import { createHash, randomUUID } from 'node:crypto';
import fs from 'node:fs/promises';
import path from 'node:path';
import readline from 'node:readline';
import process from 'node:process';
import { pathToFileURL } from 'node:url';
import { ACTION_KINDS, ActionInputError, validateAction, validateSelector } from './action-contract.mjs';
import { detectSession } from './session-detection.mjs';
import { beginSearchRequestPolicy, beginNoteOpenRequestPolicy, beginReadonlyRequestPolicy, beginNativeUiRequestPolicy, endPlatformRequestPolicy, evaluatePlatformRequest, NAVIGATION_UI_POLICY_VERSION } from './platform-policy.mjs';
import {NAVIGATION_UI_PROFILE,isNativeUiProfile,validNavigationPage,navigationPopupMatches,resolveExecutionProfile,executionMetadata,executionContractMatches,validNativePage,assertNativeUiAction,assertNativeUiResultLocation,nativeSearchKeyword,nativeReadRootsValid} from './execution-profile.mjs';

const HOME = path.resolve(process.env.ASSISTANT_LEARNING_HOME || '.runtime/learning');
const CHANNEL = process.env.ASSISTANT_BROWSER_CHANNEL || 'chromium';
const HEADLESS = process.env.ASSISTANT_BROWSER_HEADLESS === '1';
const TIMEOUT = 8_000;
const MAX_STEPS = 30;
const MAX_BLOCKED_REQUESTS = 12;
const sessions = new Map();
const contexts = new Set();
const accountOwners = new Map();
const closingAccounts = new Map();
let chromiumPromise;
let shuttingDown = false;
let shutdownPromise;

export class WorkerError extends Error {
  constructor(message, code = 'WORKER_ERROR') {
    super(message);
    this.code = code;
  }
}

const TIMING_PHASES=['validate','inspect_current','capture_before','resolve_target','execute','settle','request_guard','capture_after','failure_capture','batch_capture'];
function actionTrace(){
  const start=performance.now(),costs=Object.fromEntries(TIMING_PHASES.map(phase=>[phase,0]));
  const visited=new Set(['validate']);
  let phase='validate',last=start;
  const trace={before:null,after:null,snapshot(position,kind,status){
    const now=performance.now(),values={...costs};values[phase]+=now-last;
    const duration=Math.max(0,Math.round(now-start)),rounded=Object.fromEntries([...visited].map(key=>[key,Math.max(0,Math.floor(values[key]))]));
    rounded[phase]+=duration-Object.values(rounded).reduce((sum,value)=>sum+value,0);
    return {step_position:position,kind,status,duration_ms:duration,phase_ms:rounded};
  }};
  Object.defineProperty(trace,'phase',{get:()=>phase,set:value=>{
    if(!TIMING_PHASES.includes(value)) throw new WorkerError('未知的受限执行计时阶段','INVALID_TIMING_PHASE');
    const now=performance.now();costs[phase]+=now-last;last=now;phase=value;visited.add(value);
  }});
  return trace;
}

function requireString(value, name, max = 2_000) {
  if (typeof value !== 'string' || !value.trim() || value.length > max) {
    throw new WorkerError(`${name} 必须是非空文本，最多 ${max} 字符`, 'INVALID_INPUT');
  }
  return value.trim();
}

function httpUrl(value) {
  let url;
  try { url = new URL(requireString(value, 'entry_url', 4_096)); }
  catch { throw new WorkerError('仅支持明确的 http 或 https 页面地址', 'INVALID_URL'); }
  if (!['http:', 'https:'].includes(url.protocol) || url.username || url.password) {
    throw new WorkerError('仅支持不含账号密码的 http 或 https 地址', 'INVALID_URL');
  }
  return url;
}

const digest = value => createHash('sha256').update(value).digest('hex');
const redactText = value => String(value || '')
  .replace(/(?:\+?86[-\s]?)?1[3-9]\d{9}(?!\d)/g, '[手机号已隐藏]')
  .replace(/((?:验证码|校验码|动态码|短信码|password|verification\s*code)\s*[:：]?\s*)[\w-]{4,12}/gi, '$1[已隐藏]');

export function redactUrl(value) {
  try {
    const url = new URL(value);
    for (const key of [...url.searchParams.keys()]) {
      if (/password|passwd|phone|mobile|captcha|verification|(?:^|_)code$|token|secret|session|credential/i.test(key)) {
        url.searchParams.set(key, '[已隐藏]');
      }
    }
    if (/token|password|secret|session|credential/i.test(url.hash)) url.hash = '[已隐藏]';
    // A public note ID is an opaque hexadecimal identifier, even when it
    // happens to contain eleven digits matching the phone-number pattern.
    // Preserve only the verified official note path; all other URL parts keep
    // the existing sensitive-key and ordinary-text redaction rules.
    if(url.origin==='https://www.xiaohongshu.com' && !url.username && !url.password && /^\/(?:(?:explore|search_result)\/[a-fA-F0-9]{24}|user\/profile\/[a-fA-F0-9]{24})$/.test(url.pathname)) {
      return url.origin+url.pathname+redactText(url.search+url.hash);
    }
    return redactText(url.href);
  } catch { return redactText(value); }
}

async function chromium() {
  if (!chromiumPromise) chromiumPromise = import('playwright').then(module => module.chromium).catch(() => {
    throw new WorkerError('缺少 Playwright 依赖，请先在项目中安装依赖', 'MISSING_DEPENDENCY');
  });
  return chromiumPromise;
}

function sessionFor(taskId, requireReady = true) {
  const key = requireString(taskId, 'task_id', 128);
  const session = sessions.get(key);
  if (!session || session.closed || session.page.isClosed()) {
    throw new WorkerError('浏览器会话已关闭，请重新打开并人工确认当前页面', 'SESSION_CLOSED');
  }
  if (session.blockedNavigation) {
    throw new WorkerError('页面尝试离开本次学习的站点范围，请关闭会话后检查入口', 'SCOPE_BLOCKED');
  }
  if (session.popupBlocked) throw new WorkerError('出现未知或站点范围外的弹窗，已关闭并暂停，请维护者核对', 'POPUP_BLOCKED');
  if (requireReady && !session.ready) {
    throw new WorkerError('请先在官方页面完成登录，再明确开始观察；登录阶段不采集证据', 'AWAITING_USER');
  }
  if(requireReady && isNativeUiProfile(session.executionProfile)) requireOrigin(session,session.page.url());
  return session;
}

function requireOrigin(session, url) {
  let parsed;
  try { parsed = new URL(url); } catch { throw new WorkerError('当前页面地址不可核验', 'SCOPE_BLOCKED'); }
  if (parsed.origin !== session.origin) {
    throw new WorkerError('当前页面不属于本次学习允许的站点', 'SCOPE_BLOCKED');
  }
  if(isNativeUiProfile(session.executionProfile) && !(session.executionProfile===NAVIGATION_UI_PROFILE ? validNavigationPage(url) : validNativePage(url))) throw new WorkerError('当前页面不在此执行模式声明的搜索或笔记范围','SCOPE_BLOCKED');
}

function boundNoteSource(value, origin) {
  try {
    const url=new URL(value),match=/^\/(?:explore|search_result)\/([a-fA-F0-9]{24})$/.exec(url.pathname);
    return url.origin===origin && !url.username && !url.password && match ?
      {note_id:match[1].toLowerCase(),source_url:url.origin+url.pathname} : null;
  }catch{return null;}
}

function requireBoundNotePage(session,binding) {
  if(!binding?.opened) return;
  const actual=boundNoteSource(session.page.url(),session.origin);
  if(!actual || actual.note_id!==binding.note_id){
    binding.url_checked=false;
    throw new WorkerError('当前笔记来源与本次已选笔记绑定不一致，停止读取','NOTE_BINDING_MISMATCH');
  }
  binding.url_checked=true;
  binding.source_url=actual.source_url;
}

function makeNoteBinding(value,entry,steps,parameters) {
  if(!value || typeof value!=='object' || Array.isArray(value) || Object.keys(value).length!==1 || !Object.hasOwn(value,'note_id') ||
    typeof value.note_id!=='string' || !/^[a-fA-F0-9]{24}$/.test(value.note_id)) throw new WorkerError('笔记绑定必须是明确的公共笔记编号','INVALID_NOTE_BINDING');
  const fail=()=>{throw new WorkerError('笔记绑定仅支持已固化的七步或有界定位八步详情与首层评论合同','NOTE_BINDING_CONTRACT');};
  const official=entry.origin==='https://www.xiaohongshu.com',demo=['127.0.0.1','localhost','[::1]'].includes(entry.hostname);
  if(!official && !demo) fail();
  const seek=steps.length===8 ? steps[3] : null;
  const readingSteps=seek ? steps.filter((_,index)=>index!==3) : steps;
  if(readingSteps.length!==7 || readingSteps.some((step,index)=>step?.kind!==['fill','press','wait','click','wait','extract','extract'][index])) fail();
  try{steps.forEach(validateAction);}catch{fail();}
  const [fill,press,waiting,click,detailWaiting,detail,comments]=readingSteps;
  if(seek && (seek.kind!=='scroll' || !seek.until_target || /^(?:body|html)$/i.test(seek.selector.trim()) || seek.until_target.selector!==click.selector ||
    seek.until_target.field!==click.target?.field || seek.until_target.parameter!==click.target?.parameter || seek.until_target.parameter!=='note_title')) fail();
  if(fill.parameter!=='keyword' || press.selector!==fill.selector || press.key!=='Enter' || waiting.state!=='visible' || !Number.isInteger(waiting.min_count) || waiting.min_count<1 ||
    click.target?.field!=='text' || click.target?.parameter!=='note_title' || detailWaiting.state!=='visible' ||
    typeof parameters.keyword!=='string' || !parameters.keyword.trim() || typeof parameters.note_title!=='string' || !parameters.note_title.trim() || parameters.note_title.length>2000) fail();
  const fieldsMatch=(step,names,content=false)=>step.fields.length===names.length && names.every(name=>{
    const field=step.fields.find(field=>field.name===name);
    return field?.required===true && (name==='comment_id' ? field.source==='attribute' && field.attribute==='id' : field.source==='text' || (content && name==='body' && field.source==='content'));
  });
  if(detail.output_name!=='note_detail' || detail.limit!==1 || detail.target || detail.batch || detail.allow_empty===true || !fieldsMatch(detail,['title','body','author']) ||
    comments.output_name!=='comments' || !comments.row_selector || comments.complete_only!==true || !comments.batch || comments.batch.dedupe_field!=='comment_id' || comments.allow_empty===true ||
    !fieldsMatch(comments,['comment_id','author','body'],true)) fail();
  return {note_id:value.note_id.toLowerCase(),href_checked:false,url_checked:false,source_url:null,title:null,opened:false,note_title:parameters.note_title.trim(),seek_timeout_ms:seek?.timeout_ms || 0};
}

const bindingResult=binding=>({note_id:binding.note_id,href_checked:binding.href_checked,url_checked:binding.url_checked,source_url:binding.source_url,title:binding.title});

function safePathname(pathname) {
  return pathname.split('/').map(segment => {
    let decoded;
    try { decoded = decodeURIComponent(segment); } catch { return ':redacted'; }
    if (/password|passwd|credential|token|secret|session|cookie|authorization|captcha|verification|phone|mobile|验证码|密码|手机号/i.test(decoded)) return ':redacted';
    if (/(?:\+?86[-\s]?)?1[3-9]\d{9}(?!\d)/.test(decoded) || decoded.length > 64 ||
        /^[a-f0-9-]{16,}$/i.test(decoded) || /^[A-Za-z0-9_=-]{32,}$/.test(decoded) || decoded.includes('@')) return ':id';
    return segment;
  }).join('/').slice(0, 300);
}

function observeRequest(session, request) {
  if (!['document', 'fetch', 'xhr'].includes(request.resourceType())) return null;
  let url;
  try { url = new URL(request.url()); } catch { return null; }
  if (!['http:', 'https:'].includes(url.protocol)) return null;
  const record = { sequence: ++session.requestSequence, recorded_at: new Date().toISOString(),
    method: request.method().slice(0, 16), origin: url.origin, pathname: safePathname(url.pathname),
    resource_type: request.resourceType().slice(0, 32), automating: session.automating, blocked: false };
  session.requestObservations.push(record);
  if (session.requestObservations.length > 30) session.requestObservations.shift();
  return record;
}

function recordBlockedRequest(session, request, observation, decision) {
  const policyDiagnostic=decision ? {policy_reason:decision.reason,
    ...(decision.policy_version ? {active_policy_version:decision.policy_version} : {}),
    ...(decision.expected_resource_types ? {expected_resource_types:[...decision.expected_resource_types]} : {})} : {};
  if (observation) Object.assign(observation,{blocked:true},policyDiagnostic);
  const diagnostic = session.actionDiagnostics;
  if (!diagnostic) return;
  diagnostic.blocked_request_count += 1;
  if (diagnostic.blocked_requests.length >= MAX_BLOCKED_REQUESTS) return;
  let url;
  try { url = new URL(request.url()); } catch { return; }
  // Deliberately omit query/hash, request bodies, headers and credentials.
  const summary = { method: request.method().slice(0, 16), origin: url.origin,
    pathname: safePathname(url.pathname), resource_type: request.resourceType().slice(0, 32),...policyDiagnostic };
  if (!diagnostic.blocked_requests.some(previous => JSON.stringify(previous)===JSON.stringify(summary))) {
    diagnostic.blocked_requests.push(summary);
  }
}

function recordPopup(session, popup, phase, decision, reason) {
  const record = { sequence: ++session.popupSequence, recorded_at: new Date().toISOString(), phase, decision, reason };
  let url;
  try { url = new URL(popup.url()); } catch { url = null; }
  if (url && ['http:', 'https:'].includes(url.protocol)) {
    record.origin = url.origin;
    record.pathname = safePathname(url.pathname);
  }
  session.popupObservations.push(record);
  if (session.popupObservations.length > 10) session.popupObservations.shift();
}

function watchPage(session, page) {
  page.on('close', () => {
    // Closing a former search tab must not invalidate the adopted detail tab.
    if (session.page !== page || session.closed || session.popupPermission?.opener === page ||
        (!session.ready && !session.automating && session.pendingPopups.size > 0)) return;
    session.closed = true;
    session.ready = false;
    session.lastCapture = null;
    void closeContext(session);
  });
}

// Only fixed Page/Frame objects obtained from Playwright are passed here. This
// decides ownership of the existing capability; it never issues or renews one.
export function nativePopupRequestContext({executionProfile,automating,policy,policyPage,currentPage,permission,requestPage,requestFrame,popupOpener,now=Date.now()}){
  try{
    if(executionProfile!==NAVIGATION_UI_PROFILE || automating!==true || !policy || policy.version!==NAVIGATION_UI_POLICY_VERSION ||
      policy.scope!=='native_ui' || !Number.isFinite(policy.expiresAt) || !Number.isFinite(now) || now>=policy.expiresAt ||
      !permission || permission.manual || !permission.opener || popupOpener!==permission.opener || requestPage===permission.opener ||
      requestFrame!==requestPage.mainFrame() || requestFrame.page()!==requestPage ||
      !validNavigationPage(permission.sourceUrl) || permission.opener.url()!==permission.sourceUrl ||
      !navigationPopupMatches(permission.expectedUrl,requestPage.url()) ||
      (permission.pendingPopup && permission.pendingPopup!==requestPage)) return null;
    const before=permission.adopted===false && currentPage===permission.opener && policyPage===permission.opener;
    const after=permission.adopted===true && currentPage===requestPage && policyPage===requestPage && permission.pendingPopup===requestPage;
    return before || after ? {activeMainFrame:true,pageUrl:requestPage.url()} : null;
  }catch{return null;}
}

function receivePopup(session, popup) {
  const manual = !session.ready && !session.automating;
  const phase = manual ? 'manual' : session.automating ? 'automation' : 'confirmed';
  const permission = session.popupPermission || (manual ? { opener: session.page, adopted: false, manual: true } : null);
  const pending = (async () => {
    const opener = await popup.opener().catch(() => null);
    if (!permission || permission.adopted || (opener && opener !== permission.opener) || session.closed || shuttingDown) {
      session.popupBlocked = true;
      recordPopup(session, popup, phase, 'blocked', 'unrequested_popup');
      await popup.close().catch(() => {});
      return;
    }
    if(session.executionProfile===NAVIGATION_UI_PROFILE && !permission.manual){
      if(permission.pendingPopup && permission.pendingPopup!==popup){
        session.popupBlocked=true;
        recordPopup(session,popup,phase,'blocked','unrequested_popup');
        await popup.close().catch(()=>{});
        return;
      }
      permission.pendingPopup=popup;
    }
    // The context route checks every top-level navigation, including this
    // popup's first request, before this event can adopt it.
    // about:blank may already have fired domcontentloaded when context emits
    // page. Wait for the actual bounded navigation before checking the URL.
    await popup.waitForURL(url => ['http:', 'https:'].includes(url.protocol), { waitUntil: 'domcontentloaded', timeout: 3_000 }).catch(() => {});
    let url;
    try { url = new URL(popup.url()); } catch { url = null; }
    if (!url || !['http:', 'https:'].includes(url.protocol) || url.origin !== session.origin ||
        (session.executionProfile===NAVIGATION_UI_PROFILE && (!validNavigationPage(url.href) || (!permission.manual && !navigationPopupMatches(permission.expectedUrl,url.href)))) ||
        url.username || url.password || session.blockedNavigation || permission.adopted ||
        (!permission.manual && !opener && (session.executionProfile===NAVIGATION_UI_PROFILE ?
          !navigationPopupMatches(permission.expectedUrl,url.href) : (!permission.expectedUrl || url.href !== permission.expectedUrl)))) {
      session.popupBlocked = true;
      recordPopup(session, popup, phase, 'blocked', !url || !['http:', 'https:'].includes(url.protocol) ? 'unconfirmed_origin' :
        url.origin !== session.origin || session.blockedNavigation ? 'outside_scope' : 'unrequested_popup');
      await popup.close().catch(() => {});
      return;
    }
    const transferred=nativePopupRequestContext({executionProfile:session.executionProfile,automating:session.automating,
      policy:session.platformRequestPolicy,policyPage:session.platformRequestPage,currentPage:session.page,
      permission,requestPage:popup,requestFrame:popup.mainFrame(),popupOpener:opener});
    permission.adopted = true;
    watchPage(session, popup);
    session.page = popup;
    if(transferred) session.platformRequestPage=popup;
    session.lastCapture = null;
    // A same-origin page opened during manual login remains a page awaiting
    // confirmation; adopting the page never authorizes automated actions.
    if (permission.manual) session.ready = false;
    recordPopup(session, popup, phase, 'adopted', permission.manual ? 'same_origin_manual' : 'same_origin_click');
  })();
  session.pendingPopups.add(pending);
  void pending.finally(() => {
    session.pendingPopups.delete(pending);
    if (!session.ready && !session.automating && !session.pendingPopups.size && session.page.isClosed() && !session.closed) {
      session.closed = true;
      session.lastCapture = null;
      void closeContext(session);
    }
  }).catch(() => {});
}

