// ── Bounded decoded-image lifecycle ─────────────────────────────────────────
// Native loading="lazy" controls network work, but browsers may retain decoded
// pixels for every image that has entered the viewport. Keep a small LRU of
// visible library images and drop src from old, off-screen elements so their
// decoded surfaces can be reclaimed. data-ttvc-src restores them on re-entry.
(function () {
  'use strict';
  var root = window.TTVC = window.TTVC || {};
  var entries = new Map();
  var visible = new Set();
  var observer = 'IntersectionObserver' in window ? new IntersectionObserver(function (records) {
    records.forEach(function (record) {
      var img = record.target;
      if (record.isIntersecting) {
        visible.add(img);
        var source = img.dataset.ttvcSrc;
        if (source && !img.getAttribute('src')) img.setAttribute('src', source);
        entries.delete(img); entries.set(img, Date.now());
      } else {
        visible.delete(img);
      }
    });
    evict();
  }, { rootMargin: '160px' }) : null;

  function limit() {
    return typeof window.ttvcIsLowMemoryDevice === 'function' && window.ttvcIsLowMemoryDevice() ? 24 : 64;
  }
  function evict() {
    // Disconnected nodes are no longer useful cache entries.
    entries.forEach(function (_, img) { if (!img.isConnected) entries.delete(img); });
    while (entries.size > limit()) {
      var candidate = null;
      for (var img of entries.keys()) {
        if (!visible.has(img)) { candidate = img; break; }
      }
      if (!candidate) break; // never evict an image currently near the viewport
      entries.delete(candidate);
      if (candidate.getAttribute('src')) candidate.dataset.ttvcSrc = candidate.getAttribute('src');
      candidate.removeAttribute('src');
    }
  }
  function observeImages(container) {
    if (!container) return;
    container.querySelectorAll('img').forEach(function (img) {
      if (!img.dataset.ttvcSrc && img.getAttribute('src')) img.dataset.ttvcSrc = img.getAttribute('src');
      if (observer && !img.dataset.ttvcObserved) {
        img.dataset.ttvcObserved = '1';
        observer.observe(img);
      }
      entries.delete(img); entries.set(img, Date.now());
    });
    evict();
  }
  root.imageCache = { observe: observeImages, evict: evict, size: function () { return entries.size; } };
  window.ttvcObserveImages = observeImages;
})();