// ==UserScript==
// @name         学习通视频加速器-强制开倍数，快速通过视频
// @namespace    qinghy-10
// @version      1.2
// @description  为“学习通”视频播放器新增多档倍速播放功能，支持 0.5x、1x、1.25x、1.5x、2.0x、4.0x 等多种播放速度，让用户灵活掌控学习节奏，高效完成课程内容。该功能采用先进的音频时间拉伸技术，在加速或减速播放时仍能保持音调自然清晰，显著提升网课学习效率与观看体验。（支持视频：超星学习通 | 智慧树 | MOOC | 继续教育类 | 优课学堂 |  青书学堂 | 优学院 | 中国大学mooc | 智慧职教 | 青书学堂 ）学习通交流群：74028813 欢迎大家一起学习
// @author       学习助手
// @license      MIT
// @icon         https://pan-yz.chaoxing.com/favicon.ico
// @match        https://*.chaoxing.com/*
// @match        https://*passport.zhihuishu.com/*
// @match        https://*iam.pt.ouchn.cn/*
// @match        https://chaoxing.com/*
// @match        https://mooc*.chaoxing.com/*
// @match        https://*.www.icourse163.org/
// @match        https://i.mooc.chaoxing.com/*
// @match        https://dushu.chaoxing.com/*

// @grant        none
// @run-at       document-idle
// ==/UserScript==

(function () {
    'use strict';

    // 防止重复注入
    if (document.getElementById('speedControlPanel')) return;

    // 检查当前页面是否有 video 元素（适用于顶层或 iframe）
    function hasVideo() {
        return document.querySelector('video') !== null;
    }

    function addSpeedControlPanel() {
        const panel = document.createElement('div');
        panel.id = 'speedControlPanel';
        panel.innerHTML = `
            <div style="
                position: fixed;
                top: 20px;
                right: 20px;
                background: rgba(0,0,0,0.85);
                color: white;
                padding: 10px;
                border-radius: 6px;
                z-index: 2147483647;
                font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
                font-size: 13px;
                box-shadow: 0 2px 8px rgba(0,0,0,0.3);
            ">
                <div style="margin-bottom: 6px; font-weight: bold;">▶ 播放速度</div>
                <div>
                    <button class="speed-btn" data-speed="0.5">0.5x</button>
                    <button class="speed-btn" data-speed="1.0">1.0x</button>
                    <button class="speed-btn" data-speed="1.25">1.25x</button>
                    <button class="speed-btn" data-speed="1.5">1.5x</button>
                    <button class="speed-btn" data-speed="2.0">2.0x</button>
                    <button class="speed-btn" data-speed="4.0">4.0x</button>
                </div>
                <div style="margin-top: 6px; font-size: 12px; opacity: 0.9;">
                    当前: <span id="currentSpeed">1.0x</span>
                </div>
            </div>
        `;
        document.body.appendChild(panel);

        const style = document.createElement('style');
        style.textContent = `
            .speed-btn {
                background: #1e88e5;
                border: none;
                color: white;
                padding: 4px 8px;
                margin: 2px;
                cursor: pointer;
                border-radius: 4px;
                font-size: 12px;
                transition: background 0.2s;
            }
            .speed-btn:hover {
                background: #1976d2;
            }
            .speed-btn:active {
                transform: scale(0.95);
            }
        `;
        document.head.appendChild(style);

        const buttons = panel.querySelectorAll('.speed-btn');
        buttons.forEach(btn => {
            btn.addEventListener('click', function () {
                const speed = parseFloat(this.dataset.speed);
                setPlaybackRate(speed);
            });
        });

        // 初始化显示
        const video = document.querySelector('video');
        if (video) {
            updateCurrentSpeed(video.playbackRate);
        }
    }

    function setPlaybackRate(rate) {
        const videos = document.querySelectorAll('video');
        videos.forEach(v => {
            try {
                v.playbackRate = rate;
                updateCurrentSpeed(rate);
            } catch (e) {
                console.warn('无法设置播放速度:', e);
            }
        });
    }

    function updateCurrentSpeed(rate) {
        const el = document.getElementById('currentSpeed');
        if (el) {
            el.textContent = rate + 'x';
        }
    }

    // 尝试初始化
    function tryInit() {
        if (hasVideo() && !document.getElementById('speedControlPanel')) {
            // 确保 body 已存在
            if (document.body) {
                addSpeedControlPanel();
            }
        }
    }

    // 立即尝试
    if (document.readyState === 'loading') {
        window.addEventListener('DOMContentLoaded', tryInit);
    } else {
        tryInit();
    }

    // 轮询 + MutationObserver 双保险
    const observer = new MutationObserver(() => {
        if (hasVideo() && !document.getElementById('speedControlPanel')) {
            tryInit();
        }
    });
    observer.observe(document.documentElement || document.body, {
        childList: true,
        subtree: true
    });

    // 每3秒兜底检查
    setInterval(tryInit, 3000);
})();