/* 独立题库助手面板：页面正文与面板样式互不影响。 */
(function (global) {
  'use strict';

  const ROLES = ['主操', '班长', '副操'];
  const PAGE_SIZE = 20;
  const TYPE_NAMES = { single: '单选', multiple: '多选', judgment: '判断', unknown: '未知' };

  function plain(value) { return String(value == null ? '' : value); }
  function normalized(value) { return plain(value).replace(/\s+/g, ' ').trim(); }
  function el(doc, tag, className, value) {
    const node = doc.createElement(tag);
    if (className) node.className = className;
    if (value != null) node.textContent = value;
    return node;
  }

  function create(callbacks) {
    callbacks = callbacks || {};
    const doc = global.document;
    const state = {
      autoAnswer: false, allowCopy: true, role: '', course: '', courses: [],
      bankTotal: 0, roleCounts: {}, storageMode: 'userscript', pageStatus: '等待识别练习页面',
      canAnswer: false, canExport: false, metrics: {}, exportEnabled: false, expanded: false, loading: false
    };
    let destroyed = false;
    let selectionText = '';
    let currentOffset = 0;
    let resultTotal = 0;
    const host = doc.createElement('div');
    host.id = 'yian-question-assistant';
    host.setAttribute('data-yian-assistant', '');
    host.style.cssText = 'all:initial!important;position:fixed!important;right:16px!important;bottom:16px!important;z-index:2147483646!important;display:block!important;max-width:calc(100vw - 24px)!important;font:13px/1.5 system-ui,"Microsoft YaHei",sans-serif!important;color:#17253d!important;';
    const root = host.attachShadow({ mode: 'open' });
    const style = doc.createElement('style');
    style.textContent = `
      :host{font-family:system-ui,-apple-system,"Microsoft YaHei",sans-serif;color:#17253d;font-size:13px;line-height:1.5;color-scheme:light;--accent:#225aca;--muted:#65728a;--line:#e4e9f1;--surface:#f5f7fb}
      *,*::before,*::after{box-sizing:border-box}button,input,select{font:inherit}button,input,select,label{-webkit-user-select:none;user-select:none}button{cursor:pointer}button:disabled,input:disabled,select:disabled{cursor:not-allowed;opacity:.5}button:focus-visible,input:focus-visible,select:focus-visible{outline:3px solid #b8d1ff;outline-offset:2px}button{border:1px solid var(--line);background:white;color:#273953;border-radius:7px;padding:6px 10px}button:hover:enabled{background:#f2f6ff;border-color:#b6caf1}input[type=text],select{width:100%;min-width:0;border:1px solid #cfd8e7;border-radius:7px;background:#fff;color:#17253d;padding:8px}select{padding:6px 8px}input[type=checkbox],input[type=radio]{accent-color:var(--accent)}
      .panel{width:354px;max-width:calc(100vw - 24px);background:white;border:1px solid #dce3ee;border-radius:13px;box-shadow:0 8px 36px #14264528;overflow:hidden}.header{display:flex;align-items:center;justify-content:space-between;padding:12px 14px;background:#172a49;color:white}.brand{font-size:15px;font-weight:700;letter-spacing:.2px}.toggle{border:0;background:#ffffff17;color:white;padding:3px 9px;border-radius:5px;min-width:30px}.toggle:hover:enabled{background:#ffffff2c;color:white;border-color:transparent}.body{padding:13px;max-height:calc(100vh - 102px);max-height:calc(100dvh - 102px);overflow:auto;overscroll-behavior:contain}.body[hidden]{display:none}.panel.collapsed{width:auto;min-width:140px}.collapsed .header{padding:10px 12px;gap:16px}.switches{display:grid;gap:9px;padding-bottom:12px;border-bottom:1px solid var(--line)}.switch-row{display:flex;align-items:center;justify-content:space-between;position:relative;gap:12px;cursor:pointer;font-weight:600}.switch{appearance:none;-webkit-appearance:none;width:35px;height:21px;margin:0;border:0!important;border-radius:20px;background:#b7c0ce;position:relative;transition:background .15s}.switch::after{content:"";position:absolute;width:15px;height:15px;top:3px;left:3px;border-radius:50%;background:white;box-shadow:0 1px 3px #0002;transition:transform .15s}.switch:checked{background:var(--accent)}.switch:checked::after{transform:translateX(14px)}.hint{font-size:12px;color:var(--muted);margin:6px 0 0;overflow-wrap:anywhere}.section{padding-top:12px}.section-title{font-size:13px;font-weight:700;margin:0 0 7px}.import-row{display:flex;align-items:center;gap:10px}.import-row