// ==UserScript==
// @name         上海开放大学助手
// @namespace    https://l.shou.org.cn/
// @version      1.24.0
// @description  上海开放大学网上学习助手：自动识别课程任务、顺序导航、必看视频播放辅助，理清网课学习进度。仅供学习交流。
// @author       孤影
// @license      All Rights Reserved
// @copyright    2026 孤影 (QQ 2297311605)
// @tag          上海开放大学
// @tag          网上学习
// @tag          学习助手
// @tag          网课
// @tag          学习进度
// @match        https://l.shou.org.cn/*
// @match        http://l.shou.org.cn/*
// @match        https://*.shou.org.cn/*
// @run-at       document-start
// @noframes
// @grant        GM_getValue
// @grant        GM_setValue
// @grant        GM_notification
// ==/UserScript==

/*
 * 上海开放大学助手  作者：孤影  反馈 QQ：2297311605
 *
 * 【免责声明】
 * 1. 本脚本为免费工具，仅用于辅助整理和定位课程学习任务，方便学习者规划进度。
 * 2. 本脚本仅读取页面已显示的信息进行识别与导航，不向服务器写入完成状态、
 *    不伪造播放/学习记录、不篡改任何平台数据。
 * 3. 使用者应自行遵守所在学校及平台的相关规定，因使用本脚本产生的任何后果
 *    由使用者自行承担，作者不承担任何责任。
 * 4. 本脚本版权归作者「孤影」所有，仅供学习交流，禁止二次分发、商用或冒名发布。
 */

(function () {
  'use strict';

  const CONFIG = {
    scanDelay: 800,
    taskSwitchDelay: 3000,
    navigationTimeoutMs: 15000,
    learningLeaseMs: 120000,
    rescanInterval: 8000,
    taskSelectors: [
      '.sh-res',
      '.course_catalog .cell_info1 > a[href]',
      '[data-task-id]', '[data-activity-id]', '[class*="task"]',
      '[class*="activity"]', '[class*="catalog"] li', '[class*="chapter"] li',
      '.courseware_list li', '.course-list li', '.learn-list li',
      'a[href*="directory.aspx"][href*="cellId="]',
      'a[href*="directory.aspx"][href*="cellid="]',
      'a[href*="learn"]', 'a[href*="study"]', 'a[href*="activity"]'
    ],
    completedWords: ['已完成', '完成', 'completed', 'finished', '100%'],
    incompleteWords: ['未完成', '未学习', '待完成', '进行中', '学习中', '未开始', '0%'],
    completionPageWords: ['学习完成', '任务已完成', '本节已完成', '恭喜完成'],
    catalogUrlPattern: /\/study\/(?:learnCatalogNew|directory)\.aspx/i,
  };

  const KEYS = {
    position: 'shouHelper:lastPosition',
    autoReturn: 'shouHelper:autoReturn',
    smartMode: 'shouHelper:smartMode',
    minimized: 'shouHelper:minimized',
    sequence: 'shouHelper:sequencePosition',
    mandatoryVideoIds: 'shouHelper:mandatoryVideoIds',
    panelPosition: 'shouHelper:panelPosition',
  };

  const state = {
    tasks: [],
    scanTimer: null,
    lastCompletionDetected: false,
    videoBound: new WeakSet(),
    autoplayNoticeShown: false,
    pageAdvanceScheduled: false,
    navigationStarted: false,
    navGuardTimer: null,
    navTargetKey: null,
    visitedKeys: null,
    queueKeys: null,
    logs: [],
  };

  const LOG_LIMIT = 60;

  const RUN_SESSION_KEY = 'shouHelper:learningActiveUntil';
  const VISITED_SESSION_KEY = 'shouHelper:visitedTasks';
  const QUEUE_SESSION_KEY = 'shouHelper:taskQueue';

  function isCourseDirectoryPage() {
    return /\/study\/directory\.aspx/i.test(location.pathname);
  }

  function isCourseCatalogPage() {
    return /\/study\/learnCatalogNew\.aspx/i.test(location.pathname);
  }

  function isAutomationSupportPage() {
    return isCourseCatalogPage() || isCourseDirectoryPage() || /\/study\/assignment-preview\.aspx/i.test(location.pathname);
  }

  const storage = {
    get(key, fallback) {
      try {
        const value = typeof GM_getValue === 'function' ? GM_getValue(key) : localStorage.getItem(key);
        if (value === undefined || value === null) return fallback;
        if (value === 'true') return true;
        if (value === 'false') return false;
        return value;
      } catch (_) { return fallback; }
    },
    set(key, value) {
      try {
        if (typeof GM_setValue === 'function') return GM_setValue(key, value);
        localStorage.setItem(key, String(value));
      } catch (_) { return undefined; }
    },
  };

  function isLearningActive() {
    return Number(storage.get(RUN_SESSION_KEY, 0)) > Date.now();
  }

  function setLearningActive(active) {
    storage.set(RUN_SESSION_KEY, active ? Date.now() + CONFIG.learningLeaseMs : 0);
    const button = document.getElementById('shou-helper-start');
    if (button) button.textContent = active ? '停止学习' : '开始学习';
    const status = document.getElementById('shou-helper-status');
    if (status) {
      status.textContent = active ? '学习中' : '待开始';
      status.classList.toggle('active', active);
    }
  }

