function round(value,precision)
{
	var exp = Math.pow(10,precision);
	
	return Math.round(value*exp)/exp;
}

var activeForm = 0;

function initialize()
{
	document.chooseForm0.loanAmount.value = 5000;
	document.chooseForm0.loanInterest.value=8;
	document.chooseForm0.loanComissionType.value=1;
	document.chooseForm0.loanComissionValue.value=5;
	document.chooseForm0.loanComissionValueType.value=1;
	document.chooseForm0.loanTermNumber.value=12;
	document.chooseForm0.loanTermType.value=30;
	document.chooseForm0.loanInstallmentType.value=1;

	recalculate(document.chooseForm0.loanAmount,document.chooseForm0);
}

function recalculate(field,form)
{		
	if(field.type=="text")
	{
		if(field.value.indexOf(',')>0)
			field.value = field.value.replace(',','.');

		var numberRegExp = new RegExp("^[0-9\.,]*$");		
		if(!numberRegExp.test(field.value))
			field.value = field.value.replace(/[^0-9\.,]*/ig,'');	
	
		//check for double decimal separator
		var firstSep = field.value.indexOf(".");
		var secondSep = firstSep>0?field.value.indexOf(".",firstSep+1):-1;
		if(firstSep>0 && secondSep>firstSep)
		{
			field.value = field.value.substring(0,secondSep);
		}
	
		if(field.value[field.value.length-1]=='.')
			return;
	}

	if(!form.loanAmount.value) return;
	var amount = parseFloat(form.loanAmount.value);
	var creditAmount = amount;
	var additionalCost = 0;

	var comission = 0;
	if(form.loanComissionType.value==0)
	{
		form.loanComissionValue.disabled=true;
		form.loanComissionValue.value=0;
		form.loanComissionValueType.disabled=true;
	}else
	{
		form.loanComissionValue.disabled=false;
		form.loanComissionValueType.disabled=false;
		
		if(form.loanComissionValueType.value==1)
			comission = round(parseFloat(form.loanComissionValue.value)/100*amount,2);
		else 
			comission = round(parseFloat(form.loanComissionValue.value),2);
		
		switch(form.loanComissionType.value) 
		{
			case "1"://dolicz
				creditAmount += comission;
				additionalCost += comission;
				break;
			case "2"://odlicz
				amount -= comission;			
				additionalCost += comission;
				break;
			case "3"://oddzielnie
				additionalCost += comission;
				break;
			default:
				break;
		}
	}
	
	if(!form.loanTermNumber.value) return;
	var loanTerm = form.loanTermNumber.value * form.loanTermType.value;
	var loanInstallmentTerm = form.loanTermType.value;
	if(loanInstallmentTerm>30) loanInstallmentTerm = 30;//raty co najwyżej miesięczne
	
	var installmentCount = loanTerm/loanInstallmentTerm;//zakładamy tylko miesiące
	if(!form.loanInterest.value) return;
	var loanInterest = parseFloat(form.loanInterest.value)/100;

	var paymentAmounts = new Array();
	var paymentTerms = new Array();

	form.resultWithdraw.value = amount.toMoney(2,'.',' ');
	form.resultComission.value = comission.toMoney(2,'.',' ');

	if(form.loanInstallmentType.value==1)
	{	
		var q = 1 + loanInterest/(360/loanInstallmentTerm);
		var installment = round(creditAmount * Math.pow(q,installmentCount) * ((q-1)/(Math.pow(q,installmentCount)-1)),2);
	
		form.resultInstallmentFirst.value = installment.toMoney(2,'.',' ');
		form.resultInstallmentLast.value = installment.toMoney(2,'.',' ');
		var interestsTotal = installment*installmentCount-creditAmount;
		form.resultInstallmentTotal.value = (interestsTotal).toMoney(2,'.',' ');
		form.resultTotalCost.value = (interestsTotal+additionalCost).toMoney(2,'.',' ');
		
		for(var i=0;i<installmentCount;i++)
		{
			paymentAmounts[i] = installment;
			paymentTerms[i] = (i+1)*loanInstallmentTerm;
		}
	}else if (form.loanInstallmentType.value==2)
	{
		var interestsTotal = 0;	
		var installmentDebt = round(creditAmount/installmentCount,2);
		for(var installmentNumber = 1; installmentNumber < installmentCount; installmentNumber++)
		{
			var installmentInterests = round((creditAmount-(installmentNumber-1)*installmentDebt) * loanInterest/(360/loanInstallmentTerm),2);
			interestsTotal += installmentInterests;
			if(installmentNumber==1)
				form.resultInstallmentFirst.value = (installmentDebt + installmentInterests).toMoney(2,'.',' ');

			paymentAmounts[installmentNumber-1] = installmentDebt+installmentInterests;
			paymentTerms[installmentNumber-1] = installmentNumber*loanInstallmentTerm;			
		}
		var installmentInterests = round((creditAmount-(installmentCount-1)*installmentDebt) * loanInterest/(360/loanInstallmentTerm),2);	
		interestsTotal += installmentInterests;
		
		paymentAmounts[paymentAmounts.length] = installmentDebt+installmentInterests;
		paymentTerms[paymentTerms.length] = installmentCount*loanInstallmentTerm;
		
		form.resultInstallmentLast.value = ((creditAmount-(installmentCount-1)*installmentDebt) + installmentInterests).toMoney(2,'.',' ');
		form.resultInstallmentTotal.value = interestsTotal.toMoney(2,'.',' ');
		