button{white-space:nowrap}.bank-info{font-size:12px;color:var(--muted);overflow-wrap:anywhere}.storage{color:#97702e;margin:4px 0 0;font-size:11px}.roles{display:flex;gap:6px;flex-wrap:wrap}.role{display:flex;align-items:center;gap:4px;padding:6px 8px;border:1px solid var(--line);border-radius:7px;cursor:pointer;background:white;flex:1;justify-content:center;white-space:nowrap}.role.active{background:#edf3ff;border-color:#abc5fa;color:#194dab}.role input{margin:0}.role-count{font-size:10px;color:var(--muted)}.course-row{display:grid;grid-template-columns:36px 1fr;gap:7px;align-items:center;margin-top:8px}.search-row{display:flex;gap:6px;margin-top:9px}.search-row input{flex:1}.primary{background:var(--accent);border-color:var(--accent);color:white;white-space:nowrap}.primary:hover:enabled{background:#184baf;color:white;border-color:#184baf}.selection-search{margin-top:7px;font-size:12px;width:100%}.notice{padding:8px 9px;border-radius:7px;margin:10px 0 0;font-size:12px;overflow-wrap:anywhere;background:#edf3ff;color:#254e8b}.notice.warning{background:#fff5df;color:#8a5d11}.notice.error{background:#fff0ed;color:#a23a2c}.notice.success{background:#eaf7f0;color:#1e754c}.notice[hidden]{display:none}.results-title{font-size:12px;color:var(--muted);margin:11px 0 7px}.empty{background:var(--surface);border-radius:8px;padding:13px 10px;color:var(--muted);font-size:12px}.result{border:1px solid var(--line);border-radius:9px;padding:10px;margin-bottom:9px;-webkit-user-select:text;user-select:text}.question{font-weight:600;line-height:1.6;overflow-wrap:anywhere;margin:0 0 7px;white-space:pre-wrap}.type{display:inline-block;font-size:10px;font-weight:500;color:#556984;background:#eff3f8;padding:1px 5px;border-radius:4px;margin-right:5px;vertical-align:1px}.answer{font-weight:600;color:#1b714a;background:#edf8f1;border-radius:5px;padding:6px 7px;overflow-wrap:anywhere}.options{padding:0;margin:7px 0;list-style:none;font-size:12px;display:grid;gap:4px}.option{padding:3px 6px;border-radius:4px;overflow-wrap:anywhere;white-space:pre-wrap}.option.correct{color:#196442;background:#edf8f1;font-weight:600}.sources{font-size:11px;color:var(--muted);white-space:pre-wrap;overflow-wrap:anywhere;margin-top:5px}.conflict{color:#9d6012;background:#fff5df;border-radius:5px;font-size:11px;padding:6px;margin:6px 0}.copy-result{margin-top:8px;font-size:11px}.pagination{display:flex;align-items:center;justify-content:space-between;gap:8px;font-size:11px;color:var(--muted);margin:5px 0 0}.pagination button{font-size:11px;padding:4px 8px}.page-section{border-top:1px solid var(--line);margin-top:13px;padding-top:11px}.page-status{font-size:12px;white-space:pre-wrap;overflow-wrap:anywhere;color:var(--muted)}.metrics{display:flex;flex-wrap:wrap;gap:4px 10px;font-size:11px;color:var(--muted);margin-top:6px}.unprocessed{font-size:11px;color:#8b621c;margin-top:7px}.unprocessed summary{cursor:pointer}.unprocessed-list{max-height:155px;overflow:auto;padding:7px;border-radius:6px;background:#fff7e8;margin-top:4px;display:grid;gap:5px;overflow-wrap:anywhere}.exports{display:flex;gap:6px;margin-top:9px}.exports button{flex:1;font-size:12px}.auto-export{display:flex;align-items:center;gap:5px;font-size:11px;color:var(--muted);margin-top:8px}.auto-export input{margin:0}.busy{color:#83692c}.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}@media(max-width:420px){.body{padding:11px}.panel{width:350px}.role{padding:6px 5px}}
    `;
    root.appendChild(style);
    const visibilityStyle = doc.createElement('style');
    visibilityStyle.textContent = '[hidden]{display:none!important}';
    root.appendChild(visibilityStyle);
    const panel = el(doc, 'section', 'panel collapsed');
    panel.setAttribute('aria-label', '谊安学助手 2.0');
    const header = el(doc, 'div', 'header');
    const brand = el(doc, 'span', 'brand', '题库助手');
    const expand = el(doc, 'button', 'toggle', '展开');
    expand.type = 'button';
    expand.setAttribute('aria-label', '展开题库助手');
    expand.setAttribute('aria-expanded', 'false');
    header.append(brand, expand);
    const body = el(doc, 'div', 'body');
    body.hidden = true;
    panel.append(header, body);
    root.appendChild(panel);

