private void CalculateOfflineRewards()
    {
        int allSecondsPassed = minutesPassed * 60 + PlayerPrefs.GetInt("rewardSecondsAlreadyPassed");

        minutesPassed += Mathf.FloorToInt(PlayerPrefs.GetInt("rewardSecondsAlreadyPassed") / 60);

        if (minutesPassed >= RewardIntervalMinute)
        {
            inGameManager.ChangeHeartAmount(Mathf.FloorToInt(minutesPassed / RewardIntervalMinute));
            Debug.Log("hearts to add to player: " + Mathf.FloorToInt(minutesPassed / RewardIntervalMinute));
        }
        else
        {
            Debug.Log("Not enough time passed.");
        }

        if (PlayerPrefs.GetInt("ActiveHearts") < inGameManager.GetMaxHeart())
        {
            StartCoroutine("RewardTimer", allSecondsPassed % (RewardIntervalMinute * 60));
        }
    }