Flutter upgrade

lib/anypay/any_pay_payment.dart

@@ -6,14 +6,14 @@ import 'package:cake_wallet/monero/monero.dart';
 
 class AnyPayPayment {
 	AnyPayPayment({
-		@required this.time,
-		@required this.expires,
-		@required this.memo,
-		@required this.paymentUrl,
-		@required this.paymentId,
-		@required this.chain,
-		@required this.network,
-		@required this.instructions});
+		required this.time,
+		required this.expires,
+		required this.memo,
+		required this.paymentUrl,
+		required this.paymentId,
+		required this.chain,
+		required this.network,
+		required this.instructions});
 
 	factory AnyPayPayment.fromMap(Map<String, dynamic> obj) {
 		final instructions = (obj['instructions'] as List<dynamic>)
@@ -45,13 +45,13 @@ class AnyPayPayment {
 				.fold<int>(0, (int outAcc, out) => outAcc + out.amount));
 		switch (chain) {
 			case AnyPayChain.xmr:
-				return monero.formatterMoneroAmountToString(amount: total);
+				return monero!.formatterMoneroAmountToString(amount: total);
 			case AnyPayChain.btc:
-				return bitcoin.formatterBitcoinAmountToString(amount: total);
+				return bitcoin!.formatterBitcoinAmountToString(amount: total);
 			case AnyPayChain.ltc:
-				return bitcoin.formatterBitcoinAmountToString(amount: total);
+				return bitcoin!.formatterBitcoinAmountToString(amount: total);
 			default:
-				return null;
+				return '';
 		}
 	}
 

lib/anypay/any_pay_payment_committed_info.dart

@@ -3,11 +3,11 @@ import 'package:cake_wallet/anypay/any_pay_trasnaction.dart';
 
 class AnyPayPaymentCommittedInfo {
 	const AnyPayPaymentCommittedInfo({
-		@required this.uri,
-		@required this.currency,
-		@required this.chain,
-		@required this.transactions,
-		@required this.memo});
+		required this.uri,
+		required this.currency,
+		required this.chain,
+		required this.transactions,
+		required this.memo});
 
 	final String uri;
 	final String currency;

lib/anypay/any_pay_payment_instruction.dart

@@ -3,11 +3,11 @@ import 'package:cake_wallet/anypay/any_pay_payment_instruction_output.dart';
 
 class AnyPayPaymentInstruction {
 	AnyPayPaymentInstruction({
-		@required this.type,
-		@required this.requiredFeeRate,
-		@required this.txKey,
-		@required this.txHash,
-		@required this.outputs});
+		required this.type,
+		required this.requiredFeeRate,
+		required this.txKey,
+		required this.txHash,
+		required this.outputs});
 
 	factory AnyPayPaymentInstruction.fromMap(Map<String, dynamic> obj) {
 		final outputs = (obj['outputs'] as List<dynamic>)

lib/anypay/any_pay_trasnaction.dart

@@ -1,9 +1,7 @@
-import 'package:flutter/foundation.dart';
-
 class AnyPayTransaction {
-	const AnyPayTransaction(this.tx, {@required this.id, @required this.key});
+	const AnyPayTransaction(this.tx, {required this.id, required this.key});
 
 	final String tx;
 	final String id;
-	final String key;
+	final String? key;
 }

lib/anypay/anypay_api.dart

@@ -33,15 +33,15 @@ class AnyPayApi {
 			case 'litecoin':
 				return CryptoCurrency.ltc;
 			default:
-				return null;
+				throw Exception('Unexpected scheme: ${scheme}');
 		}
 	}
 
 	Future<AnyPayPayment> paymentRequest(String uri) async {
 		final fragments = uri.split(':?r=');
 		final scheme = fragments.first;
-		final url = fragments[1];
-  		final headers = <String, String>{
+		final url = Uri.parse(fragments[1]);
+  	final headers = <String, String>{
   			'Content-Type': contentTypePaymentRequest,
   			'X-Paypro-Version': xPayproVersion,
   			'Accept': '*/*',};
@@ -50,20 +50,20 @@ class AnyPayApi {
 			'currency': currencyByScheme(scheme).title};
 		final response = await post(url, headers: headers, body: utf8.encode(json.encode(body)));
 
-    	if (response.statusCode != 200) {
-			return null;
+    if (response.statusCode != 200) {
+      throw Exception('Unexpected response http code: ${response.statusCode}');
 		}
 
-    	final decodedBody = json.decode(response.body) as Map<String, dynamic>;
-    	return AnyPayPayment.fromMap(decodedBody);
+    final decodedBody = json.decode(response.body) as Map<String, dynamic>;
+    return AnyPayPayment.fromMap(decodedBody);
 	}
 
 	Future<AnyPayPaymentCommittedInfo> payment(
 		String uri,
-		{@required String chain,
-			@required String currency,
-			@required List<AnyPayTransaction> transactions}) async {
-  		final headers = <String, String>{
+		{required String chain,
+			required String currency,
+			required List<AnyPayTransaction> transactions}) async {
+  	final headers = <String, String>{
   			'Content-Type': contentTypePayment,
   			'X-Paypro-Version': xPayproVersion,
   			'Accept': '*/*',};
@@ -71,7 +71,7 @@ class AnyPayApi {
 			'chain': chain,
 			'currency': currency,
 			'transactions': transactions.map((tx) => {'tx': tx.tx, 'tx_hash': tx.id, 'tx_key': tx.key}).toList()};
-		final response = await post(uri, headers: headers, body: utf8.encode(json.encode(body)));
+		final response = await post(Uri.parse(uri), headers: headers, body: utf8.encode(json.encode(body)));
 		if (response.statusCode == 400) {
 			final decodedBody = json.decode(response.body) as Map<String, dynamic>;
 			throw Exception(decodedBody['message'] as String);

lib/bitcoin/cw_bitcoin.dart

@@ -5,15 +5,24 @@ class CWBitcoin extends Bitcoin {
 	TransactionPriority getMediumTransactionPriority() => BitcoinTransactionPriority.medium;	
 
 	@override
-	WalletCredentials createBitcoinRestoreWalletFromSeedCredentials({String name, String mnemonic, String password})
+	WalletCredentials createBitcoinRestoreWalletFromSeedCredentials({
+    required String name,
+    required String mnemonic,
+    required String password})
 		=> BitcoinRestoreWalletFromSeedCredentials(name: name, mnemonic: mnemonic, password: password);
 	
 	@override
-	WalletCredentials createBitcoinRestoreWalletFromWIFCredentials({String name, String password, String wif, WalletInfo walletInfo})
+	WalletCredentials createBitcoinRestoreWalletFromWIFCredentials({
+    required String name,
+    required String password,
+    required String wif,
+    WalletInfo? walletInfo})
 		=> BitcoinRestoreWalletFromWIFCredentials(name: name, password: password, wif: wif, walletInfo: walletInfo);
 	
 	@override
-	WalletCredentials createBitcoinNewWalletCredentials({String name, WalletInfo walletInfo})
+	WalletCredentials createBitcoinNewWalletCredentials({
+    required String name,
+    WalletInfo? walletInfo})
 		=> BitcoinNewWalletCredentials(name: name, walletInfo: walletInfo);
 
 	@override
@@ -55,7 +64,7 @@ class CWBitcoin extends Bitcoin {
 	}
 	
 	@override
-	Object createBitcoinTransactionCredentials(List<Output> outputs, {TransactionPriority priority, int feeRate})
+	Object createBitcoinTransactionCredentials(List<Output> outputs, {required TransactionPriority priority, int? feeRate})
 		=> BitcoinTransactionCredentials(
 			outputs.map((out) => OutputInfo(
 					fiatAmount: out.fiatAmount,
@@ -71,7 +80,7 @@ class CWBitcoin extends Bitcoin {
 			feeRate: feeRate);
 
 	@override
-	Object createBitcoinTransactionCredentialsRaw(List<OutputInfo> outputs, {TransactionPriority priority, int feeRate})
+	Object createBitcoinTransactionCredentialsRaw(List<OutputInfo> outputs, {TransactionPriority? priority, required int feeRate})
 		=> BitcoinTransactionCredentials(
 				outputs,
 				priority: priority != null ? priority as BitcoinTransactionPriority : null,
@@ -92,11 +101,11 @@ class CWBitcoin extends Bitcoin {
 	}
 
 	@override
-	String formatterBitcoinAmountToString({int amount})
+	String formatterBitcoinAmountToString({required int amount})
 		=> bitcoinAmountToString(amount: amount);
 
 	@override	
-	double formatterBitcoinAmountToDouble({int amount})
+	double formatterBitcoinAmountToDouble({required int amount})
 		=> bitcoinAmountToDouble(amount: amount);
 
 	@override	

lib/buy/buy_amount.dart

@@ -2,13 +2,13 @@ import 'package:flutter/foundation.dart';
 
 class BuyAmount {
   BuyAmount({
-    @required this.sourceAmount,
-    @required this.destAmount,
+    required this.sourceAmount,
+    required this.destAmount,
     this.achSourceAmount,
     this.minAmount = 0});
 
   final double sourceAmount;
   final double destAmount;
-  final double achSourceAmount;
+  final double? achSourceAmount;
   final int minAmount;
 }

lib/buy/buy_exception.dart

@@ -2,7 +2,7 @@ import 'package:flutter/foundation.dart';
 import 'package:cake_wallet/buy/buy_provider_description.dart';
 
 class BuyException implements Exception {
-  BuyException({@required this.description, @required this.text});
+  BuyException({required this.description, required this.text});
 
   final BuyProviderDescription description;
   final String text;

lib/buy/buy_provider.dart

@@ -5,7 +5,7 @@ import 'package:cw_core/wallet_base.dart';
 import 'package:cw_core/wallet_type.dart';
 
 abstract class BuyProvider {
-  BuyProvider({this.wallet, this.isTestEnvironment});
+  BuyProvider({required this.wallet, required this.isTestEnvironment});
 
   final WalletBase wallet;
   final bool isTestEnvironment;

lib/buy/buy_provider_description.dart

@@ -2,20 +2,20 @@ import 'package:cw_core/enumerable_item.dart';
 
 class BuyProviderDescription extends EnumerableItem<int>
     with Serializable<int> {
-    const BuyProviderDescription({String title, int raw})
+    const BuyProviderDescription({required String title, required int raw})
       : super(title: title, raw: raw);
 
     static const wyre = BuyProviderDescription(title: 'Wyre', raw: 0);
     static const moonPay = BuyProviderDescription(title: 'MoonPay', raw: 1);
 
-    static BuyProviderDescription deserialize({int raw}) {
+    static BuyProviderDescription deserialize({required int raw}) {
       switch (raw) {
         case 0:
           return wyre;
         case 1:
           return moonPay;
         default:
-          return null;
+          throw Exception('Incorrect token $raw  for BuyProviderDescription deserialize');
       }
     }
 }

lib/buy/get_buy_provider_icon.dart

@@ -1,7 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:cake_wallet/buy/buy_provider_description.dart';
 
-Image getBuyProviderIcon(BuyProviderDescription providerDescription,
+Image? getBuyProviderIcon(BuyProviderDescription providerDescription,
    {Color iconColor = Colors.black}) {
 
   final _wyreIcon =

lib/buy/moonpay/moonpay_buy_provider.dart

@@ -23,7 +23,7 @@ class MoonPaySellProvider {
   final bool isTest;
   final String baseUrl;
 
-  Future<String> requestUrl({CryptoCurrency currency, String refundWalletAddress}) async {
+  Future<String> requestUrl({required CryptoCurrency currency, required String refundWalletAddress}) async {
     final originalUri = Uri.https(
       baseUrl, '', <String, dynamic>{
         'apiKey': _apiKey,
@@ -48,10 +48,9 @@ class MoonPaySellProvider {
 }
 
 class MoonPayBuyProvider extends BuyProvider {
-  MoonPayBuyProvider({WalletBase wallet, bool isTestEnvironment = false})
-      : super(wallet: wallet, isTestEnvironment: isTestEnvironment) {
-      baseUrl = isTestEnvironment ? _baseTestUrl : _baseProductUrl;
-  }
+  MoonPayBuyProvider({required WalletBase wallet, bool isTestEnvironment = false})
+      : baseUrl = isTestEnvironment ? _baseTestUrl : _baseProductUrl,
+        super(wallet: wallet, isTestEnvironment: isTestEnvironment);
 
   static const _baseTestUrl = 'https://buy-staging.moonpay.com';
   static const _baseProductUrl = 'https://buy.moonpay.com';
@@ -109,8 +108,8 @@ class MoonPayBuyProvider extends BuyProvider {
         _quoteSuffix + '/?apiKey=' + _apiKey +
         '&baseCurrencyAmount=' + amount +
         '&baseCurrencyCode=' + sourceCurrency.toLowerCase();
-
-    final response = await get(url);
+    final uri = Uri.parse(url);
+    final response = await get(uri);
 
     if (response.statusCode != 200) {
       throw BuyException(
@@ -133,8 +132,8 @@ class MoonPayBuyProvider extends BuyProvider {
   Future<Order> findOrderById(String id) async {
     final url = _apiUrl + _transactionsSuffix + '/$id' +
         '?apiKey=' + _apiKey;
-
-    final response = await get(url);
+    final uri = Uri.parse(url);
+    final response = await get(uri);
 
     if (response.statusCode != 200) {
       throw BuyException(
@@ -164,8 +163,8 @@ class MoonPayBuyProvider extends BuyProvider {
   static Future<bool> onEnabled() async {
     final url = _apiUrl + _ipAddressSuffix + '?apiKey=' + _apiKey;
     var isBuyEnable = false;
-
-    final response = await get(url);
+    final uri = Uri.parse(url);
+    final response = await get(uri);
 
     try {
       final responseJSON = json.decode(response.body) as Map<String, dynamic>;

lib/buy/order.dart

@@ -8,18 +8,23 @@ part 'order.g.dart';
 @HiveType(typeId: Order.typeId)
 class Order extends HiveObject {
   Order(
-      {this.id,
-        BuyProviderDescription provider,
-        this.transferId,
+      {required this.id,
+        required this.transferId,
+        required this.createdAt,
+        required this.amount,
+        required this.receiveAddress,
+        required this.walletId,
+        BuyProviderDescription? provider,
+        TradeState? state,
         this.from,
-        this.to,
-        TradeState state,
-        this.createdAt,
-        this.amount,
-        this.receiveAddress,
-        this.walletId})
-      : providerRaw = provider?.raw,
-        stateRaw = state?.raw;
+        this.to}) {
+      if (provider != null) {
+        providerRaw = provider.raw;
+      }
+      if (state != null) {
+        stateRaw = state.raw;
+      }
+    }
 
   static const typeId = 8;
   static const boxName = 'Orders';
@@ -32,13 +37,13 @@ class Order extends HiveObject {
   String transferId;
 
   @HiveField(2)
-  String from;
+  String? from;
 
   @HiveField(3)
-  String to;
+  String? to;
 
   @HiveField(4)
-  String stateRaw;
+  late String stateRaw;
 
   TradeState get state => TradeState.deserialize(raw: stateRaw);
 
@@ -55,7 +60,7 @@ class Order extends HiveObject {
   String walletId;
 
   @HiveField(9)
-  int providerRaw;
+  late int providerRaw;
 
   BuyProviderDescription get provider =>
       BuyProviderDescription.deserialize(raw: providerRaw);

lib/buy/wyre/wyre_buy_provider.dart

@@ -11,12 +11,11 @@ import 'package:cake_wallet/exchange/trade_state.dart';
 import 'package:cake_wallet/.secrets.g.dart' as secrets;
 
 class WyreBuyProvider extends BuyProvider {
-  WyreBuyProvider({WalletBase wallet, bool isTestEnvironment = false})
-    : super(wallet: wallet, isTestEnvironment: isTestEnvironment) {
-    baseApiUrl = isTestEnvironment
+  WyreBuyProvider({required WalletBase wallet, bool isTestEnvironment = false})
+    : baseApiUrl = isTestEnvironment
         ? _baseTestApiUrl
-        : _baseProductApiUrl;
-  }
+        : _baseProductApiUrl,
+     super(wallet: wallet, isTestEnvironment: isTestEnvironment);
 
   static const _baseTestApiUrl = 'https://api.testwyre.com';
   static const _baseProductApiUrl = 'https://api.sendwyre.com';
@@ -50,6 +49,7 @@ class WyreBuyProvider extends BuyProvider {
     final timestamp = DateTime.now().millisecondsSinceEpoch.toString();
     final url = baseApiUrl + _ordersSuffix + _reserveSuffix +
         _timeStampSuffix + timestamp;
+    final uri = Uri.parse(url);
     final body = {
       'amount': amount,
       'sourceCurrency': sourceCurrency,
@@ -58,8 +58,7 @@ class WyreBuyProvider extends BuyProvider {
       'referrerAccountId': _accountId,
       'lockFields': ['amount', 'sourceCurrency', 'destCurrency', 'dest']
     };
-
-    final response = await post(url,
+    final response = await post(uri,
         headers: {
           'Authorization': 'Bearer $_secretKey',
           'Content-Type': 'application/json',
@@ -89,8 +88,8 @@ class WyreBuyProvider extends BuyProvider {
       'accountId': _accountId,
       'country': _countryCode
     };
-
-    final response = await post(quoteUrl,
+    final uri = Uri.parse(quoteUrl);
+    final response = await post(uri,
         headers: {
           'Authorization': 'Bearer $_secretKey',
           'Content-Type': 'application/json',
@@ -115,7 +114,8 @@ class WyreBuyProvider extends BuyProvider {
   @override
   Future<Order> findOrderById(String id) async {
     final orderUrl = baseApiUrl + _ordersSuffix + '/$id';
-    final orderResponse = await get(orderUrl);
+    final orderUri = Uri.parse(orderUrl);
+    final orderResponse = await get(orderUri);
 
     if (orderResponse.statusCode != 200) {
       throw BuyException(
@@ -136,7 +136,8 @@ class WyreBuyProvider extends BuyProvider {
 
     final transferUrl =
         baseApiUrl + _transferSuffix + transferId + _trackSuffix;
-    final transferResponse = await get(transferUrl);
+    final transferUri = Uri.parse(transferUrl);
+    final transferResponse = await get(transferUri);
 
     if (transferResponse.statusCode != 200) {
       throw BuyException(

lib/core/address_label_validator.dart

@@ -3,7 +3,7 @@ import 'package:cake_wallet/generated/i18n.dart';
 import 'package:cw_core/wallet_type.dart';
 
 class AddressLabelValidator extends TextValidator {
-  AddressLabelValidator({WalletType type})
+  AddressLabelValidator({WalletType? type})
       : super(
             errorMessage: S.current.error_text_subaddress_name,
             pattern: '''^[^`,'"]{1,20}\$''',

lib/core/address_validator.dart

@@ -4,7 +4,7 @@ import 'package:cake_wallet/core/validator.dart';
 import 'package:cw_core/crypto_currency.dart';
 
 class AddressValidator extends TextValidator {
-  AddressValidator({@required CryptoCurrency type})
+  AddressValidator({required CryptoCurrency type})
       : super(
             errorMessage: S.current.error_text_address,
             pattern: getPattern(type),
@@ -79,7 +79,7 @@ class AddressValidator extends TextValidator {
     }
   }
 
-  static List<int> getLength(CryptoCurrency type) {
+  static List<int>? getLength(CryptoCurrency type) {
     switch (type) {
       case CryptoCurrency.xmr:
         return null;

lib/core/amount.dart

@@ -1,37 +1,37 @@
-abstract class Amount {
-  Amount(this.value);
+// abstract class Amount {
+//   Amount(this.value);
 
-  int value;
+//   int value;
 
-  int minorDigits;
+//   int minorDigits;
 
-  String code;
+//   String code;
 
-  String formatted();
-}
+//   String formatted();
+// }
 
-class MoneroAmount extends Amount {
-  MoneroAmount(int value) : super(value) {
-    minorDigits = 12;
-    code = 'XMR';
-  }
+// class MoneroAmount extends Amount {
+//   MoneroAmount(int value) : super(value) {
+//     minorDigits = 12;
+//     code = 'XMR';
+//   }
 
-  // const moneroAmountLength = 12;
-  // const moneroAmountDivider = 1000000000000;
-  // final moneroAmountFormat = NumberFormat()
-  //   ..maximumFractionDigits = moneroAmountLength
-  //   ..minimumFractionDigits = 1;
+//   // const moneroAmountLength = 12;
+//   // const moneroAmountDivider = 1000000000000;
+//   // final moneroAmountFormat = NumberFormat()
+//   //   ..maximumFractionDigits = moneroAmountLength
+//   //   ..minimumFractionDigits = 1;
 
-  // String moneroAmountToString({int amount}) =>
-  //     moneroAmountFormat.format(cryptoAmountToDouble(amount: amount, divider: moneroAmountDivider));
+//   // String moneroAmountToString({int amount}) =>
+//   //     moneroAmountFormat.format(cryptoAmountToDouble(amount: amount, divider: moneroAmountDivider));
 
-  // double moneroAmountToDouble({int amount}) => cryptoAmountToDouble(amount: amount, divider: moneroAmountDivider);
+//   // double moneroAmountToDouble({int amount}) => cryptoAmountToDouble(amount: amount, divider: moneroAmountDivider);
 
