USDC Permit on Mumbai

permitUSDC.ts

import { getClient, type ReservoirWallet } from '@reservoir0x/reservoir-sdk';
import { GelatoRelay } from "@gelatonetwork/relay-sdk";
import { ConnectedWallet } from '@privy-io/react-auth';
import { ethers } from 'ethers';
import { getTaskStatus } from './poll';
import USDC_ABI from './usdcABI.json';
import {ethers} from 'ethers';

const GELATO_API_KEY = process.env.NEXT_PUBLIC_GELATO_API_KEY || "";

const CHAIN_ID = `0x${getClient().chains[0].id.toString(16)}`; // 0x13881
const USDC_CONTRACT_ADDRESS = process.env.NEXT_PUBLIC_USDC_CONTRACT_ADDRESS || ""; // 0x0FA8781a83E46826621b3BC094Ea2A0212e71B23
const SEAPORT_CONDUIT_CONTRACT_ADDRESS = process.env.NEXT_PUBLIC_SEAPORT_CONDUIT_CONTRACT_ADDRESS || ""; // 0x1E0049783F008A0085193E00003D00cd54003c71

const PERMIT_DOMAIN = {
  "name": "USD Coin (PoS)",
  "version": "1",
  "verifyingContract": USDC_CONTRACT_ADDRESS,
  "salt": ethers.utils.hexZeroPad(CHAIN_ID, 32)
}

const PERMIT_TYPES = {
  "Permit": [
    {
        "name": "owner",
        "type": "address"
    },
    {
        "name": "spender",
        "type": "address"
    },
    {
        "name": "value",
        "type": "uint256"
    },
    {
        "name": "nonce",
        "type": "uint256"
    },
    {
        "name": "deadline",
        "type": "uint256"
    }
  ]
}

const relay = new GelatoRelay();

export const permitUSDC = async (wallet: ConnectedWallet, price: string, expiration: number) => {
    // Switch to desired network
    const ethereumProvider = await wallet.getEthereumProvider();
    try {
      ethereumProvider.request({
        method: 'wallet_switchEthereumChain',
        params: [{chainId: CHAIN_ID}]
      })
    } catch (error) {
      throw new Error(`Failed to switch wallet to chainId ${CHAIN_ID} with error ${error}`);
    }

    const ethersProvider = await wallet.getEthersProvider();
    const signer = ethersProvider.getSigner();

    const usdc = new ethers.Contract(USDC_CONTRACT_ADDRESS, USDC_ABI, signer);

    // Construct values for USDC Permit
    const nonce = await usdc.nonces(wallet.address);
    const permitAmount = ethers.BigNumber.from(price);
    const values = {
      owner: wallet.address,
      spender: SEAPORT_CONDUIT_CONTRACT_ADDRESS,
      nonce: nonce,
      deadline: expiration,
      value: permitAmount
    }

    // Sign USDC permit
    const signature = await signer?._signTypedData(PERMIT_DOMAIN, PERMIT_TYPES, values);
    const {v, r, s} = ethers.utils.splitSignature(signature as string);

    // Relay USDC permit transaction
    try {
        const {data} = await usdc.populateTransaction.permit!(wallet.address, SEAPORT_CONDUIT_CONTRACT_ADDRESS, permitAmount, expiration, v, r, s);
        const request = {
            chainId: CHAIN_ID,
            target: USDC_CONTRACT_ADDRESS,
            data: data as string,
            user: wallet.address
        }
        const relayResponse = await relay.sponsoredCallERC2771(request, ethersProvider, GELATO_API_KEY)
        const txHash = await getTaskStatus(relayResponse.taskId);

        return txHash;
    } catch (error) {
        throw new Error(`Failed to permit USDC with Gelato with error ${error}`);
    }
}