【油猴脚本】Base64解码 -选中一键解码，彻底告别切屏复制粘贴

// ==UserScript==

// @name         Linux.do Base64解码 

// @namespace    https://linux.do/

// @version      3.0

// @description  选中Base64文本后，在弹出菜单点击解码，原文下方插入可复制的代码块

// @author       hum&&deepseek

// @match        https://linux.do/t/topic/*

// @grant        none

// ==/UserScript==



(function () {

  'use strict';



  // 解码 Base64，支持 UTF-8 多字节字符

  function decodeBase64ToUnicode(str) {

    try {

      const binary = atob(str.trim());

      const bytes = new Uint8Array(binary.length);

      for (let i = 0; i < binary.length; i++) {

        bytes[i] = binary.charCodeAt(i);

      }

      return new TextDecoder('utf-8').decode(bytes);

    } catch {

      return null;

    }

  }



  // 在选区末尾插入带复制和关闭按钮的代码块

  function insertDecodedBlock(decodedText, range) {

    // 外层容器，模拟论坛代码块样式

    const wrapper = document.createElement('div');

    wrapper.className = 'md-codeblock';

    Object.assign(wrapper.style, {

      position: 'relative',

      marginTop: '8px',

      marginBottom: '8px'

    });



    const pre = document.createElement('pre');

    const code = document.createElement('code');

    code.textContent = decodedText;

    pre.appendChild(code);

    wrapper.appendChild(pre);



    // 按钮工具栏

    const toolbar = document.createElement('div');

    toolbar.className = 'codeblock-button-wrapper';

    Object.assign(toolbar.style, {

      position: 'absolute',

      top: '4px',

      right: '4px',

      display: 'flex',

      gap: '4px'

    });



    // --- 复制按钮（完全自己控制）---

    const copyBtn = document.createElement('button');

    copyBtn.className = 'btn nohighlight btn-flat';

    copyBtn.setAttribute('aria-label', '复制解码文本');

    copyBtn.innerHTML = '<svg class="fa d-icon d-icon-copy svg-icon fa-width-auto svg-string" width="1em" height="1em" aria-hidden="true" xmlns="http://www.w3.org/2000/svg"><use href="#copy"></use></svg>';



    // 点击复制，并显示“已复制！”

    copyBtn.addEventListener('click', (e) => {

      e.stopPropagation();

      navigator.clipboard.writeText(decodedText).then(() => {

        copyBtn.innerHTML = '已复制！';

        copyBtn.style.pointerEvents = 'none';

        setTimeout(() => {

          copyBtn.innerHTML = '<svg class="fa d-icon d-icon-copy svg-icon fa-width-auto svg-string" width="1em" height="1em" aria-hidden="true" xmlns="http://www.w3.org/2000/svg"><use href="#copy"></use></svg>';

          copyBtn.style.pointerEvents = '';

        }, 2000);

      }).catch(() => alert('复制失败，请手动复制'));

    });



    // --- 关闭按钮 ---

    const closeBtn = document.createElement('button');

    closeBtn.className = 'btn nohighlight btn-flat';

    closeBtn.innerHTML = '✖';

    closeBtn.title = '关闭';

    closeBtn.addEventListener('click', () => wrapper.remove());



    toolbar.appendChild(copyBtn);

    toolbar.appendChild(closeBtn);

    wrapper.appendChild(toolbar);



    // 插入到选区末尾

    range.collapse(false);

    range.insertNode(wrapper);

    range.setStartAfter(wrapper);

    range.collapse(true);

    const sel = window.getSelection();

    sel.removeAllRanges();

    sel.addRange(range);

  }



  // 在浮动菜单中添加解码按钮

  function addDecodeButton(menu) {

    if (menu.dataset.base64DecodeAdded) return;

    menu.dataset.base64DecodeAdded = 'true';



    // 优先查找 .quote-button 内的 .buttons，兼容多种结构

    const btns = menu.querySelector('.quote-button .buttons') || menu.querySelector('.buttons');

    if (!btns) return;



    const decodeBtn = document.createElement('button');

    decodeBtn.className = 'btn btn-icon-text btn-flat';

    decodeBtn.title = 'Base64 解码';

    decodeBtn.type = 'button';

    decodeBtn.innerHTML = '<span class="fa d-icon">🔓</span><span class="d-button-label">Base64解码</span>';



    decodeBtn.addEventListener('click', (e) => {

      e.preventDefault();

      e.stopPropagation();



      const selection = window.getSelection();

      if (!selection.rangeCount || !selection.toString().trim()) {

        alert('请先选中一段 Base64 文本');

        return;

      }



      const raw = selection.toString().trim();

      const decoded = decodeBase64ToUnicode(raw);

      if (decoded === null) {

        alert('解码失败，请确认内容是有效的 Base64 编码');

        return;

      }



      insertDecodedBlock(decoded, selection.getRangeAt(0));



      // 点击一下 body 关闭浮动菜单

      document.body.click();

    });



    btns.appendChild(decodeBtn);

  }



  // 监听 #d-menu-portals 内菜单的创建

  function startObserver() {

    const portal = document.getElementById('d-menu-portals');

    if (!portal) {

      setTimeout(startObserver, 500);

      return;

    }



    // 处理已存在的菜单

    portal.querySelectorAll('div.fk-d-menu').forEach(addDecodeButton);



    const observer = new MutationObserver(mutations => {

      for (const mut of mutations) {

        for (const node of mut.addedNodes) {

          if (node.nodeType === Node.ELEMENT_NODE) {

            if (node.matches && node.matches('div.fk-d-menu')) {

              addDecodeButton(node);

            }

            if (node.querySelectorAll) {

              node.querySelectorAll('div.fk-d-menu').forEach(addDecodeButton);

            }

          }

        }

      }

    });



    observer.observe(portal, { childList: true, subtree: true });

  }



  if (document.readyState === 'loading') {

    window.addEventListener('DOMContentLoaded', startObserver);

  } else {

    startObserver();

  }

})();