// Original:  Simon Tneoh (tneohcb@pc.jaring.my)
//
// This script and many more are available free online at
// The JavaScript Source!! http://javascript.internet.com 

var Cards = new makeArray(8);
flag = true;

Cards[0] = new CardType("MasterCard", "51,52,53,54,55", "16");
var MasterCard = Cards[0];
Cards[1] = new CardType("VisaCard", "4", "13,16");
var VisaCard = Cards[1];
Cards[2] = new CardType("AmExCard", "34,37", "15");
var AmExCard = Cards[2];
Cards[3] = new CardType("DinersClubCard", "30,36,38", "14");
var DinersClubCard = Cards[3];
Cards[4] = new CardType("DiscoverCard", "6011", "16");
var DiscoverCard = Cards[4];
Cards[5] = new CardType("enRouteCard", "2014,2149", "15");
var enRouteCard = Cards[5];
Cards[6] = new CardType("JCBCard", "3088,3096,3112,3158,3337,3528", "16");
var JCBCard = Cards[6];
var LuhnCheckSum = Cards[7] = new CardType();

/*************************************************************************\
CheckCardNumber(type,number,month,year)
function called when users click the "check" button.
\*************************************************************************/
function CheckCardNumber(type,number,month,year) {
  var retval = eval(type + ".checkCardNumber(\"" + number + "\", " + year + ", " + month + ");");
  if (retval) {
    // comment this out if used on an order form
    //alert("This card number appears to be valid.");
    return true;
  }else {
    return false;
  }
}
/*************************************************************************\
FindCardName(number,month,year)
\*************************************************************************/
function FindCardName(number,month,year) {
  // The cardnumber has the valid luhn checksum, but we want to know which
  // cardtype it belongs to.
  for (var n = 0; n < Cards.size; n++) {
    if (Cards[n].checkCardNumber(number, year, month)) {
      return Cards[n].getCardType();
    }
  }
  return "";
}
/*************************************************************************\
Object CardType([String cardtype, String rules, String len, int year, 
                                        int month])
cardtype    : type of card, eg: MasterCard, Visa, etc.
rules       : rules of the cardnumber, eg: "4", "6011", "34,37".
len         : valid length of cardnumber, eg: "16,19", "13,16".
year        : year of expiry date.
month       : month of expiry date.
eg:
var VisaCard = new CardType("Visa", "4", "16");
var AmExCard = new CardType("AmEx", "34,37", "15");
\*************************************************************************/
function CardType() {
  var n;
  var argv = CardType.arguments;
  var argc = CardType.arguments.length;

  this.objname = "object CardType";

  var tmpcardtype = (argc > 0) ? argv[0] : "CardObject";
  var tmprules = (argc > 1) ? argv[1] : "0,1,2,3,4,5,6,7,8,9";
  var tmplen = (argc > 2) ? argv[2] : "13,14,15,16,19";

  this.setCardNumber = setCardNumber;  // set CardNumber method.
  this.setCardType = setCardType;  // setCardType method.
  this.setLen = setLen;  // setLen method.
  this.setRules = setRules;  // setRules method.
  this.setExpiryDate = setExpiryDate;  // setExpiryDate method.

  this.setCardType(tmpcardtype);
  this.setLen(tmplen);
  this.setRules(tmprules);
  if (argc > 4)
    this.setExpiryDate(argv[3], argv[4]);

  this.checkCardNumber = checkCardNumber;  // checkCardNumber method.
  this.getExpiryDate = getExpiryDate;  // getExpiryDate method.
  this.getCardType = getCardType;  // getCardType method.
  this.isCardNumber = isCardNumber;  // isCardNumber method.
  this.isExpiryDate = isExpiryDate;  // isExpiryDate method.
  this.luhnCheck = luhnCheck;// luhnCheck method.
  return this;
}

/*************************************************************************\
boolean checkCardNumber([String cardnumber, int year, int month])
return true if cardnumber pass the luhncheck and the expiry date is
valid, else return false.
\*************************************************************************/
function checkCardNumber() {
  var argv = checkCardNumber.arguments;
  var argc = checkCardNumber.arguments.length;
  var cardnumber = (argc > 0) ? argv[0] : this.cardnumber;
  var year = (argc > 1) ? argv[1] : this.year;
  var month = (argc > 2) ? argv[2] : this.month;

  this.setCardNumber(cardnumber);
  this.setExpiryDate(year, month);

  if (!this.isCardNumber())
  return false;
  if (!this.isExpiryDate())
  return false;

  return true;
}
/*************************************************************************\
String getCardType()
return the cardtype.
\*************************************************************************/
function getCardType() {
  return this.cardtype;
}
/*************************************************************************\
String getExpiryDate()
return the expiry date.
\*************************************************************************/
function getExpiryDate() {
  return this.month + "/" + this.year;
}
/*************************************************************************\
boolean isCardNumber([String cardnumber])
return true if cardnumber pass the luhncheck and the rules, else return
false.
\*************************************************************************/
function isCardNumber() {
  var argv = isCardNumber.arguments;
  var argc = isCardNumber.arguments.length;
  var cardnumber = (argc > 0) ? argv[0] : this.cardnumber;
  if (!this.luhnCheck())
  return false;

  for (var n = 0; n < this.len.size; n++)
  if (cardnumber.toString().length == this.len[n]) {
    for (var m = 0; m < this.rules.size; m++) {
      var headdigit = cardnumber.substring(0, this.rules[m].toString().length);
      if (headdigit == this.rules[m]) return true;
    }
    return false;
  }
  return false;
}

