// ==UserScript==
// @name         教育干部网络学院 / 大学生网络党校 · 看课助手（纯净版）
// @namespace    leemo-enaea-clean-helper
// @version      1.2.0
// @description  全自动挂课：静音播放、防暂停、卡死自救、自动答题、自动下一节。
// @author       leemo
// @copyright    2026, leemo <781783460@qq.com>
// @supportURL   mailto:781783460@qq.com
// @match        *://*.enaea.edu.cn/*
// @match        *://*.uucps.edu.cn/*
// @grant        GM_addStyle
// @grant        GM_getValue
// @grant        GM_setValue
// @run-at       document-start
// ==/UserScript==

(function () {
  'use strict';

  /* ===================== 配置持久化 ===================== */
  var CFG_KEY = 'eas_cfg_v1';
  var DEFAULTS = {
    rate: 1,            // 播放倍速
    autoNext: true,     // 播完自动下一节
    blockVerify: true,  // 拦截学时验证请求，防止弹验证码打断
    autoDialog: true,   // 自动关闭"温馨提示"类弹窗
    autoAnswer: true,   // 自动答题（拿到答案选对，拿不到就轮换穷举，答错继续）
    autoReload: true,   // 长时间无进展 / 找不到下一节时自动刷新自救
    autoEnter: true,    // 课程列表页自动点"继续学习/开始学习"进入未完成课程
    mute: true          // 静音
  };
  var cfg = (function () {
    var saved = {};
    try { saved = GM_getValue(CFG_KEY, {}) || {}; } catch (e) {}
    var out = {};
    for (var k in DEFAULTS) {
      out[k] = Object.prototype.hasOwnProperty.call(saved, k) ? saved[k] : DEFAULTS[k];
    }
    return out;
  })();
  function saveCfg() { try { GM_setValue(CFG_KEY, cfg); } catch (e) {} }
  function log() {
    var a = Array.prototype.slice.call(arguments);
    console.log('%c[看课助手]', 'color:#2b6cb0', a.join(' '));
  }

  /* ===================== 拦截 XHR / fetch =====================
     目的：掐掉 learnVerify 一类的学时校验/验证码请求，避免播放中途被弹窗打断。
     做法：不真正发包，直接伪造一个成功响应返回给页面。                        */
  function isVerifyUrl(url) {
    return /learnVerify|learnValid|checkCode|studyValid/i.test(String(url || ''));
  }
  function isQuestionUrl(url) {
    return /getQuestions|validQuestions|questionList|\/questions/i.test(String(url || ''));
  }
  // 从拦截到的题目数据里取正确答案；取不到就返回 null，之后随机选
  function getCorrectAnswer() {
    var q = window.__EAS_Q;
    if (!q) return null;
    var c = q.correctAnswer || q.answer || q.rightAnswer || q.correct || q.answers;
    if (c == null) return null;
    if (Object.prototype.toString.call(c) === '[object Array]') return c.join('');
    if (typeof c === 'object') return JSON.stringify(c);
    return String(c);
  }
  function fakeXhr(xhr, text) {
    setTimeout(function () {
      try {
        Object.defineProperty(xhr, 'readyState', { value: 4, configurable: true });
        Object.defineProperty(xhr, 'status', { value: 200, configurable: true });
        Object.defineProperty(xhr, 'statusText', { value: 'OK', configurable: true });
        Object.defineProperty(xhr, 'responseText', { value: text, configurable: true });
        Object.defineProperty(xhr, 'response', { value: text, configurable: true });
        xhr.dispatchEvent(new Event('readystatechange'));
        xhr.dispatchEvent(new Event('load'));
        xhr.dispatchEvent(new Event('loadend'));
      } catch (e) { log('伪造响应失败', e.message); }
    }, 0);
  }
  function installXHRHook() {
    var P = window.XMLHttpRequest && window.XMLHttpRequest.prototype;
    if (!P) return;
    var origOpen = P.open, origSend = P.send;
    P.open = function (method, url) {
      try { this.__easUrl = String(url || ''); } catch (e) {}
      return origOpen.apply(this, arguments);
    };
    P.send = function () {
      var self = this;
      try {
        if (cfg.blockVerify && isVerifyUrl(this.__easUrl)) {
          log('已拦截验证请求:', this.__easUrl);
          fakeXhr(this, '{"code":0,"msg":null,"data":{"status":1}}');
          return;
        }
        if (isQuestionUrl(this.__easUrl)) {
          this.addEventListener('load', function () {
            try {
              var j = JSON.parse(self.responseText);
              if (j && j.data) { window.__EAS_Q = j.data; log('已捕获题目数据'); }
            } catch (e) {}
          });
        }
      } catch (e) {}
      return origSend.apply(this, arguments);
    };
  }
  function installFetchHook() {
    if (!window.fetch) return;
    var orig = window.fetch;
    window.fetch = function (input) {
      try {
        var url = typeof input === 'string' ? input : (input && input.url) || '';
        if (cfg.blockVerify && isVerifyUrl(url)) {
          log('已拦截 fetch 验证请求:', url);
          return Promise.resolve(new Response('{"code":0,"msg":null,"data":{"status":1}}', {
            status: 200, headers: { 'Content-Type': 'application/json' }
          }));
        }
      } catch (e) {}
      var p = orig.apply(this, arguments);
      if (isQuestionUrl(url) && p && typeof p.then === 'function') {
        p.then(function (res) {
          try {
            if (res && typeof res.clone === 'function') {
              res.clone().json().then(function (j) {
                if (j && j.data) { window.__EAS_Q = j.data; log('已捕获题目数据(fetch)'); }
              }).catch(function () {});
            }
          } catch (e) {}
          return res;
        }).catch(function () {});
      }
      return p;
    };
  }
  installXHRHook();

