batch-transfers-example.js

'use strict'

/**
 * Batch Transfers Example
 *
 * This script demonstrates how to send multiple transfers in a single
 * UserOperation using the WDK EVM ERC-4337 wallet.
 *
 * IMPORTANT: Before running this script:
 * 1. Replace the seed phrase with your test wallet seed phrase
 * 2. Replace YOUR_CANDIDE_API_KEY with your Candide paymaster API key
 * 3. Make sure your Safe smart account has enough funds to cover:
 *    - The transfer amounts
 *    - The paymaster token (USDT) for gas fees
 * 4. Approve the paymaster contract to spend your USDT (see README)
 *
 * Run with: node examples/batch-transfers-example.js
 */

import { Interface } from 'ethers'
import WalletManagerEvmErc4337 from '../index.js'

// ============================================================================
// CONFIGURATION - Update these values for your setup
// ============================================================================

// Your BIP-39 seed phrase - DO NOT use in production or commit to git!
const SEED_PHRASE = 'your twelve word seed phrase goes here replace with actual words'

// ============================================================================
// CANDIDE CONFIGURATION FOR SEPOLIA TESTNET
// Get your API key from https://dashboard.candide.dev
// ============================================================================
const CONFIG = {
  chainId: 11155111, // Sepolia
  provider: 'https://ethereum-sepolia-rpc.publicnode.com', // Public RPC
  bundlerUrl: 'https://api.candide.dev/public/v3/11155111', // Public bundler (no API key needed)
  paymasterUrl: 'https://api.candide.dev/paymaster/v3/sepolia/YOUR_CANDIDE_API_KEY',
  paymasterAddress: '0x8b1f6cb5d062aa2ce8d581942bbb960420d875ba', // Candide ERC-20 Paymaster
  entryPointAddress: '0x0000000071727De22E5E9d8BAf0edAc6f37da032', // EntryPoint v0.7
  safeModulesVersion: '0.3.0',
  paymasterToken: {
    address: '0xd077A400968890Eacc75cdc901F0356c943e4fDb' // USDT on Sepolia
  }
}

// Example recipient addresses (use your own test addresses)
const RECIPIENTS = [
  '0x0000000000000000000000000000000000000001',
  '0x0000000000000000000000000000000000000002',
  '0x0000000000000000000000000000000000000003'
]

// ============================================================================
// BATCH TRANSFER EXAMPLES
// ============================================================================

/**
 * Example 1: Batch USDT Transfers
 *
 * Sends USDT to multiple recipients in a single UserOperation.
 * All transfers are executed atomically - either all succeed or all fail.
 */
async function batchUsdtTransfers (account) {
  console.log('\n--- Example 1: Batch USDT Transfers ---\n')

  const USDT_ADDRESS = '0xd077A400968890Eacc75cdc901F0356c943e4fDb'

  // ERC20 transfer function interface
  const erc20Interface = new Interface([
    'function transfer(address to, uint256 amount) returns (bool)'
  ])

  // Create an array of USDT transfer transactions
  const transactions = [
    {
      to: USDT_ADDRESS,
      value: 0n,
      data: erc20Interface.encodeFunctionData('transfer', [RECIPIENTS[0], 100000n]) // 0.1 USDT
    },
    {
      to: USDT_ADDRESS,
      value: 0n,
      data: erc20Interface.encodeFunctionData('transfer', [RECIPIENTS[1], 200000n]) // 0.2 USDT
    },
    {
      to: USDT_ADDRESS,
      value: 0n,
      data: erc20Interface.encodeFunctionData('transfer', [RECIPIENTS[2], 300000n]) // 0.3 USDT
    }
  ]

  console.log('Transactions to send:')
  console.log(`  1. Send 0.1 USDT to ${RECIPIENTS[0]}`)
  console.log(`  2. Send 0.2 USDT to ${RECIPIENTS[1]}`)
  console.log(`  3. Send 0.3 USDT to ${RECIPIENTS[2]}`)

