import nacl from "tweetnacl";
import base32 from "hi-base32";
import sha512 from "js-sha512";

const PUBLIC_KEY_LENGTH = nacl.sign.publicKeyLength;
const ALGORAND_ADDRESS_LENGTH = 58;
const ALGORAND_CHECKSUM_BYTE_LENGTH = 4;

export const encodeAddress = (address: Uint8Array): string => {
  const checksum = sha512.sha512_256
    .array(address)
    .slice(PUBLIC_KEY_LENGTH - ALGORAND_CHECKSUM_BYTE_LENGTH, PUBLIC_KEY_LENGTH);
  const addr = base32.encode(concatArrays(address, checksum));

  return addr.toString().slice(0, ALGORAND_ADDRESS_LENGTH);
};

function concatArrays(...arrs: ArrayLike<number>[]): Uint8Array {
  const size = arrs.reduce((sum, arr) => sum + arr.length, 0);
  const c = new Uint8Array(size);

  let offset = 0;
  for (let i = 0; i < arrs.length; i++) {
    c.set(arrs[i], offset);
    offset += arrs[i].length;
  }

  return c;
}