send_service_message.js

const { onRequest } = require("firebase-functions/v2/https");
const fetch = require("node-fetch");

/**
 * ENV (ควรย้ายไป .env หรือ Firebase Config)
 */
const CLIENT_ID = "xxxxx";         // ใส่ Channel ID
const CLIENT_SECRET = "xxxxx";     // ใส่ Channel Secret

/**
 * 1. Get Stateless Token
 */
async function getStatelessToken() {
  const params = new URLSearchParams({
    grant_type: "client_credentials",
    client_id: CLIENT_ID,
    client_secret: CLIENT_SECRET,
  });

  const res = await fetch("https://api.line.me/oauth2/v3/token", {
    method: "POST",
    headers: { "Content-Type": "application/x-www-form-urlencoded" },
    body: params,
  });

  if (!res.ok) throw new Error("Failed to get stateless token");

  const data = await res.json();
  return data.access_token;
}

/**
 * 2. Get Notifier Token
 */
async function getNotifierToken(statelessToken, liffAccessToken) {
  const res = await fetch(
    "https://api.line.me/message/v3/notifier/token",
    {
      method: "POST",
      headers: {
        "Content-Type": "application/json",
        Authorization: `Bearer ${statelessToken}`,
      },
      body: JSON.stringify({
        liffAccessToken: liffAccessToken,
      }),
    }
  );

  if (!res.ok) throw new Error("Failed to get notifier token");

  const data = await res.json();
  return data.notificationToken;
}

/**
 * 3. Send Service Message
 */
async function sendServiceMessage(statelessToken, notifierToken) {
  const res = await fetch(
    "https://api.line.me/message/v3/notifier/send?target=service",
    {
      method: "POST",
      headers: {
        "Content-Type": "application/json",
        Authorization: `Bearer ${statelessToken}`,
      },
      body: JSON.stringify({
        templateName: "join_d_m_en",
        params: {
          entry_date: "4 March 2025 09:41",
          btn1_url: "https://line.me",
        },
        notificationToken: notifierToken,
      }),
    }
  );

  if (!res.ok) throw new Error("Failed to send service message");

  return await res.json();
}

/**
 * 🔥 MAIN API
 * POST /sendServiceMessage
 * body: { liffAccessToken }
 */
exports.sendServiceMessage = onRequest(async (req, res) => {
  try {
    const { liffAccessToken } = req.body;

    if (!liffAccessToken) {
      return res.status(400).json({ error: "Missing liffAccessToken" });
    }

    // Step 1
    const statelessToken = await getStatelessToken();

    // Step 2
    const notifierToken = await getNotifierToken(
      statelessToken,
      liffAccessToken
    );

    // Step 3
    const result = await sendServiceMessage(
      statelessToken,
      notifierToken
    );

    res.json({
      success: true,
      statelessToken,
      notifierToken,
      result,
    });
  } catch (err) {
    res.status(500).json({
      error: err.message || "Internal Error",
    });
  }
});