  function refreshLearningLease() {
    if (isLearningActive()) return storage.set(RUN_SESSION_KEY, Date.now() + CONFIG.learningLeaseMs);
    return undefined;
  }

  function taskVisitKey(task) {
    return cellIdFromUrl(task?.clickable?.href || '') || task?.identity || '';
  }

  function visitedTaskKeys() {
    if (state.visitedKeys) return new Set(state.visitedKeys);
    try {
      const saved = JSON.parse(storage.get(VISITED_SESSION_KEY, 'null'));
      const keys = Array.isArray(saved) ? saved : saved?.keys;
      state.visitedKeys = new Set(Array.isArray(keys) ? keys : []);
      return new Set(state.visitedKeys);
    } catch (_) {
      state.visitedKeys = new Set();
      return new Set();
    }
  }

  function resetVisitedTasks() {
    state.visitedKeys = new Set();
    return storage.set(VISITED_SESSION_KEY, '[]');
  }

  function taskQueueKeys() {
    if (state.queueKeys) return [...state.queueKeys];
    try {
      const saved = JSON.parse(storage.get(QUEUE_SESSION_KEY, 'null'));
      const keys = Array.isArray(saved) ? saved : saved?.keys;
      state.queueKeys = Array.isArray(keys) ? [...keys] : [];
      return [...state.queueKeys];
    } catch (_) {
      state.queueKeys = [];
      return [];
    }
  }

  function saveTaskQueue(tasks) {
    const keys = tasks.map(taskVisitKey).filter(Boolean);
    const existing = taskQueueKeys();
    if (existing.length > keys.length) return existing.length;
    state.queueKeys = [...keys];
    storage.set(QUEUE_SESSION_KEY, JSON.stringify(keys));
    return keys.length;
  }

  function clearTaskQueue() {
    state.queueKeys = [];
    return storage.set(QUEUE_SESSION_KEY, 'null');
  }

  function markVisitedKey(key) {
    if (!key) return;
    const keys = visitedTaskKeys();
    if (keys.has(key)) return;
    keys.add(key);
    state.visitedKeys = new Set(keys);
    return storage.set(VISITED_SESSION_KEY, JSON.stringify([...keys]));
  }

  function markTaskVisited(task) {
    return markVisitedKey(taskVisitKey(task));
  }

  function markTasksThrough(task) {
    const index = state.tasks.findIndex(item => item.identity === task?.identity);
    if (index < 0) return markTaskVisited(task);
    return Promise.allSettled(state.tasks.slice(0, index + 1).map(markTaskVisited));
  }

  function nextUnvisitedTask(tasks = state.tasks) {
    const visited = visitedTaskKeys();
    const queue = taskQueueKeys();
    if (queue.length) {
      const tasksByKey = new Map(tasks.map(task => [taskVisitKey(task), task]));
      for (const key of queue) {
        if (!visited.has(key) && tasksByKey.has(key)) return tasksByKey.get(key);
      }
      return null;
    }
    return tasks.find(task => {
      const key = taskVisitKey(task);
      return key && !visited.has(key);
    }) || null;
  }

  function debugFlow(event, extra = {}) {
    const current = currentSequenceTask();
    const next = nextUnvisitedTask();
    console.info('[助手流程]', {
      event,
      cellId: currentCellId(),
      current: current ? taskVisitKey(current) : null,
      next: next ? taskVisitKey(next) : null,
      queueLength: taskQueueKeys().length,
      visited: [...visitedTaskKeys()],
      active: isLearningActive(),
      scheduled: state.pageAdvanceScheduled,
      navigating: state.navigationStarted,
      ...extra,
    });
  }

  function normalizedText(element) {
    return (element?.innerText || element?.textContent || '')
      .replace(/\s+/g, ' ').trim().toLowerCase();
  }

  function isVisible(element) {
    if (!element?.isConnected) return false;
    const style = getComputedStyle(element);
    const rect = element.getBoundingClientRect();
    return style.display !== 'none' && style.visibility !== 'hidden' && rect.width > 0 && rect.height > 0;
  }

  function closestClickable(element) {
    return element.closest('a[href], button, [role="button"], [onclick]') ||
      element.querySelector('a[href], button, [role="button"], [onclick]') || element;
  }

  function classify(element) {
    if (element.matches('.course_catalog .cell_info1 > a[href]')) return 'available';
    if (element.matches('a[href*="directory.aspx"][href*="cellId="], a[href*="directory.aspx"][href*="cellid="]')) {
      return 'available';
    }
    if (element.matches('.sh-res')) {
      const statusImages = [...element.querySelectorAll('img[src], img[title]')];
      const statusTitles = statusImages.map(image => image.getAttribute('title') || '').join(' ');
      if (/已完成/.test(statusTitles)) return 'completed';
      if (/未看|未完成|未学习/.test(statusTitles)) return 'incomplete';
      if (element.querySelector('.sh-res-h > a[href], a[href*="cellId="]')) return 'available';
    }
    const text = normalizedText(element);
    const classText = `${element.className || ''} ${element.getAttribute('title') || ''} ${element.getAttribute('aria-label') || ''}`.toLowerCase();
    const combined = `${text} ${classText}`;
    const progressMatches = [...combined.matchAll(/(\d{1,3})\s*%/g)].map(match => Number(match[1]));
    if (progressMatches.some(value => value >= 100)) return 'completed';
    if (CONFIG.incompleteWords.some(word => combined.includes(word.toLowerCase()))) return 'incomplete';
    if (/\b(uncompleted|incomplete|pending|todo|doing)\b/.test(combined)) return 'incomplete';
    if (CONFIG.completedWords.some(word => combined.includes(word.toLowerCase()))) return 'completed';
    if (/\b(done|complete|completed|finished|success)\b/.test(combined)) return 'completed';
    if (progressMatches.some(value => value >= 0 && value < 100)) return 'incomplete';
    return 'unknown';
  }