-  // int moneroParseAmount({String amount}) => moneroAmountFormat.parse(amount).toInt();
+//   // int moneroParseAmount({String amount}) => moneroAmountFormat.parse(amount).toInt();
 
-  @override
-  String formatted() {
-    // TODO: implement formatted
-    throw UnimplementedError();
-  }
-}
+//   @override
+//   String formatted() {
+//     // TODO: implement formatted
+//     throw UnimplementedError();
+//   }
+// }

lib/core/amount_converter.dart

@@ -47,7 +47,7 @@ class AmountConverter {
       case CryptoCurrency.xusd:
         return _moneroAmountToDouble(amount);
       default:
-        return null;
+        return 0.0;
     }
   }
 
@@ -71,7 +71,7 @@ class AmountConverter {
       case CryptoCurrency.xusd:
         return _moneroParseAmount(amount);
       default:
-        return null;
+        return 0;
     }
   }
 
@@ -97,11 +97,11 @@ class AmountConverter {
       case CryptoCurrency.xusd:
         return _moneroAmountToString(amount);
       default:
-        return null;
+        return '';
     }
   }
 
-  static double cryptoAmountToDouble({num amount, num divider}) =>
+  static double cryptoAmountToDouble({required num amount, required num divider}) =>
       amount / divider;
 
   static String _moneroAmountToString(int amount) => _moneroAmountFormat.format(

lib/core/amount_validator.dart

@@ -3,7 +3,7 @@ import 'package:cake_wallet/generated/i18n.dart';
 import 'package:cw_core/wallet_type.dart';
 
 class AmountValidator extends TextValidator {
-  AmountValidator({WalletType type, bool isAutovalidate = false})
+  AmountValidator({required WalletType type, bool isAutovalidate = false})
       : super(
             errorMessage: S.current.error_text_amount,
             pattern: _pattern(type),

lib/core/auth_service.dart

@@ -6,12 +6,12 @@ import 'package:cake_wallet/entities/secret_store_key.dart';
 import 'package:cake_wallet/entities/encrypt.dart';
 
 class AuthService with Store {
-  AuthService({this.secureStorage, this.sharedPreferences});
+  AuthService({required this.secureStorage, required this.sharedPreferences});
 
   final FlutterSecureStorage secureStorage;
   final SharedPreferences sharedPreferences;
 
-  Future setPassword(String password) async {
+  Future<void> setPassword(String password) async {
     final key = generateStoreKeyFor(key: SecretStoreKey.pinCodePassword);
     final encodedPassword = encodedPinCode(pin: password);
     await secureStorage.write(key: key, value: encodedPassword);
@@ -24,7 +24,7 @@ class AuthService with Store {
     var password = '';
 
     try {
-      password = await secureStorage.read(key: key);
+      password = await secureStorage.read(key: key) ?? '';
     } catch (e) {
       print(e);
     }
@@ -35,7 +35,7 @@ class AuthService with Store {
   Future<bool> authenticate(String pin) async {
     final key = generateStoreKeyFor(key: SecretStoreKey.pinCodePassword);
     final encodedPin = await secureStorage.read(key: key);
-    final decodedPin = decodedPinCode(pin: encodedPin);
+    final decodedPin = decodedPinCode(pin: encodedPin!);
 
     return decodedPin == pin;
   }

lib/core/auth_state.dart

@@ -7,13 +7,13 @@ class AuthenticationInProgress extends AuthState {}
 class AuthenticatedSuccessfully extends AuthState {}
 
 class AuthenticationFailure extends AuthState {
-  AuthenticationFailure({this.error});
+  AuthenticationFailure({required this.error});
 
   final String error;
 }
 
 class AuthenticationBanned extends AuthState {
-  AuthenticationBanned({this.error});
+  AuthenticationBanned({required this.error});
 
   final String error;
 }

lib/core/backup_service.dart

@@ -20,7 +20,8 @@ import 'package:cake_wallet/wallet_types.g.dart';
 class BackupService {
   BackupService(this._flutterSecureStorage, this._walletInfoSource,
       this._keyService, this._sharedPreferences)
-      : _cipher = chacha20Poly1305Aead;
+      : _cipher = Cryptography.instance.chacha20Poly1305Aead(),
+        _correctWallets = <WalletInfo>[];
 
   static const currentVersion = _v1;
 
@@ -54,7 +55,7 @@ class BackupService {
       case _v1:
         return await _exportBackupV1(password, nonce: nonce);
       default:
-        return null;
+        throw Exception('Incorrect version: $version for exportBackup');
     }
   }
 
@@ -91,8 +92,8 @@ class BackupService {
     });
     await keychainDumpFile.writeAsBytes(keychainDump.toList());
     await preferencesDumpFile.writeAsString(preferencesDump);
-    zipEncoder.addFile(preferencesDumpFile, '~_preferences_dump');
-    zipEncoder.addFile(keychainDumpFile, '~_keychain_dump');
+    await zipEncoder.addFile(preferencesDumpFile, '~_preferences_dump');
+    await zipEncoder.addFile(keychainDumpFile, '~_keychain_dump');
     zipEncoder.close();
 
     final content = File(archivePath).readAsBytesSync();
@@ -103,7 +104,7 @@ class BackupService {
   }
 
   Future<void> _importBackupV1(Uint8List data, String password,
-      {@required String nonce}) async {
+      {required String nonce}) async {
     final appDir = await getApplicationDocumentsDirectory();
     final decryptedData = await _decrypt(data, password, nonce);
     final zip = ZipDecoder().decodeBytes(decryptedData);
@@ -214,7 +215,7 @@ class BackupService {
   }
 
   Future<void> _importKeychainDump(String password,
-      {@required String nonce,
+      {required String nonce,
       String keychainSalt = secrets.backupKeychainSalt}) async {
     final appDir = await getApplicationDocumentsDirectory();
     final keychainDumpFile = File('${appDir.path}/~_keychain_dump');
@@ -251,11 +252,11 @@ class BackupService {
   }
 
   Future<Uint8List> _exportKeychainDump(String password,
-      {@required String nonce,
+      {required String nonce,
       String keychainSalt = secrets.backupKeychainSalt}) async {
     final key = generateStoreKeyFor(key: SecretStoreKey.pinCodePassword);
     final encodedPin = await _flutterSecureStorage.read(key: key);
-    final decodedPin = decodedPinCode(pin: encodedPin);
+    final decodedPin = decodedPinCode(pin: encodedPin!);
     final wallets =
         await Future.wait(_walletInfoSource.values.map((walletInfo) async {
       return {
@@ -281,41 +282,42 @@ class BackupService {
   }
 
   Future<String> _exportPreferencesJSON() async {
+    // FIX-ME: Force unwrap
     final preferences = <String, Object>{
       PreferencesKey.currentWalletName:
-          _sharedPreferences.getString(PreferencesKey.currentWalletName),
+          _sharedPreferences.getString(PreferencesKey.currentWalletName)!,
       PreferencesKey.currentNodeIdKey:
-          _sharedPreferences.getInt(PreferencesKey.currentNodeIdKey),
+          _sharedPreferences.getInt(PreferencesKey.currentNodeIdKey)!,
       PreferencesKey.currentBalanceDisplayModeKey: _sharedPreferences
-          .getInt(PreferencesKey.currentBalanceDisplayModeKey),
+          .getInt(PreferencesKey.currentBalanceDisplayModeKey)!,
       PreferencesKey.currentWalletType:
-          _sharedPreferences.getInt(PreferencesKey.currentWalletType),
+          _sharedPreferences.getInt(PreferencesKey.currentWalletType)!,
       PreferencesKey.currentFiatCurrencyKey:
-          _sharedPreferences.getString(PreferencesKey.currentFiatCurrencyKey),
+          _sharedPreferences.getString(PreferencesKey.currentFiatCurrencyKey)!,
       PreferencesKey.shouldSaveRecipientAddressKey: _sharedPreferences
-          .getBool(PreferencesKey.shouldSaveRecipientAddressKey),
+          .getBool(PreferencesKey.shouldSaveRecipientAddressKey)!,
       PreferencesKey.isDarkThemeLegacy:
-          _sharedPreferences.getBool(PreferencesKey.isDarkThemeLegacy),
+          _sharedPreferences.getBool(PreferencesKey.isDarkThemeLegacy)!,
       PreferencesKey.currentPinLength:
-          _sharedPreferences.getInt(PreferencesKey.currentPinLength),
+          _sharedPreferences.getInt(PreferencesKey.currentPinLength)!,
       PreferencesKey.currentTransactionPriorityKeyLegacy: _sharedPreferences
-          .getInt(PreferencesKey.currentTransactionPriorityKeyLegacy),
+          .getInt(PreferencesKey.currentTransactionPriorityKeyLegacy)!,
       PreferencesKey.allowBiometricalAuthenticationKey: _sharedPreferences
-          .getBool(PreferencesKey.allowBiometricalAuthenticationKey),
+          .getBool(PreferencesKey.allowBiometricalAuthenticationKey)!,
       PreferencesKey.currentBitcoinElectrumSererIdKey: _sharedPreferences
-          .getInt(PreferencesKey.currentBitcoinElectrumSererIdKey),
+          .getInt(PreferencesKey.currentBitcoinElectrumSererIdKey)!,
       PreferencesKey.currentLanguageCode:
-          _sharedPreferences.getString(PreferencesKey.currentLanguageCode),
+          _sharedPreferences.getString(PreferencesKey.currentLanguageCode)!,
       PreferencesKey.displayActionListModeKey:
-          _sharedPreferences.getInt(PreferencesKey.displayActionListModeKey),
+          _sharedPreferences.getInt(PreferencesKey.displayActionListModeKey)!,
       PreferencesKey.currentTheme:
-          _sharedPreferences.getInt(PreferencesKey.currentTheme),
+          _sharedPreferences.getInt(PreferencesKey.currentTheme)!,
       PreferencesKey.currentDefaultSettingsMigrationVersion: _sharedPreferences
-          .getInt(PreferencesKey.currentDefaultSettingsMigrationVersion),
+          .getInt(PreferencesKey.currentDefaultSettingsMigrationVersion)!,
       PreferencesKey.bitcoinTransactionPriority:
-          _sharedPreferences.getInt(PreferencesKey.bitcoinTransactionPriority),
+          _sharedPreferences.getInt(PreferencesKey.bitcoinTransactionPriority)!,
       PreferencesKey.moneroTransactionPriority:
-          _sharedPreferences.getInt(PreferencesKey.moneroTransactionPriority),
+          _sharedPreferences.getInt(PreferencesKey.moneroTransactionPriority)!,
     };
 
     return json.encode(preferences);
@@ -330,17 +332,26 @@ class BackupService {
 
   Future<Uint8List> _encrypt(
       Uint8List data, String secretKeySource, String nonceBase64) async {
-    final secretKeyHash = await sha256.hash(utf8.encode(secretKeySource));
+    final secretKeyHash = await Cryptography.instance.sha256().hash(utf8.encode(secretKeySource));
     final secretKey = SecretKey(secretKeyHash.bytes);
-    final nonce = Nonce(base64.decode(nonceBase64));
-    return await _cipher.encrypt(data, secretKey: secretKey, nonce: nonce);
+    final nonce = base64.decode(nonceBase64).toList();
+    final box = await _cipher.encrypt(data.toList(), secretKey: secretKey, nonce: nonce);
+    return Uint8List.fromList(box.cipherText);
   }
 
   Future<Uint8List> _decrypt(
       Uint8List data, String secretKeySource, String nonceBase64) async {
-    final secretKeyHash = await sha256.hash(utf8.encode(secretKeySource));
-    final secretKey = SecretKey(secretKeyHash.bytes);
-    final nonce = Nonce(base64.decode(nonceBase64));
-    return await _cipher.decrypt(data, secretKey: secretKey, nonce: nonce);
+     throw Exception('Unimplemented');
+    //final secretKeyHash = await sha256.hash(utf8.encode(secretKeySource));
+    //final secretKey = SecretKey(secretKeyHash.bytes);
+    //final nonce = Nonce(base64.decode(nonceBase64));
+    //return await _cipher.decrypt(data, secretKey: secretKey, nonce: nonce);
+
+    // final secretKeyHash = await Cryptography.instance.sha256().hash(utf8.encode(secretKeySource));
+    // final secretKey = SecretKey(secretKeyHash.bytes);
+    // final nonce = base64.decode(nonceBase64).toList();
+    // final box = SecretBox(data.toList(), nonce: nonce, mac: Mac);
+    // final plainData = await _cipher.decrypt(box, secretKey: secretKey);
+    // return Uint8List.fromList(plainData);
   }
 }

lib/core/fiat_conversion_service.dart

@@ -16,7 +16,7 @@ Future<double> _fetchPrice(Map<String, dynamic> args) async {
     final fiatStringified = fiat.toString();
     final uri = Uri.https(fiatApiAuthority, fiatApiPath,
         <String, String>{'convert': fiatStringified});
-    final response = await get(uri.toString());
+    final response = await get(uri);
 
     if (response.statusCode != 200) {
       return 0.0;

lib/core/key_service.dart

@@ -7,15 +7,14 @@ class KeyService {
 
   final FlutterSecureStorage _secureStorage;
 
-  Future<String> getWalletPassword({String walletName}) async {
+  Future<String> getWalletPassword({required String walletName}) async {
     final key = generateStoreKeyFor(
         key: SecretStoreKey.moneroWalletPassword, walletName: walletName);
     final encodedPassword = await _secureStorage.read(key: key);
-
-    return decodeWalletPassword(password: encodedPassword);
+    return decodeWalletPassword(password: encodedPassword!);
   }
 
-  Future<void> saveWalletPassword({String walletName, String password}) async {
+  Future<void> saveWalletPassword({required String walletName, required String password}) async {
     final key = generateStoreKeyFor(
         key: SecretStoreKey.moneroWalletPassword, walletName: walletName);
     final encodedPassword = encodeWalletPassword(password: password);

lib/core/monero_account_label_validator.dart

@@ -4,7 +4,7 @@ import 'package:cake_wallet/core/validator.dart';
 import 'package:cw_core/crypto_currency.dart';
 
 class MoneroLabelValidator extends TextValidator {
-  MoneroLabelValidator({@required CryptoCurrency type})
+  MoneroLabelValidator()
       : super(
       errorMessage: S.current.error_text_account_name,
       pattern: '^[a-zA-Z0-9_ ]{1,15}\$',

lib/core/seed_validator.dart

@@ -7,23 +7,24 @@ import 'package:cake_wallet/monero/monero.dart';
 import 'package:cake_wallet/utils/language_list.dart';
 
 class SeedValidator extends Validator<MnemonicItem> {
-  SeedValidator({this.type, this.language})
-      : _words = getWordList(type: type, language: language);
+  SeedValidator({required this.type, required this.language})
+      : _words = getWordList(type: type, language: language),
+        super(errorMessage: 'Wrong seed mnemonic');
 
   final WalletType type;
   final String language;
   final List<String> _words;
 
-  static List<String> getWordList({WalletType type, String language}) {
+  static List<String> getWordList({required WalletType type, required String language}) {
     switch (type) {
       case WalletType.bitcoin:
         return getBitcoinWordList(language);
       case WalletType.litecoin:
         return getBitcoinWordList(language);
       case WalletType.monero:
-        return monero.getMoneroWordList(language);
+        return monero!.getMoneroWordList(language);
       case WalletType.haven:
-        return haven.getMoneroWordList(language);
+        return haven!.getMoneroWordList(language);
       default:
         return [];
     }
@@ -31,9 +32,9 @@ class SeedValidator extends Validator<MnemonicItem> {
 
   static List<String> getBitcoinWordList(String language) {
     assert(language.toLowerCase() == LanguageList.english.toLowerCase());
-    return bitcoin.getWordList();
+    return bitcoin!.getWordList();
   }
 
   @override
-  bool isValid(MnemonicItem value) => _words.contains(value.text);
+  bool isValid(MnemonicItem? value) => _words.contains(value?.text);
 }

lib/core/sync_status_title.dart

@@ -33,4 +33,6 @@ String syncStatusTitle(SyncStatus syncStatus) {
   if (syncStatus is LostConnectionSyncStatus) {
     return S.current.sync_status_failed_connect;
   }
+
+  return '';
 }

lib/core/validator.dart

@@ -1,13 +1,13 @@
 import 'package:flutter/foundation.dart';
 
 abstract class Validator<T> {
-  Validator({@required this.errorMessage});
+  Validator({required this.errorMessage});
 
   final String errorMessage;
 
-  bool isValid(T value);
+  bool isValid(T? value);
 
-  String call(T value) => !isValid(value) ? errorMessage : null;
+  String? call(T? value) =>  !isValid(value) ? errorMessage : null;
 }
 
 class TextValidator extends Validator<String> {
@@ -15,28 +15,28 @@ class TextValidator extends Validator<String> {
       {this.minLength,
       this.maxLength,
       this.pattern,
+      String errorMessage = '',
       this.length,
-      this.isAutovalidate = false,
-      String errorMessage})
+      this.isAutovalidate = false})
       : super(errorMessage: errorMessage);
 
-  final int minLength;
-  final int maxLength;
-  final List<int> length;
+  final int? minLength;
+  final int? maxLength;
+  final List<int>? length;
   final bool isAutovalidate;
-  String pattern;
+  String? pattern;
 
   @override
-  bool isValid(String value) {
+  bool isValid(String? value) {
     if (value == null || value.isEmpty) {
       return isAutovalidate ? true : false;
     }
 
     return value.length > (minLength ?? 0) &&
         (length?.contains(value.length) ?? true) &&
-        ((maxLength ?? 0) > 0 ? (value.length <= maxLength) : true) &&
+        ((maxLength ?? 0) > 0 ? (value.length <= maxLength!) : true) &&
         (pattern != null ? match(value) : true);
   }
 
-  bool match(String value) => RegExp(pattern).hasMatch(value);
+  bool match(String value) => pattern != null ? RegExp(pattern!).hasMatch(value) : false;
 }

lib/core/wallet_creation_service.dart

@@ -14,15 +14,13 @@ import 'package:cw_core/wallet_type.dart';
 
 class WalletCreationService {
   WalletCreationService(
-      {WalletType initialType,
-      this.secureStorage,
-      this.keyService,
-      this.sharedPreferences,
-      this.walletInfoSource})
+      {required WalletType initialType,
+      required this.secureStorage,
+      required this.keyService,
+      required this.sharedPreferences,
+      required this.walletInfoSource})
       : type = initialType {
-    if (type != null) {
-      changeWalletType(type: type);
-    }
+    changeWalletType(type: type);
   }
 
   WalletType type;
@@ -30,11 +28,11 @@ class WalletCreationService {
   final SharedPreferences sharedPreferences;
   final KeyService keyService;
   final Box<WalletInfo> walletInfoSource;
-  WalletService _service;
+  WalletService? _service;
 
   static const _isNewMoneroWalletPasswordUpdated = true;
 
-  void changeWalletType({@required WalletType type}) {
+  void changeWalletType({required WalletType type}) {
     this.type = type;
     _service = getIt.get<WalletService>(param1: type);
   }
@@ -64,7 +62,7 @@ class WalletCreationService {
     credentials.password = password;
     await keyService.saveWalletPassword(
         password: password, walletName: credentials.name);
-    final wallet =  await _service.create(credentials);
+    final wallet =  await _service!.create(credentials);
 
     if (wallet.type == WalletType.monero) {
       await sharedPreferences
@@ -82,7 +80,7 @@ class WalletCreationService {
     credentials.password = password;
     await keyService.saveWalletPassword(
         password: password, walletName: credentials.name);
-    final wallet = await _service.restoreFromKeys(credentials);
+    final wallet = await _service!.restoreFromKeys(credentials);
 
     if (wallet.type == WalletType.monero) {
       await sharedPreferences
@@ -100,7 +98,7 @@ class WalletCreationService {
     credentials.password = password;
     await keyService.saveWalletPassword(
         password: password, walletName: credentials.name);
-    final wallet = await _service.restoreFromSeed(credentials);
+    final wallet = await _service!.restoreFromSeed(credentials);
 
     if (wallet.type == WalletType.monero) {
       await sharedPreferences

lib/core/wallet_creation_state.dart

@@ -7,7 +7,7 @@ class WalletCreating extends WalletCreationState {}
 class WalletCreatedSuccessfully extends WalletCreationState {}
 
 class WalletCreationFailure extends WalletCreationState {
-  WalletCreationFailure({@required this.error});
+  WalletCreationFailure({required this.error});
 
   final String error;
 }

lib/core/wallet_loading_service.dart

@@ -17,18 +17,15 @@ class WalletLoadingService {
 	final WalletService Function(WalletType type) walletServiceFactory;
 
 	Future<WalletBase> load(WalletType type, String name) async {
-		if (walletServiceFactory == null) {
-			throw Exception('WalletLoadingService.walletServiceFactory is not set');
-		}
-		final walletService = walletServiceFactory?.call(type);
+		final walletService = walletServiceFactory.call(type);
 		final password = await keyService.getWalletPassword(walletName: name);
-  		final wallet = await walletService.openWallet(name, password);
+  	final wallet = await walletService.openWallet(name, password);
 
-  		if (type == WalletType.monero) {
-  			await upateMoneroWalletPassword(wallet);
-  		}
+  	if (type == WalletType.monero) {
+  		await upateMoneroWalletPassword(wallet);
+  	}
 