    function invoke(name) {
      if (destroyed || typeof callbacks[name] !== 'function') return;
      const args = Array.prototype.slice.call(arguments, 1);
      try {
        const result = callbacks[name].apply(null, args);
        if (result && typeof result.catch === 'function') result.catch(function (error) { setNotice(error && error.message || '操作失败，请重试。', 'error'); });
        return result;
      } catch (error) { setNotice(error && error.message || '操作失败，请重试。', 'error'); }
    }
    function setNotice(message, level) {
      notice.textContent = plain(message);
      notice.className = 'notice ' + (['warning', 'error', 'success'].includes(level) ? level : 'info');
      notice.hidden = !message;
    }
    function togglePanel() { state.expanded = !state.expanded; refresh(); }
    expand.addEventListener('click', togglePanel);
    brand.style.cursor = 'pointer';
    brand.addEventListener('click', togglePanel);

    const switches = el(doc, 'div', 'switches');
    function makeSwitch(labelText, callback, container) {
      const label = el(doc, 'label', 'switch-row');
      const text = el(doc, 'span', '', labelText);
      const input = el(doc, 'input', 'switch');
      input.type = 'checkbox';
      input.setAttribute('role', 'switch');
      input.setAttribute('aria-label', labelText);
      label.append(text, input);
      (container || switches).appendChild(label);
      input.addEventListener('change', callback);
      return { input: input, label: label };
    }
    const autoSwitch = makeSwitch('自动选择答案', function () { state.autoAnswer = autoSwitch.input.checked; invoke('onAutoChange', state.autoAnswer); refresh(); });
    const copySwitch = makeSwitch('允许复制文字', function () { state.allowCopy = copySwitch.input.checked; invoke('onCopyChange', state.allowCopy); refresh(); });
    const answerHint = el(doc, 'p', 'hint');
    switches.appendChild(answerHint);
    body.appendChild(switches);

    const bankSection = el(doc, 'div', 'section');
    const importRow = el(doc, 'div', 'import-row');
    const importButton = el(doc, 'button', '', '导入题库');
    importButton.type = 'button';
    const fileInput = el(doc, 'input');
    fileInput.type = 'file';
    fileInput.accept = '.zip,.csv,.json,application/zip,text/csv,application/json';
    fileInput.multiple = true;
    fileInput.hidden = true;
    const bankInfo = el(doc, 'span', 'bank-info');
    importRow.append(importButton, bankInfo, fileInput);
    const storageInfo = el(doc, 'p', 'storage');
    bankSection.append(importRow, storageInfo);
    body.appendChild(bankSection);
    importButton.addEventListener('click', function () { fileInput.click(); });
    fileInput.addEventListener('change', function () {
      const files = Array.from(fileInput.files || []);
      if (files.length) invoke('onImport', files);
      fileInput.value = '';
    });