  /* ===================== 视频查找（含同域 iframe） ===================== */
  function findVideo() {
    var v = document.querySelector('video');
    if (v) return v;
    var frames = document.querySelectorAll('iframe');
    for (var i = 0; i < frames.length; i++) {
      try {
        var d = frames[i].contentDocument;
        if (d) { var iv = d.querySelector('video'); if (iv) return iv; }
      } catch (e) { /* 跨域 iframe，跳过 */ }
    }
    return null;
  }

  /* ===================== 目录解析与跳转 ===================== */
  var CATALOG_SELECTORS = [
    'ul.lis-content li.lis-inside-content',
    '.catalog-list li',
    '.chapter-list li',
    '.course-catalog li',
    'ul.catalog li',
    '[class*=catalog] li',
    '[class*=Catalog] li',
    '[class*=directory] li',
    '[class*=syllabus] li'
  ];
  function getCatalogItems() {
    for (var s = 0; s < CATALOG_SELECTORS.length; s++) {
      var list = document.querySelectorAll(CATALOG_SELECTORS[s]);
      if (list && list.length > 1) return Array.prototype.slice.call(list);
    }
    return [];
  }
  function extractUrl(li) {
    var a = li.querySelector('a[href]');
    if (a && a.href && !/^javascript:/i.test(a.href)) return a.href;
    var node = li.querySelector('h2[onclick], .title[onclick], [onclick]');
    var on = node ? node.getAttribute('onclick') : '';
    if (!on) return '';
    var m = on.match(/location\.href\s*=\s*['"]([^'"]+)['"]/);
    if (m) return m[1];
    m = on.match(/open\s*\(\s*['"](\/[^'"]+)['"]/);
    if (m) return m[1];
    m = on.match(/['"](\/[^'"\s]{4,})['"]/);
    if (m) return m[1];
    return '';
  }
  function isFinished(li) {
    var txt = (li.innerText || '').replace(/\s+/g, ' ');
    if (/100\s*%/.test(txt)) return true;
    if (/已完成|已学习|已看完/.test(txt)) return true;
    if (li.querySelector('.xxzt_icon3, .icon-finish, .finished, .is-finish')) return true;
    var btn = li.querySelector('button, .btn, .status');
    var bt = btn ? (btn.innerText || '').trim() : '';
    if (/已完成|已学习|已看完/.test(bt)) return true;
    return false;
  }
  function currentIndex(items) {
    for (var i = 0; i < items.length; i++) {
      if (items[i].querySelector('#top_play, .playing, .current, .active, .on')) return i;
    }
    for (var j = 0; j < items.length; j++) {
      var u = extractUrl(items[j]);
      if (u && u.indexOf(location.pathname) !== -1 && location.pathname.length > 3) return j;
    }
    return -1;
  }
  function fallbackNextButton() {
    var cands = document.querySelectorAll('a, button, .btn, span, div');
    for (var i = 0; i < cands.length; i++) {
      var el = cands[i];
      var t = (el.innerText || '').trim();
      if (!t || t.length > 10) continue;
      if (/^下一(节|章|课|个)|下一节|下一章/.test(t)) return { el: el };
    }
    return null;
  }
  function nextLesson() {
    var items = getCatalogItems();
    if (items.length) {
      var cur = currentIndex(items);
      var start = cur >= 0 ? cur + 1 : 0;
      for (var i = start; i < items.length; i++) {
        if (isFinished(items[i])) continue;
        var url = extractUrl(items[i]);
        var title = (items[i].innerText || '').replace(/\s+/g, ' ').slice(0, 40);
        if (url) {
          log('跳转下一节:', title, url);
          location.href = url;
          return true;
        }
        var clickable = items[i].querySelector('h2[onclick], .title[onclick], [onclick], a');
        if (clickable) {
          log('点击下一节:', title);
          clickable.click();
          return true;
        }
      }
      // 末尾没找到，从头再找一遍未完成的
      for (var j = 0; j < items.length; j++) {
        if (isFinished(items[j])) continue;
        var u2 = extractUrl(items[j]);
        if (u2 && u2 !== location.href) { log('从头跳转未完成项:', u2); location.href = u2; return true; }
      }
    }
    var fb = fallbackNextButton();
    if (fb && fb.el) { fb.el.click(); return true; }
    return false;
  }