-  		return wallet;
+  	return wallet;
 	}
 
 	Future<void> upateMoneroWalletPassword(WalletBase wallet) async {

lib/di.dart

@@ -156,26 +156,26 @@ import 'package:cake_wallet/core/wallet_loading_service.dart';
 final getIt = GetIt.instance;
 
 var _isSetupFinished = false;
-Box<WalletInfo> _walletInfoSource;
-Box<Node> _nodeSource;
-Box<Contact> _contactSource;
-Box<Trade> _tradesSource;
-Box<Template> _templates;
-Box<ExchangeTemplate> _exchangeTemplates;
-Box<TransactionDescription> _transactionDescriptionBox;
-Box<Order> _ordersSource;
-Box<UnspentCoinsInfo> _unspentCoinsInfoSource;
+late Box<WalletInfo> _walletInfoSource;
+late Box<Node> _nodeSource;
+late Box<Contact> _contactSource;
+late Box<Trade> _tradesSource;
+late Box<Template> _templates;
+late Box<ExchangeTemplate> _exchangeTemplates;
+late Box<TransactionDescription> _transactionDescriptionBox;
+late Box<Order> _ordersSource;
+late Box<UnspentCoinsInfo>? _unspentCoinsInfoSource;
 
 Future setup(
-    {Box<WalletInfo> walletInfoSource,
-    Box<Node> nodeSource,
-    Box<Contact> contactSource,
-    Box<Trade> tradesSource,
-    Box<Template> templates,
-    Box<ExchangeTemplate> exchangeTemplates,
-    Box<TransactionDescription> transactionDescriptionBox,
-    Box<Order> ordersSource,
-    Box<UnspentCoinsInfo> unspentCoinsInfoSource}) async {
+    {required Box<WalletInfo> walletInfoSource,
+    required Box<Node> nodeSource,
+    required Box<Contact> contactSource,
+    required Box<Trade> tradesSource,
+    required Box<Template> templates,
+    required Box<ExchangeTemplate> exchangeTemplates,
+    required Box<TransactionDescription> transactionDescriptionBox,
+    required Box<Order> ordersSource,
+    Box<UnspentCoinsInfo>? unspentCoinsInfoSource}) async {
   _walletInfoSource = walletInfoSource;
   _nodeSource = nodeSource;
   _contactSource = contactSource;
@@ -328,9 +328,9 @@ Future setup(
                   .changeProcessText('ERROR: ${loginError.toString()}');
             }
 
-            ReactionDisposer _reaction;
-            _reaction = reaction((_) => appStore.wallet, (Object _) {
-              _reaction?.reaction?.dispose();
+            ReactionDisposer? _reaction;
+            _reaction = reaction((_) => appStore.wallet, (Object? _) {
+              _reaction?.reaction.dispose();
               authStore.allowed();
             });
           }, closable: false),
@@ -354,7 +354,7 @@ Future setup(
 
   getIt.registerFactoryParam<WalletAddressEditOrCreateViewModel, dynamic, void>(
       (dynamic item, _) => WalletAddressEditOrCreateViewModel(
-          wallet: getIt.get<AppStore>().wallet, item: item));
+          wallet: getIt.get<AppStore>().wallet!, item: item));
 
   getIt.registerFactoryParam<AddressEditOrCreatePage, dynamic, void>(
       (dynamic item, _) => AddressEditOrCreatePage(
@@ -362,13 +362,13 @@ Future setup(
               getIt.get<WalletAddressEditOrCreateViewModel>(param1: item)));
 
   getIt.registerFactory<SendTemplateViewModel>(() => SendTemplateViewModel(
-      getIt.get<AppStore>().wallet,
+      getIt.get<AppStore>().wallet!,
       getIt.get<AppStore>().settingsStore,
       getIt.get<SendTemplateStore>(),
       getIt.get<FiatConversionStore>()));
 
   getIt.registerFactory<SendViewModel>(() => SendViewModel(
-      getIt.get<AppStore>().wallet,
+      getIt.get<AppStore>().wallet!,
       getIt.get<AppStore>().settingsStore,
       getIt.get<SendTemplateViewModel>(),
       getIt.get<FiatConversionStore>(),
@@ -391,14 +391,13 @@ Future setup(
       WalletListPage(walletListViewModel: getIt.get<WalletListViewModel>()));
 
   getIt.registerFactory(() {
-    final wallet = getIt.get<AppStore>().wallet;
+    final wallet = getIt.get<AppStore>().wallet!;
 
     if (wallet.type == WalletType.monero || wallet.type == WalletType.haven) {
       return MoneroAccountListViewModel(wallet);
     }
 
-    // FIXME: throw exception.
-    return null;
+    throw Exception('Unexpected wallet type: ${wallet.type} for generate MoneroAccountListViewModel');
   });
 
   getIt.registerFactory(() => MoneroAccountListPage(
@@ -422,9 +421,9 @@ Future setup(
   getIt.registerFactoryParam<MoneroAccountEditOrCreateViewModel,
           AccountListItem, void>(
       (AccountListItem account, _) => MoneroAccountEditOrCreateViewModel(
-          monero.getAccountList(getIt.get<AppStore>().wallet),
-          haven?.getAccountList(getIt.get<AppStore>().wallet),
-          wallet: getIt.get<AppStore>().wallet,
+          monero!.getAccountList(getIt.get<AppStore>().wallet!),
+          haven?.getAccountList(getIt.get<AppStore>().wallet!),
+          wallet: getIt.get<AppStore>().wallet!,
           accountListItem: account));
 
   getIt.registerFactoryParam<MoneroAccountEditOrCreatePage, AccountListItem,
@@ -436,13 +435,13 @@ Future setup(
   getIt.registerFactory(() {
     final appStore = getIt.get<AppStore>();
     final yatStore = getIt.get<YatStore>();
-    return SettingsViewModel(appStore.settingsStore, yatStore, appStore.wallet);
+    return SettingsViewModel(appStore.settingsStore, yatStore, appStore.wallet!);
   });
 
   getIt.registerFactory(() => SettingsPage(getIt.get<SettingsViewModel>()));
 
   getIt
-      .registerFactory(() => WalletSeedViewModel(getIt.get<AppStore>().wallet));
+      .registerFactory(() => WalletSeedViewModel(getIt.get<AppStore>().wallet!));
 
   getIt.registerFactoryParam<WalletSeedPage, bool, void>(
       (bool isWalletCreated, _) => WalletSeedPage(
@@ -450,12 +449,12 @@ Future setup(
           isNewWalletCreated: isWalletCreated));
 
   getIt
-      .registerFactory(() => WalletKeysViewModel(getIt.get<AppStore>().wallet));
+      .registerFactory(() => WalletKeysViewModel(getIt.get<AppStore>().wallet!));
 
   getIt.registerFactory(() => WalletKeysPage(getIt.get<WalletKeysViewModel>()));
 
-  getIt.registerFactoryParam<ContactViewModel, ContactRecord, void>(
-      (ContactRecord contact, _) =>
+  getIt.registerFactoryParam<ContactViewModel, ContactRecord?, void>(
+      (ContactRecord? contact, _) =>
           ContactViewModel(_contactSource, contact: contact));
 
   getIt.registerFactory(
@@ -465,26 +464,26 @@ Future setup(
       (bool isEditable, _) => ContactListPage(getIt.get<ContactListViewModel>(),
           isEditable: isEditable));
 
-  getIt.registerFactoryParam<ContactPage, ContactRecord, void>(
-      (ContactRecord contact, _) =>
+  getIt.registerFactoryParam<ContactPage, ContactRecord?, void>(
+      (ContactRecord? contact, _) =>
           ContactPage(getIt.get<ContactViewModel>(param1: contact)));
 
   getIt.registerFactory(() {
     final appStore = getIt.get<AppStore>();
     return NodeListViewModel(
-        _nodeSource, appStore.wallet, appStore.settingsStore);
+        _nodeSource, appStore.wallet!, appStore.settingsStore);
   });
 
   getIt.registerFactory(() => NodeListPage(getIt.get<NodeListViewModel>()));
 
   getIt.registerFactory(() =>
-      NodeCreateOrEditViewModel(_nodeSource, getIt.get<AppStore>().wallet));
+      NodeCreateOrEditViewModel(_nodeSource, getIt.get<AppStore>().wallet!));
 
   getIt.registerFactory(
       () => NodeCreateOrEditPage(getIt.get<NodeCreateOrEditViewModel>()));
 
   getIt.registerFactory(() => ExchangeViewModel(
-      getIt.get<AppStore>().wallet,
+      getIt.get<AppStore>().wallet!,
       _tradesSource,
       getIt.get<ExchangeTemplateStore>(),
       getIt.get<TradesStore>(),
@@ -493,7 +492,7 @@ Future setup(
   ));
 
   getIt.registerFactory(() => ExchangeTradeViewModel(
-      wallet: getIt.get<AppStore>().wallet,
+      wallet: getIt.get<AppStore>().wallet!,
       trades: _tradesSource,
       tradesStore: getIt.get<TradesStore>(),
       sendViewModel: getIt.get<SendViewModel>()));
@@ -513,17 +512,17 @@ Future setup(
       (WalletType param1, __) {
     switch (param1) {
       case WalletType.haven:
-        return haven.createHavenWalletService(_walletInfoSource);
+        return haven!.createHavenWalletService(_walletInfoSource);
       case WalletType.monero:
-        return monero.createMoneroWalletService(_walletInfoSource);
+        return monero!.createMoneroWalletService(_walletInfoSource);
       case WalletType.bitcoin:
-        return bitcoin.createBitcoinWalletService(
-            _walletInfoSource, _unspentCoinsInfoSource);
+        return bitcoin!.createBitcoinWalletService(
+            _walletInfoSource, _unspentCoinsInfoSource!);
       case WalletType.litecoin:
-        return bitcoin.createLitecoinWalletService(
-            _walletInfoSource, _unspentCoinsInfoSource);
+        return bitcoin!.createLitecoinWalletService(
+            _walletInfoSource, _unspentCoinsInfoSource!);
       default:
-        return null;
+        throw Exception('Unexpected token: ${param1.toString()} for generating of WalletService');
     }
   });
 
@@ -536,7 +535,7 @@ Future setup(
           getIt.get<SetupPinCodeViewModel>(),
           onSuccessfulPinSetup: onSuccessfulPinSetup));
 
-  getIt.registerFactory(() => RescanViewModel(getIt.get<AppStore>().wallet));
+  getIt.registerFactory(() => RescanViewModel(getIt.get<AppStore>().wallet!));
 
   getIt.registerFactory(() => RescanPage(getIt.get<RescanViewModel>()));
 
@@ -553,7 +552,7 @@ Future setup(
   getIt
       .registerFactoryParam<TransactionDetailsViewModel, TransactionInfo, void>(
           (TransactionInfo transactionInfo, _) {
-    final wallet = getIt.get<AppStore>().wallet;
+    final wallet = getIt.get<AppStore>().wallet!;
     return TransactionDetailsViewModel(
         transactionInfo: transactionInfo,
         transactionDescriptionBox: _transactionDescriptionBox,
@@ -567,9 +566,8 @@ Future setup(
               getIt.get<TransactionDetailsViewModel>(param1: transactionInfo)));
 
   getIt.registerFactoryParam<NewWalletTypePage,
-          void Function(BuildContext, WalletType), bool>(
-      (para1, param2) => NewWalletTypePage(getIt.get<WalletNewVM>(),
-          onTypeSelected: para1, isNewWallet: param2));
+          void Function(BuildContext, WalletType), void>(
+      (param1, _) => NewWalletTypePage(onTypeSelected: param1));
 
   getIt.registerFactoryParam<PreSeedPage, WalletType, void>(
       (WalletType type, _) => PreSeedPage(type));
@@ -610,7 +608,7 @@ Future setup(
 
     return BuyViewModel(_ordersSource, getIt.get<OrdersStore>(),
         getIt.get<SettingsStore>(), getIt.get<BuyAmountViewModel>(),
-        wallet: wallet);
+        wallet: wallet!);
   });
 
   getIt.registerFactory(() {
@@ -627,7 +625,7 @@ Future setup(
   getIt.registerFactoryParam<OrderDetailsViewModel, Order, void>((order, _) {
     final wallet = getIt.get<AppStore>().wallet;
 
-    return OrderDetailsViewModel(wallet: wallet, orderForDetails: order);
+    return OrderDetailsViewModel(wallet: wallet!, orderForDetails: order);
   });
 
   getIt.registerFactoryParam<OrderDetailsPage, Order, void>((Order order, _) =>
@@ -641,7 +639,7 @@ Future setup(
     final wallet = getIt.get<AppStore>().wallet;
 
     return UnspentCoinsListViewModel(
-        wallet: wallet, unspentCoinsInfo: _unspentCoinsInfoSource);
+        wallet: wallet!, unspentCoinsInfo: _unspentCoinsInfoSource!);
   });
 
   getIt.registerFactory(() => UnspentCoinsListPage(
@@ -667,7 +665,7 @@ Future setup(
   getIt.registerFactory(() => YatService());
 
   getIt.registerFactory(() => AddressResolver(yatService: getIt.get<YatService>(),
-    walletType: getIt.get<AppStore>().wallet.type));
+    walletType: getIt.get<AppStore>().wallet!.type));
 
   getIt.registerFactoryParam<FullscreenQRPage, String, bool>(
           (String qrData, bool isLight) => FullscreenQRPage(qrData: qrData, isLight: isLight,));
@@ -683,7 +681,7 @@ Future setup(
       () => IoniaAnyPay(
         getIt.get<IoniaService>(),
         getIt.get<AnyPayApi>(),
-        getIt.get<AppStore>().wallet));
+        getIt.get<AppStore>().wallet!));
 
   getIt.registerFactory(() => IoniaGiftCardsListViewModel(ioniaService: getIt.get<IoniaService>()));
 

lib/entities/action_list_display_mode.dart

@@ -18,7 +18,7 @@ int serializeActionlistDisplayModes(List<ActionListDisplayMode> modes) {
 }
 
 List<ActionListDisplayMode> deserializeActionlistDisplayModes(int raw) {
-  final modes = List<ActionListDisplayMode>();
+  final modes = <ActionListDisplayMode>[];
 
   if (raw == 1 || raw - 10 == 1) {
     modes.add(ActionListDisplayMode.trades);

lib/entities/balance_display_mode.dart

@@ -3,7 +3,7 @@ import 'package:cake_wallet/generated/i18n.dart';
 import 'package:cw_core/enumerable_item.dart';
 
 class BalanceDisplayMode extends EnumerableItem<int> with Serializable<int> {
-  const BalanceDisplayMode({@required String title, @required int raw})
+  const BalanceDisplayMode({required String title, required int raw})
       : super(title: title, raw: raw);
 
   static const all = [
@@ -18,7 +18,7 @@ class BalanceDisplayMode extends EnumerableItem<int> with Serializable<int> {
   static const displayableBalance =
       BalanceDisplayMode(raw: 3, title: 'Displayable Balance');
 
-  static BalanceDisplayMode deserialize({int raw}) {
+  static BalanceDisplayMode deserialize({required int raw}) {
     switch (raw) {
       case 0:
         return fullBalance;
@@ -29,7 +29,7 @@ class BalanceDisplayMode extends EnumerableItem<int> with Serializable<int> {
       case 3:
         return displayableBalance;
       default:
-        return null;
+        throw Exception('Unexpected token: $raw for BalanceDisplayMode deserialize');
     }
   }
 

lib/entities/biometric_auth.dart

@@ -9,8 +9,9 @@ class BiometricAuth {
     try {
       return await _localAuth.authenticate(
           localizedReason: S.current.biometric_auth_reason,
-          useErrorDialogs: true,
-          stickyAuth: false);
+          options: AuthenticationOptions(
+            useErrorDialogs: true,
+            stickyAuth: false));
     } on PlatformException catch (e) {
       print(e);
     }

lib/entities/calculate_fiat_amount.dart

@@ -1,4 +1,4 @@
-String calculateFiatAmount({double price, String cryptoAmount}) {
+String calculateFiatAmount({double? price, String? cryptoAmount}) {
   if (price == null || cryptoAmount == null) {
     return '0.00';
   }

lib/entities/calculate_fiat_amount_raw.dart

@@ -1,4 +1,4 @@
-String calculateFiatAmountRaw({double price, double cryptoAmount}) {
+String calculateFiatAmountRaw({required double cryptoAmount, double? price}) {
   if (price == null) {
     return '0.00';
   }

lib/entities/contact.dart

@@ -8,8 +8,11 @@ part 'contact.g.dart';
 
 @HiveType(typeId: Contact.typeId)
 class Contact extends HiveObject with Keyable {
-  Contact({@required this.name, @required this.address, CryptoCurrency type})
-      : raw = type?.raw;
+  Contact({required this.name, required this.address, CryptoCurrency? type}) {
+    if (type != null) {
+      raw = type.raw;
+    }
+  }
 
   static const typeId = 0;
   static const boxName = 'Contacts';
@@ -21,7 +24,7 @@ class Contact extends HiveObject with Keyable {
   String address;
 
   @HiveField(2)
-  int raw;
+  late int raw;
 
   CryptoCurrency get type => CryptoCurrency.deserialize(raw: raw);
 
@@ -34,6 +37,6 @@ class Contact extends HiveObject with Keyable {
   @override
   int get hashCode => key.hashCode;
 
-  void updateCryptoCurrency({@required CryptoCurrency currency}) =>
+  void updateCryptoCurrency({required CryptoCurrency currency}) =>
       raw = currency.raw;
 }

lib/entities/contact_base.dart

@@ -1,6 +1,8 @@
 import 'package:cw_core/crypto_currency.dart';
 
 abstract class ContactBase {
+  ContactBase(this.name, this.address, this.type);
+
   String name;
 
   String address;

lib/entities/contact_record.dart

@@ -13,7 +13,10 @@ abstract class ContactRecordBase extends Record<Contact>
     with Store
     implements ContactBase {
   ContactRecordBase(Box<Contact> source, Contact original)
-      : super(source, original);
+      : name = original.name,
+        address = original.address,
+        type = original.type,
+      super(source, original);
 
   @override
   @observable

lib/entities/default_settings_migration.dart

@@ -18,6 +18,7 @@ import 'package:cake_wallet/entities/fs_migration.dart';
 import 'package:cw_core/wallet_info.dart';
 import 'package:cake_wallet/exchange/trade.dart';
 import 'package:encrypt/encrypt.dart' as encrypt;
+import 'package:collection/collection.dart';
 
 const newCakeWalletMoneroUri = 'xmr-node.cakewallet.com:18081';
 const cakeWalletBitcoinElectrumUri = 'electrum.cakewallet.com:50002';
@@ -25,13 +26,13 @@ const cakeWalletLitecoinElectrumUri = 'ltc-electrum.cakewallet.com:50002';
 const havenDefaultNodeUri = 'nodes.havenprotocol.org:443';
 
 Future defaultSettingsMigration(
-    {@required int version,
-    @required SharedPreferences sharedPreferences,
-    @required FlutterSecureStorage secureStorage,
-    @required Box<Node> nodes,
-    @required Box<WalletInfo> walletInfoSource,
-    @required Box<Trade> tradeSource,
-    @required Box<Contact> contactSource}) async {
+    {required int version,
+    required SharedPreferences sharedPreferences,
+    required FlutterSecureStorage secureStorage,
+    required Box<Node> nodes,
+    required Box<WalletInfo> walletInfoSource,
+    required Box<Trade> tradeSource,
+    required Box<Contact> contactSource}) async {
   if (Platform.isIOS) {
     await ios_migrate_v1(walletInfoSource, tradeSource, contactSource);
   }
@@ -56,7 +57,7 @@ Future defaultSettingsMigration(
               FiatCurrency.usd.toString());
           await sharedPreferences.setInt(
               PreferencesKey.currentTransactionPriorityKeyLegacy,
-              monero.getDefaultTransactionPriority().raw);
+              monero!.getDefaultTransactionPriority().raw);
           await sharedPreferences.setInt(
               PreferencesKey.currentBalanceDisplayModeKey,
               BalanceDisplayMode.availableBalance.raw);
@@ -147,7 +148,7 @@ Future defaultSettingsMigration(
       'current_default_settings_migration_version', version);
 }
 
-Future<void> replaceNodesMigration({@required Box<Node> nodes}) async {
+Future<void> replaceNodesMigration({required Box<Node> nodes}) async {
   final replaceNodes = <String, Node>{
     'eu-node.cakewallet.io:18081':
         Node(uri: 'xmr-node-eu.cakewallet.com:18081', type: WalletType.monero),
@@ -170,39 +171,33 @@ Future<void> replaceNodesMigration({@required Box<Node> nodes}) async {
 }
 
 Future<void> changeMoneroCurrentNodeToDefault(
-    {@required SharedPreferences sharedPreferences,
-    @required Box<Node> nodes}) async {
+    {required SharedPreferences sharedPreferences,
+    required Box<Node> nodes}) async {
   final node = getMoneroDefaultNode(nodes: nodes);
   final nodeId = node?.key as int ?? 0; // 0 - England
 
   await sharedPreferences.setInt('current_node_id', nodeId);
 }
 
-Node getBitcoinDefaultElectrumServer({@required Box<Node> nodes}) {
-  return nodes.values.firstWhere(
-          (Node node) => node.uri == cakeWalletBitcoinElectrumUri,
-          orElse: () => null) ??
-      nodes.values.firstWhere((node) => node.type == WalletType.bitcoin,
-          orElse: () => null);
+Node? getBitcoinDefaultElectrumServer({required Box<Node> nodes}) {
+    return nodes.values.firstWhereOrNull(
+          (Node node) => node.uriRaw == cakeWalletBitcoinElectrumUri)
+          ?? nodes.values.firstWhereOrNull((node) => node.type == WalletType.bitcoin);
 }
 
