Calculate Extra Farm Reward APY

import { createSolanaRpc, address } from '@solana/kit';
import { FarmState, calculateCurrentRewardPerToken } from '@kamino-finance/farms-sdk';
import { KaminoMarket, PROGRAM_ID, lamportsToNumberDecimal } from '@kamino-finance/klend-sdk';
import Decimal from 'decimal.js';

type ExtraFarm = { market: string; farm: string; collMint: string; debtMint: string };
type Resources = { 'mainnet-beta': { extraFarms: ExtraFarm[] } };

const rpc = createSolanaRpc('https://api.mainnet-beta.solana.com');
const mainMarketAddress = address('7u3HeHxYDLhnCoErrtycNokbQYbWGzLs6JSDqGAv5PfF');

// Load market and get CASH and SOL mints from reserves
const market = await KaminoMarket.load(rpc, mainMarketAddress, 400, PROGRAM_ID);

let cashReserve, solReserve;
for (const reserve of market!.reserves.values()) {
  if (reserve.stats.symbol === 'CASH') cashReserve = reserve;
  if (reserve.stats.symbol === 'SOL') solReserve = reserve;
}

if (!cashReserve || !solReserve) {
  throw new Error('CASH or SOL reserve not found');
}

const cashMint = cashReserve.getLiquidityMint().toString();
const solMint = solReserve.getLiquidityMint().toString();

// Get extraFarms from CDN API and filter by SOL/CASH pair
const cdnRes = await fetch('https://cdn.kamino.finance/resources.json');
const allResources = (await cdnRes.json()) as Resources;

const kaminoResources = allResources['mainnet-beta'];
const extraFarmsForMarket = kaminoResources.extraFarms.filter((f) => f.market === mainMarketAddress.toString());

// Filter by collateral (SOL) and debt (CASH) mints
const solCashFarms = extraFarmsForMarket.filter((f) => f.collMint === solMint && f.debtMint === cashMint);

// Fetch all farm states in batch
const farmAddresses = solCashFarms.map((f) => address(f.farm));
const farmStates = await FarmState.fetchMultiple(rpc, farmAddresses);

const farms = solCashFarms.flatMap((extraFarm, index) => {
  const farmState = farmStates[index];
  return farmState ? [{ farm: extraFarm.farm, farmState }] : [];
});

for (const { farm, farmState } of farms) {
  const totalStaked = lamportsToNumberDecimal(
    farmState.totalStakedAmount.toString(),
    farmState.token.decimals.toNumber() || 6
  );

  const cashReward = farmState.rewardInfos.find(
    (r) => r.token.mint.toString() === cashMint && r.rewardsAvailable.gtn(0)
  );

  if (cashReward && !totalStaked.isZero()) {
    const currentTime = new Decimal(Date.now() / 1000);

    // Calculate APY from farm rewards
    const rewardPerTokenPerSecond = calculateCurrentRewardPerToken(cashReward, currentTime); // returns the raw value
    const divisor = new Decimal(10)
      .pow(cashReward.rewardsPerSecondDecimals.toString())
      .mul(new Decimal(10).pow(cashReward.token.decimals.toString()));
    const adjustedRewardPerToken = new Decimal(rewardPerTokenPerSecond).div(divisor);
    const dailyRewards = adjustedRewardPerToken.mul(86400);
    const apy = Decimal.pow(dailyRewards.div(totalStaked).plus(1), 365).minus(1);

    console.log(`ExtraFarm: ${farm}`);
    console.log(`  CASH APY: ${(apy.toNumber() * 100).toFixed(2)}%\n`);
  }
}