leaseGenerator.sol

function createNewLease(
    uint8 numberOfMonths,
    uint16 monthlyAmountUsd,
    uint16 leaseDepositUsd,
    uint32 leasePaymentWindowSeconds,
    uint32 depositPaymentWindowSeconds,
    address payable tenantAddr
    ) public onlyLandlord {

    uint64 depositPaymentWindowEnd = uint64(now.add(depositPaymentWindowSeconds));

    tenantLease[tenantAddr] = Lease(
    numberOfMonths,
    0,
    monthlyAmountUsd,
    leaseDepositUsd,
    leasePaymentWindowSeconds,
    0,
    depositPaymentWindowEnd,
    false,
    false
    );

    emit leaseCreated(
    numberOfMonths,
    0,
    monthlyAmountUsd,
    leaseDepositUsd,
    leasePaymentWindowSeconds,
    false,
    false
    );
}

function payLeaseDeposit() public payable {
    Lease storage lease = tenantLease[msg.sender];
    require(!lease.leaseDepositPaid, "Lease deposit is already paid.");
    require(lease.depositPaymentWindowEnd >= now, "Lease deposit payment must fit into payment window");

    tenantAddress = msg.sender;
    tenantPayment = msg.value;
    workingState = State.payingLeaseDeposit;
    fetchUsdRate();
}

function _payLeaseDeposit() internal {
    workingState = State.idle;
    Lease storage lease = tenantLease[tenantAddress];
    uint amountSentUsd = tenantPayment.mul(ETHUSD).div(1e18);

    require(
        amountSentUsd >= lease.leaseDepositUsd - 5 &&
        amountSentUsd <= lease.leaseDepositUsd + 5,
        "Deposit payment must equal to the deposit amount with a maximum offset of $5");

    lease.leaseDepositPaid = true;
    lease.depositPaymentWindowEnd = 0;
    lease.leasePaymentWindowEnd = uint64(now + lease.leasePaymentWindowSeconds);

    emit leaseDepositPaid(
        tenantAddress,
        amountSentUsd
    );
}