/*================================================================================================*/
/*
*
* donwloaded from http://www.braemoor.co.uk/software/creditcard.shtml
* adapted by Valerie Isaksen
*
*/
/*

This routine checks the credit card number. The following checks are made:

1. A number has been provided
2. The number is a right length for the card
3. The number has an appropriate prefix for the card
4. The number has a valid modulus 10 number check digit if required

If the validation fails an error is reported.

The structure of credit card formats was gleaned from a variety of sources on the web, although the
best is probably on Wikepedia ("Credit card number"):

  http://en.wikipedia.org/wiki/Credit_card_number

Parameters:
            cardnumber           number on the card
            cardname             name of card as defined in the card list below

 Author:     John Gardner
 Date:       1st November 2003
 Updated:    26th Feb. 2005      Additional cards added by request
 Updated:    27th Nov. 2006      Additional cards added from Wikipedia
 Updated:    18th Jan. 2008      Additional cards added from Wikipedia
 Updated:    26th Nov. 2008      Maestro cards extended
 Updated:    19th Jun. 2009      Laser cards extended from Wikipedia
 Updated:    11th Sep. 2010      Typos removed from Diners and Solo definitions (thanks to Noe Leon)
 Updated:    10th April 2012     New matches for Maestro, Diners Enroute and Switch
 Updated:    17th October 2012   Diners Club prefix 38 not encoded

 */

/*
   If a credit card number is invalid, an error reason is loaded into the global ccErrorNo variable.
   This can be be used to index into the global error  string array to report the reason to the user
   if required:

   e.g. if (!checkCreditCard (number, name) alert (ccErrors(ccErrorNo);
*/

var ccErrorNo = 0;


/*************************************************************************\
boolean isExpiryDate([int year, int month])
return true if the date is a valid expiry date,
else return false.
\*************************************************************************/
function CreditCardisExpiryDate(month, year,paymentmethod_id) {
    document.getElementById("cc_expiredate_errormsg_"+paymentmethod_id).style.display="none";
    document.getElementById("cc_expiredate_errormsg_"+paymentmethod_id).innerHTML ='';
    today = new Date();
    expiry = new Date(year, month);
    if (today.getTime() > expiry.getTime()) {
	var error_msg =  ccErrors [5] ;
	document.getElementById("cc_expiredate_errormsg_"+ paymentmethod_id).style.display="block";
	document.getElementById("cc_expiredate_errormsg_"+ paymentmethod_id).innerHTML =error_msg;
	return false;
    }
    else
	return true;
}






function CheckCreditCardNumber(cardnumber, paymentmethod_id){
    for (cardType = 0; cardType < 13 ; cardType++) {
	if(checkCreditCard(cardnumber,cardType)){
	    return true;
	}
    }
    var error_msg =  ccErrors [ccErrorNo] ;
    document.getElementById("cc_cardnumber_errormsg_"+ paymentmethod_id).style.display="block";
    document.getElementById("cc_cardnumber_errormsg_"+ paymentmethod_id).innerHTML =error_msg;

    return false;
}
function razCCerror(paymentmethod_id){

    document.getElementById("cc_cardnumber_errormsg_" + paymentmethod_id).style.display="none";
    document.getElementById("cc_cardnumber_errormsg_" + paymentmethod_id).innerHTML ='';

    return true;
}
function checkCreditCard (cardnumber, cardname) {

    // Array to hold the permitted card characteristics
    var cards = new Array();

    // Define the cards we support. You may add addtional card types as follows.

    //  Name:         As in the selection box of the form - must be same as user's
    //  Length:       List of possible valid lengths of the card number for the card
    //  prefixes:     List of possible prefixes for the card
    //  checkdigit:   Boolean to say whether there is a check digit

