Bitcoin Mining

'use strict';

function bitcoinMining(arr) {
  let bitcoin = 11949.16;
  let gold = 67.51;
  let bitcoinValueInGold = bitcoin / gold;
  let bitcoinBought = false;
  let bitcoinsMined = 0;
  let firstBitcoinDay;


  let i = 0;
  let day = 0;
  let minedTotal = 0;

  while (i < arr.length) {
    let minedToday = arr[i];
    day++;

    if (day === 3) {
      minedToday -= minedToday * 0.3;
      day = 0;
    }

    minedTotal += minedToday;

    //Can we afford Bitcoin
    if (minedTotal >= bitcoinValueInGold) {
      let bitcoins = Math.floor(minedTotal / bitcoinValueInGold);
      minedTotal -= bitcoinValueInGold * bitcoins;
      bitcoinsMined += bitcoins;
      bitcoinBought = true;

      !firstBitcoinDay ? firstBitcoinDay = day : null;
    }


    i++;
  }

  let moneyLeft = minedTotal * gold;

  //Output
  console.log(`Bought bitcoins: ${bitcoinsMined}`);
  bitcoinBought ? console.log(`Day of the first purchased bitcoin: ${firstBitcoinDay}`) : null;
  console.log(`Left money: ${moneyLeft.toFixed(2)} lv.`);
}

bitcoinMining([3124.15, 504.212, 2511.124, 333]);