<?php

error_reporting(-1);

function getBalanceInFuture($deposit, $payout, $percent, $contribution, $commission) {
	
	$paymentTotal = 0;
	
	$deposit = $deposit + $contribution;
	
	for ($month = 1; $month <= 70; $month++) {
		$deposit = ($deposit * $percent) + $commission;
		
		if($deposit >= $payout) {
			$deposit -= $payout;
			$paymentTotal +=  $payout;
			//echo "{month} месяц спустя, отстаток: {$deposit}, выплачено всего: {$paymentTotal}";
		} elseif ($deposit < $payout) {
			$paymentTotal += $deposit;
			$deposit -= $deposit;
			break;
		}
	}
	
	return $paymentTotal;
}

$creaditSum = 39999;
$payout = 5000;
$homoCreditTotal = getBalanceInFuture($creaditSum, $payout, 1.04, 0, 500);
$softbankTotal = getBalanceInFuture($creaditSum, $payout, 1.03, 0, 1000);
$strawberryBankTotal = getBalanceInFuture($creaditSum, $payout, 1.02, 7777, 0);

echo "homoCredit: {$homoCreditTotal} руб.\n";
echo "softbank: {$softbankTotal} руб.\n";
echo "strawberryBank: {$strawberryBankTotal} руб.\n";