		form.resultTotalCost.value = (interestsTotal+additionalCost).toMoney(2,'.',' ');				
	}else 
	{		
		installmentInterests = round(creditAmount * loanInterest/(360/loanTerm),2);

		paymentAmounts[0] = creditAmount+installmentInterests;
		paymentTerms[0] = loanTerm;
									
		form.resultInstallmentFirst.value = paymentAmounts[0].toMoney(2,'.',' ');
		form.resultInstallmentLast.value = "-";
		form.resultInstallmentTotal.value = installmentInterests.toMoney(2,'.',' ');
		
		form.resultTotalCost.value = (installmentInterests+additionalCost).toMoney(2,'.',' ');						
	}

	if(additionalCost>0)
	{
		paymentAmounts[paymentAmounts.length] = additionalCost;
		paymentTerms[paymentTerms.length] = 0;
	}

	form.resultAPR.value = round(rrso(loanInterest,creditAmount,paymentAmounts,paymentTerms)*100,2).toMoney(2,'.',' ');		

/*
kwota zaciągniętego kredytu (kwota początkowa) = 100 000 zł
oprocentowanie w skali roku =  3,5%
okres kredytu = 12 lat
ilość rat w roku = 12

Pierwsza rata:
część kapitałowa = 100 000/(12*12) = 694,44 zł
część odsetkowa = 100 000 * 3,5%/12 = 291,67 zł
rata = 694,44 + 291,67 = 986,11 zł

Druga rata:
część kapitałowa = 100 000/(12*12) = 694,44 zł
część odsetkowa = (100 000 - 694,44) * 3,5%/12 = 289,64 zł
rata = 694,44 + 289,64 = 984,08 zł*/
	
/*
S – kwota zaciągniętego kredytu
n – ilość rat
q – współczynnik równy 1 + (r / m), gdzie
q^n – „q” do potęgi „n”
r – oprocentowanie kredytu
m – ilość rat w okresie dla którego obowiązuje oprocentowanie „r”. Najczęściej oprocentowanie podawanej jest w skali roku, a raty płacone są co miesiąc, więc „m” wtedy jest równe 12.	
	*/
}

function rrso(interest,amount,paymentAmounts,paymentTerms)
{
	var a = 0;
	var b = interest;
		
	while(rrso_single(b,amount,paymentAmounts,paymentTerms)<0) b *= 2;
	
	var avg;
	do
	{
		var avg = (a+b)/2;
		res = rrso_single(avg,amount,paymentAmounts,paymentTerms);
		if(res<0)
			a = avg;
		else
			b = avg;
	}while(Math.abs(res)>0.001);
			
	return avg;
}

function rrso_single(interest,amount,paymentAmounts,paymentTerms)
{
	var res = 0;
	
	for(var i=0; i<paymentAmounts.length; i++)
	{
		res += paymentAmounts[i]/Math.pow(1+interest,paymentTerms[i]/360);
	}

	return amount-res;
}

function activateForm()
{    
    activeForm++;
	
	document.getElementById("loan_view_"+activeForm).style.removeProperty("display");
	
	document.forms[activeForm].loanAmount.value = document.forms[activeForm-1].loanAmount.value;
	document.forms[activeForm].loanInterest.value = document.forms[activeForm-1].loanInterest.value;
	document.forms[activeForm].loanComissionType.value = document.forms[activeForm-1].loanComissionType.value;
	document.forms[activeForm].loanComissionValue.value = document.forms[activeForm-1].loanComissionValue.value;

	document.forms[activeForm].loanComissionValueType.value = document.forms[activeForm-1].loanComissionValueType.value;
	document.forms[activeForm].loanTermNumber.value = document.forms[activeForm-1].loanTermNumber.value;
	document.forms[activeForm].loanTermType.value = document.forms[activeForm-1].loanTermType.value;
	document.forms[activeForm].loanInstallmentType.value = document.forms[activeForm-1].loanInstallmentType.value;
	
	recalculate(document.forms[activeForm].loanAmount,document.forms[activeForm]);
	
	if(activeForm==document.forms.length-1)
	{		
		document.getElementById("loan_view_activation").style.display = "none";
	}
	
	return false;
}

function selectInput(field)
{
	addClass(field,"input_selected");
	
	for(var i = 0; i < field.form.elements.length; i++)
   {
		var currentElement = field.form.elements[i];
		
		if(currentElement == field)
			continue;
			
		removeClass(currentElement,"input_selected");
	}
}
function addClass(item, classname) 
{
    var obj = item
    if (typeof item=="string") {
        obj = document.getElementById(item)
    }
    obj.className += " " + classname
}

function removeClass(item, classname) 
{
    var obj = item
    if (typeof item=="string") {
        obj = document.getElementById(item)
    }
    var classes = ""+obj.className
    while (classes.indexOf(classname)>-1) {
        classes = classes.replace (classname, "")
    }
    obj.className = classes
}

Number.prototype.toMoney = function(decimals, decimalSeparator, thousandsSeparator)
{ 
   var n = this;
   c = isNaN(decimals) ? 2 : Math.abs(decimals);
   d = decimalSeparator || '.';
   t = (typeof thousandsSeparator === 'undefined') ? ' ' : thousandsSeparator;
   sign = (n < 0) ? '-' : '',

   i = parseInt(n = Math.abs(n).toFixed(c)) + '', 
   j = ((j = i.length) > 3) ? j % 3 : 0; 

   return sign + (j ? i.substr(0, j) + t : '') + i.substr(j).replace(/(\d{3})(?=\d)/g, "$1" + t) + (c ? d + Math.abs(n - i).toFixed(c).slice(2) : ''); 
}