  function uniqueTaskElements() {
    const found = [];
    const seen = new Set();
    document.querySelectorAll(CONFIG.taskSelectors.join(',')).forEach(element => {
      const isDirectoryLeaf = element.matches('.course_catalog .cell_info1 > a[href]');
      if ((!isDirectoryLeaf && !isVisible(element)) || element.closest('#shou-helper-panel')) return;
      if (element.closest('.course_catalog') && !isDirectoryLeaf) return;
      const directoryItem = element.closest('.cell_info1');
      const itemType = (directoryItem?.getAttribute('data-type') || '').toLowerCase();
      const itemText = normalizedText(element);
      if (itemType === 'exercise' || itemType === 'assignment' ||
          itemText.includes('在线练习') || itemText.includes('记分作业') ||
          /[（(]\s*练习\s*[）)]/.test(itemText)) return;
      const clickable = closestClickable(element);
      const text = itemText;
      if (text.length < 2 || text.length > 500) return;
      const status = classify(element);
      if (status === 'unknown') return;
      const identity = clickable.href || clickable.getAttribute('onclick') || `${text.slice(0, 100)}|${status}`;
      if (seen.has(identity)) return;
      seen.add(identity);
      found.push({ element, clickable, text, status, identity });
    });
    return found;
  }

  function scanTasks(showMessage = false) {
    refreshLearningLease();
    state.tasks = uniqueTaskElements();
    rememberMandatoryVideoTasks();
    if (isCourseDirectoryPage()) saveTaskQueue(state.tasks);
    releaseNavigationOnArrival();
    renderStats();
    if (showMessage) toast(state.tasks.length ? `已识别 ${state.tasks.length} 个任务` : '暂未识别到任务，请展开课程目录后重试');
    scheduleSmartTaskFlow();
  }

  function renderStats() {
    if (!isAutomationSupportPage()) return setText('shou-helper-count', '未在学习页');
    const queue = taskQueueKeys();
    const total = queue.length || state.tasks.length;
    if (!total) return setText('shou-helper-count', '0 项');
    const visited = visitedTaskKeys();
    const done = queue.length
      ? queue.filter(key => visited.has(key)).length
      : state.tasks.filter(task => visited.has(taskVisitKey(task))).length;
    setText('shou-helper-count', `已完成 ${done} / 共 ${total}`);
  }

  function releaseNavigationOnArrival() {
    if (!state.navigationStarted && !state.navGuardTimer) return;
    const arrived = state.navTargetKey && currentCellId() === state.navTargetKey;
    if (!arrived) return;
    clearNavigationGuard();
    state.navigationStarted = false;
    state.pageAdvanceScheduled = false;
    state.navTargetKey = null;
    debugFlow('navigate:arrived', { cellId: currentCellId() });
  }

  function setText(id, text) {
    const element = document.getElementById(id);
    if (element) element.textContent = text;
  }

  function saveTaskPosition(task) {
    return storage.set(KEYS.position, JSON.stringify({
      url: location.href,
      identity: task.identity,
      text: task.text.slice(0, 120),
      savedAt: Date.now(),
    }));
  }

  async function goToTask(task) {
    if (!task || state.navigationStarted) return;
    // 切换任务前，把上一条视频进度「定格」为历史行（清掉 key，下个视频新建一条）。
    const lastProgress = state.logs.find(entry => entry.key === 'video-progress');
    if (lastProgress) lastProgress.key = null;
    state.navigationStarted = true;
    const index = state.tasks.findIndex(item => item.identity === task.identity);
    debugFlow('navigate:start', { target: taskVisitKey(task), targetIndex: index });
    const writes = [
      refreshLearningLease(),
      markTaskVisited(task),
      saveTaskPosition(task),
      storage.set(QUEUE_SESSION_KEY, JSON.stringify(taskQueueKeys())),
      storage.set(KEYS.sequence, JSON.stringify({
      catalogUrl: sequenceScope(),
      identity: task.identity,
      index,
      savedAt: Date.now(),
      })),
    ];
    await Promise.allSettled(writes.map(write => Promise.resolve(write)));
    debugFlow('navigate:persisted', { target: taskVisitKey(task), targetIndex: index });
    task.element.scrollIntoView({ behavior: 'smooth', block: 'center' });
    const targetKey = taskVisitKey(task);
    state.navTargetKey = targetKey;
    clearNavigationGuard();
    state.navGuardTimer = setTimeout(() => {
      state.navGuardTimer = null;
      if (!state.navigationStarted) return;
      state.navigationStarted = false;
      state.pageAdvanceScheduled = false;
      debugFlow('navigate:timeout', { target: targetKey, targetIndex: index });
      if (isLearningActive()) advanceToNextTask('上一次切换未生效，正在重试下一项');
    }, CONFIG.navigationTimeoutMs);
    setTimeout(() => {
      const clickable = task.clickable;
      if (clickable.tagName === 'A') clickable.setAttribute('target', '_self');
      debugFlow('navigate:click', { target: targetKey, targetIndex: index });
      clickable.click();
    }, 450);
  }