-Node getLitecoinDefaultElectrumServer({@required Box<Node> nodes}) {
-  return nodes.values.firstWhere(
-          (Node node) => node.uri == cakeWalletLitecoinElectrumUri,
-          orElse: () => null) ??
-      nodes.values.firstWhere((node) => node.type == WalletType.litecoin,
-          orElse: () => null);
+Node? getLitecoinDefaultElectrumServer({required Box<Node> nodes}) {
+    return nodes.values.firstWhereOrNull(
+          (Node node) => node.uriRaw == cakeWalletLitecoinElectrumUri)
+          ?? nodes.values.firstWhereOrNull((node) => node.type == WalletType.litecoin);
 }
 
-Node getHavenDefaultNode({@required Box<Node> nodes}) {
-  return nodes.values.firstWhere(
-          (Node node) => node.uriRaw == havenDefaultNodeUri,
-          orElse: () => null) ??
-      nodes.values.firstWhere((node) => node.type == WalletType.haven,
-          orElse: () => null);
+Node? getHavenDefaultNode({required Box<Node> nodes}) {
+    return nodes.values.firstWhereOrNull(
+          (Node node) => node.uriRaw == havenDefaultNodeUri)
+          ?? nodes.values.firstWhereOrNull((node) => node.type == WalletType.haven);
 }
 
-Node getMoneroDefaultNode({@required Box<Node> nodes}) {
+Node getMoneroDefaultNode({required Box<Node> nodes}) {
   final timeZone = DateTime.now().timeZoneOffset.inHours;
   var nodeUri = '';
 
@@ -214,14 +209,17 @@ Node getMoneroDefaultNode({@required Box<Node> nodes}) {
     nodeUri = 'xmr-node-usa-east.cakewallet.com:18081';
   }
 
-  return nodes.values
-          .firstWhere((Node node) => node.uri == nodeUri, orElse: () => null) ??
-      nodes.values.first;
+  try {
+    return nodes.values
+          .firstWhere((Node node) => node.uriRaw == nodeUri);
+  } catch(_) {
+    return nodes.values.first;
+  }
 }
 
 Future<void> changeBitcoinCurrentElectrumServerToDefault(
-    {@required SharedPreferences sharedPreferences,
-    @required Box<Node> nodes}) async {
+    {required SharedPreferences sharedPreferences,
+    required Box<Node> nodes}) async {
   final server = getBitcoinDefaultElectrumServer(nodes: nodes);
   final serverId = server?.key as int ?? 0;
 
@@ -229,8 +227,8 @@ Future<void> changeBitcoinCurrentElectrumServerToDefault(
 }
 
 Future<void> changeLitecoinCurrentElectrumServerToDefault(
-    {@required SharedPreferences sharedPreferences,
-    @required Box<Node> nodes}) async {
+    {required SharedPreferences sharedPreferences,
+    required Box<Node> nodes}) async {
   final server = getLitecoinDefaultElectrumServer(nodes: nodes);
   final serverId = server?.key as int ?? 0;
 
@@ -238,8 +236,8 @@ Future<void> changeLitecoinCurrentElectrumServerToDefault(
 }
 
 Future<void> changeHavenCurrentNodeToDefault(
-    {@required SharedPreferences sharedPreferences,
-    @required Box<Node> nodes}) async {
+    {required SharedPreferences sharedPreferences,
+    required Box<Node> nodes}) async {
   final node = getHavenDefaultNode(nodes: nodes);
   final nodeId = node?.key as int ?? 0;
 
@@ -247,8 +245,8 @@ Future<void> changeHavenCurrentNodeToDefault(
 }
 
 Future<void> replaceDefaultNode(
-    {@required SharedPreferences sharedPreferences,
-    @required Box<Node> nodes}) async {
+    {required SharedPreferences sharedPreferences,
+    required Box<Node> nodes}) async {
   const nodesForReplace = <String>[
     'xmr-node-uk.cakewallet.com:18081',
     'eu-node.cakewallet.io:18081',
@@ -256,9 +254,9 @@ Future<void> replaceDefaultNode(
   ];
   final currentNodeId = sharedPreferences.getInt('current_node_id');
   final currentNode =
-      nodes.values.firstWhere((Node node) => node.key == currentNodeId);
+      nodes.values.firstWhereOrNull((Node node) => node.key == currentNodeId);
   final needToReplace =
-      currentNode == null ? true : nodesForReplace.contains(currentNode.uri);
+      currentNode == null ? true : nodesForReplace.contains(currentNode.uriRaw);
 
   if (!needToReplace) {
     return;
@@ -268,7 +266,7 @@ Future<void> replaceDefaultNode(
       sharedPreferences: sharedPreferences, nodes: nodes);
 }
 
-Future<void> updateNodeTypes({@required Box<Node> nodes}) async {
+Future<void> updateNodeTypes({required Box<Node> nodes}) async {
   nodes.values.forEach((node) async {
     if (node.type == null) {
       node.type = WalletType.monero;
@@ -277,17 +275,17 @@ Future<void> updateNodeTypes({@required Box<Node> nodes}) async {
   });
 }
 
-Future<void> addBitcoinElectrumServerList({@required Box<Node> nodes}) async {
+Future<void> addBitcoinElectrumServerList({required Box<Node> nodes}) async {
   final serverList = await loadBitcoinElectrumServerList();
   await nodes.addAll(serverList);
 }
 
-Future<void> addLitecoinElectrumServerList({@required Box<Node> nodes}) async {
+Future<void> addLitecoinElectrumServerList({required Box<Node> nodes}) async {
   final serverList = await loadLitecoinElectrumServerList();
   await nodes.addAll(serverList);
 }
 
-Future<void> addHavenNodeList({@required Box<Node> nodes}) async {
+Future<void> addHavenNodeList({required Box<Node> nodes}) async {
   final nodeList = await loadDefaultHavenNodes();
   await nodes.addAll(nodeList);
 }
@@ -318,7 +316,7 @@ Future<void> addAddressesForMoneroWallets(
 
 Future<void> updateDisplayModes(SharedPreferences sharedPreferences) async {
   final currentBalanceDisplayMode =
-      sharedPreferences.getInt(PreferencesKey.currentBalanceDisplayModeKey);
+      sharedPreferences.getInt(PreferencesKey.currentBalanceDisplayModeKey) ?? -1;
   final balanceDisplayMode = currentBalanceDisplayMode < 2 ? 3 : 2;
   await sharedPreferences.setInt(
       PreferencesKey.currentBalanceDisplayModeKey, balanceDisplayMode);
@@ -338,11 +336,11 @@ Future<void> generateBackupPassword(FlutterSecureStorage secureStorage) async {
 Future<void> changeTransactionPriorityAndFeeRateKeys(
     SharedPreferences sharedPreferences) async {
   final legacyTransactionPriority = sharedPreferences
-      .getInt(PreferencesKey.currentTransactionPriorityKeyLegacy);
+      .getInt(PreferencesKey.currentTransactionPriorityKeyLegacy)!;
   await sharedPreferences.setInt(
       PreferencesKey.moneroTransactionPriority, legacyTransactionPriority);
   await sharedPreferences.setInt(PreferencesKey.bitcoinTransactionPriority,
-      bitcoin.getMediumTransactionPriority().serialize());
+      bitcoin!.getMediumTransactionPriority().serialize());
 }
 
 Future<void> changeDefaultMoneroNode(
@@ -383,18 +381,14 @@ Future<void> checkCurrentNodes(
       .getInt(PreferencesKey.currentLitecoinElectrumSererIdKey);
   final currentHavenNodeId = sharedPreferences
       .getInt(PreferencesKey.currentHavenNodeIdKey);
-  final currentMoneroNode = nodeSource.values.firstWhere(
-      (node) => node.key == currentMoneroNodeId,
-      orElse: () => null);
-  final currentBitcoinElectrumServer = nodeSource.values.firstWhere(
-      (node) => node.key == currentBitcoinElectrumSeverId,
-      orElse: () => null);
-  final currentLitecoinElectrumServer = nodeSource.values.firstWhere(
-      (node) => node.key == currentLitecoinElectrumSeverId,
-      orElse: () => null);
-  final currentHavenNodeServer = nodeSource.values.firstWhere(
-      (node) => node.key == currentHavenNodeId,
-      orElse: () => null);
+  final currentMoneroNode = nodeSource.values.firstWhereOrNull(
+      (node) => node.key == currentMoneroNodeId);
+  final currentBitcoinElectrumServer = nodeSource.values.firstWhereOrNull(
+      (node) => node.key == currentBitcoinElectrumSeverId);
+  final currentLitecoinElectrumServer = nodeSource.values.firstWhereOrNull(
+      (node) => node.key == currentLitecoinElectrumSeverId);
+  final currentHavenNodeServer = nodeSource.values.firstWhereOrNull(
+      (node) => node.key == currentHavenNodeId);
 
   if (currentMoneroNode == null) {
     final newCakeWalletNode =
@@ -435,12 +429,10 @@ Future<void> resetBitcoinElectrumServer(
     Box<Node> nodeSource, SharedPreferences sharedPreferences) async {
   final currentElectrumSeverId =
       sharedPreferences.getInt(PreferencesKey.currentBitcoinElectrumSererIdKey);
-  final oldElectrumServer = nodeSource.values.firstWhere(
-      (node) => node.uri.toString().contains('electrumx.cakewallet.com'),
-      orElse: () => null);
-  var cakeWalletNode = nodeSource.values.firstWhere(
-      (node) => node.uri.toString() == cakeWalletBitcoinElectrumUri,
-      orElse: () => null);
+  final oldElectrumServer = nodeSource.values.firstWhereOrNull(
+      (node) => node.uri.toString().contains('electrumx.cakewallet.com'));
+  var cakeWalletNode = nodeSource.values.firstWhereOrNull(
+      (node) => node.uri.toString() == cakeWalletBitcoinElectrumUri);
 
   if (cakeWalletNode == null) {
     cakeWalletNode =

lib/entities/encrypt.dart

@@ -1,8 +1,8 @@
 import 'package:encrypt/encrypt.dart';
-import 'package:password/password.dart';
+// import 'package:password/password.dart';
 import 'package:cake_wallet/.secrets.g.dart' as secrets;
 
-String encrypt({String source, String key, int keyLength = 16}) {
+String encrypt({required String source, required String key, int keyLength = 16}) {
   final _key = Key.fromUtf8(key);
   final iv = IV.fromLength(keyLength);
   final encrypter = Encrypter(AES(_key));
@@ -11,7 +11,7 @@ String encrypt({String source, String key, int keyLength = 16}) {
   return encrypted.base64;
 }
 
-String decrypt({String source, String key, int keyLength = 16}) {
+String decrypt({required String source, required String key, int keyLength = 16}) {
   final _key = Key.fromUtf8(key);
   final iv = IV.fromLength(keyLength);
   final encrypter = Encrypter(AES(_key));
@@ -20,33 +20,35 @@ String decrypt({String source, String key, int keyLength = 16}) {
   return decrypted;
 }
 
-String hash({String source}) {
-  final algorithm = PBKDF2();
-  final hash = Password.hash(source, algorithm);
+String hash({required String source}) {
+  // FIX-ME: Uninplemented
+  throw Exception('Unimplemented');
+  // final algorithm = PBKDF2();
+  // final hash = Password.hash(source, algorithm);
 
-  return hash;
+  // return hash;
 }
 
-String encodedPinCode({String pin}) {
+String encodedPinCode({required String pin}) {
   final source = '${secrets.salt}$pin';
 
   return encrypt(source: source, key: secrets.key);
 }
 
-String decodedPinCode({String pin}) {
+String decodedPinCode({required String pin}) {
   final decrypted = decrypt(source: pin, key: secrets.key);
 
   return decrypted.substring(secrets.key.length, decrypted.length);
 }
 
-String encodeWalletPassword({String password}) {
+String encodeWalletPassword({required String password}) {
   final source = password;
   final _key = secrets.shortKey + secrets.walletSalt;
 
   return encrypt(source: source, key: _key);
 }
 
-String decodeWalletPassword({String password}) {
+String decodeWalletPassword({required String password}) {
   final source = password;
   final _key = secrets.shortKey + secrets.walletSalt;
 

lib/entities/fiat_currency.dart

@@ -1,7 +1,7 @@
 import 'package:cw_core/enumerable_item.dart';
 
 class FiatCurrency extends EnumerableItem<String> with Serializable<String> {
-  const FiatCurrency({String symbol, this.countryCode, this.fullName}) : super(title: symbol, raw: symbol);
+  const FiatCurrency({required String symbol, required this.countryCode, required this.fullName}) : super(title: symbol, raw: symbol);
 
   final String countryCode;
   final String fullName;
@@ -81,7 +81,7 @@ class FiatCurrency extends EnumerableItem<String> with Serializable<String> {
     FiatCurrency.vef.raw: FiatCurrency.vef
   };
 
-  static FiatCurrency deserialize({String raw}) => _all[raw];
+  static FiatCurrency deserialize({required String raw}) => _all[raw]!;
 
   @override
   bool operator ==(Object other) => other is FiatCurrency && other.raw == raw;

lib/entities/fio_address_provider.dart

@@ -46,7 +46,7 @@ class FioAddressProvider {
     }
 
     if (response.statusCode != 200) {
-      return null;
+      throw Exception('Unexpected response http status: ${response.statusCode}');
     }
 
     final responseJSON = json.decode(response.body) as Map<String, dynamic>;

lib/entities/fs_migration.dart

@@ -1,5 +1,6 @@
 import 'dart:io';
 import 'dart:convert';
+import 'package:collection/collection.dart';
 import 'package:flutter_secure_storage/flutter_secure_storage.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 import 'package:hive/hive.dart';
@@ -61,31 +62,45 @@ Future<void> ios_migrate_user_defaults() async {
 
   //should we provide default btc node key?
   final activeCurrency = await ios_legacy_helper.getInt('currency');
-  final convertedCurrency = convertFiatLegacy(activeCurrency);
 
-  if (convertedCurrency != null) {
-    await prefs.setString(
+  if (activeCurrency != null) {
+    final convertedCurrency = convertFiatLegacy(activeCurrency);
+
+    if (convertedCurrency != null) {
+      await prefs.setString(
         'current_fiat_currency', convertedCurrency.serialize());
+    }
   }
 
   //translate fee priority
   final activeFeeTier = await ios_legacy_helper.getInt('saved_fee_priority');
-  await prefs.setInt('current_fee_priority', activeFeeTier);
+
+  if (activeFeeTier != null) {
+    await prefs.setInt('current_fee_priority', activeFeeTier);
+  }
 
   //translate current balance mode
   final currentBalanceMode =
       await ios_legacy_helper.getInt('display_balance_mode');
-  await prefs.setInt('current_balance_display_mode', currentBalanceMode);
+  if (currentBalanceMode != null) {
+    await prefs.setInt('current_balance_display_mode', currentBalanceMode);
+  }
 
   //translate should save recipient address
   final shouldSave =
       await ios_legacy_helper.getBool('should_save_recipient_address');
-  await prefs.setBool('save_recipient_address', shouldSave);
+  
+  if (shouldSave != null) {
+    await prefs.setBool('save_recipient_address', shouldSave);
+  }
 
   //translate biometric
   final biometricOn =
       await ios_legacy_helper.getBool('biometric_authentication_on');
-  await prefs.setBool('allow_biometrical_authentication', biometricOn);
+  
+  if (biometricOn != null) {
+    await prefs.setBool('allow_biometrical_authentication', biometricOn);
+  }
 
   //read the current theme as integer, write it back as a bool
   final currentTheme = prefs.getInt('current-theme');
@@ -97,11 +112,17 @@ Future<void> ios_migrate_user_defaults() async {
 
   //assign the pin length
   final pinLength = await ios_legacy_helper.getInt('pin-length');
-  await prefs.setInt(PreferencesKey.currentPinLength, pinLength);
+
+  if (pinLength != null) {
+    await prefs.setInt(PreferencesKey.currentPinLength, pinLength);
+  }
 
   //default value for display list key?
   final walletName = await ios_legacy_helper.getString('current_wallet_name');
-  await prefs.setString('current_wallet_name', walletName);
+
+  if (walletName != null) {
+    await prefs.setString('current_wallet_name', walletName);
+  }
 
   await prefs.setInt('current_wallet_type', serializeToInt(WalletType.monero));
 
@@ -117,7 +138,13 @@ Future<void> ios_migrate_pin() async {
 
   final flutterSecureStorage = FlutterSecureStorage();
   final pinPassword = await flutterSecureStorage.read(
-      key: 'pin_password', iOptions: IOSOptions(syncFlag: "syna"));
+      key: 'pin_password', iOptions: IOSOptions());
+  // No pin
+  if (pinPassword == null) {
+    await prefs.setBool('ios_migration_pin_completed', true);
+    return;
+  }
+
   final key = generateStoreKeyFor(key: SecretStoreKey.pinCodePassword);
   final encodedPassword = encodedPinCode(pin: pinPassword);
   await flutterSecureStorage.write(key: key, value: encodedPassword);
@@ -148,9 +175,9 @@ Future<void> ios_migrate_wallet_passwords() async {
         final name = item.path.split('/').last;
         final oldKey = 'wallet_monero_' + name + '_password';
         final password = await flutterSecureStorage.read(
-            key: oldKey, iOptions: IOSOptions(syncFlag: "syna"));
+            key: oldKey, iOptions: IOSOptions());
         await keyService.saveWalletPassword(
-            walletName: name, password: password);
+            walletName: name, password: password!);
       }
     } catch (e) {
       print(e.toString());
@@ -197,14 +224,14 @@ FiatCurrency convertFiatLegacy(int raw) {
     32: 'zar',
     33: 'vef'
   };
-  final fiatAsString = _map[raw];
+  final fiatAsString = _map[raw]!;
 
   return FiatCurrency.deserialize(raw: fiatAsString.toUpperCase());
 }
 
-Future<void> android_migrate_hives({Directory appDocDir}) async {
+Future<void> android_migrate_hives({required Directory appDocDir}) async {
   final dbDir = Directory('${appDocDir.path}/db');
-  final files = List<File>();
+  final files = <File>[];
 
   appDocDir.listSync().forEach((FileSystemEntity item) {
     final ext = item.path.split('.').last;
@@ -225,10 +252,10 @@ Future<void> android_migrate_hives({Directory appDocDir}) async {
   });
 }
 
-Future<void> android_migrate_wallets({Directory appDocDir}) async {
+Future<void> android_migrate_wallets({required Directory appDocDir}) async {
   final walletsDir = Directory('${appDocDir.path}/wallets');
   final moneroWalletsDir = Directory('${walletsDir.path}/monero');
-  final dirs = List<Directory>();
+  final dirs = <Directory>[];
 
   appDocDir.listSync().forEach((FileSystemEntity item) {
     final name = item.path.split('/').last;
@@ -292,9 +319,8 @@ Future<void> ios_migrate_wallet_info(Box<WalletInfo> walletsInfoSource) async {
                   '_' +
                   name;
               final exist = walletsInfoSource.values
-                      .firstWhere((el) => el.id == id, orElse: () => null) !=
-                  null;
-
+                      .firstWhereOrNull((el) => el.id == id) != null;
+                      
               if (exist) {
                 return null;
               }
@@ -307,7 +333,8 @@ Future<void> ios_migrate_wallet_info(Box<WalletInfo> walletsInfoSource) async {
                   restoreHeight: 0,
                   date: date,
                   dirPath: item.path,
-                  path: '${item.path}/$name');
+                  path: '${item.path}/$name',
+                  address: '');
 
               return walletInfo;
             }
@@ -317,8 +344,8 @@ Future<void> ios_migrate_wallet_info(Box<WalletInfo> walletsInfoSource) async {
           }
         })
         .where((el) => el != null)
+        .whereType<WalletInfo>()
         .toList();
-    print(infoRecords);
     await walletsInfoSource.addAll(infoRecords);
     await prefs.setBool('ios_migration_wallet_info_completed', true);
   } catch (e) {
@@ -346,8 +373,8 @@ Future<void> ios_migrate_trades_list(Box<Trade> tradeSource) async {
     final content = file.readAsBytesSync();
     final flutterSecureStorage = FlutterSecureStorage();
     final masterPassword = await flutterSecureStorage.read(
-        key: 'master_password', iOptions: IOSOptions(syncFlag: "syna"));
-    final key = masterPassword.replaceAll('-', '');
+        key: 'master_password', iOptions: IOSOptions());
+    final key = masterPassword!.replaceAll('-', '');
     final decoded =
         await ios_legacy_helper.decrypt(content, key: key, salt: secrets.salt);
     final decodedJson = json.decode(decoded) as List<dynamic>;
@@ -362,7 +389,7 @@ Future<void> ios_migrate_trades_list(Box<Trade> tradeSource) async {
       final from = CryptoCurrency.fromString(fromAsString);
       final timestamp = dateAsDouble.toInt() * 1000;
       final date = DateTime.fromMillisecondsSinceEpoch(timestamp);
-      ExchangeProviderDescription provider;
+      ExchangeProviderDescription? provider;
 
       switch (providerAsString.toLowerCase()) {
         case 'changenow':
@@ -379,7 +406,7 @@ Future<void> ios_migrate_trades_list(Box<Trade> tradeSource) async {
       }
 
       return Trade(
-          id: tradeId, provider: provider, from: from, to: to, createdAt: date);
+          id: tradeId, provider: provider!, from: from, to: to, createdAt: date, amount: '');
     });
     await tradeSource.addAll(trades);
     await prefs.setBool('ios_migration_trade_list_completed', true);

lib/entities/get_encryption_key.dart

@@ -2,7 +2,7 @@ import 'package:flutter_secure_storage/flutter_secure_storage.dart';
 import 'package:hive/hive.dart';
 
