Subscription billing

import { useInvisibleWallet } from 'invisible-wallet-sdk'
import { hash as stellarHash, Networks } from '@stellar/stellar-sdk'
 
export default function SubscriptionBilling() {
  const { address, signAuthEntry } = useInvisibleWallet({
    factoryAddress: 'FACTORY_CONTRACT_ADDRESS',
    rpcUrl: 'https://soroban-testnet.stellar.org',
    networkPassphrase: Networks.TESTNET,
  })
 
  async function authorizeMonthlySubscription() {
    if (!address) {
      throw new Error('Register and deploy your wallet first.')
    }
 
    const billingRequest = {
      flow: 'subscription',
      planId: 'pro-monthly',
      amount: '10.00',
      currency: 'USD',
      recipient: 'GDT6...MERCHANT_ADDRESS',
      schedule: '30 days',
      wallet: address,
      timestamp: new Date().toISOString(),
    }
 
    const signaturePayload = stellarHash(
      new TextEncoder().encode(JSON.stringify(billingRequest)),
    )
 
    const authSignature = await signAuthEntry(signaturePayload)
 
    if (!authSignature) {
      throw new Error('Passkey authorization was cancelled.')
    }
 
    console.log('Passkey-approved billing auth:', authSignature)
 
    return authSignature
  }
 
  return (
    <button onClick={authorizeMonthlySubscription}>
      Authorize monthly subscription
    </button>
  )
}