  // Get fee estimate for the batch
  console.log('\nEstimating fees...')
  const quote = await account.quoteSendTransaction(transactions)
  console.log(`Estimated fee: ${Number(quote.fee) / 1e6} USDT`)

  // Send the batch transaction
  console.log('\nSending batch transaction...')
  const result = await account.sendTransaction(transactions)

  console.log('\nResult:')
  console.log(`  UserOperation hash: ${result.hash}`)
  console.log(`  Fee paid: ${Number(result.fee) / 1e6} USDT`)

  return result
}

/**
 * Example 2: Batch ERC20 Token Transfers
 *
 * Sends ERC20 tokens to multiple recipients in a single UserOperation.
 * Uses raw transaction data with encoded function calls.
 */
async function batchErc20Transfers (account, tokenAddress) {
  console.log('\n--- Example 2: Batch ERC20 Token Transfers ---\n')

  // ERC20 transfer function interface
  const erc20Interface = new Interface([
    'function transfer(address to, uint256 amount) returns (bool)'
  ])

  // Create transfer transactions
  const transactions = [
    {
      to: tokenAddress,
      value: 0n,
      data: erc20Interface.encodeFunctionData('transfer', [
        RECIPIENTS[0],
        1000000n // 1 token (assuming 6 decimals)
      ])
    },
    {
      to: tokenAddress,
      value: 0n,
      data: erc20Interface.encodeFunctionData('transfer', [
        RECIPIENTS[1],
        2000000n // 2 tokens
      ])
    },
    {
      to: tokenAddress,
      value: 0n,
      data: erc20Interface.encodeFunctionData('transfer', [
        RECIPIENTS[2],
        3000000n // 3 tokens
      ])
    }
  ]

  console.log(`Token contract: ${tokenAddress}`)
  console.log('Transfers to send:')
  console.log(`  1. 1 token to ${RECIPIENTS[0]}`)
  console.log(`  2. 2 tokens to ${RECIPIENTS[1]}`)
  console.log(`  3. 3 tokens to ${RECIPIENTS[2]}`)

  // Get fee estimate
  console.log('\nEstimating fees...')
  const quote = await account.quoteSendTransaction(transactions)
  console.log(`Estimated fee: ${Number(quote.fee) / 1e6} USDT`)

  // Send the batch
  console.log('\nSending batch transaction...')
  const result = await account.sendTransaction(transactions)

  console.log('\nResult:')
  console.log(`  UserOperation hash: ${result.hash}`)
  console.log(`  Fee paid: ${Number(result.fee) / 1e6} USDT`)

  return result
}

/**
 * Example 3: Mixed Batch (Native + ERC20 + Contract Calls)
 *
 * Demonstrates combining different transaction types in a single batch.
 */
async function mixedBatchTransactions (account, tokenAddress) {
  console.log('\n--- Example 3: Mixed Batch Transactions ---\n')

  const erc20Interface = new Interface([
    'function transfer(address to, uint256 amount) returns (bool)',
    'function approve(address spender, uint256 amount) returns (bool)'
  ])

  const transactions = [
    // 1. Send native ETH
    {
      to: RECIPIENTS[0],
      value: 1000000000000000n, // 0.001 ETH
      data: '0x'
    },
    // 2. Transfer ERC20 tokens
    {
      to: tokenAddress,
      value: 0n,
      data: erc20Interface.encodeFunctionData('transfer', [
        RECIPIENTS[1],
        1000000n
      ])
    },
    // 3. Approve a spender
    {
      to: tokenAddress,
      value: 0n,
      data: erc20Interface.encodeFunctionData('approve', [
        RECIPIENTS[2],
        5000000n // Approve 5 tokens
      ])
    }
  ]

  console.log('Mixed batch operations:')
  console.log(`  1. Send 0.001 ETH to ${RECIPIENTS[0]}`)
  console.log(`  2. Transfer 1 token to ${RECIPIENTS[1]}`)
  console.log(`  3. Approve 5 tokens for ${RECIPIENTS[2]}`)

  // Get fee estimate
  console.log('\nEstimating fees...')
  const quote = await account.quoteSendTransaction(transactions)
  console.log(`Estimated fee: ${Number(quote.fee) / 1e6} USDT`)

