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

function initialize()
{
	newParticipant();
	recalculate(document.itemForm1.itemName);
}

function modifyParticipant(field)
{
	var form = field.form;
	var index = form.name.substring(15);

	if(form.participantName.value && index==newParticipantIndex)
		newParticipant();

	for (var i = 0; i < document.forms.length; i++)
	{
		if(document.forms[i].name.startsWith("itemForm"))
		{
			var itemForm = document.forms[i];
			if(form.participantName.value)
			{
				var optionIndex = selectOptionIndexByValue(itemForm.itemPays,index);
				if(optionIndex>=0)
				{
					itemForm.itemPays.options[optionIndex].text = form.participantName.value;
					itemForm.itemShouldPay.options[optionIndex].text = form.participantName.value;
				}
				else
					{
						itemForm.itemPays.options.add(new Option(form.participantName.value,index));
						itemForm.itemShouldPay.options.add(new Option(form.participantName.value,index));
					}
			}else 
				{
					selectRemoveByValue(itemForm.itemPays,index);
					selectRemoveByValue(itemForm.itemShouldPay,index);
				}
		}
	}

	recalculate(document.itemForm1.itemName); 
}

var newParticipantIndex = 1;

function newParticipant()
{
	var participantDiv = document.getElementById("participantPanel1");
	newParticipantIndex++;	

	var newParticipantNode = participantDiv.cloneNode(true);

	newParticipantNode.getAttributeNode("id").value = "participantPanel"+newParticipantIndex;
	
	newParticipantNode.innerHTML = newParticipantNode.innerHTML.replace("participantForm1","participantForm"+newParticipantIndex);	
	newParticipantNode.innerHTML = newParticipantNode.innerHTML.replace("input_selected","");
	
	participantDiv.parentNode.appendChild(newParticipantNode);
}

var newItemIndex = 1;

function newItem()
{
	var itemDiv = document.getElementById("itemPanel1");
	newItemIndex++;
	
	var newItemNode = itemDiv.cloneNode(true);

	newItemNode.getAttributeNode("id").value = "itemPanel"+newItemIndex;

	newItemNode.innerHTML = newItemNode.innerHTML.replace("itemForm1","itemForm"+newItemIndex);
	newItemNode.innerHTML = newItemNode.innerHTML.replace("input_selected","");
	
	itemDiv.parentNode.appendChild(newItemNode);
}

function selectOptionIndexByValue(select, value)
{
	for (var i = select.options.length-1; i >= 0 ; i--)
	{
		if(select.options[i].value == value)
		{
			return i;
		}
	}
	return -1;
}

function selectRemoveByValue(select, value)
{
	for (var i = select.options.length-1; i >= 0 ; i--)
	{
		if(select.options[i].value == value)
		{
			select.options.remove(i);
		}
	}
}

function recalculate(field)
{
	var index = field.form.name.substring(8);
	if(field.form.itemName.value && index==newItemIndex)
		newItem();
	
	var total = 0.0;
	var totalPaid = 0.0;
	var participants = 0;
	var names = Array();
	var paid = Array();
	var shouldPay = Array();

	for (var i = 0; i < document.forms.length; i++)
	{
		if(document.forms[i].name.startsWith("participantForm"))
		{
			var participantForm = document.forms[i];
			var index = participantForm.name.substring(15);
			
			if(participantForm.participantName.value)
			{			
				names[index] = participantForm.participantName.value; 			
			
				if(participantForm.participantAmount.value)
				{
					var participantAmount = parseFloat(participantForm.participantAmount.value);
					paid[index] = participantAmount;
					totalPaid += participantAmount;
				}else 
				{
					paid[index] = 0;
				}				
				shouldPay[index] = 0;
				participants++;
			}
		}
	}

	for (var i = 0; i < document.forms.length; i++)
	{		
		if(document.forms[i].name.startsWith("itemForm"))
		{
			var itemForm = document.forms[i];
			if(itemForm.itemAmount.value)
			{
				var itemAmount = parseFloat(itemForm.itemAmount.value);
				total = total + itemAmount;
				
