// ==UserScript==
// @name [YIT]-刷课助手
// @version 2.0.1
// @author adapted
// @license MIT
// @description 燕京理工学院(yit.haiqikeji.com)在线学习平台刷课助手 — 自动播放视频、自动下一节、进度追踪
// @match *://*.haiqikeji.com/*
// @run-at document-end
// @grant unsafeWindow
// @grant GM_setValue
// @grant GM_getValue
// ==/UserScript==

(function() {
    'use strict';

    /********************************* 配置 ****************************************/
    var CONFIG = {
        videoRate: 1,
        autoNext: true,
        nextDelay: 3,
        showBox: true,
        debug: true
    };

    // 从 localStorage 加载
    ['videoRate','autoNext','nextDelay','showBox'].forEach(function(k) {
        var v = localStorage.getItem('yit_' + k);
        if (v !== null) {
            if (v === 'true') CONFIG[k] = true;
            else if (v === 'false') CONFIG[k] = false;
            else { var n = parseFloat(v); CONFIG[k] = !isNaN(n) ? n : v; }
        }
    });

    function saveConfig(key, value) {
        CONFIG[key] = value;
        localStorage.setItem('yit_' + key, value);
    }

    /********************************* 工具 ****************************************/
    function formatTime(s) {
        if (!s || s < 0) return '00:00';
        s = Math.floor(s);
        var h = Math.floor(s/3600), m = Math.floor((s%3600)/60), sec = s%60;
        var pad = function(n){return n<10?'0'+n:''+n;};
        return (h>0?pad(h)+':':'') + pad(m) + ':' + pad(sec);
    }

    function dlog(msg, color) {
        if (!CONFIG.debug && color !== 'red' && color !== 'green') return;
        var t = new Date().toLocaleTimeString();
        console.log('[YIT '+t+']', msg);
        try {
            var el = document.getElementById('yit-log');
            if (el) {
                var div = document.createElement('div');
                div.innerHTML = '<span style="color:'+(color||'#555')+';font-size:11px;">['+t+'] '+msg+'</span>';
                el.insertBefore(div, el.firstChild);
                if (el.children.length > 200) el.removeChild(el.lastChild);
            }
        } catch(e) {}
    }

    /********************************* UI ****************************************/
    function buildPanel() {
        if (!CONFIG.showBox || document.getElementById('yit-box')) return;
        var html = '\
<div id="yit-box" style="position:fixed;top:10px;right:10px;width:330px;max-height:520px;background:rgba(255,255,255,0.97);border-radius:10px;z-index:2147483647;font-family:system-ui,sans-serif;box-shadow:0 4px 20px rgba(0,0,0,0.2);display:flex;flex-direction:column;overflow:hidden;font-size:13px;">\
  <div id="yit-header" style="background:#1677ff;color:#fff;padding:8px 14px;display:flex;justify-content:space-between;align-items:center;cursor:move;user-select:none;">\
    <span style="font-weight:bold;">YIT 刷课助手 v2</span>\
    <span id="yit-min" style="cursor:pointer;font-size:18px;line-height:1;" title="最小化">_</span>\
  </div>\
  <div id="yit-body" style="padding:10px 14px;overflow-y:auto;flex:1;">\
    <div style="margin-bottom:6px;display:flex;align-items:center;gap:8px;">\
      <label style="flex:1;font-size:12px;">倍速</label>\
      <select id="yit-rate" style="padding:3px 8px;border-radius:4px;border:1px solid #d9d9d9;font-size:12px;">\
        <option value="1" selected>1x</option><option value="1.5">1.5x</option><option value="2">2x</option>\
        <option value="3">3x</option><option value="4">4x</option><option value="8">8x</option><option value="16">16x</option>\
      </select>\
    </div>\
    <div style="margin-bottom:6px;display:flex;align-items:center;gap:8px;">\
      <label style="flex:1;font-size:12px;">自动下一节</label>\
      <input type="checkbox" id="yit-autonext" __CHECKED__ style="width:16px;height:16px;">\
    </div>\
    <div style="margin-bottom:8px;display:flex;align-items:center;gap:8px;">\
      <label style="flex:1;font-size:12px;">跳转等待(秒)</label>\
      <input type="number" id="yit-delay" value="__DELAY__" min="0" max="30" style="width:50px;padding:3px 6px;border-radius:4px;border:1px solid #d9d9d9;font-size:12px;">\
    </div>\
    <div style="margin-bottom:8px;display:flex;gap:4px;">\
      <button id="yit-detect" style="flex:1;padding:5px 2px;background:#1677ff;color:#fff;border:none;border-radius:6px;cursor:pointer;font-size:11px;">扫描</button>\
      <button id="yit-next" style="flex:1;padding:5px 2px;background:#52c41a;color:#fff;border:none;border-radius:6px;cursor:pointer;font-size:11px;">下一节</button>\
      <button id="yit-debug-btn" style="flex:1;padding:5px 2px;background:#fa8c16;color:#fff;border:none;border-radius:6px;cursor:pointer;font-size:11px;">调试</button>\
    </div>\
    <div id="yit-progress-section" style="margin-bottom:8px;">\
      <div style="display:flex;justify-content:space-between;align-items:center;margin-bottom:2px;">\
        <span id="yit-vname" style="font-size:11px;color:#333;max-width:220px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;">等待视频...</span>\
        <span id="yit-pct" style="font-size:12px;font-weight:bold;color:#1677ff;">0%</span>\
      </div>\
      <div style="width:100%;height:8px;background:#e8e8e8;border-radius:4px;overflow:hidden;">\
        <div id="yit-bar" style="width:0%;height:100%;background:linear-gradient(90deg,#1677ff,#52c41a);border-radius:4px;transition:width 0.3s;"></div>\
      </div>\
      <div style="display:flex;justify-content:space-between;margin-top:2px;">\
        <span id="yit-cur" style="font-size:10px;color:#999;">00:00</span>\
        <span id="yit-remain" style="font-size:10px;color:#999;">剩余 --:--</span>\
        <span id="yit-total" style="font-size:10px;color:#999;">00:00</span>\
      </div>\
    </div>\
    <div id="yit-status" style="background:#f6ffed;border:1px solid #b7eb8f;border-radius:6px;padding:6px 10px;margin-bottom:8px;font-size:12px;min-height:20px;">\
      就绪 - 等待视频加载...\
    </div>\
    <div id="yit-log" style="max-height:150px;overflow-y:auto;font-size:11px;color:#555;border-top:1px solid #eee;padding-top:4px;"></div>\
  </div>\
</div>';
        html = html.replace('__CHECKED__', CONFIG.autoNext ? 'checked' : '');
        html = html.replace('__DELAY__', CONFIG.nextDelay);
        var div = document.createElement('div');
        div.innerHTML = html;
        document.body.appendChild(div.firstElementChild);

