// ==UserScript==
// @name         自动添加空格，在 CJK （中日繁）字符和英文字母之间自动添加空格
// @namespace    pangu-userscript
// @version      1.2.1
// @license      MIT
// @description  在 CJK （中日繁）字符和英文字母之间自动添加空格，考虑了代码块、DOM 动态更新等情况。
// @match        http*://*/*
// @grant        none
// @require      https://unpkg.com/pangu@4.0.7/dist/browser/pangu.min.js
// @downloadURL none
// ==/UserScript==

;(function () {
  'use strict';

  function addSpacing() {
    const elements = document.querySelectorAll(
      'body *:not(script):not(style):not(noscript):not(pre):not(code):not(input):not([contenteditable="true"])'
    );
    elements.forEach(element => {
      if (element.childNodes.length === 1 && element.childNodes[0].nodeType === Node.TEXT_NODE) {
        const originalText = element.textContent;
        const newText = pangu.spacing(originalText);
        if (originalText !== newText) {
          element.textContent = newText;
        }
      }
    });
  }

  function observeDOM(observer) {
    observer.observe(document.body, { childList: true, subtree: true });
  }

  function debounce(func, wait, immediate) {
    let timeout;
    return function () {
      const context = this;
      const args = arguments;
      const later = function () {
        timeout = null;
        if (!immediate) func.apply(context, args);
      };
      const callNow = immediate && !timeout;
      clearTimeout(timeout);
      timeout = setTimeout(later, wait);
      if (callNow) func.apply(context, args);
    };
  }

  const addSpacingDebounced = debounce(addSpacing, 300);

  // Run once when the script is loaded
  addSpacing();

  // Run every time the content of the page is changed
  const observer = new MutationObserver(() => {
    requestAnimationFrame(() => {
      addSpacingDebounced();
    });
  });

  // Start observing when the DOM is ready
  if (document.readyState === 'loading') {
    document.addEventListener('DOMContentLoaded', () => {
      observeDOM(observer);
    });
  } else {
    observeDOM(observer);
  }
})();