// ==UserScript==
// @name         超星/网课专用 PDF 提取器 (更新含移除遮挡功能)
// @namespace    http://tampermonkey.net/
// @version      3.1
// @description  自动录屏/截图并将网课课件/题目转换为 PDF，支持一键移除遮挡弹窗
// @author       YourName
// @match        *://*.chaoxing.com/*
// @match        *://*.zhihuishu.com/*
// @match        *://*.icve.com.cn/*
// @match        *://*.edu.cn/*
// @include      *
// @run-at       document-end
// @grant        GM_registerMenuCommand
// @grant        GM_addStyle
// @require      https://cdnjs.cloudflare.com/ajax/libs/html2canvas/1.4.1/html2canvas.min.js
// @require      https://cdnjs.cloudflare.com/ajax/libs/jspdf/2.5.1/jspdf.umd.min.js
// ==/UserScript==
 
(function() {
    'use strict';
 
    // ==========================================
    // 1. UI 部分：创建悬浮按钮组
    // ==========================================
    function createFloatingButtons() {
        const container = document.createElement('div');
        container.id = 'pdf-extractor-container';
        container.style.cssText = `
            position: fixed;
            bottom: 20px;
            right: 20px;
            z-index: 999999;
            display: flex;
            flex-direction: column;
            gap: 10px;
        `;
 
        // --- 按钮 1: PDF 提取 (绿色) ---
        const extractBtn = document.createElement('button');
        extractBtn.id = 'pdf-extractor-btn';
        extractBtn.innerText = 'PDF提取';
        styleButton(extractBtn, '#4CAF50'); // Green
        extractBtn.onclick = (e) => {
            e.stopPropagation();
            enableSelectionMode();
        };
 
        // --- 按钮 2: 移除遮挡 (红色) ---
        const removeBtn = document.createElement('button');
        removeBtn.id = 'element-remover-btn';
        removeBtn.innerText = '✕ 移除遮挡';
        styleButton(removeBtn, '#f44336'); // Red
        removeBtn.onclick = (e) => {
            e.stopPropagation();
            enableRemoverMode();
        };
 
        container.appendChild(removeBtn);
        container.appendChild(extractBtn);
        document.body.appendChild(container);
    }
 
    function styleButton(btn, color) {
        btn.style.cssText = `
            background-color: ${color};
            color: white;
            padding: 10px 15px;
            border: none;
            border-radius: 50px;
            cursor: pointer;
            box-shadow: 0 4px 6px rgba(0,0,0,0.2);
            font-family: Arial, sans-serif;
            font-size: 14px;
            transition: transform 0.2s, background-color 0.2s;
            white-space: nowrap;
        `;
        btn.onmouseover = () => btn.style.transform = 'scale(1.05)';
        btn.onmouseout = () => btn.style.transform = 'scale(1)';
    }
 
    // 初始化 UI
    createFloatingButtons();
 
 
    // ==========================================
    // 2. 核心功能 A：移除遮挡 (新增功能)
    // ==========================================
    let isRemoverMode = false;
    let lastRemoverHighlight = null;
 
    function enableRemoverMode() {
        if (isRemoverMode) return;
        isRemoverMode = true;
 
        const btn = document.getElementById('element-remover-btn');
        if(btn) {
            btn.innerText = '请点击要删除的元素...';
            btn.style.backgroundColor = '#FF9800'; // Orange warning
        }
 
        document.addEventListener('mouseover', highlightRemoverElement, true);
        document.addEventListener('click', executeRemoveElement, true);
        
        showToast("【移除模式】\n点击那个挡住你的弹窗或背景\n(点击后立即删除)");
    }
 
    function highlightRemoverElement(e) {
        // 忽略我们的控制按钮
        if (document.getElementById('pdf-extractor-container').contains(e.target)) return;
 
        if (lastRemoverHighlight) lastRemoverHighlight.style.outline = '';
        e.target.style.outline = '4px dashed red'; // 虚线红色表示删除
        e.target.style.cursor = 'crosshair';
        lastRemoverHighlight = e.target;
    }
 
    function executeRemoveElement(e) {
        // 忽略点击按钮本身
        if (document.getElementById('pdf-extractor-container').contains(e.target)) return;
 
        e.preventDefault();
        e.stopPropagation();
 
        const target = e.target;
        
        // 停止监听
        document.removeEventListener('mouseover', highlightRemoverElement, true);
        document.removeEventListener('click', executeRemoveElement, true);
        
        if (lastRemoverHighlight) lastRemoverHighlight.style.outline = '';
        
        // 删除元素
        if(target) {
            target.remove();
            showToast("已删除遮挡元素！");
        }
 
        // 恢复按钮状态
        isRemoverMode = false;
        const btn = document.getElementById('element-remover-btn');
        if(btn) {
            btn.innerText = '✕ 移除遮挡';
            btn.style.backgroundColor = '#f44336';
        }
    }
 
