import { Contract, JsonRpcProvider, MaxUint256, Wallet } from "ethers";

async function approveOrderFill() {
  const privateKey = process.env.SX_PRIVATE_KEY;
  const tokenAddress = process.env.TOKEN_ADDRESS;

  // get the following from https://api.sx.bet/metadata
  const tokenTransferProxyAddress = process.env.TOKEN_TRANSFER_PROXY_ADDRESS;
  const chainId = Number(process.env.CHAIN_ID); // Mainnet — use 79479957 for testnet

  const wallet = new Wallet(
    privateKey,
    new JsonRpcProvider(process.env.RPC_URL) // find this under the 'references' section
  );

  const tokenContract = new Contract(
    tokenAddress,
    [
      {
        inputs: [
          { internalType: "address", name: "usr", type: "address" },
          { internalType: "uint256", name: "wad", type: "uint256" },
        ],
        name: "approve",
        outputs: [{ internalType: "bool", name: "", type: "bool" }],
        stateMutability: "nonpayable",
        type: "function",
      },
      {
        inputs: [{ internalType: "address", name: "owner", type: "address" }],
        name: "nonces",
        outputs: [{ internalType: "uint256", name: "", type: "uint256" }],
        stateMutability: "view",
        type: "function",
      },
      {
        inputs: [],
        name: "name",
        outputs: [{ internalType: "string", name: "", type: "string" }],
        stateMutability: "view",
        type: "function",
      },
    ],
    wallet
  );

  const nonce = await tokenContract.nonces(wallet.address);
  const tokenName = await tokenContract.name();

  const domain = {
    name: tokenName,
    version: "1",
    chainId,
    verifyingContract: tokenAddress,
  };

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

  const deadline = Math.floor(Date.now() / 1000) + 7200; // 2 hours

  const value = {
    owner: wallet.address,
    spender: tokenTransferProxyAddress,
    value: MaxUint256,
    nonce,
    deadline,
  };

  const approveProxySignature = await wallet.signTypedData(domain, types, value);

  const apiPayload = {
    owner: wallet.address,
    spender: tokenTransferProxyAddress,
    tokenAddress,
    value: MaxUint256.toString(),
    deadline,
    signature: approveProxySignature,
  };

  const response = await fetch("https://api.sx.bet/orders/approve", { // Mainnet — use https://api.toronto.sx.bet for testnet
    method: "POST",
    body: JSON.stringify(apiPayload),
    headers: { "Content-Type": "application/json" },
  });
}

{
  "status": "success",
  "data": {
    "hash": "0x840763ae29b7a6adfa0e315afa47be30cdebd5b793d179dc07dc8fc4f0034965"
  }
}