async function settlePopups(session) {
  while (session.pendingPopups.size) await Promise.all([...session.pendingPopups]);
  if (session.popupBlocked) throw new WorkerError('出现未获明确点击授权或站点范围外的弹窗，已关闭并暂停', 'POPUP_BLOCKED');
  if (session.blockedNavigation) throw new WorkerError('页面尝试离开本次学习站点，已阻止并暂停', 'SCOPE_BLOCKED');
}

async function settle(page) {
  await page.waitForLoadState('domcontentloaded', { timeout: 3_000 }).catch(() => {});
  await page.waitForTimeout(180);
}

async function refreshLoginDetection(session) {
  session.loginDetection = await detectSession(session.page);
  if (['logged_out', 'verification_required'].includes(session.loginDetection.state)) {
    session.ready = false;
    session.lastCapture = null;
  }
  return session.loginDetection;
}

async function open(params) {
  const taskId = requireString(params.task_id, 'task_id', 128);
  const accountKey = requireString(params.account_key, 'account_key', 256);
  const entry = httpUrl(params.entry_url);
  resolveExecutionProfile(params.execution_profile);
  if(isNativeUiProfile(params.execution_profile) && !(params.execution_profile===NAVIGATION_UI_PROFILE ? validNavigationPage(entry.href) : validNativePage(entry.href))) throw new WorkerError('新执行模式仅支持已声明的小红书官网搜索或笔记页面','EXECUTION_PROFILE_INVALID');
  const existing = sessions.get(taskId);
  if (existing && !existing.closed && !existing.page.isClosed()) {
    if (existing.accountKey !== accountKey || existing.origin !== entry.origin || existing.executionProfile!==params.execution_profile) {
      throw new WorkerError('当前任务已经持有不同的账号或站点会话，请先关闭', 'SESSION_CONFLICT');
    }
    await refreshLoginDetection(existing);
    return sessionInfo(existing);
  }
  const accountId = digest(`${entry.origin}\0${accountKey}`);
  if (closingAccounts.has(accountId)) await closingAccounts.get(accountId);
  const owner = accountOwners.get(accountId);
  if (owner && owner !== taskId) {
    throw new WorkerError('同一平台账号正在被另一学习任务使用，请先关闭原会话', 'ACCOUNT_BUSY');
  }
  const profile = path.join(HOME, 'profiles', accountId);
  await fs.mkdir(profile, { recursive: true });
  accountOwners.set(accountId, taskId);
  let context;
  try {
    const browserType = await chromium();
    if (shuttingDown) throw new WorkerError('学习工作进程正在退出', 'WORKER_CLOSING');
    context = await browserType.launchPersistentContext(profile, {
      channel: CHANNEL,
      headless: HEADLESS,
      viewport: { width: 1280, height: 840 },
      acceptDownloads: false,
      timeout: 30_000,
    });
    contexts.add(context);
    context.once('close', () => contexts.delete(context));
    // An EOF may arrive while launching. Never expose a newly launched context
    // after shutdown has already taken its snapshot of active contexts.
    if (shuttingDown) throw new WorkerError('学习工作进程正在退出', 'WORKER_CLOSING');
    const page = context.pages()[0] || await context.newPage();
    await Promise.allSettled(context.pages().filter(other => other !== page).map(other => other.close()));
    page.setDefaultTimeout(TIMEOUT);
    const session = {
      taskId, accountKey, accountId, context, page, origin: entry.origin,executionProfile:params.execution_profile,
      entryUrl: entry.href, sessionId: randomUUID(), ready: false, closed: false,
      identityLabel: null, lastCapture: null, blockedNavigation: null,
      loginDetection: null,
      observedSelectors: new Set(),
      automating: false, blockedWrites: 0, actionDiagnostics: null,
      popupPermission: null, pendingPopups: new Set(), popupBlocked: false,
      requestSequence: 0, requestObservations: [],
      popupSequence: 0, popupObservations: [],
      platformRequestPolicy: null, platformRequestPage: null,
    };
    await context.route('**/*', async route => {
      const request = route.request();
      const observation = observeRequest(session, request);
      let topLevelNavigation = false;
      if (request.isNavigationRequest()) {
        // A popup's first navigation can arrive before Playwright creates its
        // Frame. Treat that case as top-level; never bypass its scope check.
        try { topLevelNavigation = request.frame().parentFrame() === null; }
        catch { topLevelNavigation = true; }
      }
      if (topLevelNavigation) {
        let target;
        try { target = new URL(request.url()); } catch { target = null; }
        if (!target || target.origin !== session.origin || (session.executionProfile===NAVIGATION_UI_PROFILE && !validNavigationPage(target.href))) {
          session.blockedNavigation = true;
          recordBlockedRequest(session, request, observation,{reason:'navigation_out_of_scope'});
          await route.abort('blockedbyclient').catch(() => {});
          return;
        }
      }
      // Unknown non-GET requests remain blocked. Only the finite experimental
      // official UI action policy can allow its observed auxiliary requests.
      // Human login does not use the automation flag.
      if (session.automating && !['GET', 'HEAD', 'OPTIONS'].includes(request.method())) {
        let activeMainFrame = false;
        let policyPageUrl=session.page.url();
        try {
          const frame=request.frame(),requestPage=frame.page(),permission=session.popupPermission;
          if(session.executionProfile===NAVIGATION_UI_PROFILE && permission && requestPage!==permission.opener){
            const popupOpener=await requestPage.opener();
            if(session.popupPermission===permission){
              const popupContext=nativePopupRequestContext({executionProfile:session.executionProfile,automating:session.automating,
                policy:session.platformRequestPolicy,policyPage:session.platformRequestPage,currentPage:session.page,
                permission,requestPage,requestFrame:frame,popupOpener});
              if(popupContext){
                if(!permission.pendingPopup) permission.pendingPopup=requestPage;
                activeMainFrame=popupContext.activeMainFrame;policyPageUrl=popupContext.pageUrl;
              }
            }
          }else activeMainFrame=session.platformRequestPage===session.page && frame===session.page.mainFrame();
        } catch {}
        const policyDecision = evaluatePlatformRequest({ policy: session.platformRequestPolicy, automating: session.automating,
          sessionOrigin: session.origin, pageUrl: policyPageUrl, activeMainFrame,
          method: request.method(), resourceType: request.resourceType(), url: request.url() });
        if (policyDecision.allowed) {
          if (observation) Object.assign(observation,{policy_version:policyDecision.policy_version,policy_rule:policyDecision.policy_rule});
          await route.continue().catch(() => {});
          return;
        }
        session.blockedWrites += 1;
        recordBlockedRequest(session, request, observation,policyDecision);
        await route.abort('blockedbyclient').catch(() => {});
        return;
      }
      await route.continue().catch(() => {});
    });
    context.on('page', popup => { if (popup !== session.page) receivePopup(session, popup); });
    const markClosed = () => {
      session.closed = true;
      session.ready = false;
      session.lastCapture = null;
      if (accountOwners.get(accountId) === taskId) accountOwners.delete(accountId);
    };
    context.on('close', markClosed);
    watchPage(session, page);
    sessions.set(taskId, session);
    await page.goto(entry.href, { waitUntil: 'domcontentloaded', timeout: 25_000 });
    requireOrigin(session, page.url());
    await settle(page);
    await refreshLoginDetection(session);
    return sessionInfo(session);
  } catch (error) {
    if (context) await context.close().catch(() => {});
    sessions.delete(taskId);
    if (accountOwners.get(accountId) === taskId) accountOwners.delete(accountId);
    if (/executable|browser.*not found|distribution.*not found/i.test(error.message)) {
      throw new WorkerError(`浏览器不可用。请安装 Playwright Chromium，或配置本机已安装的浏览器通道。当前通道 ${CHANNEL}`, 'BROWSER_UNAVAILABLE');
    }
    throw error;
  }
}

function sessionInfo(session) {
  return {
    ...executionMetadata(session.executionProfile),
    session_id: session.sessionId,
    status: session.closed ? 'closed' : session.ready ? 'observing' : 'awaiting_user',
    url: redactUrl(session.page.url()),
    manual_confirmation: session.ready,
    identity_label: session.identityLabel,
    login_detection: session.loginDetection,
    block_reason: session.blockedNavigation ? 'scope_blocked' : session.popupBlocked ? 'popup_blocked' : null,
    popup_observations: session.popupObservations.map(record => ({ ...record })),
  };
}

async function ready(params) {
  const session = sessionFor(params.task_id, false);
  await settlePopups(session);
  requireOrigin(session, session.page.url());
  const detection = await refreshLoginDetection(session);
  if (detection.state === 'logged_out') throw new WorkerError('当前可见页面仍要求登录，请在官方页面完成后重新确认', 'LOGIN_REQUIRED');
  if (detection.state === 'verification_required') throw new WorkerError('当前可见页面需要人工验证，请在官方页面处理后重新确认', 'VERIFICATION_REQUIRED');
  const label = requireString(params.identity_label, 'identity_label', 100);
  if (/(?:\+?86[-\s]?)?1[3-9]\d{9}|验证码|password|密码/i.test(label)) {
    throw new WorkerError('确认标签请使用测试账号昵称或代号，不填写手机号、密码或验证码', 'SENSITIVE_INPUT');
  }
  session.ready = true;
  session.identityLabel = label;
  session.lastCapture = null;
  return { ...sessionInfo(session), identity_verification: 'operator_confirmed',
    note: '此记录是维护者人工确认，不代表自动完成平台账号身份核验' };
}

