// Investor RPG — YouTube 內容擷取
// 執行在 YouTube 頁面上，利用使用者的登入 session 取得字幕

const API_HOST = "http://localhost:3000";
let injectButton = null;

function extractVideoId() {
  const m = window.location.pathname.match(/\/watch\/([a-zA-Z0-9_-]{11})/) ||
    window.location.search.match(/[?&]v=([a-zA-Z0-9_-]{11})/);
  return m ? m[1] : null;
}

function extractPlaylistId() {
  const m = window.location.search.match(/[?&]list=([a-zA-Z0-9_-]+)/);
  return m ? m[1] : null;
}

function getVideoTitle() {
  const el = document.querySelector("h1 yt-formatted-string") ||
    document.querySelector("#title h1") ||
    document.querySelector("meta[itemprop='name']");
  return el?.textContent?.trim() || el?.getAttribute("content") || document.title.replace(" - YouTube", "");
}

function getChannelName() {
  const el = document.querySelector("#owner #channel-name a") ||
    document.querySelector("ytd-channel-name a") ||
    document.querySelector("link[itemprop='name'][href^='http']");
  return el?.textContent?.trim() || el?.getAttribute("content") || "";
}

function getUploadDate() {
  const el = document.querySelector("meta[itemprop='datePublished']") ||
    document.querySelector("#info-strings yt-formatted-string");
  return el?.getAttribute("content") || el?.textContent?.trim() || "";
}

function getThumbnail() {
  const el = document.querySelector("meta[property='og:image']");
  return el?.getAttribute("content") || "";
}

function injectCaptureButton() {
  if (injectButton || !extractVideoId()) return;

  injectButton = document.createElement("button");
  injectButton.textContent = "📥 擷取到 RPG";
  injectButton.style.cssText = `
    background: #2a6c3b; color: #fff; border: none; border-radius: 18px;
    padding: 6px 16px; font-size: 13px; cursor: pointer;
    margin-left: 8px; white-space: nowrap; font-weight: 500;
    transition: background .15s;
  `;
  injectButton.onmouseenter = () => injectButton.style.background = "#1e7e34";
  injectButton.onmouseleave = () => injectButton.style.background = "#2a6c3b";

  injectButton.onclick = async () => {
    injectButton.textContent = "擷取中...";
    injectButton.disabled = true;
    try {
      const result = await captureVideo();
      injectButton.textContent = `✓ ${result.count || "已送出"}`;
      setTimeout(() => {
        injectButton.textContent = "📥 擷取到 RPG";
        injectButton.disabled = false;
      }, 3000);
    } catch (err) {
      injectButton.textContent = `✕ ${err.message.slice(0, 20)}`;
      injectButton.style.background = "#a13a3a";
      setTimeout(() => {
        injectButton.textContent = "📥 擷取到 RPG";
        injectButton.style.background = "#2a6c3b";
        injectButton.disabled = false;
      }, 3000);
    }
  };

  const waitForTarget = () => {
    const target = document.querySelector("#menu-container") ||
      document.querySelector("#top-level-buttons-computed") ||
      document.querySelector("#actions-inner");
    if (target) {
      target.appendChild(injectButton);
    } else {
      setTimeout(waitForTarget, 500);
    }
  };
  waitForTarget();
}

async function fetchTranscriptFromPage() {
  const videoId = extractVideoId();
  if (!videoId) return "";

  try {
    const apiKey = "";
    const response = await fetch(`https://youtubetranscript.com/api?vid=${videoId}`, {
      signal: AbortSignal.timeout(8000),
    });
    if (response.ok) {
      const data = await response.json();
      return (data.segments || []).map(s => s.text).join(" ");
    }
  } catch {}

  try {
    const pageResponse = await fetch(`https://www.youtube.com/watch?v=${videoId}`, {
      credentials: "include",
      signal: AbortSignal.timeout(8000),
    });
    const html = await pageResponse.text();
    const capsMatch = html.match(/"captionTracks":\s*(\[.*?\])/);
    if (capsMatch) {
      const tracks = JSON.parse(capsMatch[1]);
      const zhTrack = tracks.find(t => t.languageCode?.startsWith("zh")) || tracks[0];
      if (zhTrack?.baseUrl) {
        const subResp = await fetch(zhTrack.baseUrl, { signal: AbortSignal.timeout(8000) });
        const subText = await subResp.text();
        return subText.replace(/<\s*\/?\s*[^>]+>/g, "").replace(/[\d:,.\s]+-->[\d:,.\s]+/g, "").replace(/WEBVTT.*?\n/, "").trim();
      }
    }
  } catch {}

  return "";
}

function extractDescription() {
  const el = document.querySelector("#description yt-formatted-string") ||
    document.querySelector("#description");
  return el?.textContent?.trim()?.slice(0, 1000) || "";
}

async function captureVideo() {
  const videoId = extractVideoId();
  if (!videoId) throw new Error("找不到影片 ID");

  const title = getVideoTitle();
  const channel = getChannelName();
  const uploadDate = getUploadDate();
  const thumbnail = getThumbnail();
  const description = extractDescription();
  const transcript = await fetchTranscriptFromPage();

  const payload = {
    kind: "youtube",
    title,
    url: window.location.href,
    videoId,
    transcript,
    metadata: {
      channel,
      uploadDate,
      thumbnail,
      description,
      title,
      videoId,
    },
  };

  const res = await fetch(`${API_HOST}/api/content/capture`, {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify(payload),
  });

  if (!res.ok) {
    const err = await res.json().catch(() => ({}));
    throw new Error(err.message || `伺服器回應 ${res.status}`);
  }

  return await res.json();
}

let lastUrl = "";
function checkForVideoChange() {
  const currentUrl = window.location.href;
  if (currentUrl !== lastUrl) {
    lastUrl = currentUrl;
    if (injectButton) {
      injectButton.remove();
      injectButton = null;
    }
    if (extractVideoId()) {
      setTimeout(injectCaptureButton, 1000);
    }
  }
}

setInterval(checkForVideoChange, 1500);
setTimeout(injectCaptureButton, 1500);