import type { TokenAmount } from "@saberhq/token-utils";
import { zip } from "lodash-es";

import type { ClaimableAmounts, GetAllClaimableAmounts } from "./types";

// number of ms in one year
const ONE_YEAR_MS = 365 * 86_400 * 1_000;

/**
 * Rewards per second
 */
export interface RewardRates {
  timeT0Ms: number;
  amountsT0: ClaimableAmounts;
  pools: (number | null)[];
  total: number;
}

/**
 * Calculate the rewards per second of all pools/total
 * @returns
 */
export const calculateRewardRates = (
  getAllClaimableAmounts: GetAllClaimableAmounts,
  msBetweenCheckpoints: number = ONE_YEAR_MS
): RewardRates | null => {
  const timeT0Ms = Date.now();
  const amountsT0 = getAllClaimableAmounts();
  const amountsT1 = getAllClaimableAmounts(msBetweenCheckpoints);

  if (!amountsT0 || !amountsT1) {
    return null;
  }

  return {
    timeT0Ms,
    amountsT0,
    pools: zip(amountsT0.allClaimable, amountsT1.allClaimable).map(
      ([amt0, amt1]) => {
        if (!amt0 || !amt1) {
          return null;
        }
        return calculateRewardsPerSecond(amt0, amt1, msBetweenCheckpoints);
      }
    ),
    total:
      amountsT0.sum && amountsT1.sum
        ? calculateRewardsPerSecond(
            amountsT0.sum,
            amountsT1.sum,
            msBetweenCheckpoints
          )
        : 0,
  };
};

const calculateRewardsPerSecond = (
  t0: TokenAmount,
  t1: TokenAmount,
  msBetweenCheckpoints: number
): number => {
  const t0Float = parseFloat(t0.toExact());
  const t1Float = parseFloat(t1.toExact());
  return ((t1Float - t0Float) / msBetweenCheckpoints) * 1_000;
};