  function clearNavigationGuard() {
    if (state.navGuardTimer) {
      clearTimeout(state.navGuardTimer);
      state.navGuardTimer = null;
    }
  }

  function goToNext() {
    const tasks = state.tasks;
    if (!tasks.length) return toast('当前目录没有识别到可学习任务');
    const next = nextUnvisitedTask(tasks);
    if (!next) return toast('当前目录任务已全部处理');
    toast(`即将进入：${next.text.slice(0, 32)}`);
    goToTask(next);
  }

  function isMandatoryVideoTask(task) {
    const text = task?.text || '';
    if (!text.includes('视频')) return false;
    if (text.includes('必看')) return true;
    const cellId = cellIdFromUrl(task?.clickable?.href || '');
    return cellId ? mandatoryVideoIds().has(cellId) : false;
  }

  function mandatoryVideoIds() {
    try {
      const values = JSON.parse(storage.get(KEYS.mandatoryVideoIds, '[]'));
      return new Set(Array.isArray(values) ? values : []);
    } catch (_) {
      return new Set();
    }
  }

  function rememberMandatoryVideoTasks() {
    const ids = mandatoryVideoIds();
    let changed = false;
    state.tasks.forEach(task => {
      if (!task.text.includes('视频') || !task.text.includes('必看')) return;
      const cellId = cellIdFromUrl(task.clickable?.href || '');
      if (cellId && !ids.has(cellId)) {
        ids.add(cellId);
        changed = true;
      }
    });
    if (changed) storage.set(KEYS.mandatoryVideoIds, JSON.stringify([...ids]));
  }

  function cellIdFromUrl(urlValue) {
    try {
      const url = new URL(urlValue, location.href);
      for (const [key, value] of url.searchParams.entries()) {
        if (key.toLowerCase() === 'cellid') return value;
      }
    } catch (_) {}
    return '';
  }

  function currentCellId() {
    return cellIdFromUrl(location.href);
  }

  function mandatoryVideoTasks() {
    return state.tasks.filter(isMandatoryVideoTask);
  }

  function currentTaskIndex(tasks) {
    const cellId = currentCellId();
    if (!cellId) return -1;
    return tasks.findIndex(task => cellIdFromUrl(task.clickable?.href || '') === cellId);
  }

  function currentSequenceTask() {
    const index = currentSequenceIndex();
    return index >= 0 ? state.tasks[index] : null;
  }

  function currentSequenceIndex() {
    const cellId = currentCellId();
    if (cellId) {
      const byCellId = state.tasks.findIndex(task => cellIdFromUrl(task.clickable?.href || '') === cellId);
      if (byCellId >= 0) return byCellId;
    }
    let saved = null;
    try { saved = JSON.parse(storage.get(KEYS.sequence, 'null')); } catch (_) {}
    if (saved?.catalogUrl !== sequenceScope()) return -1;
    const savedIndex = Number(saved?.index);
    if (Number.isInteger(savedIndex) && savedIndex >= 0 && savedIndex < state.tasks.length) return savedIndex;
    return saved ? state.tasks.findIndex(task => task.identity === saved.identity) : -1;
  }

  function advanceToNextTask(message) {
    if (!isLearningActive() || state.navigationStarted) return;
    const next = nextUnvisitedTask();
    if (!next) {
      storage.set(KEYS.sequence, 'null');
      setLearningActive(false);
      return notify('当前目录任务已全部进入完毕。');
    }
    debugFlow('advance', { target: taskVisitKey(next) });
    toast(message || `切换到下一项：${next.text.slice(0, 32)}`);
    goToTask(next);
  }

  function scheduleSmartTaskFlow() {
    if (!isLearningActive() || storage.get(KEYS.smartMode, false) !== true) return;
    if (state.pageAdvanceScheduled || state.navigationStarted) return;
    const current = currentSequenceTask();
    if (!current) {
      if (!state.tasks.length) return;
      const cellId = currentCellId();
      if (cellId) markVisitedKey(cellId);
      if (!nextUnvisitedTask()) return;
      state.pageAdvanceScheduled = true;
      debugFlow('schedule:forward', { cellId, delay: CONFIG.taskSwitchDelay });
      setTimeout(() => advanceToNextTask('定位不到当前任务，按队列进入下一项'), CONFIG.taskSwitchDelay);
      return;
    }
    markTaskVisited(current);
    if (isMandatoryVideoTask(current)) return;
    state.pageAdvanceScheduled = true;
    debugFlow('schedule', { current: taskVisitKey(current), delay: CONFIG.taskSwitchDelay });
    setTimeout(() => advanceToNextTask(`已进入，切换下一项：${current.text.slice(0, 28)}`), CONFIG.taskSwitchDelay);
  }

  function sameOriginDocuments() {
    const documents = [document];
    document.querySelectorAll('iframe').forEach(frame => {
      try {
        if (frame.contentDocument?.documentElement) documents.push(frame.contentDocument);
      } catch (_) {}
    });
    return documents;
  }

