var creditCards = Array();
var creditCardLengths = '';
function fillCards() {
    //name, prefix, length 
    creditCards[creditCards.length] = Array('Amex', 34, 15);
    creditCards[creditCards.length] = Array('Amex', 37, 15);
    creditCards[creditCards.length] = Array('Visa', 4, 13);
    creditCards[creditCards.length] = Array('Visa', 4, 16);
    creditCards[creditCards.length] = Array('Mastercard', 51, 16);
    creditCards[creditCards.length] = Array('Mastercard', 52, 16);
    creditCards[creditCards.length] = Array('Mastercard', 53, 16);
    creditCards[creditCards.length] = Array('Mastercard', 54, 16);
    creditCards[creditCards.length] = Array('Mastercard', 55, 16);
    creditCards[creditCards.length] = Array('Diners', 300, 14);
    creditCards[creditCards.length] = Array('Diners', 301, 14);
    creditCards[creditCards.length] = Array('Diners', 302, 14);
    creditCards[creditCards.length] = Array('Diners', 303, 14);
    creditCards[creditCards.length] = Array('Diners', 304, 14);
    creditCards[creditCards.length] = Array('Diners', 305, 14);
    creditCards[creditCards.length] = Array('Diners', 36, 14);
    creditCards[creditCards.length] = Array('Diners', 38, 14);
    creditCards[creditCards.length] = Array('Discover', 6011, 16);
    creditCards[creditCards.length] = Array('Maestro', 5020, 16);
    creditCards[creditCards.length] = Array('Maestro', 5038, 16);
    creditCards[creditCards.length] = Array('Maestro', 6304, 16);
    creditCards[creditCards.length] = Array('Maestro', 6759, 16);
    creditCards[creditCards.length] = Array('Maestro', 6761, 16);
    creditCards[creditCards.length] = Array('Maestro', 5020, 18);
    creditCards[creditCards.length] = Array('Maestro', 5038, 18);
    creditCards[creditCards.length] = Array('Maestro', 6304, 18);
    creditCards[creditCards.length] = Array('Maestro', 6759, 18);
    creditCards[creditCards.length] = Array('Maestro', 6761, 18);
    creditCards[creditCards.length] = Array('Switch', 6759, 16);
    creditCards[creditCards.length] = Array('Switch', 6759, 18);
    creditCards[creditCards.length] = Array('Switch', 6759, 19);
    creditCards[creditCards.length] = Array('Switch', 6333, 16);
    creditCards[creditCards.length] = Array('Switch', 6333, 18);
    creditCards[creditCards.length] = Array('Switch', 6333, 19);
    creditCards[creditCards.length] = Array('Switch', 633110, 16);
    creditCards[creditCards.length] = Array('Switch', 633110, 18);
    creditCards[creditCards.length] = Array('Switch', 633110, 19);
    creditCards[creditCards.length] = Array('Switch', 564182, 16);
    creditCards[creditCards.length] = Array('Switch', 564182, 18);
    creditCards[creditCards.length] = Array('Switch', 564182, 19);
    for (i in creditCards) {
        if (creditCardLengths.indexOf(creditCards[i][2]) < 0) {
            creditCardLengths += ' ' + creditCards[i][2] + ' ';
        }
    }
} fillCards();

function isNumeric(ch) {
    var code = ch.charCodeAt(0);
    return (code >= 48 && code <= 57)
}

function ccValidate(ccnumIn) {
    //strip out all non numeric characters
    //we must do this before checking the length
    var ccnum = stripNonNumeric(ccnumIn);

    //if the length of the card is not acceptable, then jump out now
    if (creditCardLengths.indexOf(' ' + ccnum.length + ' ') < 0) return false;

    //look for valid prefix corresponding card length
    var i = -1;
    var cardMapFound = false;
    while (!cardMapFound && i < creditCards.length - 1) {
        ++i;
        cardMapFound = ccnum.indexOf(creditCards[i][1]) == 0 && creditCards[i][2] == ccnum.length;
    }

    //if a card map was found and perform validation
    return cardMapFound && luhnValidate(ccnum);
}

function ccBankId(ccnumIn) {
    var i = 0;
    var ccArr = null;
    ccnumIn = stripNonNumeric(ccnumIn);
    if (creditCardLengths.indexOf(ccnumIn.length) < 0) return '';
    for (i = 0; i < creditCards.length; i++) {
        ccArr = creditCards[i];
        if (ccnumIn.indexOf(ccArr[1]) == 0 && ccnumIn.length == ccArr[2])
            return ccArr[0];
    }
    return '';
}

function luhnValidate(luhnIn) {
    var luhn = '';
    var anum = 0;
    var sum = 0;
    var digits = '';
    var j = 0;
    var k = 0;

    //reverse string and strip out all non numeric characters
    for (j = luhnIn.length; j >= 0; j--)
        if (isNumeric(luhnIn.charAt(j)))
        luhn += luhnIn.charAt(j);

    for (j = 0; j < luhn.length; j++) {
        anum = luhn.charCodeAt(j) - 48;
        if (j % 2 != 0)
            anum *= 2;
        digits = '' + anum;
        for (k = 0; k < digits.length; k++)
            sum += digits.charCodeAt(k) - 48;
    }
    if (sum % 10 == 0) {
        return true;
    }
}

function stripNonNumeric(str) {
    var j;
    var numerics = '';
    for (j = 0; j < str.length; j++)
        if (isNumeric(str.charAt(j)))
        numerics += str.charAt(j);
    return numerics;
}