function MortageCalculator() {
	
}

MortageCalculator.calculate = function() {
	
	if($("#own_resources").val().length == 0) {
		$("#own_resources").val(0);
	}
	
	if ($("#price").val() == 0 || $("#price").val().length == 0) {
        alert ("Cena nehnuteľnosti nemôže byť 0!");
        $("#price").focus();
    } else if ($("#interest_rate").val() == 0 || $("#interest_rate").val().length == 0) {
        alert ("Úroková sadzba nemôže byť 0!");
        $("#interest_rate").focus();
    } else if ($("#term").val() == 0 || $("#term").val().length == 0) {
        alert ("Trvanie hypotéky nemôže byť 0!");
        $("#term").focus();
    } else {
    	MortageCalculator.calculatePayment();
    }
        
};


MortageCalculator.calculatePayment = function() {
    /*princ = form.price.value - form.dp.value;
    intRate = (form.ir.value/100) / 12;
    months = form.term.value * 12;
    form.pmt.value = Math.floor((princ*intRate)/(1-Math.pow(1+intRate,(-1*months)))*100)/100;
	form.principle.value = princ;
	form.payments.value = months;*/
	
	var principle = $("#price").val() - $("#own_resources").val();
	var interestRate = ($("#interest_rate").val() / 100) / 12;
	var months = $("#term").val() * 12;
	
	
	var paymentPerMonth = Math.floor((principle * interestRate) / (1 - Math.pow(1 + interestRate, (-months))) * 100) / 100;
	
	$("#principle").val(principle);
	$("#months").val(months);
	$("#payment_per_month").val(paymentPerMonth);
	
};