$( document ).ready(function() {

	$( "#card_details" ).submit(function( event ) {
		return validate_card_details_form();
	});

});




function validate_card_details_form() {

	var valid = true;
	
	if ($("#chname").val() == "") {
		$( "#chname").next().html("You must put the cardholder name");
		valid = false;
	}
	else
		$( "#chname").next().html('');

	if ($("#expiry_month").val() == "" || $("#expiry_year").val() == "") {
		$( "#expiry").next().html("You must select an expiry date");
		valid = false;
	}
	else
		$( "#expiry").next().html('');


	if ($("#card_type").val() == "") {
		$( "#card_type").next().html("You must select a card type");
		valid = false;
	}
	else
		$( "#card_type").next().html('');

	if ($("#cardnumber").val() == "") {
		$( "#cardnumber").next().html("You must put a card card number");
		valid = false;
	}
	else if (!valid_credit_card($("#cardnumber").val())) {
		$( "#cardnumber").next().html("The card number is invalid");
		valid = false;
	}
	else
		$( "#cardnumber").next().html('');



	return valid;
	
}

function valid_credit_card(value) {
  // accept only digits, dashes or spaces
	if (/[^0-9-\s]+/.test(value)) return false;
 
	// The Luhn Algorithm. It's so pretty.
	var nCheck = 0, nDigit = 0, bEven = false;
	value = value.replace(/\D/g, "");
 
	for (var n = value.length - 1; n >= 0; n--) {
		var cDigit = value.charAt(n),
			  nDigit = parseInt(cDigit, 10);
 
		if (bEven) {
			if ((nDigit *= 2) > 9) nDigit -= 9;
		}
 
		nCheck += nDigit;
		bEven = !bEven;
	}
 
	return (nCheck % 10) == 0;
}