export async function describePage(page,request=null) {
  return page.evaluate(request => {
    const metadataOnly=Boolean(request?.selector);
    const PRIVATE = /password|passwd|credential|token|secret|cookie|authorization|session|one.time.code|verification|captcha|phone|mobile|(?:^|[-_])tel(?:$|[-_])|sms|验证码|校验码|动态码|短信码|手机号|手机号码|密码|口令|登录|登陆|sign.?in|log.?in/i;
    const phone = /(?:\+?86[-\s]?)?1[3-9]\d{9}(?!\d)/g;
    const clean = text => String(text || '').replace(phone, '[手机号已隐藏]').trim();
    // This evaluate callback is synchronous and makes no DOM writes. Reuse the
    // same node facts only within this observation; scrolling, style changes
    // and later captures always start with fresh caches.
    const memo = read => {
      const values = new WeakMap();
      return element => {
        if (!values.has(element)) values.set(element, read(element));
        return values.get(element);
      };
    };
    const rectFor = memo(element => element.getBoundingClientRect());
    const styleFor = memo(element => getComputedStyle(element));
    const fieldLabel = memo(element => {
      const id = element.id;
      const explicit = id ? document.querySelector(`label[for="${CSS.escape(id)}"]`)?.textContent : '';
      return [element.getAttribute('aria-label'), element.getAttribute('placeholder'), explicit,
        element.getAttribute('title'), element.getAttribute('name'), element.getAttribute('autocomplete'), element.id]
        .filter(Boolean).join(' ').trim();
    });
    const stableFieldLabel = memo(element => {
      const explicit = element.id ? document.querySelector(`label[for="${CSS.escape(element.id)}"]`)?.textContent : '';
      const fields = [element.getAttribute('aria-label'),element.getAttribute('title'),element.getAttribute('name'),explicit,element.id,
        element.getAttribute('type') || (element.tagName==='INPUT' ? 'text' : 'textarea'),element.getAttribute('autocomplete')]
        .map(value=>clean(value).replace(/\s+/g,' '));
      const result = JSON.stringify(fields);
      return fields.some(Boolean) && result.length<=500 ? result : '';
    });
    const isSensitive = memo(element => {
      if (element.matches('input[type=password],input[type=tel],[autocomplete="one-time-code"]')) return true;
      if (PRIVATE.test(fieldLabel(element))) return true;
      for (let parent = element.parentElement; parent; parent = parent.parentElement) {
        if (PRIVATE.test([parent.id, parent.getAttribute('aria-label'), parent.getAttribute('title')].filter(Boolean).join(' '))) return true;
      }
      const form = element.closest('form,[role=dialog]');
      return Boolean(form && (form.querySelector('input[type=password],input[type=tel],[autocomplete="one-time-code"]') ||
        PRIVATE.test([form.getAttribute('id'), form.getAttribute('class'), form.getAttribute('aria-label'), form.textContent?.slice(0, 1200)].join(' '))));
    });
    const visible = memo(element => {
      const rect = rectFor(element);
      if (rect.width <= 0 || rect.height <= 0) return false;
      for (let current = element; current; current = current.parentElement) {
        const style = styleFor(current);
        if (style.display === 'none' || ['hidden', 'collapse'].includes(style.visibility) || Number(style.opacity) === 0) return false;
      }
      return true;
    });
    const inViewport = memo(element => {
      const rect = rectFor(element);
      let top = Math.max(0, rect.top), bottom = Math.min(innerHeight, rect.bottom);
      let left = Math.max(0, rect.left), right = Math.min(innerWidth, rect.right);
      for (let parent = element.parentElement; parent; parent = parent.parentElement) {
        const style = styleFor(parent), box = rectFor(parent);
        if (/(?:auto|scroll|hidden|clip)/.test(style.overflowY)) { top = Math.max(top, box.top); bottom = Math.min(bottom, box.bottom); }
        if (/(?:auto|scroll|hidden|clip)/.test(style.overflowX)) { left = Math.max(left, box.left); right = Math.min(right, box.right); }
      }
      return visible(element) && bottom > top && right > left;
    });
    const selectorFor = element => {
      if (element.getAttribute('data-testid')) return `[data-testid=${JSON.stringify(element.getAttribute('data-testid'))}]`;
      if (element.id) return `#${CSS.escape(element.id)}`;
      if (element.getAttribute('data-learning-read')) return `[data-learning-read=${JSON.stringify(element.getAttribute('data-learning-read'))}]`;
      const segments = [];
      let current = element;
      for (let level = 0; current && current !== document.body && level < 7; level += 1, current = current.parentElement) {
        if (current.id) { segments.unshift(`#${CSS.escape(current.id)}`); break; }
        const tag = current.tagName.toLowerCase();
        const siblings = current.parentElement ? Array.from(current.parentElement.children).filter(node => node.tagName === current.tagName) : [];
        segments.unshift(siblings.length > 1 ? `${tag}:nth-of-type(${siblings.indexOf(current) + 1})` : tag);
      }
      return segments.join(' > ');
    };
    const rawTextCaches = [new WeakMap(), new WeakMap()];
    const displayedText = (root, viewportOnly = false) => {
      const cache = rawTextCaches[Number(viewportOnly)];
      const walk = node => {
        if (cache.has(node)) return cache.get(node);
        let text = '';
        if (node.nodeType === Node.TEXT_NODE) text = node.textContent;
        else if (node.nodeType === Node.ELEMENT_NODE && !node.matches('script,style,noscript,iframe,input,textarea,select,[contenteditable=true]') &&
            !isSensitive(node) && visible(node) && (!viewportOnly || inViewport(node))) {
          text = Array.from(node.childNodes, walk).join(' ');
        }
        cache.set(node, text);
        return text;
      };
      return clean(walk(root)).replace(/\s+/g, ' ').slice(0, 16_000);
    };
    const text = metadataOnly ? '' : displayedText(document.body);
    const viewportText = metadataOnly ? '' : displayedText(document.body, true);
    const elements = [], seen = new Set(), masks = new Set();
    for (const element of metadataOnly ? [] : document.querySelectorAll('body *')) {
      if (PRIVATE.test([element.id, element.getAttribute('aria-label'), element.getAttribute('title')].filter(Boolean).join(' '))) {
        masks.add(selectorFor(element));
      }
      if (element.children.length === 0 && /(?:\+?86[-\s]?)?1[3-9]\d{9}(?!\d)/.test(element.textContent || '')) {
        masks.add(selectorFor(element));
      }
    }
    const safeToken = value => /^[A-Za-z][A-Za-z0-9_-]{0,95}$/.test(value || '') && !PRIVATE.test(value) && !/(?:\+?86[-\s]?)?1[3-9]\d{9}(?!\d)/.test(value);
    const readable = memo(element => !element.matches('script,style,noscript,iframe,input,textarea,select,[contenteditable=true]') && !isSensitive(element));
    const scrollInfo = memo(element => {
      if (!readable(element) || !/(?:auto|scroll)/.test(styleFor(element).overflowY) || element.clientHeight <= 0) return null;
      return { can_scroll: element.scrollHeight > element.clientHeight + 1, scroll_top: element.scrollTop,
        scroll_height: element.scrollHeight, client_height: element.clientHeight };
    });
    const relativeSelector = (root, element) => {
      if (safeToken(element.id)) return `#${CSS.escape(element.id)}`;
      for (const name of [...element.classList].filter(safeToken).slice(0, 3)) {
        const selector = `${element.tagName.toLowerCase()}.${CSS.escape(name)}`;
        if (root.querySelectorAll(selector).length === 1) return selector;
      }
      const parts = [];
      for (let current = element; current && current !== root && parts.length < 6; current = current.parentElement) {
        const tag = current.tagName.toLowerCase();
        const siblings = [...current.parentElement.children].filter(node => node.tagName === current.tagName);
        parts.unshift(siblings.length > 1 ? `${tag}:nth-of-type(${siblings.indexOf(current) + 1})` : tag);
        if (current.parentElement === root) return `:scope > ${parts.join(' > ')}`;
      }
      return null;
    };
    const readHints = root => {
      const hints = [], seenHints = new Set();
      const media=[...root.querySelectorAll('img,video')].slice(0,40).filter(element=>visible(element) && readable(element) && !element.closest('a') &&
        ![element,...function*(node){for(let parent=node.parentElement;parent;parent=parent.parentElement) yield parent;}(element)].some(node=>/avatar|头像/i.test([node.id,...node.classList].join(' '))))
        .sort((a,b)=>Number(inViewport(b))-Number(inViewport(a))).slice(0,4);
      for(const child of media){
        const selector=relativeSelector(root,child);if(!selector || selector.length>350 || seenHints.has(selector)) continue;
        const image=child.tagName==='IMG',count=root.querySelectorAll(selector).length;
        seenHints.add(selector);hints.push({selector,tag:child.tagName.toLowerCase(),label:image ? '图片元素（未解释）' : '视频元素（未解释）',unique:count===1,count,
          in_viewport:inViewport(child),link:false,source:'media',media_kind:image ? 'image' : 'video',loaded:image ? child.complete && child.naturalWidth>0 : child.readyState>=2 && child.videoWidth>0});
      }
      const children = [...root.querySelectorAll('a,h1,h2,h3,h4,h5,h6,p,time,span,div[id],div[class]')].slice(0, 200)
        .filter(element => visible(element) && readable(element))
        .sort((a, b) => Number(inViewport(b)) - Number(inViewport(a)) || Number(b.children.length === 0) - Number(a.children.length === 0));
      for (const child of children) {
        if (hints.length >= 12) break;
        const selector = relativeSelector(root, child);
        if (!selector || selector.length > 350 || seenHints.has(selector)) continue;
        const count = root.querySelectorAll(selector).length;
        const label = displayedText(child).slice(0, 100);
        if (!label) continue;
        seenHints.add(selector);
        const link = child.tagName === 'A';
        const datetime = child.tagName === 'TIME' && child.hasAttribute('datetime');
        hints.push({ selector, tag: child.tagName.toLowerCase(), label, unique: count === 1, count,
          in_viewport: inViewport(child), link, source: datetime ? 'attribute' : link ? 'href' : 'text', ...(datetime ? { attribute: 'datetime' } : {}) });
      }
      return hints;
    };
    const elementMetadata=(element,selector,count)=>{
      const tag=element.tagName.toLowerCase();
      const kind=['input','textarea'].includes(tag) ? 'fill' : (tag==='button' || tag==='a' || element.getAttribute('role')==='button') ? 'click' : 'read';
      if(!visible(element) || isSensitive(element) || element.hasAttribute('disabled') ||
        (kind==='fill' && !['text','search','url',''].includes((element.getAttribute('type') || '').toLowerCase()))) return null;
      let label=kind==='fill' ? fieldLabel(element) : displayedText(element);
      label=clean(label || element.getAttribute('aria-label') || tag).slice(0,180) || tag;
      const searchDescription=[element.getAttribute('type'),element.id,fieldLabel(element)].filter(Boolean).join(' ');
      const form=element.form || element.closest('form');
      const searchForm=form && (form.getAttribute('method') || 'get').toLowerCase()==='get' &&
        (/search|query|搜索|查询|检索/i.test([form.getAttribute('action'),form.getAttribute('role')].join(' ')) ||
          [...form.querySelectorAll('button,input[type=submit]')].some(button=>/search|搜索|查询|检索/i.test([button.textContent,button.getAttribute('aria-label'),button.getAttribute('value')].join(' '))));
      const search_input=kind==='fill' && !/comment|reply|message|私信|评论|回复|发言|留言|发送/i.test(searchDescription) &&
        (!form || (form.getAttribute('method') || 'get').toLowerCase()==='get') && (/search|query|keyword|搜索|查询|检索/i.test(searchDescription) || Boolean(searchForm));
      const scroll_y=scrollInfo(element);
      return {selector,tag,label,kind,unique:count===1,count,sensitive:false,in_viewport:inViewport(element),search_input,
        ...(search_input ? {stable_label:stableFieldLabel(element)} : {}),
        selector_basis:safeToken(element.id) ? 'id' : scroll_y ? 'scroll_container' : 'semantic',...(scroll_y ? {scroll_y} : {})};
    };
    if(metadataOnly){
      const matches=[...document.querySelectorAll(request.selector)];
      if(matches.length>500) return {elements:[],read_limit:true};
      if(!matches.length || matches.some(element=>isSensitive(element))) return {elements:[]};
      if(request.requireCanonical && matches.some(element=>selectorFor(element)!==request.selector)) return {elements:[]};
      const first=matches.find(element=>visible(element) && inViewport(element)) || (!request.collection && matches.find(visible));
      if(!first || matches.some(element=>element.tagName!==first.tagName) || (request.collection && matches.some(element=>!readable(element)))) return {elements:[]};
      const metadata=elementMetadata(first,request.selector,matches.length);
      return {elements:metadata ? [metadata] : []};
    }
    const base = [...document.querySelectorAll('input,textarea,button,a,[data-testid],[data-learning-read],main,article,[role=main],[role=button]')];
    const semantic = [...document.querySelectorAll('body [id],h1,h2,h3,h4,h5,h6,section,[role=heading],[role=region],[role=list],[role=listitem]')]
      .slice(0, 2000).filter(element => readable(element) && (safeToken(element.id) || element.matches('h1,h2,h3,h4,h5,h6,section,[role=heading],[role=region],[role=list],[role=listitem]')));
    const scrollRoots = new Set();
    for (const element of [...semantic, ...base].filter(inViewport).slice(0, 240)) {
      for (let parent = element, depth = 0; parent && parent !== document.body && depth < 7; parent = parent.parentElement, depth += 1) {
        if (scrollInfo(parent)) scrollRoots.add(parent);
      }
    }
    const foreground = memo(element => {
      if (!inViewport(element)) return false;
      const rect = rectFor(element);
      const hit = document.elementFromPoint(Math.max(0, Math.min(innerWidth - 1, (Math.max(0, rect.left) + Math.min(innerWidth, rect.right)) / 2)),
        Math.max(0, Math.min(innerHeight - 1, (Math.max(0, rect.top) + Math.min(innerHeight, rect.bottom)) / 2)));
      return Boolean(hit && (hit === element || element.contains(hit)));
    });
    const controlRank = element => element.matches('input,textarea') ? 0 : element.matches('button,[role=button]') ? 1 : element.tagName==='A' ? 3 : 2;
    const candidates = [...new Set([...semantic, ...scrollRoots, ...base])]
      .sort((a, b) => Number(inViewport(b)) - Number(inViewport(a)) || controlRank(a)-controlRank(b) || Number(foreground(b))-Number(foreground(a)));
    let loadedOffscreen = 0;
    let readCount = 0, hintedRoots = 0, fillCount = 0, buttonCount = 0;
    for (const element of candidates) {
      if (!visible(element)) continue;
      const selector = selectorFor(element);
      if (!selector) continue;
      if (isSensitive(element)) {
        const form = element.closest('form,[role=dialog]');
        masks.add(selectorFor(form || element));
        continue;
      }
      if (seen.has(selector) || elements.length >= 108) continue;
      const in_viewport = inViewport(element);
      if (!in_viewport && loadedOffscreen >= 30) continue;
      const tag = element.tagName.toLowerCase();
      const kind = ['input', 'textarea'].includes(tag) ? 'fill' : (tag === 'button' || tag === 'a' || element.getAttribute('role') === 'button') ? 'click' : 'read';
      if (kind === 'read' && readCount >= 48) continue;
      if ((kind==='fill' && fillCount>=16) || (kind==='click' && tag!=='a' && buttonCount>=24)) continue;
      if (kind === 'fill' && !['text','search','url',''].includes((element.getAttribute('type') || '').toLowerCase())) continue;
      if (element.hasAttribute('disabled')) continue;
      let count = 0;
      try { count = document.querySelectorAll(selector).length; } catch { continue; }
      seen.add(selector);
      if (kind === 'read') readCount += 1;
      if (kind === 'fill') fillCount += 1;
      if (kind === 'click' && tag!=='a') buttonCount += 1;
      if (!in_viewport) loadedOffscreen += 1;
      const metadata=elementMetadata(element,selector,count);
      if(!metadata) continue;
      const structure = kind === 'read' && hintedRoots < 16 ? readHints(element) : [];
      if (structure.length) hintedRoots += 1;
      elements.push({...metadata,...(structure.length ? {read_hints:structure} : {})});
    }
    const addCollection = (selector, basis, sources) => {
      if (elements.length >= 120 || seen.has(selector) || selector.length > 1000) return;
      let matches;
      try { matches = [...document.querySelectorAll(selector)]; } catch { return; }
      if (!matches.length || matches.length > 200 || matches.some(element => !readable(element))) return;
      const first = matches.find(element => visible(element) && inViewport(element));
      if (!first || matches.some(element => element.tagName !== first.tagName)) return;
      const tag = first.tagName.toLowerCase(), kind = tag === 'a' ? 'click' : 'read';
      if (kind === 'click' && matches.some(element => !(element instanceof HTMLAnchorElement))) return;
      seen.add(selector);
      elements.push({ selector, tag, label: displayedText(first).slice(0,180) || tag, kind, unique: matches.length === 1,
        count: matches.length, sensitive:false, in_viewport:true, search_input:false, collection:true, selector_basis:basis,
        source_selectors:sources.slice(0,3), read_hints:readHints(first) });
    };
    for (const element of candidates.filter(element => readable(element) && visible(element) && inViewport(element)).slice(0, 400)) {
      if (elements.length >= 120) break;
      const family = safeToken(element.id) && element.id.match(/^([A-Za-z][A-Za-z_-]{1,47}[-_])(?:[a-fA-F0-9]{16,32}|\d{1,12})$/);
      const parent = element.parentElement;
      if (family && parent && parent !== document.body) {
        const scope = selectorFor(parent);
        if (scope && document.querySelectorAll(scope).length === 1) {
          const selector = `${scope} > ${element.tagName.toLowerCase()}[id^=${JSON.stringify(family[1])}]`;
          const members = [...document.querySelectorAll(selector)];
          if (members.every(member => member.id.match(/^([A-Za-z][A-Za-z_-]{1,47}[-_])(?:[a-fA-F0-9]{16,32}|\d{1,12})$/)?.[1] === family[1])) {
            addCollection(selector, 'id_family', members.slice(0,3).map(selectorFor));
          }
        }
      }
      for (const name of [...element.classList].filter(safeToken).slice(0, 2)) {
        for (let scopeNode = parent, depth = 0; scopeNode && scopeNode !== document.body && depth < 12; scopeNode = scopeNode.parentElement, depth += 1) {
          if (!safeToken(scopeNode.id) && !scopeNode.matches('main,article,section,[role=main],[role=region]')) continue;
          const scope = selectorFor(scopeNode), selector = `${scope} ${element.tagName.toLowerCase()}.${CSS.escape(name)}`;
          if (!scope || document.querySelectorAll(scope).length !== 1) continue;
          const members = [...document.querySelectorAll(selector)];
          if (members.length >= 2 && members.length <= 200) {
            addCollection(selector, 'sibling_class', members.slice(0,3).map(selectorFor));
            break;
          }
        }
      }
    }
    return { title: clean(document.title).slice(0, 250), text, viewport_text: viewportText,
      text_scope: 'displayed_loaded_dom', viewport: { width: innerWidth, height: innerHeight, scroll_x: scrollX, scroll_y: scrollY },
      elements, masks: [...masks].filter(Boolean) };
  },request);
}

async function describeCurrentSelector(page,selector,observed){
  const current=await describePage(page,{selector,collection:observed?.collection===true,requireCanonical:Boolean(observed && !observed.collection)});
  if(current.read_limit) throw new WorkerError('当前定位超过500个对象，请重新限定范围','READ_LIMIT');
  return current.elements[0];
}

async function captureSession(session, note = '') {
  if (shuttingDown) throw new WorkerError('学习工作进程正在退出', 'WORKER_CLOSING');
  if(session.closed || session.page.isClosed()) throw new WorkerError('浏览器会话已关闭，不能继续采集','SESSION_CLOSED');
  requireOrigin(session, session.page.url());
  const description = await describePage(session.page);
  if(session.closed || session.page.isClosed()) throw new WorkerError('会话已中断，不保存迟到的页面描述','SESSION_CLOSED');
  const captureId = randomUUID();
  const directory = path.join(HOME, 'evidence', digest(session.taskId).slice(0, 24));
  await fs.mkdir(directory, { recursive: true });
  const screenshotPath = path.join(directory, `${captureId}.png`);
  const mask = description.masks.map(selector => session.page.locator(selector));
  mask.push(session.page.locator('input,textarea,[contenteditable=true]'));
  await session.page.screenshot({ path: screenshotPath, fullPage: false, mask, maskColor: '#1d252b', timeout: 10_000 });
  if(session.closed || session.page.isClosed()) throw new WorkerError('浏览器会话已关闭，不追加迟到的采集','SESSION_CLOSED');
  const snapshot = {
    ...executionMetadata(session.executionProfile),
    capture_id: captureId,
    url: redactUrl(session.page.url()),
    title: redactText(description.title),
    text: redactText(description.text),
    viewport_text: redactText(description.viewport_text),
    text_scope: description.text_scope,
    viewport: description.viewport,
    elements: description.elements,
    screenshot_path: screenshotPath,
    relative_screenshot_path: path.relative(HOME, screenshotPath).split(path.sep).join('/'),
    captured_at: new Date().toISOString(),
    note: redactText(note).slice(0, 1000),
    identity_verification: 'operator_confirmed',
    request_observations: session.requestObservations.map(record => ({ ...record })),
    popup_observations: session.popupObservations.map(record => ({ ...record })),
  };
  session.lastCapture = snapshot;
  for (const element of snapshot.elements) if (!element.sensitive) session.observedSelectors.add(element.selector);
  return snapshot;
}

async function capture(params) {
  const session = sessionFor(params.task_id);
  return captureSession(session, params.note || '');
}

const DANGEROUS = /关注|私信|发送|提交|支付|购买|删除|移除|注销|退出登录|确认订单|下单|转账|follow|unfollow|send|submit|purchase|delete|remove|logout|sign.out|pay(?:ment)?/i;
const READ_ONLY_BUTTON = /搜索|查询|检索|筛选|展开|收起|更多|下一页|上一页|刷新|加载|search|filter|expand|collapse|more|next|previous|refresh|load/i;

