index.js

const express = require("express");
const Stripe = require("stripe");
const { STRIPE_SECRET_KEY, STRIPE_ENDPOINT_SECRET } = require("./config");

const stripe = new Stripe(STRIPE_SECRET_KEY);
const app = express();

// Middleware
app.use(express.json({
  verify: (req, res, buf) => {
    if (req.originalUrl.startsWith("/payment-webhook")) {
      req.rawBody = buf.toString();
    }
  }
}));
app.use(express.urlencoded({ extended: true }));
app.use(express.static(__dirname + "/public"));


// Routes
app.post("/create-payment-session", async (req, res) => {
  try {
    const { amount, currency } = req.body;
    const session = await stripe.checkout.sessions.create({
      payment_method_types: ["card"],
      line_items: [
        {
          price_data: {
            currency,
            product_data: {
              name: "Technow Pro Subscription",
              description: "Monthly subscription to Technow Pro",
              images: ["https://picsum.photos/200/300"]
            },
            unit_amount: amount * 100 // accepts amount in cents
          },
          quantity: 1
        }
      ],
      payment_intent_data: {
        // metadata to store custom data and map in webhook
        // can only store string values, so stringify if needed
        metadata: {
          order_id: "12345",
          user_id: "67890"
        }
      },
      mode: "payment",
      success_url: `${req.headers.origin}/payment-success`,
      cancel_url: `${req.headers.origin}/payment-cancel`
    });
    res.status(200).json({ id: session.id, url: session.url });
  } catch (error) {
    console.error("Error creating order:", error);
    res.status(500).json({
      code: "Internal server error",
      message: error.message
    });
  }
});

app.post("/payment-webhook", async (req, res) => {
  console.log("Received webhook payload:", req.body);
  console.log("Received stripe webhook event");
  const sig = req.headers["stripe-signature"];
  let event;
  try {
    event = stripe.webhooks.constructEvent(
      req.rawBody, // raw request body. if express.raw() middleware is used, use req.body
      sig,
      STRIPE_ENDPOINT_SECRET
    );
  } catch (err) {
    console.log("Webhook Error: ", err.message);
    return res.status(400).send(`Webhook Error: ${err.message}`);
  }

  // Handle the event
  switch (event.type) {
    case "payment_intent.succeeded":
      console.log("Received payment_intent.succeeded event");
      const paymentIntent = event.data.object;
      console.log("Payment success intent:", paymentIntent);
      // verify payment and update order status in database
      // send 200 res to acknowledge receipt of event and avoid retries
      res.status(200).json({ received: true });
      break;
    default:
      console.log(`Unhandled event type ${event.type}`);
      res.status(200).json({ received: true });
  }
});

app.get("/", (req, res) => res.send("Hello World"));
app.get("/purchase", (req, res) =>
  res.sendFile(__dirname + "/public/purchase.html")
);
app.get("/payment-cancel", (req, res) =>
  res.sendFile(__dirname + "/public/payment-cancel.html")
);
app.get("/payment-success", (req, res) =>
  res.sendFile(__dirname + "/public/payment-success.html")
);

const PORT = process.env.PORT || 3000;
app.listen(PORT, () =>
  console.log(`Server is running on http://localhost:${PORT}`)
);