        // 事件绑定
        document.getElementById('yit-rate').value = CONFIG.videoRate;
        document.getElementById('yit-rate').addEventListener('change', function(){
            saveConfig('videoRate', parseFloat(this.value));
            applyRateToAll();
            dlog('倍速 = '+CONFIG.videoRate+'x','blue');
        });

        document.getElementById('yit-autonext').addEventListener('change', function(){
            saveConfig('autoNext', this.checked);
            dlog('自动下一节: '+(CONFIG.autoNext?'开':'关'),'blue');
        });

        document.getElementById('yit-delay').addEventListener('change', function(){
            saveConfig('nextDelay', parseInt(this.value)||3);
            dlog('跳转等待: '+CONFIG.nextDelay+'s','blue');
        });

        document.getElementById('yit-detect').addEventListener('click', function(){
            dlog('手动扫描视频...','blue');
            scanAllVideos();
        });

        document.getElementById('yit-next').addEventListener('click', function(){
            dlog('手动跳转下一节','blue');
            resetProgress();
            clickNext();
        });

        document.getElementById('yit-debug-btn').addEventListener('click', function(){
            dlog('运行调试...','blue');
            unsafeWindow.yitDebug();
        });

        // 最小化
        var min = false;
        document.getElementById('yit-min').addEventListener('click', function(){
            var b = document.getElementById('yit-body');
            min = !min;
            b.style.display = min ? 'none' : '';
            this.textContent = min ? '□' : '_';
        });

        // 拖拽
        (function(){
            var hdr = document.getElementById('yit-header');
            var box = document.getElementById('yit-box');
            var d = false, ox, oy;
            hdr.addEventListener('mousedown', function(e){ d=true; ox=e.clientX-box.offsetLeft; oy=e.clientY-box.offsetTop; });
            document.addEventListener('mousemove', function(e){ if(!d)return; box.style.left=(e.clientX-ox)+'px'; box.style.top=(e.clientY-oy)+'px'; box.style.right='auto'; });
            document.addEventListener('mouseup', function(){ d=false; });
        })();
    }

    /********************************* 视频处理核心 ****************************************/

    // 递归搜索所有 video 元素（包括 iframe 和 shadow DOM）
    function findAllVideos(root) {
        root = root || document;
        var videos = [];

        // 直接查找
        try {
            var direct = root.querySelectorAll('video');
            for (var i = 0; i < direct.length; i++) videos.push(direct[i]);
        } catch(e) {}

        // 搜索 iframe
        try {
            var iframes = root.querySelectorAll('iframe');
            for (var i = 0; i < iframes.length; i++) {
                try {
                    var doc = iframes[i].contentDocument || iframes[i].contentWindow.document;
                    if (doc) {
                        var fv = doc.querySelectorAll('video');
                        for (var j = 0; j < fv.length; j++) videos.push(fv[j]);
                        // 递归iframe内iframe
                        var nested = findAllVideos(doc);
                        for (var k = 0; k < nested.length; k++) videos.push(nested[k]);
                    }
                } catch(e) {
                    // 跨域 iframe 无法访问
                }
            }
        } catch(e) {}