// Runs only the fixed inspection below, never caller-provided JavaScript.
export function inspectElements(elements, { target, fields, origin, completeOnly, untilSelector, rowSelector, fixedRootSelector, fixedSourceUrl,nativeProfile=false,navigationProfile=false }) {
  if (!Array.isArray(elements)) elements = [elements];
  if(fixedRootSelector && (location.href!==fixedSourceUrl || elements.length!==1 || !elements[0].isConnected ||
      document.querySelectorAll(fixedRootSelector).length!==1 || document.querySelector(fixedRootSelector)!==elements[0])) return [{scope_changed:true}];
  if(rowSelector){
    elements=elements.flatMap(element=>[...element.querySelectorAll(rowSelector)]);
    if(elements.length>500) return [{row_limit:true}];
  }
  const PRIVATE = /password|passwd|credential|token|secret|cookie|authorization|session|one.time.code|verification|captcha|phone|mobile|(?:^|[-_])tel(?:$|[-_])|sms|验证码|校验码|动态码|短信码|手机号|手机号码|密码|口令|登录|登陆|sign.?in|log.?in/i;
  const excluded = 'script,style,noscript,iframe,input,textarea,select,[contenteditable=true]';
  const sensitive = element => {
    const description = [element.getAttribute('aria-label'), element.getAttribute('placeholder'), element.getAttribute('title'),
      element.getAttribute('name'), element.getAttribute('autocomplete'), element.id].filter(Boolean).join(' ');
    if (element.matches('input[type=password],input[type=tel],[autocomplete="one-time-code"]') || PRIVATE.test(description)) return true;
    for (let parent = element.parentElement; parent; parent = parent.parentElement) {
      if (PRIVATE.test([parent.id, parent.getAttribute('aria-label'), parent.getAttribute('title')].filter(Boolean).join(' '))) return true;
    }
    const form = element.closest('form,[role=dialog]');
    return Boolean(form && (form.querySelector('input[type=password],input[type=tel],[autocomplete="one-time-code"]') ||
      PRIVATE.test([form.id, form.className, form.getAttribute('aria-label'), form.textContent?.slice(0, 1200)].join(' '))));
  };
  const visible = element => {
    const rect = element.getBoundingClientRect();
    if (rect.width<=0 || rect.height<=0) return false;
    for (let current=element;current;current=current.parentElement) {
      const style=getComputedStyle(current);
      if (style.display==='none' || ['hidden','collapse'].includes(style.visibility) || Number(style.opacity)===0) return false;
    }
    return true;
  };
  const viewport = element => {
    const rect = element.getBoundingClientRect();
    let top = Math.max(0, rect.top), bottom = Math.min(innerHeight, rect.bottom);
    let left = Math.max(0, rect.left), right = Math.min(innerWidth, rect.right);
    for (let parent = element.parentElement; parent; parent = parent.parentElement) {
      const style = getComputedStyle(parent), box = parent.getBoundingClientRect();
      if (/(?:auto|scroll|hidden|clip)/.test(style.overflowY)) { top = Math.max(top, box.top); bottom = Math.min(bottom, box.bottom); }
      if (/(?:auto|scroll|hidden|clip)/.test(style.overflowX)) { left = Math.max(left, box.left); right = Math.min(right, box.right); }
    }
    return visible(element) && bottom > top && right > left;
  };
  const fullyViewport = (element, container = null) => {
    if (!visible(element)) return false;
    const rect=element.getBoundingClientRect();
    let top=0,bottom=innerHeight,left=0,right=innerWidth;
    for(let parent=element.parentElement;parent;parent=parent.parentElement){
      const style=getComputedStyle(parent),box=parent.getBoundingClientRect();
      if (/(?:auto|scroll|hidden|clip)/.test(style.overflowY)) {top=Math.max(top,box.top+parent.clientTop);bottom=Math.min(bottom,box.top+parent.clientTop+parent.clientHeight);}
      if (/(?:auto|scroll|hidden|clip)/.test(style.overflowX)) {left=Math.max(left,box.left+parent.clientLeft);right=Math.min(right,box.left+parent.clientLeft+parent.clientWidth);}
    }
    if(container){const box=container.getBoundingClientRect();top=Math.max(top,box.top+container.clientTop);bottom=Math.min(bottom,box.top+container.clientTop+container.clientHeight);left=Math.max(left,box.left+container.clientLeft);right=Math.min(right,box.left+container.clientLeft+container.clientWidth);}
    return rect.top>=top-0.5 && rect.bottom<=bottom+0.5 && rect.left>=left-0.5 && rect.right<=right+0.5;
  };
  const clean = value => String(value || '').replace(/\s+/g, ' ').trim().slice(0, 4_000);
  const stableFieldLabel = element => {
    const explicit = element.id ? document.querySelector(`label[for="${CSS.escape(element.id)}"]`)?.textContent : '';
    const fields = [element.getAttribute('aria-label'),element.getAttribute('title'),element.getAttribute('name'),explicit,element.id,
      element.getAttribute('type') || (element.tagName==='INPUT' ? 'text' : 'textarea'),element.getAttribute('autocomplete')]
      .map(value=>String(value || '').replace(/(?:\+?86[-\s]?)?1[3-9]\d{9}(?!\d)/g,'[手机号已隐藏]').replace(/\s+/g,' ').trim());
    const result = JSON.stringify(fields);
    return fields.some(Boolean) && result.length<=500 ? result : '';
  };
  const textOf = root => {
    if (root.matches(excluded) || sensitive(root)) return null;
    const walk = node => {
      if (node.nodeType === Node.TEXT_NODE) return node.textContent;
      if (node.nodeType !== Node.ELEMENT_NODE || node.matches(excluded) || sensitive(node) || !visible(node)) return '';
      return Array.from(node.childNodes, walk).join(' ');
    };
    return clean(walk(root));
  };
  const hrefOf = element => {
    if (!(element instanceof HTMLAnchorElement) || !element.hasAttribute('href')) return null;
    const url = new URL(element.href, document.baseURI);
    if (!['http:', 'https:'].includes(url.protocol) || url.origin !== origin || url.username || url.password) return { error: 'UNSAFE_OUTPUT' };
    return url.href;
  };
  const contentOf=(root,field,row)=>{
    const textNodes=[...root.querySelectorAll(field.text_selector)],mediaNodes=[...root.querySelectorAll(field.media_selector)];
    if(textNodes.length>1) return {error:'NON_UNIQUE_FIELD'};
    if(mediaNodes.length>20) return {error:'READ_LIMIT'};
    if(textNodes.some(node=>node.matches(excluded) || sensitive(node))) return {error:'SENSITIVE_OUTPUT'};
    const textNode=textNodes[0],text=textNode && visible(textNode) ? textOf(textNode) || null : null;
    if(textNode && visible(textNode) && !fullyViewport(textNode) && !completeOnly) return {error:'TARGET_NOT_IN_VIEWPORT'};
    let incomplete=Boolean(completeOnly && (!fullyViewport(row) || !fullyViewport(root) || (textNode && visible(textNode) && !fullyViewport(textNode))));
    const media=[];
    for(const node of mediaNodes){
      if(!['IMG','VIDEO'].includes(node.tagName) || sensitive(node)) return {error:'SENSITIVE_OUTPUT'};
      if(node.closest('a')) return {error:'UNSAFE_CONTENT_MEDIA'};
      for(let parent=node;parent;parent=parent.parentElement) if(/avatar|头像/i.test([parent.id,...parent.classList].join(' '))) return {error:'UNSAFE_CONTENT_MEDIA'};
      const shown=visible(node),complete=shown && fullyViewport(node);
      const loaded=node.tagName==='IMG' ? node.complete && node.naturalWidth>0 : node.readyState>=2 && node.videoWidth>0;
      if(completeOnly && shown && !complete) incomplete=true;
      if(!shown) continue;
      if(!loaded){if(incomplete) continue;return {error:'CONTENT_MEDIA_NOT_READY'};}
      if(!complete && !completeOnly) return {error:'TARGET_NOT_IN_VIEWPORT'};
      const safeToken=value=>/^[A-Za-z][A-Za-z0-9_-]{0,95}$/.test(value || '') && !PRIVATE.test(value) && !/(?:\+?86[-\s]?)?1[3-9]\d{9}(?!\d)/.test(value);
      let selector=safeToken(node.id) ? '#'+CSS.escape(node.id) : null;
      for(const name of [...node.classList].filter(safeToken).slice(0,3)) if(!selector && root.querySelectorAll(node.tagName.toLowerCase()+'.'+CSS.escape(name)).length===1) selector=node.tagName.toLowerCase()+'.'+CSS.escape(name);
      if(!selector){
        const parts=[];
        for(let current=node;current && current!==root && parts.length<8;current=current.parentElement){
          const tag=current.tagName.toLowerCase(),siblings=[...current.parentElement.children].filter(child=>child.tagName===current.tagName);
          parts.unshift(siblings.length>1 ? tag+':nth-of-type('+(siblings.indexOf(current)+1)+')' : tag);
          if(current.parentElement===root){selector=':scope > '+parts.join(' > ');break;}
        }
      }
      if(!selector || selector.length>1000) return {error:'UNSAFE_CONTENT_MEDIA'};
      media.push({kind:node.tagName==='IMG' ? 'image' : 'video',selector});
    }
    if(!text && !media.length){
      if(incomplete && mediaNodes.length) return {incomplete:true,value:null};
      return {error:'REQUIRED_FIELD_MISSING'};
    }
    return {incomplete,value:{kind:text ? media.length ? 'mixed' : 'text' : 'media',text,media:media.slice(0,field.max_media ?? 4),media_truncated:media.length>(field.max_media ?? 4)}};
  };
  return elements.map((element, index) => {
    const rect = element.getBoundingClientRect();
    const x = Math.max(0, Math.min(innerWidth - 1, (Math.max(0, rect.left) + Math.min(innerWidth, rect.right)) / 2));
    const y = Math.max(0, Math.min(innerHeight - 1, (Math.max(0, rect.top) + Math.min(innerHeight, rect.bottom)) / 2));
    const hit = document.elementFromPoint(x, y);
    const searchDescription = [element.getAttribute('type'), element.id, element.getAttribute('name'), element.getAttribute('aria-label'),
      element.getAttribute('placeholder'), element.getAttribute('title'),
      element.id ? document.querySelector(`label[for="${CSS.escape(element.id)}"]`)?.textContent : ''].filter(Boolean).join(' ');
    const form = element.form || element.closest('form');
    const searchForm = form && (form.getAttribute('method') || 'get').toLowerCase() === 'get' &&
      (/search|query|搜索|查询|检索/i.test([form.getAttribute('action'), form.getAttribute('role')].join(' ')) ||
        [...form.querySelectorAll('button,input[type=submit]')].some(button => /search|搜索|查询|检索/i.test([button.textContent, button.getAttribute('aria-label'), button.getAttribute('value')].join(' '))));
    const searchInput = element.matches('input[type=text],input[type=search],input:not([type]),textarea') && !sensitive(element) &&
      !/comment|reply|message|私信|评论|回复|发言|留言|发送/i.test(searchDescription) &&
      (!form || (form.getAttribute('method') || 'get').toLowerCase() === 'get') &&
      (/search|query|keyword|搜索|查询|检索/i.test(searchDescription) || Boolean(searchForm));
    const state = { index, tag: element.tagName.toLowerCase(), role:element.getAttribute('role'), sensitive: sensitive(element), forbidden: element.matches(excluded), search_input: searchInput,
      stable_label:searchInput ? stableFieldLabel(element) : '',
      readonly_root: !sensitive(element) && !element.matches(`${excluded},button,form`) && !element.closest('form'),
      visible: visible(element), in_viewport: viewport(element), unobscured: Boolean(hit && (hit === element || element.contains(hit))),
      fully_in_viewport:fullyViewport(element),
      busy:element.closest('[aria-busy="true"]')!==null || [...element.querySelectorAll('[aria-busy="true"],[role="progressbar"]')].some(visible),
      text: textOf(element), href: hrefOf(element),
      label: clean([element.textContent, element.getAttribute('aria-label'), element.getAttribute('title')].filter(Boolean).join(' ')),
      form_method: element.closest('form')?.getAttribute('method') || 'get' };
    if(nativeProfile){
      const role=element.getAttribute('role'),editable=element.isContentEditable || Boolean(element.closest('[contenteditable]')?.isContentEditable);
      const inForm=Boolean(element.closest('form'));
      const interactiveAncestor=Boolean(element.parentElement?.closest('button,a,[role="button"],[role="link"],[role="checkbox"],[role="radio"],[role="switch"],[role="menuitem"]'));
      state.native_context={
        search_input:searchInput && !editable && (!form || (form.getAttribute('method') || 'get').toLowerCase()==='get') &&
          ['search-input-in-feeds','search-input-ai'].includes(element.id) && !interactiveAncestor && [null,'searchbox','textbox','combobox'].includes(role),
        note_link:element instanceof HTMLAnchorElement && !inForm && !editable && !interactiveAncestor && [null,'link'].includes(role) &&
          !element.hasAttribute('download') && ['', '_self'].includes(element.getAttribute('target') || ''),
        read_root:state.readonly_root && !editable && !['a','body','html'].includes(state.tag) &&
          !['button','link','checkbox','radio','switch','combobox','textbox','menuitem'].includes(role) && !interactiveAncestor,
      };
      if(navigationProfile){
        // Fixed worker metadata only. Caller input cannot assert an anchor is
        // a profile/navigation link, and editable/nested controls stay out.
        const safeAnchor=element instanceof HTMLAnchorElement && !inForm && !editable && !interactiveAncestor && [null,'link'].includes(role) &&
          !element.hasAttribute('download') && ['', '_self','_blank'].includes(element.getAttribute('target') || '');
        let destination=null;
        try{
          const url=new URL(element.href);
          if(url.origin===origin && !url.username && !url.password && !url.port) destination=url;
        }catch{}
        state.native_context.note_link=Boolean(safeAnchor && destination && /^\/(?:explore|search_result)\/[a-fA-F0-9]{24}$/.test(destination.pathname));
        state.native_context.profile_link=Boolean(safeAnchor && destination && /^\/user\/profile\/[a-fA-F0-9]{24}$/.test(destination.pathname));
        state.native_context.navigation_link=Boolean(safeAnchor && destination && ['/explore','/search_result','/search_result_ai','/notification'].includes(destination.pathname));
      }
    }
    if (target) state.match_value = target.field === 'text' ? state.text : target.field === 'href' ? state.href : element.getAttribute(target.attribute);
    if (untilSelector) {
      const matches=[...element.querySelectorAll(untilSelector)];
      state.until={count:matches.length,complete_count:0};
      if(matches.length>200) state.until.error='READ_LIMIT';
      else if(matches.some(child=>sensitive(child) || child.matches(`${excluded},button,form`) || child.closest('form'))) state.until.error='SENSITIVE_OUTPUT';
      else state.until.complete_count=matches.filter(child=>fullyViewport(child,element)).length;
    }
    if (fields) {
      state.values = Object.create(null);
      for (const field of fields) {
        const matches = field.selector ? Array.from(element.querySelectorAll(field.selector)) : [element];
        if (matches.length > 1) { state.error = 'NON_UNIQUE_FIELD'; break; }
        const child = matches[0];
        let value = null;
        if (child && (child.matches(excluded) || sensitive(child))) { state.error = 'SENSITIVE_OUTPUT'; break; }
        const inView=child && viewport(child);
        const actualVisible=child && visible(child);
        if(field.source==='content'){
          if(!child || !actualVisible) {state.error='REQUIRED_FIELD_MISSING';break;}
          if(child.matches('button,form') || child.closest('form')) {state.error='SENSITIVE_OUTPUT';break;}
          const content=contentOf(child,field,element);
          if(content.error){state.error=content.error;break;}
          if(content.incomplete) state.incomplete_fields=true;
          state.values[field.name]=content.value;
          continue;
        }
        if (child && actualVisible && (inView || (completeOnly && field.required))) value = field.source === 'text' ? textOf(child) : field.source === 'href' ? hrefOf(child) : child.getAttribute(field.attribute);
        if (value && typeof value === 'object') { state.error = value.error; break; }
        if (field.required && (value === null || clean(value) === '')) { state.error = 'REQUIRED_FIELD_MISSING'; break; }
        if (completeOnly && field.required && actualVisible && !fullyViewport(child)) {
          state.incomplete_fields=true;
          state.values[field.name]=null;
          continue;
        }
        if (!inView) value=null;
        state.values[field.name] = value === null ? null : clean(value);
      }
    }
    return state;
  });
}

async function inspectLocator(session, selector, params) {
  // CSS is validated before the locator is constructed so Playwright's other
  // selector engines cannot be reached through this interface.
  return session.page.locator(selector).evaluateAll(inspectElements, {
    nativeProfile:isNativeUiProfile(session.executionProfile),navigationProfile:session.executionProfile===NAVIGATION_UI_PROFILE,
    origin: session.origin, target: params.target, fields: params.kind === 'extract' ? params.fields : undefined,
    completeOnly:params.complete_only===true,untilSelector:params.kind==='scroll' ? params.until_selector : undefined,
  });
}

function resolveTarget(states, target) {
  if (!target) return states;
  if (typeof target.value !== 'string' || !target.value.trim()) throw new WorkerError('动态目标缺少实际匹配值', 'MISSING_PARAMETER');
  const matches = states.filter(state => typeof state.match_value === 'string' && state.match_value === target.value.trim());
  if (matches.length !== 1) throw new WorkerError(`动态目标当前匹配 ${matches.length} 个对象，必须唯一核对`, 'NON_UNIQUE_TARGET');
  return matches;
}

function requireOperable(state, { viewport = true, obstruction = false, data = false } = {}) {
  if (state.sensitive || (data && state.forbidden)) throw new WorkerError('不能操作或读取敏感元素、脚本及表单值', 'SENSITIVE_OUTPUT');
  if (!state.visible || (viewport && !state.in_viewport)) throw new WorkerError('目标当前不可见或不在视口，请先显式滚动并重新采集', 'TARGET_NOT_IN_VIEWPORT');
  if (obstruction && !state.unobscured) throw new WorkerError('目标被其他元素遮挡，不能执行操作', 'TARGET_OBSCURED');
}

function renderExtractValue(field,value){
  if(value===null) return null;
  if(field?.source==='content') return {kind:value.kind,text:value.text===null ? null : redactText(value.text),media:value.media.map(item=>({...item})),media_truncated:value.media_truncated};
  return field?.source==='href' ? redactUrl(value) : redactText(value);
}

function selectExtractRows(states, params, { completeRows = false } = {}) {
  if(states.some(state=>state.row_limit)) throw new WorkerError('单次最多检查 500 个候选对象，请缩小范围','READ_LIMIT');
  const visibleStates=states.filter(state=>state.visible && state.in_viewport),selected=[];
  let skippedIncomplete=0;
  for(const state of visibleStates){
    if(selected.length>=params.limit) break;
    requireOperable(state,{data:true});
    if(params.row_selector && state.readonly_root!==true) throw new WorkerError('容器内行不能属于交互或表单区域','SENSITIVE_OUTPUT');
    if(state.error) throw new WorkerError(`结构化字段读取失败：${state.error}`,state.error);
    if(params.complete_only===true && (state.incomplete_fields || (completeRows && !state.fully_in_viewport))){skippedIncomplete+=1;continue;}
    selected.push(state);
  }
  const items=selected.map(state=>Object.fromEntries(Object.entries(state.values).map(([key,value])=>
    [key,renderExtractValue(params.fields.find(field=>field.name===key),value)])));
  return {items,selected,visibleStates,skippedIncomplete,truncated:states.length>selected.length || items.some(item=>params.fields.some(field=>field.source==='content' && item[field.name]?.media_truncated))};
}

