// 点击"下载视频"时执行：优先从页面内嵌数据 RENDER_DATA 精确提取当前视频地址，
// 其次才用嗅探列表兜底。
(function () {
  try {
    var pageUrl = location.href;

    // 从 URL 提取视频 ID
    var videoId = "";
    var m = pageUrl.match(/[?&]modal_id=(\d+)/);
    if (m) videoId = m[1];
    if (!videoId) {
      var m0 = pageUrl.match(/[?&]aweme_id=(\d+)/);
      if (m0) videoId = m0[1];
    }
    if (!videoId) {
      var m2 = pageUrl.match(/\/(?:video|note)\/(\d+)/);
      if (m2) videoId = m2[1];
    }

    // === 方案一：从 RENDER_DATA 里精确找当前视频的播放地址 ===
    var renderVideoUrl = "";
    var renderAudioUrl = "";
    try {
      var rd = document.getElementById("RENDER_DATA");
      if (rd && rd.textContent) {
        var decoded = decodeURIComponent(rd.textContent);
        // 在 JSON 里找 aweme_id 等于 videoId 的节点，提取其 video.play_addr 或 play_addr 列表
        // 用正则粗匹配，避免完整 JSON 解析的复杂性
        var idx = decoded.indexOf(videoId);
        while (idx >= 0) {
          // 在这个 ID 附近找 playApi / play_addr / url_list
          var chunk = decoded.substring(Math.max(0, idx - 200), idx + 5000);
          // 找 DASH 格式的视频轨和音频轨
          var vMatches = chunk.match(/https?:\/\/[^"\\]+media-video[^"\\]*/gi);
          var aMatches = chunk.match(/https?:\/\/[^"\\]+media-audio[^"\\]*/gi);
          if (vMatches && vMatches.length) {
            renderVideoUrl = vMatches[vMatches.length - 1];
            if (aMatches && aMatches.length) {
              renderAudioUrl = aMatches[aMatches.length - 1];
            }
            break;
          }
          // 找普通 mp4 直链
          var mp4Matches = chunk.match(/https?:\/\/[^"\\]*\.mp4[^"\\]*/gi);
          if (mp4Matches && mp4Matches.length) {
            renderVideoUrl = mp4Matches[mp4Matches.length - 1];
            break;
          }
          idx = decoded.indexOf(videoId, idx + 1);
        }
      }
    } catch (e) { /* RENDER_DATA 解析失败就走嗅探兜底 */ }

    // === 方案二：选正在播放的 <video> 元素 ===
    var vids = Array.prototype.slice.call(document.querySelectorAll("video"));
    var best = null;
    for (var i = 0; i < vids.length; i++) {
      var v = vids[i];
      if (!v.paused && v.currentTime > 0) { best = v; break; }
    }
    if (!best) {
      for (var j = 0; j < vids.length; j++) {
        var v2 = vids[j];
        if (v2.videoWidth > 0 || (!isNaN(v2.duration) && v2.duration > 0 && v2.currentTime > 0)) {
          best = v2;
          break;
        }
      }
    }
    if (!best) best = vids[0];

    var current = "";
    var playable = true;
    if (best) {
      current = best.currentSrc || best.src || "";
      if (!current) {
        var s = best.querySelector && best.querySelector("source");
        if (s) current = s.src || s.getAttribute("src") || "";
      }
      if (best.networkState === 0) playable = false;
    }

    // === 方案三：嗅探列表兜底 ===
    var all = window.__mediaUrls || [];
    var videoTracks = [];
    var audioTracks = [];
    var otherMedia = [];
    for (var k = 0; k < all.length; k++) {
      var u = all[k];
      if (/media-video/i.test(u)) videoTracks.push(u);
      else if (/media-audio/i.test(u)) audioTracks.push(u);
      else otherMedia.push(u);
    }

    function pickLast(arr) {
      return arr.length ? arr[arr.length - 1] : "";
    }

    var dashVideo = pickLast(videoTracks);
    var dashAudio = pickLast(audioTracks);

    // 如果 RENDER_DATA 找到了，优先用它
    if (renderVideoUrl) {
      dashVideo = renderVideoUrl;
      if (renderAudioUrl) dashAudio = renderAudioUrl;
    }

    var title = document.title || "";
    var h1 = document.querySelector("h1");
    if (h1 && h1.innerText) title = h1.innerText;

    return JSON.stringify({
      current: current || "",
      playable: playable,
      usesMse: !!window.__usesMse || /^blob:/i.test(current),
      title: title,
      pageUrl: pageUrl,
      videoId: videoId,
      sniffed: otherMedia.slice(-60),
      dashVideo: dashVideo,
      dashAudio: dashAudio,
      m3u8Blobs: (window.__m3u8Blobs || []).slice(-1),
    });
  } catch (e) {
    return JSON.stringify({
      current: "",
      title: document.title || "",
      pageUrl: location.href,
      error: String(e),
    });
  }
})();