  function attachMandatoryVideoPlayback() {
    if (!isLearningActive()) return;
    const mandatoryTasks = mandatoryVideoTasks();
    if (currentTaskIndex(mandatoryTasks) < 0) return;
    sameOriginDocuments().forEach(doc => {
      doc.querySelectorAll('video.dplayer-video, .video_container video, video').forEach(video => {
        if (state.videoBound.has(video)) return;
        state.videoBound.add(video);
        const forceNormalSpeed = () => {
          if (video.playbackRate !== 1) video.playbackRate = 1;
          if (video.defaultPlaybackRate !== 1) video.defaultPlaybackRate = 1;
        };
        forceNormalSpeed();
        video.addEventListener('loadedmetadata', forceNormalSpeed);
        video.addEventListener('play', () => {
          forceNormalSpeed();
          logMessage('视频开始播放', 'evt');
        });
        video.addEventListener('ratechange', forceNormalSpeed);
        // 播放进度实时写进日志（同一条原地更新，最多每 2 秒刷一次，不刷屏）。
        video.addEventListener('timeupdate', () => {
          const now = Date.now();
          if (now - (video._shouLastLog || 0) < 2000) return;
          video._shouLastLog = now;
          const duration = video.duration;
          if (!Number.isFinite(duration) || duration <= 0) return;
          const percent = Math.min(100, Math.round(video.currentTime / duration * 100));
          logMessage(`视频播放 ${percent}%（${formatClock(video.currentTime)} / ${formatClock(duration)}）`, 'info', 'video-progress');
        });
        video.addEventListener('ended', () => {
          logMessage('视频播放 100%，已看完', 'done', 'video-progress');
          notify('视频已播放完成，正在切换下一项。');
          setTimeout(() => advanceToNextTask(), CONFIG.taskSwitchDelay);
        });
        const playResult = video.play();
        if (playResult?.catch) {
          playResult.catch(() => {
            if (state.autoplayNoticeShown) return;
            state.autoplayNoticeShown = true;
            toast('浏览器阻止了自动播放，请手动点击一次视频播放按钮');
          });
        }
      });
    });
  }

  function sequenceScope() {
    const url = new URL(location.href);
    let courseOpenId = '';
    for (const [key, value] of url.searchParams.entries()) {
      if (key.toLowerCase() === 'courseopenid') {
        courseOpenId = value;
        break;
      }
    }
    return courseOpenId ? `${url.origin}|${courseOpenId}` : `${url.origin}${url.pathname}`;
  }

  function expandCatalog() {
    const candidates = [...document.querySelectorAll('button, [role="button"], [onclick], .tree-node, .chapter, .folder')];
    let count = 0;
    candidates.forEach(element => {
      const text = normalizedText(element);
      const classText = String(element.className || '').toLowerCase();
      const collapsed = element.getAttribute('aria-expanded') === 'false' ||
        /collapsed|close|fold/.test(classText) || /展开|章节|单元|目录/.test(text);
      if (collapsed && isVisible(element) && !element.closest('#shou-helper-panel')) {
        const childList = element.nextElementSibling || element.parentElement?.querySelector('ul, .children');
        if (!childList || getComputedStyle(childList).display === 'none' || element.getAttribute('aria-expanded') === 'false') {
          element.click();
          count += 1;
        }
      }
    });
    document.querySelectorAll('.topic_condensation.am-icon-caret-right, .topic_condensation[class*="plus"]')
      .forEach(element => {
        if (isVisible(element)) {
          element.click();
          count += 1;
        }
      });
    document.querySelectorAll('.course_catalog .tr_topic').forEach(topic => {
      const children = topic.querySelector('.div_show_cell');
      if (!children || getComputedStyle(children).display !== 'none') return;
      const toggle = topic.querySelector('.show_topic') || topic.querySelector('.show_cell_list');
      if (!toggle || !isVisible(toggle)) return;
      toggle.click();
      count += 1;
    });
    setTimeout(() => scanTasks(), CONFIG.scanDelay);
    toast(count ? `已展开 ${count} 个折叠目录` : '目录已经全部展开');
  }

  function notify(message) {
    logMessage(message, 'done');
    if (typeof GM_notification === 'function') GM_notification({ title: '上海开放大学助手', text: message, timeout: 8000 });
    else if ('Notification' in window && Notification.permission === 'granted') new Notification('上海开放大学助手', { body: message });
    else alert(message);
  }

  function completionDetected() {
    const bodyText = normalizedText(document.body);
    return CONFIG.completionPageWords.some(word => bodyText.includes(word.toLowerCase()));
  }

  function checkCompletion() {
    const detected = completionDetected();
    if (!detected || state.lastCompletionDetected) return;
    state.lastCompletionDetected = true;
    notify('检测到当前任务已完成。');
    if (storage.get(KEYS.smartMode, false) === true) {
      return;
    } else if (storage.get(KEYS.autoReturn, false) === true) {
      setTimeout(returnToCatalog, 2500);
    }
  }