  /* ===================== 弹窗处理 ===================== */
  function closeDialogs() {
    var dialogs = document.querySelectorAll('div.el-dialog, .el-message-box, .layui-layer, .el-overlay-dialog');
    for (var i = 0; i < dialogs.length; i++) {
      var d = dialogs[i];
      if (!d.getBoundingClientRect().height) continue;   // 不可见的不处理
      var label = (d.getAttribute('aria-label') || '') + ' ' + (d.innerText || '');
      if (/练习|考试|答题|测验|验证/.test(label)) continue;   // 答题弹窗不碰
      if (!/提示|温馨提示|注意|提醒/.test(label)) continue;
      var btn = d.querySelector('.el-dialog__headerbtn, .el-message-box__btns button, .el-button--primary, .layui-layer-btn0, .el-dialog__footer button');
      if (btn) { btn.click(); log('已关闭提示弹窗'); }
    }
  }

  /* ===================== 自动答题 =====================
     策略：接口能拿到正确答案就选对；拿不到就选第一个提交（答错也放行）。
     支持 Element UI(el-dialog) / layui / ant-design 三种常见弹窗，radio/checkbox/自定义选项三种题型。 */
  var QUIZ_SELECTORS = [
    'div.el-dialog[aria-label="随机练习"]',
    'div.el-dialog[aria-label*="练习"]',
    'div.el-dialog[aria-label*="答题"]',
    'div.el-dialog[aria-label*="测验"]',
    'div.el-dialog[aria-label*="考核"]',
    '.el-dialog', '.el-drawer', '.ant-modal', '.ant-drawer',
    '.layui-layer', '.modal', '[class*=question]', '[class*=Question]'
  ];
  function findQuizDialog(ignoreFlag) {
    for (var i = 0; i < QUIZ_SELECTORS.length; i++) {
      var list = document.querySelectorAll(QUIZ_SELECTORS[i]);
      for (var j = 0; j < list.length; j++) {
        var d = list[j];
        if (!d.getBoundingClientRect().height) continue;          // 不可见
        if (!ignoreFlag && d.__easAnswered) continue;              // 本轮已处理
        var txt = d.innerText || '';
        if (/温馨提示|^提示$/.test(txt.slice(0, 20))) continue;    // 排除纯提示框
        var hasOpt = d.querySelector('input[type=radio], input[type=checkbox], .el-radio, .el-checkbox, .option, .answer-item, .question-option');
        if (!hasOpt) continue;                                     // 没有可选项，不是答题框
        var hasSubmit = d.querySelector('.submit, .el-button--primary, button');
        if (!hasSubmit) continue;
        return d;
      }
    }
    return null;
  }
  function optionText(el) {
    var v = '';
    if (el.value) v += el.value + ' ';
    var p = el.closest ? el.closest('label, .el-radio, .el-checkbox, li, .option') : null;
    if (p && p.innerText) v += p.innerText;
    return (v || '').replace(/\s+/g, ' ').trim();
  }
  // 题目指纹：题干+选项文本，用于记录"这道题已经试过几种选法"
  // 用 sessionStorage 持久化，跳转到下一节后仍能接着轮换，不会每次从头选第一个
  var answerSeq = (function () {
    try { return JSON.parse(sessionStorage.getItem('eas_seq') || '{}') || {}; } catch (e) { return {}; }
  })();
  var globalTries = (function () {
