// email-svg.js
(function () {
  // ============== 可配置项 ==============
  const FONT_URL = "/_upload/tpl/04/62/1122/template1122/extends/roboto.woff"; // 使用 .ttf/.otf/.woff（不要 woff2）
  const FALLBACK_FONT_URL = "https://unpkg.com/@fontsource/roboto/files/roboto-latin-400-normal.ttf";
  const DEFAULT_DOMAIN = "ntu.edu.cn";        // [de] 前面没写域名时使用
  const ROOT_SELECTOR = "p, span, li, div";   // 扫描这些容器里的文本节点
  const DPR_BONUS = (window.devicePixelRatio || 1) >= 2 ? 1.32 : 1.25; // HiDPI 轻微放大
  const AUTO_LOAD_OPENTYPE = false; // 若页面未引入 opentype.js，可设为 true 自动从 CDN 加载

  // 允许省略域名： (domain)? [de] user
  const PATTERN = /(?:([A-Za-z0-9.-]+\.[A-Za-z]{2,}))?\s*\[\s*de\s*\]\s*([A-Za-z0-9._%+-]+)/g;

  // ====== 全页面   清理（U+00A0 与字面量  ）======
  // 跳过不应处理的区域
  function shouldSkip(textNode) {
    let p = textNode && textNode.parentNode;
    while (p && p.nodeType === 1) {
      const tn = p.tagName;
      if (tn === "SCRIPT" || tn === "STYLE" || tn === "NOSCRIPT" || tn === "TEXTAREA") return true;
      p = p.parentNode;
    }
    return false;
  }
  // 清理单个文本节点
  function cleanNbspNode(node) {
    let v = node.nodeValue;
    if (!v) return;
    const before = v;
    // 去除不间断空格 U+00A0
    v = v.replace(/\u00A0+/g, "");
    // 去除字面量 &nbsp 或  （容错无分号）
    v = v.replace(/ ?/gi, "");
    if (v !== before) node.nodeValue = v;
  }
  // 扫描并清理整棵子树
  function cleanNbspTree(root) {
    const tw = document.createTreeWalker(root, NodeFilter.SHOW_TEXT, null);
    for (let n = tw.nextNode(); n; n = tw.nextNode()) {
      if (!shouldSkip(n)) cleanNbspNode(n);
    }
  }
  // 监听后续变更并持续清理
  function observeNbsp() {
    const mo = new MutationObserver((muts) => {
      for (const m of muts) {
        if (m.type === "characterData") {
          if (!shouldSkip(m.target)) cleanNbspNode(m.target);
        } else if (m.type === "childList") {
          m.addedNodes.forEach((nd) => {
            if (nd.nodeType === 3) {
              if (!shouldSkip(nd)) cleanNbspNode(nd);
            } else if (nd.nodeType === 1) {
              cleanNbspTree(nd);
            }
          });
        }
      }
    });
    mo.observe(document.body, { subtree: true, childList: true, characterData: true });
  }

  // ============== 启动 ==============
  if (document.readyState === "loading") {
    document.addEventListener("DOMContentLoaded", boot);
  } else {
    boot();
  }

  async function boot() {
    try {
      // ① 先全页面清理  
      cleanNbspTree(document.body);
      observeNbsp();

      // ② 确保 opentype.js
      if (!window.opentype) {
        if (AUTO_LOAD_OPENTYPE) {
          await loadScript("https://unpkg.com/opentype.js@1.3.4/dist/opentype.min.js");
        } else {
          console.error("opentype.js 未加载：请先在 HTML 里引入 opentype.min.js，或将 AUTO_LOAD_OPENTYPE 设为 true。");
          return;
        }
      }

      // ③ 加载字体
      const font = await loadFont(FONT_URL).catch(async () => loadFont(FALLBACK_FONT_URL));
      if (!font) {
        console.error("字体加载/解析失败：请确认使用 .ttf/.otf/.woff 且可访问");
        return;
      }

      // ④ 遍历文本节点并替换邮箱
      const roots = document.querySelectorAll(ROOT_SELECTOR);
      roots.forEach((el) => {
        const cs = getComputedStyle(el);
        const fontSizePx = parseFloat(cs.fontSize) || 16;
        const color = cs.color || "#333";

        const getStyle = () => ({ fontSize: fontSizePx, color });

        const walker = document.createTreeWalker(el, NodeFilter.SHOW_TEXT, null);
        const texts = [];
        let n;
        while ((n = walker.nextNode())) texts.push(n);
        texts.forEach((t) => replaceInNodeText(t, getStyle, font));
      });
    } catch (e) {
      console.error("email-svg 渲染失败：", e);
    }
  }

  // ============== 工具函数 ==============
  function loadScript(src) {
    return new Promise((resolve, reject) => {
      const s = document.createElement("script");
      s.src = src;
      s.onload = () => resolve();
      s.onerror = () => reject(new Error("加载脚本失败: " + src));
      document.head.appendChild(s);
    });
  }

  async function loadFont(url) {
    const res = await fetch(url);
    if (!res.ok) throw new Error("字体 HTTP " + res.status);
    const buf = await res.arrayBuffer();

