/* YianAnswerRunner: 只在已明确识别的练习或考试页面串行点击真实选项。 */
(function (root) {
  'use strict';

  const CHECKED = 'examtest_content_list_des_checked';
  const WAIT_STEP = 100;
  const WAIT_LIMIT = 1200;
  const CLICK_GAP = 150;
  const COUNT_KEYS = ['selected', 'pending', 'missing', 'conflict', 'locked', 'failed', 'unsupported'];
  const CONTEXT_KEYS = ['course', 'sourceUrl', 'routeKey', 'pageSignature', 'revision', 'exam', 'mode', 'topicKey'];

  function normalize(value) {
    // 仅中和排版空白和不可见分隔符；不折叠大小写、数字、单位或标点。
    return String(value == null ? '' : value).replace(/[\u200b-\u200d\u2060\uFEFF]/g, '').replace(/\s+/g, ' ').trim();
  }

  function questionSignature(question) {
    // 答案、checked class 和展开解析不属于题目身份，判分后它们会正常变化。
    return JSON.stringify([question.type, question.question, (question.questionImages || []), question.options.map(function (option) {
      return [option.label, option.text, option.images || []];
    })]);
  }

  function bankSignature(bank) {
    return JSON.stringify([bank.title, bank.expectedTotal, bank.questions.map(questionSignature)]);
  }

  function isLocked(box, selectors, context) {
    if (box.querySelector('.pc_examtest_content_form_disabled')) return true;
    if (box.closest('[disabled],[aria-disabled="true"]')) return true;
    if (Array.from(box.querySelectorAll(selectors.option)).some(function (node) { return Boolean(node.closest('[disabled],[aria-disabled="true"]')); })) return true;
    // 考试正常作答时没有查看答案控件，单选/判断也允许改选。
    // 已提交、到时或出现提交对话框由 getContext 将 exam 置 false，每一步都会复核。
    if (context && context.exam === true) return false;
    const component = box.closest('[app-exam-question],app-exam-question');
    const flags = [box, component].filter(Boolean);
    if (flags.some(function (element) {
      return element._showanswer === true || element.getAttribute('_showanswer') === 'true' || element.getAttribute('data-showanswer') === 'true';
    })) return true;
    if (!box.querySelector('.pc_examtest_content_question_showanswer')) return true;
    // 原页面已判分时 option 的直接父容器由 child1 变为 child2；隐藏参考答案不表示锁定。
    return Array.from(box.querySelectorAll(selectors.option)).some(function (node) {
      const parent = node.parentElement;
      return parent && parent.matches('.pc_examtest_content_list_child2,.pc_examtest_content_list_parent_child2,.parent_child2');
    });
  }

  function optionState(box, selectors, context) {
    const nodes = Array.from(box.querySelectorAll(selectors.option));
    return {
      nodes: nodes,
      selected: nodes.map(function (node) { return node.classList.contains(CHECKED); }),
      locked: isLocked(box, selectors, context)
    };
  }

  function sameSelection(actual, wanted) {
    return actual.length === wanted.length && actual.every(function (selected, index) { return selected === wanted[index]; });
  }

  function create(options) {
    options = options || {};
    if (typeof options.getContext !== 'function' || typeof options.match !== 'function') throw new TypeError('自动选择需要 getContext 和 match。');
    const doc = root.document;
    const core = root.QuestionBankCore;
    if (!doc || !core || !core.selectors || typeof core.extract !== 'function') throw new Error('自动选择需要 QuestionBankCore 和当前网页。');
    const selectors = core.selectors;
    let active = null;
    let scope = null;
    let records = new Map();
    let total = 0;
    let destroyed = false;
    let generation = 0;

    function notifyState(state, reason) {
      if (typeof options.onState === 'function') options.onState(state, reason || '');
    }