  function toggleLearning() {
    if (isLearningActive()) {
      setLearningActive(false);
      state.pageAdvanceScheduled = false;
      state.navigationStarted = false;
      clearNavigationGuard();
      return toast('自动学习已停止');
    }
    if (!isCourseCatalogPage() && !isCourseDirectoryPage()) return toast('请进入课程一级或二级目录后再开始学习');
    const startsFromCatalog = isCourseCatalogPage();
    storage.set(KEYS.sequence, 'null');
    resetVisitedTasks();
    if (startsFromCatalog) clearTaskQueue();
    storage.set(KEYS.smartMode, true);
    storage.set(KEYS.autoReturn, true);
    setLearningActive(true);
    state.pageAdvanceScheduled = false;
    scanTasks();
    const queueCount = taskQueueKeys().length;
    const current = currentSequenceTask();
    if (current) {
      markTasksThrough(current);
      attachMandatoryVideoPlayback();
      scheduleSmartTaskFlow();
    } else if (state.tasks.length) {
      goToNext();
    }
    const mandatoryCount = state.tasks.filter(task => task.text.includes('视频') && task.text.includes('必看')).length;
    debugFlow('manual:start', { startsFromCatalog, mandatoryCount, queueCount });
    toast(startsFromCatalog
      ? `已记录 ${mandatoryCount} 个必看视频，正在进入第一项`
      : `已建立 ${queueCount} 项二级目录学习队列`);
  }

  function returnToCatalog() {
    if (CONFIG.catalogUrlPattern.test(location.href)) return scanTasks(true);
    let saved;
    try { saved = JSON.parse(storage.get(KEYS.position, 'null')); } catch (_) {}
    if (saved?.url && CONFIG.catalogUrlPattern.test(saved.url)) location.href = saved.url;
    else if (history.length > 1) history.back();
    else toast('未保存课程目录地址，请手动返回目录');
  }

  function logMessage(message, level = 'info', key = null) {
    const now = new Date();
    const time = [now.getHours(), now.getMinutes(), now.getSeconds()]
      .map(value => String(value).padStart(2, '0')).join(':');
    // 带 key 的日志用于「原地更新」，例如视频播放进度，避免刷屏。
    if (key) {
      const existing = state.logs.find(entry => entry.key === key);
      if (existing) {
        existing.time = time;
        existing.message = message;
        existing.level = level;
        renderLog();
        return;
      }
    }
    state.logs.push({ time, message, level, key });
    if (state.logs.length > LOG_LIMIT) state.logs = state.logs.slice(-LOG_LIMIT);
    renderLog();
  }

  function formatClock(seconds) {
    if (!Number.isFinite(seconds) || seconds < 0) return '00:00';
    const total = Math.floor(seconds);
    const mm = String(Math.floor(total / 60)).padStart(2, '0');
    const ss = String(total % 60).padStart(2, '0');
    return `${mm}:${ss}`;
  }

  function renderLog() {
    const box = document.getElementById('shou-helper-log');
    if (!box) return;
    if (!state.logs.length) {
      box.innerHTML = '<div class="shou-helper-log-empty">暂无日志</div>';
      return;
    }
    box.innerHTML = state.logs.map(entry => {
      const level = ['evt', 'warn', 'done'].includes(entry.level) ? entry.level : '';
      return `<div class="shou-helper-log-line ${level}"><time>${entry.time}</time><span>${escapeHtml(entry.message)}</span></div>`;
    }).join('');
    box.scrollTop = box.scrollHeight;
  }

  function escapeHtml(text) {
    return String(text).replace(/[&<>"]/g, char => (
      { '&': '&amp;', '<': '&lt;', '>': '&gt;', '"': '&quot;' }[char]
    ));
  }

  function clearLog() {
    state.logs = [];
    renderLog();
  }

  function toast(message) {
    let element = document.getElementById('shou-helper-toast');
    if (!element) {
      element = document.createElement('div');
      element.id = 'shou-helper-toast';
      document.body.appendChild(element);
    }
    element.textContent = message;
    element.classList.add('visible');
    clearTimeout(element.hideTimer);
    element.hideTimer = setTimeout(() => element.classList.remove('visible'), 2600);
    logMessage(message, 'evt');
  }

  function placePanel(panel, left, top, save = false) {
    const maxLeft = Math.max(8, window.innerWidth - panel.offsetWidth - 8);
    const maxTop = Math.max(8, window.innerHeight - panel.offsetHeight - 8);
    const safeLeft = Math.min(Math.max(8, left), maxLeft);
    const safeTop = Math.min(Math.max(8, top), maxTop);
    panel.style.setProperty('left', `${safeLeft}px`, 'important');
    panel.style.setProperty('right', 'auto', 'important');
    panel.style.setProperty('top', `${safeTop}px`, 'important');
    if (save) storage.set(KEYS.panelPosition, JSON.stringify({ left: safeLeft, top: safeTop }));
  }

  function enablePanelDragging(panel) {
    const header = panel.querySelector('header');
    let drag = null;
    header.addEventListener('pointerdown', event => {
      if (event.button !== 0 || event.target.closest('button')) return;
      const rect = panel.getBoundingClientRect();
      drag = { pointerId: event.pointerId, offsetX: event.clientX - rect.left, offsetY: event.clientY - rect.top };
      header.setPointerCapture(event.pointerId);
      panel.classList.add('dragging');
      event.preventDefault();
    });
    header.addEventListener('pointermove', event => {
      if (!drag || event.pointerId !== drag.pointerId) return;
      placePanel(panel, event.clientX - drag.offsetX, event.clientY - drag.offsetY);
    });
    const finish = event => {
      if (!drag || event.pointerId !== drag.pointerId) return;
      const rect = panel.getBoundingClientRect();
      placePanel(panel, rect.left, rect.top, true);
      drag = null;
      panel.classList.remove('dragging');
    };
    header.addEventListener('pointerup', finish);
    header.addEventListener('pointercancel', finish);
  }