 Future<List<int>> getEncryptionKey(
-    {String forKey, FlutterSecureStorage secureStorage}) async {
+    {required String forKey, required FlutterSecureStorage secureStorage}) async {
   final stringifiedKey =
       await secureStorage.read(key: 'transactionDescriptionsBoxKey');
   List<int> key;

lib/entities/ios_legacy_helper.dart

@@ -7,19 +7,19 @@ const platform =
     const MethodChannel('com.cakewallet.cakewallet/legacy_wallet_migration');
 
 Future<String> decrypt(Uint8List bytes,
-        {@required String key, @required String salt}) async =>
-    await platform
-        .invokeMethod('decrypt', {'bytes': bytes, 'key': key, 'salt': salt});
+        {required String key, required String salt}) async =>
+    (await platform
+        .invokeMethod<String>('decrypt', {'bytes': bytes, 'key': key, 'salt': salt}))!;
 
-Future<dynamic> readUserDefaults(String key, {@required String type}) async =>
+Future<dynamic> readUserDefaults(String key, {required String type}) async =>
     await platform
         .invokeMethod<dynamic>('read_user_defaults', {'key': key, 'type': type});
 
-Future<String> getString(String key) async =>
-    await readUserDefaults(key, type: 'string') as String;
+Future<String?> getString(String key) async =>
+    await readUserDefaults(key, type: 'string') as String?;
 
-Future<bool> getBool(String key) async =>
-    await readUserDefaults(key, type: 'bool') as bool;
+Future<bool?> getBool(String key) async =>
+    await readUserDefaults(key, type: 'bool') as bool?;
 
-Future<int> getInt(String key) async =>
-    await readUserDefaults(key, type: 'int') as int;
+Future<int?> getInt(String key) async =>
+    await readUserDefaults(key, type: 'int') as int?;

lib/entities/language_service.dart

@@ -50,7 +50,7 @@ class LanguageService {
   }
 
   static Future<String> localeDetection() async {
-    var locale = await Devicelocale.currentLocale;
+    var locale = await Devicelocale.currentLocale ?? '';
     locale = Intl.shortLocale(locale);
 
     return list.keys.contains(locale) ? locale : 'en';

lib/entities/load_current_wallet.dart

@@ -15,6 +15,11 @@ Future<void> loadCurrentWallet() async {
   final typeRaw =
       getIt.get<SharedPreferences>().getInt(PreferencesKey.currentWalletType) ??
           0;
+
+  if (name == null) {
+    throw Exception('Incorrect current wallet name: $name');
+  }
+
   final type = deserializeFromInt(typeRaw);
   final walletLoadingService = getIt.get<WalletLoadingService>();
   final wallet = await walletLoadingService.load(type, name);

lib/entities/mnemonic_item.dart

@@ -1,5 +1,5 @@
 class MnemonicItem {
-  MnemonicItem({String text}) : _text = text;
+  MnemonicItem({required String text}) : _text = text;
 
   String get text => _text;
   String _text;

lib/entities/node_list.dart

@@ -6,68 +6,68 @@ import 'package:cw_core/wallet_type.dart';
 
 Future<List<Node>> loadDefaultNodes() async {
   final nodesRaw = await rootBundle.loadString('assets/node_list.yml');
-  final nodes = loadYaml(nodesRaw) as YamlList;
+  final loadedNodes = loadYaml(nodesRaw) as YamlList;
+  final nodes = <Node>[];
 
-  return nodes.map((dynamic raw) {
+  for (final raw in loadedNodes) {
     if (raw is Map) {
-      final node = Node.fromMap(raw);
-      node?.type = WalletType.monero;
-
-      return node;
+      final node = Node.fromMap(raw as Map<String, Object>);
+      node.type = WalletType.monero;
+      nodes.add(node);
     }
+  }
 
-    return null;
-  }).toList();
+  return nodes;
 }
 
 Future<List<Node>> loadBitcoinElectrumServerList() async {
   final serverListRaw =
       await rootBundle.loadString('assets/bitcoin_electrum_server_list.yml');
-  final serverList = loadYaml(serverListRaw) as YamlList;
+  final loadedServerList = loadYaml(serverListRaw) as YamlList;
+  final serverList = <Node>[];
 
-  return serverList.map((dynamic raw) {
-    if (raw is Map) {
-      final node = Node.fromMap(raw);
-      node?.type = WalletType.bitcoin;
-
-      return node;
+  for (final raw in loadedServerList) {
+     if (raw is Map) {
+      final node = Node.fromMap(raw as Map<String, Object>);
+      node.type = WalletType.bitcoin;
+      serverList.add(node);
     }
+  }
 
-    return null;
-  }).toList();
+  return serverList;
 }
 
 Future<List<Node>> loadLitecoinElectrumServerList() async {
   final serverListRaw =
       await rootBundle.loadString('assets/litecoin_electrum_server_list.yml');
-  final serverList = loadYaml(serverListRaw) as YamlList;
+  final loadedServerList = loadYaml(serverListRaw) as YamlList;
+  final serverList = <Node>[];
 
-  return serverList.map((dynamic raw) {
+  for (final raw in loadedServerList) {
     if (raw is Map) {
-      final node = Node.fromMap(raw);
-      node?.type = WalletType.litecoin;
-
-      return node;
+      final node = Node.fromMap(raw as Map<String, Object>);
+      node.type = WalletType.litecoin;
+      serverList.add(node);
     }
+  }
 
-    return null;
-  }).toList();
+  return serverList;
 }
 
 Future<List<Node>> loadDefaultHavenNodes() async {
   final nodesRaw = await rootBundle.loadString('assets/haven_node_list.yml');
-  final nodes = loadYaml(nodesRaw) as YamlList;
+  final loadedNodes = loadYaml(nodesRaw) as YamlList;
+  final nodes = <Node>[];
 
-  return nodes.map((dynamic raw) {
+  for (final raw in loadedNodes) {
     if (raw is Map) {
-      final node = Node.fromMap(raw);
-      node?.type = WalletType.haven;
-
-      return node;
+      final node = Node.fromMap(raw as Map<String, Object>);
+      node.type = WalletType.haven;
+      nodes.add(node);
     }
-
-    return null;
-  }).toList();
+  }
+  
+  return nodes;
 }
 
 Future resetToDefault(Box<Node> nodeSource) async {

lib/entities/openalias_record.dart

@@ -1,12 +1,11 @@
 import 'package:basic_utils/basic_utils.dart';
 import 'package:cw_core/wallet_type.dart';
-import 'package:flutter/material.dart';
 
 class OpenaliasRecord {
   OpenaliasRecord({
-    this.address,
-    this.name,
-    this.description,
+    required this.address,
+    required this.name,
+    required this.description,
   });
 
   final String name;
@@ -24,8 +23,8 @@ class OpenaliasRecord {
   }
 
   static Future<OpenaliasRecord> fetchAddressAndName({
-    @required String formattedName,
-    @required String ticker,
+    required String formattedName,
+    required String ticker,
   }) async {
     String address = formattedName;
     String name = formattedName;

lib/entities/parse_address_from_domain.dart

@@ -9,7 +9,7 @@ import 'package:cake_wallet/entities/fio_address_provider.dart';
 
 class AddressResolver {
   
-  AddressResolver({@required this.yatService, this.walletType});
+  AddressResolver({required this.yatService, required this.walletType});
   
   final YatService yatService;
   final WalletType walletType;

lib/entities/parsed_address.dart

@@ -6,47 +6,42 @@ enum ParseFrom { unstoppableDomains, openAlias, yatRecord, fio, notParsed }
 
 class ParsedAddress {
   ParsedAddress({
-    this.addresses,
+    required this.addresses,
     this.name = '',
     this.description = '',
     this.parseFrom = ParseFrom.notParsed,
   });
-
-  final List<String> addresses;
-  final String name;
-  final String description;
-  final ParseFrom parseFrom;
   
   factory ParsedAddress.fetchEmojiAddress({
-    @required List<YatRecord> addresses, 
-    @required String name,
+    List<YatRecord>? addresses, 
+    required String name,
     }){
       if (addresses?.isEmpty ?? true) {
         return ParsedAddress(
           addresses: [name], parseFrom: ParseFrom.yatRecord);
-        }
+      }
       return ParsedAddress(
-        addresses: addresses.map((e) => e.address).toList(),
+        addresses: addresses!.map((e) => e.address).toList(),
         name: name,
         parseFrom: ParseFrom.yatRecord,
       );
   }
 
   factory ParsedAddress.fetchUnstoppableDomainAddress({
-    @required String address, 
-    @required String name,
+    String? address, 
+    required String name,
   }){
-    if (address?.isEmpty ?? true) {
+      if (address?.isEmpty ?? true) {
         return ParsedAddress(addresses: [name]);
       }
       return ParsedAddress(
-        addresses: [address],
+        addresses: [address!],
         name: name,
         parseFrom: ParseFrom.unstoppableDomains,
       );
   }
 
-  factory ParsedAddress.fetchOpenAliasAddress({@required OpenaliasRecord record, @required String name}){
+  factory ParsedAddress.fetchOpenAliasAddress({OpenaliasRecord? record, required String name}){
     final formattedName = OpenaliasRecord.formatDomainName(name);
     if (record == null || record.address.contains(formattedName)) {
         return ParsedAddress(addresses: [name]);
@@ -59,12 +54,16 @@ class ParsedAddress {
       );
   }
 
-  factory ParsedAddress.fetchFioAddress({@required String address, @required String name}){
-
+  factory ParsedAddress.fetchFioAddress({required String address, required String name}){
     return ParsedAddress(
       addresses: [address],
       name: name,
       parseFrom: ParseFrom.fio,
     );
   }
+
+  final List<String> addresses;
+  final String name;
+  final String description;
+  final ParseFrom parseFrom;
 }

lib/entities/qr_scanner.dart

@@ -1,15 +1,17 @@
-import 'package:barcode_scan/barcode_scan.dart';
+// import 'package:barcode_scan/barcode_scan.dart';
 
 var isQrScannerShown = false;
 
 Future<String> presentQRScanner() async {
   isQrScannerShown = true;
-  try {
-    final result = await BarcodeScanner.scan();
-    isQrScannerShown = false;
-    return result.rawContent;
-  } catch (e) {
-    isQrScannerShown = false;
-    rethrow;
-  }
+  // FIX-ME: BarcodeScanner
+  throw Exception('Unimplemented');
+  // try {
+  //   final result = await BarcodeScanner.scan();
+  //   isQrScannerShown = false;
+  //   return result.rawContent;
+  // } catch (e) {
+  //   isQrScannerShown = false;
+  //   rethrow;
+  // }
 }

lib/entities/record.dart

@@ -27,7 +27,7 @@ abstract class Record<T extends HiveObject> with Keyable {
 
   final Box<T> _source;
 
-  StreamSubscription<BoxEvent> _listener;
+  StreamSubscription<BoxEvent>? _listener;
 
   void fromBind(T original);
 

lib/entities/secret_store_key.dart

@@ -5,7 +5,7 @@ const pinCodePassword = "PIN_CODE_PASSWORD";
 const backupPassword = "BACKUP_CODE_PASSWORD";
 
 String generateStoreKeyFor({
-  SecretStoreKey key,
+  required SecretStoreKey key,
   String walletName = "",
 }) {
   var _key = "";

lib/entities/template.dart

@@ -4,7 +4,14 @@ part 'template.g.dart';
 
 @HiveType(typeId: Template.typeId)
 class Template extends HiveObject {
-  Template({this.name,this.isCurrencySelected, this.address, this.cryptoCurrency, this.amount, this.fiatCurrency, this.amountFiat});
+  Template({
+    required this.name,
+    required this.isCurrencySelected,
+    required this.address,
+    required this.cryptoCurrency,
+    required this.amount,
+    required this.fiatCurrency,
+    required this.amountFiat});
 
   static const typeId = 6;
   static const boxName = 'Template';

lib/entities/transaction_description.dart

@@ -4,7 +4,7 @@ part 'transaction_description.g.dart';
 
 @HiveType(typeId: TransactionDescription.typeId)
 class TransactionDescription extends HiveObject {
-  TransactionDescription({this.id, this.recipientAddress, this.transactionNote});
+  TransactionDescription({required this.id, this.recipientAddress, this.transactionNote});
 
   static const typeId = 2;
   static const boxName = 'TransactionDescriptions';
@@ -14,10 +14,10 @@ class TransactionDescription extends HiveObject {
   String id;
 
   @HiveField(1)
-  String recipientAddress;
+  String? recipientAddress;
 
   @HiveField(2)
-  String transactionNote;
+  String? transactionNote;
 
   String get note => transactionNote ?? '';
 }

lib/entities/transaction_history.dart

@@ -2,6 +2,9 @@ import 'package:mobx/mobx.dart';
 import 'package:cw_core/transaction_info.dart';
 
 abstract class TransactionHistory {
+  TransactionHistory()
+    : transactions = Observable<List<TransactionInfo>>([]);
+
   Observable<List<TransactionInfo>> transactions;
   Future<List<TransactionInfo>> getAll();
   Future update();

lib/entities/unstoppable_domain_address.dart

@@ -6,13 +6,13 @@ Future<String> fetchUnstoppableDomainAddress(String domain, String ticker) async
   var address = '';
 
   try {
-    address = await channel.invokeMethod(
+    address = await channel.invokeMethod<String>(
         'getUnstoppableDomainAddress',
         <String, String> {
           'domain' : domain,
           'ticker' : ticker
         }
-    );
+    ) ?? '';
   } catch (e) {
     print('Unstoppable domain error: ${e.toString()}');
     address = '';

lib/entities/update_haven_rate.dart

@@ -4,18 +4,23 @@ import 'package:cw_core/monero_amount_format.dart';
 import 'package:cake_wallet/haven/haven.dart';
 
 Future<void> updateHavenRate(FiatConversionStore fiatConversionStore) async {
-  final rate = haven.getAssetRate();
-  final base = rate.firstWhere((row) => row.asset == 'XUSD', orElse: () => null);
-  rate.forEach((row) {
-    final cur = CryptoCurrency.fromString(row.asset);
-    final baseRate = moneroAmountToDouble(amount: base.rate);
-    final rowRate = moneroAmountToDouble(amount: row.rate);
+  try {
+    final rate = haven!.getAssetRate();
+    final base = rate.firstWhere((row) => row.asset == 'XUSD');
 
-    if (cur == CryptoCurrency.xusd) {
-      fiatConversionStore.prices[cur] = 1.0;
-      return;
-    }
+    rate.forEach((row) {
+      final cur = CryptoCurrency.fromString(row.asset);
+      final baseRate = moneroAmountToDouble(amount: base.rate);
+      final rowRate = moneroAmountToDouble(amount: row.rate);
 
-    fiatConversionStore.prices[cur] = baseRate / rowRate;
-  });
+      if (cur == CryptoCurrency.xusd) {
+        fiatConversionStore.prices[cur] = 1.0;
+        return;
+      }
+
+      fiatConversionStore.prices[cur] = baseRate / rowRate;
+    });
+  } catch(_) {
+    // FIX-ME: handle exception    
+  }
 }

lib/entities/wallet_contact.dart

@@ -3,6 +3,7 @@ import 'package:cw_core/crypto_currency.dart';
 
 class WalletContact implements ContactBase {
   WalletContact(this.address, this.name, this.type);
+    //: super(name, address, type);
 
   @override
   String address;

lib/entities/wallet_description.dart

@@ -1,7 +1,7 @@
 import 'package:cw_core/wallet_type.dart';
 
 class WalletDescription {
-  WalletDescription({this.name, this.type});
+  WalletDescription({required this.name, required this.type});
   
   final String name;
   final WalletType type;

lib/entities/yat_record.dart

@@ -1,16 +1,13 @@
 class YatRecord {
-  String category;
-  String address;
-
   YatRecord({
-    this.category,
-    this.address,
+    required this.category,
+    required this.address,
   });
 
-  YatRecord.fromJson(Map<String, dynamic> json) {
-    address = json['address'] as String;
-    category = json['category'] as String;
-  }
+  YatRecord.fromJson(Map<String, dynamic> json)
+    : address = json['address'] as String,
+      category = json['category'] as String;
 
-  
+  String category;
+  String address; 
 }

lib/exchange/changenow/changenow_exchange_provider.dart

@@ -1,6 +1,5 @@
 import 'dart:convert';
 import 'package:cake_wallet/exchange/trade_not_found_exeption.dart';
-import 'package:flutter/foundation.dart';
 import 'package:http/http.dart';
 import 'package:cake_wallet/.secrets.g.dart' as secrets;
 import 'package:cw_core/crypto_currency.dart';
@@ -56,8 +55,10 @@ class ChangeNowExchangeProvider extends ExchangeProvider {
   static String getFlow(bool isFixedRate) => isFixedRate ? 'fixed-rate' : 'standard';
 
   @override
-  Future<Limits> fetchLimits({CryptoCurrency from, CryptoCurrency to,
-    bool isFixedRateMode}) async {
+  Future<Limits> fetchLimits({
+    required CryptoCurrency from,
+    required CryptoCurrency to,
+    required bool isFixedRateMode}) async {
     final headers = {apiHeaderKey: apiKey};
     final normalizedFrom = normalizeCryptoCurrency(from);
     final normalizedTo = normalizeCryptoCurrency(to);
@@ -79,7 +80,7 @@ class ChangeNowExchangeProvider extends ExchangeProvider {
     }
 
     if (response.statusCode != 200) {
-      return null;
+      throw Exception('Unexpected http status: ${response.statusCode}');
     }
 
     final responseJSON = json.decode(response.body) as Map<String, dynamic>;
@@ -89,7 +90,7 @@ class ChangeNowExchangeProvider extends ExchangeProvider {
   }
 
   @override
-  Future<Trade> createTrade({TradeRequest request, bool isFixedRateMode}) async {
+  Future<Trade> createTrade({required TradeRequest request, required bool isFixedRateMode}) async {
     final _request = request as ChangeNowRequest;
     final headers = {
       apiHeaderKey: apiKey,
@@ -122,7 +123,7 @@ class ChangeNowExchangeProvider extends ExchangeProvider {
     }
 
     if (response.statusCode != 200) {
-      return null;
+      throw Exception('Unexpected http status: ${response.statusCode}');
     }
 
     final responseJSON = json.decode(response.body) as Map<String, dynamic>;
@@ -145,7 +146,7 @@ class ChangeNowExchangeProvider extends ExchangeProvider {
   }
 
   @override
-  Future<Trade> findTradeById({@required String id}) async {
+  Future<Trade> findTradeById({required String id}) async {
     final headers = {apiHeaderKey: apiKey};
     final params = <String, String>{'id': id};
     final uri = Uri.https(apiAuthority,findTradeByIdPath, params);
@@ -164,7 +165,7 @@ class ChangeNowExchangeProvider extends ExchangeProvider {
     }
 
     if (response.statusCode != 200) {
-      return null;
+      throw Exception('Unexpected http status: ${response.statusCode}');
     }
 
     final responseJSON = json.decode(response.body) as Map<String, dynamic>;
@@ -198,11 +199,11 @@ class ChangeNowExchangeProvider extends ExchangeProvider {
 
   @override
   Future<double> calculateAmount(
-      {CryptoCurrency from,
-      CryptoCurrency to,
-      double amount,
-      bool isFixedRateMode,
-      bool isReceiveAmount}) async {
+      {required CryptoCurrency from,
+      required CryptoCurrency to,
+      required double amount,
+      required bool isFixedRateMode,
+      required bool isReceiveAmount}) async {
     try {
       if (amount == 0) {
         return 0.0;
@@ -250,7 +251,7 @@ class ChangeNowExchangeProvider extends ExchangeProvider {
         return CryptoCurrency.btc.title.toLowerCase();
       default:
         return currency.tag != null
-            ? currency.tag.toLowerCase()
+            ? currency.tag!.toLowerCase()
             : currency.title.toLowerCase();
       }
     }

lib/exchange/changenow/changenow_request.dart

@@ -4,13 +4,13 @@ import 'package:cake_wallet/exchange/trade_request.dart';
 
 class ChangeNowRequest extends TradeRequest {
   ChangeNowRequest(
-      {@required this.from,
-      @required this.to,
-      @required this.address,
-      @required this.fromAmount,
-      @required this.toAmount,
-      @required this.refundAddress,
-      @required this.isReverse});
+      {required this.from,
+      required this.to,
+      required this.address,
+      required this.fromAmount,
+      required this.toAmount,
+      required this.refundAddress,
+      required this.isReverse});
 