    function progress() {
      const counts = { selected: 0, pending: 0, missing: 0, conflict: 0, locked: 0, failed: 0, unsupported: 0, total: total };
      const details = [];
      records.forEach(function (record) {
        if (COUNT_KEYS.includes(record.status)) counts[record.status]++;
        if (record.pending) counts.pending++;
        details.push({
          number: record.number, question: record.question, course: record.course,
          pageCourse: record.pageCourse, sourceCourses: record.sourceCourses.slice(),
          status: record.status, reason: record.reason || '',
          correctTexts: record.correctTexts.slice(), correctLabels: record.correctLabels.slice(),
          currentLabels: record.currentLabels.slice(), currentTexts: record.currentTexts.slice(),
          currentAnswerText: record.currentAnswerText
        });
      });
      counts.details = details;
      return counts;
    }

    function notifyProgress() {
      const value = progress();
      if (typeof options.onProgress === 'function') options.onProgress(value);
      return value;
    }

    function setRecord(item, status, reason, pending) {
      const nodes = Array.from(item.box.querySelectorAll(selectors.option));
      const selected = item.question.options.filter(function (_, index) { return nodes[index] && nodes[index].classList.contains(CHECKED); });
      const sourceCourses = (item.sourceCourses || []).slice();
      records.set(item.key, {
        index: item.index, number: item.question.number, question: item.question.question,
        course: sourceCourses.length ? sourceCourses.join('、') : item.course,
        pageCourse: item.course, sourceCourses: sourceCourses,
        status: status, reason: reason || '', pending: Boolean(pending),
        correctTexts: (item.correctTexts || []).slice(), correctLabels: (item.correctLabels || []).slice(),
        currentLabels: selected.map(function (option) { return option.label; }),
        currentTexts: selected.map(function (option) { return option.text; }),
        currentAnswerText: selected.map(function (option) { return option.label + '. ' + option.text; }).join('；')
      });
      notifyProgress();
    }

    function captureContext(context) {
      const captured = { root: context.root, pageURL: String(root.location && root.location.href || '') };
      CONTEXT_KEYS.forEach(function (key) { captured[key] = context[key]; });
      return captured;
    }

    function sameContext(left, right) {
      return left && right && left.root === right.root && left.pageURL === right.pageURL && CONTEXT_KEYS.every(function (key) { return left[key] === right[key]; });
    }

    function initialReason(context) {
      if (!context || context.ready !== true) return '等待答题页面就绪。';
      if (context.local === true || root.location && root.location.protocol === 'file:') return '保存的静态网页可搜索和导出，不能记录自动选择。';
      if (context.practice !== true && context.exam !== true) return '当前页面未识别为可作答的练习或考试，自动选择已停止。';
      if (!context.root || !context.root.isConnected || context.root.ownerDocument !== doc) return '答题内容已切换，等待新页面。';
      return '';
    }

    function cancel(run) {
      if (!run || run.cancelled) return;
      run.cancelled = true;
      run.waiters.forEach(function (finish) { finish(false); });
      run.waiters.clear();
    }

    function endActive(state, reason) {
      const old = active;
      generation++;
      active = null;
      cancel(old);
      if (!destroyed) notifyState(state, reason);
      return progress();
    }

    function pause(reason) { return endActive('paused', reason || '已暂停自动选择。'); }

    function stop(reason) { return endActive('stopped', reason || '自动选择已关闭。'); }

    function wait(run, milliseconds) {
      if (run.cancelled || active !== run) return Promise.resolve(false);
      return new Promise(function (resolve) {
        let timer;
        let settled = false;
        const finish = function (ok) {
          if (settled) return;
          settled = true;
          root.clearTimeout(timer);
          run.waiters.delete(finish);
          resolve(ok && !run.cancelled && active === run);
        };
        run.waiters.add(finish);
        timer = root.setTimeout(function () { finish(true); }, milliseconds);
      });
    }