  function createPanel() {
    const panel = document.createElement('section');
    panel.id = 'shou-helper-panel';
    panel.innerHTML = `
      <header><span>上海开放大学助手</span><button id="shou-helper-minimize" title="最小化">−</button></header>
      <div class="shou-helper-body">
        <div class="shou-helper-summary"><span>进度 <b id="shou-helper-count">0 项</b></span><span id="shou-helper-status">待开始</span></div>
        <div class="shou-helper-actions">
          <button id="shou-helper-start">开始学习</button>
          <button id="shou-helper-expand">展开目录</button>
          <button id="shou-helper-return">返回目录</button>
        </div>
        <div class="shou-helper-log-head"><span>运行日志</span><button id="shou-helper-log-clear">清空</button></div>
        <div id="shou-helper-log"><div class="shou-helper-log-empty">暂无日志</div></div>
        <div class="shou-helper-footer">独乐乐不如众乐乐，有问题及时反馈 <b>QQ 2297311605</b>，<i>后续将支持直播出勤、答题等功能</i></div>
      </div>`;
    document.body.appendChild(panel);

    try {
      const savedPosition = JSON.parse(storage.get(KEYS.panelPosition, 'null'));
      if (Number.isFinite(savedPosition?.left) && Number.isFinite(savedPosition?.top)) {
        placePanel(panel, savedPosition.left, savedPosition.top);
      }
    } catch (_) {}
    enablePanelDragging(panel);

    panel.classList.toggle('minimized', storage.get(KEYS.minimized, false) === true);
    setLearningActive(isLearningActive());

    document.getElementById('shou-helper-start').addEventListener('click', toggleLearning);
    document.getElementById('shou-helper-expand').addEventListener('click', expandCatalog);
    document.getElementById('shou-helper-return').addEventListener('click', returnToCatalog);
    document.getElementById('shou-helper-log-clear').addEventListener('click', clearLog);
    document.getElementById('shou-helper-minimize').addEventListener('click', () => {
      panel.classList.toggle('minimized');
      storage.set(KEYS.minimized, panel.classList.contains('minimized'));
    });
    renderLog();
  }