   CryptoCurrency from;
   CryptoCurrency to;

lib/exchange/exchange_pair.dart

@@ -1,7 +1,10 @@
 import 'package:cw_core/crypto_currency.dart';
 
 class ExchangePair {
-  ExchangePair({this.from, this.to, this.reverse = true});
+  ExchangePair({
+    required this.from,
+    required this.to,
+    this.reverse = true});
 
   final CryptoCurrency from;
   final CryptoCurrency to;

lib/exchange/exchange_provider.dart

@@ -7,11 +7,11 @@ import 'package:cake_wallet/exchange/trade.dart';
 import 'package:cake_wallet/exchange/exchange_provider_description.dart';
 
 abstract class ExchangeProvider {
-  ExchangeProvider({this.pairList});
+  ExchangeProvider({required this.pairList});
   
   String get title;
   List<ExchangePair> pairList;
-  ExchangeProviderDescription description;
+  ExchangeProviderDescription get description;
   bool get isAvailable;
   bool get isEnabled;
 
@@ -19,10 +19,18 @@ abstract class ExchangeProvider {
   String toString() => title;
 
   Future<Limits> fetchLimits(
-      {CryptoCurrency from, CryptoCurrency to, bool isFixedRateMode});
-  Future<Trade> createTrade({TradeRequest request, bool isFixedRateMode});
-  Future<Trade> findTradeById({@required String id});
-  Future<double> calculateAmount({CryptoCurrency from, CryptoCurrency to,
-    double amount, bool isFixedRateMode, bool isReceiveAmount});
+      {required CryptoCurrency from,
+      required CryptoCurrency to,
+      required bool isFixedRateMode});
+  Future<Trade> createTrade({
+    required TradeRequest request,
+    required bool isFixedRateMode});
+  Future<Trade> findTradeById({required String id});
+  Future<double> calculateAmount({
+    required CryptoCurrency from,
+    required CryptoCurrency to,
+    required double amount,
+    required bool isFixedRateMode,
+    required bool isReceiveAmount});
   Future<bool> checkIsAvailable();
 }

lib/exchange/exchange_provider_description.dart

@@ -2,7 +2,11 @@ import 'package:cw_core/enumerable_item.dart';
 
 class ExchangeProviderDescription extends EnumerableItem<int>
     with Serializable<int> {
-  const ExchangeProviderDescription({String title, int raw, this.horizontalLogo = false, this.image})
+  const ExchangeProviderDescription({
+    required String title,
+    required int raw,
+    required this.image,
+    this.horizontalLogo = false})
       : super(title: title, raw: raw);
 
   final bool horizontalLogo;
@@ -20,7 +24,7 @@ class ExchangeProviderDescription extends EnumerableItem<int>
   static const simpleSwap =
       ExchangeProviderDescription(title: 'SimpleSwap', raw: 4, image: 'assets/images/simpleSwap.png');
 
-  static ExchangeProviderDescription deserialize({int raw}) {
+  static ExchangeProviderDescription deserialize({required int raw}) {
     switch (raw) {
       case 0:
         return xmrto;
@@ -33,7 +37,7 @@ class ExchangeProviderDescription extends EnumerableItem<int>
       case 4:
         return simpleSwap;
       default:
-        return null;
+        throw Exception('Unexpected token: $raw for ExchangeProviderDescription deserialize');
     }
   }
 }

lib/exchange/exchange_template.dart

@@ -5,12 +5,12 @@ part 'exchange_template.g.dart';
 @HiveType(typeId: ExchangeTemplate.typeId)
 class ExchangeTemplate extends HiveObject {
   ExchangeTemplate({
-    this.amount,
-    this.depositCurrency,
-    this.receiveCurrency,
-    this.provider,
-    this.depositAddress,
-    this.receiveAddress
+    required this.amount,
+    required this.depositCurrency,
+    required this.receiveCurrency,
+    required this.provider,
+    required this.depositAddress,
+    required this.receiveAddress
   });
 
   static const typeId = 7;

lib/exchange/exchange_trade_state.dart

@@ -8,13 +8,13 @@ class ExchangeTradeStateInitial extends ExchangeTradeState {}
 class TradeIsCreating extends ExchangeTradeState {}
 
 class TradeIsCreatedSuccessfully extends ExchangeTradeState {
-  TradeIsCreatedSuccessfully({@required this.trade});
+  TradeIsCreatedSuccessfully({required this.trade});
 
   final Trade trade;
 }
 
 class TradeIsCreatedFailure extends ExchangeTradeState {
-  TradeIsCreatedFailure({@required this.title, @required this.error});
+  TradeIsCreatedFailure({required this.title, required this.error});
 
   final String title;
   final String error;

lib/exchange/limits.dart

@@ -1,6 +1,6 @@
 class Limits {
   const Limits({this.min, this.max});
   
-  final double min;
-  final double max;
+  final double? min;
+  final double? max;
 }

lib/exchange/limits_state.dart

@@ -8,13 +8,13 @@ class LimitsInitialState extends LimitsState {}
 class LimitsIsLoading extends LimitsState {}
 
 class LimitsLoadedSuccessfully extends LimitsState {
-  LimitsLoadedSuccessfully({@required this.limits});
+  LimitsLoadedSuccessfully({required this.limits});
 
   final Limits limits;
 }
 
 class LimitsLoadedFailure extends LimitsState {
-  LimitsLoadedFailure({@required this.error});
+  LimitsLoadedFailure({required this.error});
 
   final String error;
 }

lib/exchange/morphtoken/morphtoken_exchange_provider.dart

@@ -16,7 +16,7 @@ import 'package:cake_wallet/exchange/exchange_provider_description.dart';
 import 'package:cake_wallet/exchange/trade_not_created_exeption.dart';
 
 class MorphTokenExchangeProvider extends ExchangeProvider {
-  MorphTokenExchangeProvider({@required this.trades})
+  MorphTokenExchangeProvider({required this.trades})
       : super(pairList: [
           ExchangePair(from: CryptoCurrency.xmr, to: CryptoCurrency.eth),
           ExchangePair(from: CryptoCurrency.xmr, to: CryptoCurrency.bch),
@@ -74,8 +74,12 @@ class MorphTokenExchangeProvider extends ExchangeProvider {
   Future<bool> checkIsAvailable() async => true;
 
   @override
-  Future<Limits> fetchLimits({CryptoCurrency from, CryptoCurrency to, bool isFixedRateMode}) async {
+  Future<Limits> fetchLimits({
+    required CryptoCurrency from,
+    required CryptoCurrency to,
+    required bool isFixedRateMode}) async {
     final url = apiUri + _limitsURISuffix;
+    final uri = Uri.parse(url);
     final headers = {'Content-type': 'application/json'};
     final body = json.encode({
       "input": {"asset": from.toString()},
@@ -83,11 +87,11 @@ class MorphTokenExchangeProvider extends ExchangeProvider {
         {"asset": to.toString(), "weight": weight}
       ]
     });
-    final response = await post(url, headers: headers, body: body);
+    final response = await post(uri, headers: headers, body: body);
     final responseJSON = json.decode(response.body) as Map<String, dynamic>;
 
     final min = responseJSON['input']['limits']['min'] as int;
-    int max;
+    int max = 0;
     double ethMax;
 
     if (from == CryptoCurrency.eth) {
@@ -96,14 +100,16 @@ class MorphTokenExchangeProvider extends ExchangeProvider {
       max = responseJSON['input']['limits']['max'] as int;
     }
 
-    double minFormatted = AmountConverter.amountIntToDouble(from, min);
-    double maxFormatted = AmountConverter.amountIntToDouble(from, max);
+    final minFormatted = AmountConverter.amountIntToDouble(from, min);
+    final maxFormatted = AmountConverter.amountIntToDouble(from, max);
 
     return Limits(min: minFormatted, max: maxFormatted);
   }
 
   @override
-  Future<Trade> createTrade({TradeRequest request, bool isFixedRateMode}) async {
+  Future<Trade> createTrade({
+    required TradeRequest request,
+    required bool isFixedRateMode}) async {
     const url = apiUri + _morphURISuffix;
     final _request = request as MorphTokenRequest;
     final body = {
@@ -120,8 +126,8 @@ class MorphTokenExchangeProvider extends ExchangeProvider {
       ],
       "tag": "cakewallet"
     };
-
-    final response = await post(url,
+    final uri = Uri.parse(url);
+    final response = await post(uri,
         headers: {'Content-Type': 'application/json'}, body: json.encode(body));
 
     if (response.statusCode != 200) {
@@ -149,9 +155,10 @@ class MorphTokenExchangeProvider extends ExchangeProvider {
   }
 
   @override
-  Future<Trade> findTradeById({@required String id}) async {
+  Future<Trade> findTradeById({required String id}) async {
     final url = apiUri + _morphURISuffix + '/' + id;
-    final response = await get(url);
+    final uri = Uri.parse(url);
+    final response = await get(uri);
 
     if (response.statusCode != 200) {
       if (response.statusCode == 400) {
@@ -194,17 +201,21 @@ class MorphTokenExchangeProvider extends ExchangeProvider {
 
   @override
   Future<double> calculateAmount(
-      {CryptoCurrency from, CryptoCurrency to, double amount, bool isFixedRateMode,
-        bool isReceiveAmount}) async {
+      {required CryptoCurrency from,
+      required CryptoCurrency to,
+      required double amount,
+      required bool isFixedRateMode,
+      required bool isReceiveAmount}) async {
     final url = apiUri + _ratesURISuffix;
-    final response = await get(url);
+    final uri = Uri.parse(url);
+    final response = await get(uri);
     final responseJSON = json.decode(response.body) as Map<String, dynamic>;
     final rate = responseJSON['data'][from.toString()][to.toString()] as String;
 
     try {
       final estimatedAmount = double.parse(rate) * amount;
       return estimatedAmount;
-    } catch (e) {
+    } catch (_) {
       return 0.0;
     }
   }

lib/exchange/morphtoken/morphtoken_request.dart

@@ -4,11 +4,11 @@ import 'package:cake_wallet/exchange/trade_request.dart';
 
 class MorphTokenRequest extends TradeRequest {
   MorphTokenRequest(
-      {@required this.from,
-        @required this.to,
-        @required this.address,
-        @required this.amount,
-        @required this.refundAddress});
+      {required this.from,
+        required this.to,
+        required this.address,
+        required this.amount,
+        required this.refundAddress});
 
   CryptoCurrency from;
   CryptoCurrency to;

lib/exchange/sideshift/sideshift_exchange_provider.dart

@@ -40,11 +40,11 @@ class SideShiftExchangeProvider extends ExchangeProvider {
 
   @override
   Future<double> calculateAmount(
-      {CryptoCurrency from,
-      CryptoCurrency to,
-      double amount,
-      bool isFixedRateMode,
-      bool isReceiveAmount}) async {
+      {required CryptoCurrency from,
+      required CryptoCurrency to,
+      required double amount,
+      required bool isFixedRateMode,
+      required bool isReceiveAmount}) async {
     try {
       if (amount == 0) {
         return 0.0;
@@ -53,7 +53,8 @@ class SideShiftExchangeProvider extends ExchangeProvider {
       final toCurrency = _normalizeCryptoCurrency(to);
       final url =
           apiBaseUrl + rangePath + '/' + fromCurrency + '/' + toCurrency;
-      final response = await get(url);
+      final uri = Uri.parse(url);
+      final response = await get(uri);
       final responseJSON = json.decode(response.body) as Map<String, dynamic>;
       final rate = double.parse(responseJSON['rate'] as String);
       final max = double.parse(responseJSON['max'] as String);
@@ -71,7 +72,8 @@ class SideShiftExchangeProvider extends ExchangeProvider {
   @override
   Future<bool> checkIsAvailable() async {
     const url = apiBaseUrl + permissionPath;
-    final response = await get(url);
+    final uri = Uri.parse(url);
+    final response = await get(uri);
 
     if (response.statusCode == 500) {
       final responseJSON = json.decode(response.body) as Map<String, dynamic>;
@@ -92,7 +94,7 @@ class SideShiftExchangeProvider extends ExchangeProvider {
 
   @override
   Future<Trade> createTrade(
-      {TradeRequest request, bool isFixedRateMode}) async {
+      {required TradeRequest request, required bool isFixedRateMode}) async {
     final _request = request as SideShiftRequest;
     final quoteId = await _createQuote(_request);
     final url = apiBaseUrl + orderPath;
@@ -104,7 +106,8 @@ class SideShiftExchangeProvider extends ExchangeProvider {
       'settleAddress': _request.settleAddress,
       'refundAddress': _request.refundAddress
     };
-    final response = await post(url, headers: headers, body: json.encode(body));
+    final uri = Uri.parse(url);
+    final response = await post(uri, headers: headers, body: json.encode(body));
 
     if (response.statusCode != 201) {
       if (response.statusCode == 400) {
@@ -146,7 +149,8 @@ class SideShiftExchangeProvider extends ExchangeProvider {
       'affiliateId': affiliateId,
       'depositAmount': request.depositAmount,
     };
-    final response = await post(url, headers: headers, body: json.encode(body));
+    final uri = Uri.parse(url);
+    final response = await post(uri, headers: headers, body: json.encode(body));
 
     if (response.statusCode != 201) {
       if (response.statusCode == 400) {
@@ -167,11 +171,14 @@ class SideShiftExchangeProvider extends ExchangeProvider {
 
   @override
   Future<Limits> fetchLimits(
-      {CryptoCurrency from, CryptoCurrency to, bool isFixedRateMode}) async {
+      {required CryptoCurrency from,
+      required CryptoCurrency to,
+      required bool isFixedRateMode}) async {
     final fromCurrency = _normalizeCryptoCurrency(from);
     final toCurrency = _normalizeCryptoCurrency(to);
     final url = apiBaseUrl + rangePath + '/' + fromCurrency + '/' + toCurrency;
-    final response = await get(url);
+    final uri = Uri.parse(url);
+    final response = await get(uri);
 
     if (response.statusCode == 500) {
       final responseJSON = json.decode(response.body) as Map<String, dynamic>;
@@ -181,7 +188,7 @@ class SideShiftExchangeProvider extends ExchangeProvider {
     }
 
     if (response.statusCode != 200) {
-      return null;
+      throw Exception('Unexpected http status: ${response.statusCode}');
     }
 
     final responseJSON = json.decode(response.body) as Map<String, dynamic>;
@@ -192,9 +199,10 @@ class SideShiftExchangeProvider extends ExchangeProvider {
   }
 
   @override
-  Future<Trade> findTradeById({@required String id}) async {
+  Future<Trade> findTradeById({required String id}) async {
     final url = apiBaseUrl + orderPath + '/' + id;
-    final response = await get(url);
+    final uri = Uri.parse(url);
+    final response = await get(uri);
 
     if (response.statusCode == 404) {
       throw TradeNotFoundException(id, provider: description);
@@ -209,7 +217,7 @@ class SideShiftExchangeProvider extends ExchangeProvider {
     }
 
     if (response.statusCode != 200) {
-      return null;
+      throw Exception('Unexpected http status: ${response.statusCode}');
     }
 
     final responseJSON = json.decode(response.body) as Map<String, dynamic>;
@@ -219,8 +227,8 @@ class SideShiftExchangeProvider extends ExchangeProvider {
     final to = CryptoCurrency.fromString(toCurrency);
     final inputAddress = responseJSON['depositAddress']['address'] as String;
     final expectedSendAmount = responseJSON['depositAmount'].toString();
-    final deposits = responseJSON['deposits'] as List;
-    TradeState state;
+    final deposits = responseJSON['deposits'] as List?;
+    TradeState? state;
 
     if (deposits != null && deposits.isNotEmpty) {
       final status = deposits[0]['status'] as String;
@@ -259,7 +267,7 @@ class SideShiftExchangeProvider extends ExchangeProvider {
       case CryptoCurrency.zec:
         return 'zec';
       case CryptoCurrency.bnb:
-        return currency.tag.toLowerCase();
+        return currency.tag!.toLowerCase();
       case CryptoCurrency.usdterc20:
         return 'usdtErc20';
       default:

lib/exchange/sideshift/sideshift_request.dart

@@ -2,16 +2,16 @@ import 'package:cake_wallet/exchange/trade_request.dart';
 import 'package:cw_core/crypto_currency.dart';
 
 class SideShiftRequest extends TradeRequest {
+  SideShiftRequest(
+      {required this.depositMethod,
+      required this.settleMethod,
+      required this.depositAmount,
+      required this.settleAddress,
+      required this.refundAddress});
+
   final CryptoCurrency depositMethod;
   final CryptoCurrency settleMethod;
   final String depositAmount;
   final String settleAddress;
   final String refundAddress;
-
-  SideShiftRequest(
-      {this.depositMethod,
-      this.settleMethod,
-      this.depositAmount,
-      this.settleAddress,
-      this.refundAddress,});
 }

lib/exchange/simpleswap/simpleswap_exchange_provider.dart

@@ -1,5 +1,4 @@
 import 'dart:convert';
-
 import 'package:cake_wallet/exchange/exchange_pair.dart';
 import 'package:cake_wallet/exchange/exchange_provider.dart';
 import 'package:cake_wallet/exchange/exchange_provider_description.dart';
@@ -36,7 +35,11 @@ class SimpleSwapExchangeProvider extends ExchangeProvider {
       
   @override
   Future<double> calculateAmount(
-      {CryptoCurrency from, CryptoCurrency to, double amount, bool isFixedRateMode, bool isReceiveAmount}) async {
+      {required CryptoCurrency from,
+      required CryptoCurrency to,
+      required double amount,
+      required bool isFixedRateMode,
+      required bool isReceiveAmount}) async {
     try {
       if (amount == 0) {
         return 0.0;
@@ -51,7 +54,6 @@ class SimpleSwapExchangeProvider extends ExchangeProvider {
         'fixed': isFixedRateMode.toString()
       };
       final uri = Uri.https(apiAuthority, getEstimatePath, params);
-      
       final response = await get(uri);
 
       if (response.body == null) return 0.00;
@@ -68,11 +70,11 @@ class SimpleSwapExchangeProvider extends ExchangeProvider {
     final uri = Uri.https(apiAuthority, getEstimatePath, <String, String>{'api_key': apiKey});
     final response = await get(uri);
 
-   return !(response.statusCode == 403);
+    return !(response.statusCode == 403);
   }
 
   @override
-  Future<Trade> createTrade({TradeRequest request, bool isFixedRateMode}) async {
+  Future<Trade> createTrade({required TradeRequest request, required bool isFixedRateMode}) async {
     final _request = request as SimpleSwapRequest;
     final headers = {
       'Content-Type': 'application/json'};
@@ -121,7 +123,10 @@ class SimpleSwapExchangeProvider extends ExchangeProvider {
   }
 
   @override
-  Future<Limits> fetchLimits({CryptoCurrency from, CryptoCurrency to, bool isFixedRateMode}) async {
+  Future<Limits> fetchLimits({
+    required CryptoCurrency from,
+    required CryptoCurrency to,
+    required bool isFixedRateMode}) async {
     final fromCurrency = _normalizeCryptoCurrency(from);
     final toCurrency = _normalizeCryptoCurrency(to);
     final params = <String, dynamic>{
@@ -142,7 +147,7 @@ class SimpleSwapExchangeProvider extends ExchangeProvider {
     }
 
     if (response.statusCode != 200) {
-      return null;
+      throw Exception('Unexpected http status: ${response.statusCode}');
     }
 
     final responseJSON = json.decode(response.body) as Map<String, dynamic>;
@@ -153,7 +158,7 @@ class SimpleSwapExchangeProvider extends ExchangeProvider {
   }
 
   @override
-  Future<Trade> findTradeById({String id}) async {
+  Future<Trade> findTradeById({required String id}) async {
     final params = {'api_key': apiKey, 'id': id};
     final uri = Uri.https(apiAuthority, getExchangePath, params);
     final response = await get(uri);
@@ -170,7 +175,7 @@ class SimpleSwapExchangeProvider extends ExchangeProvider {
     }
 
     if (response.statusCode != 200) {
-      return null;
+      throw Exception('Unexpected http status: ${response.statusCode}');
     }
 
     final responseJSON = json.decode(response.body) as Map<String, dynamic>;
@@ -210,7 +215,7 @@ class SimpleSwapExchangeProvider extends ExchangeProvider {
       case CryptoCurrency.zec:
         return 'zec';
       case CryptoCurrency.bnb:
-        return currency.tag.toLowerCase();
+        return currency.tag!.toLowerCase();
       case CryptoCurrency.usdterc20:
         return 'usdterc';
       default:

lib/exchange/simpleswap/simpleswap_request.dart

@@ -4,11 +4,12 @@ import 'package:flutter/material.dart';
 
 class SimpleSwapRequest extends TradeRequest {
   SimpleSwapRequest({
-    @required this.from,
-    @required this.to,
-    @required this.address,
-    @required this.amount,
-    @required this.refundAddress,
+    required this.from,
+    required this.to,
+    required this.address,
+    required this.amount,
+    required this.refundAddress,
+    this.toAmount = ''
   });
 