    function contextReason(run) {
      if (destroyed || run.cancelled || active !== run || run.id !== generation) return '自动选择已取消。';
      const context = options.getContext();
      const reason = initialReason(context);
      if (reason) return reason;
      if (!sameContext(run.context, captureContext(context))) return '页面、主题或题库已切换，已停止本轮自动选择。';
      return '';
    }

    function extractItems(context) {
      const boxes = Array.from(doc.querySelectorAll(selectors.question));
      const bank = core.extract(doc);
      if (bank.questions.length !== boxes.length) throw new Error('题目与选项尚未同步完成。');
      const items = boxes.map(function (box, index) {
        const question = bank.questions[index];
        const signature = questionSignature(question);
        return { box: box, index: index, question: question, course: context.course || '', signature: signature, key: index + '\u0000' + signature };
      }).filter(function (item) { return context.root === item.box || context.root.contains(item.box); });
      return { items: items, signature: bankSignature(bank) };
    }

    function readCurrent(run, item) {
      const reason = contextReason(run);
      if (reason) return { reason: reason, cancelled: true };
      if (!item.box.isConnected || !run.context.root.contains(item.box) && run.context.root !== item.box) return { reason: '题目节点已更新，已停止本轮自动选择。', cancelled: true };
      const boxes = Array.from(doc.querySelectorAll(selectors.question));
      if (boxes[item.index] !== item.box) return { reason: '题目顺序已变化，已停止本轮自动选择。', cancelled: true };
      const bank = core.extract(doc);
      // 父面板的 MutationObserver 尚未运行时，也直接阻断标题或其他题目的变化。
      if (bankSignature(bank) !== run.bankSignature) return { reason: '题目或课程已更新，已停止本轮自动选择。', cancelled: true };
      const current = bank.questions[item.index];
      if (!current || questionSignature(current) !== item.signature) return { reason: '题干或选项已变化，已停止本轮自动选择。', cancelled: true };
      const state = optionState(item.box, selectors, run.context);
      if (state.nodes.length !== current.options.length) return { reason: '选项尚未完整加载。' };
      return { question: current, state: state };
    }

    function clickable(node, item) {
      if (!node || !node.isConnected || !item.box.contains(node) || node.ownerDocument !== doc) return false;
      if (node.closest('[hidden],[inert]') || node.getAttribute('aria-disabled') === 'true' || node.hasAttribute('disabled')) return false;
      const style = root.getComputedStyle(node);
      return node.getClientRects().length > 0 && style.display !== 'none' && style.visibility !== 'hidden' && style.visibility !== 'collapse' && style.pointerEvents !== 'none';
    }

    function abortForChange(run, reason) {
      if (active === run && !run.cancelled) stop(reason);
      return false;
    }

    async function clickOption(run, item, optionIndex, wantedChecked) {
      const before = readCurrent(run, item);
      if (before.cancelled) return { cancelled: true, reason: before.reason };
      if (before.reason) return { reason: before.reason };
      if (before.state.locked) return { locked: true, reason: '该题已判分或锁定，不能修改。' };
      if (before.state.selected[optionIndex] === wantedChecked) return { ok: true };
      const node = before.state.nodes[optionIndex];
      if (!clickable(node, item)) return { reason: '选项不可点击，已跳过。' };
      // 最后一次即时检查，避免异步匹配期间已经换路由或岗位。
      const reason = contextReason(run);
      if (reason) return { cancelled: true, reason: reason };
      node.click();
      for (let elapsed = 0; elapsed <= WAIT_LIMIT; elapsed += WAIT_STEP) {
        const current = readCurrent(run, item);
        if (current.cancelled) return { cancelled: true, reason: current.reason };
        if (current.reason) return { reason: current.reason };
        if (current.state.selected[optionIndex] === wantedChecked) {
          if (!await wait(run, CLICK_GAP)) return { cancelled: true, reason: '自动选择已取消。' };
          const settled = readCurrent(run, item);
          if (settled.cancelled) return { cancelled: true, reason: settled.reason };
          if (settled.reason) return { reason: settled.reason };
          if (settled.state.selected[optionIndex] !== wantedChecked) return { reason: '网页未保留选项状态，已停止修改该题。' };
          return { ok: true };
        }
        if (current.state.locked) return { locked: true, reason: '选项点击后题目锁定，但未确认目标选项，已停止修改该题。' };
        if (elapsed < WAIT_LIMIT && !await wait(run, WAIT_STEP)) return { cancelled: true, reason: '自动选择已取消。' };
      }
      return { reason: '网页在限定时间内未更新选项状态，已跳过。' };
    }