				switch(itemForm.itemPays.value)
				{
					case "-1"://ze wspolnej puli
						break;
					case "-2":
						alert("tego jeszcze nie ma");
						break;
					default:
						paid[itemForm.itemPays.value] += itemAmount;
						totalPaid += itemAmount;
						break;
				}
			
				switch(itemForm.itemShouldPay.value)
				{
					case "-1"://po równo
						for(var j = 0; j < shouldPay.length; j++)
							if(names[j]) shouldPay[j] += itemAmount/participants;
						break;
					case "-2":
						alert("tego jeszcze nie ma");
						break;
					default:
						shouldPay[itemForm.itemShouldPay.value] += itemAmount;
						break;
				}
			}
		}
	}

	var resultDiv = document.getElementById("splitBillResult");

	resultDiv.innerHTML = "Należność w sumie: <b>"+total.toMoney(2,'.',' ')+"</b>. Zapłacono: <b>"+totalPaid.toMoney(2,'.',' ')+"</b>.<br/><br/>";
	/*for(var i = 1; i < names.length; i++)
	{
		resultDiv.innerHTML += i.toString()+". ";
		if(names[i]) resultDiv.innerHTML += names[i]+" ";
		if(paid[i]) resultDiv.innerHTML += "paid: "+paid[i].toMoney(2,'.',' ')+", ";
		if(shouldPay[i]) resultDiv.innerHTML += "should: "+shouldPay[i].toMoney(2,'.',' ');
		resultDiv.innerHTML += "<br/>";
	}*/

	var diff = Array();
	for(var i = 1; i < names.length; i++)
	{
		if(names[i])
			diff[i] = paid[i] - shouldPay[i];
	}	
	
	var finished = false;

	while(!finished)
	{
		var minIndex = 0;
		var maxIndex = 0;

		for(var i = 1; i < names.length; i++)
		{
			if(diff[i])
			{
				if(minIndex <=0 || diff[i]<diff[minIndex])
					minIndex = i;
				if(maxIndex <=0 || diff[i]>diff[maxIndex])
					maxIndex = i;
			}
		}
	
		if(minIndex==0 || diff[minIndex]>=0 || diff[maxIndex]<=0)
		{
			finished = true;//all amounts has the same sign
			continue;	
		}
	
		if(minIndex != maxIndex)
		{
			if( -diff[minIndex] > diff[maxIndex])
			{
				resultDiv.innerHTML += "<b>"+names[minIndex] +"</b> oddaje <b>"+names[maxIndex]+"</b>: <b>"+diff[maxIndex].toMoney(2,'.',' ')+"</b>.<br/>";
				
				diff[minIndex] += diff[maxIndex];
				diff[maxIndex] = 0;
			}else 
				{
					resultDiv.innerHTML += "<b>"+names[minIndex] +"</b> oddaje <b>"+names[maxIndex]+"</b>: <b>"+(-diff[minIndex]).toMoney(2,'.',' ')+"</b>.<br/>";

					diff[maxIndex] += diff[minIndex];
					diff[minIndex] = 0;
				}
		}
	}

	for(var i = 1; i < names.length; i++)
	{
		if(names[i] && round(diff[i],2)!=0)
		{
			if(diff[i]>0)
				resultDiv.innerHTML += "<b>"+names[i] +"</b> ma nadpłatę <b>"+diff[i].toMoney(2,'.',' ')+"</b>.<br/>";
			else 
				resultDiv.innerHTML += "<b>"+names[i] +"</b> musi dopłacić <b>"+(-diff[i]).toMoney(2,'.',' ')+"</b>.<br/>";
		}
	}

}

function validate(field)
{
		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;
}

function selectInput(field)
{
	addClass(field,"input_selected");
	
	for(var i = 0; i < document.forms.length; i++)	
		for(var j = 0; j < document.forms[i].elements.length; j++)
   	{
			var currentElement = document.forms[i].elements[j];
		
			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) : ''); 
}

String.prototype.startsWith = function (str)
{
    return this.indexOf(str) == 0;
};