<?php

// IPAD

error_reporting(-1);

function calculateTotalPayments($creditSum, $payout, $percent, $servicePayment){
	
	$totalPayments = 0;
	
	for ($month = 1; $month < 20; $month++){
		$creditSum = ($creditSum * $percent) + $servicePayment;
		if ($creditSum < $payout) {
			$payout = $creditSum;
			$creditSum -= $payout;
		} else {
			$creditSum -= $payout;
		}

		$totalPayments += $payout;
		
		if ($creditSum == 0) {
			break;
		}
	}
	
	return $totalPayments;

}

$creditSum = 39999;
$payout = 5000;

$homoCreditTotal= calculateTotalPayments($creditSum, $payout, 1.04, 500);
$softbankTotal= calculateTotalPayments($creditSum, $payout, 1.03, 1000);;
$strawberryBankTotal=calculateTotalPayments($creditSum + 7777, $payout, 1.02, 0);;

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