    function resolveTargets(question, matched) {
      const labels = Array.isArray(matched.correctLabels) ? matched.correctLabels.map(normalize) : String(matched.correctLabels || '').split(/[\s,，、;；]+/).filter(Boolean);
      if (!labels.length || new Set(labels).size !== labels.length) return { reason: '正确选项为空或重复，已跳过。' };
      const actualLabels = question.options.map(function (option) { return normalize(option.label); });
      if (new Set(actualLabels).size !== actualLabels.length || labels.some(function (label) { return !actualLabels.includes(label); })) return { reason: '答案不能唯一对应网页选项，已跳过。' };
      if (question.type !== '多选' && labels.length !== 1) return { reason: '单选或判断题匹配到多个答案，已跳过。' };
      if (!Array.isArray(matched.correctTexts) || matched.correctTexts.length !== labels.length) return { reason: '题库缺少完整正确答案文字，不能仅凭答案字母自动选择。' };
      const expectedTexts = matched.correctTexts.map(normalize);
      if (expectedTexts.some(function (text) { return !text; }) || new Set(expectedTexts).size !== expectedTexts.length) return { reason: '正确答案文字为空或重复，无法唯一核验。' };
      const selected = question.options.filter(function (option) { return labels.includes(normalize(option.label)); });
      const actualTexts = selected.map(function (option) { return normalize(option.text); });
      if (JSON.stringify(expectedTexts.slice().sort()) !== JSON.stringify(actualTexts.slice().sort())) return { reason: '题库正确答案全文与网页选项不一致，已跳过。' };
      return {
        wanted: actualLabels.map(function (label) { return labels.includes(label); }),
        correctLabels: selected.map(function (option) { return option.label; }),
        // 原始题库文本按当页选项顺序存入证据，方便与 currentLabels 逐项核对。
        correctTexts: actualTexts.map(function (text) { return matched.correctTexts[expectedTexts.indexOf(text)]; })
      };
    }