        // 搜索 shadow DOM
        try {
            var allEls = root.querySelectorAll('*');
            for (var m = 0; m < allEls.length; m++) {
                if (allEls[m].shadowRoot) {
                    var sv = allEls[m].shadowRoot.querySelectorAll('video');
                    for (var n = 0; n < sv.length; n++) videos.push(sv[n]);
                }
            }
        } catch(e) {}

        return videos;
    }

    function applyRateToAll() {
        var videos = findAllVideos();
        videos.forEach(function(v) {
            try { v.playbackRate = CONFIG.videoRate; } catch(e) {}
        });
    }

    function updateStatus(msg) {
        var el = document.getElementById('yit-status');
        if (el) el.textContent = msg;
    }

    function resetProgress(videoInfo) {
        var bar = document.getElementById('yit-bar');
        var pctEl = document.getElementById('yit-pct');
        var curEl = document.getElementById('yit-cur');
        var remainEl = document.getElementById('yit-remain');
        var totalEl = document.getElementById('yit-total');
        var vnameEl = document.getElementById('yit-vname');
        if (bar) bar.style.width = '0%';
        if (pctEl) pctEl.textContent = '0%';
        if (curEl) curEl.textContent = '00:00';
        if (vnameEl) vnameEl.textContent = (videoInfo && videoInfo.name) || '加载中...';
        if (totalEl) totalEl.textContent = (videoInfo && videoInfo.durStr) || '--:--';
        if (remainEl) remainEl.textContent = (videoInfo && videoInfo.durStr) ? '剩余 ' + videoInfo.durStr : '剩余 --:--';
    }

    // 快速获取新视频信息（不等播放就开始显示时长）
    function quickVideoInfo() {
        var videos = findAllVideos();
        if (videos.length > 0) {
            var v = videos[0];
            var dur = v.duration;
            var durStr = (!isNaN(dur) && dur > 0) ? formatTime(dur) : null;
            var name = '';
            try { name = (document.title || '').replace(/\s*[-_|]\s*.+$/, '').substring(0, 40) || '视频'; } catch(e) {}
            if (durStr || name) {
                return { name: name, durStr: durStr };
            }
        }
        return null;
    }

    // 记录已处理的视频（用弱引用避免内存问题）
    var handledVideos = new WeakSet();

    var skipMode = false; // 是否在跳过已完成视频的模式中

    function processVideo(video) {
        if (handledVideos.has(video)) return;
        handledVideos.add(video);

        // ★ 关键：播放前先检查是否已完成
        if (isCurrentItemCompleted()) {
            dlog('⏭️ 当前视频已完成，跳过播放', 'green');
            updateStatus('已完成，跳过 → 下一节');
            skipMode = true;
            if (CONFIG.autoNext) {
                setTimeout(function() {
                    resetProgress();
                    clickNext();
                }, 1000);
            }
            return;
        }

        skipMode = false;
        var dur = video.duration;
        var durStr = isNaN(dur) ? '未知' : formatTime(dur);
        dlog('发现未完成视频 | 时长:' + durStr + ' | readyState:' + video.readyState, 'green');

        // 等待视频元数据加载
        function onLoaded() {
            dlog('视频元数据就绪 | 时长:' + formatTime(video.duration), 'green');
            startPlayback(video);
        }

        if (video.readyState >= 2) {
            startPlayback(video);
        } else {
            video.addEventListener('loadedmetadata', onLoaded, { once: true });
            video.addEventListener('loadeddata', function(){
                if (video.readyState >= 2) startPlayback(video);
            }, { once: true });
            setTimeout(function(){
                if (!video.dataset.yitPlaying) startPlayback(video);
            }, 5000);
        }
    }

    function startPlayback(video) {
        if (video.dataset.yitPlaying) return;

        // ★ 再次确认未完成才播放
        if (isCurrentItemCompleted()) {
            dlog('⏭️ 二次确认已完成，跳过播放', 'green');
            if (CONFIG.autoNext) {
                setTimeout(function() { resetProgress(); clickNext(); }, 1000);
            }
            return;
        }

        video.dataset.yitPlaying = '1';
        var myGen = yitGeneration; // 记录此监听器所属世代，防止旧监听器更新UI

        var durStr = formatTime(video.duration) || '未知';

        // 设置倍速
        video.playbackRate = CONFIG.videoRate;
        video.muted = true;

        // 移除视频上的点击事件阻止
        video.style.pointerEvents = 'auto';

        // 提取视频标题
        var vname = '';
        try {
            var pageTitle = document.title || '';
            vname = pageTitle.replace(/\s*[-_|]\s*.+$/, '').substring(0, 40) || '视频';
            var vnameEl = document.getElementById('yit-vname');
            if (vnameEl) vnameEl.textContent = vname;
        } catch(e) {}

