Execute a Swidge with Butter Network

npm install @tetherto/wdk-wallet-evm@1.0.0-beta.17 viem@2.43.1

import ButterSwidgeProtocol, {
  ButterPartialExecutionError,
  formatTokenAmount,
  parseTokenAmount,
  toEvmPublicClient,
} from '@butternetwork/wdk-protocol-swidge-butter'
import { WalletAccountEvm } from '@tetherto/wdk-wallet-evm'
import { createPublicClient, http } from 'viem'
import { mainnet } from 'viem/chains'
import { createInterface } from 'node:readline/promises'
import { stdin, stdout } from 'node:process'
import { appendFile, writeFile } from 'node:fs/promises'
import { randomUUID } from 'node:crypto'

function requireEnv(name) {
  const value = process.env[name]?.trim()
  if (!value) throw new Error(`Set ${name}`)
  return value
}

function feeLimit(name) {
  const value = requireEnv(name)
  if (!/^\d+$/.test(value) || !Number.isSafeInteger(Number(value))) {
    throw new Error(`${name} must be a nonnegative safe integer`)
  }
  return Number(value)
}

const rpcUrl = requireEnv('RPC_URL')
try {
  if (new URL(rpcUrl).protocol !== 'https:') throw new Error()
} catch {
  throw new Error('Set a valid HTTPS RPC URL')
}
const privateKey = requireEnv('PRIVATE_KEY')
if (!/^0x[0-9a-fA-F]{64}$/.test(privateKey)) {
  throw new Error('PRIVATE_KEY must be a 32-byte 0x-prefixed hex value')
}
const entrance = requireEnv('BUTTER_ENTRANCE')
const limits = Object.freeze({
  maxNetworkFeeBps: feeLimit('MAX_NETWORK_FEE_BPS'),
  maxProtocolFeeBps: feeLimit('MAX_PROTOCOL_FEE_BPS'),
})
const publicClient = createPublicClient({ chain: mainnet, transport: http(rpcUrl) })
const chainId = await publicClient.getChainId().catch(() => {
  throw new Error('RPC chain check failed; verify endpoint access without logging credentials')
})
if (chainId !== 1) throw new Error('RPC must use Ethereum chain 1')

let account
try {
  account = WalletAccountEvm.fromPrivateKey(privateKey, { provider: rpcUrl, chainId: 1 })
} catch {
  throw new Error('Could not initialize the EVM account; check the private key and provider')
}
const protocol = new ButterSwidgeProtocol(account, {
  sourceChainId: '1',
  entrance,
  ...limits,
  evm: { publicClient: toEvmPublicClient(publicClient) },
})

const ETHEREUM_USDt = '0xdAC17F958D2ee523a2206206994597C13D831ec7'
const USDt_DECIMALS = 6
const json = value => JSON.stringify(value, (_key, item) => (
  typeof item === 'bigint' ? item.toString() : item
), 2)

async function confirmQuote(intent) {
  const quote = await protocol.quoteSwidge(intent)
  console.log(json({
    sourceChain: '1', intent, limits,
    estimatedUSDt: formatTokenAmount(quote.toTokenAmount, USDt_DECIMALS),
    minimumUSDt: formatTokenAmount(quote.toTokenAmountMin, USDt_DECIMALS),
    expiryUnixSeconds: quote.expiry,
    destinationGuarantees: quote.destinationGuarantees,
    fees: quote.fees.map(({ type, amount, token, chain, included }) => ({
      type, amountBaseUnits: amount, token, chain, included,
    })),
  }))
  if (!stdin.isTTY || !stdout.isTTY) throw new Error('Interactive confirmation is required')
  const prompt = createInterface({ input: stdin, output: stdout })
  try {
    if (await prompt.question('Type EXECUTE to submit this quote: ') !== 'EXECUTE') {
      throw new Error('Execution was not confirmed')
    }
  } finally {
    prompt.close()
  }
  return quote
}

const recordPath = `butter-${randomUUID()}.jsonl`
async function recordOperation(record) {
  const line = json(record).replaceAll('\n', '') + '\n'
  try {
    await appendFile(recordPath, line, { encoding: 'utf8', flush: true })
  } catch {
    console.error('Operation record write failed. Retain these details:', line)
    throw new Error('Inspect the wallet and preserve operation details before retrying')
  }
}

try {
  const intent = Object.freeze({
    fromToken: 'native',
    toToken: ETHEREUM_USDt,
    fromTokenAmount: parseTokenAmount('0.001', 18),
    toChain: '1',
    recipient: await account.getAddress(),
    slippage: 0.01,
    maxNativeFee: 0n,
  })
  await writeFile(recordPath, '', { flag: 'wx', mode: 0o600 })
  await recordOperation({ state: 'created', fromChain: '1', toChain: '1', intent })
  console.log('Operation record:', recordPath)
  const quote = await confirmQuote(intent)
  try {
    const result = await protocol.swidge({ ...intent, routeHash: quote.routeHash })
    await recordOperation({
      state: 'submitted', sourceHash: result.id, fromChain: '1', toChain: '1',
      transactions: result.transactions,
    })
    console.log('Source transaction:', result.id)
  } catch (error) {
    if (error instanceof ButterPartialExecutionError) {
      await recordOperation({
        state: 'partial', fromChain: '1', toChain: '1',
        transactions: error.transactions, failedType: error.failedType,
      })
    }
    throw new Error('Execution did not finish. Inspect the record and wallet before retrying')
  }
} catch {
  console.error('Operation stopped. Inspect the operation record and wallet before retrying.')
  process.exitCode = 1
} finally {
  account.dispose()
}

node execute-butter.mjs