test.ts

import { BalancerSDK, SwapType, Network, BatchSwapStep, EncodeBatchSwapInput, SwapTypes, Swaps } from '@balancer-labs/sdk';
import { ethers } from 'ethers';

const PRIVATE_KEY = '';
const INFURA_API_KEY = '';

async function executeFlashSwap(path: string[]) {
  const balancer = new BalancerSDK({
    network: Network.MAINNET,
    rpcUrl: `https://mainnet.infura.io/v3/${INFURA_API_KEY}`,
  });

  const provider = new ethers.providers.InfuraProvider(Network.MAINNET, INFURA_API_KEY);
  const wallet = new ethers.Wallet(PRIVATE_KEY, provider);

  const swaps: BatchSwapStep[] = [];
  const assets: string[] = [];

  for (let i = 0; i < path.length - 1; i++) {
    const tokenA = path[i];
    const tokenB = path[i + 1];

    const poolId = await findPoolId(tokenA, tokenB, balancer);

    if (!poolId) {
      throw new Error(`Pool not found for tokens ${tokenA} and ${tokenB}`);
    }

    const swapStep: BatchSwapStep = {
      poolId,
      assetInIndex: i === 0 ? i : i - 1,
      assetOutIndex: i === 0 ? i + 1 : i,
      amount: '0', // Replace with the appropriate amount for each swap step
      userData: '0x',
    };

    swaps.push(swapStep);
    assets.push(tokenA);
  }

  const funds = {
    sender: wallet.address,
    fromInternalBalance: false,
    recipient: wallet.address,
    toInternalBalance: false,
  };

  const limits = ['0'];
  const deadline = '999999999999999999';

  const encodedBatchSwapData = Swaps.encodeBatchSwap({
    kind: SwapType.SwapExactIn,
    swaps,
    assets,
    funds,
    limits,
    deadline,
  } );

  const tx = await wallet.sendTransaction({
    data: encodedBatchSwapData,
    to: 'balancerVault', // Replace with the appropriate Balancer vault address
    value: '0',
  });

  await tx.wait();
}

async function findPoolId(tokenA: string, tokenB: string, balancer: BalancerSDK): Promise<string | undefined> {
  const { pools } = balancer.data;
  const result = await pools.all();
  const filteredPools = result.filter(pool => parseFloat(pool.totalLiquidity) > 100000);

  for (const pool of filteredPools) {
    const tokens = pool.tokens.map((token: any) => token.address);

    if (tokens.includes(tokenA) && tokens.includes(tokenB)) {
      return pool.id;
    }
  }

  return undefined;
}