        // 尝试播放
        var playPromise = video.play();
        if (playPromise && playPromise.then) {
            playPromise.then(function() {
                dlog('播放成功 ('+CONFIG.videoRate+'x) | 时长:'+durStr, 'green');
                updateStatus('播放中 | ' + CONFIG.videoRate + 'x');
            }).catch(function(err) {
                dlog('自动播放失败: '+err.message, 'orange');
                updateStatus('等待用户交互...');
                // 监听用户交互来触发播放
                var resume = function() {
                    video.play().then(function(){
                        dlog('用户交互后播放成功', 'green');
                    }).catch(function(){});
                    document.removeEventListener('click', resume);
                    document.removeEventListener('keydown', resume);
                };
                document.addEventListener('click', resume, { once: true });
                document.addEventListener('keydown', resume, { once: true });
                // 模拟点击视频区域
                try {
                    video.click();
                    video.dispatchEvent(new MouseEvent('click', { bubbles: true }));
                } catch(e) {}
            });
        }

        // 实时进度条更新
        video.addEventListener('timeupdate', function() {
            if (yitGeneration !== myGen) return; // 旧世代监听器，忽略
            var cur = video.currentTime;
            var d = video.duration; // ★ 始终读取实时duration，不捕获闭包变量
            if (!d || isNaN(d) || d <= 0) return;
            var pct = Math.min(100, Math.round(cur / d * 100));
            var remain = Math.max(0, d - cur);

            var bar = document.getElementById('yit-bar');
            var pctEl = document.getElementById('yit-pct');
            var curEl = document.getElementById('yit-cur');
            var remainEl = document.getElementById('yit-remain');
            var totalEl = document.getElementById('yit-total');

            if (bar) bar.style.width = pct + '%';
            if (pctEl) pctEl.textContent = pct + '%';
            if (curEl) curEl.textContent = formatTime(cur);
            if (remainEl) remainEl.textContent = '剩余 ' + formatTime(remain);
            if (totalEl) totalEl.textContent = formatTime(d);
        });

        // 监听倍速被页面重置
        video.addEventListener('ratechange', function() {
            if (yitGeneration !== myGen) return;
            if (video.playbackRate !== CONFIG.videoRate && video.dataset.yitPlaying) {
                dlog('倍速被重置为 '+video.playbackRate+'x，已恢复', 'orange');
                video.playbackRate = CONFIG.videoRate;
            }
        });

        // 监听暂停
        video.addEventListener('pause', function() {
            if (yitGeneration !== myGen) return;
            if (video.dataset.yitPlaying && !video.ended) {
                dlog('视频被暂停，尝试恢复...', 'orange');
                setTimeout(function(){
                    if (yitGeneration !== myGen) return;
                    if (video.dataset.yitPlaying && video.paused && !video.ended) {
                        video.play().catch(function(){});
                    }
                }, 500);
            }
        });

        function doJump() {
            resetProgress();
            updateStatus('跳转中...');
            clickNext();
        }

        function onVideoComplete() {
            if (video.dataset.yitCompleted) return;
            video.dataset.yitCompleted = '1';
            video.dataset.yitPlaying = '0';
            dlog('视频播放完成!', 'green');
            updateStatus('已完成，' + CONFIG.nextDelay + '秒后跳转');
            var bar = document.getElementById('yit-bar');
            var pctEl = document.getElementById('yit-pct');
            var remainEl = document.getElementById('yit-remain');
            if (bar) bar.style.width = '100%';
            if (pctEl) pctEl.textContent = '100%';
            if (remainEl) remainEl.textContent = '剩余 00:00';
            if (CONFIG.autoNext) {
                dlog(CONFIG.nextDelay+'秒后跳转下一节...', 'blue');
                setTimeout(doJump, CONFIG.nextDelay * 1000);
            } else {
                dlog('自动下一节关闭中，请手动点击', 'orange');
            }
        }

        // 把完成回调挂到 video 元素上，供外部兜底检测调用
        video._yitComplete = onVideoComplete;

        // 监听结束
        video.addEventListener('ended', function() {
            if (yitGeneration !== myGen) return;
            dlog('[ended事件触发]', 'green');
            onVideoComplete();
        });

        // 监听卡顿/等待
        video.addEventListener('waiting', function() {
            if (yitGeneration !== myGen) return;
            dlog('视频缓冲中...', 'orange');
        });
        video.addEventListener('canplay', function() {
            if (yitGeneration !== myGen) return;
            if (video.paused && video.dataset.yitPlaying && !video.ended) {
                video.play().catch(function(){});
            }
        });
    }

    function scanAllVideos() {
        var videos = findAllVideos();
        dlog('扫描到 ' + videos.length + ' 个 video 元素', videos.length > 0 ? 'green' : 'orange');
        videos.forEach(processVideo);

        // 打印 iframe 信息帮助调试
        var iframes = document.querySelectorAll('iframe');
        if (iframes.length > 0) {
            dlog('页面有 ' + iframes.length + ' 个iframe', 'blue');
            iframes.forEach(function(f, i) {
                try {
                    var doc = f.contentDocument || f.contentWindow.document;
                    if (doc) {
                        var vids = doc.querySelectorAll('video');
                        dlog('  iframe['+i+']: ' + vids.length + '个video, url=' + (f.src||'about:blank').substring(0,80), 'blue');
                    }
                } catch(e) {
                    dlog('  iframe['+i+']: 跨域无法访问 (' + (f.src||'about:blank').substring(0,60) + ')', 'orange');
                }
            });
        }

        if (videos.length === 0 && iframes.length === 0) {
            dlog('未找到视频。页面可能使用canvas/其他方式播放。请截图发给我调试。', 'red');
        }
    }