   CryptoCurrency from;

lib/exchange/trade.dart

@@ -9,23 +9,32 @@ part 'trade.g.dart';
 @HiveType(typeId: Trade.typeId)
 class Trade extends HiveObject {
   Trade(
-      {this.id,
-      ExchangeProviderDescription provider,
-      CryptoCurrency from,
-      CryptoCurrency to,
-      TradeState state,
+      {required this.id,
+      required this.amount,
+      ExchangeProviderDescription? provider,
+      CryptoCurrency? from,
+      CryptoCurrency? to,
+      TradeState? state,
       this.createdAt,
       this.expiredAt,
-      this.amount,
       this.inputAddress,
       this.extraId,
       this.outputTransaction,
       this.refundAddress,
-      this.walletId})
-      : providerRaw = provider?.raw,
-        fromRaw = from?.raw,
-        toRaw = to?.raw,
-        stateRaw = state?.raw;
+      this.walletId}) {
+    if (provider != null) {
+      providerRaw = provider.raw;
+    }
+    if (from != null) {
+      fromRaw = from.raw;
+    }
+    if (to != null) {
+      toRaw = to.raw;
+    }
+    if (state != null) {
+      stateRaw = state.raw;
+    }
+  }
 
   static const typeId = 3;
   static const boxName = 'Trades';
@@ -35,51 +44,51 @@ class Trade extends HiveObject {
   String id;
 
   @HiveField(1)
-  int providerRaw;
+  late int providerRaw;
 
   ExchangeProviderDescription get provider =>
       ExchangeProviderDescription.deserialize(raw: providerRaw);
 
   @HiveField(2)
-  int fromRaw;
+  late int fromRaw;
 
   CryptoCurrency get from => CryptoCurrency.deserialize(raw: fromRaw);
 
   @HiveField(3)
-  int toRaw;
+  late int toRaw;
 
   CryptoCurrency get to => CryptoCurrency.deserialize(raw: toRaw);
 
   @HiveField(4)
-  String stateRaw;
+  late String stateRaw;
 
   TradeState get state => TradeState.deserialize(raw: stateRaw);
 
   @HiveField(5)
-  DateTime createdAt;
+  DateTime? createdAt;
 
   @HiveField(6)
-  DateTime expiredAt;
+  DateTime? expiredAt;
 
   @HiveField(7)
   String amount;
 
   @HiveField(8)
-  String inputAddress;
+  String? inputAddress;
 
   @HiveField(9)
-  String extraId;
+  String? extraId;
 
   @HiveField(10)
-  String outputTransaction;
+  String? outputTransaction;
 
   @HiveField(11)
-  String refundAddress;
+  String? refundAddress;
 
   @HiveField(12)
-  String walletId;
+  String? walletId;
 
-  static Trade fromMap(Map map) {
+  static Trade fromMap(Map<String, Object?> map) {
     return Trade(
         id: map['id'] as String,
         provider: ExchangeProviderDescription.deserialize(
@@ -99,7 +108,7 @@ class Trade extends HiveObject {
       'provider': provider.serialize(),
       'input': from.serialize(),
       'output': to.serialize(),
-      'date': createdAt != null ? createdAt.millisecondsSinceEpoch : null,
+      'date': createdAt != null ? createdAt!.millisecondsSinceEpoch : null,
       'amount': amount,
       'wallet_id': walletId
     };

lib/exchange/trade_not_found_exeption.dart

@@ -4,14 +4,14 @@ import 'package:cake_wallet/generated/i18n.dart';
 class TradeNotFoundException implements Exception {
   TradeNotFoundException(this.tradeId, {this.provider, this.description = ''});
 
-  String tradeId;
-  ExchangeProviderDescription provider;
+  String? tradeId;
+  ExchangeProviderDescription? provider;
   String description;
 
   @override
   String toString() {
     var text = tradeId != null && provider != null
-        ? S.current.trade_id_not_found(tradeId, provider.title)
+        ? S.current.trade_id_not_found(tradeId!, provider!.title)
         : S.current.trade_not_found;
     text += ' $description';
 

lib/exchange/trade_state.dart

@@ -2,7 +2,7 @@ import 'package:flutter/foundation.dart';
 import 'package:cw_core/enumerable_item.dart';
 
 class TradeState extends EnumerableItem<String> with Serializable<String> {
-  const TradeState({@required String raw, @required String title})
+  const TradeState({required String raw, required String title})
       : super(raw: raw, title: title);
 
   @override
@@ -35,7 +35,7 @@ class TradeState extends EnumerableItem<String> with Serializable<String> {
   static const completed = TradeState(raw: 'completed', title: 'Completed');
   static const settling = TradeState(raw: 'settling', title: 'Settlement in progress');
   static const settled = TradeState(raw: 'settled', title: 'Settlement completed');
-  static TradeState deserialize({String raw}) {
+  static TradeState deserialize({required String raw}) {
     switch (raw) {
       case 'pending':
         return pending;
@@ -78,7 +78,7 @@ class TradeState extends EnumerableItem<String> with Serializable<String> {
       case 'completed':
         return completed;
       default:
-        return null;
+        throw Exception('Unexpected token: $raw in TradeState deserialize');
     }
   }
 

lib/exchange/xmrto/xmrto_exchange_provider.dart

@@ -34,7 +34,8 @@ class XMRTOExchangeProvider extends ExchangeProvider {
 
   static Future<bool> _checkIsAvailable() async {
     const url = originalApiUri + _orderParameterUriSuffix;
-    final response = await get(url, headers: _headers);
+    final uri = Uri.parse(url);
+    final response = await get(uri, headers: _headers);
     return !(response.statusCode == 403);
   }
 
@@ -61,9 +62,13 @@ class XMRTOExchangeProvider extends ExchangeProvider {
   }
 
   @override
-  Future<Limits> fetchLimits({CryptoCurrency from, CryptoCurrency to, bool isFixedRateMode}) async {
+  Future<Limits> fetchLimits({
+    required CryptoCurrency from,
+    required CryptoCurrency to,
+    required bool isFixedRateMode}) async {
     final url = originalApiUri + _orderParameterUriSuffix;
-    final response = await get(url);
+    final uri = Uri.parse(url);
+    final response = await get(uri);
     final correction = 0.001;
 
     if (response.statusCode != 200) {
@@ -94,16 +99,14 @@ class XMRTOExchangeProvider extends ExchangeProvider {
   }
 
   @override
-  Future<Trade> createTrade({TradeRequest request, bool isFixedRateMode}) async {
+  Future<Trade> createTrade({required TradeRequest request, required bool isFixedRateMode}) async {
     final _request = request as XMRTOTradeRequest;
     final url = originalApiUri + _orderCreateUriSuffix;
     final _amount =
         _request.isBTCRequest ? _request.receiveAmount : _request.amount;
-
     final _amountCurrency = _request.isBTCRequest
         ? _request.to.toString()
         : _request.from.toString();
-
     final pattern = '^([0-9]+([.\,][0-9]{0,8})?|[.\,][0-9]{1,8})\$';
     final isValid = RegExp(pattern).hasMatch(_amount);
 
@@ -115,10 +118,10 @@ class XMRTOExchangeProvider extends ExchangeProvider {
     final body = {
       'amount': _amount,
       'amount_currency': _amountCurrency,
-      'btc_dest_address': _request.address
-    };
+      'btc_dest_address': _request.address};
+    final uri = Uri.parse(url);
     final response =
-        await post(url, headers: _headers, body: json.encode(body));
+        await post(uri, headers: _headers, body: json.encode(body));
 
     if (response.statusCode != 201) {
       if (response.statusCode == 400) {
@@ -145,11 +148,12 @@ class XMRTOExchangeProvider extends ExchangeProvider {
   }
 
   @override
-  Future<Trade> findTradeById({@required String id}) async {
+  Future<Trade> findTradeById({required String id}) async {
     final url = originalApiUri + _orderStatusUriSuffix;
+    final uri = Uri.parse(url);
     final body = {'uuid': id};
     final response =
-        await post(url, headers: _headers, body: json.encode(body));
+        await post(uri, headers: _headers, body: json.encode(body));
 
     if (response.statusCode != 200) {
       if (response.statusCode == 400) {
@@ -188,16 +192,16 @@ class XMRTOExchangeProvider extends ExchangeProvider {
 
   @override
   Future<double> calculateAmount(
-      {CryptoCurrency from,
-      CryptoCurrency to,
-      double amount,
-      bool isFixedRateMode,
-      bool isReceiveAmount}) async {
+      {required CryptoCurrency from,
+      required CryptoCurrency to,
+      required double amount,
+      required bool isFixedRateMode,
+      required bool isReceiveAmount}) async {
     if (from != CryptoCurrency.xmr && to != CryptoCurrency.btc) {
       return 0;
     }
 
-    if (_rate == null || _rate == 0) {
+    if (_rate == 0) {
       _rate = await _fetchRates();
     }
 
@@ -213,7 +217,8 @@ class XMRTOExchangeProvider extends ExchangeProvider {
   Future<double> _fetchRates() async {
     try {
       final url = originalApiUri + _orderParameterUriSuffix;
-      final response = await get(url, headers: _headers);
+      final uri = Uri.parse(url);
+      final response = await get(uri, headers: _headers);
       final responseJSON = json.decode(response.body) as Map<String, dynamic>;
       final price = double.parse(responseJSON['price'] as String);
 

lib/exchange/xmrto/xmrto_trade_request.dart

@@ -4,13 +4,13 @@ import 'package:cake_wallet/exchange/trade_request.dart';
 
 class XMRTOTradeRequest extends TradeRequest {
   XMRTOTradeRequest(
-      {@required this.from,
-      @required this.to,
-      @required this.amount,
-      @required this.receiveAmount,
-      @required this.address,
-      @required this.refundAddress,
-      @required this.isBTCRequest});
+      {required this.from,
+      required this.to,
+      required this.amount,
+      required this.receiveAmount,
+      required this.address,
+      required this.refundAddress,
+      required this.isBTCRequest});
 
   final CryptoCurrency from;
   final CryptoCurrency to;

lib/haven/cw_haven.dart

@@ -2,7 +2,7 @@ part of 'haven.dart';
 
 class CWHavenAccountList extends HavenAccountList {
 	CWHavenAccountList(this._wallet);
-	Object _wallet;
+	final Object _wallet;
 
 	@override
 	@computed
@@ -37,13 +37,13 @@ class CWHavenAccountList extends HavenAccountList {
   }
 
   @override
-  Future<void> addAccount(Object wallet, {String label}) async {
+  Future<void> addAccount(Object wallet, {required String label}) async {
   	final havenWallet = wallet as HavenWallet;
   	await havenWallet.walletAddresses.accountList.addAccount(label: label);
   }
 
   @override
-  Future<void> setLabelAccount(Object wallet, {int accountIndex, String label}) async {
+  Future<void> setLabelAccount(Object wallet, {required int accountIndex, required String label}) async {
   	final havenWallet = wallet as HavenWallet;
   	await havenWallet.walletAddresses.accountList
   		.setLabelAccount(
@@ -54,7 +54,7 @@ class CWHavenAccountList extends HavenAccountList {
 
 class CWHavenSubaddressList extends MoneroSubaddressList {
 	CWHavenSubaddressList(this._wallet);
-	Object _wallet;
+	final Object _wallet;
 
 	@override
 	@computed
@@ -71,13 +71,13 @@ class CWHavenSubaddressList extends MoneroSubaddressList {
   }
 
   @override
-  void update(Object wallet, {int accountIndex}) {
+  void update(Object wallet, {required int accountIndex}) {
   	final havenWallet = wallet as HavenWallet;
   	havenWallet.walletAddresses.subaddressList.update(accountIndex: accountIndex);
   }
 
   @override
-  void refresh(Object wallet, {int accountIndex}) {
+  void refresh(Object wallet, {required int accountIndex}) {
   	final havenWallet = wallet as HavenWallet;
   	havenWallet.walletAddresses.subaddressList.refresh(accountIndex: accountIndex);
   }
@@ -93,7 +93,7 @@ class CWHavenSubaddressList extends MoneroSubaddressList {
   }
 
   @override
-  Future<void> addSubaddress(Object wallet, {int accountIndex, String label}) async {
+  Future<void> addSubaddress(Object wallet, {required int accountIndex, required String label}) async {
   	final havenWallet = wallet as HavenWallet;
   	await havenWallet.walletAddresses.subaddressList
   		.addSubaddress(
@@ -103,7 +103,7 @@ class CWHavenSubaddressList extends MoneroSubaddressList {
 
   @override
   Future<void> setLabelSubaddress(Object wallet,
-      {int accountIndex, int addressIndex, String label}) async {
+      {required int accountIndex, required int addressIndex, required String label}) async {
   	final havenWallet = wallet as HavenWallet;
   	await havenWallet.walletAddresses.subaddressList
   		.setLabelSubaddress(
@@ -115,9 +115,10 @@ class CWHavenSubaddressList extends MoneroSubaddressList {
 
 class CWHavenWalletDetails extends HavenWalletDetails {
 	CWHavenWalletDetails(this._wallet);
-	Object _wallet;
+	final Object _wallet;
 
 	@computed
+  @override
   Account get account {
   	final havenWallet = _wallet as HavenWallet;
   	final acc = havenWallet.walletAddresses.account as monero_account.Account;
@@ -125,10 +126,11 @@ class CWHavenWalletDetails extends HavenWalletDetails {
   }
 
   @computed
+  @override
 	HavenBalance get balance {
 		final havenWallet = _wallet as HavenWallet;
   	final balance = havenWallet.balance;
-  	return null;
+  	throw Exception('Unimplemented');
   	//return HavenBalance(
   	//	fullBalance: balance.fullBalance,
   	//	unlockedBalance: balance.unlockedBalance);
@@ -136,39 +138,48 @@ class CWHavenWalletDetails extends HavenWalletDetails {
 }
 
 class CWHaven extends Haven {
-	HavenAccountList getAccountList(Object wallet) {
+  @override
+  HavenAccountList getAccountList(Object wallet) {
 		return CWHavenAccountList(wallet);
 	}
-	
+
+	@override
 	MoneroSubaddressList getSubaddressList(Object wallet) {
 		return CWHavenSubaddressList(wallet);
 	}
 
+  @override
 	TransactionHistoryBase getTransactionHistory(Object wallet) {
 		final havenWallet = wallet as HavenWallet;
 		return havenWallet.transactionHistory;
 	}
 
+  @override
 	HavenWalletDetails getMoneroWalletDetails(Object wallet) {
 		return CWHavenWalletDetails(wallet);
 	}
 
-	int getHeigthByDate({DateTime date}) {
+  @override
+	int getHeigthByDate({required DateTime date}) {
 		return getMoneroHeigthByDate(date: date);
 	}
 	
+  @override
 	TransactionPriority getDefaultTransactionPriority() {
 		return MoneroTransactionPriority.slow;
 	}
 
-	TransactionPriority deserializeMoneroTransactionPriority({int raw}) {
+  @override
+	TransactionPriority deserializeMoneroTransactionPriority({required int raw}) {
 		return MoneroTransactionPriority.deserialize(raw: raw);
 	}
 
+  @override
 	List<TransactionPriority> getTransactionPriorities() {
 		return MoneroTransactionPriority.all;
 	}
 
+  @override
 	List<String> getMoneroWordList(String language) {
 		switch (language.toLowerCase()) {
 		  case 'english':
@@ -196,14 +207,15 @@ class CWHaven extends Haven {
 		}
 	}
 
+  @override
 	WalletCredentials createHavenRestoreWalletFromKeysCredentials({
-			String name,
-          	String spendKey,
-          	String viewKey,
-          	String address,
-          	String password,
-          	String language,
-          	int height}) {
+			required String name,
+      required String spendKey,
+      required String viewKey,
+      required String address,
+      required String password,
+      required String language,
+      required int height}) {
 		return HavenRestoreWalletFromKeysCredentials(
 			name: name,
 			spendKey: spendKey,
@@ -213,8 +225,13 @@ class CWHaven extends Haven {
 			language: language,
 			height: height);
 	}
-	
-	WalletCredentials createHavenRestoreWalletFromSeedCredentials({String name, String password, int height, String mnemonic}) {
+  
+  @override
+	WalletCredentials createHavenRestoreWalletFromSeedCredentials({
+    required String name,
+    required String password,
+    required int height,
+    required String mnemonic}) {
 		return HavenRestoreWalletFromSeedCredentials(
 			name: name,
 			password: password,
@@ -222,13 +239,18 @@ class CWHaven extends Haven {
 			mnemonic: mnemonic);
 	}
 
-	WalletCredentials createHavenNewWalletCredentials({String name, String password, String language}) {
+  @override
+	WalletCredentials createHavenNewWalletCredentials({
+    required String name,
+    required String language,
+    String? password}) {
 		return HavenNewWalletCredentials(
 			name: name,
 			password: password,
 			language: language);
 	}
 
+  @override
 	Map<String, String> getKeys(Object wallet) {
 		final havenWallet = wallet as HavenWallet;
 		final keys = havenWallet.keys;
@@ -239,7 +261,11 @@ class CWHaven extends Haven {
       'publicViewKey': keys.publicViewKey};
 	}
 
-	Object createHavenTransactionCreationCredentials({List<Output> outputs, TransactionPriority priority, String assetType}) {
+  @override
+	Object createHavenTransactionCreationCredentials({
+    required List<Output> outputs,
+    required TransactionPriority priority,
+    required String assetType}) {
 		return HavenTransactionCreationCredentials(
 			outputs: outputs.map((out) => OutputInfo(
 					fiatAmount: out.fiatAmount,
@@ -255,53 +281,64 @@ class CWHaven extends Haven {
 			assetType: assetType);
 	}
 
-	String formatterMoneroAmountToString({int amount}) {
+  @override
+	String formatterMoneroAmountToString({required int amount}) {
 		return moneroAmountToString(amount: amount);
 	}
-
-	double formatterMoneroAmountToDouble({int amount}) {
+  
+  @override
+	double formatterMoneroAmountToDouble({required int amount}) {
 		return moneroAmountToDouble(amount: amount);
 	}
 
-	int formatterMoneroParseAmount({String amount}) {
+  @override
+	int formatterMoneroParseAmount({required String amount}) {
 		return moneroParseAmount(amount: amount);
 	}
 
+  @override
 	Account getCurrentAccount(Object wallet) {
 		final havenWallet = wallet as HavenWallet;
 		final acc = havenWallet.walletAddresses.account as monero_account.Account;
 		return Account(id: acc.id, label: acc.label);
 	}
 
+  @override
 	void setCurrentAccount(Object wallet, int id, String label) {
 		final havenWallet = wallet as HavenWallet;
 		havenWallet.walletAddresses.account = monero_account.Account(id: id, label: label);
 	}
 
+  @override
 	void onStartup() {
 		monero_wallet_api.onStartup();
 	}
 
+  @override
 	int getTransactionInfoAccountId(TransactionInfo tx) {
 		final havenTransactionInfo = tx as HavenTransactionInfo;
 		return havenTransactionInfo.accountIndex;
 	}
 
+  @override
 	WalletService createHavenWalletService(Box<WalletInfo> walletInfoSource) {
 		return HavenWalletService(walletInfoSource);
 	}
 
+  @override
 	String getTransactionAddress(Object wallet, int accountIndex, int addressIndex) {
 		final havenWallet = wallet as HavenWallet;
 		return havenWallet.getTransactionAddress(accountIndex, addressIndex);
 	}
 
+  @override
 	CryptoCurrency assetOfTransaction(TransactionInfo tx) {
 		final transaction = tx as HavenTransactionInfo;
 		final asset = CryptoCurrency.fromString(transaction.assetType);
 		return asset;
 	}
 
+  @override
 	List<AssetRate> getAssetRate() 
 		=> getRate()
 				.map((rate) => AssetRate(rate.getAssetType(), rate.getRate()))

lib/ionia/ionia_anypay.dart

@@ -1,4 +1,3 @@
-import 'package:flutter/foundation.dart';
 import 'package:cw_core/monero_amount_format.dart';
 import 'package:cw_core/monero_transaction_priority.dart';
 import 'package:cw_core/output_info.dart';
@@ -14,7 +13,6 @@ import 'package:cake_wallet/bitcoin/bitcoin.dart';
 import 'package:cake_wallet/monero/monero.dart';
 import 'package:cake_wallet/anypay/any_pay_payment_committed_info.dart';
 import 'package:cake_wallet/ionia/ionia_any_pay_payment_info.dart';
-import 'package:cake_wallet/ionia/ionia_order.dart';
 
 class IoniaAnyPay {
 	IoniaAnyPay(this.ioniaService, this.anyPayApi, this.wallet);
@@ -24,8 +22,8 @@ class IoniaAnyPay {
 	final WalletBase wallet;
 