async function extractInContainer(session, params, { observed, currentObserved, enableReadonlyPolicy, trace, initialBlockedWrites, noteBinding, batchBudgetMs=15_000 }) {
  const page=session.page,sourceUrl=page.url(),rootLocator=page.locator(params.selector);
  if(!observed || observed.sensitive || observed.unique!==true || !currentObserved || currentObserved.unique!==true || currentObserved.tag!==observed.tag || await rootLocator.count()!==1) {
    throw new WorkerError('容器提取必须使用最近观察到且当前仍唯一的普通容器','UNOBSERVED_CURRENT_SELECTOR');
  }
  const root=await rootLocator.elementHandle({timeout:TIMEOUT});
  const scrollSelector=params.batch?.scroll_selector;
  let scrollRoot;
  if(scrollSelector){
    const scrollObserved=trace.before.elements.find(element=>element.selector===scrollSelector);
    const currentScroll=currentObserved.selector===scrollSelector ? currentObserved : await describeCurrentSelector(page,scrollSelector,scrollObserved);
    if(!scrollObserved || scrollObserved.sensitive || scrollObserved.unique!==true || !scrollObserved.scroll_y || !currentScroll || currentScroll.unique!==true || !currentScroll.scroll_y || await page.locator(scrollSelector).count()!==1) {
      throw new WorkerError('批次滚动根必须为最近观察到且当前唯一的普通容器','UNOBSERVED_CURRENT_SELECTOR');
    }
    scrollRoot=await page.locator(scrollSelector).elementHandle({timeout:TIMEOUT});
  }
  const rootState=async()=>{
    requireBoundNotePage(session,noteBinding);
    if(session.page!==page || page.isClosed() || page.url()!==sourceUrl) throw new WorkerError('批次读取来源已变化，停止混合不同来源','SOURCE_CHANGED');
    sessionFor(session.taskId);
    requireOrigin(session,page.url());
    if(!root || !await root.evaluate((element,selector)=>element.isConnected && document.querySelectorAll(selector).length===1 && document.querySelector(selector)===element,params.selector)) {
      throw new WorkerError('读取容器对象已替换，必须重新观察','STALE_TARGET');
    }
    const states=await root.evaluate(inspectElements,{origin:session.origin,nativeProfile:isNativeUiProfile(session.executionProfile)});
    requireOperable(states[0],{data:true});
    if(states[0].readonly_root!==true) throw new WorkerError('读取容器不能是敏感、交互或表单区域','SENSITIVE_OUTPUT');
    if(isNativeUiProfile(session.executionProfile) && !nativeReadRootsValid(states)) throw new WorkerError('新模式不读取可交互或可编辑区域','SENSITIVE_OUTPUT');
    if(scrollRoot){
      const stable=await scrollRoot.evaluate((element,{selector,rootSelector,rowSelector})=>{
        const container=document.querySelector(rootSelector),matches=document.querySelectorAll(selector),rows=container?.querySelectorAll(rowSelector);
        return element.isConnected && matches.length===1 && matches[0]===element && container?.contains(element) && rows.length<=500 && [...rows].every(row=>element.contains(row));
      },{selector:scrollSelector,rootSelector:params.selector,rowSelector:params.row_selector});
      if(!stable) throw new WorkerError('批次滚动容器或行的所属范围已变化','SOURCE_CHANGED');
      const scrolling=await scrollRoot.evaluate(inspectElements,{origin:session.origin,nativeProfile:isNativeUiProfile(session.executionProfile)});
      requireOperable(scrolling[0],{data:true});
      if(scrolling[0].readonly_root!==true) throw new WorkerError('批次滚动根不能是敏感、交互或表单区域','SENSITIVE_OUTPUT');
      if(isNativeUiProfile(session.executionProfile) && !nativeReadRootsValid(scrolling)) throw new WorkerError('新模式不滚动可交互或可编辑区域','SENSITIVE_OUTPUT');
      if(!await scrollRoot.evaluate(element=>/(?:auto|scroll)/.test(getComputedStyle(element).overflowY) && element.clientHeight>0)) {
        throw new WorkerError('批次滚动根不再是已观察的纵向滚动容器','STALE_TARGET');
      }
    }
    return states[0];
  };
  const inspectRows=()=>root.evaluate(inspectElements,{origin:session.origin,rowSelector:params.row_selector,fields:params.fields,completeOnly:params.complete_only===true});
  const guardRequests=()=>{
    if(session.blockedWrites>initialBlockedWrites) throw new WorkerError('页面尝试产生写请求，已阻止并停止本次只读步骤','WRITE_REQUEST_BLOCKED');
  };
  const initialRoot=await rootState();
  enableReadonlyPolicy([initialRoot]);
  if(params.batch){
    const startedMs=Date.now(),policyEnd=session.platformRequestPolicy?.expiresAt;
    const budgetMs=Math.max(1,Math.min(batchBudgetMs,15_000,Number.isFinite(policyEnd) ? policyEnd-startedMs : 15_000));
    const reserve=Math.min(2_000,Math.max(1,Math.floor(budgetMs/4)));
    const deadline=startedMs+budgetMs-reserve,items=[],seen=new Map();
    let duplicateCount=0,skippedIncomplete=0,stopReason='batch_budget';
    let committedBatches=0;
    trace.batch_evidence=[];
    const output=reason=>({items:structuredClone(items),count:items.length,truncated:true,source_url:noteBinding?.opened ? noteBinding.source_url : redactUrl(sourceUrl),
      coverage:!items.length ? 'empty' : items.length===params.limit ? 'limit_reached' : 'bounded',skipped_incomplete_count:skippedIncomplete,
      batch_summary:{batches_read:committedBatches,duplicates_removed:duplicateCount,stop_reason:reason}});
    return withBatchDeadline(async control=>{
    for(let index=1;index<=params.batch.max_batches;index+=1){
      if(index>1 && Date.now()>=deadline){stopReason='time_budget';break;}
      control.check();
      await rootState();
      await refreshLoginDetection(session);
      sessionFor(session.taskId);
      const batchStates=await inspectRows();
      const batch=selectExtractRows(batchStates,{...params,limit:100},{completeRows:true});
      control.check();
      let added=0,duplicates=0;
      const stagedItems=[...items],stagedSeen=new Map(seen);
      let conflict=false;
      for(const item of batch.items){
        const id=item[params.batch.dedupe_field];
        if(typeof id!=='string' || !id.trim() || id.includes('[已隐藏]') || id.includes('[手机号已隐藏]')) throw new WorkerError('批次业务标识为空或不适合稳定去重','UNSAFE_DEDUPE_ID');
        if(stagedSeen.has(id)){
          duplicates+=1;
          if(JSON.stringify(stagedSeen.get(id))!==JSON.stringify(item)) conflict=true;
        }else if(stagedItems.length<params.limit){stagedSeen.set(id,item);stagedItems.push(item);added+=1;}
      }
      control.check();
      trace.phase='batch_capture';
      const snapshot=await captureSession(session,`有界读取第 ${index} 批`);
      trace.batch_evidence.push({batch_index:index,added_count:added,duplicate_count:duplicates,capture:snapshot});
      control.check();
      trace.phase='execute';
      await rootState();
      await refreshLoginDetection(session);
      sessionFor(session.taskId);
      guardRequests();
      control.check();
      if(conflict) throw new WorkerError('同一业务标识在批次间出现不同字段值，停止合并','DUPLICATE_ID_CONFLICT');
      items.splice(0,items.length,...stagedItems);seen.clear();for(const [id,item] of stagedSeen)seen.set(id,item);
      duplicateCount+=duplicates;skippedIncomplete+=batch.skippedIncomplete;committedBatches+=1;
      trace.batch_partial_result=output('time_budget');
      if(items.length>=params.limit){stopReason='limit_reached';break;}
      if(Date.now()>=deadline){stopReason='time_budget';break;}
      const boundary=await scrollRoot.evaluate(element=>element.scrollTop+element.clientHeight>=element.scrollHeight-1);
      if(boundary){
        const previousHeight=await scrollRoot.evaluate(element=>element.scrollHeight),pollEnd=Math.min(deadline,Date.now()+1_000);
        const fingerprint=states=>JSON.stringify(states.map(state=>({index:state.index,values:state.values,visible:state.in_viewport})));
        const initialRows=fingerprint(batchStates);
        let rowsChanged=false;
        while(Date.now()<pollEnd){
          await page.waitForTimeout(Math.min(100,pollEnd-Date.now()));
          await rootState();
          guardRequests();
          control.check();
          rowsChanged=fingerprint(await inspectRows())!==initialRows;
          if(rowsChanged || await scrollRoot.evaluate(element=>element.scrollHeight)!==previousHeight) break;
        }
        if(rowsChanged && index<params.batch.max_batches) continue;
        if(await scrollRoot.evaluate(element=>element.scrollTop+element.clientHeight>=element.scrollHeight-1)) {stopReason='boundary';break;}
      }
      if(index===params.batch.max_batches) break;
      await rootState();
      control.check();
      await scrollRoot.evaluate((element,pixels)=>element.scrollBy({top:pixels,behavior:'instant'}),params.batch.pixels);
      await page.waitForTimeout(80);
      guardRequests();
    }
    return output(stopReason);
    },{budgetMs,startedMs,cleanupReserveMs:reserve,onTimeout:()=>{
      trace.batch_timeout=true;
      trace.batch_request_blocked=session.blockedWrites>initialBlockedWrites;
      session.closed=true;session.ready=false;session.lastCapture=null;
      endPlatformRequestPolicy(session.platformRequestPolicy);
      session.platformRequestPolicy=null;session.platformRequestPage=null;session.automating=false;
      const closeStart=performance.now();
      session.context.once('close',()=>{trace.batch_context_closed=true;});
      return closeContext(session).finally(()=>{trace.batch_close_ms=Math.max(0,Math.round(performance.now()-closeStart));});
    }});
  }
  const rows=await inspectRows();
  if(rows.length===0 && params.allow_empty===true){
    const proof=async()=>{
      const state=await rootState();
      await refreshLoginDetection(session);
      sessionFor(session.taskId);
      if(state.busy || !state.fully_in_viewport) throw new WorkerError('空态容器仍忙碌或未完整可见','EMPTY_STATE_UNCONFIRMED');
      if((await inspectRows()).length!==0) throw new WorkerError('行集合已变化，不能确认空态','EMPTY_STATE_UNCONFIRMED');
      const markers=await root.evaluate(inspectElements,{origin:session.origin,rowSelector:params.empty_state.selector});
      if(markers.length!==1 || markers[0].readonly_root!==true || !markers[0].fully_in_viewport || markers[0].busy || markers[0].text!==params.empty_state.text.trim()) {
        throw new WorkerError('未观察到唯一、完整可见且文本精确一致的普通空态','EMPTY_STATE_UNCONFIRMED');
      }
      if(redactText(markers[0].text)!==markers[0].text) throw new WorkerError('空态证据不能包含敏感信息','SENSITIVE_OUTPUT');
    };
    await proof();
    await page.waitForTimeout(180);
    await proof();
    guardRequests();
    return {items:[],count:0,truncated:false,source_url:redactUrl(sourceUrl),coverage:'empty',
      ...(params.complete_only===true ? {skipped_incomplete_count:0} : {}),
      empty_state:{confirmed:true,selector:params.empty_state.selector,text:params.empty_state.text.trim()}};
  }
  const selection=selectExtractRows(rows,params);
  return {items:selection.items,count:selection.items.length,truncated:selection.truncated,source_url:redactUrl(sourceUrl),
    coverage:!selection.items.length ? 'empty' : selection.truncated && selection.items.length===params.limit ? 'limit_reached' : 'bounded',
    ...(params.complete_only===true ? {skipped_incomplete_count:selection.skippedIncomplete} : {})};
}

const seekStopReason=code=>({SCROLL_BOUNDARY_BEFORE_TARGET:'boundary',SCROLL_BUDGET_EXHAUSTED:'scroll_budget',SCROLL_TARGET_TIMEOUT:'time_budget',NON_UNIQUE_TARGET:'ambiguous',TARGET_OBSCURED:'obscured',STALE_TARGET:'target_changed',UNOBSERVED_CURRENT_SELECTOR:'target_changed',SCROLL_SOURCE_CHANGED:'source_changed',SENSITIVE_OUTPUT:'unsafe_target',UNSAFE_OUTPUT:'unsafe_target',WRITE_ACTION_BLOCKED:'unsafe_target',ACTION_MISMATCH:'unsafe_target',READ_LIMIT:'unsafe_target',NOTE_BINDING_MISMATCH:'binding_mismatch',WRITE_REQUEST_BLOCKED:'blocked_request'}[code] || 'session_unavailable');

export const snapshotSeekResults=results=>results.map(item=>({...item,movements:item.movements.map(movement=>({...movement}))}));

const validViewport=value=>Boolean(value && Number.isFinite(value.width) && value.width>0 && Number.isFinite(value.height) && value.height>0 &&
  Number.isFinite(value.scroll_x) && Number.isFinite(value.scroll_y) && value.scroll_y>=0);

async function seekScroll(session,params,{observed,currentObserved,observedViewport,currentViewport,trace,enableReadonlyPolicy,initialBlockedWrites,noteBinding}) {
  const page=session.page,source=page.url(),rootLocator=page.locator(params.selector),deadline=Date.now()+params.timeout_ms;
  const viewport=params.scroll_scope==='viewport';
  const summary=trace.seek_result={scrolls:0,movements:[],target_reached:false,stop_reason:'time_budget'};
  if(!observed || observed.sensitive || observed.unique!==true || !currentObserved || currentObserved.sensitive || currentObserved.unique!==true || currentObserved.tag!==observed.tag ||
    ['html','body'].includes(currentObserved.tag) || (viewport ? observed.kind!=='read' || currentObserved.kind!=='read' || !validViewport(observedViewport) || !validViewport(currentViewport) :
      typeof observed.scroll_y?.can_scroll!=='boolean' || typeof currentObserved.scroll_y?.can_scroll!=='boolean')) {
    throw new WorkerError('有界目标滚动必须使用已观察的唯一普通容器及对应滚动元信息','UNOBSERVED_CURRENT_SELECTOR');
  }
  if(typeof params.until_target.value!=='string' || !params.until_target.value.trim()) throw new WorkerError('有界目标尚未提供实际匹配值','MISSING_PARAMETER');
  const root=await rootLocator.elementHandle({timeout:TIMEOUT});
  if(!root) throw new WorkerError('滚动容器已离开页面','STALE_TARGET');
  const scroller=viewport ? (await page.evaluateHandle(()=>document.scrollingElement)).asElement() : null;
  if(viewport && !scroller) throw new WorkerError('页面没有可固定的实际视口滚动对象','ACTION_MISMATCH');
  const checkViewport=async()=>{
    const valid=await scroller.evaluate(element=>element.isConnected && element.ownerDocument===document && document.scrollingElement===element &&
      (element===document.documentElement || element===document.body) && Number.isFinite(innerWidth) && innerWidth>0 && Number.isFinite(innerHeight) && innerHeight>0 &&
      Number.isFinite(scrollX) && Number.isFinite(scrollY) && scrollY>=0 && Number.isFinite(element.scrollTop) && element.scrollTop>=0 &&
      Number.isFinite(element.scrollHeight) && Number.isFinite(element.clientHeight) && element.clientHeight>0 && element.scrollHeight>=element.clientHeight);
    if(!valid) throw new WorkerError('视口滚动对象或实际元信息已变化','STALE_TARGET');
  };
  const check=async()=>{
    if(session.page!==page || page.url()!==source) throw new WorkerError('有界滚动过程中页面来源已变化','SCROLL_SOURCE_CHANGED');
    await refreshLoginDetection(session);
    sessionFor(session.taskId);
    requireBoundNotePage(session,noteBinding);
    if(session.blockedWrites>initialBlockedWrites) throw new WorkerError('页面尝试产生未知写请求，停止本次有界定位','WRITE_REQUEST_BLOCKED');
    const same=await root.evaluate((element,selector)=>element.isConnected && document.querySelectorAll(selector).length===1 && document.querySelector(selector)===element,params.selector);
    if(!same) throw new WorkerError('滚动容器对象已经变化','STALE_TARGET');
    if(viewport) await checkViewport();
    const roots=await root.evaluate(inspectElements,{origin:session.origin,nativeProfile:isNativeUiProfile(session.executionProfile)});
    if(roots.length!==1 || roots[0].readonly_root!==true) throw new WorkerError('滚动根不是普通读取区域','SENSITIVE_OUTPUT');
    if(isNativeUiProfile(session.executionProfile) && !nativeReadRootsValid(roots)) throw new WorkerError('新模式不滚动可交互或可编辑区域','SENSITIVE_OUTPUT');
    requireOperable(roots[0],{data:true});
    if(!viewport && !await root.evaluate(element=>/^(?:auto|scroll)$/.test(getComputedStyle(element).overflowY))) throw new WorkerError('有界定位必须使用实际滚动容器','ACTION_MISMATCH');
    enableReadonlyPolicy(roots);
    const candidates=await root.evaluate(inspectElements,{origin:session.origin,rowSelector:params.until_target.selector,target:params.until_target});
    if(candidates.some(state=>state.row_limit)) throw new WorkerError('有界目标候选超过500个','READ_LIMIT');
    const matches=candidates.filter(state=>typeof state.match_value==='string' && state.match_value===params.until_target.value.trim());
    if(matches.length>1) throw new WorkerError('有界目标当前存在多个精确匹配，停止定位','NON_UNIQUE_TARGET');
    if(!matches.length) return false;
    const target=matches[0];
    if(target.sensitive || target.forbidden) throw new WorkerError('有界目标不是普通可操作元素','SENSITIVE_OUTPUT');
    if(!['a','button'].includes(target.tag) && target.role!=='button') throw new WorkerError('有界目标不是链接或读取按钮','ACTION_MISMATCH');
    if(target.href && typeof target.href!=='string') throw new WorkerError('有界目标来源不是允许的同站链接','UNSAFE_OUTPUT');
    if(DANGEROUS.test(target.label) || DANGEROUS.test(target.href || '') || (target.tag!=='a' && (!READ_ONLY_BUTTON.test(target.label) || target.form_method.toLowerCase()!=='get'))) {
      throw new WorkerError('有界定位仅支持普通同站链接或明确读取按钮','WRITE_ACTION_BLOCKED');
    }
    if(noteBinding){
      const actual=boundNoteSource(target.href,session.origin);
      if(target.tag!=='a' || !actual || actual.note_id!==noteBinding.note_id) throw new WorkerError('有界定位目标与已选笔记编号不一致','NOTE_BINDING_MISMATCH');
    }
    if(!target.fully_in_viewport) return false;
    requireOperable(target,{data:true,obstruction:true});
    return true;
  };
  const poll=async(ms)=>{
    const until=Math.min(deadline,Date.now()+ms);
    do {
      if(await check()) return true;
      if(Date.now()>=until) return false;
      await page.waitForTimeout(Math.min(100,Math.max(1,until-Date.now())));
    }while(true);
  };
  let reached=await check();
  for(let index=0;!reached && index<params.max_scrolls;index+=1){
    if(Date.now()>=deadline) throw new WorkerError('有界定位超过本轮时间预算','SCROLL_TARGET_TIMEOUT');
    // Recheck the pinned root and candidate immediately before each fixed movement.
    if(await check()){reached=true;break;}
    const movement=viewport ? await scroller.evaluate((element,{root,selector,direction,pixels})=>{
      if(!element.isConnected || document.scrollingElement!==element || !root.isConnected || document.querySelectorAll(selector).length!==1 || document.querySelector(selector)!==root) return {error:true};
      const before=element.scrollTop;
      window.scrollBy({top:direction==='down' ? pixels : -pixels,behavior:'instant'});
      return {before,after:element.scrollTop,scroll_height:element.scrollHeight,client_height:element.clientHeight};
    },{root,selector:params.selector,direction:params.direction,pixels:params.pixels}) : await root.evaluate((element,{direction,pixels})=>{
      const before=element.scrollTop;
      element.scrollBy({top:direction==='down' ? pixels : -pixels,behavior:'instant'});
      return {before,after:element.scrollTop,scroll_height:element.scrollHeight,client_height:element.clientHeight};
    },params);
    if(movement.error) throw new WorkerError('滚动前视口或普通目标根已经变化','STALE_TARGET');
    summary.movements.push(movement);summary.scrolls=summary.movements.length;
    await page.waitForTimeout(Math.min(80,Math.max(1,deadline-Date.now())));
    reached=await check();
    if(!reached && movement.before===movement.after){
      reached=await poll(1000);
      if(!reached) throw new WorkerError('已到滚动边界，限定等待后目标仍未完整可操作','SCROLL_BOUNDARY_BEFORE_TARGET');
    }
  }
  if(!reached) reached=await poll(1000);
  if(!reached) throw new WorkerError('有界定位尚未找到完整目标',Date.now()>=deadline ? 'SCROLL_TARGET_TIMEOUT' : 'SCROLL_BUDGET_EXHAUSTED');
  summary.target_reached=true;summary.stop_reason='target_reached';
  return {direction:params.direction,pixels:params.pixels,requested_max_scrolls:params.max_scrolls,scrolls:summary.scrolls,movements:summary.movements,
    brought_into_view:false,target_reached:true,stop_reason:'target_reached',timeout_ms:params.timeout_ms,source_url:redactUrl(page.url())};
}