    /********************************* 完成状态检测 ****************************************/

    // 检测当前视频/课程项是否已标记为完成
    // 策略：检查页面 DOM 中各种可能的"已完成"标识
    function isCurrentItemCompleted() {
        // 在section-item结构中查找当前正在播放/激活的节，看它是否已完成
        var activeItem = null;
        var activeClasses = ['active', 'is-active', 'current', 'selected', 'is-playing', 'playing'];
        for (var c = 0; c < activeClasses.length; c++) {
            activeItem = document.querySelector('.section-item.' + activeClasses[c]) ||
                         document.querySelector('.section-item[class*="' + activeClasses[c] + '"]');
            if (activeItem) break;
        }

        if (!activeItem) return false;

        // 检查激活项内部是否有完成标识
        // 1. class中含completed/done/finish/checked/success
        if (/completed|done|finish|checked|success|passed|watched/i.test(activeItem.className)) {
            dlog('完成检测: section-item class=' + activeItem.className, 'blue');
            return true;
        }
        // 2. 内部有勾图标
        var checkIcon = activeItem.querySelector('[class*="check"], [class*="success"], [class*="finish"], [class*="complete"], [class*="done"], .el-icon-check, .anticon-check');
        if (checkIcon) {
            dlog('完成检测: 找到完成图标', 'blue');
            return true;
        }
        // 3. 有"已完成""已观看"文字
        var text = activeItem.textContent || '';
        if (/已完成|已观看|已通过|已学完/.test(text)) {
            dlog('完成检测: 找到已完成文字', 'blue');
            return true;
        }
        // 4. 视频已播放到100%且ended
        var vids = findAllVideos();
        for (var v = 0; v < vids.length; v++) {
            if (vids[v].ended || (vids[v].duration > 0 && vids[v].currentTime >= vids[v].duration - 1)) {
                dlog('完成检测: video已结束', 'blue');
                return true;
            }
        }
        return false;
    }
    // 基于页面实际DOM结构的导航
    // 结构: .chapter > .chapter-sections > .section-item (多个) > .section-header > .section-title
    function clickNext() {
        // 策略1: 找到当前激活的section-item，点下一个
        function tryActiveSectionNext() {
            // 查找带有激活状态的section-item
            var activeClasses = ['active', 'is-active', 'current', 'selected', 'is-playing', 'playing'];
            var activeItem = null;
            for (var c = 0; c < activeClasses.length; c++) {
                activeItem = document.querySelector('.section-item.' + activeClasses[c]) ||
                             document.querySelector('.section-item[class*="' + activeClasses[c] + '"]');
                if (activeItem) break;
            }
            if (activeItem) {
                dlog('找到激活节: ' + (activeItem.textContent||'').substring(0,30).replace(/\s/g,''), 'blue');
                var nxt = activeItem.nextElementSibling;
                // 跳过非section-item的兄弟
                while (nxt && !nxt.classList.contains('section-item')) {
                    nxt = nxt.nextElementSibling;
                }
                if (nxt && nxt.classList.contains('section-item')) {
                    dlog('→ 下一节: ' + (nxt.textContent||'').substring(0,30).replace(/\s/g,''), 'green');
                    nxt.click();
                    nxt.dispatchEvent(new MouseEvent('click', { bubbles: true }));
                    return true;
                }
                // 当前是章内最后一节，找下一章的第一个section-item
                var parentChapter = activeItem.closest('.chapter');
                if (parentChapter) {
                    var nextChapter = parentChapter.nextElementSibling;
                    while (nextChapter && !nextChapter.classList.contains('chapter')) {
                        nextChapter = nextChapter.nextElementSibling;
                    }
                    if (nextChapter && nextChapter.classList.contains('chapter')) {
                        var firstSection = nextChapter.querySelector('.section-item');
                        if (firstSection) {
                            dlog('→ 下一章第一节: ' + (firstSection.textContent||'').substring(0,30).replace(/\s/g,''), 'green');
                            firstSection.click();
                            firstSection.dispatchEvent(new MouseEvent('click', { bubbles: true }));
                            return true;
                        }
                    }
                }
            }
            return null;
        }

