How to Create a Virtual Gift Card System in FlutterFlow

1// Cloud Functions: Gift Card System
2const functions = require('firebase-functions');
3const admin = require('firebase-admin');
4const crypto = require('crypto');
5const stripe = require('stripe')(functions.config().stripe.secret_key);
6admin.initializeApp();
7
8function generateCode() {
9  return crypto.randomBytes(8).toString('hex').toUpperCase().slice(0, 16);
10}
11
12// Create Stripe Checkout for gift card purchase
13exports.purchaseGiftCard = functions.https.onCall(async (data, context) => {
14  if (!context.auth) throw new functions.https.HttpsError('unauthenticated', 'Login required');
15  const { amount, recipientEmail, recipientName, designTemplate, personalMessage } = data;
16  if (amount < 5 || amount > 500) {
17    throw new functions.https.HttpsError('invalid-argument', 'Amount must be $5-$500');
18  }
19  const session = await stripe.checkout.sessions.create({
20    mode: 'payment',
21    line_items: [{
22      price_data: {
23        currency: 'usd',
24        product_data: { name: `$${amount} Gift Card` },
25        unit_amount: amount * 100,
26      },
27      quantity: 1,
28    }],
29    metadata: {
30      userId: context.auth.uid, recipientEmail, recipientName,
31      designTemplate, personalMessage: personalMessage || '',
32    },
33    success_url: 'https://yourapp.com/gift-card-success',
34    cancel_url: 'https://yourapp.com/gift-cards',
35  });
36  return { url: session.url };
37});
38
39// Webhook: create card + send email after payment
40exports.giftCardWebhook = functions.https.onRequest(async (req, res) => {
41  const sig = req.headers['stripe-signature'];
42  let event;
43  try {
44    event = stripe.webhooks.constructEvent(
45      req.rawBody, sig, functions.config().stripe.gc_webhook_secret
46    );
47  } catch (err) { return res.status(400).send(`Error: ${err.message}`); }
48
49  if (event.type === 'checkout.session.completed') {
50    const s = event.data.object;
51    const m = s.metadata;
52    const code = generateCode();
53    const amt = s.amount_total / 100;
54    await admin.firestore().collection('gift_cards').add({
55      code, initialBalance: amt, currentBalance: amt,
56      purchasedBy: m.userId, recipientEmail: m.recipientEmail,
57      recipientName: m.recipientName, designTemplate: m.designTemplate,
58      isActivated: true, expiresAt: null,
59      createdAt: admin.firestore.FieldValue.serverTimestamp(),
60    });
61    await admin.firestore().collection('mail').add({
62      to: m.recipientEmail,
63      message: {
64        subject: `You received a $${amt} gift card!`,
65        html: `<p>Hi ${m.recipientName}, your gift card code is: <strong>${code}</strong></p>`,
66      },
67    });
68  }
69  res.status(200).send('OK');
70});
71
72// Redeem gift card at checkout
73exports.redeemGiftCard = functions.https.onCall(async (data, context) => {
74  if (!context.auth) throw new functions.https.HttpsError('unauthenticated', 'Login required');
75  const { code, amount } = data;
76  const db = admin.firestore();
77  const snap = await db.collection('gift_cards').where('code', '==', code).limit(1).get();
78  if (snap.empty) throw new functions.https.HttpsError('not-found', 'Invalid code');
79  const cardRef = snap.docs[0].ref;
80
81  return db.runTransaction(async (tx) => {
82    const card = await tx.get(cardRef);
83    const bal = card.data().currentBalance;
84    if (bal <= 0) throw new functions.https.HttpsError('failed-precondition', 'No balance');
85    const deduction = Math.min(bal, amount);
86    tx.update(cardRef, { currentBalance: admin.firestore.FieldValue.increment(-deduction) });
87    tx.create(db.collection('gift_card_transactions').doc(), {
88      cardId: card.id, type: 'redemption', amount: deduction,
89      timestamp: admin.firestore.FieldValue.serverTimestamp(),
90    });
91    return { deducted: deduction, remaining: bal - deduction };
92  });
93});