!function (global) {
  const SmartLoad = {
    assets: [],
    functions: [],
    loaded: new Set(),
    isLibraryAvailable: n => typeof global[n] !== "undefined"
  };

  const EVENTS = ["keydown", "mousemove", "wheel", "touchmove", "touchstart", "touchend"];
  const MAX_RETRIES = 3;
  let hasStarted = false, timeoutHandle;

  const sleep = ms => new Promise(r => setTimeout(r, ms));
  const validURL = /^(https?:)?\/\/[^\s]+$/;

  async function loadAsset({ type, src, location = "body", callback }) {
    if (SmartLoad.loaded.has(src)) return;

    for (let attempt = 1; attempt <= MAX_RETRIES; attempt++) {
      try {
        await new Promise((resolve, reject) => {
          let el;
          switch (type) {
            case "script":
              el = document.createElement("script");
              el.src = src;
              el.async = false; // maintain order
              el.onload = resolve;
              el.onerror = reject;
              (location === "head" ? document.head : document.body).appendChild(el);
              break;

            case "style":
              el = document.createElement("link");
              el.rel = "stylesheet";
              el.href = src;
              el.onload = resolve;
              el.onerror = reject;
              document.head.appendChild(el);
              break;
          }
        });

        SmartLoad.loaded.add(src);
        callback?.();
        return;

      } catch {
        const delay = Math.min(2 ** attempt * 200, 4000);
        console.warn(`[SmartLoad] Retry ${attempt}/${MAX_RETRIES} for ${src} in ${delay}ms`);
        await sleep(delay);
      }
    }

    console.error(`[SmartLoad] Failed to load after ${MAX_RETRIES} attempts: ${src}`);
  }

  async function loadSequential(assets, onComplete) {
    for (const asset of assets) await loadAsset(asset);
    onComplete?.();
  }

  function processSmartLoadTags() {
    const els = document.querySelectorAll("[smartload]");
    const assets = [];

    els.forEach(el => {
      const src = el.getAttribute("smartload");
      if (!validURL.test(src)) return console.error(`[SmartLoad] Invalid URL: ${src}`);
      const tag = el.tagName;

      if (tag === "SCRIPT") assets.push({ type: "script", src });
      else if (tag === "LINK") assets.push({ type: "style", src });
      else if (tag === "IFRAME") observeIframe(el, src);

      el.removeAttribute("smartload");
    });

    if (assets.length) loadSequential(assets);
  }

  function observeIframe(el, src) {
    const obs = new IntersectionObserver(entries => {
      entries.forEach(entry => {
        if (entry.isIntersecting) {
          entry.target.src = src;
          obs.unobserve(entry.target);
        }
      });
    });
    obs.observe(el);
  }

  function setupSmartVideos() {
    const videoDivs = document.querySelectorAll("[smartload-video]");
    const isSafari = /^((?!chrome|android).)*safari/i.test(navigator.userAgent);

    videoDivs.forEach(div => {
      const videoUrl = div.getAttribute("smartload-video");
      if (!validURL.test(videoUrl)) {
        console.error(`[SmartLoad] Invalid video URL: ${videoUrl}`);
        return;
      }

      // accessibility + cursor
      div.setAttribute("role", "button");
      div.setAttribute("tabindex", "0");
      div.setAttribute("aria-label", "Play video");
      div.style.cursor = "pointer";

      const loadVideo = () => {
        let videoFinalUrl = videoUrl;
        // Add enablejsapi=1 only for Safari
        if (isSafari && !/[?&]enablejsapi=/.test(videoFinalUrl)) {
          videoFinalUrl += (videoFinalUrl.includes("?") ? "&" : "?") + "enablejsapi=1";
        }
        
        const iframe = document.createElement("iframe");
        iframe.src = videoFinalUrl;
        iframe.allow = "accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture";
        iframe.allowFullscreen = true;
        iframe.frameBorder = "0";
        iframe.width = "100%";
        iframe.height = "100%";
        iframe.setAttribute("class", "iframe-youtube");
        iframe.style.display = "block"; // ensure visibility

        div.innerHTML = "";  // Clear placeholder content
        div.appendChild(iframe);
        
        iframe.offsetHeight; // Force layout
        requestAnimationFrame(() => {
          iframe.style.transform = "translateZ(0)";
          iframe.style.willChange = "transform";
        });

        // Safari autoplay helper (use JS API)
        if (isSafari) {
          iframe.addEventListener("load", () => {
            try {
              iframe.contentWindow?.postMessage(
                JSON.stringify({ event: "command", func: "playVideo", args: [] }),
                "*"
              );
            } catch (err) {
              console.warn("[SmartLoad] Safari playVideo postMessage failed:", err);
            }
          });
        }

        div.removeAttribute("role", "button");
        div.removeAttribute("tabindex", "0");
        div.removeAttribute("aria-label", "Play video");
        div.removeAttribute("smartload-video");
        div.style.cursor = "default";
      };

      // The `{ once: true }` ensures this only runs the first time
      div.addEventListener("click", loadVideo, { once: true });
    });
  }

  function triggerLoad() {
    if (hasStarted) return;
    hasStarted = true;
    clearTimeout(timeoutHandle);
    loadSequential(SmartLoad.assets, () => {
      SmartLoad.functions.forEach(fn => fn instanceof Function && fn());
      processSmartLoadTags();
      setupSmartVideos();
    });
  }

  document.addEventListener("DOMContentLoaded", () => {
    processSmartLoadTags();
    setupSmartVideos();
    EVENTS.forEach(e => document.addEventListener(e, triggerLoad, { once: true }));
    timeoutHandle = setTimeout(triggerLoad, 10000);
  });

  global.smartload = SmartLoad;
}(this);