        // 策略2: 找到页面上所有section-item，找匹配当前页面标题的，点下一个
        function trySectionByTitle() {
            var pageTitle = (document.title || '').replace(/\s+/g, '').substring(0,30);
            var items = document.querySelectorAll('.section-item');
            for (var i = 0; i < items.length; i++) {
                var itemTitle = (items[i].textContent || '').replace(/\s+/g, '').substring(0,30);
                if (itemTitle && pageTitle && pageTitle.indexOf(itemTitle) !== -1 || itemTitle.indexOf(pageTitle) !== -1) {
                    dlog('通过标题匹配到当前节: ' + itemTitle, 'blue');
                    var nxt = items[i].nextElementSibling;
                    while (nxt && !nxt.classList.contains('section-item')) {
                        nxt = nxt.nextElementSibling;
                    }
                    if (nxt && nxt.classList.contains('section-item')) {
                        dlog('→ 下一节: ' + (nxt.textContent||'').substring(0,30).replace(/\s/g,''), 'green');
                        nxt.click();
                        nxt.dispatchEvent(new MouseEvent('click', { bubbles: true }));
                        return true;
                    }
                    // 跨章
                    var ch = items[i].closest('.chapter');
                    if (ch) {
                        var nch = ch.nextElementSibling;
                        while (nch && !nch.classList.contains('chapter')) nch = nch.nextElementSibling;
                        if (nch) {
                            var fs = nch.querySelector('.section-item');
                            if (fs) {
                                dlog('→ 下一章: ' + (fs.textContent||'').substring(0,30).replace(/\s/g,''), 'green');
                                fs.click();
                                fs.dispatchEvent(new MouseEvent('click', { bubbles: true }));
                                return true;
                            }
                        }
                    }
                }
            }
            return null;
        }

        // 策略3: 文本匹配下一节按钮
        function tryTextMatch() {
            var els = document.querySelectorAll('button, a, span[class*="btn"], div[class*="btn"]');
            for (var i = 0; i < els.length; i++) {
                var b = els[i];
                if (!b.offsetParent) continue;
                var t = (b.textContent || '').replace(/\s/g, '');
                if (t && /^下一[节章课讲个步题视]$|^继续学习$|^继续$|^next$/i.test(t)) {
                    return b;
                }
            }
            return null;
        }

        // 策略4: 找箭头/下页图标
        function tryIcon() {
            var icons = document.querySelectorAll('[class*="arrow-right"], [class*="ArrowRight"], [class*="arrow_next"], [class*="next-btn"], [class*="NextBtn"]');
            for (var i = 0; i < icons.length; i++) {
                var p = icons[i].closest('button, a') || icons[i].parentElement;
                if (p && p.offsetParent) return p;
            }
            return null;
        }

        var strategies = [tryActiveSectionNext, trySectionByTitle, tryTextMatch, tryIcon];
        var strategyNames = ['激活节下一项', '标题匹配下一项', '文本匹配按钮', '图标按钮'];
        for (var i = 0; i < strategies.length; i++) {
            try {
                var result = strategies[i]();
                if (result === true) {
                    dlog('clickNext: 策略'+(i+1)+'('+strategyNames[i]+') 成功(直接跳转)', 'green');
                    updateStatus('跳转下一节...');
                    return true;
                }
                if (result && result !== true) {
                    var label = (result.textContent || result.getAttribute('aria-label') || result.className || '').substring(0, 40).replace(/\s/g, '');
                    dlog('clickNext: 策略'+(i+1)+'('+strategyNames[i]+') 点击 ['+result.tagName+'] "' + label + '"', 'green');
                    updateStatus('跳转下一节...');
                    result.click();
                    result.dispatchEvent(new MouseEvent('click', { bubbles: true, cancelable: true }));
                    return true;
                }
            } catch(e) {
                dlog('clickNext: 策略'+(i+1)+'异常: '+e.message, 'orange');
            }
        }

        dlog('clickNext: 所有策略均失败! 打印section-item:', 'red');
        var items = document.querySelectorAll('.section-item');
        items.forEach(function(it, idx) {
            dlog('  ['+idx+'] ' + (it.textContent||'').replace(/\s/g,'').substring(0,50), 'red');
        });
        updateStatus('请手动点击下一节');
        return false;
    }

    /********************************* 监听 DOM 变化 ****************************************/
    var scanTimer = null;
    var observer = new MutationObserver(function() {
        if (scanTimer) clearTimeout(scanTimer);
        scanTimer = setTimeout(function() {
            var videos = findAllVideos();
            videos.forEach(processVideo);
        }, 500);
    });

    /********************************* 视频切换检测 (URL+标题+DOM) ****************************************/
    var lastUrl = location.href;
    var lastTitle = document.title;
    var lastVideoSrc = '';
    var switchLock = false; // 防止重复触发

    var yitGeneration = 0; // 切换世代，防止旧监听器更新UI

    function onVideoSwitched() {
        if (switchLock) return;
        switchLock = true;
        setTimeout(function() { switchLock = false; }, 3000);

        dlog('检测到视频切换，重置进度并重新扫描...', 'blue');
        yitGeneration++;
        handledVideos = new WeakSet();

        // ★ 清除所有视频的播放标记（SPA可能复用video元素）
        var allVids = findAllVideos();
        allVids.forEach(function(v) {
            v.dataset.yitPlaying = '';
            v.dataset.yitCompleted = '';
        });

        // ★ 立即重置为空（不传旧视频信息，防止显示旧时长）
        resetProgress();

        // 轮询获取新视频信息（等DOM更新和新视频metadata加载）
        var pollAttempts = 0;
        function pollNewVideoInfo() {
            pollAttempts++;
            var info = quickVideoInfo();
            if (info && info.durStr) {
                resetProgress(info);
                dlog('新视频: ' + info.name + ' | 时长: ' + info.durStr, 'blue');
                return;
            }
            if (pollAttempts < 15) {
                setTimeout(pollNewVideoInfo, 400);
            } else {
                dlog('超时：未能获取新视频时长', 'orange');
            }
        }
        setTimeout(pollNewVideoInfo, 600);