    try { return parseInt(sessionStorage.getItem('eas_gt') || '0', 10) || 0; } catch (e) { return 0; }
  })();
  function persistSeq() {
    try {
      var keys = Object.keys(answerSeq);
      if (keys.length > 60) { for (var i = 0; i < keys.length - 60; i++) delete answerSeq[keys[i]]; }
      sessionStorage.setItem('eas_seq', JSON.stringify(answerSeq));
      sessionStorage.setItem('eas_gt', String(globalTries));
    } catch (e) {}
  }
  function quizText(d) {
    return (d.innerText || '').replace(/\s+/g, ' ').slice(0, 150);
  }
  // 超时强行跳过：优先点关闭，其次隐藏遮罩，最后找"跳过/继续"按钮
  function forceCloseQuiz(d) {
    var closeBtn = d.querySelector('.el-dialog__headerbtn, .el-dialog__close, .layui-layer-close, .ant-modal-close, .close, .dialog-close, .el-drawer__close-btn');
    if (closeBtn) { try { closeBtn.click(); } catch (e) {} }
    var btns = d.querySelectorAll('button, a, span');
    for (var j = 0; j < btns.length; j++) {
      var t = (btns[j].innerText || '').trim();
      if (/^(跳过|略过|关闭|继续学习|继续播放|下次再说)$/.test(t)) { try { btns[j].click(); } catch (e) {} break; }
    }
    try { d.style.display = 'none'; } catch (e) {}
    var masks = document.querySelectorAll('.el-overlay, .layui-layer-shade, .ant-modal-mask, .v-modal, .el-loading-mask');
    for (var i = 0; i < masks.length; i++) {
      try { if (masks[i].style.display !== 'none') masks[i].style.display = 'none'; } catch (e) {}
    }
    d.__easAnswered = true;
    d.__easKilled = true;
    toast('答题超时，已强制跳过');
    log('强制关闭答题弹窗');
  }
  function tryAnswer() {
    if (!cfg.autoAnswer) return false;
    var d = findQuizDialog();
    if (!d) return false;

    var correct = getCorrectAnswer();
    var nodes = d.querySelectorAll('input[type=radio], input[type=checkbox]');
    var items = [];
    if (nodes.length) {
      for (var i = 0; i < nodes.length; i++) {
        if (nodes[i].disabled) continue;
        items.push({ el: nodes[i], text: optionText(nodes[i]), multi: nodes[i].type === 'checkbox' });
      }
    }
    if (!items.length) {
      var alt = d.querySelectorAll('.el-radio, .el-checkbox, .option, .answer-item, .question-option, li');
      for (var k = 0; k < alt.length; k++) {
        var t = (alt[k].innerText || '').replace(/\s+/g, ' ').trim();
        if (!t || t.length > 200) continue;
        items.push({ el: alt[k], text: t, multi: false });
      }
    }
    if (!items.length) return false;

    // 同一弹窗存在超过 2 分钟仍未消失 -> 强制跳过，绝不停在这里等人工
    if (!d.__easFirst) d.__easFirst = Date.now();
    if (Date.now() - d.__easFirst > 120000) { forceCloseQuiz(d); return false; }

    d.__easAnswered = true;
    setTimeout(function () { d.__easAnswered = false; }, 1800);   // 1.8 秒后进入下一轮尝试

