// ==UserScript==
// @name         Email Copy Button for All Sites
// @name:zh-CN   全站邮箱一键复制
// @namespace    http://tampermonkey.net/
// @version      2.5
// @description  Automatically detects email addresses on any webpage and adds a one-click copy button. Supports plain text emails, mailto links, input field values, aria attributes. Deduplication via DOM attribute markers (not WeakSet) to survive text-node replacement and SPA re-renders.
// @description:zh-CN 在任意网页自动识别邮箱地址并添加一键复制按钮。通过 DOM 属性标记去重（而非 WeakSet），修复文本节点替换后新节点被重复扫描导致无限按钮的问题。
// @author       Nosy Swab
// @match        *://*/*
// @run-at       document-end
// @grant        none
// @license      MIT
// ==/UserScript==

(function () {
  'use strict';

  var EMAIL_RE  = /[a-zA-Z0-9._%+\-]+@[a-zA-Z0-9.\-]+\.[a-zA-Z]{2,}/;
  var EMAIL_RE_G = /[a-zA-Z0-9._%+\-]+@[a-zA-Z0-9.\-]+\.[a-zA-Z]{2,}/g;

  // Marks buttons we inject
  var BTN_ATTR = 'data-ecb-btn';
  // Marks source elements already processed
  var DONE_ATTR = 'data-ecb-done';
  // Scanning re-entrancy guard
  var _scanning = false;

  var SKIP_TAGS = new Set([
    'SCRIPT','STYLE','NOSCRIPT','CODE','PRE','SVG','CANVAS',
    'HEAD','TEMPLATE','TEXTAREA'
  ]);

  function cleanEmail(raw) {
    return raw.replace(/[();:'">[\]]+$/, '').trim();
  }

  // -- Copy helper: execCommand first, modern API as fallback ------------
  function copyToClipboard(text) {
    var copied = false;
    try {
      var ta = document.createElement('textarea');
      ta.value = text;
      ta.style.cssText = 'position:fixed;opacity:0;top:0;left:0;width:1px;height:1px';
      document.body.appendChild(ta);
      ta.focus();
      ta.select();
      copied = document.execCommand('copy');
      document.body.removeChild(ta);
    } catch (err) {
      copied = false;
    }
    if (!copied) {
      try {
        navigator.clipboard.writeText(text).catch(function () {});
        copied = true;
      } catch (err) {}
    }
    return copied;
  }

  // -- Button factory ---------------------------------------------------
  function makeBtn(email) {
    var btn = document.createElement('button');
    btn.textContent = '\uD83D\uDCCB';
    btn.setAttribute(BTN_ATTR, '1');
    btn.style.cssText = [
      'display:inline-flex','align-items:center','justify-content:center',
      'margin-left:4px','padding:1px 5px','font-size:12px','line-height:1',
      'border:1px solid #d9d9d9','border-radius:4px','background:#fff',
      'cursor:pointer','vertical-align:middle','transition:background 0.15s',
      'flex-shrink:0'
    ].join(';');
    btn.addEventListener('mouseenter', function () { btn.style.background = '#f0f0f0'; });
    btn.addEventListener('mouseleave', function () { btn.style.background = '#fff'; });
    btn.addEventListener('click', function (e) {
      e.preventDefault();
      e.stopPropagation();
      copyToClipboard(email);
      var orig = btn.textContent;
      btn.textContent = '\u2713';
      btn.style.background = '#52c41a';
      btn.style.color = '#fff';
      btn.style.borderColor = '#52c41a';
      setTimeout(function () {
        btn.textContent = orig;
        btn.style.background = '#fff';
        btn.style.color = '';
        btn.style.borderColor = '#d9d9d9';
      }, 1500);
    });
    return btn;
  }

  // -- Text nodes -------------------------------------------------------
  function injectIntoTextNode(node) {
    var text = node.nodeValue;
    if (!text || !EMAIL_RE.test(text)) return;
    var parent = node.parentNode;
    if (!parent || !parent.tagName) return;
    if (SKIP_TAGS.has(parent.tagName)) return;
    if (parent.getAttribute(BTN_ATTR)) return;
    if (parent.getAttribute(DONE_ATTR)) return;

    var matches = text.match(EMAIL_RE_G);
    if (!matches) return;

    parent.setAttribute(DONE_ATTR, '1');

    var parts = text.split(EMAIL_RE_G);
    var frag  = document.createDocumentFragment();
    parts.forEach(function (part, i) {
      frag.appendChild(document.createTextNode(part));
      if (i < matches.length) {
        var email = cleanEmail(matches[i]);
        if (email) frag.appendChild(makeBtn(email));
      }
    });
    parent.replaceChild(frag, node);
  }