        // loadedmetadata兜底（如果轮询拿到了就不再触发）
        setTimeout(function() {
            var vids = findAllVideos();
            if (vids.length > 0) {
                var v = vids[0];
                var handler = function() {
                    var ds = formatTime(v.duration);
                    if (!ds || ds === '00:00') return;
                    var el = document.getElementById('yit-total');
                    var rel = document.getElementById('yit-remain');
                    var vnameEl = document.getElementById('yit-vname');
                    if (el) el.textContent = ds;
                    if (rel) rel.textContent = '剩余 ' + ds;
                    if (vnameEl && vnameEl.textContent === '加载中...') {
                        try { vnameEl.textContent = (document.title || '').replace(/\s*[-_|]\s*.+$/, '').substring(0, 40) || '视频'; } catch(e) {}
                    }
                    dlog('视频时长已加载(metadata): ' + ds, 'blue');
                };
                if (v.readyState >= 2) {
                    // 已经加载了metadata但quickVideoInfo没拿到，直接读取
                    handler();
                } else {
                    v.addEventListener('loadedmetadata', handler, { once: true });
                }
            }
        }, 800);

        // 延迟处理完成检测和扫描
        setTimeout(function() {
            if (isCurrentItemCompleted()) {
                dlog('⏭️ 当前视频已完成，自动跳过', 'green');
                updateStatus('已完成，跳过');
                skipMode = true;
                if (CONFIG.autoNext) clickNext();
            } else {
                skipMode = false;
                updateStatus('就绪 - 等待视频加载...');
                scanAllVideos();
            }
        }, 2000);
    }

    // 检测URL变化
    setInterval(function() {
        if (location.href !== lastUrl) {
            lastUrl = location.href;
            lastTitle = document.title;
            onVideoSwitched();
        }
    }, 800);

    // 检测标题变化 (SPA内切换课程节时常改标题)
    setInterval(function() {
        var curTitle = document.title;
        if (curTitle !== lastTitle) {
            lastTitle = curTitle;
            lastUrl = location.href;
            onVideoSwitched();
        }
    }, 1500);

    // 检测video元素src变化 (同一个video元素切源)
    setInterval(function() {
        var vids = findAllVideos();
        if (vids.length > 0) {
            var curSrc = vids[0].src || vids[0].currentSrc || '';
            if (curSrc && curSrc !== lastVideoSrc) {
                lastVideoSrc = curSrc;
                onVideoSwitched();
            }
        } else {
            lastVideoSrc = '';
        }
    }, 2000);

    /********************************* 调试导出 ****************************************/
    unsafeWindow.yitDebug = function() {
        var lines = [];
        lines.push('=== YIT 调试 ===');
        lines.push('URL: ' + location.href);
        lines.push('CONFIG: ' + JSON.stringify(CONFIG));
        lines.push('');

        var videos = findAllVideos();
        lines.push('video: ' + videos.length + '个');
        videos.forEach(function(v, i) {
            lines.push('  ['+i+'] src='+(v.src||'blob')+' dur='+formatTime(v.duration)+' paused='+v.paused+' ended='+v.ended+' cur='+formatTime(v.currentTime)+' yitPlay='+v.dataset.yitPlaying+' yitDone='+v.dataset.yitCompleted);
        });
        lines.push('');

        var iframes = document.querySelectorAll('iframe');
        lines.push('iframe: ' + iframes.length + '个');
        iframes.forEach(function(f, i) {
            var info = '  ['+i+'] src=' + (f.src||'about:blank').substring(0,80);
            try { var doc = f.contentDocument||f.contentWindow.document; if(doc){ info += ' video='+doc.querySelectorAll('video').length+'个'; } } catch(e) { info += ' (跨域)'; }
            lines.push(info);
        });
        lines.push('');

        lines.push('=== 完成检测: ' + isCurrentItemCompleted() + ' ===');
        lines.push('');

        lines.push('=== 可见按钮 ===');
        var bc = 0;
        document.querySelectorAll('button, a, span[class*="btn"], div[class*="btn"]').forEach(function(b) {
            if (b.offsetParent) { var t = (b.textContent||'').replace(/\s/g,'').substring(0,30); if (t) { lines.push('  ['+b.tagName+'] "'+t+'"'); bc++; } }
        });
        if (!bc) lines.push('  (无)');
        lines.push('');

        lines.push('=== 激活状态元素 (class含active/current/selected) ===');
        var ac = 0;
        document.querySelectorAll('[class*="active"], [class*="current"], [class*="selected"]').forEach(function(el) {
            if (el.offsetParent) { var t = (el.textContent||'').replace(/\s/g,'').substring(0,60); var c = (el.className||'').replace(/\s+/g,' ').substring(0,100); lines.push('  ['+(el.tagName||'?')+'] "'+t+'" class="'+c+'"'); ac++; }
        });
        if (!ac) lines.push('  (无! 没有active/current/selected类)');
        lines.push('');