  // Send the batch
  console.log('\nSending batch transaction...')
  const result = await account.sendTransaction(transactions)

  console.log('\nResult:')
  console.log(`  UserOperation hash: ${result.hash}`)
  console.log(`  Fee paid: ${Number(result.fee) / 1e6} USDT`)

  return result
}

/**
 * Example 4: Fee Estimation Only (Dry Run)
 *
 * Shows how to estimate fees without actually sending the transaction.
 */
async function estimateBatchFees (account) {
  console.log('\n--- Example 4: Fee Estimation Only ---\n')

  // Various batch sizes to compare fees
  const batchSizes = [1, 3, 5, 10]

  for (const size of batchSizes) {
    const transactions = Array.from({ length: size }, (_, i) => ({
      to: `0x${(i + 1).toString(16).padStart(40, '0')}`, // Valid 20-byte addresses
      value: 1000000000000000n, // 0.001 ETH each
      data: '0x'
    }))

    const quote = await account.quoteSendTransaction(transactions)
    console.log(`Batch of ${size} transfers: fee = ${Number(quote.fee) / 1e6} USDT`)
  }

  console.log('\nNote: Batching is more gas-efficient than individual transactions!')
}

// ============================================================================
// MAIN EXECUTION
// ============================================================================

async function main () {
  console.log('='.repeat(60))
  console.log('WDK EVM ERC-4337 Batch Transfers Demo')
  console.log('='.repeat(60))

  // Validate configuration
  if (CONFIG.paymasterUrl.includes('YOUR_CANDIDE_API_KEY')) {
    console.error('\nError: Please update the CONFIG with your Candide API key')
    console.log('\nTo run this example, you need:')
    console.log('  1. A Candide API key from https://dashboard.candide.dev')
    console.log('  2. Your seed phrase')
    console.log('  3. USDT in your Safe smart account (for transfers + gas fees)')
    console.log('  4. Approve the paymaster to spend your USDT')
    process.exit(1)
  }

  if (SEED_PHRASE.includes('your twelve word')) {
    console.error('\nError: Please update SEED_PHRASE with your actual seed phrase')
    process.exit(1)
  }

  try {
    // Create wallet manager
    console.log('\nInitializing wallet...')
    const wallet = new WalletManagerEvmErc4337(SEED_PHRASE, CONFIG)

    // Get the first account
    const account = await wallet.getAccount(0)

    // Get and display the Safe account address
    const address = await account.getAddress()
    console.log(`Safe smart account address: ${address}`)

    // Check balances
    const balance = await account.getBalance()
    console.log(`Native token balance: ${Number(balance) / 1e18} ETH`)

    const usdtBalance = await account.getTokenBalance(CONFIG.paymasterToken.address)
    console.log(`USDT balance: ${Number(usdtBalance) / 1e6} USDT`)

    // Run examples (uncomment the one you want to test)

    // Example 1: Batch USDT transfers
    await batchUsdtTransfers(account)

    // Example 2: Batch any ERC20 transfers
    // await batchErc20Transfers(account, 'TOKEN_CONTRACT_ADDRESS')

    // Example 3: Mixed batch (ETH + tokens + approvals)
    // await mixedBatchTransactions(account, 'TOKEN_CONTRACT_ADDRESS')

    // Example 4: Fee estimation only (safe to run, no actual transfers)
    // await estimateBatchFees(account)

    // Clean up
    wallet.dispose()

    console.log('\n' + '='.repeat(60))
    console.log('Demo complete!')
    console.log('='.repeat(60))
  } catch (error) {
    console.error('\nError:', error.message)
    if (error.message.includes('AA50')) {
      console.log('\nHint: Make sure your Safe account has enough USDT to cover gas fees.')
    }
    if (error.message.includes('allowance')) {
      console.log('\nHint: You need to approve the paymaster to spend your USDT first.')
      console.log('Paymaster address:', CONFIG.paymasterAddress)
    }
    process.exit(1)
  }
}

main()