    var key = quizText(d), n = items.length;
    var tries = (answerSeq[key] = (answerSeq[key] || 0) + 1);
    var picked = [];
    if (correct) {
      log('参考答案:', correct);
      for (var m = 0; m < items.length; m++) {
        if (items[m].text.indexOf(correct) !== -1) picked.push(items[m]);
      }
      // 参考答案是 "AB" 这种多选串时，逐字符匹配
      if (!picked.length && correct.length > 1) {
        for (var c = 0; c < correct.length; c++) {
          var ch = correct[c];
          for (var n = 0; n < items.length; n++) {
            if (items[n].text.indexOf(ch) === 0 || items[n].text.indexOf(ch + '.') === 0) {
              picked.push(items[n]); break;
            }
          }
        }
      }
    }
    if (!picked.length) {
      // 没有参考答案：按尝试次数轮换选项，单选题在 n 次内必然命中，全程无需人工
      if (!items[0].multi) {
        var base = tries - 1;
        if (tries === 1) base = globalTries++;      // 题目每次随机变时也能持续轮换
        var idx = ((base % n) + n) % n;
        picked.push(items[idx]);
        log('盲选第 ' + tries + ' 次：选第 ' + (idx + 1) + '/' + n + ' 项');
      } else if (tries <= n) {
        picked.push(items[(tries - 1) % n]);
        log('多选盲选第 ' + tries + ' 次：只选第 ' + tries + ' 项');
      } else if (tries === n + 1) {
        picked = items.slice();
        log('多选盲选：全选');
      } else {
        var cnt = 1 + Math.floor(Math.random() * n);
        var pool = items.slice();
        for (var q = 0; q < cnt && pool.length; q++) {
          picked.push(pool.splice(Math.floor(Math.random() * pool.length), 1)[0]);
        }
        log('多选盲选：随机 ' + picked.length + ' 项');
      }
    }
    persistSeq();

    // 去重：同一 checkbox 点两次会取消勾选
    var seen = [];
    picked = picked.filter(function (it) {
      if (seen.indexOf(it.el) !== -1) return false;
      seen.push(it.el); return true;
    });

    for (var p = 0; p < picked.length; p++) {
      try { picked[p].el.click(); } catch (e) {}
    }

    var submit = d.querySelector('.submit') ||
      d.querySelector('.el-dialog__footer .el-button--primary') ||
      d.querySelector('.el-button--primary') ||
      d.querySelector('.el-dialog__footer button') ||
      d.querySelector('.dialog-footer button') ||
      d.querySelector('.layui-layer-btn0') ||
      d.querySelector('.ant-modal-footer button');
    if (submit) {
      setTimeout(function () {
        try { submit.click(); log('已提交答案'); } catch (e) {}
        setTimeout(closeResult, 900);
      }, 300);
      toast(correct ? '已自动答题（参考答案 ' + correct + '）' : '已自动答题（盲选第 ' + tries + ' 轮）');
      return true;
    }
    return false;
  }
  function closeResult() {
    var boxes = document.querySelectorAll('.el-message-box, .el-dialog, .ant-modal, .layui-layer');
    for (var i = 0; i < boxes.length; i++) {
      var b = boxes[i];
      if (!b.getBoundingClientRect().height) continue;
      var txt = (b.innerText || '').replace(/\s+/g, ' ');
      var isResult = b.classList.contains('el-message-box') ||
        /回答正确|回答错误|答对|答错|恭喜|很遗憾|正确答案|本题/.test(txt);
      if (!isResult) continue;
      var btn = b.querySelector('.el-message-box__btns button') ||
        b.querySelector('.el-button--primary') ||
        b.querySelector('.el-dialog__footer button') ||
        b.querySelector('.layui-layer-btn0') ||
        b.querySelector('.ant-modal-footer button');
      if (btn) { try { btn.click(); log('已关闭答题结果框'); } catch (e) {} return true; }
    }
    return false;
  }

  /* ===================== 播放守护 ===================== */
  var video = null, lastT = -1, stall = 0, handled = false;

  function bindVideo(v) {
    video = v;
    v.__easSrc = v.currentSrc || v.src || '';
    lastT = -1; stall = 0; handled = false;
    v.addEventListener('ended', function () { onEnded(); }, { once: true });
    v.addEventListener('pause', function () {
      setTimeout(function () { if (video && !video.ended && video.paused) video.play().catch(function () {}); }, 500);
    });
    log('已接管视频');
  }

  function onEnded() {
    if (handled) return;
    handled = true;
    setState('本节已完成', '#276749');
    if (!cfg.autoNext) return;
    toast('本节完成，3 秒后进入下一节');
    setTimeout(function () { goNext(0); }, 3000);
  }

  function findLinkByText(re) {
    var cands = document.querySelectorAll('a, button, .btn, span, div');
    for (var i = 0; i < cands.length; i++) {
      var el = cands[i];
      if (el.children.length > 2) continue;
      var t = (el.innerText || '').trim();
      if (!t || t.length > 14) continue;
      if (re.test(t)) return el;
    }
    return null;
  }