    async function processQuestion(run, item) {
      run.currentBox = item.box;
      let current = readCurrent(run, item);
      if (current.cancelled) return abortForChange(run, current.reason);
      if (current.reason) { setRecord(item, 'failed', current.reason); return true; }
      const previous = records.get(item.key);
      if (previous && previous.status !== 'selected' && !previous.manualInvalid) return true;
      if (!item.box.closest('[app-exam-question],app-exam-question')) { setRecord(item, 'unsupported', '题目缺少已适配的答题组件，已跳过。'); return true; }
      if (!['单选', '多选', '判断'].includes(current.question.type)) { setRecord(item, 'unsupported', '暂不支持该题型自动选择。'); return true; }
      if (current.state.locked && !previous) { setRecord(item, 'locked', '该题已判分或锁定，保留原作答。'); return true; }
      const matched = await options.match(current.question, options.getContext());
      current = readCurrent(run, item);
      if (current.cancelled) return abortForChange(run, current.reason);
      if (current.reason) { setRecord(item, 'failed', current.reason); return true; }
      item.correctTexts = matched && Array.isArray(matched.correctTexts) ? matched.correctTexts.slice() : [];
      item.correctLabels = matched && Array.isArray(matched.correctLabels) ? matched.correctLabels.slice() : [];
      item.sourceCourses = Array.from(new Set((matched && Array.isArray(matched.records) ? matched.records : []).map(function (record) { return normalize(record.course); }).filter(Boolean)));
      if (current.state.locked && !previous) { setRecord(item, 'locked', '匹配期间该题已锁定，保留原作答。'); return true; }
      if (!matched || matched.status !== 'matched') {
        const status = matched && ['missing', 'conflict', 'unsupported'].includes(matched.status) ? matched.status : 'unsupported';
        setRecord(item, status, matched && matched.reason || '未获得可自动选择的唯一答案。');
        return true;
      }
      const target = resolveTargets(current.question, matched);
      if (target.reason) { setRecord(item, 'unsupported', target.reason); return true; }
      item.correctTexts = target.correctTexts;
      item.correctLabels = target.correctLabels;
      if (current.state.locked) {
        if (sameSelection(current.state.selected, target.wanted)) setRecord(item, 'selected', '已重新核验原作答与题库答案一致。');
        else setRecord(item, 'locked', '该题已锁定且当前作答不同于题库答案，保留原作答。');
        return true;
      }
      let changed = false;
      if (current.question.type === '多选') {
        // 每次按当前集合核对；先去掉错误选项，随后补选目标选项，不重复 toggle。
        const planned = [];
        target.wanted.forEach(function (wanted, index) { if (!wanted && current.state.selected[index]) planned.push({ index: index, checked: false }); });
        target.wanted.forEach(function (wanted, index) { if (wanted && !current.state.selected[index]) planned.push({ index: index, checked: true }); });
        for (const step of planned) {
          const result = await clickOption(run, item, step.index, step.checked);
          if (result.cancelled) return abortForChange(run, result.reason);
          if (!result.ok) { setRecord(item, result.locked && !changed ? 'locked' : 'failed', result.reason); return true; }
          changed = true;
        }
      } else {
        const wantedIndex = target.wanted.indexOf(true);
        if (!sameSelection(current.state.selected, target.wanted)) {
          if (current.state.selected[wantedIndex]) { setRecord(item, 'failed', '单选题有多个选中状态，已跳过。'); return true; }
          const result = await clickOption(run, item, wantedIndex, true);
          if (result.cancelled) return abortForChange(run, result.reason);
          if (!result.ok) { setRecord(item, result.locked ? 'locked' : 'failed', result.reason); return true; }
          changed = true;
        }
      }
      current = readCurrent(run, item);
      if (current.cancelled) return abortForChange(run, current.reason);
      if (current.reason) { setRecord(item, 'failed', current.reason); return true; }
      if (!sameSelection(current.state.selected, target.wanted)) { setRecord(item, 'failed', '网页当前选中集合与答案不一致，已停止修改该题。'); return true; }
      const pending = run.context.exam !== true && current.question.type === '多选' && !current.state.locked;
      setRecord(item, 'selected', pending ? '已选择，待网页确认。' : changed ? '已选择匹配答案。' : '当前已选中匹配答案。', pending);
      return true;
    }

    async function execute(run, items) {
      try {
        for (const item of items) {
          if (item !== items[0]) {
            const configured = typeof options.getInterval === 'function' ? Number(options.getInterval()) : 0;
            const gap = Number.isFinite(configured) ? Math.max(0, Math.min(120, configured)) * 1000 : 4000;
            if (gap && !await wait(run, gap)) return progress();
          }
          if (!await processQuestion(run, item)) return progress();
          if (run.cancelled || active !== run) return progress();
        }
        if (active === run && !run.cancelled) {
          active = null;
          notifyState('complete', '本页自动选择已完成。');
        }
      } catch (error) {
        if (active === run && !run.cancelled) {
          if (run.currentBox) {
            const item = items.find(function (candidate) { return candidate.box === run.currentBox; });
            if (item) setRecord(item, 'failed', error && error.message || '读取或点击选项失败。');
          }
          pause(error && error.message || '自动选择遇到错误，已暂停。');
        }
      } finally {
        cancel(run);
      }
      return progress();
    }

