// Form Field Validation Functions:
//
// isValidExpDate(formField,fieldLabel,required)
//   -- checks for date in the format MM/YY or MM/YYYY against the current date
// isValidCreditCardNumber(formField,ccType,fieldLabel,required)
//   -- checks for valid credit card format using the Luhn check and known digits about various cards
//

function validRequired(formField,fieldLabel) {
	var result = true;
	
	if (formField.value == "") {
		alert('Please enter a value for the "' + fieldLabel +'" field.');
		formField.focus();
		result = false;
	}
	
	return result;
}



function allDigits(str) {
	return inValidCharSet(str,"0123456789");
}



function inValidCharSet(str,charset) {
	var result = true;
	
	for (var i=0;i<str.length;i++)
		if (charset.indexOf(str.substr(i,1))<0) {
			result = false;
			break;
		}
	
	return result;
}



function isValidExpDate(formField,fieldLabel,required) {
	var result = true;
	var formValue = formField;

	if (required && !validRequired(formField,fieldLabel))
		result = false;
  
 	if (result && (formField.length>0)) {
 		var elems = formValue.split("/");
 		
 		result = (elems.length == 2); // should be two components
 		var expired = false;
		
		
 		
 		if (result) {
 			var month = parseInt(elems[0],10);
 			var year = parseInt(elems[1],10);
 			if (elems[1].length == 2)
 				year += 2000;
 			
 			var now = new Date();
 			
 			var nowMonth = now.getMonth() + 1;
 			var nowYear = now.getFullYear();
 			
 			expired = (nowYear > year) || ((nowYear == year ) && (nowMonth > month));
 			
			result = allDigits(elems[0]) && (month > 0) && (month < 13) && allDigits(elems[1]) && ((elems[1].length == 2) || (elems[1].length == 4));
 		}
 		
  		if (!result) {
 			alert('Please enter a date in the format MM/YY for the "' + fieldLabel +'" field.');
			//formField.focus();
		} else if (expired) {
 			result = false;
 			alert('The date for "' + fieldLabel +'" has expired.');
			//formField.focus();
		}
	} 
	
	return result;
}



function isValidCreditCardNumber(formField,ccType,fieldLabel,required) {
	var result = true;
 	var ccNum = formField.value;

	if (required && !validRequired(formField,fieldLabel))
		result = false;
 
  	if (result && (formField.value.length>0)) { 
 		if (!allDigits(ccNum)) {
 			alert('Please enter only numbers (no dashes or spaces) for the "' + fieldLabel +'" field.');
			formField.focus();
			result = false;
		}	

		if (result) {  			
 			if (!validateCCNum(ccType,ccNum)) {
 				alert('Please enter a valid card number for the "' + fieldLabel +'" field.');
				formField.focus();
				result = false;
			}	
		} 

	} 
	
	return result;
}



function LuhnCheck(str) {

  var result = true;

  var sum = 0; 
  var mul = 1; 
  var strLen = str.length;
  
  for (i = 0; i < strLen; i++) {
    var digit = str.substring(strLen-i-1,strLen-i);
    var tproduct = parseInt(digit ,10)*mul;
    if (tproduct >= 10)
      sum += (tproduct % 10) + 1;
    else
      sum += tproduct;
    if (mul == 1)
      mul++;
    else
      mul--;
  }
  if ((sum % 10) != 0)
    result = false;
    
  return result;
}



function GetRadioValue(rArray) {
	for (var i=0;i<rArray.length;i++) {
		if (rArray[i].checked)
			return rArray[i].value;
	}
	
	return null;
}



function validateCCNum(cardType,cardNum) {
	var result = false;
	cardType = cardType.value.toUpperCase();

	if (cardType == "MC") {cardType = "MASTERCARD";}
	
	var cardLen = cardNum.length;
	var firstdig = cardNum.substring(0,1);
	var seconddig = cardNum.substring(1,2);
	var first4digs = cardNum.substring(0,4);

	switch (cardType) {
		case "VISA":
			result = ((cardLen == 16) || (cardLen == 13)) && (firstdig == "4");
			break;
		case "AMEX":
			var validNums = "47";
			result = (cardLen == 15) && (firstdig == "3") && (validNums.indexOf(seconddig)>=0);
			break;
		case "MASTERCARD":
		case "MASTER CARD":
			var validNums = "12345";
			result = (cardLen == 16) && (firstdig == "5") && (validNums.indexOf(seconddig)>=0);
			break;
		case "DISCOVER":
			result = (cardLen == 16) && (first4digs == "6011");
			break;
		case "DINERS":
			var validNums = "068";
			result = (cardLen == 14) && (firstdig == "3") && (validNums.indexOf(seconddig)>=0);
			break;
	}
	
	if (!result)
		return result;
	else
	{
		// run luhn check
		return LuhnCheck(cardNum);
	}
}



function validCCForm(ccTypeField,ccNumField,cboExpMonth,cboExpYear) {
	var expDate = cboExpMonth.value+'/'+cboExpYear.value;
	var result = isValidCreditCardNumber(ccNumField,ccTypeField,"Credit Card Number",true) && isValidExpDate(expDate,"Expiration Date",true);
	return result;
}

function verifyCode(inField)
{
	if(inField.value.search(/^[0-9]{3,4}$/) != -1)
		return true;
	else
	{
		alert("Please enter only 3 numbers (Visa/MC) or 4 numbers (Amex)  for your Validation Code.");
		inField.focus();
		return false;
	}
}