Monetize swaps with partner fees

import { createPublicClient, createWalletClient, http, parseAbi } from "viem";
import { Address, privateKeyToAccount } from "viem/accounts";
import { mainnet } from "viem/chains";

// Delta address on Ethereum mainnet
const DELTA_ADDRESS = "0x0000000000bbf5c5fd284e657f01bd000933c96d";

const feeClaimerModuleAbi = parseAbi([
  "function getCollectedFees(address partner, address token) view returns (uint256)",
  "function withdrawAllFees(address token, address recipient) returns (uint256 amount)",
]);

const account = privateKeyToAccount(process.env.PRIVATE_KEY);

const publicClient = createPublicClient({
  chain: mainnet,
  transport: http(),
});

const walletClient = createWalletClient({
  account,
  chain: mainnet,
  transport: http(),
});

async function withdrawAllFees(
  tokenAddress: Address,
  recipientAddress: Address
) {
  const collectedFees = await publicClient.readContract({
    address: DELTA_ADDRESS,
    abi: feeClaimerModuleAbi,
    functionName: "getCollectedFees",
    args: [account.address, tokenAddress],
  });

  console.log(
    `Collected fees for token ${tokenAddress}:`,
    collectedFees.toString()
  );

  if (collectedFees === 0n) {
    console.log("No fees to withdraw for this token.");
    return;
  }

  // Simulate first to catch reverts
  const { request } = await publicClient.simulateContract({
    account,
    address: DELTA_ADDRESS,
    abi: feeClaimerModuleAbi,
    functionName: "withdrawAllFees",
    args: [tokenAddress, recipientAddress],
  });

  const hash = await walletClient.writeContract(request);
  console.log("Transaction sent:", hash);

  const receipt = await publicClient.waitForTransactionReceipt({ hash });
  console.log("Withdrawal confirmed in block:", receipt.blockNumber);

  return receipt;
}

// Withdraw all accrued USDC fees to the caller's address
await withdrawAllFees(
  "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48", // USDC
  account.address
);

const PARTNER_ADDRESS = "0x..."; // your partnerAddress
const CHAIN_ID = 1;

const parameters = JSON.stringify([
  {
    type: "category",
    value: PARTNER_ADDRESS,
    target: ["variable", ["template-tag", "partner_address"]],
  },
  {
    type: "category",
    value: CHAIN_ID,
    target: ["variable", ["template-tag", "chain_id"]],
  },
]);

const res = await fetch(
  `https://proxy.paraswap.io/fees/delta?parameters=${encodeURIComponent(
    parameters
  )}`
);
const { data } = await res.json();

// Each row is [chain_id, fee_token, total_amount]
for (const [, token, total] of data.rows) {
  console.log(`${token}: ${total}`);
}