    const searchSection = el(doc, 'div', 'section');
    searchSection.appendChild(el(doc, 'h2', 'section-title', '搜索题库'));
    const roles = el(doc, 'div', 'roles');
    roles.setAttribute('role', 'radiogroup');
    roles.setAttribute('aria-label', '选择岗位');
    const roleInputs = {};
    const roleLabels = {};
    const roleCounters = {};
    ROLES.forEach(function (role) {
      const label = el(doc, 'label', 'role');
      const input = el(doc, 'input');
      input.type = 'radio';
      input.name = 'yian-search-role';
      input.value = role;
      input.setAttribute('aria-label', role);
      const counter = el(doc, 'span', 'role-count');
      label.append(input, el(doc, 'span', '', role), counter);
      roles.appendChild(label);
      roleInputs[role] = input;
      roleLabels[role] = label;
      roleCounters[role] = counter;
      input.addEventListener('change', function () {
        if (!input.checked) return;
        const query = searchInput.value;
        state.role = role;
        state.course = '';
        currentOffset = 0;
        refresh();
        invoke('onRoleChange', role);
        if (normalized(query)) invoke('onSearch', query, { offset: 0 });
      });
    });
    searchSection.appendChild(roles);
    const courseRow = el(doc, 'label', 'course-row');
    const courseSelect = el(doc, 'select');
    courseSelect.setAttribute('aria-label', '选择课程');
    courseRow.append(el(doc, 'span', '', '课程'), courseSelect);
    courseSelect.addEventListener('change', function () {
      const query = searchInput.value;
      state.course = courseSelect.value;
      currentOffset = 0;
      invoke('onCourseChange', state.course);
      if (normalized(query)) invoke('onSearch', query, { offset: 0 });
    });
    searchSection.appendChild(courseRow);
    const searchRow = el(doc, 'div', 'search-row');
    const searchInput = el(doc, 'input');
    searchInput.type = 'text';
    searchInput.placeholder = '输入题干、关键词或选项文字…';
    searchInput.setAttribute('aria-label', '搜索题目');
    const searchButton = el(doc, 'button', 'primary', '搜索');
    searchButton.type = 'button';
    searchRow.append(searchInput, searchButton);
    searchSection.appendChild(searchRow);
    const selectionButton = el(doc, 'button', 'selection-search', '用选中文字搜索');
    selectionButton.type = 'button';
    searchSection.appendChild(selectionButton);
    const notice = el(doc, 'div', 'notice');
    notice.hidden = true;
    notice.setAttribute('role', 'status');
    notice.setAttribute('aria-live', 'polite');
    searchSection.appendChild(notice);
    const resultsTitle = el(doc, 'p', 'results-title');
    const results = el(doc, 'div', 'results');
    const pagination = el(doc, 'div', 'pagination');
    const previous = el(doc, 'button', '', '上一页');
    const pageLabel = el(doc, 'span');
    const next = el(doc, 'button', '', '下一页');
    previous.type = next.type = 'button';
    pagination.append(previous, pageLabel, next);
    pagination.hidden = true;
    searchSection.append(resultsTitle, results, pagination);
    body.appendChild(searchSection);

    function search(offset) {
      if (!state.role) { setNotice('请先选择岗位：主操、班长或副操。', 'warning'); return; }
      if (!normalized(searchInput.value)) { setNotice('请输入题干、关键词或选项文字。', 'warning'); searchInput.focus(); return; }
      currentOffset = Math.max(0, Number(offset) || 0);
      invoke('onSearch', searchInput.value, { offset: currentOffset });
    }
    searchButton.addEventListener('click', function () { search(0); });
    searchInput.addEventListener('keydown', function (event) { if (event.key === 'Enter' && !event.isComposing) { event.preventDefault(); search(0); } });
    previous.addEventListener('click', function () { search(Math.max(0, currentOffset - PAGE_SIZE)); });
    next.addEventListener('click', function () { search(currentOffset + PAGE_SIZE); });
    function rememberSelection() {
      const selected = global.getSelection && global.getSelection();
      if (!selected || !selected.anchorNode || !selected.focusNode) return;
      if (host.contains(selected.anchorNode) || host.contains(selected.focusNode) || root.contains(selected.anchorNode) || root.contains(selected.focusNode)) return;
      const text = selected.toString().trim();
      if (text) selectionText = text;
    }
    doc.addEventListener('selectionchange', rememberSelection);
    selectionButton.addEventListener('pointerdown', rememberSelection);
    selectionButton.addEventListener('click', function () {
      rememberSelection();
      if (!state.role) { setNotice('请先选择岗位：主操、班长或副操。', 'warning'); return; }
      if (!selectionText) { setNotice('请先在网页正文选中题目文字。', 'warning'); return; }
      searchInput.value = selectionText;
      currentOffset = 0;
      if (typeof callbacks.onSelectionSearch === 'function') invoke('onSelectionSearch', selectionText);
      else search(0);
    });

    const pageSection = el(doc, 'div', 'page-section');
    pageSection.appendChild(el(doc, 'h2', 'section-title', '当前练习'));
    const pageStatus = el(doc, 'div', 'page-status');
    const metrics = el(doc, 'div', 'metrics');
    const unprocessed = el(doc, 'details', 'unprocessed');
    const unprocessedSummary = el(doc, 'summary', '', '查看未处理题目');
    const unprocessedList = el(doc, 'div', 'unprocessed-list');
    unprocessed.append(unprocessedSummary, unprocessedList);
    unprocessed.hidden = true;
    pageSection.append(pageStatus, metrics, unprocessed);
    body.appendChild(pageSection);