    // 拒绝 woff2：opentype.js 不支持
    const sig = new TextDecoder("ascii").decode(new Uint8Array(buf, 0, 4));
    if (sig === "wOF2") throw new Error("WOFF2 不被 opentype.js 支持，请换 .ttf/.otf/.woff");

    return opentype.parse(buf);
  }

  // 把文本渲染成仅含 <path> 的 SVG dataURI；返回真实字形高度/下降部
  function textToSVGPathDataURI(text, font, opts) {
    const fontSize = (opts && opts.fontSize) || 16;
    const color = (opts && opts.color) || "#333";
    const scale = fontSize / font.unitsPerEm;

    const ascentPx = font.ascender * scale; // 基线到上界
    const descentPx = -font.descender * scale; // 基线到下界（正值）
    const intrinsicH = ascentPx + descentPx; // 真实字形盒高度

    let x = 0,
      d = "",
      prev = null;
    for (const ch of text) {
      const g = font.charToGlyph(ch);
      if (prev) x += font.getKerningValue(prev, g) * scale;
      const p = g.getPath(x, ascentPx, fontSize); // 基线放在 y=ascentPx
      d += (p.toPathData ? p.toPathData(2) : p.toSVG());
      x += g.advanceWidth * scale;
      prev = g;
    }
    const width = Math.ceil(x);
    const height = Math.ceil(intrinsicH);

    const svg = `<svg xmlns="http://www.w3.org/2000/svg" width="${width}" height="${height}"
     viewBox="0 0 ${width} ${height}" role="img" aria-label="protect">
  <path d="${d}" fill="${color}"/>
</svg>`;

    return {
      uri: "data:image/svg+xml;charset=utf-8," + encodeURIComponent(svg),
      intrinsicH,
      descentPx,
    };
  }
// ===== 固定高度配置 =====
const EMAIL_SVG_HEIGHT_MODE = "px"; // "em" 或 "px"
const EMAIL_SVG_HEIGHT = 20;      // 若为 "em" 模式，这里是倍数；若为 "px" 模式，这里是像素值
const EMAIL_SVG_SUPERSAMPLE = 1.5; // 内部超采样倍数(>1提高清晰度)，外部再缩回固定高度

function replaceInNodeText(node, getStyle, font) {
  const text = node.nodeValue;
  if (!PATTERN.test(text)) { PATTERN.lastIndex = 0; return; }
  PATTERN.lastIndex = 0;

  const frag = document.createDocumentFragment();
  let last = 0, m;

  while ((m = PATTERN.exec(text))) {
    const [whole, domainRaw, user] = m;
    const start = m.index;
    const end = start + whole.length;

    if (start > last) frag.appendChild(document.createTextNode(text.slice(last, start)));

    const domain = domainRaw && domainRaw.trim() ? domainRaw.trim() : DEFAULT_DOMAIN;
    const email = `${user}@${domain}`;

    const { fontSize, color } = getStyle();
    // 先按字号生成路径，得到真实字形盒与下降部
    const { uri, intrinsicH, descentPx } = textToSVGPathDataURI(email, font, { fontSize: fontSize * EMAIL_SVG_SUPERSAMPLE, color });

    // —— 目标外显高度（恒定）——
    const targetPx =
      EMAIL_SVG_HEIGHT_MODE === "px"
        ? EMAIL_SVG_HEIGHT
        : Math.max(1, EMAIL_SVG_HEIGHT * fontSize); // "em" 模式 -> 倍数 * 当前字号

    // 内部按超采样生成，外部按固定高度显示
    const cssHeight = Math.round(targetPx);
    // 基线对齐：随着外显缩放，下降部也按比例缩放
    const scale = targetPx / (intrinsicH * EMAIL_SVG_SUPERSAMPLE);
    const vAlign = (-descentPx * EMAIL_SVG_SUPERSAMPLE * scale).toFixed(2) + "px";

    const img = document.createElement("img");
    img.src = uri;
    img.alt = "";
    img.decoding = "async";
    img.loading = "lazy";
    img.style.height = cssHeight + "px";  // —— 恒定高度 ——（关键）
    img.style.width = "auto";
    img.style.verticalAlign = vAlign;     // 基线对齐
    img.style.userSelect = "none";
    img.style.display = "inline-block";

    // 用零行高包裹，避免撑高行盒
    const wrap = document.createElement("span");
    wrap.style.display = "inline-block";
    wrap.style.lineHeight = "0";
    wrap.appendChild(img);

    frag.appendChild(wrap);
    last = end;
  }

  if (last < text.length) frag.appendChild(document.createTextNode(text.slice(last)));
  node.parentNode.replaceChild(frag, node);
}


})();