console.log("[YT-Erfasser] Content Script geladen");

const sentUrls = new Set();

function extractVideoFromCard(element) {
  const link = element.querySelector('a[href*="/watch?v="]');
  if (!link) return null;

  const match = link.href.match(/[?&]v=([^&]+)/);
  if (!match) return null;

  const title = element.querySelector("h3 a")?.textContent?.trim();
  if (!title) return null;

  const thumbnail = element.querySelector('a[href*="/watch?v="] img')?.src;
  const youtuber = element.querySelector('a[href^="/@"]')?.textContent?.trim() || "Unbekannt";

  return {
    title,
    youtuber,
    thumbnail_url: thumbnail || `https://img.youtube.com/vi/${match[1]}/hqdefault.jpg`,
    youtube_url: `https://www.youtube.com/watch?v=${match[1]}`,
  };
}

function collectVideos(elements) {
  const videos = [];
  for (const el of elements) {
    const video = extractVideoFromCard(el);
    if (!video) continue;
    if (sentUrls.has(video.youtube_url)) continue;
    sentUrls.add(video.youtube_url);
    videos.push(video);
  }
  return videos;
}

// --- Debounced Batch-Versand ---

let pendingVideos = [];
let sendTimer = null;

function queueVideos(videos) {
  pendingVideos.push(...videos);
  if (!sendTimer) {
    sendTimer = setTimeout(() => {
      if (pendingVideos.length > 0) {
        console.log(`[YT-Erfasser] ${pendingVideos.length} Videos senden`);
        browser.runtime.sendMessage(pendingVideos);
      }
      pendingVideos = [];
      sendTimer = null;
    }, 250);
  }
}

// --- IntersectionObserver: nur sichtbare Cards erfassen ---

const visibilityObserver = new IntersectionObserver((entries) => {
  const cards = entries.filter((e) => e.isIntersecting).map((e) => e.target);
  if (cards.length > 0) {
    queueVideos(collectVideos(cards));
  }
}, { threshold: 0.5 });

function observeCard(el) {
  visibilityObserver.observe(el);
}

// --- MutationObserver: neue Cards registrieren ---

const mutationObserver = new MutationObserver((mutations) => {
  for (const mutation of mutations) {
    for (const node of mutation.addedNodes) {
      if (node.nodeType !== Node.ELEMENT_NODE) continue;
      if (node.matches?.("ytd-rich-item-renderer, ytd-video-renderer")) {
        observeCard(node);
      }
      node.querySelectorAll?.("ytd-rich-item-renderer, ytd-video-renderer").forEach(observeCard);
    }
  }
});

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

// --- SPA Navigation ---

document.addEventListener("yt-navigate-finish", () => {
  sentUrls.clear();
  setTimeout(() => {
    document.querySelectorAll("ytd-rich-item-renderer, ytd-video-renderer").forEach(observeCard);
  }, 500);
});

// --- Init ---

document.querySelectorAll("ytd-rich-item-renderer, ytd-video-renderer").forEach(observeCard);