/*************************************************************************\
boolean isExpiryDate([int year, int month])
return true if the date is a valid expiry date,
else return false.
\*************************************************************************/
function isExpiryDate() {
  var argv = isExpiryDate.arguments;
  var argc = isExpiryDate.arguments.length;

  year = argc > 0 ? argv[0] : this.year;
  month = argc > 1 ? argv[1] : this.month;

  if (!isNum(year+""))
  return false;
  if (!isNum(month+""))
  return false;
  today = new Date();
  expiry = new Date(year, month);
  if (today.getTime() > expiry.getTime())
    return false;
  else
    return true;
}

/*************************************************************************\
boolean isNum(String argvalue)
return true if argvalue contains only numeric characters,
else return false.
\*************************************************************************/
function isNum(argvalue) {
  argvalue = argvalue.toString();

  if (argvalue.length == 0)
  return false;

  for (var n = 0; n < argvalue.length; n++)
    if (argvalue.substring(n, n+1) < "0" || argvalue.substring(n, n+1) > "9") return false;

  return true;
}

/*************************************************************************\
boolean luhnCheck([String CardNumber])
return true if CardNumber pass the luhn check else return false.
Reference: http://www.ling.nwu.edu/~sburke/pub/luhn_lib.pl
\*************************************************************************/
function luhnCheck() {
  var argv = luhnCheck.arguments;
  var argc = luhnCheck.arguments.length;

  var CardNumber = argc > 0 ? argv[0] : this.cardnumber;

  if (! isNum(CardNumber)) {
    return false;
  }

  var no_digit = CardNumber.length;
  var oddoeven = no_digit & 1;
  var sum = 0;

  for (var count = 0; count < no_digit; count++) {
  var digit = parseInt(CardNumber.charAt(count));
  if (!((count & 1) ^ oddoeven)) {
    digit *= 2;
    if (digit > 9)
      digit -= 9;
    }
    sum += digit;
  }
  if (sum % 10 == 0)
    return true;
  else
    return false;
}

/*************************************************************************\
ArrayObject makeArray(int size)
return the array object in the size specified.
\*************************************************************************/
function makeArray(size) {
  this.size = size;
  return this;
}

/*************************************************************************\
CardType setCardNumber(cardnumber)
return the CardType object.
\*************************************************************************/
function setCardNumber(cardnumber) {
  this.cardnumber = cardnumber;
  return this;
}

/*************************************************************************\
CardType setCardType(cardtype)
return the CardType object.
\*************************************************************************/
function setCardType(cardtype) {
  this.cardtype = cardtype;
  return this;
}

/*************************************************************************\
CardType setExpiryDate(year, month)
return the CardType object.
\*************************************************************************/
function setExpiryDate(year, month) {
  this.year = year;
  this.month = month;
  return this;
}

/*************************************************************************\
CardType setLen(len)
return the CardType object.
\*************************************************************************/
function setLen(len) {
  // Create the len array.
  if (len.length == 0 || len == null)
  len = "13,14,15,16,19";

  var tmplen = len;
  n = 1;
  while (tmplen.indexOf(",") != -1) {
    tmplen = tmplen.substring(tmplen.indexOf(",") + 1, tmplen.length);
    n++;
  }
  this.len = new makeArray(n);
  n = 0;
  while (len.indexOf(",") != -1) {
    var tmpstr = len.substring(0, len.indexOf(","));
    this.len[n] = tmpstr;
    len = len.substring(len.indexOf(",") + 1, len.length);
    n++;
  }
  this.len[n] = len;
  return this;
}

/*************************************************************************\
CardType setRules()
return the CardType object.
\*************************************************************************/
function setRules(rules) {
  // Create the rules array.
  if (rules.length == 0 || rules == null)
    rules = "0,1,2,3,4,5,6,7,8,9";
  
  var tmprules = rules;
  n = 1;
  while (tmprules.indexOf(",") != -1) {
    tmprules = tmprules.substring(tmprules.indexOf(",") + 1, tmprules.length);
    n++;
  }
  this.rules = new makeArray(n);
  n = 0;
  while (rules.indexOf(",") != -1) {
    var tmpstr = rules.substring(0, rules.indexOf(","));
    this.rules[n] = tmpstr;
    rules = rules.substring(rules.indexOf(",") + 1, rules.length);
    n++;
  }
  this.rules[n] = rules;
  return this;
}