Xahau Voucher state

state.mjs

import { getPubKey, xflHexToString } from "./statelib.mjs";

const main = async () => {
  console.log(getPubKey(process.argv[2]));
  const options = {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
    },
    body: JSON.stringify({
      method: "ledger_entry",
      params: [
        {
          hook_state: {
            account: "rvoucheredGC1mB4yd2CBjs7jGMRTLexe",
            namespace_id:
              "5B85492F93FF99C3D72A121F2BF28BC9858EE7209AC3DA5C1079B529F4A6CAF0",
            key: getPubKey(process.argv[2]),
          },
        },
      ],
    }),
  };

  const url = "https://xahau.network";
  const response = await fetch(url, options);
  const { result } = await response.json();
  console.log(
    JSON.stringify(
      { amount: Number(xflHexToString(result.node.HookStateData)) },
      null,
      "\t"
    )
  );
  if (result.error) return 0; // Voucher might have been claimed or it's invalid
  return { amount: Number(xflHexToString(result.node.HookStateData)) };
};
main();

statelib.mjs

import { derive } from "xrpl-accountlib";

export function getPubKey(privateKey) {
  const { keypair } = derive.privatekey(privateKey);
  if (typeof keypair.publicKey === "string") {
    const res = keypair.publicKey;
    return res.slice(2);
  }
}

export function xflHexToString(hex) {
  const buffer = Buffer.from(hexToBytes(hex));
  const integerValue = BigInt(buffer.readBigInt64LE());
  const stringValue = to_string(integerValue);
  return stringValue === "<zero>" ? "0" : stringValue;
}

const hexToBytes = (hexString) => {
  if (hexString.length % 2 !== 0) {
    throw new Error("Hex string length must be even");
  }

  const byteArray = [];
  for (let i = 0; i < hexString.length; i += 2) {
    byteArray.push(parseInt(hexString.substr(i, 2), 16));
  }

  return byteArray;
};

function get_exponent(xfl) {
  if (xfl < 0n) throw "Invalid XFL";
  if (xfl == 0n) return 0n;
  return ((xfl >> 54n) & 0xffn) - 97n;
}

function get_mantissa(xfl) {
  if (xfl < 0n) throw "Invalid XFL";
  if (xfl == 0n) return 0n;
  return xfl - ((xfl >> 54n) << 54n);
}

function is_negative(xfl) {
  if (xfl < 0n) throw "Invalid XFL";
  if (xfl == 0n) return false;
  return ((xfl >> 62n) & 1n) == 0n;
}

const to_string = (xfl) => {
  if (xfl < 0n) throw "Invalid XFL";
  if (xfl == 0n) return "<zero>";
  return `${is_negative(xfl) ? "-" : ""}${get_mantissa(xfl)}e${get_exponent(
    xfl
  )}`;
};