    function start() {
      if (destroyed) return Promise.resolve(progress());
      if (active && !active.cancelled) return active.promise;
      const context = options.getContext();
      const reason = initialReason(context);
      if (reason) { notifyState('idle', reason); return Promise.resolve(progress()); }
      const captured = captureContext(context);
      if (!sameContext(scope, captured)) { scope = captured; records = new Map(); total = 0; }
      let extracted;
      try { extracted = extractItems(context); }
      catch (error) { notifyState('idle', error.message || '等待题目加载。'); return Promise.resolve(progress()); }
      const items = extracted.items;
      total = items.length;
      const currentKeys = new Set(items.map(function (item) { return item.key; }));
      records.forEach(function (_, key) { if (!currentKeys.has(key)) records.delete(key); });
      notifyProgress();
      if (!items.length) { notifyState('idle', '当前没有可处理的答题题目。'); return Promise.resolve(progress()); }
      const run = { id: ++generation, context: captured, bankSignature: extracted.signature, cancelled: false, waiters: new Set(), currentBox: null, promise: null };
      active = run;
      // 先写入 promise，再通知或执行，使同步 UI 回调中的 start 也不会并发运行。
      run.promise = Promise.resolve().then(function () {
        if (active !== run || run.cancelled) return progress();
        notifyState('running', '正在选择统一题库中的精确匹配答案。');
        return execute(run, items);
      });
      return run.promise;
    }

    function manualClick(event) {
      if (!event.isTrusted || destroyed) return;
      const target = event.target && event.target.nodeType === 1 ? event.target : event.target && event.target.parentElement;
      if (!target) return;
      const run = active && !active.cancelled ? active : null;
      let currentScope = run && run.context;
      if (!currentScope && scope && records.size) {
        const context = options.getContext();
        if (!initialReason(context) && sameContext(scope, captureContext(context))) currentScope = scope;
      }
      if (!currentScope) return;
      const submit = target.closest('.pc_examtest_commit,button[type="submit"],input[type="submit"]');
      if (submit && currentScope.root.contains(submit)) {
        pause('检测到手动交卷，已暂停自动选择。');
        return;
      }
      const box = target.closest(selectors.question);
      if (!box || currentScope.root !== box && !currentScope.root.contains(box)) return;
      let invalidated = false;
      if (target.closest(selectors.option)) {
        const index = Array.from(doc.querySelectorAll(selectors.question)).indexOf(box);
        records.forEach(function (record) {
          if (record.index !== index || record.status !== 'selected') return;
          // 捕获阶段网页 onclick 还未执行，不能把此前的 checked 集合当成改选后的证据。
          record.status = 'unsupported';
          record.reason = '手动作答后需重新核对';
          record.pending = false;
          record.manualInvalid = true;
          record.correctTexts = [];
          record.correctLabels = [];
          record.currentLabels = [];
          record.currentTexts = [];
          record.currentAnswerText = '';
          invalidated = true;
        });
      }
      if (invalidated) notifyProgress();
      if (run || invalidated) pause('检测到手动作答，已暂停自动选择；可重新开启继续。');
    }

    doc.addEventListener('click', manualClick, true);

    function reset() {
      stop('自动选择状态已重置。');
      records = new Map();
      scope = null;
      total = 0;
      return notifyProgress();
    }

    function destroy() {
      if (destroyed) return;
      stop('自动选择已卸载。');
      destroyed = true;
      doc.removeEventListener('click', manualClick, true);
      records.clear();
    }

    return { start: start, stop: stop, reset: reset, destroy: destroy, get running() { return Boolean(active && !active.cancelled); } };
  }

  root.YianAnswerRunner = { version: '1.1.0', create: create };
})(typeof window !== 'undefined' ? window : globalThis);