    const exportSection = el(doc, 'section', 'page-section export-section');
    exportSection.setAttribute('aria-label', '题库导出设置');
    const exportSwitch = makeSwitch('导出题库', function () {
      state.exportEnabled = exportSwitch.input.checked;
      refresh();
      invoke('onExportEnabledChange', state.exportEnabled);
    }, exportSection);
    const exportContent = el(doc, 'div', 'export-content');
    exportContent.id = 'yian-export-content';
    exportContent.hidden = true;
    exportSwitch.input.setAttribute('aria-controls', exportContent.id);
    exportContent.appendChild(el(doc, 'p', 'hint', '开启后，题目和答案完整时自动导出 CSV；也可点击下方按钮重新导出。关闭后停止后续导出。'));
    const exportRow = el(doc, 'div', 'exports');
    const exportButtons = [];
    ['csv', 'json', 'txt'].forEach(function (format) {
      const button = el(doc, 'button', '', '导出 ' + format.toUpperCase());
      button.type = 'button';
      button.addEventListener('click', function () {
        if (state.exportEnabled && state.canExport) invoke('onExport', format);
      });
      exportRow.appendChild(button);
      exportButtons.push(button);
    });
    exportContent.appendChild(exportRow);
    exportSection.appendChild(exportContent);
    body.appendChild(exportSection);

    function autoUnavailableReason() {
      if (!state.role) return '请选择岗位后再开启自动选择。';
      if (!(Number(state.roleCounts && state.roleCounts[state.role]) > 0)) return '请导入包含' + state.role + '题目的题库。';
      if (!state.canAnswer) return state.pageStatus || '当前页面未识别到支持的练习题目。';
      return '';
    }
    autoSwitch.label.addEventListener('pointerdown', function () {
      const reason = autoUnavailableReason();
      if (!state.autoAnswer && reason) setNotice(reason, 'warning');
    });

    let courseSignature = '';
    function refresh() {
      if (destroyed) return;
      panel.classList.toggle('collapsed', !state.expanded);
      body.hidden = !state.expanded;
      brand.textContent = state.expanded ? '谊安学助手 2.0' : '题库助手';
      expand.textContent = state.expanded ? '收起' : '展开';
      expand.setAttribute('aria-label', state.expanded ? '收起题库助手' : '展开题库助手');
      expand.setAttribute('aria-expanded', String(Boolean(state.expanded)));
      const unavailable = autoUnavailableReason();
      autoSwitch.input.checked = Boolean(state.autoAnswer);
      autoSwitch.input.disabled = !state.autoAnswer && (Boolean(unavailable) || Boolean(state.loading));
      autoSwitch.label.title = unavailable;
      copySwitch.input.checked = Boolean(state.allowCopy);
      answerHint.textContent = unavailable || (state.autoAnswer ? '正在自动选择；关闭即可停止后续操作。' : '开启后选择已匹配的答案，交卷由你操作。');
      bankInfo.textContent = state.loading ? '正在读取题库…' : '已加载 ' + Number(state.bankTotal || 0).toLocaleString('zh-CN') + ' 条' + (state.role ? ' · ' + state.role + ' ' + Number(state.roleCounts && state.roleCounts[state.role] || 0).toLocaleString('zh-CN') + ' 条' : '');
      bankInfo.classList.toggle('busy', Boolean(state.loading));
      importButton.disabled = Boolean(state.loading);
      storageInfo.textContent = state.storageMode === 'origin' ? '此模式仅在当前网站保存题库和设置。' : '';
      storageInfo.hidden = !storageInfo.textContent;
      ROLES.forEach(function (role) {
        roleInputs[role].checked = state.role === role;
        roleLabels[role].classList.toggle('active', state.role === role);
        const count = Number(state.roleCounts && state.roleCounts[role] || 0);
        roleCounters[role].textContent = count ? '(' + count.toLocaleString('zh-CN') + ')' : '';
      });
      const availableCourses = (state.courses || []).map(function (course) {
        return typeof course === 'string' ? { value: course, label: course } : { value: plain(course.value == null ? (course.course || course.name) : course.value), label: plain(course.label || course.name || course.course || course.value) };
      });
      const signature = JSON.stringify(availableCourses);
      if (signature !== courseSignature) {
        courseSignature = signature;
        courseSelect.replaceChildren();
        const all = el(doc, 'option', '', '全部课程');
        all.value = '';
        courseSelect.appendChild(all);
        availableCourses.forEach(function (course) { const option = el(doc, 'option', '', course.label); option.value = course.value; courseSelect.appendChild(option); });
      }
      courseSelect.value = state.course || '';
      courseSelect.disabled = !state.role || Boolean(state.loading);
      searchButton.disabled = Boolean(state.loading);
      selectionButton.disabled = Boolean(state.loading);
      pageStatus.textContent = state.pageStatus || '等待识别练习页面';
      metrics.replaceChildren();
      const metricLabels = { selected: '已选择', pending: '待确认', missing: '未匹配', conflict: '冲突', locked: '已锁定', unsupported: '需人工核对', failed: '失败', skipped: '已跳过' };
      Object.keys(metricLabels).forEach(function (key) {
        if (state.metrics && state.metrics[key] != null) metrics.appendChild(el(doc, 'span', '', metricLabels[key] + ' ' + Number(state.metrics[key] || 0)));
      });
      const notProcessed = (state.metrics && state.metrics.details || []).filter(function (item) { return item.status !== 'selected'; });
      unprocessed.hidden = !notProcessed.length;
      unprocessedSummary.textContent = '查看未处理题目（' + notProcessed.length + '）';
      unprocessedList.replaceChildren();
      notProcessed.forEach(function (item) {
        unprocessedList.appendChild(el(doc, 'div', '', '第 ' + item.number + ' 题 · ' + (metricLabels[item.status] || '已跳过') + '：' + (item.reason || '请人工核对。')));
      });
      exportSwitch.input.checked = Boolean(state.exportEnabled);
      exportContent.hidden = !state.exportEnabled;
      exportButtons.forEach(function (button) { button.disabled = !state.exportEnabled || !state.canExport; });
      previous.disabled = currentOffset === 0 || Boolean(state.loading);
      next.disabled = currentOffset + PAGE_SIZE >= resultTotal || Boolean(state.loading);
    }

