// ==UserScript==
// @name         复制格式转换（Markdown）
// @namespace    http://tampermonkey.net/
// @version      2.1
// @description  选中内容后浮现按钮，点击自动复制为完整 Markdown 格式，确保排版与原文一致。支持数学公式、代码块语言标识、表格对齐。
// @author       KiwiFruit
// @match        *://*/*
// @grant        GM_setClipboard
// @license      MIT
// @downloadURL https://update.greasyfork.icu/scripts/532490/%E5%A4%8D%E5%88%B6%E6%A0%BC%E5%BC%8F%E8%BD%AC%E6%8D%A2%EF%BC%88Markdown%EF%BC%89.user.js
// @updateURL https://update.greasyfork.icu/scripts/532490/%E5%A4%8D%E5%88%B6%E6%A0%BC%E5%BC%8F%E8%BD%AC%E6%8D%A2%EF%BC%88Markdown%EF%BC%89.meta.js
// ==/UserScript==

(function () {
    'use strict';

    const config = {
        preserveEmptyLines: false, // 是否保留空行
        addSeparators: true, // 数学公式使用 $$ 分隔符
        mathSelector: '.math-formula', // 数学公式自定义选择器
    };

    // 创建浮动按钮
    const floatingButton = createFloatingButton();
    // 创建预览窗口
    const previewWindow = createPreviewWindow();

    function createFloatingButton() {
        const button = document.createElement('button');
        button.id = 'markdownCopyButton';
        button.innerText = '复制为 MD (Ctrl+Shift+C)';
        Object.assign(button.style, {
            position: 'fixed',
            top: '20px',
            right: '20px',
            padding: '10px 20px',
            backgroundColor: '#007bff',
            color: '#fff',
            border: 'none',
            borderRadius: '5px',
            cursor: 'pointer',
            zIndex: '9999',
            display: 'none',
            boxShadow: '0 4px 6px rgba(0,0,0,0.1)',
            transition: 'opacity 0.3s ease-in-out'
        });
        document.body.appendChild(button);
        return button;
    }

    function createPreviewWindow() {
        const preview = document.createElement('div');
        preview.id = 'markdownPreview';
        Object.assign(preview.style, {
            position: 'fixed',
            top: '60px',
            right: '20px',
            width: '300px',
            maxHeight: '400px',
            overflowY: 'auto',
            padding: '10px',
            backgroundColor: '#fff',
            border: '1px solid #ddd',
            boxShadow: '0 4px 6px rgba(0,0,0,0.1)',
            zIndex: '9999',
            display: 'none',
            fontFamily: 'monospace',
            fontSize: '14px',
            whiteSpace: 'pre-wrap',
            wordWrap: 'break-word'
        });
        document.body.appendChild(preview);
        return preview;
    }

    function showFloatingButton() {
        floatingButton.style.display = 'block';
    }

    function hideFloatingButton() {
        floatingButton.style.display = 'none';
        previewWindow.style.display = 'none';
    }

    function convertToMarkdown(node) {
    if (node.nodeType === Node.TEXT_NODE) {
        let text = node.textContent;
        return config.preserveEmptyLines ? text : text.trim() || '';
    }

    if (node.nodeType === Node.ELEMENT_NODE) {
        const tagName = node.tagName.toLowerCase();

        switch (tagName) {
            // 标题（h1-h6）：前后加空行
            case 'h1': case 'h2': case 'h3': case 'h4': case 'h5': case 'h6':
                return `\n\n${formatHeader(node)}\n\n`;

            // 换行符：<br> 转换为单个换行
            case 'br':
                return '\n';

            // 段落：<p> 前后加空行
            case 'p':
                return `\n\n${formatParagraph(node)}\n\n`;

            // 列表：<ul>/<ol> 前后加空行
            case 'ul': case 'ol':
                return `\n\n${formatList(node, tagName === 'ol')}\n\n`;

            // 引用：<blockquote> 前后加空行
            case 'blockquote':
                return `\n\n${formatBlockquote(node)}\n\n`;

            // 代码块：<pre> 前后加空行
            case 'pre':
                return `\n\n${formatCodeBlock(node)}\n\n`;

            // 内联代码：<code> 直接返回，不加空行
            case 'code':
                return formatInlineCode(node);

            // 链接：<a> 直接返回
            case 'a':
                return formatLink(node);

            // 图片：<img> 直接返回
            case 'img':
                return formatImage(node);

            // 加粗：<strong>/<b> 直接返回
            case 'strong': case 'b':
                return formatBold(node);

            // 斜体：<em>/<i> 直接返回
            case 'em': case 'i':
                return formatItalic(node);

            // 删除线：<del> 直接返回
            case 'del':
                return formatStrikethrough(node);

            // 水平线：<hr> 前后加空行
            case 'hr':
                return '\n\n---\n\n';

            // 表格：<table> 前后加空行
            case 'table':
                return `\n\n${formatTable(node)}\n\n`;

            // 数学公式：<span.math-formula> 前后加空行
            case 'span': case 'div':
                if (node.matches(config.mathSelector)) {
                    return `\n\n${formatMath(node)}\n\n`;
                }
                return processChildren(node);