  // 下一节：目录解析重试 3 次 -> 兜底点"返回课程列表" -> 最后自动刷新
  function goNext(attempt) {
    if (nextLesson()) return;
    if (attempt < 2) {
      setState('未找到下一节，重试 ' + (attempt + 1) + '/3', '#854F0B');
      setTimeout(function () { goNext(attempt + 1); }, 2500);
      return;
    }
    var back = findLinkByText(/返回课程列表|返回列表|我的课程|课程目录|继续学习|返回课程/);
    if (back) { log('兜底：点击返回课程列表'); back.click(); return; }
    if (cfg.autoReload) { autoReload('未找到下一节'); return; }
    setState('已到最后一节', '#854F0B');
    toast('本页目录已学完');
  }

  var reloading = false;
  function autoReload(reason) {
    if (reloading) return;
    var cnt = 0;
    try { cnt = parseInt(sessionStorage.getItem('eas_reload') || '0', 10) || 0; } catch (e) {}
    if (cnt >= 3) {
      reloading = true;
      setState('刷新 3 次仍失败，已停手', '#A32D2D');
      toast('本页已自动刷新 3 次仍未恢复，停止自救（可手动刷新继续）');
      return;
    }
    reloading = true;
    try { sessionStorage.setItem('eas_reload', String(cnt + 1)); } catch (e) {}
    toast(reason + '，自动刷新 ' + (cnt + 1) + '/3');
    setTimeout(function () { location.reload(); }, 1500);
  }

  // 列表页闭环：没有视频时，8 秒后自动点"继续学习"进入未完成课程
  var pageLoadAt = Date.now(), enteredOnce = false, lastEnterTry = 0;
  function tryEnterCourse() {
    if (!cfg.autoEnter || enteredOnce) return;
    if (Date.now() - pageLoadAt < 8000) return;
    if (Date.now() - lastEnterTry < 5000) return;
    lastEnterTry = Date.now();
    var el = findLinkByText(/^(继续学习|开始学习|去学习|进入学习|继续观看|继续听课)$/);
    if (el) {
      enteredOnce = true;
      log('当前页无视频，自动进入未完成课程');
      toast('自动进入未完成课程');
      try { el.click(); } catch (e) {}
    }
  }

  function tick() {
    // 答题优先：弹窗可能覆盖视频，甚至整页没有 video
    if (cfg.autoAnswer) {
      try { tryAnswer(); } catch (e) { log('答题异常', e.message); }
    }

    var v = findVideo();
    if (!v) {
      tryEnterCourse();
      setState('未检测到视频', '#5F5E5A');
      setProg('--');
      return;
    }
    // 换视频（新元素或换源）时重新接管，避免 SPA 切课后 handled 未复位
    if (v !== video || v.__easSrc !== (v.currentSrc || v.src || '')) bindVideo(v);

    if (cfg.mute) { v.muted = true; v.volume = 0; }
    if (v.playbackRate !== cfg.rate) { try { v.playbackRate = cfg.rate; } catch (e) {} }
    if (cfg.autoDialog) closeDialogs();

    var dur = v.duration || 0, ct = v.currentTime || 0;
    setProg(dur ? fmt(ct) + ' / ' + fmt(dur) + '  (' + Math.floor(ct / dur * 100) + '%)' : fmt(ct));

    if (!v.ended && dur && ct >= dur - 1.2) { onEnded(); return; }
    if (v.ended) { onEnded(); return; }

    if (v.paused) {
      // 答题弹窗打开时视频本就该暂停，别去抢
      if (cfg.autoAnswer && findQuizDialog(true)) {
        setState('答题中，等待提交', '#185FA5');
        lastT = ct;
        return;
      }
      setState('已暂停，正在恢复', '#854F0B');
      v.play().catch(function () {});
      return;
    }

    if (Math.abs(ct - lastT) < 0.05) {
      stall++;
      if (stall === 15) { try { v.currentTime = ct + 0.5; } catch (e) {} log('播放停滞，尝试续播'); }
      if (stall === 40) { try { v.currentTime = ct + 2; v.play().catch(function () {}); } catch (e) {} log('二次自救：向前跳跃续播'); }
      if (stall > 45) setState('卡住，准备自动刷新', '#A32D2D');
      if (stall >= 90 && cfg.autoReload) autoReload('视频长时间无进展');
    } else {
      stall = 0;
      if (ct > 30) { try { sessionStorage.removeItem('eas_reload'); } catch (e) {} }
    }
    lastT = ct;
    setState('播放中', '#276749');
  }