// Preflight the already existing policy before a wait can enable automation.
// A missing observed collection is a learning precondition, not permission to
// carry search authority into another step or to widen network exceptions.
export function preflightReadonlyWait(context) {
  if(context.kind!=='wait' || context.sessionOrigin!=='https://www.xiaohongshu.com') return null;
  if(Array.isArray(context.actualRoots) && context.actualRoots.some(root=>root?.sensitive || root?.forbidden)) {
    throw new WorkerError('不能等待敏感元素或表单区域','SENSITIVE_OUTPUT');
  }
  const policy=beginReadonlyRequestPolicy(context);
  if(!policy) throw new WorkerError('等待目标尚未满足已观察普通根与只读策略前置条件，请先观察并学习加载过渡','READONLY_WAIT_NOT_READY');
  return policy;
}

async function prepareScopedWait(session,params,previous,noteBinding) {
  const page=session.page,source=page.url(),selector=params.wait_scope;
  const observed=previous.elements.find(element=>element.selector===selector);
  if(!observed || observed.kind!=='read' || observed.unique!==true || observed.sensitive || !observed.in_viewport || /^(?:body|html)$/i.test(observed.tag || '') ||
      await page.locator(selector).count()!==1) throw new WorkerError('范围等待须使用最新观察中唯一可见的普通容器','UNOBSERVED_CURRENT_SELECTOR');
  const current=await describeCurrentSelector(page,selector,observed);
  if(!current || current.unique!==true || current.kind!=='read' || current.tag!==observed.tag) throw new WorkerError('范围等待根已变化，请重新观察','UNOBSERVED_CURRENT_SELECTOR');
  const root=await page.locator(selector).elementHandle({timeout:TIMEOUT});
  const check=async()=>{
    sessionFor(session.taskId);requireBoundNotePage(session,noteBinding);
    if(session.page!==page || page.isClosed() || page.url()!==source) throw new WorkerError('范围等待页面来源已变化','SOURCE_CHANGED');
    if(!root || !await root.evaluate((element,css)=>element.isConnected && document.querySelectorAll(css).length===1 && document.querySelector(css)===element,selector)) {
      throw new WorkerError('范围等待的固定容器已替换','SOURCE_CHANGED');
    }
    const states=await root.evaluate(inspectElements,{origin:session.origin,fixedRootSelector:selector,fixedSourceUrl:source,nativeProfile:isNativeUiProfile(session.executionProfile)});
    if(states.some(state=>state.scope_changed) || session.page!==page || page.url()!==source) throw new WorkerError('范围等待的固定容器或来源已变化','SOURCE_CHANGED');
    requireOperable(states[0],{data:true});
    if(states[0].readonly_root!==true) throw new WorkerError('范围等待根不能是表单或交互区域','SENSITIVE_OUTPUT');
    if(isNativeUiProfile(session.executionProfile) && !nativeReadRootsValid(states)) throw new WorkerError('新模式等待根不能是可交互或可编辑区域','SENSITIVE_OUTPUT');
    return states[0];
  };
  await check();
  return {observed,check,async rows(){
    const rows=await root.evaluate(inspectElements,{origin:session.origin,rowSelector:params.selector,fixedRootSelector:selector,fixedSourceUrl:source});
    if(rows.some(row=>row.scope_changed)) throw new WorkerError('范围等待的固定容器或来源已变化','SOURCE_CHANGED');
    if(rows.some(row=>row.row_limit) || rows.length>100) throw new WorkerError('范围等待最多核对100个集合对象','READ_LIMIT');
    if(rows.some(row=>row.sensitive || row.forbidden || row.readonly_root!==true)) throw new WorkerError('范围等待集合包含敏感或交互对象','SENSITIVE_OUTPUT');
    return rows;
  }};
}

async function waitInScope(session,params,scope,{trace,initialBlockedWrites,noteBinding}) {
  const startedMs=Date.now(),policyEnd=session.platformRequestPolicy?.expiresAt;
  const budgetMs=Math.max(1,Math.min(params.timeout_ms,Number.isFinite(policyEnd) ? policyEnd-startedMs : params.timeout_ms));
  const guard=()=>{if(session.blockedWrites>initialBlockedWrites) throw new WorkerError('范围等待期间已阻止未知请求','WRITE_REQUEST_BLOCKED');};
  return withWaitDeadline(async control=>{
    for(;;){
      control.check();await scope.check();
      await refreshLoginDetection(session);sessionFor(session.taskId);
      const rows=await scope.rows();
      await scope.check();guard();control.check();
      if(rows.filter(row=>row.visible && row.in_viewport && !row.busy).length>=params.min_count){
        return {satisfied:true,state:'visible',selector:params.selector,wait_scope:params.wait_scope,min_count:params.min_count,timeout_ms:params.timeout_ms};
      }
      await session.page.waitForTimeout(80);
    }
  },{budgetMs,startedMs,cleanupReserveMs:Math.min(2_000,Math.max(1,Math.floor(budgetMs/4))),onTimeout:()=>{
    trace.wait_timeout=true;trace.wait_request_blocked=session.blockedWrites>initialBlockedWrites;
    session.closed=true;session.ready=false;session.lastCapture=null;
    endPlatformRequestPolicy(session.platformRequestPolicy);
    session.platformRequestPolicy=null;session.platformRequestPage=null;session.automating=false;
    const closeStart=performance.now();
    session.context.once('close',()=>{trace.wait_context_closed=true;});
    return closeContext(session).finally(()=>{trace.wait_close_ms=Math.max(0,Math.round(performance.now()-closeStart));});
  }});
}

async function performActionSession(session, params, { captureBefore = true, trace, noteBinding, batchBudgetMs=15_000 } = {}) {
  if (shuttingDown) throw new WorkerError('学习工作进程正在退出', 'WORKER_CLOSING');
  const kind = params.kind;
  validateAction(params);
  requireBoundNotePage(session,noteBinding);
  const selector = requireString(params.selector, 'selector', 1_000);
  const previous = session.lastCapture;
  if (!previous || previous.url !== redactUrl(session.page.url())) {
    throw new WorkerError('页面已变化或尚未采集，请先重新采集当前页面', 'FRESH_CAPTURE_REQUIRED');
  }
  const observed = previous.elements.find(element => element.selector === selector);
  if (kind === 'wait' && params.state === 'hidden' && selector !== 'body' && !session.observedSelectors.has(selector)) {
    throw new WorkerError('消失等待需要本会话已采集过的普通元素', 'UNOBSERVED_SELECTOR');
  }
  const flexible = ['wait', 'extract'].includes(kind) || Boolean(params.target) || (kind === 'scroll' && selector === 'body');
  if (!flexible && (!observed || observed.sensitive)) throw new WorkerError('定位必须来自最近一次页面采集的可用元素', 'UNOBSERVED_SELECTOR');
  if (kind === 'fill' && observed?.kind !== 'fill') throw new WorkerError('该元素不是可填写的普通输入框', 'ACTION_MISMATCH');
  if (kind === 'press' && (observed?.kind !== 'fill' || !observed.search_input)) throw new WorkerError('Enter 仅适用于已观察的普通搜索输入框，不能提交评论或消息', 'WRITE_ACTION_BLOCKED');
  if (kind === 'click' && !params.target && observed?.kind !== 'click') throw new WorkerError('该元素不是已观察到的链接或按钮', 'ACTION_MISMATCH');
  let locator = session.page.locator(selector);
  const count = params.wait_scope ? 0 : await locator.count();
  if (kind !== 'wait' && ((!count && kind !== 'extract') || (!['read', 'extract'].includes(kind) && !params.target && count !== 1))) {
    throw new WorkerError(`定位当前匹配 ${count} 个元素，操作要求唯一目标`, 'NON_UNIQUE_TARGET');
  }
  if (kind === 'read' && count > 200) throw new WorkerError('单次读取最多 200 个对象，请缩小定位范围', 'READ_LIMIT');
  if (count > 500) throw new WorkerError('单次最多检查 500 个候选对象，请缩小范围', 'READ_LIMIT');
  trace.phase = 'inspect_current';
  const currentObserved = params.wait_scope ? null : await describeCurrentSelector(session.page,selector,observed);
  const currentViewport=kind==='scroll' && params.scroll_scope==='viewport' ? await session.page.evaluate(()=>({width:innerWidth,height:innerHeight,scroll_x:scrollX,scroll_y:scrollY})) : null;
  if (!flexible && !currentObserved) throw new WorkerError('本次页面采集未返回该定位，请重新采集并核对当前控件', 'UNOBSERVED_CURRENT_SELECTOR');
  const searchAction = ['fill','press'].includes(kind) && observed?.search_input===true;
  const sameStableSearch = searchAction && currentObserved?.search_input===true && observed.unique===true && currentObserved.unique===true &&
    currentObserved.tag===observed.tag && typeof observed.stable_label==='string' && observed.stable_label.length>0 &&
    currentObserved.stable_label===observed.stable_label;
  if (!flexible && ((!['read', 'scroll'].includes(kind) && (currentObserved.label !== observed.label || currentObserved.tag !== observed.tag) && !sameStableSearch) ||
      (searchAction && observed.stable_label && !sameStableSearch))) {
    throw new WorkerError('目标语义已变化，请重新采集后确认', 'STALE_TARGET');
  }
  if(captureBefore) trace.phase = 'capture_before';
  const before = trace.before = captureBefore ? await captureSession(session) : previous;
  trace.phase = 'resolve_target';
  requireBoundNotePage(session,noteBinding);
  let states = params.wait_scope ? [] : resolveTarget(await inspectLocator(session, selector, params.row_selector ? {...params,kind:'read'} : params), params.target);
  requireBoundNotePage(session,noteBinding);
  if (searchAction && observed.stable_label && (states.length!==1 || states[0].search_input!==true || states[0].stable_label!==observed.stable_label)) {
    throw new WorkerError('搜索控件的固定语义已变化，请重新采集并核对', 'STALE_TARGET');
  }
  if (params.target) locator = locator.nth(states[0].index);
  let objectHandle;
  let targetResolvedUnique = false;
  if (['fill', 'press', 'click'].includes(kind) || (kind === 'read' && params.target)) {
    // Pin the object itself: resolving an nth locator again during a rerender
    // must never silently redirect a click to a different row.
    objectHandle = await locator.elementHandle({ timeout: TIMEOUT });
    if (!objectHandle) throw new WorkerError('目标对象已离开页面，请重新采集', 'STALE_TARGET');
    const pinned = await objectHandle.evaluate(inspectElements, { origin: session.origin, target: params.target,nativeProfile:isNativeUiProfile(session.executionProfile),navigationProfile:session.executionProfile===NAVIGATION_UI_PROFILE });
    if (params.target) {
      resolveTarget(pinned, params.target);
      targetResolvedUnique = states.length === 1 && pinned.length === 1;
    }
    else if (pinned[0].tag !== states[0].tag || pinned[0].label !== states[0].label ||
        (searchAction && pinned[0].stable_label!==states[0].stable_label)) throw new WorkerError('目标在执行前发生变化', 'STALE_TARGET');
    states = pinned;
  }
  if (['fill', 'press', 'click'].includes(kind)) requireOperable(states[0], { obstruction: true });
  if (kind === 'press' && !states[0].search_input) throw new WorkerError('当前目标已不再是普通搜索输入框', 'WRITE_ACTION_BLOCKED');
  if (kind === 'click' && !['a', 'button'].includes(states[0].tag)) {
    const role = await locator.getAttribute('role');
    if (role !== 'button') throw new WorkerError('动态目标不是链接或按钮', 'ACTION_MISMATCH');
  }
  if (kind === 'extract') states.forEach(state => {
    if (state.sensitive || state.forbidden) throw new WorkerError('结构化行不能是敏感元素、脚本或表单控件', 'SENSITIVE_OUTPUT');
  });
  sessionFor(session.taskId);
  const scopedWait=params.wait_scope ? await prepareScopedWait(session,params,previous,noteBinding) : null;
  const nativeProfile=isNativeUiProfile(session.executionProfile);
  let nativeContext;
  if(nativeProfile){
    const nativeRoots=['fill','press','click'].includes(kind) ? states : scopedWait ? [await scopedWait.check()] :
      await inspectLocator(session,selector,{kind:'read'});
    nativeContext={executionProfile:session.executionProfile,sessionOrigin:session.origin,targetResolvedUnique,pageUrl:session.page.url(),kind,selector,key:params.key,observed,
      actualRoots:nativeRoots,matchCount:params.target ? 1 : count,href:kind==='click' ? states[0]?.href : undefined,
      noteId:noteBinding?.note_id,keyword:kind==='fill' ? params.value : undefined};
    if(kind==='press'){
      // Check the exact ordinary search control before reading its business
      // search value; never inspect arbitrary form inputs for this purpose.
      assertNativeUiAction({...nativeContext,keyword:'ordinary_search_precheck'});
      nativeContext.keyword=await objectHandle.inputValue({timeout:TIMEOUT});
    }
    assertNativeUiAction(nativeContext);
  }
  const initialBlockedWrites = session.blockedWrites;
  const readonlyContext = roots=>({sessionOrigin:session.origin,pageUrl:session.page.url(),kind,selector:params.wait_scope || selector,
    observed:scopedWait?.observed || observed,scrollScope:params.scroll_scope,untilTarget:params.until_target,
    selectorObserved:scopedWait ? true : Boolean(observed && !observed.sensitive) || (kind==='wait' && params.state==='hidden' && session.observedSelectors.has(selector)),actualRoots:roots});
  const enableReadonlyPolicy = roots => {
    if(nativeProfile) assertNativeUiAction({...nativeContext,actualRoots:roots});
    if (session.platformRequestPolicy) return;
    session.platformRequestPolicy = nativeProfile ? beginNativeUiRequestPolicy({...nativeContext,actualRoots:roots}) : beginReadonlyRequestPolicy(readonlyContext(roots));
    if(nativeProfile && !session.platformRequestPolicy) throw new WorkerError('当前动作未满足有界网页操作合同','NATIVE_UI_POLICY_NOT_READY');
    session.platformRequestPage = session.platformRequestPolicy ? session.page : null;
  };
  if(nativeProfile || kind==='wait'){
    // Authorize the already checked action before enabling automation. There
    // must be no interval in which normal page traffic sees a missing policy.
    session.platformRequestPolicy=nativeProfile ? beginNativeUiRequestPolicy(nativeContext) : preflightReadonlyWait(readonlyContext(scopedWait ? [await scopedWait.check()] : states));
    if(nativeProfile && !session.platformRequestPolicy) throw new WorkerError('当前动作未满足有界网页操作合同','NATIVE_UI_POLICY_NOT_READY');
    session.platformRequestPage=session.platformRequestPolicy ? session.page : null;
  }
  session.automating = true;
  let result;
  try {
    trace.phase = 'execute';
    requireBoundNotePage(session,noteBinding);
    if (kind === 'fill') {
      if (typeof params.value !== 'string' || params.value.length > 2_000) throw new WorkerError('填写值必须是最多 2000 字符的文本', 'INVALID_INPUT');
      if (/(?:\+?86[-\s]?)?1[3-9]\d{9}|(?:验证码|密码|password)\s*[:：]/i.test(params.value)) {
        throw new WorkerError('此学习步骤不接受平台手机号、密码或验证码', 'SENSITIVE_INPUT');
      }
      if(!nativeProfile) session.platformRequestPolicy = beginSearchRequestPolicy({ sessionOrigin: session.origin, pageUrl: session.page.url(),
        kind, observed, actual: states[0], matchCount: count });
      session.platformRequestPage = session.platformRequestPolicy ? session.page : null;
      await objectHandle.fill(params.value, { timeout: TIMEOUT });
      result = { filled: true, selector };
    } else if (kind === 'press') {
      if(!nativeProfile) session.platformRequestPolicy = beginSearchRequestPolicy({ sessionOrigin: session.origin, pageUrl: session.page.url(),
        kind, key: params.key, observed, actual: states[0], matchCount: count });
      session.platformRequestPage = session.platformRequestPolicy ? session.page : null;
      await objectHandle.press('Enter', { timeout: TIMEOUT });
      trace.phase = 'settle';
      await settle(session.page);
      await settlePopups(session);
      requireOrigin(session, session.page.url());
      if(nativeProfile){
        const deadline=Date.now()+TIMEOUT;
        while(nativeSearchKeyword(session.page.url())!==nativeContext.keyword.trim()){
          sessionFor(session.taskId);
          if(session.blockedWrites>initialBlockedWrites) throw new WorkerError('搜索过渡期间有请求超出当前动作范围','WRITE_REQUEST_BLOCKED');
          if(Date.now()>=deadline) throw new WorkerError('搜索未在预算内进入对应关键词结果页','SEARCH_TRANSITION_NOT_READY');
          await session.page.waitForTimeout(80);
        }
      }
      result = { pressed: true, key: 'Enter', selector, url: redactUrl(session.page.url()) };
    } else if (kind === 'click') {
      const target = await objectHandle.evaluate(element => ({
        tag: element.tagName.toLowerCase(),
        label: [element.textContent, element.getAttribute('aria-label'), element.getAttribute('title')].filter(Boolean).join(' ').trim(),
        href: element instanceof HTMLAnchorElement ? element.href : '',
        formMethod: element.closest('form')?.getAttribute('method') || 'get',
      }));
      if(nativeProfile){
        const pinned=await objectHandle.evaluate(inspectElements,{origin:session.origin,nativeProfile:true,navigationProfile:session.executionProfile===NAVIGATION_UI_PROFILE});
        assertNativeUiAction({...nativeContext,actualRoots:pinned,href:target.href});
        if(target.href!==nativeContext.href) throw new WorkerError('实际笔记链接在点击前已变化','STALE_TARGET');
      }
      if(noteBinding){
        const actual=target.tag==='a' ? boundNoteSource(target.href,session.origin) : null;
        if(!actual || actual.note_id!==noteBinding.note_id) throw new WorkerError('唯一标题当前链接不是本次已选笔记，未执行点击','NOTE_BINDING_MISMATCH');
        noteBinding.href_checked=true;
      }
      if (DANGEROUS.test(target.label) || DANGEROUS.test(target.href)) {
        throw new WorkerError('首版学习验证不执行关注、私信、发送、提交、支付或删除动作', 'WRITE_ACTION_BLOCKED');
      }
      if (target.tag === 'a' && target.href) {
        const url = httpUrl(target.href);
        requireOrigin(session, url.href);
      } else if (!READ_ONLY_BUTTON.test(target.label) || target.formMethod.toLowerCase() !== 'get') {
        throw new WorkerError('首版仅允许同站点链接或明确的搜索、查询、展开、加载按钮', 'WRITE_ACTION_BLOCKED');
      }
      session.popupPermission = { opener: session.page, expectedUrl: target.tag === 'a' ? target.href : null, adopted: false,
        ...(session.executionProfile===NAVIGATION_UI_PROFILE ? {sourceUrl:session.page.url()} : {}) };
      if(!nativeProfile) session.platformRequestPolicy = beginNoteOpenRequestPolicy({ sessionOrigin: session.origin, pageUrl: session.page.url(), kind,
        observed, actual: states[0], matchCount: targetResolvedUnique ? 1 : count, href: target.href, targetResolvedUnique });
      session.platformRequestPage = session.platformRequestPolicy ? session.page : null;
      await objectHandle.click({ timeout: TIMEOUT });
      trace.phase = 'settle';
      await settle(session.page);
      await settlePopups(session);
      await settle(session.page);
      requireOrigin(session, session.page.url());
      if(noteBinding){noteBinding.opened=true;requireBoundNotePage(session,noteBinding);}
      result = { clicked: true, selector, url: redactUrl(session.page.url()) };
    } else if (kind === 'read') {
      result = states.map(state => {
        requireOperable(state, { data:true, viewport:Boolean(params.target) });
        if (state.href && typeof state.href !== 'string') throw new WorkerError('读取来源不是允许的同源链接', 'UNSAFE_OUTPUT');
        return { text:redactText(state.text || ''), ...(state.href ? {href:redactUrl(state.href)} : {}) };
      });
      enableReadonlyPolicy(states);
    } else if (kind === 'scroll' && params.until_target) {
      result=await seekScroll(session,params,{observed,currentObserved,observedViewport:previous.viewport,currentViewport,trace,enableReadonlyPolicy,initialBlockedWrites,noteBinding});
    } else if (kind === 'scroll') {
      if(params.until_selector && states.some(state=>state.until?.error)) {
        const invalid=states.find(state=>state.until?.error);
        throw new WorkerError('滚动目标不是可读取的普通有界元素',invalid.until.error);
      }
      if (selector !== 'body') {
        requireOperable(states[0], { viewport: false, data: true });
        enableReadonlyPolicy(states);
        await locator.scrollIntoViewIfNeeded({ timeout: TIMEOUT });
      } else enableReadonlyPolicy(states);
      const movements = [];
      const untilReached=async(pollMs=0)=>{
        const deadline=Date.now()+pollMs;
        do {
          const current=await inspectLocator(session,selector,params);
          if(current.length!==1) throw new WorkerError('滚动容器已变化，必须保持唯一','STALE_TARGET');
          if(current[0].readonly_root!==true) throw new WorkerError('滚动容器已变为敏感或表单区域','SENSITIVE_OUTPUT');
          const until=current[0].until;
          if(until?.error) throw new WorkerError('滚动目标不是可读取的普通有界元素',until.error);
          if(until?.complete_count>0) return true;
          if(Date.now()>=deadline) return false;
          await session.page.waitForTimeout(Math.min(100,Math.max(1,deadline-Date.now())));
        } while(true);
      };
      let reached=params.until_selector ? await untilReached() : false;
      for (let index = 0; index < params.max_scrolls && !reached; index += 1) {
        const movement = await locator.evaluate((element, { direction, pixels, pageScroll }) => {
          const root = pageScroll ? document.scrollingElement : element;
          const before = root.scrollTop;
          root.scrollBy({ top: direction === 'down' ? pixels : -pixels, behavior: 'instant' });
          return { before, after: root.scrollTop, scroll_height: root.scrollHeight, client_height: root.clientHeight };
        }, { ...params, pageScroll: selector === 'body' });
        movements.push(movement);
        await session.page.waitForTimeout(80);
        if(params.until_selector) reached=await untilReached();
        if (movement.before === movement.after) {
          if(params.until_selector && !reached) reached=await untilReached(1000);
          if(params.until_selector && !reached) throw new WorkerError('已到滚动边界，限定等待后目标仍未完整可见','SCROLL_BOUNDARY_BEFORE_TARGET');
          break;
        }
      }
      if(params.until_selector && !reached) reached=await untilReached(1000);
      if(params.until_selector && !reached) throw new WorkerError('本次滚动预算已耗尽，目标尚未完整可见','SCROLL_BUDGET_EXHAUSTED');
      result = { direction: params.direction, pixels: params.pixels, requested_max_scrolls: params.max_scrolls,
        scrolls: movements.length, movements, brought_into_view: selector !== 'body' && !states[0].in_viewport,
        ...(params.until_selector ? {until_selector:params.until_selector,until_reached:reached} : {}),
        source_url: redactUrl(session.page.url()) };
    } else if (kind === 'wait' && scopedWait) {
      result=await waitInScope(session,params,scopedWait,{trace,initialBlockedWrites,noteBinding});
    } else if (kind === 'wait') {
      if (states.some(state=>state.sensitive || state.forbidden)) throw new WorkerError('不能观察敏感元素或表单值', 'SENSITIVE_OUTPUT');
      if(params.min_count!==undefined && states.length>100) throw new WorkerError('集合等待最多核对100个候选对象','READ_LIMIT');
      if (params.state!=='hidden' && params.min_count===undefined && states.length>1) throw new WorkerError('条件等待必须定位唯一对象', 'NON_UNIQUE_TARGET');
      enableReadonlyPolicy(states);
      const deadline = Date.now() + params.timeout_ms;
      let satisfied = false;
      do {
        const currentStates = await inspectLocator(session, selector, params);
        if (currentStates.length > 500) throw new WorkerError('等待目标范围过大', 'READ_LIMIT');
        if (currentStates.some(state => state.sensitive || state.forbidden)) throw new WorkerError('不能观察敏感元素或表单值', 'SENSITIVE_OUTPUT');
        if (params.state === 'hidden') satisfied = currentStates.length === 0 || currentStates.every(state => !state.visible);
        else {
          if(params.min_count!==undefined){
            if(currentStates.length>100) throw new WorkerError('集合等待最多核对100个候选对象','READ_LIMIT');
            satisfied=currentStates.filter(state=>state.visible && state.in_viewport).length>=params.min_count;
          }else {
          if (currentStates.length > 1) throw new WorkerError('条件等待必须定位唯一对象', 'NON_UNIQUE_TARGET');
          const state = currentStates[0];
          satisfied = Boolean(state?.visible && (params.state !== 'text' || state.text?.includes(params.text)));
          }
        }
        enableReadonlyPolicy(currentStates);
        if (satisfied) break;
        if (Date.now() >= deadline) throw new WorkerError('条件等待超时，当前页面尚未达到预期状态', 'WAIT_TIMEOUT');
        await session.page.waitForTimeout(Math.min(100, Math.max(1, deadline - Date.now())));
      } while (true);
      result = { satisfied, state: params.state, selector, timeout_ms: params.timeout_ms,
        ...(params.min_count!==undefined ? {min_count:params.min_count} : {}) };
    } else if (kind === 'extract') {
      if(params.row_selector){
        result=await extractInContainer(session,params,{observed,currentObserved,enableReadonlyPolicy,trace,initialBlockedWrites,noteBinding,batchBudgetMs});
      }else {
      const visibleStates = states.filter(state => state.visible && state.in_viewport);
      if (params.target && !visibleStates.length) throw new WorkerError('动态行当前不在视口，请先显式滚动', 'TARGET_NOT_IN_VIEWPORT');
      const selected=[];
      let skippedIncomplete=0;
      for (const state of visibleStates) {
        if(selected.length>=params.limit) break;
        requireOperable(state, { data: true });
        if (state.error) throw new WorkerError(`结构化字段读取失败：${state.error}`, state.error);
        if(params.complete_only===true && state.incomplete_fields){skippedIncomplete+=1;continue;}
        selected.push(state);
      }
      const items = selected.map(state => Object.fromEntries(Object.entries(state.values).map(([key, value]) =>
        [key,renderExtractValue(params.fields.find(field=>field.name===key),value)])));
      enableReadonlyPolicy(selected.length ? selected : visibleStates);
      const truncated = states.length > selected.length || items.some(item=>params.fields.some(field=>field.source==='content' && item[field.name]?.media_truncated));
      result = { items, count: items.length, truncated, source_url: redactUrl(session.page.url()),
        coverage: !items.length ? 'empty' : truncated && items.length === params.limit ? 'limit_reached' : 'bounded',
        ...(params.complete_only===true ? {skipped_incomplete_count:skippedIncomplete} : {}) };
      }
    }
    if(noteBinding?.opened){
      requireBoundNotePage(session,noteBinding);
      if(result && typeof result==='object' && Object.hasOwn(result,'source_url')) result.source_url=noteBinding.source_url;
      if(kind==='extract' && params.output_name==='note_detail'){
        noteBinding.title=typeof result.items?.[0]?.title==='string' ? result.items[0].title : null;
        if(noteBinding.title?.trim()!==noteBinding.note_title) throw new WorkerError('实际读取笔记标题与本次已选标题不一致，停止后续评论读取','NOTE_BINDING_MISMATCH');
      }
    }
    trace.phase = 'settle';
    await session.page.waitForTimeout(120);
    await settlePopups(session);
    requireBoundNotePage(session,noteBinding);
    if(nativeProfile) assertNativeUiResultLocation(nativeContext,session.page.url());
    trace.phase = 'request_guard';
    if (session.blockedWrites > initialBlockedWrites) throw new WorkerError('页面尝试产生写请求，已阻止并停止本次只读步骤', 'WRITE_REQUEST_BLOCKED');
  } finally {
    endPlatformRequestPolicy(session.platformRequestPolicy);
    session.platformRequestPolicy = null;
    session.platformRequestPage = null;
    session.automating = false;
  }
  trace.phase = 'capture_after';
  const after = trace.after = await captureSession(session);
  requireBoundNotePage(session,noteBinding);
  if(nativeProfile) assertNativeUiResultLocation(nativeContext,session.page.url());
  if(scopedWait){
    trace.phase='inspect_current';
    await scopedWait.check();
    const rows=await scopedWait.rows();
    if(rows.filter(row=>row.visible && row.in_viewport && !row.busy).length<params.min_count) {
      throw new WorkerError('等待条件在后置取证期间已变化，请重新观察','WAIT_CONDITION_CHANGED');
    }
  }
  return { result, before, after,...executionMetadata(session.executionProfile),...(trace.batch_evidence ? {batch_evidence:trace.batch_evidence} : {}) };
}

