoming.repaired.length || retained.length < value.length) { recordsDirty = true; schedulePersist(); }
      renderVisible();
    }
    catch (error) { tell(`跨标签题库未合并：${error.message}。当前内存记录仍保留。`, true); }
  }
  function watchRecords() {
    if (recordsListener !== null && typeof GM_removeValueChangeListener === 'function') GM_removeValueChangeListener(recordsListener);
    if (typeof GM_addValueChangeListener !== 'function') return;
    const generation = libraryGeneration;
    recordsListener = GM_addValueChangeListener(scopedKey(RECORDS_KEY, generation), (_key, _old, value, remote) => {
      if (remote && synchronizeReset() && generation === libraryGeneration) mergeRemoteRecords(value);
    });
  }
  if (typeof GM_addValueChangeListener === 'function') GM_addValueChangeListener(RESET_KEY, (_key, _old, _value, remote) => {
    if (remote) synchronizeReset();
  });
  watchRecords();
  // The fallback uses origin-local storage; GM storage remains shared across
  // supported sites. No polling is needed for either reset notification path.
  window.addEventListener('storage', event => {
    if (event.key === RESET_KEY) synchronizeReset();
    else if (event.key === scopedKey(RECORDS_KEY, libraryGeneration) && synchronizeReset()) {
      try { mergeRemoteRecords(event.newValue === null ? [] : JSON.parse(event.newValue)); }
      catch (error) { tell(`跨标签题库读取失败：${error.message}`, true); }
    }
  });
  if (config.collecting) adapter.start();
  adapter.setCopyEnabled(Boolean(config.copyEnabled));
  if (recordsDirty && !loadError) schedulePersist();
  if (document.readyState === 'loading') document.addEventListener('DOMContentLoaded', mount, { once: true });
  else mount();
})();

})();