  function fmt(sec) {
    sec = Math.max(0, Math.floor(sec || 0));
    var h = Math.floor(sec / 3600), m = Math.floor(sec % 3600 / 60), s = sec % 60;
    var p = function (n) { return n < 10 ? '0' + n : '' + n; };
    return (h ? h + ':' : '') + p(m) + ':' + p(s);
  }

  /* ===================== 面板 UI ===================== */
  var elState = null, elProg = null, panel = null;

  function setState(text, color) {
    if (!elState) return;
    elState.textContent = text;
    elState.style.color = color || '#2C2C2A';
  }
  function setProg(text) { if (elProg) elProg.textContent = text; }

  function toast(msg) {
    var box = document.getElementById('eas-toast');
    if (!box) {
      box = document.createElement('div');
      box.id = 'eas-toast';
      document.body.appendChild(box);
    }
    box.textContent = msg;
    box.className = 'eas-toast eas-toast-show';
    clearTimeout(box.__t);
    box.__t = setTimeout(function () { box.className = 'eas-toast'; }, 3200);
  }

  function buildPanel() {
    GM_addStyle([
      '.eas-panel{position:fixed;right:24px;bottom:24px;z-index:2147483000;width:248px;background:#fff;',
      'border:1px solid #e2e8f0;border-radius:12px;box-shadow:0 6px 24px rgba(0,0,0,.12);',
      'font:13px/1.6 -apple-system,"Segoe UI","Microsoft YaHei",sans-serif;color:#2C2C2A;user-select:none}',
      '.eas-head{display:flex;align-items:center;justify-content:space-between;padding:10px 14px;',
      'border-bottom:1px solid #edf2f7;cursor:move;font-weight:500;font-size:14px}',
      '.eas-fold{cursor:pointer;color:#888780;padding:0 4px}',
      '.eas-body{padding:12px 14px}',
      '.eas-row{display:flex;align-items:center;justify-content:space-between;margin-bottom:8px}',
      '.eas-row span{color:#5F5E5A;font-size:12px}',
      '.eas-row b{font-weight:500;font-size:12px;text-align:right;max-width:150px}',
      '.eas-panel select{padding:3px 6px;border:1px solid #e2e8f0;border-radius:6px;font-size:12px}',
      '.eas-check{display:block;margin:6px 0;font-size:12px;color:#444441;cursor:pointer}',
      '.eas-check input{margin-right:6px;vertical-align:-1px}',
      '.eas-btns{display:flex;gap:8px;margin-top:10px}',
      '.eas-btns button{flex:1;padding:7px 0;border:none;border-radius:7px;background:#3182ce;color:#fff;',
      'font-size:12px;cursor:pointer}',
      '.eas-btns button.ghost{background:#edf2f7;color:#444441}',
      '.eas-btns button:hover{opacity:.88}',
      '.eas-tip{margin:10px 0 0;font-size:11px;color:#888780;line-height:1.5}',
      '.eas-toast{position:fixed;left:50%;bottom:80px;transform:translate(-50%,12px);z-index:2147483001;',
      'background:rgba(26,32,44,.92);color:#fff;padding:10px 18px;border-radius:8px;font-size:13px;',
      'opacity:0;pointer-events:none;transition:all .25s}',
      '.eas-toast-show{opacity:1;transform:translate(-50%,0)}'
    ].join(''));