    cards [0] = {name: "Visa",
        length: "13,16",
        prefixes: "4",
        checkdigit: true};
    cards [1] = {name: "MasterCard",
        length: "16",
        prefixes: "51,52,53,54,55",
        checkdigit: true};
    cards [2] = {name: "DinersClub",
        length: "14,16",
        prefixes: "36,38,54,55",
        checkdigit: true};
    cards [3] = {name: "CarteBlanche",
        length: "14",
        prefixes: "300,301,302,303,304,305",
        checkdigit: true};
    cards [4] = {name: "AmEx",
        length: "15",
        prefixes: "34,37",
        checkdigit: true};
    cards [5] = {name: "Discover",
        length: "16",
        prefixes: "6011,622,64,65",
        checkdigit: true};
    cards [6] = {name: "JCB",
        length: "16",
        prefixes: "35",
        checkdigit: true};
    cards [7] = {name: "enRoute",
        length: "15",
        prefixes: "2014,2149",
        checkdigit: true};
    cards [8] = {name: "Solo",
        length: "16,18,19",
        prefixes: "6334,6767",
        checkdigit: true};
    cards [9] = {name: "Switch",
        length: "16,18,19",
        prefixes: "4903,4905,4911,4936,564182,633110,6333,6759",
        checkdigit: true};
    cards [10] = {name: "Maestro",
        length: "12,13,14,15,16,18,19",
        prefixes: "5018,5020,5038,6304,6759,6761,6762,6763",
        checkdigit: true};
    cards [11] = {name: "VisaElectron",
        length: "16",
        prefixes: "4026,417500,4508,4844,4913,4917",
        checkdigit: true};
    cards [12] = {name: "LaserCard",
        length: "16,17,18,19",
        prefixes: "6304,6706,6771,6709",
        checkdigit: true};

    // Establish card type
    var cardType = -1;
    for (var i=0; i<cards.length; i++) {

        // See if it is this card (ignoring the case of the string)
        if (typeof cardname != 'undefined')
            if (cardname != null)
                if (cardname.toLowerCase () == cards[i].name.toLowerCase()) {
                    cardType = i;
                    break;
                }
    }

    // If card type not found, report an error
    if (cardType == -1) {
        ccErrorNo = 0;
        return false;
    }

    // Ensure that the user has provided a credit card number
    if (cardnumber.length == 0)  {
        ccErrorNo = 1;
        return false;
    }

    // Now remove any spaces from the credit card number
    cardnumber = cardnumber.replace (/\s/g, "");

    // Check that the number is numeric
    var cardNo = cardnumber
    var cardexp = /^[0-9]{13,19}$/;
    if (!cardexp.exec(cardNo))  {
        ccErrorNo = 2;
        return false;
    }

    // Now check the modulus 10 check digit - if required
    if (cards[cardType].checkdigit) {
        var checksum = 0;                                  // running checksum total
        var mychar = "";                                   // next char to process
        var j = 1;                                         // takes value of 1 or 2

        // Process each digit one by one starting at the right
        var calc;
        for (i = cardNo.length - 1; i >= 0; i--) {

            // Extract the next digit and multiply by 1 or 2 on alternative digits.
            calc = Number(cardNo.charAt(i)) * j;

            // If the result is in two digits add 1 to the checksum total
            if (calc > 9) {
                checksum = checksum + 1;
                calc = calc - 10;
            }

            // Add the units element to the checksum total
            checksum = checksum + calc;

            // Switch the value of j
            if (j ==1) {j = 2} else {j = 1};
        }

        // All done - if checksum is divisible by 10, it is a valid modulus 10.
        // If not, report an error.
        if (checksum % 10 != 0)  {
            ccErrorNo = 3;
            return false;
        }
    }

    // Check it's not a spam number
    if (cardNo == '5490997771092064') {
        ccErrorNo = 5;
        return false;
    }

    // The following are the card-specific checks we undertake.
    var LengthValid = false;
    var PrefixValid = false;
    var undefined;

    // We use these for holding the valid lengths and prefixes of a card type
    var prefix = new Array ();
    var lengths = new Array ();

    // Load an array with the valid prefixes for this card
    prefix = cards[cardType].prefixes.split(",");

    // Now see if any of them match what we have in the card number
    for (i=0; i<prefix.length; i++) {
        var exp = new RegExp ("^" + prefix[i]);
        if (exp.test (cardNo)) PrefixValid = true;
    }

    // If it isn't a valid prefix there's no point at looking at the length
    if (!PrefixValid) {
        ccErrorNo = 3;
        return false;
    }

    // See if the length is valid for this card
    lengths = cards[cardType].length.split(",");
    for (j=0; j<lengths.length; j++) {
        if (cardNo.length == lengths[j]) LengthValid = true;
    }

    // See if all is OK by seeing if the length was valid. We only check the length if all else was
    // hunky dory.
    if (!LengthValid) {
        ccErrorNo = 4;
        return false;
    };

    // The credit card is in the required format.
    return true;
}

/*================================================================================================*/
