var caryears = -1;
var numberofrates =-1;

function setRatesOptions(_select, _years,empty_text)
{
  if (_years.value =='')
  {
     caryears = -1;
     return false;
  }
  var year = _years.value;

  _select.options.length = null;
  _select.options[0] = new Option(empty_text,"",false,false);

  var option_counter = 1;
  for (k=0; k < years2rates[year].length; k++)
  {
    _select.options[option_counter++] = new Option(' '+years2rates[year][k]+' ',k,false,false);

  }
  caryears = year;
}

function setParam(_select)
{
  if (_select.value == '')
      numberofrates = -1
  else
   numberofrates = _select.value;

}


function ShowRate(_value,_year,_rates)
{

  if (( _year.value < 0) || (! _year.value) || ( _rates.value < 0) || (! _rates.value) || ( _value.value < 5000 ))
  {
    alert ('Proszę wybrać wiek pojazdu i ilość rat\n wymagana minimalna kwota to 5000 zł');
    return false;
  }

	var oAmortizationTable=document.getElementById("amortizationtable");
		oAmortizationTable.style.visibility="visible";
		var sCR=String.fromCharCode(13);
		var sTab=String.fromCharCode(27);

		/* Calculate amortization and write table to text area **/
//		alert (_value.value);
//    alert (caryears);
//    alert (numberofrates);
//		alert (years2param[caryears][numberofrates]);
		var payment = (0 + _value.value) * (0 + years2param[_year.value][_rates.value]);
		oAmortizationTable.value = (Math.round(payment*100)/100) + " zł ";

}





	function getAmortization(a,n,p) {
		var i=0;
		var sATline="";
		var oAmortizationTable=document.getElementById("amortizationtable");
		oAmortizationTable.style.visibility="visible";
		var sCR=String.fromCharCode(13);
		var sTab=String.fromCharCode(27);

		/* Calculate amortization and write table to text area **/
		var payment = getPayment(a,n,p);
		oAmortizationTable.value = (Math.round(payment*100)/100) + " zł ";
/*		oAmortizationTable.value += "Miesi?c  Pozosta?o  Principal  odsetki  ??cznie   suma odsetek" + sCR;
		var balance=a;
		var interest = 0.0;
		var principal=0.0;
		var totalinterest=0.0;
		for (i=1;i<=n;i++) {
			interest = balance*p/1200;
			totalinterest += interest;
			principal = payment-interest;
			balance -= principal;
			sATline = i.toString()+getSpaces(7-i.toString().length);
			sATline += Math.round(balance*100)/100;
			sATline += getSpaces(18-sATline.length);
			sATline += (Math.round(principal*100)/100);
			sATline += getSpaces(29-sATline.length);
			sATline += (Math.round(interest*100)/100);
			sATline += getSpaces(39-sATline.length);
			sATline += (Math.round(i*payment*100)/100);
			sATline += getSpaces(50-sATline.length);
			sATline += (Math.round(totalinterest*100)/100) + sCR;
			oAmortizationTable.value += sATline;
		}
		*/
	}

	function getSpaces(n) {
		var i=0;
		var sSpaces="";
		for (i=0;i<n;i++) {sSpaces += " ";}
		return sSpaces;
	}

	function getPayment(a,n,p) {
		/* Calculates the monthly payment from annual percentage
		   rate, term of loan in months and loan amount. **/
		var acc=0;
		var base = 1 + p/1200;
		for (i=1;i<=n;i++)
			{ acc += Math.pow(base,-i); }
		return a/acc;
	}