Sweep deposits

app.post('/webhooks/dfns', express.json(), async (req, res) => {
  const event = req.body

  // Verify the event comes from DFNS. See webhook signature verification
  if (!verifyDfnsWebhookSignature(event, req.headers['x-dfns-webhook-signature'])) {
    return res.status(401).send('Invalid signature')
  }

  // Always respond quickly. Process async
  res.status(200).send('OK')

  if (event.kind !== 'wallet.blockchainevent.detected') return

  const { walletId, blockchainEvent } = event.data

  // Only process incoming transfers
  if (blockchainEvent.direction !== 'In') return

  await enqueueSweep({
    walletId,
    kind: blockchainEvent.kind,
    amount: blockchainEvent.value,
    contract: blockchainEvent.contract, // present for token transfers
    txHash: blockchainEvent.txHash,
  })
})

const TREASURY_WALLET_ID = 'wa-treasury-xxx'

// Get the treasury wallet address
const treasury = await dfns.wallets.getWallet({
  walletId: TREASURY_WALLET_ID,
})

async function executeSweep(deposit: {
  walletId: string
  kind: string
  amount: string
  contract?: string
  txHash: string
}) {
  // Map blockchain event kind to transfer kind
  const transferBody = buildTransferBody(deposit, treasury.address)

  const transfer = await dfns.wallets.createTransfer({
    walletId: deposit.walletId,
    body: {
      ...transferBody,
      externalId: `sweep-${deposit.txHash}`, // idempotency
    },
  })

  console.log(`Sweep initiated: ${transfer.id} (${transfer.status})`)
}

function buildTransferBody(
  deposit: { kind: string; amount: string; contract?: string },
  treasuryAddress: string
) {
  switch (deposit.kind) {
    case 'NativeTransfer':
      return {
        kind: 'Native' as const,
        to: treasuryAddress,
        amount: deposit.amount,
      }
    case 'Erc20Transfer':
      return {
        kind: 'Erc20' as const,
        to: treasuryAddress,
        amount: deposit.amount,
        contract: deposit.contract!,
      }
    case 'SplTransfer':
      return {
        kind: 'Spl' as const,
        to: treasuryAddress,
        amount: deposit.amount,
        contract: deposit.contract!,
      }
    // Handle other transfer kinds as needed
    default:
      throw new Error(`Unsupported transfer kind: ${deposit.kind}`)
  }
}