async function actionSession(session, params, options = {}) {
  const trace = actionTrace();
  options.onTrace?.(trace);
  const diagnostics = { phase: 'validate', blocked_requests: [], blocked_request_count: 0 };
  trace.diagnostics=diagnostics;
  session.actionDiagnostics = diagnostics;
  try {
    return await performActionSession(session, params, { ...options, trace });
  } catch (cause) {
    const error = cause instanceof WorkerError || cause instanceof ActionInputError ? cause :
      new WorkerError('浏览器动作未完成，请核对失败阶段与页面证据', 'BROWSER_ERROR');
    if(error.code==='NAVIGATION_BINDING_MISMATCH' && error.navigation_comparison) diagnostics.navigation_comparison=error.navigation_comparison;
    diagnostics.phase = trace.phase;
    if (!shuttingDown && !session.closed && !session.page.isClosed()) {
      // Failed requests may still have changed the page. Keep that actual state
      // without claiming the action completed or replaying it.
      trace.phase='failure_capture';
      trace.after = await captureSession(session, '失败后的实际页面状态').catch(() => null);
    }
    if (trace.before) error.before = trace.before;
    if (trace.after) error.after = trace.after;
    if(trace.batch_evidence) error.batch_evidence=trace.batch_evidence;
    if(trace.batch_context_closed===true || trace.wait_context_closed===true) error.session_closed=true;
    if(trace.batch_request_blocked===true || trace.wait_request_blocked===true) error.error_codes=['WRITE_REQUEST_BLOCKED'];
    if(trace.seek_result){
      error.seek_result={...trace.seek_result,target_reached:false,stop_reason:seekStopReason(error.code)};
    }
    error.diagnostics = structuredClone(diagnostics);
    throw error;
  } finally {
    endPlatformRequestPolicy(session.platformRequestPolicy);
    session.platformRequestPolicy = null;
    session.platformRequestPage = null;
    session.automating = false;
    session.popupPermission = null;
    session.actionDiagnostics = null;
    if (session.page.isClosed() && !session.closed) {
      session.closed = true;
      session.ready = false;
      session.lastCapture = null;
      void closeContext(session);
    }
  }
}

async function action(params) {
  return actionSession(sessionFor(params.task_id), params);
}

async function close(params) {
  const taskId = requireString(params.task_id, 'task_id', 128);
  const session = sessions.get(taskId);
  if (!session) return { closed: true, profile_preserved: true };
  session.closed = true;
  session.ready = false;
  session.lastCapture = null;
  await closeContext(session);
  sessions.delete(taskId);
  if (accountOwners.get(session.accountId) === taskId) accountOwners.delete(session.accountId);
  return { closed: true, profile_preserved: true };
}

async function closeContext(session) {
  if (closingAccounts.has(session.accountId)) return closingAccounts.get(session.accountId);
  const promise = session.context.close().catch(() => {}).finally(() => {
    if (accountOwners.get(session.accountId) === session.taskId) accountOwners.delete(session.accountId);
    closingAccounts.delete(session.accountId);
  });
  closingAccounts.set(session.accountId, promise);
  return promise;
}

const emptyExpectation=value=>value && typeof value==='object' && !Array.isArray(value) && Object.keys(value).length===1 && value.state==='empty';
const nonemptyExpectation=value=>value && typeof value==='object' && !Array.isArray(value) && Object.keys(value).length===1 && value.state==='nonempty';

export function validContentValue(field,value){
  if(!value || typeof value!=='object' || Array.isArray(value) || Object.keys(value).length!==4 || Object.keys(value).some(key=>!['kind','text','media','media_truncated'].includes(key)) ||
    !['text','media','mixed'].includes(value.kind) || (value.text!==null && (typeof value.text!=='string' || !value.text.trim())) ||
    !Array.isArray(value.media) || value.media.length>(field.max_media ?? 4) || typeof value.media_truncated!=='boolean') return false;
  if(value.kind!==(value.text ? value.media.length ? 'mixed' : 'text' : 'media') || (!value.text && !value.media.length) || (value.media_truncated && value.media.length!==(field.max_media ?? 4))) return false;
  const selectors=new Set();
  for(const media of value.media){
    if(!media || typeof media!=='object' || Array.isArray(media) || Object.keys(media).length!==2 || !['image','video'].includes(media.kind) || !Object.hasOwn(media,'selector') || selectors.has(media.selector)) return false;
    try{validateSelector(media.selector,{relative:true});}catch{return false;}
    selectors.add(media.selector);
  }
  return true;
}

// This checks the extraction contract and result structure only. It deliberately
// makes no claim that a title, author or comment matches a business requirement.
export function validNonemptyExtractOutput(step,output){
  if(!step || step.kind!=='extract') return false;
  try {validateAction(step);}catch{return false;}
  if(!output || typeof output!=='object' || Array.isArray(output)) return false;
  const keys=['items','count','truncated','source_url','coverage',...(step.complete_only===true ? ['skipped_incomplete_count'] : []),...(step.batch ? ['batch_summary'] : [])];
  if(Object.keys(output).length!==keys.length || Object.keys(output).some(key=>!keys.includes(key)) || !Array.isArray(output.items) ||
    !Number.isInteger(output.count) || output.count<1 || output.count!==output.items.length || output.count>step.limit || typeof output.truncated!=='boolean' ||
    !['bounded','limit_reached'].includes(output.coverage)) return false;
  try {httpUrl(output.source_url);}catch{return false;}
  if(output.coverage==='limit_reached' && (!output.truncated || output.count!==step.limit)) return false;
  if(step.complete_only===true && (!Number.isInteger(output.skipped_incomplete_count) || output.skipped_incomplete_count<0 || (output.skipped_incomplete_count>0 && !output.truncated))) return false;
  const names=step.fields.map(field=>field.name);
  if(output.items.some(item=>!item || typeof item!=='object' || Array.isArray(item) || Object.keys(item).length!==names.length || Object.keys(item).some(key=>!names.includes(key)) ||
    step.fields.some(field=>field.source==='content' ? !validContentValue(field,item[field.name]) :
      (item[field.name]!==null && typeof item[field.name]!=='string') || (field.required && (typeof item[field.name]!=='string' || !item[field.name].trim()))))) return false;
  if(output.truncated!==true && output.items.some(item=>step.fields.some(field=>field.source==='content' && item[field.name]?.media_truncated))) return false;
  if(step.batch){
    const summary=output.batch_summary;
    if(output.truncated!==true || !summary || typeof summary!=='object' || Array.isArray(summary) || Object.keys(summary).length!==3 ||
      Object.keys(summary).some(key=>!['batches_read','duplicates_removed','stop_reason'].includes(key)) ||
      !Number.isInteger(summary.batches_read) || summary.batches_read<1 || summary.batches_read>step.batch.max_batches ||
      !Number.isInteger(summary.duplicates_removed) || summary.duplicates_removed<0 ||
      !['limit_reached','boundary','batch_budget','time_budget'].includes(summary.stop_reason) ||
      (summary.stop_reason==='limit_reached' && output.count!==step.limit)) return false;
    const identities=output.items.map(item=>item[step.batch.dedupe_field]);
    if(identities.some(value=>typeof value!=='string' || !value.trim()) || new Set(identities).size!==identities.length) return false;
  }
  return true;
}

function assertExpected(expected, outputs, steps = []) {
  if (!expected || typeof expected !== 'object' || Array.isArray(expected) || !Object.keys(expected).length) {
    throw new WorkerError('实际试跑必须提供至少一个明确的输出预期', 'EXPECTED_OUTPUT_REQUIRED');
  }
  const errors = [];
  for (const [name, value] of Object.entries(expected)) {
    if(nonemptyExpectation(value)){
      const step=steps.find(step=>step.kind==='extract' && step.output_name===name);
      if(!validNonemptyExtractOutput(step,outputs[name])) errors.push(`输出 ${name} 没有符合提取契约的非空结构化结果`);
      continue;
    }
    if(emptyExpectation(value)){
      const step=steps.find(step=>step.kind==='extract' && step.output_name===name),output=outputs[name];
      if(!step || step.allow_empty!==true || !step.row_selector || !output || output.count!==0 || output.items?.length!==0 || output.coverage!=='empty' || output.truncated!==false ||
        output.empty_state?.confirmed!==true || output.empty_state.selector!==step.empty_state?.selector || output.empty_state.text!==step.empty_state?.text?.trim()) {
        errors.push(`输出 ${name} 没有当前可见页面的明确空态证据`);
      }
      continue;
    }
    const samples = Array.isArray(value) ? value : [value];
    if (!samples.length || samples.some(item => typeof item !== 'string' || !item.trim())) {
      errors.push(`输出 ${name} 的预期必须是非空文本或非空文本列表`);
      continue;
    }
    if (!Object.hasOwn(outputs, name)) {
      errors.push(`没有读回预期输出 ${name}`);
      continue;
    }
    const output = outputs[name];
    // URLs never satisfy content assertions, including structured extraction.
    const fields = steps.find(step => step.kind === 'extract' && step.output_name === name)?.fields || [];
    const contentFields = fields.filter(field => field.source !== 'href').map(field => field.name);
    const actual = Array.isArray(output) ? output.map(item => item.text || '').join('\n') :
      output?.items ? output.items.flatMap(item => contentFields.map(name => fields.find(field=>field.name===name)?.source==='content' ? item[name]?.text || '' : item[name] || '')).join('\n') : '';
    if (!actual.trim()) { errors.push(`输出 ${name} 的实际读取结果为空`); continue; }
    for (const sample of samples) if (!actual.includes(sample)) errors.push(`输出 ${name} 未包含预期内容 ${redactText(sample).slice(0, 120)}`);
  }
  return errors;
}