  // -- mailto links -----------------------------------------------------
  // FIX v2.5: If the <a> already contains a native button/icon (like HK01),
  // skip injection to avoid duplicate buttons. We still mark DONE_ATTR on
  // the <a> so child elements are not scanned again.
  function injectIntoMailto(a) {
    if (a.getAttribute(DONE_ATTR)) return;
    var href  = a.getAttribute('href') || '';
    var match = href.match(/^mailto:([^?]+)/);
    if (!match) return;
    var email = cleanEmail(match[1]);
    if (!email) return;

    // Always mark the <a> as done first, so walkNode won't scan its children
    a.setAttribute(DONE_ATTR, '1');

    // If the <a> already has a child button/interactive element, the site
    // has its own copy UI -- just attach our click handler to the existing
    // button instead of inserting a new one next to the link.
    var existingBtn = a.querySelector('button, [role="button"]');
    if (existingBtn && !existingBtn.getAttribute(BTN_ATTR)) {
      // Wrap existing button: hijack clicks to also copy to clipboard
      existingBtn.addEventListener('click', function (e) {
        e.stopPropagation();
        copyToClipboard(email);
      });
      return;
    }

    // No native button -- insert our own after the <a>
    a.insertAdjacentElement('afterend', makeBtn(email));
  }

  // -- Input / textarea fields ------------------------------------------
  function injectIntoInput(el) {
    if (el.getAttribute(DONE_ATTR)) return;
    if (el.type === 'hidden') return;
    var val = el.value || '';
    var m   = val.match(EMAIL_RE);
    if (!m) return;
    var email = cleanEmail(m[0]);
    if (!email) return;
    el.setAttribute(DONE_ATTR, '1');
    el.insertAdjacentElement('afterend', makeBtn(email));
  }

  // -- Aria attributes --------------------------------------------------
  function injectIntoAria(el) {
    if (el.getAttribute(DONE_ATTR)) return;
    // Skip elements that are inside a mailto <a> already handled
    if (el.closest && el.closest('a[' + DONE_ATTR + ']')) return;
    var label = el.getAttribute('aria-label') || el.getAttribute('aria-description') || '';
    var m = label.match(EMAIL_RE);
    if (!m) return;
    var email = cleanEmail(m[0]);
    if (!email) return;
    el.setAttribute(DONE_ATTR, '1');
    el.insertAdjacentElement('afterend', makeBtn(email));
  }

  // -- Walk the DOM -----------------------------------------------------
  function walkNode(root) {
    var walker = document.createTreeWalker(
      root,
      NodeFilter.SHOW_TEXT | NodeFilter.SHOW_ELEMENT,
      {
        acceptNode: function (node) {
          if (node.nodeType === Node.ELEMENT_NODE) {
            if (SKIP_TAGS.has(node.tagName)) return NodeFilter.FILTER_REJECT;
            if (node.getAttribute(BTN_ATTR)) return NodeFilter.FILTER_REJECT;
            // FIX v2.5: skip children of already-processed mailto links
            if (node.tagName === 'A' && node.getAttribute('href') &&
                node.getAttribute('href').indexOf('mailto:') === 0 &&
                node.getAttribute(DONE_ATTR)) return NodeFilter.FILTER_REJECT;
          }
          return NodeFilter.FILTER_ACCEPT;
        }
      },
      false
    );

    var textNodes = [];
    var node;
    while ((node = walker.nextNode())) {
      if (node.nodeType === Node.TEXT_NODE) {
        textNodes.push(node);
      } else if (node.nodeType === Node.ELEMENT_NODE) {
        var tag = node.tagName;
        if (tag === 'A')        injectIntoMailto(node);
        if (tag === 'INPUT' || tag === 'TEXTAREA') injectIntoInput(node);
        injectIntoAria(node);
      }
    }
    textNodes.forEach(injectIntoTextNode);
  }

  // -- Initial scan -----------------------------------------------------
  walkNode(document.body);

  // -- MutationObserver for SPA/dynamic pages ---------------------------
  var observer = new MutationObserver(function (mutations) {
    if (_scanning) return;
    _scanning = true;
    try {
      var addedRoots = new Set();
      mutations.forEach(function (m) {
        m.addedNodes.forEach(function (n) {
          if (n.nodeType === Node.ELEMENT_NODE || n.nodeType === Node.TEXT_NODE) {
            var root = n.nodeType === Node.ELEMENT_NODE ? n : n.parentElement;
            if (root && !root.getAttribute(BTN_ATTR)) addedRoots.add(root);
          }
        });
      });
      addedRoots.forEach(function (root) {
        if (document.body && document.body.contains(root)) walkNode(root);
      });
    } finally {
      _scanning = false;
    }
  });

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

})();