  function addStyles() {
    const style = document.createElement('style');
    style.textContent = `
      @keyframes shou-panel-in{from{opacity:0;transform:translateY(-10px) scale(.97)}to{opacity:1;transform:translateY(0) scale(1)}}
      @keyframes shou-glow{0%,100%{box-shadow:0 0 0 0 rgba(16,185,129,.35)}50%{box-shadow:0 0 0 5px rgba(16,185,129,0)}}
      #shou-helper-panel{position:fixed!important;right:18px!important;top:82px!important;bottom:auto!important;width:min(288px,calc(100vw - 24px))!important;z-index:2147483647!important;color:#1e293b!important;border:1px solid #d1fae5!important;border-radius:16px!important;box-shadow:0 12px 34px rgba(6,95,70,.14),0 2px 6px rgba(6,95,70,.06)!important;background:#ffffff!important;font:14px/1.5 system-ui,"Microsoft YaHei",sans-serif!important;overflow:hidden!important;animation:shou-panel-in .3s cubic-bezier(.2,.9,.3,1.05)!important}
      #shou-helper-panel header{position:relative;display:flex;justify-content:space-between;align-items:center;padding:12px 16px;background:linear-gradient(120deg,#059669,#10b981 60%,#06b6d4);color:#fff;font-size:15px;font-weight:700;letter-spacing:.2px;cursor:move;user-select:none;touch-action:none}
      #shou-helper-panel.dragging{transition:none!important;box-shadow:0 18px 44px rgba(6,95,70,.22)!important;cursor:grabbing}
      #shou-helper-panel button{cursor:pointer;border:1px solid #ccfbf1;border-radius:9px;background:#f0fdfa;color:#0d9488;padding:9px 10px;font-size:13.5px;font-weight:600;transition:transform .15s,background .18s,border-color .18s,box-shadow .18s;-webkit-tap-highlight-color:transparent}
      #shou-helper-panel button:hover{background:#e6fffa;border-color:#5eead4;box-shadow:0 3px 10px rgba(16,185,129,.16);transform:translateY(-1px)}
      #shou-helper-panel button:active{transform:translateY(0) scale(.97)}
      #shou-helper-panel button:disabled{cursor:not-allowed;opacity:.45;transform:none;box-shadow:none}
      #shou-helper-minimize{border:0!important;background:transparent!important;color:#fff!important;font-size:18px;line-height:1;padding:0 5px!important;opacity:.9;box-shadow:none!important}
      #shou-helper-minimize:hover{opacity:1;transform:none!important;background:rgba(255,255,255,.2)!important;border-radius:7px!important}
      .shou-helper-body{padding:14px 16px 16px}.minimized .shou-helper-body{display:none}
      .shou-helper-summary{display:flex;justify-content:space-between;align-items:center;margin-bottom:13px;color:#64748b;font-size:13px}
      #shou-helper-count{color:#065f46;font-weight:700}
      #shou-helper-status{padding:3px 10px;border-radius:999px;background:#ecfdf5;color:#059669;font-size:12px;font-weight:600;border:1px solid #a7f3d0}
      #shou-helper-status.active{background:#059669;color:#fff;border-color:#059669;animation:shou-glow 2.2s ease-in-out infinite}
      .shou-helper-actions{display:grid;grid-template-columns:1fr 1fr;gap:9px}
      #shou-helper-start{grid-column:1/-1;background:linear-gradient(120deg,#059669,#10b981)!important;border:0!important;color:#fff!important;font-weight:700;font-size:14.5px;letter-spacing:.3px;padding:11px!important;box-shadow:0 6px 16px rgba(16,185,129,.35)!important;background-size:160% 100%!important;transition:background-position .45s,transform .15s,box-shadow .2s!important}
      #shou-helper-start:hover{background-position:100% 0!important;transform:translateY(-1px);box-shadow:0 9px 22px rgba(16,185,129,.45)!important}
      .shou-helper-log-head{display:flex;justify-content:space-between;align-items:center;margin-top:14px;margin-bottom:6px;color:#64748b;font-size:12px;font-weight:600}
      #shou-helper-log-clear{border:0!important;background:transparent!important;color:#0d9488!important;font-size:11.5px;padding:0!important;font-weight:600;box-shadow:none!important}
      #shou-helper-log-clear:hover{background:transparent!important;text-decoration:underline;transform:none!important;box-shadow:none!important}
      #shou-helper-log{height:112px;overflow-y:auto;background:#f0fdf9;border:1px solid #d1fae5;border-radius:9px;padding:7px 9px;font:11.5px/1.55 "SFMono-Regular",Consolas,"Microsoft YaHei",monospace;color:#334155;scrollbar-width:thin}
      #shou-helper-log::-webkit-scrollbar{width:6px}#shou-helper-log::-webkit-scrollbar-thumb{background:#a7f3d0;border-radius:6px}
      .shou-helper-log-line{display:flex;gap:6px;padding:1px 0;word-break:break-all}
      .shou-helper-log-line time{color:#94a3b8;flex-shrink:0}
      .shou-helper-log-line.evt{color:#0d9488}.shou-helper-log-line.warn{color:#d97706}.shou-helper-log-line.done{color:#059669;font-weight:600}
      .shou-helper-log-empty{color:#94a3b8;text-align:center;padding-top:38px}
      .shou-helper-footer{margin-top:13px;padding-top:11px;border-top:1px dashed #d1fae5;color:#94a3b8;font-size:11.5px;line-height:1.7;text-align:center}.shou-helper-footer b{color:#059669;font-weight:700}.shou-helper-footer i{font-style:normal;color:#b6c0cc}
      #shou-helper-toast{position:fixed;left:50%;bottom:38px;z-index:2147483647;transform:translate(-50%,20px);background:#065f46;color:#fff;padding:11px 20px;border-radius:10px;font-weight:600;font-size:13.5px;box-shadow:0 10px 26px rgba(6,95,70,.3);opacity:0;pointer-events:none;transition:.26s cubic-bezier(.2,.9,.3,1.05)}#shou-helper-toast.visible{opacity:1;transform:translate(-50%,0)}
    `;
    (document.head || document.documentElement).appendChild(style);
  }

  function init() {
    if (!document.body || document.getElementById('shou-helper-panel')) return;
    try {
      if (!isAutomationSupportPage()) setLearningActive(false);
      addStyles();
      createPanel();
      scanTasks();
      attachMandatoryVideoPlayback();
      debugFlow('page:init');
      console.info('%c上海开放大学助手%c v1.24.0 · 作者 孤影 · 反馈 QQ 2297311605',
        'color:#059669;font-weight:700', 'color:#64748b', location.href);
      logMessage(`助手已启动 v1.24.0，识别到 ${state.tasks.length} 个任务`, 'done');
      state.scanTimer = setInterval(() => {
        scanTasks();
        checkCompletion();
        attachMandatoryVideoPlayback();
      }, CONFIG.rescanInterval);
      const observer = new MutationObserver(() => {
        clearTimeout(observer.debounceTimer);
        observer.debounceTimer = setTimeout(() => {
          scanTasks();
          attachMandatoryVideoPlayback();
        }, CONFIG.scanDelay);
      });
      observer.observe(document.body, { childList: true, subtree: true });
    } catch (error) {
      console.error('[上海开放大学助手] 启动失败', error);
      const badge = document.createElement('button');
      badge.type = 'button';
      badge.textContent = '学习助手启动失败，点击查看错误';
      badge.style.cssText = 'position:fixed;right:18px;top:82px;z-index:2147483647;padding:12px;background:#c62828;color:#fff;border:0;border-radius:8px;cursor:pointer';
      badge.addEventListener('click', () => alert(`上海开放大学助手启动失败：${error.message || error}`));
      document.body.appendChild(badge);
    }
  }

  function boot() {
    if (document.body) init();
    else document.addEventListener('DOMContentLoaded', init, { once: true });
  }

  boot();
})();