            // 默认处理：递归子节点
            default:
                return processChildren(node);
        }
    }
    return '';
}

    function formatHeader(node) {
        const level = parseInt(node.tagName.slice(1));
        const content = processChildren(node).trim();
        return `${'#'.repeat(level)} ${content}`;
    }

    function formatParagraph(node) {
        const content = processChildren(node).trim();
        return `${content}`;
    }

    function formatList(node, isOrdered) {
        let markdown = '';
        let index = 1;
        for (const li of node.children) {
            const content = processChildren(li).trim();
            markdown += `${isOrdered ? `${index++}.` : '-' } ${content}\n`;
        }
        return `\n${markdown}\n`;
    }

    function formatBlockquote(node) {
        const content = processChildren(node).trim();
        return `> ${content.replace(/\n/g, '\n> ')}\n\n`;
    }

    function formatCodeBlock(node) {
        const langMatch = node.className.match(/language-(\w+)/);
        const lang = langMatch ? langMatch[1] : '';
        const code = node.textContent.trim();
        return `\`\`\`${lang}\n${code}\n\`\`\`\n\n`;
    }

    function formatInlineCode(node) {
        return `\`${node.textContent.trim()}\``;
    }

    function formatLink(node) {
        const text = processChildren(node).trim();
        const href = node.href || '';
        return `[${text}](${href})`;
    }

    function formatImage(node) {
        const alt = node.alt || 'Image';
        const src = node.src || '';
        return `![${alt}](${src})`;
    }

    function formatBold(node) {
        const content = processChildren(node).trim();
        return ` **${content}** `;
    }

    function formatItalic(node) {
        const content = processChildren(node).trim();
        return ` *${content}* `;
    }

    function formatStrikethrough(node) {
        const content = processChildren(node).trim();
        return `~~${content}~~`;
    }

    function formatTable(node) {
        const rows = Array.from(node.rows);
        if (rows.length === 0) return '';

        const headers = Array.from(rows[0].cells);
        const separator = headers.map(() => '---').join('|');
        const headerRow = `| ${headers.map(cell => cell.textContent.trim()).join(' | ')} |`;

        const dataRows = rows.slice(1).map(row => {
            const cells = Array.from(row.cells).map(cell => {
                return processChildren(cell).trim().replace(/\n/g, ' ');
            });
            return `| ${cells.join(' | ')} |`;
        }).join('\n');

        return `${headerRow}\n| ${separator} |\n${dataRows}\n\n`;
    }

    function formatMath(node) {
        const formula = node.textContent.trim();
        if (config.addSeparators) {
            return `$$\n${formula}\n$$\n\n`;
        } else {
            return `$${formula}$ `;
        }
    }

    function processChildren(node) {
        let result = '';
        for (const child of node.childNodes) {
            result += convertToMarkdown(child);
        }
        return result;
    }

    function extractAndConvertToMarkdown(range) {
        const fragment = range.cloneContents();
        const nodes = Array.from(fragment.childNodes);
        return nodes.map(node => convertToMarkdown(node)).join('').trim();
    }

    async function copyToClipboard(text) {
        try {
            if (typeof GM_setClipboard === 'function') {
                GM_setClipboard(text);
                return true;
            } else {
                await navigator.clipboard.writeText(text);
                console.log('Markdown 已复制到剪贴板');
                return true;
            }
        } catch (err) {
            console.error('复制失败:', err);
            return false;
        }
    }

    function showToast(message) {
        const toast = document.createElement('div');
        Object.assign(toast.style, {
            position: 'fixed',
            bottom: '20px',
            right: '20px',
            padding: '10px 20px',
            backgroundColor: '#333',
            color: '#fff',
            borderRadius: '5px',
            zIndex: '9999',
            boxShadow: '0 4px 6px rgba(0,0,0,0.1)',
            animation: 'fadeInOut 2s ease-in-out'
        });
        toast.innerText = message;
        document.body.appendChild(toast);
        setTimeout(() => toast.remove(), 2000);
    }

    document.addEventListener('mouseup', handleMouseUp);
    document.addEventListener('keydown', handleKeyDown);
    document.addEventListener('mousedown', handleMouseDown);

    function handleMouseUp(event) {
        const selection = window.getSelection();
        if (selection && !selection.isCollapsed) {
            showFloatingButton();
            floatingButton.onclick = async () => {
                try {
                    const range = selection.getRangeAt(0);
                    const markdownContent = extractAndConvertToMarkdown(range);
                    previewWindow.innerText = markdownContent;
                    previewWindow.style.display = 'block';
                    const success = await copyToClipboard(markdownContent);
                    if (success) {
                        showToast('内容已复制为 Markdown 格式！');
                    } else {
                        showToast('复制失败，请重试！');
                    }
                } catch (err) {
                    console.error('处理内容时出错:', err);
                    showToast(`发生错误：${err.message}`);
                } finally {
                    hideFloatingButton();
                }
            };
        } else {
            hideFloatingButton();
        }
    }

    function handleKeyDown(event) {
        if (event.ctrlKey && event.shiftKey && event.code === 'KeyC') {
            handleMouseUp(event);
        }
    }

    function handleMouseDown(event) {
        if (!floatingButton.contains(event.target) && !previewWindow.contains(event.target)) {
            hideFloatingButton();
        }
    }
})();