@ledgerhq/coin-algorand/src/getFeesForTransaction.ts

Ledger Algorand Coin integration

import { BigNumber } from "bignumber.js";
import algorandAPI from "./api";
import { buildTransactionPayload, encodeToSign } from "./buildTransaction";
import type { AlgorandAccount, Transaction } from "./types";

// This is only true for a single signature. If we ever support different type of signatures
// (e.g multi signatures), we will have to add the correct corresponding number of bytes.
const SINGLE_SIGNATURE_SIZE = 71;

export const getEstimatedFees = async (
  account: AlgorandAccount,
  transaction: Transaction,
): Promise<BigNumber> => {
  const params = await algorandAPI.getTransactionParams();

  let suggestedFees = 0;
  if (params.fee) {
    const payload = await buildTransactionPayload(account, transaction);
    const encoded = encodeToSign(payload);
    suggestedFees = params.fee * (Buffer.from(encoded, "hex").length + SINGLE_SIGNATURE_SIZE);
  }
  return new BigNumber(Math.max(suggestedFees, params.minFee));
};