// ==UserScript==
// @name         中华医学远程继续教育课程视频自动播放与下一集跳转
// @namespace    http://tampermonkey.net/
// @version      1.0
// @description  打开课程视频后自动播放；若被浏览器阻止，点击页面任意处即开始；视频结束后自动跳转下一集
// @match        https://cme.yiigle.com/teaching/course?*
// @grant        none
// @run-at       document-end
// @license GPL-3.0
// ==/UserScript==

(function() {
    'use strict';

    let video = null;
    let checkInterval = null;

    function log(msg) {
        console.log('[AutoNext] ' + msg);
    }

    function getVideoElement() {
        return document.querySelector('video');
    }

    // 查找下一集的可点击元素（适配多种常见结构）
    function getNextVideoItem() {
        // 尝试多种可能的容器选择器
        const selectors = ['.item', '.chapter', '.lesson', '.video-item', 'li'];
        let items = [];
        for (const sel of selectors) {
            const found = document.querySelectorAll(sel);
            if (found.length > 0) {
                items = found;
                break;
            }
        }
        if (items.length === 0) {
            log('未找到课程列表项');
            return null;
        }

        for (let i = 0; i < items.length; i++) {
            const el = items[i];
            // 判断当前项是否激活（active 类或其子元素存在 active）
            const isActive = el.classList.contains('active') || el.querySelector('.active');
            if (isActive) {
                const next = items[i + 1];
                if (next) {
                    // 优先返回可点击的子元素（a 标签或含有 .title/.name 的元素）
                    const clickable = next.querySelector('a, .title, .name');
                    return clickable || next;
                } else {
                    log('已是最后一项');
                    return null;
                }
            }
        }
        log('未找到当前播放项');
        return null;
    }

    function goToNext() {
        const next = getNextVideoItem();
        if (next) {
            log('跳转下一集');
            next.click();
        } else {
            log('没有下一集');
        }
    }

    function bindEndedEvent(videoElem) {
        if (!videoElem) return;
        if (videoElem._autoNextBound) return;
        videoElem._autoNextBound = true;
        videoElem.addEventListener('ended', function() {
            log('视频播放结束');
            goToNext();
        });
        log('已绑定 ended 事件');
    }

    function playVideo(videoElem) {
        if (!videoElem) return Promise.reject('No video element');
        if (!videoElem.paused) return Promise.resolve();
        return videoElem.play();
    }

    // 显示一个浮动提示按钮（也可点击页面任意处触发）
    function showPlayHint() {
        if (document.getElementById('auto-play-hint')) return;
        const hint = document.createElement('div');
        hint.id = 'auto-play-hint';
        hint.style.cssText = `
            position: fixed;
            bottom: 80px;
            right: 20px;
            background: #409EFF;
            color: #fff;
            padding: 12px 20px;
            border-radius: 8px;
            font-size: 16px;
            cursor: pointer;
            z-index: 9999;
            box-shadow: 0 2px 12px rgba(0,0,0,0.3);
            font-family: sans-serif;
        `;
        hint.textContent = '▶ 点击开始自动播放';
        hint.addEventListener('click', function(e) {
            e.stopPropagation();
            const v = getVideoElement();
            if (v) {
                playVideo(v).then(() => {
                    log('用户点击按钮，播放成功');
                    hint.style.display = 'none';
                }).catch(err => log('播放失败：' + err));
            }
        });
        document.body.appendChild(hint);

        // 同时监听任意点击（可移除按钮后播放）
        const oneClick = function() {
            const v = getVideoElement();
            if (v && v.paused) {
                playVideo(v).then(() => {
                    log('用户点击任意处，播放成功');
                    if (hint.parentNode) hint.style.display = 'none';
                }).catch(err => {});
            }
            document.removeEventListener('click', oneClick);
            document.removeEventListener('touchstart', oneClick);
        };
        document.addEventListener('click', oneClick);
        document.addEventListener('touchstart', oneClick);
        log('已显示播放提示，等待用户交互');
    }

    function initAutoPlay() {
        const v = getVideoElement();
        if (!v) {
            log('视频元素未找到，继续等待...');
            return false;
        }
        video = v;
        bindEndedEvent(v);

        if (!v.paused) {
            log('视频已在播放');
            return true;
        }

        playVideo(v).then(() => {
            log('自动播放成功');
        }).catch(err => {
            if (err.name === 'NotAllowedError') {
                log('自动播放被浏览器阻止，等待用户交互');
                showPlayHint();
            } else {
                log('播放异常：' + err.message);
            }
        });
        return true;
    }

    // 循环检测视频元素
    function start() {
        if (checkInterval) return;
        let attempts = 0;
        checkInterval = setInterval(function() {
            attempts++;
            const v = getVideoElement();
            if (v) {
                clearInterval(checkInterval);
                checkInterval = null;
                initAutoPlay();
            } else if (attempts > 30) {
                clearInterval(checkInterval);
                checkInterval = null;
                log('超时未找到视频元素');
            }
        }, 1000);
    }

    // 页面加载后启动
    if (document.readyState === 'complete') {
        setTimeout(start, 1000);
    } else {
        window.addEventListener('load', start);
    }

})();