 
    // ==========================================
    // 3. 核心功能 B：PDF 提取逻辑 (原逻辑)
    // ==========================================
    let isSelectionMode = false;
    let lastHighlighted = null;
 
    function enableSelectionMode() {
        if (isSelectionMode) return;
        isSelectionMode = true;
        
        const btn = document.getElementById('pdf-extractor-btn');
        if(btn) btn.innerText = '请点击课件区域';
        if(btn) btn.style.backgroundColor = '#2196F3'; // Blue
 
        document.addEventListener('mouseover', highlightElement, true);
        document.addEventListener('click', startCaptureProcess, true);
        
        showToast("【提取模式】\n请点击你的 PPT/课件滚动区域！");
    }
 
    function highlightElement(e) {
        if (document.getElementById('pdf-extractor-container').contains(e.target)) return;
 
        if (lastHighlighted) lastHighlighted.style.outline = '';
        e.target.style.outline = '4px solid #4CAF50'; // 实线绿色表示提取
        lastHighlighted = e.target;
    }
 
    function showToast(msg) {
        const toast = document.createElement('div');
        toast.innerText = msg;
        toast.style.cssText = `
            position: fixed;
            top: 20px;
            left: 50%;
            transform: translateX(-50%);
            background: rgba(0,0,0,0.85);
            color: #fff;
            padding: 12px 24px;
            border-radius: 8px;
            z-index: 1000000;
            text-align: center;
            font-size: 14px;
            box-shadow: 0 4px 12px rgba(0,0,0,0.3);
            pointer-events: none;
        `;
        document.body.appendChild(toast);
        setTimeout(() => toast.remove(), 3500);
    }
 
    // --- 滚动与截图逻辑 ---
    
    function findScrollParent(element) {
        let el = element;
        while (el && el !== document.body && el !== document.documentElement) {
            const style = window.getComputedStyle(el);
            const overflowY = style.overflowY;
            if ((overflowY === 'auto' || overflowY === 'scroll') && el.scrollHeight > el.clientHeight) {
                return el;
            }
            el = el.parentElement;
        }
        return document.documentElement; 
    }
 
    async function captureVisibleArea() {
        const container = document.getElementById('pdf-extractor-container');
        if(container) container.style.display = 'none'; // 截图时隐藏所有按钮
 
        try {
            const canvas = await html2canvas(document.body, {
                useCORS: true,
                allowTaint: true,
                scrollX: window.scrollX,
                scrollY: window.scrollY,
                windowWidth: window.innerWidth,
                windowHeight: window.innerHeight,
                x: window.scrollX,
                y: window.scrollY,
                width: window.innerWidth,
                height: window.innerHeight,
                ignoreElements: (element) => element.id === 'pdf-extractor-container'
            });
            
            if(container) container.style.display = 'flex';
            return canvas.toDataURL('image/jpeg', 0.9);
        } catch (e) {
            console.error("截图失败", e);
            if(container) container.style.display = 'flex';
            return null;
        }
    }
 
    function getImageDimensions(src) {
        return new Promise((resolve) => {
            const img = new Image();
            img.onload = () => {
                resolve({ width: img.width, height: img.height });
            };
            img.src = src;
        });
    }
 
    async function startCaptureProcess(e) {
        e.preventDefault();
        e.stopPropagation();
 
        document.removeEventListener('mouseover', highlightElement, true);
        document.removeEventListener('click', startCaptureProcess, true);
        if (lastHighlighted) lastHighlighted.style.outline = '';
        
        isSelectionMode = false;
        const btn = document.getElementById('pdf-extractor-btn');
 
        const scrollContainer = findScrollParent(e.target);
        if (!scrollContainer) {
            alert("未找到可滚动的区域，请重试");
            if(btn) { btn.innerText = 'PDF提取'; btn.style.backgroundColor = '#4CAF50'; }
            return;
        }
 
        if(btn) {
            btn.innerText = '处理中...';
            btn.style.backgroundColor = '#999';
            btn.disabled = true;
        }
        
        await runScreenCapture(scrollContainer);
        
        if(btn) { 
            btn.innerText = 'PDF提取'; 
            btn.style.backgroundColor = '#4CAF50'; 
            btn.disabled = false;
        }
    }
 
    async function runScreenCapture(container) {
        alert("开始处理！\n请确保已‘移除遮挡’，否则会被录入。\n请不要移动鼠标。");
 
        const isWindowScroll = (container === document.documentElement || container === document.body);
        const totalHeight = container.scrollHeight;
        const viewHeight = isWindowScroll ? window.innerHeight : container.clientHeight;
        
        let currentScroll = 0;
        let pageIndex = 0;
        let pdf = null; 
 
        const originalOverflow = container.style.overflow;
        if(!isWindowScroll) container.style.overflow = 'hidden'; 
        else document.documentElement.style.overflow = 'hidden';
 
        try {
            const { jsPDF } = window.jspdf;
 
            while (currentScroll < totalHeight) {
                if (isWindowScroll) window.scrollTo(0, currentScroll);
                else container.scrollTop = currentScroll;
                
                await new Promise(r => setTimeout(r, 1500)); 
 
                console.log(`正在截取第 ${pageIndex + 1} 页...`);
                const imgData = await captureVisibleArea();
                
                if (!imgData) {
                    currentScroll += viewHeight;
                    continue;
                }
 
                const imgProps = await getImageDimensions(imgData);
                const imgWidth = imgProps.width;
                const imgHeight = imgProps.height;
                const orientation = imgWidth > imgHeight ? 'l' : 'p';
 
                if (pageIndex === 0) {
                    pdf = new jsPDF({
                        orientation: orientation,
                        unit: 'px',
                        format: [imgWidth, imgHeight]
                    });
                } else {
                    pdf.addPage([imgWidth, imgHeight], orientation);
                }
 
                pdf.addImage(imgData, 'JPEG', 0, 0, imgWidth, imgHeight);
 
                currentScroll += viewHeight;
                pageIndex++;
            }
 
            if(!isWindowScroll) container.style.overflow = originalOverflow;
            else document.documentElement.style.overflow = originalOverflow;
 
            if (pdf) {
                pdf.save(`课件提取_${Date.now()}.pdf`);
                alert("下载完成！");
            } else {
                alert("错误：未获取到内容");
            }
 
        } catch (err) {
            console.error(err);
            alert("出错: " + err.message);
            if(!isWindowScroll) container.style.overflow = originalOverflow;
            else document.documentElement.style.overflow = originalOverflow;
        }
    }
 
})();