.js

import pick from "@stdlib/random-sample";

export const drawWinnerAirdrop = (
  participants,
  hash,
  numberBigAmount,
  numberSmallAmount,
  bigAmount,
  smallAmount
) => {
  const seed = Number(`0x${hash.slice(-6)}`);
  const sum = participants.reduce((prev, e) => prev + Number(e.points), 0);
  const sample = pick.factory({
    replace: false,
    seed,
    size: Math.min(numberBigAmount + numberSmallAmount, participants.length),
  });

  const draw = sample(participants.map((e) => e.address),
  { probs: participants.map((e) => Number(e.points) / sum)});
  const winnersObj = Object.fromEntries(
    draw.map((e, i) => [e, i < numberBigAmount ? bigAmount : smallAmount])
  );

  return participants.map((e) => ({
    address: e.address,
    points: e.points,
    rewards: String(winnersObj[e.address] || 0),
  }));
};

export default drawWinnerAirdrop;