WIP
This commit is contained in:
Nathan Anderson
@@ -0,0 +1,295 @@
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import 'package:flutter/foundation.dart';
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class CardDetails {
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CardDetails({required this.cardNumber, required String? securityCode, required this.expirationDate}) {
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this.securityCode = int.tryParse(securityCode ?? '');
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checkIsValid();
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}
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factory CardDetails.blank() {
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return CardDetails(cardNumber: null, securityCode: null, expirationDate: null);
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}
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String? cardNumber;
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int? securityCode;
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String? postalCode;
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String? expirationDate;
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bool _complete = false;
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ValidState _validState = ValidState.blank;
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int _lastCheckHash = 0;
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CardProvider? provider;
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ValidState get validState {
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checkIsValid();
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return _validState;
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}
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bool get cardNumberFilled => provider == null || provider?.cardLength == cardNumber?.replaceAll(' ', '').length;
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bool get isComplete {
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checkIsValid();
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return _complete;
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}
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int get minInnLength => 1;
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int get maxINNLength => 4;
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void checkIsValid() {
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try {
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int currentHash = hash;
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if (currentHash == _lastCheckHash) {
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return;
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}
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_lastCheckHash = currentHash;
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if (cardNumber == null && expirationDate == null && securityCode == null && postalCode == null) {
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_complete = false;
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_validState = ValidState.blank;
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return;
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}
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final nums = cardNumber!
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.replaceAll(' ', '')
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.split('')
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.map(
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(i) => int.parse(i),
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)
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.toList();
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if (!luhnAlgorithmCheck(nums)) {
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_complete = false;
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_validState = ValidState.invalidCard;
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return;
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}
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if (cardNumber == null || !cardNumberFilled) {
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_complete = false;
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_validState = ValidState.missingCard;
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return;
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}
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if (expirationDate == null) {
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_complete = false;
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_validState = ValidState.missingDate;
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return;
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}
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final expSplits = expirationDate!.split('/');
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if (expSplits.length != 2 || expSplits.last == '') {
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_complete = false;
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_validState = ValidState.missingDate;
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return;
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}
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final date = DateTime(2000 + int.parse(expSplits.last),
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int.parse(expSplits.first[0] == '0' ? expSplits.first[1] : expSplits.first));
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if (date.isBefore(DateTime.now())) {
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_complete = false;
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_validState = ValidState.dateTooEarly;
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return;
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} else if (date.isAfter(DateTime.now().add(const Duration(days: 365 * 50)))) {
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_complete = false;
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_validState = ValidState.dateTooLate;
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return;
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}
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if (securityCode == null) {
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_complete = false;
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_validState = ValidState.missingCVC;
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return;
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}
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if (postalCode == null) {
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_complete = false;
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_validState = ValidState.missingZip;
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return;
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}
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if (!RegExp(r'^\d{5}(-\d{4})?$').hasMatch(postalCode!)) {
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_complete = false;
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_validState = ValidState.invalidZip;
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return;
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}
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_complete = true;
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_validState = ValidState.ok;
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} catch (err, st) {
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if (kDebugMode) {
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print('Error while validating CardDetails: $err\n$st');
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}
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_complete = false;
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_validState = ValidState.error;
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}
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}
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int get hash {
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return Object.hash(cardNumber, expirationDate, securityCode, postalCode);
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}
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void detectCardProvider() {
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bool found = false;
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if (cardNumber == null) {
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return;
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}
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for (var cardPvd in providers) {
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if (cardPvd.INN_VALID_NUMS != null) {
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// trim card number to correct length
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String trimmedNum = cardNumber!;
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String innNumStr = '${cardPvd.INN_VALID_NUMS!.first}';
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if (trimmedNum.length > innNumStr.length) {
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trimmedNum = trimmedNum.substring(0, innNumStr.length);
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}
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final num = int.tryParse(trimmedNum);
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if (num == null) continue;
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if (cardPvd.INN_VALID_NUMS!.contains(num)) {
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provider = cardPvd;
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found = true;
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break;
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}
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}
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if (cardPvd.INN_VALID_RANGES != null) {
