Two endpoints. One honest ad slot.

// server.js — one endpoint: ChatGPT reply + one LoreAds ad.
// ENV: OPENAI_API_KEY, LOREADS_API_KEY
app.post("/api/chat", async (req, res) => {
  const { messages } = req.body; // [{ role, content }]

  // 1. Reply from ChatGPT
  const ai = await fetch("https://api.openai.com/v1/chat/completions", {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      Authorization: `Bearer ${process.env.OPENAI_API_KEY}`,
    },
    body: JSON.stringify({ model: "gpt-4o-mini", messages }),
  });
  const aiJson = await ai.json();
  const reply = aiJson.choices[0].message.content;

  // 2. Topic signal from the user's last message only (not the transcript)
  const topicSignal = String(messages.at(-1).content).slice(0, 300);

  // 3. One sponsored recommendation (billed as a single impression)
  const lr = await fetch("https://your-loreads-domain/api/serve-ad", {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({
      api_key: process.env.LOREADS_API_KEY,
      context: topicSignal,
    }),
  });
  const { ad } = await lr.json();

  // 4. Return both — render the ad beneath the answer when present
  res.json({ reply, ad });
});

// SERVER-SIDE ONLY. Store your API key as LOREADS_API_KEY.
app.post("/api/loreads-ad", async (req, res) => {
  const response = await fetch("https://your-loreads-domain/api/serve-ad", {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({
      api_key: process.env.LOREADS_API_KEY,
      context: String(req.body.topicSignal || "").slice(0, 300),
    }),
  });
  const payload = await response.json();
  res.status(response.status).json({ ad: payload.ad || null });
});

// Browser: call your own backend route; never expose the LoreAds key.
async function renderSponsoredCard({ topicSignal, mount }) {
  const response = await fetch("/api/loreads-ad", {
    method: "POST", headers: { "Content-Type": "application/json" },
    body: JSON.stringify({ topicSignal }),
  });
  const { ad } = await response.json();
  if (!ad) return;
  const card = document.createElement("section");
  const label = document.createElement("span"); label.textContent = ad.disclosure;
  const headline = document.createElement("p"); headline.textContent = ad.headline;
  const body = document.createElement("p"); body.textContent = ad.body;
  const link = document.createElement("a"); link.href = ad.click_url;
  link.rel = "sponsored noopener"; link.textContent = ad.cta_label;
  card.append(label, headline, body, link); mount.replaceChildren(card);
}