// Only module callers can shorten this deadline for isolated regression tests;
// the JSONL RPC exposes neither a budget override nor a cleanup configuration.
async function withDeadline(run,{budgetMs,startedMs=Date.now(),cleanupReserveMs=2000,onTimeout,errorCode}) {
  const reserve=Math.min(cleanupReserveMs,Math.max(1,budgetMs-1));
  const cutoff=startedMs+budgetMs-reserve;
  const control={expired:false,check(){
    if(this.expired || Date.now()>=cutoff) throw budgetError();
  }};
  let timer,cleanupTimer,cleanupPromise;
  const budgetError=()=>new WorkerError(errorCode==='BATCH_BUDGET' ? '评论批次已达到时间预算，已中断会话并保留已完成批次证据' : errorCode==='WAIT_TIMEOUT' ? '范围等待已达到时间预算，已中断会话并保留已取得证据' : '试跑已达到本轮总时间预算，已中断当前会话并保留已取得证据',errorCode);
  const expire=()=>{
    control.expired=true;
    if(!cleanupPromise){
      const remaining=Math.max(1,startedMs+budgetMs-Date.now());
      cleanupPromise=Promise.race([Promise.resolve().then(()=>onTimeout?.()),new Promise(resolve=>{cleanupTimer=setTimeout(resolve,remaining);})]).catch(()=>{});
    }
    return cleanupPromise;
  };
  const execution=Promise.resolve().then(()=>run(control));
  const expiration=new Promise((_,reject)=>{
    timer=setTimeout(()=>{
      expire().then(()=>reject(budgetError()));
    },Math.max(0,cutoff-Date.now()));
  });
  try{const value=await Promise.race([execution,expiration]);control.check();return value;}
  catch(error){
    if(control.expired || error.code===errorCode){await expire();throw budgetError();}
    throw error;
  }
  finally{clearTimeout(timer);clearTimeout(cleanupTimer);}
}

export const withVerifyDeadline=(run,options)=>withDeadline(run,{...options,errorCode:'VERIFY_BUDGET'});
export const withBatchDeadline=(run,options)=>withDeadline(run,{...options,errorCode:'BATCH_BUDGET'});
export const withWaitDeadline=(run,options)=>withDeadline(run,{...options,errorCode:'WAIT_TIMEOUT'});

export async function verify(params,{budgetMs:internalBudgetMs,cleanupReserveMs=2000,batchBudgetMs=15_000}={}) {
  if(!Number.isInteger(batchBudgetMs) || batchBudgetMs<1 || batchBudgetMs>15_000) throw new WorkerError('内部批次测试预算只能缩短既有上限','INVALID_INPUT');
  const startedMs=Date.now();
  const startedAt = new Date().toISOString();
  const session = sessionFor(params.task_id);
  resolveExecutionProfile(params.execution_profile);
  if(params.execution_profile!==session.executionProfile ||
    (isNativeUiProfile(session.executionProfile) ? !executionContractMatches(params.execution_contract,session.executionProfile) : params.execution_contract!==undefined))
    throw new WorkerError('候选执行模式与当前浏览器会话不一致，未导航或回放','EXECUTION_PROFILE_MISMATCH');
  const outputs = Object.create(null), evidence = [], errors = [],errorCodes=[],seekResults=[],stepTimings=[];
  let currentStepPosition=0;
  const expected = params.expected_outputs;
  // Validate assertions before any browser movement.
  assertExpected(expected, {});
  for (const value of Object.values(expected)) {
    if(emptyExpectation(value) || nonemptyExpectation(value)) continue;
    const samples = Array.isArray(value) ? value : [value];
    if (!samples.length || samples.some(item => typeof item !== 'string' || !item.trim())) {
      throw new WorkerError('每个输出预期必须是非空文本或非空文本列表', 'INVALID_EXPECTED_OUTPUT');
    }
  }
  if (!Array.isArray(params.steps) || !params.steps.length || params.steps.length > MAX_STEPS) {
    throw new WorkerError(`试跑要求 1–${MAX_STEPS} 个固定步骤`, 'INVALID_STEPS');
  }
  const entry = httpUrl(params.entry_url);
  requireOrigin(session, entry.href);
  const parameters = params.parameters && typeof params.parameters === 'object' ? params.parameters : {};
  const noteBinding=params.note_binding===undefined ? null : makeNoteBinding(params.note_binding,entry,params.steps,parameters);
  const verifyBudgetMs=90_000+(noteBinding?.seek_timeout_ms || 0);
  const effectiveBudget=Number.isInteger(internalBudgetMs) && internalBudgetMs>0 ? Math.min(verifyBudgetMs,internalBudgetMs) : verifyBudgetMs;
  let currentTrace=null,failureDiagnostics=null,budgetExpired=false,budgetContextClosed=false,batchContextClosed=false,batchCloseMs=null,entryFinished=null,closeStarted=null,closeMs=null;
  const retainFailure=(code,diagnostics=currentTrace?.diagnostics,phase=diagnostics?.phase)=>{
    const kind=params.steps[currentStepPosition-1]?.kind;
    if(!currentTrace || !diagnostics || !ACTION_KINDS.includes(kind) || typeof code!=='string' || !/^[A-Z][A-Z0-9_]{0,63}$/.test(code)) return;
    failureDiagnostics=structuredClone({step_position:currentStepPosition,kind,code,
      diagnostics:{...diagnostics,phase:phase || currentTrace.phase}});
  };
  const retainTiming=status=>{
    if(currentTrace && !stepTimings.some(item=>item.step_position===currentStepPosition)) stepTimings.push(currentTrace.snapshot(currentStepPosition,params.steps[currentStepPosition-1].kind,status));
  };
  const retainTrace=trace=>{
    for(const snapshot of [trace?.before,...(trace?.batch_evidence || []).map(item=>item.capture),trace?.after]) {
      if(snapshot && !evidence.some(item=>item.capture_id===snapshot.capture_id)) evidence.push(snapshot);
    }
  };
  try {
    await withVerifyDeadline(async control=>{
    try {
    await session.page.goto(entry.href, { waitUntil: 'domcontentloaded', timeout: 20_000 });
    control.check();
    await settle(session.page);
    control.check();
    evidence.push(await captureSession(session, '变参试跑入口'));
    entryFinished=Date.now();
    control.check();
    for (let index = 0; index < params.steps.length; index += 1) {
      currentStepPosition=index+1;
      if (shuttingDown) throw new WorkerError('学习工作进程正在退出', 'WORKER_CLOSING');
      control.check();
      const step = params.steps[index];
      if (!step || typeof step !== 'object' || !ACTION_KINDS.includes(step.kind)) throw new WorkerError(`第 ${index + 1} 步类型无效`, 'INVALID_STEPS');
      const actionParams = { ...step };
      if (step.kind === 'fill' && step.parameter) {
        if (!Object.hasOwn(parameters, step.parameter)) throw new WorkerError(`缺少运行参数 ${step.parameter}`, 'MISSING_PARAMETER');
        actionParams.value = String(parameters[step.parameter]);
      }
      if (step.target?.parameter) {
        if (!Object.hasOwn(parameters, step.target.parameter)) throw new WorkerError(`缺少动态目标参数 ${step.target.parameter}`, 'MISSING_PARAMETER');
        actionParams.target = { ...step.target, value: requireString(parameters[step.target.parameter], '动态目标参数', 2_000) };
      }
      if(step.until_target?.parameter){
        if(!Object.hasOwn(parameters,step.until_target.parameter)) throw new WorkerError(`缺少有界目标参数 ${step.until_target.parameter}`,'MISSING_PARAMETER');
        actionParams.until_target={...step.until_target,value:requireString(parameters[step.until_target.parameter],'有界目标参数',2_000)};
        delete actionParams.until_target.parameter;
      }
      if (['read', 'extract'].includes(step.kind)) requireString(step.output_name, 'output_name', 80);
      const result = await actionSession(session, actionParams, { captureBefore: false,noteBinding,batchBudgetMs,onTrace:trace=>{currentTrace=trace;} });
      control.check();
      if(step.until_target) seekResults.push({step_position:index+1,scrolls:result.result.scrolls,movements:result.result.movements,target_reached:result.result.target_reached,stop_reason:result.result.stop_reason});
      for(const batch of result.batch_evidence || []) if(!evidence.some(item=>item.capture_id===batch.capture.capture_id)) evidence.push(batch.capture);
      evidence.push(result.after);
      if (['read', 'extract'].includes(step.kind)) outputs[step.output_name] = result.result;
      retainTiming('passed');
      currentTrace=null;
    }
    errors.push(...assertExpected(expected, outputs, params.steps));
    requireBoundNotePage(session,noteBinding);
  } catch (error) {
    if(control.expired || error.code==='VERIFY_BUDGET') throw error;
    retainFailure(error.code,error.diagnostics || currentTrace?.diagnostics);
    if(error.code==='BATCH_BUDGET' && currentTrace?.batch_timeout){
      const step=params.steps[currentStepPosition-1],partial=currentTrace.batch_partial_result;
      if(currentTrace.batch_request_blocked!==true && step?.kind==='extract' && partial?.count>0 && validNonemptyExtractOutput(step,partial)) outputs[step.output_name]=structuredClone(partial);
      if(currentTrace.batch_request_blocked===true){errors.push('批次截止前已阻止未知请求，不提供该步部分输出');errorCodes.push('WRITE_REQUEST_BLOCKED');}
      batchContextClosed=currentTrace.batch_context_closed===true;batchCloseMs=currentTrace.batch_close_ms ?? null;
    }
    if(error.code==='WAIT_TIMEOUT' && currentTrace?.wait_timeout){
      batchContextClosed=currentTrace.wait_context_closed===true;batchCloseMs=currentTrace.wait_close_ms ?? null;
      if(currentTrace.wait_request_blocked===true){errors.push('范围等待截止前已阻止未知请求');errorCodes.push('WRITE_REQUEST_BLOCKED');}
    }
    if(error.seek_result) seekResults.push({step_position:currentStepPosition,...error.seek_result});
    errors.push(redactText(error.message));
    if(typeof error.code==='string' && /^[A-Z][A-Z0-9_]{0,63}$/.test(error.code)) errorCodes.push(error.code);
    for (const snapshot of [error.before, ...(error.batch_evidence || []).map(item=>item.capture),error.after]) {
      if (snapshot && !evidence.some(item => item.capture_id === snapshot.capture_id)) evidence.push(snapshot);
    }
    if (!session.closed && !session.page.isClosed()) {
      if(currentTrace) currentTrace.phase='failure_capture';
      await captureSession(session, '失败后页面状态').then(snapshot => evidence.push(snapshot)).catch(() => {});
    }
    if(control.expired) throw new WorkerError('总预算期间已中断取证','VERIFY_BUDGET');
    retainTiming('failed');
    }
    },{budgetMs:effectiveBudget,startedMs,cleanupReserveMs,onTimeout:()=>{
      budgetExpired=true;
      retainFailure('VERIFY_BUDGET',currentTrace?.diagnostics,currentTrace?.phase);
      if(entryFinished===null) entryFinished=Date.now();
      retainTiming('interrupted');
      retainTrace(currentTrace);
      if(currentTrace?.seek_result && !seekResults.some(item=>item.step_position===currentStepPosition)) {
        seekResults.push({step_position:currentStepPosition,...currentTrace.seek_result,target_reached:false,stop_reason:'time_budget'});
      }
      // Closing the context cancels pending DOM inspections, screenshots,
      // navigation and action waits. Merely racing them would leave late work
      // running after a timeout response and could append a false success.
      session.closed=true;session.ready=false;
      closeStarted=performance.now();
      session.context.once('close',()=>{budgetContextClosed=true;});
      const last=session.lastCapture;
      if(last && Date.parse(last.captured_at)>=startedMs && !evidence.some(item=>item.capture_id===last.capture_id)) evidence.push(last);
      session.lastCapture=null;
      endPlatformRequestPolicy(session.platformRequestPolicy);
      session.platformRequestPolicy=null;session.platformRequestPage=null;session.automating=false;
      return closeContext(session).finally(()=>{closeMs=Math.max(0,Math.round(performance.now()-closeStarted));});
    }});
  } catch(error) {
    if(error.code!=='VERIFY_BUDGET') throw error;
    retainTrace(currentTrace);
    if(!errorCodes.includes('VERIFY_BUDGET')) {errors.push(redactText(error.message));errorCodes.push('VERIFY_BUDGET');}
  }
  return {
    ...executionMetadata(session.executionProfile),
    passed: errors.length === 0,
    outputs, errors, evidence,error_codes:errorCodes,
    os: process.platform === 'win32' ? 'windows' : process.platform === 'darwin' ? 'macos' : process.platform,
    browser_version: session.context.browser()?.version() || 'unknown',
    identity_verification: 'operator_confirmed',
    started_at: startedAt, finished_at: new Date().toISOString(),
    model_calls: 0,
    ...(params.steps.some(step=>step?.until_target) ? {seek_results:snapshotSeekResults(seekResults)} : {}),
    ...(noteBinding?.seek_timeout_ms ? {verify_budget_ms:verifyBudgetMs} : {}),
    ...((budgetExpired && budgetContextClosed) || batchContextClosed ? {session_closed:true} : {}),
    ...(noteBinding ? {note_binding_result:bindingResult(noteBinding)} : {}),
    ...(failureDiagnostics ? {failure_diagnostics:structuredClone(failureDiagnostics)} : {}),
    step_timings:stepTimings.map(item=>({...item,phase_ms:{...item.phase_ms}})),
    verify_timing:{duration_ms:Math.max(0,Date.now()-startedMs),entry_ms:Math.max(0,(entryFinished ?? Date.now())-startedMs),
      close_ms:closeStarted===null ? batchCloseMs : closeMs ?? Math.max(0,Math.round(performance.now()-closeStarted))},
  };
}

const methods = { open, ready, capture, action, close, verify,
  status: async params => {
    const session = sessions.get(requireString(params.task_id, 'task_id', 128));
    if (session && !session.closed && !session.page.isClosed()) await refreshLoginDetection(session);
    return session && !session.closed ? sessionInfo(session) : { status: 'closed' };
  },
};

export async function dispatch(method, params = {}) {
  if (shuttingDown) throw new WorkerError('学习工作进程正在退出', 'WORKER_CLOSING');
  if (!Object.hasOwn(methods, method)) throw new WorkerError('不支持的工作进程方法', 'UNKNOWN_METHOD');
  return methods[method](params);
}

function shutdown() {
  if (shutdownPromise) return shutdownPromise;
  shuttingDown = true;
  for (const session of sessions.values()) {
    session.closed = true;
    session.ready = false;
    session.lastCapture = null;
  }
  shutdownPromise = (async () => {
    // Closing the context interrupts a pending goto/click/capture immediately;
    // it must not wait for the serial RPC loop to finish the current request.
    await Promise.allSettled([...contexts].map(context => context.close()));
    await Promise.allSettled([...closingAccounts.values()]);
    sessions.clear();
    accountOwners.clear();
  })();
  return shutdownPromise;
}

async function main() {
  await fs.mkdir(HOME, { recursive: true });
  const input = readline.createInterface({ input: process.stdin, crlfDelay: Infinity });
  const stop = () => {
    input.close();
    process.stdin.pause();
    void shutdown();
  };
  input.once('close', stop);
  process.stdin.once('error', stop);
  // A terminated parent may close its read pipe before closing our stdin.
  // Treat EPIPE as loss of the owner, never an unhandled stream exception.
  process.stdout.on('error', error => {
    if (error.code !== 'EPIPE') process.exitCode = 1;
    stop();
  });
  process.on('SIGINT', stop);
  process.on('SIGTERM', stop);
  const reply = value => {
    if (!shuttingDown && !process.stdout.destroyed) process.stdout.write(JSON.stringify(value) + '\n');
  };
  try {
    for await (const line of input) {
      if (shuttingDown) break;
      if (!line.trim()) continue;
      let request;
      try {
        if (line.length > 1_000_000) throw new WorkerError('请求超过大小限制', 'REQUEST_TOO_LARGE');
        request = JSON.parse(line);
        if (!request || typeof request !== 'object' || request.id === undefined) throw new WorkerError('请求缺少 id', 'INVALID_REQUEST');
        const result = await dispatch(request.method, request.params || {});
        reply({ id: request.id, result });
      } catch (error) {
        const code = error.code || 'BROWSER_ERROR';
        reply({ id: request?.id ?? null, error: { message: redactText(error.message).slice(0, 1_200), code,
          ...(error.before ? { before: error.before } : {}), ...(error.after ? { after: error.after } : {}),
          ...(error.batch_evidence ? {batch_evidence:error.batch_evidence} : {}),
          ...(error.session_closed===true ? {session_closed:true} : {}),
          ...(error.error_codes ? {error_codes:error.error_codes} : {}),
          ...(error.diagnostics ? { diagnostics: error.diagnostics } : {}) } });
      }
    }
  } finally {
    input.close();
    process.stdin.pause();
    await shutdown();
  }
}

if (process.argv[1] && import.meta.url === pathToFileURL(path.resolve(process.argv[1])).href) {
  main().catch(error => {
    process.stderr.write(`学习工作进程启动失败：${redactText(error.message)}\n`);
    process.exitCode = 1;
  });
}