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// trim card number to correct length
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String trimmedNum = cardNumber!;
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String innNumStr = '${cardPvd.INN_VALID_RANGES!.first.low}';
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if (trimmedNum.length > innNumStr.length) {
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trimmedNum = trimmedNum.substring(0, innNumStr.length);
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}
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final num = int.tryParse(trimmedNum);
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if (num == null) continue;
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if (cardPvd.INN_VALID_RANGES!.any((range) => range.isWithin(num))) {
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provider = cardPvd;
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found = true;
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break;
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}
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}
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}
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if (!found) provider = null;
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// print('Got provider $provider');
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}
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@override
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String toString() {
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return 'Number: "$cardNumber" - Exp: "$expirationDate" CVC: $securityCode Zip: "$postalCode"';
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}
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}
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enum ValidState {
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ok,
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error,
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blank,
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missingCard,
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invalidCard,
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missingDate,
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dateTooEarly,
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dateTooLate,
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missingCVC,
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invalidCVC,
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missingZip,
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invalidZip,
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}
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enum CardProviderID {
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AmericanExpress,
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DinersClub,
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DiscoverCard,
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Mastercard,
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JCB,
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Visa,
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}
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class CardProvider {
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CardProviderID id;
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List<int>? INN_VALID_NUMS;
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List<Range>? INN_VALID_RANGES;
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int cardLength;
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int cvcLength;
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CardProvider(
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{required this.id,
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required this.cardLength,
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required this.cvcLength,
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this.INN_VALID_NUMS,
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this.INN_VALID_RANGES}) {
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// Must provide one or the other
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assert(INN_VALID_NUMS != null || INN_VALID_RANGES != null);
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// Do not provide empty list of valid nums
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assert(INN_VALID_NUMS == null || INN_VALID_NUMS!.isNotEmpty);
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}
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@override
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String toString() {
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return id.toString();
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}
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}
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class Range {
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int high;
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int low;
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Range({required this.low, required this.high}) {
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assert(low <= high);
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}
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bool isWithin(int val) {
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return low <= val && val <= high;
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}
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}
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List<CardProvider> providers = [
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CardProvider(
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id: CardProviderID.AmericanExpress,
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cardLength: 15,
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cvcLength: 4,
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INN_VALID_NUMS: [34, 37],
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),
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CardProvider(
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id: CardProviderID.DinersClub,
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cardLength: 16,
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cvcLength: 3,
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INN_VALID_NUMS: [30, 36, 38, 39],
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),
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CardProvider(
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id: CardProviderID.DiscoverCard,
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cardLength: 16,
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cvcLength: 3,
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INN_VALID_NUMS: [60, 65],
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INN_VALID_RANGES: [Range(low: 644, high: 649)],
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),
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CardProvider(
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id: CardProviderID.JCB,
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cardLength: 16,
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cvcLength: 3,
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INN_VALID_NUMS: [35],
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),
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CardProvider(
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id: CardProviderID.Mastercard,
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cardLength: 16,
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cvcLength: 3,
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INN_VALID_RANGES: [Range(low: 22, high: 27), Range(low: 51, high: 55)],
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),
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CardProvider(
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id: CardProviderID.Visa,
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cardLength: 16,
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cvcLength: 3,
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INN_VALID_NUMS: [4],
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)
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];
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// https://en.wikipedia.org/wiki/Luhn_algorithm
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// The Luhn algorithm is used in industry to check
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// for valid credit / debit card numbers
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//
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// The algorithm adds together all the numbers, every
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// other number is doubled, then the sum is checked to
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// see if it is a multiple of 10.
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bool luhnAlgorithmCheck(List<int> digits) {
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int sum = 0;
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bool isSecond = false;
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for (int i = digits.length - 1; i >= 0; i--) {
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int d = digits[i];
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if (isSecond) {
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d *= 2;
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if (d > 9) {
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d -= 9;
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}
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}
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sum += d;
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isSecond = !isSecond;
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}
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return (sum % 10) == 0;
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}
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