memind/plaza-embed.mjs

/**
 * Plaza iframe embed helpers — full-page iframe height sync for publication pages.
 */

export const PLAZA_EMBED_QUERY = 'embed=plaza';

export function isPlazaEmbedRequest(query = {}) {
  return String(query?.embed ?? '').toLowerCase() === 'plaza';
}

export function publishedPageCspForEmbed(isFullHtml) {
  if (isFullHtml) {
    return "default-src 'none'; style-src 'unsafe-inline' https:; img-src data: https:; font-src https: data:; base-uri 'none'; form-action 'self'; frame-ancestors *; script-src 'unsafe-inline'";
  }
  return "default-src 'none'; style-src 'unsafe-inline'; img-src data:; font-src 'none'; base-uri 'none'; form-action 'self'; frame-ancestors *; script-src 'unsafe-inline'";
}

const EMBED_BOOTSTRAP = `<script id="plaza-embed-bootstrap">(function(){
  if(window.parent===window)return;
  var d=document;
  function blocks(){
    var out=[],hero=d.querySelector('.hero');
    if(hero)out.push(hero);
    d.querySelectorAll('.section,.quote-section').forEach(function(el){out.push(el);});
    var foot=d.querySelector('.footer');
    if(foot)out.push(foot);
    return out.length?out:[d.body];
  }
  function fullHeight(){
    var body=d.body;
    var measured=0;
    var els=blocks();
    for(var i=0;i<els.length;i++){
      var el=els[i];
      measured=Math.max(measured,el.offsetTop+el.offsetHeight);
    }
    if(body&&body.lastElementChild){
      var last=body.lastElementChild;
      measured=Math.max(measured,last.offsetTop+last.offsetHeight);
    }
    measured=Math.max(measured,d.documentElement.scrollHeight,body?body.scrollHeight:0,420);
    return Math.min(measured,16000);
  }
  function restoreBlock(block){
    if(!block)return;
    block.querySelectorAll('[data-plaza-defer-bg]').forEach(function(el){
      el.style.backgroundImage=el.dataset.plazaDeferBg;
      delete el.dataset.plazaDeferBg;
    });
    block.querySelectorAll('[data-plaza-defer-hero-bg]').forEach(function(el){
      var bg=el.dataset.plazaDeferHeroBg;
      if(!bg)return;
      if(bg.indexOf('url(')>=0)el.style.backgroundImage=bg;
      else el.style.background=bg;
      delete el.dataset.plazaDeferHeroBg;
    });
  }
  function reportHeight(){
    var b=blocks();
    window.parent.postMessage({
      type:'plaza:embed-section',
      count:b.length,
      height:fullHeight(),
      total:b.length
    },'*');
  }
  function showAll(){
    var b=blocks();
    for(var i=0;i<b.length;i++){
      b[i].style.display='';
      b[i].style.visibility='';
      restoreBlock(b[i]);
    }
    reportHeight();
  }
  var style=d.createElement('style');
  style.textContent='html,body{overflow:hidden!important;margin:0}';
  d.head.appendChild(style);
  function scheduleReport(){
    showAll();
    requestAnimationFrame(function(){
      requestAnimationFrame(function(){
        reportHeight();
      });
    });
  }
  if(d.readyState==='loading'){
    d.addEventListener('DOMContentLoaded',scheduleReport);
  }else{
    scheduleReport();
  }
  window.addEventListener('load',function(){scheduleReport();});
  new ResizeObserver(function(){reportHeight();}).observe(d.documentElement);
})();</script>`;

const EMBED_LAYOUT_OVERRIDES =
  '<style id="plaza-embed-overrides">.section,.quote-section,.footer{content-visibility:visible!important;contain-intrinsic-size:auto!important}</style>';

/** Remove inline CSP meta tags that block plaza-embed-bootstrap (HTTP CSP header applies instead). */
export function stripPublicationHtmlCspMeta(html) {
  return String(html ?? '').replace(
    /<meta\s+http-equiv\s*=\s*["']Content-Security-Policy["'][^>]*>/gi,
    '',
  );
}

/** Prepare stored publication HTML for Plaza iframe embed. */
export function preparePublicationHtmlForEmbed(html) {
  let source = stripPublicationHtmlCspMeta(html);
  if (!source.includes('id="plaza-embed-overrides"') && /<head[^>]*>/i.test(source)) {
    source = source.replace(/<head([^>]*)>/i, `<head$1>${EMBED_LAYOUT_OVERRIDES}`);
  }
  return injectPlazaEmbedBootstrap(source);
}

export function injectPlazaEmbedBootstrap(html) {
  const source = String(html ?? '');
  if (source.includes('id="plaza-embed-bootstrap"')) return source;
  if (/<\/body>/i.test(source)) {
    return source.replace(/<\/body>/i, `${EMBED_BOOTSTRAP}</body>`);
  }
  return `${source}${EMBED_BOOTSTRAP}`;
}

export function appendPlazaEmbedQuery(url) {
  const value = String(url ?? '').trim();
  if (!value) return value;
  if (value.includes(PLAZA_EMBED_QUERY)) return value;
  return value.includes('?') ? `${value}&${PLAZA_EMBED_QUERY}` : `${value}?${PLAZA_EMBED_QUERY}`;
}