        lines.push('=== 课程列表项 (前20个) ===');
        var lc = 0;
        document.querySelectorAll('.section-item, .chapter, .chapter-title').forEach(function(el) {
            if (el.offsetParent && lc < 20) {
                var t = (el.textContent||'').replace(/\s/g,'').substring(0,60);
                var c = (el.className||'').replace(/\s+/g,' ');
                // 检查el或其子元素是否有特殊状态
                var status = '';
                // 检查自身class
                if (/completed|done|finish|checked|success|passed|watched/i.test(el.className)) status += '[自身完成]';
                // 检查子元素
                if (el.querySelector('[class*="check"], [class*="done"], [class*="finish"], [class*="complete"], [class*="success"], .el-icon-check, .anticon-check, svg')) status += '[勾]';
                if (el.querySelector('[class*="lock"], [class*="Lock"]')) status += '[锁]';
                if (el.querySelector('[class*="play"], [class*="Play"]')) status += '[播放]';
                if (status === '') status = '[无标记]';
                // 额外：检查data属性
                var ds = '';
                try { for (var dk in el.dataset) { if (el.dataset[dk]) ds += ' data-'+dk+'='+el.dataset[dk]; } } catch(e) {}
                lines.push('  ['+(el.tagName||'?')+'] '+status+' "'+t+'" class="'+c+'"'+(ds?' '+ds:''));
                lc++;
            }
        });
        lines.push('');

        lines.push('=== 页面标题/URL ===');
        lines.push('title: ' + (document.title||'?'));
        lines.push('url: ' + location.href);
        lines.push('');

        lines.push('=== 视频播放器区域 ===');
        var playerArea = document.querySelector('[class*="player"], [class*="Player"], [class*="video"], [class*="Video"], video');
        if (playerArea) {
            var pClass = (playerArea.className||'').replace(/\s+/g,' ').substring(0,80);
            var pTag = playerArea.tagName;
            var pParent = playerArea.parentElement;
            var ppClass = pParent ? (pParent.className||'').replace(/\s+/g,' ').substring(0,80) : '';
            lines.push('  播放器: <'+pTag+' class="'+pClass+'">');
            lines.push('  父元素: <'+ (pParent?pParent.tagName:'?') +' class="'+ppClass+'">');
        } else {
            lines.push('  (未找到播放器区域)');
        }
        lines.push('');

        lines.push('=== 跳转测试 ===');
        var r = clickNext();
        lines.push('clickNext: ' + (r ? 'OK' : 'FAIL'));
        lines.push('===========================');

        var full = lines.join('\n');
        console.log(full);

        // 同时输出到面板日志
        lines.forEach(function(l) { dlog(l, '#333'); });
        updateStatus('调试完成，看面板日志');
        return full;
    };

    /********************************* 初始化 ****************************************/
    function init() {
        dlog('YIT刷课助手 v2 启动', 'green');

        buildPanel();

        // 开始监听DOM
        observer.observe(document.body, { childList: true, subtree: true });

        // 初始扫描
        setTimeout(scanAllVideos, 2000);
        setTimeout(scanAllVideos, 5000);
        setTimeout(scanAllVideos, 10000);

        // 定期维护：倍速保持 + 暂停恢复 + 视频结束检测 + 跳过已完成
        setInterval(function() {
            // ★ 如果在跳过模式，持续尝试跳转到下一个未完成的
            if (skipMode) {
                if (isCurrentItemCompleted()) {
                    clickNext();
                } else {
                    skipMode = false;
                    scanAllVideos();
                }
                return;
            }

            var videos = findAllVideos();
            videos.forEach(function(v) {
                if (v.playbackRate !== CONFIG.videoRate && v.dataset.yitPlaying) {
                    v.playbackRate = CONFIG.videoRate;
                }
                // 兜底检测：视频播到末尾但 ended 事件未触发
                var d = v.duration;
                if (!isNaN(d) && d > 0 && !v.dataset.yitCompleted && v.dataset.yitPlaying) {
                    var remaining = d - v.currentTime;
                    if (remaining <= 2) {
                        dlog('兜底: 视频接近结尾(剩余'+remaining.toFixed(1)+'s)，直接触发完成', 'green');
                        v.currentTime = d;
                        if (v._yitComplete) v._yitComplete();
                    }
                }
                // 恢复暂停的 (但不恢复已完成的)
                if (v.dataset.yitPlaying && v.paused && !v.ended && !v.dataset.yitCompleted) {
                    v.play().catch(function(){});
                }
            });
        }, 3000);

        // 定期扫描新视频
        setInterval(function() {
            var videos = findAllVideos();
            videos.forEach(processVideo);
        }, 5000);

        dlog('初始化完成。在控制台运行 yitDebug() 查看调试信息', 'blue');
    }

    if (document.readyState === 'loading') {
        document.addEventListener('DOMContentLoaded', function(){ setTimeout(init, 1000); });
    } else {
        setTimeout(init, 1000);
    }

})();