    function optionsOf(item) {
      if (Array.isArray(item.options)) return item.options.map(function (option, index) {
        return typeof option === 'string' ? { label: String.fromCharCode(65 + index), text: option } : { label: plain(option.label || option.key || String.fromCharCode(65 + index)), text: plain(option.text == null ? option.value : option.text), correct: option.correct };
      });
      return Object.keys(item.options || {}).map(function (label) { return { label: label, text: plain(item.options[label]) }; });
    }
    function sourcesOf(item) {
      const entries = Array.isArray(item.sources) && item.sources.length ? item.sources : [{ role: item.role || state.role, course: item.course || item.title || item.bankTitle || '', file: item.filename || '' }];
      return Array.from(new Set(entries.map(function (source) {
        if (typeof source === 'string') return source;
        return [source.role || item.role, source.course || source.title || source.bankTitle || source.name, source.filename || source.file].filter(Boolean).join(' / ');
      }).filter(Boolean)));
    }
    function answerInfo(item, options) {
      const answer = plain(item.answer == null ? item.correctAnswer : item.answer);
      const letters = plain(item.answerLabels || item.correctLabels || answer).replace(/[\s,，、;；.。]/g, '').toUpperCase();
      const texts = Array.isArray(item.answerTexts) ? item.answerTexts.map(normalized) : [];
      const correctOptions = options.filter(function (option) { return option.correct || /^[A-Z]+$/.test(letters) && letters.includes(option.label.toUpperCase()) || texts.includes(normalized(option.text)); });
      const description = item.answerText || correctOptions.map(function (option) { return option.label + ' — ' + (option.text || '[图片选项]'); }).join('；') || texts.join('；');
      return { answer: answer, description: plain(description), correctOptions: correctOptions };
    }
    async function copyText(value) {
      const legacyClipboard = typeof GM_setClipboard === 'function' ? GM_setClipboard : global.GM_setClipboard;
      const modernGM = typeof GM !== 'undefined' ? GM : global.GM;
      if (typeof legacyClipboard === 'function') { await legacyClipboard(value, 'text'); return; }
      if (modernGM && typeof modernGM.setClipboard === 'function') { await modernGM.setClipboard(value, 'text'); return; }
      if (global.navigator.clipboard && typeof global.navigator.clipboard.writeText === 'function') {
        try { await global.navigator.clipboard.writeText(value); return; } catch (_) { /* 再尝试浏览器复制命令。 */ }
      }
      const textarea = el(doc, 'textarea');
      textarea.value = value;
      textarea.style.cssText = 'position:fixed;left:0;top:0;opacity:0;width:1px;height:1px;';
      root.appendChild(textarea);
      textarea.focus();
      textarea.select();
      let copied = false;
      try { copied = doc.execCommand('copy'); } finally { textarea.remove(); }
      if (!copied) throw new Error('浏览器未允许复制，请选中结果文字手动复制。');
    }
    function renderSearch(result) {
      if (destroyed) return;
      result = result || {};
      const items = (result.items || []).slice(0, PAGE_SIZE);
      resultTotal = Number(result.total == null ? items.length : result.total) || 0;