    panel = document.createElement('div');
    panel.className = 'eas-panel';
    panel.id = 'eas-panel';
    panel.innerHTML = [
      '<div class="eas-head" id="eas-head"><span>看课助手</span><span class="eas-fold" id="eas-fold">—</span></div>',
      '<div class="eas-body" id="eas-body">',
      '<div class="eas-row"><span>状态</span><b id="eas-state">启动中…</b></div>',
      '<div class="eas-row"><span>进度</span><b id="eas-prog">--</b></div>',
      '<div class="eas-row"><span>倍速</span><select id="eas-rate">',
      '<option value="1">1.0x</option><option value="1.25">1.25x</option>',
      '<option value="1.5">1.5x</option><option value="2">2.0x</option></select></div>',
      '<label class="eas-check"><input type="checkbox" id="eas-next">播完自动下一节</label>',
      '<label class="eas-check"><input type="checkbox" id="eas-answer">自动答题（答错也继续）</label>',
      '<label class="eas-check"><input type="checkbox" id="eas-verify">拦截验证请求</label>',
      '<label class="eas-check"><input type="checkbox" id="eas-dialog">自动关闭提示弹窗</label>',
      '<label class="eas-check"><input type="checkbox" id="eas-reload">卡死自动刷新</label>',
      '<label class="eas-check"><input type="checkbox" id="eas-enter">列表页自动进课</label>',
      '<label class="eas-check"><input type="checkbox" id="eas-mute">静音播放</label>',
      '<div class="eas-btns"><button id="eas-play">播放/继续</button>',
      '<button id="eas-skip" class="ghost">下一节</button></div>',
      '<p class="eas-tip">全自动：拿不到答案时按选项轮换穷举，不必人工干预。倍速可能被判无效学时，建议先 1.0x 跑通。</p>',
      '</div>'
    ].join('');
    document.body.appendChild(panel);

    elState = document.getElementById('eas-state');
    elProg = document.getElementById('eas-prog');

    var rate = document.getElementById('eas-rate');
    rate.value = String(cfg.rate);
    rate.onchange = function () { cfg.rate = parseFloat(rate.value) || 1; saveCfg(); if (video) { try { video.playbackRate = cfg.rate; } catch (e) {} } };

    bindCheck('eas-next', 'autoNext');
    bindCheck('eas-answer', 'autoAnswer');
    bindCheck('eas-verify', 'blockVerify');
    bindCheck('eas-dialog', 'autoDialog');
    bindCheck('eas-reload', 'autoReload');
    bindCheck('eas-enter', 'autoEnter');
    bindCheck('eas-mute', 'mute');

    document.getElementById('eas-play').onclick = function () {
      var v = findVideo();
      if (!v) { toast('当前页面没有视频'); return; }
      if (cfg.mute) { v.muted = true; v.volume = 0; }
      v.play().then(function () { toast('已开始播放'); }).catch(function () { toast('播放被浏览器拦截，请点一下页面再试'); });
    };
    document.getElementById('eas-skip').onclick = function () {
      if (!nextLesson()) toast('没找到下一节');
    };

    var body = document.getElementById('eas-body');
    document.getElementById('eas-fold').onclick = function (e) {
      e.stopPropagation();
      var hidden = body.style.display === 'none';
      body.style.display = hidden ? '' : 'none';
      this.textContent = hidden ? '—' : '+';
    };

    // 拖动
    var head = document.getElementById('eas-head');
    var dragging = false, sx = 0, sy = 0, ox = 0, oy = 0;
    head.addEventListener('mousedown', function (e) {
      if (e.target.id === 'eas-fold') return;
      dragging = true;
      sx = e.clientX; sy = e.clientY;
      var r = panel.getBoundingClientRect();
      ox = r.left; oy = r.top;
      panel.style.right = 'auto'; panel.style.bottom = 'auto';
      panel.style.left = ox + 'px'; panel.style.top = oy + 'px';
      e.preventDefault();
    });
    document.addEventListener('mousemove', function (e) {
      if (!dragging) return;
      panel.style.left = Math.max(0, Math.min(window.innerWidth - 60, ox + e.clientX - sx)) + 'px';
      panel.style.top = Math.max(0, Math.min(window.innerHeight - 40, oy + e.clientY - sy)) + 'px';
    });
    document.addEventListener('mouseup', function () { dragging = false; });
  }
  function bindCheck(id, key) {
    var el = document.getElementById(id);
    el.checked = !!cfg[key];
    el.onchange = function () { cfg[key] = el.checked; saveCfg(); };
  }

  /* ===================== 启动 ===================== */
  function boot() {
    installFetchHook();
    buildPanel();
    setState('等待视频…', '#5F5E5A');
    tick();
    setInterval(tick, 1000);
    log('已启动，无广告 / 无授权 / 无外部请求');
  }

  if (document.readyState === 'loading') {
    document.addEventListener('DOMContentLoaded', boot, { once: true });
  } else {
    boot();
  }
})();