      currentOffset = Math.max(0, Number(result.offset == null ? currentOffset : result.offset) || 0);
      resultsTitle.textContent = state.role ? '找到 ' + resultTotal.toLocaleString('zh-CN') + ' 道题 · 当前岗位：' + state.role : '先选择岗位，再搜索题目';
      results.replaceChildren();
      if (!items.length) results.appendChild(el(doc, 'div', 'empty', state.role ? '当前岗位未找到题目，可调整关键词、课程或切换岗位。' : '选择主操、班长或副操，导入题库后即可查找答案。'));
      items.forEach(function (item) {
        const card = el(doc, 'article', 'result');
        const title = el(doc, 'p', 'question');
        const type = TYPE_NAMES[item.type] || item.type || '题目';
        title.append(el(doc, 'span', 'type', type), doc.createTextNode(plain(item.question == null ? item.stem : item.question)));
        card.appendChild(title);
        const options = optionsOf(item);
        const info = answerInfo(item, options);
        card.appendChild(el(doc, 'div', 'answer', '正确答案：' + (info.answer || '见下方选项') + (info.description ? ' · ' + info.description : '')));
        const list = el(doc, 'ul', 'options');
        options.forEach(function (option) {
          const correct = info.correctOptions.includes(option);
          const row = el(doc, 'li', 'option' + (correct ? ' correct' : ''), option.label + '. ' + (option.text || '[图片选项]') + (correct ? ' ✓' : ''));
          list.appendChild(row);
        });
        card.appendChild(list);
        if (item.conflict || item.conflicts && item.conflicts.length || item.ambiguous) card.appendChild(el(doc, 'div', 'conflict', '此题存在不同答案，请核对课程来源；自动选择会跳过不明确的匹配。'));
        const sources = sourcesOf(item);
        card.appendChild(el(doc, 'div', 'sources', '来源：' + (sources.join('\n') || '未知')));
        const copyButton = el(doc, 'button', 'copy-result', '复制题目与答案');
        copyButton.type = 'button';
        copyButton.addEventListener('click', async function () {
          const content = ['[' + type + '] ' + plain(item.question == null ? item.stem : item.question)].concat(options.map(function (option) { return option.label + '. ' + (option.text || '[图片选项]'); }), ['正确答案：' + info.answer, info.description ? '对应选项：' + info.description : '', '来源：' + sources.join('；')]).filter(Boolean).join('\n');
          try { await copyText(content); setNotice('题目与答案已复制。', 'success'); } catch (error) { setNotice(error.message, 'error'); }
        });
        card.appendChild(copyButton);
        results.appendChild(card);
      });
      pagination.hidden = resultTotal <= PAGE_SIZE;
      pageLabel.textContent = resultTotal ? (currentOffset + 1) + '–' + Math.min(currentOffset + items.length, resultTotal) + ' / ' + resultTotal : '0 / 0';
      refresh();
    }

    function setState(partial) {
      if (destroyed) return;
      Object.assign(state, partial || {});
      refresh();
    }
    function destroy() {
      if (destroyed) return;
      destroyed = true;
      doc.removeEventListener('selectionchange', rememberSelection);
      host.remove();
    }
    (doc.body || doc.documentElement).appendChild(host);
    renderSearch({ items: [], total: 0 });
    refresh();
    return { setState: setState, renderSearch: renderSearch, setNotice: setNotice, destroy: destroy, host: host, root: root };
  }

  global.YianAssistantPanel = { create: create };
})(typeof window !== 'undefined' ? window : globalThis);