 	Future<IoniaAnyPayPaymentInfo> purchase({
-		@required String merchId,
-		@required double amount}) async {
+		required String merchId,
+		required double amount}) async {
 		final invoice = await ioniaService.purchaseGiftCard(
 			merchId: merchId,
 			amount: amount,
@@ -40,7 +38,7 @@ class IoniaAnyPay {
 			.map((AnyPayPaymentInstruction instruction) {
 				switch(payment.chain.toUpperCase()) {
 					case AnyPayChain.xmr:
-						return monero.createMoneroTransactionCreationCredentialsRaw(
+						return monero!.createMoneroTransactionCreationCredentialsRaw(
 							outputs: instruction.outputs.map((out) =>
 							  OutputInfo(
 								isParsedAddress: false,
@@ -50,7 +48,7 @@ class IoniaAnyPay {
 								sendAll: false)).toList(),
 							priority: MoneroTransactionPriority.medium); // FIXME: HARDCODED PRIORITY
 					case AnyPayChain.btc:
-						return bitcoin.createBitcoinTransactionCredentialsRaw(
+						return bitcoin!.createBitcoinTransactionCredentialsRaw(
 							instruction.outputs.map((out) =>
 							  OutputInfo(
 								isParsedAddress: false,
@@ -59,7 +57,7 @@ class IoniaAnyPay {
 								sendAll: false)).toList(),
 							feeRate: instruction.requiredFeeRate);
 					case AnyPayChain.ltc:
-						return bitcoin.createBitcoinTransactionCredentialsRaw(
+						return bitcoin!.createBitcoinTransactionCredentialsRaw(
 							instruction.outputs.map((out) =>
 							  OutputInfo(
 								isParsedAddress: false,
@@ -76,8 +74,8 @@ class IoniaAnyPay {
 			.map((PendingTransaction pendingTransaction) {
 				switch (payment.chain.toUpperCase()){
 				case AnyPayChain.xmr:
-					final ptx = monero.pendingTransactionInfo(pendingTransaction);
-					return AnyPayTransaction(ptx['hex'], id: ptx['id'], key: ptx['key']);
+					final ptx = monero!.pendingTransactionInfo(pendingTransaction);
+					return AnyPayTransaction(ptx['hex'] ?? '', id: ptx['id'] ?? '', key: ptx['key']);
 				default:
 					return AnyPayTransaction(pendingTransaction.hex, id: pendingTransaction.id, key: null);
 				} 

lib/ionia/ionia_api.dart

@@ -1,7 +1,6 @@
 import 'dart:convert';
 import 'package:cake_wallet/ionia/ionia_merchant.dart';
 import 'package:cake_wallet/ionia/ionia_order.dart';
-import 'package:flutter/foundation.dart';
 import 'package:http/http.dart';
 import 'package:cake_wallet/ionia/ionia_user_credentials.dart';
 import 'package:cake_wallet/ionia/ionia_virtual_card.dart';
@@ -27,15 +26,14 @@ class IoniaApi {
 
 	// Create user
 
-	Future<String> createUser(String email, {@required String clientId}) async {
+	Future<String> createUser(String email, {required String clientId}) async {
 		final headers = <String, String>{'clientId': clientId};
 		final query = <String, String>{'emailAddress': email};
 		final uri = createUserUri.replace(queryParameters: query);
 		final response = await put(uri, headers: headers);
 		
 		if (response.statusCode != 200) {
-			// throw exception
-			return null;
+			throw Exception('Unexpected http status: ${response.statusCode}');
 		}
 
 		final bodyJson = json.decode(response.body) as Map<String, Object>;
@@ -52,10 +50,10 @@ class IoniaApi {
 	// Verify email
 
 	Future<IoniaUserCredentials> verifyEmail({
-		@required String username,
-		@required String email,
-		@required String code,
-		@required String clientId}) async {
+		required String username,
+		required String email,
+		required String code,
+		required String clientId}) async {
 		final headers = <String, String>{
 			'clientId': clientId,
 			'username': username,
@@ -65,8 +63,7 @@ class IoniaApi {
 		final response = await put(uri, headers: headers);
 
 		if (response.statusCode != 200) {
-			// throw exception
-			return null;
+			throw Exception('Unexpected http status: ${response.statusCode}');
 		}
 
 		final bodyJson = json.decode(response.body) as Map<String, Object>;
@@ -84,15 +81,14 @@ class IoniaApi {
 
 	// Sign In
 
-	Future<String> signIn(String email, {@required String clientId}) async {
+	Future<String> signIn(String email, {required String clientId}) async {
 		final headers = <String, String>{'clientId': clientId};
 		final query = <String, String>{'emailAddress': email};
 		final uri = signInUri.replace(queryParameters: query);
 		final response = await put(uri, headers: headers);
 		
 		if (response.statusCode != 200) {
-			// throw exception
-			return null;
+		  throw Exception('Unexpected http status: ${response.statusCode}');
 		}
 
 		final bodyJson = json.decode(response.body) as Map<String, Object>;
@@ -109,9 +105,9 @@ class IoniaApi {
 	// Get virtual card
 
 	Future<IoniaVirtualCard> getCards({
-		@required String username,
-		@required String password,
-		@required String clientId}) async {
+		required String username,
+		required String password,
+		required String clientId}) async {
 		final headers = <String, String>{
 			'clientId': clientId,
 			'username': username,
@@ -119,8 +115,7 @@ class IoniaApi {
 		final response = await post(getCardsUri, headers: headers);
 
 		if (response.statusCode != 200) {
-			// throw exception
-			return null;
+		  throw Exception('Unexpected http status: ${response.statusCode}');
 		}
 
 		final bodyJson = json.decode(response.body) as Map<String, Object>;
@@ -138,9 +133,9 @@ class IoniaApi {
 	// Create virtual card
 
 	Future<IoniaVirtualCard> createCard({
-		@required String username,
-		@required String password,
-		@required String clientId}) async {
+		required String username,
+		required String password,
+		required String clientId}) async {
 		final headers = <String, String>{
 			'clientId': clientId,
 			'username': username,
@@ -148,13 +143,12 @@ class IoniaApi {
 		final response = await post(createCardUri, headers: headers);
 
 		if (response.statusCode != 200) {
-			// throw exception
-			return null;
+		  throw Exception('Unexpected http status: ${response.statusCode}');
 		}
 
 		final bodyJson = json.decode(response.body) as Map<String, Object>;
 		final data = bodyJson['Data'] as Map<String, Object>;
-		final isSuccessful = bodyJson['Successful'] as bool;
+		final isSuccessful = bodyJson['Successful'] as bool? ?? false;
 
 		if (!isSuccessful) {
 			throw Exception(data['message'] as String);
@@ -166,9 +160,9 @@ class IoniaApi {
 	// Get Merchants
 
 	Future<List<IoniaMerchant>> getMerchants({
-		@required String username,
-		@required String password,
-		@required String clientId}) async {
+		required String username,
+		required String password,
+		required String clientId}) async {
 	    final headers = <String, String>{
 			'clientId': clientId,
 			'username': username,
@@ -180,32 +174,33 @@ class IoniaApi {
 		}
 
 		final decodedBody = json.decode(response.body) as Map<String, dynamic>;
-		final isSuccessful = decodedBody['Successful'] as bool ?? false;
+		final isSuccessful = decodedBody['Successful'] as bool? ?? false;
     
 		if (!isSuccessful) {
 			return [];
 		}
 
 		final data = decodedBody['Data'] as List<dynamic>;
-		return data.map((dynamic e) {
-			try {
-				final element = e as Map<String, dynamic>;
-				return IoniaMerchant.fromJsonMap(element);
-			} catch(_) {
-				return null;
-			} 
-		}).where((e) => e != null)
-		.toList();
+    final merch = <IoniaMerchant>[];
+
+    for (final item in data) {
+      try {
+				final element = item as Map<String, dynamic>;
+				merch.add(IoniaMerchant.fromJsonMap(element));
+			} catch(_) {} 
+    }
+
+    return merch;
 	}
 
 	// Get Merchants By Filter
 
 	Future<List<IoniaMerchant>> getMerchantsByFilter({
-		@required String username,
-		@required String password,
-		@required String clientId,
-		String search,
-		List<IoniaCategory> categories,
+		required String username,
+		required String password,
+		required String clientId,
+		String? search,
+		List<IoniaCategory>? categories,
 		int merchantFilterType = 0}) async {
 		// MerchantFilterType: {All = 0, Nearby = 1, Popular = 2, Online = 3, MyFaves = 4, Search = 5}
 	    
@@ -234,34 +229,35 @@ class IoniaApi {
 		}
 
 		final decodedBody = json.decode(response.body) as Map<String, dynamic>;
-		final isSuccessful = decodedBody['Successful'] as bool ?? false;
+		final isSuccessful = decodedBody['Successful'] as bool? ?? false;
 
 		if (!isSuccessful) {
 			return [];
 		}
 
 		final data = decodedBody['Data'] as List<dynamic>;
-		return data.map((dynamic e) {
-			try {
-				final element = e['Merchant'] as Map<String, dynamic>;
-				return IoniaMerchant.fromJsonMap(element);
-			} catch(_) {
-				return null;
-			}
-		}).where((e) => e != null)
-		.toList();
+    final merch = <IoniaMerchant>[];
+
+    for (final item in data) {
+      try {
+				final element = item['Merchant'] as Map<String, dynamic>;
+				merch.add(IoniaMerchant.fromJsonMap(element));
+			} catch(_) {}
+    }
+		
+    return merch;
 	}
 
 	// Purchase Gift Card
 
 	Future<IoniaOrder> purchaseGiftCard({
-		@required String requestedUUID,
-		@required String merchId,
-		@required double amount,
-		@required String currency,
-		@required String username,
-		@required String password,
-		@required String clientId}) async {
+		required String requestedUUID,
+		required String merchId,
+		required double amount,
+		required String currency,
+		required String username,
+		required String password,
+		required String clientId}) async {
 		final headers = <String, String>{
 			'clientId': clientId,
 			'username': username,
@@ -279,7 +275,7 @@ class IoniaApi {
 		}
 
     	final decodedBody = json.decode(response.body) as Map<String, dynamic>;
-		final isSuccessful = decodedBody['Successful'] as bool ?? false;
+		final isSuccessful = decodedBody['Successful'] as bool? ?? false;
 
 		if (!isSuccessful) {
 			throw Exception(decodedBody['ErrorMessage'] as String);
@@ -292,9 +288,9 @@ class IoniaApi {
 	// Get Current User Gift Card Summaries
 
 	Future<List<IoniaGiftCard>> getCurrentUserGiftCardSummaries({
-		@required String username,
-		@required String password,
-		@required String clientId}) async {
+		required String username,
+		required String password,
+		required String clientId}) async {
 	    final headers = <String, String>{
 			'clientId': clientId,
 			'username': username,
@@ -306,32 +302,33 @@ class IoniaApi {
 		}
 
 		final decodedBody = json.decode(response.body) as Map<String, dynamic>;
-		final isSuccessful = decodedBody['Successful'] as bool ?? false;
+		final isSuccessful = decodedBody['Successful'] as bool? ?? false;
     
 		if (!isSuccessful) {
 			return [];
 		}
 
 		final data = decodedBody['Data'] as List<dynamic>;
-		return data.map((dynamic e) {
-			try {
-				final element = e as Map<String, dynamic>;
-				return IoniaGiftCard.fromJsonMap(element);
-			} catch(e) {
-				return null;
-			}
-		}).where((e) => e != null)
-		.toList();
+    final cards = <IoniaGiftCard>[];
+
+    for (final item in data) {
+      try {
+				final element = item as Map<String, dynamic>;
+				cards.add(IoniaGiftCard.fromJsonMap(element));
+			} catch(_) {}
+    }
+
+    return cards;
 	}
 
 	// Charge Gift Card
 
 	Future<void> chargeGiftCard({
-		@required String username,
-		@required String password,
-		@required String clientId,
-		@required int giftCardId,
-		@required double amount}) async {
+		required String username,
+		required String password,
+		required String clientId,
+		required int giftCardId,
+		required double amount}) async {
 		final headers = <String, String>{
 			'clientId': clientId,
 			'username': username,
@@ -350,11 +347,11 @@ class IoniaApi {
 		}
 
 		final decodedBody = json.decode(response.body) as Map<String, dynamic>;
-		final isSuccessful = decodedBody['Successful'] as bool ?? false;
+		final isSuccessful = decodedBody['Successful'] as bool? ?? false;
 
 		if (!isSuccessful) {
 			final data = decodedBody['Data'] as Map<String, dynamic>;
-			final msg = data['Message'] as String ?? '';
+			final msg = data['Message'] as String? ?? '';
 
 			if (msg.isNotEmpty) {
 				throw Exception(msg);
@@ -367,10 +364,10 @@ class IoniaApi {
 	// Get Gift Card
 
 	Future<IoniaGiftCard> getGiftCard({
-		@required String username,
-		@required String password,
-		@required String clientId,
-		@required int id}) async {
+		required String username,
+		required String password,
+		required String clientId,
+		required int id}) async {
 		final headers = <String, String>{
 			'clientId': clientId,
 			'username': username,
@@ -387,7 +384,7 @@ class IoniaApi {
 		}
 
 		final decodedBody = json.decode(response.body) as Map<String, dynamic>;
-		final isSuccessful = decodedBody['Successful'] as bool ?? false;
+		final isSuccessful = decodedBody['Successful'] as bool? ?? false;
 
 		if (!isSuccessful) {
 			final msg = decodedBody['ErrorMessage'] as String ?? '';
@@ -406,11 +403,11 @@ class IoniaApi {
 	// Payment Status
 
 	Future<int> getPaymentStatus({
-		@required String username,
-		@required String password,
-		@required String clientId,
-		@required String orderId,
-		@required String paymentId}) async {
+		required String username,
+		required String password,
+		required String clientId,
+		required String orderId,
+		required String paymentId}) async {
 		final headers = <String, String>{
 			'clientId': clientId,
 			'username': username,
@@ -429,7 +426,7 @@ class IoniaApi {
 		}
 
 		final decodedBody = json.decode(response.body) as Map<String, dynamic>;
-		final isSuccessful = decodedBody['Successful'] as bool ?? false;
+		final isSuccessful = decodedBody['Successful'] as bool? ?? false;
 
 		if (!isSuccessful) {
 			final msg = decodedBody['ErrorMessage'] as String ?? '';

lib/ionia/ionia_category.dart

@@ -1,5 +1,9 @@
 class IoniaCategory {
-  const IoniaCategory({this.index, this.title, this.ids, this.iconPath});
+  const IoniaCategory({
+    required this.index,
+    required this.title,
+    required this.ids,
+    required this.iconPath});
 
   static const allCategories = <IoniaCategory>[all, apparel, onlineOnly, food, entertainment, delivery, travel];
   static const all = IoniaCategory(index: 0, title: 'All', ids: [], iconPath: 'assets/images/category.png');

lib/ionia/ionia_create_state.dart

@@ -10,7 +10,7 @@ class IoniaCreateStateSuccess extends IoniaCreateAccountState {}
 class IoniaCreateStateLoading extends IoniaCreateAccountState {}
 
 class IoniaCreateStateFailure extends IoniaCreateAccountState {
-  IoniaCreateStateFailure({@required this.error});
+  IoniaCreateStateFailure({required this.error});
 
   final String error;
 }
@@ -26,7 +26,7 @@ class IoniaOtpSendDisabled extends IoniaOtpState {}
 class IoniaOtpSendEnabled extends IoniaOtpState {}
 
 class IoniaOtpFailure extends IoniaOtpState {
-  IoniaOtpFailure({@required this.error});
+  IoniaOtpFailure({required this.error});
 
   final String error;
 }
@@ -38,7 +38,7 @@ class IoniaCreateCardSuccess extends IoniaCreateCardState {}
 class IoniaCreateCardLoading extends IoniaCreateCardState {}
 
 class IoniaCreateCardFailure extends IoniaCreateCardState {
-  IoniaCreateCardFailure({@required this.error});
+  IoniaCreateCardFailure({required this.error});
 
   final String error;
 }
@@ -52,13 +52,15 @@ class IoniaFetchingCard extends IoniaFetchCardState {}
 class IoniaFetchCardFailure extends IoniaFetchCardState {}
 
 class IoniaCardSuccess extends IoniaFetchCardState {
-  IoniaCardSuccess({@required this.card});
+  IoniaCardSuccess({required this.card});
 
   final IoniaVirtualCard card;
 }
 
 abstract class IoniaMerchantState {}
 
+class InitialIoniaMerchantLoadingState extends IoniaMerchantState {}
+
 class IoniaLoadingMerchantState extends IoniaMerchantState {}
 
 class IoniaLoadedMerchantState extends IoniaMerchantState {}

lib/ionia/ionia_gift_card.dart

@@ -4,25 +4,25 @@ import 'package:flutter/foundation.dart';
 
 class IoniaGiftCard {
     IoniaGiftCard({
-        @required this.id,
-        @required this.merchantId,
-        @required this.legalName,
-        @required this.systemName,
-        @required this.barcodeUrl,
-        @required this.cardNumber,
-        @required this.cardPin,
-        @required this.instructions,
-        @required this.tip,
-        @required this.purchaseAmount,
-        @required this.actualAmount,
-        @required this.totalTransactionAmount,
-        @required this.totalDashTransactionAmount,
-        @required this.remainingAmount,
-        @required this.createdDateFormatted,
-        @required this.lastTransactionDateFormatted,
-        @required this.isActive,
-        @required this.isEmpty,
-        @required this.logoUrl});
+        required this.id,
+        required this.merchantId,
+        required this.legalName,
+        required this.systemName,
+        required this.barcodeUrl,
+        required this.cardNumber,
+        required this.cardPin,
+        required this.instructions,
+        required this.tip,
+        required this.purchaseAmount,
+        required this.actualAmount,
+        required this.totalTransactionAmount,
+        required this.totalDashTransactionAmount,
+        required this.remainingAmount,
+        required this.createdDateFormatted,
+        required this.lastTransactionDateFormatted,
+        required this.isActive,
+        required this.isEmpty,
+        required this.logoUrl});
 
     factory IoniaGiftCard.fromJsonMap(Map<String, dynamic> element) {
         return IoniaGiftCard(

lib/ionia/ionia_gift_card_instruction.dart

@@ -6,7 +6,7 @@ class IoniaGiftCardInstruction {
 
     factory IoniaGiftCardInstruction.fromJsonMap(Map<String, dynamic> element) {
         return IoniaGiftCardInstruction(
-            toBeginningOfSentenceCase(element['title'] as String ?? ''),
+            toBeginningOfSentenceCase(element['title'] as String? ?? '') ?? '',
             element['description'] as String);
     }
 

lib/ionia/ionia_merchant.dart

@@ -1,63 +1,31 @@
-import 'package:flutter/foundation.dart';
 import 'package:cake_wallet/ionia/ionia_gift_card_instruction.dart';
 import 'package:cake_wallet/generated/i18n.dart';
 
 class IoniaMerchant  {
 	IoniaMerchant({
-		@required this.id,
-		@required this.legalName,
-		@required this.systemName,
-		@required this.description,
-		@required this.website,
-		@required this.termsAndConditions,
-		@required this.logoUrl,
-		@required this.cardImageUrl,
-		@required this.cardholderAgreement,
-		@required this.purchaseFee,
-		@required this.revenueShare,
-		@required this.marketingFee,
-		@required this.minimumDiscount,
-		@required this.level1,
-		@required this.level2, 
-		@required this.level3,
-		@required this.level4,
-		@required this.level5,
-		@required this.level6,
-		@required this.level7,
-		@required this.isActive,
-		@required this.isDeleted,
-		@required this.isOnline,
-		@required this.isPhysical,
-		@required this.isVariablePurchase,
-		@required this.minimumCardPurchase,
-		@required this.maximumCardPurchase,
-		@required this.acceptsTips,
-		@required this.createdDateFormatted,
-		@required this.createdBy,
-		@required this.isRegional,
-		@required this.modifiedDateFormatted,
-		@required this.modifiedBy,
-		@required this.usageInstructions,
-		@required this.usageInstructionsBak,
-		@required this.paymentGatewayId,
-		@required this.giftCardGatewayId,
-		@required this.isHtmlDescription,
-		@required this.purchaseInstructions,
-		@required this.balanceInstructions,
-		@required this.amountPerCard,
-		@required this.processingMessage,
-		@required this.hasBarcode,
-		@required this.hasInventory,
-		@required this.isVoidable,
-		@required this.receiptMessage,
-		@required this.cssBorderCode,
-		@required this.instructions,
-		@required this.alderSku,
-		@required this.ngcSku,
-		@required this.acceptedCurrency,
-		@required this.deepLink,
-		@required this.isPayLater,
-        @required this.savingsPercentage});
+		required this.id,
+		required this.legalName,
+		required this.systemName,
+		required this.description,
+		required this.website,
+		required this.termsAndConditions,
+		required this.logoUrl,
+		required this.cardImageUrl,
+		required this.cardholderAgreement,
+		required this.isActive,
+		required this.isOnline,
+		required this.isPhysical,
+		required this.isVariablePurchase,
+		required this.minimumCardPurchase,
+		required this.maximumCardPurchase,
+		required this.acceptsTips,
+		required this.createdDateFormatted,
+		required this.modifiedDateFormatted,
+		required this.usageInstructions,
+		required this.usageInstructionsBak,
+		required this.hasBarcode,
+		required this.instructions,
+        required this.savingsPercentage});
 
 	factory IoniaMerchant.fromJsonMap(Map<String, dynamic> element) {
 		return IoniaMerchant(
@@ -70,50 +38,19 @@ class IoniaMerchant  {
             logoUrl: element["LogoUrl"] as String,
             cardImageUrl: element["CardImageUrl"] as String,
             cardholderAgreement: element["CardholderAgreement"] as String,
-            purchaseFee: element["PurchaseFee"] as double,
-            revenueShare: element["RevenueShare"] as double,
-            marketingFee: element["MarketingFee"] as double,
-            minimumDiscount: element["MinimumDiscount"] as double,
-            level1: element["Level1"] as double,
-            level2: element["Level2"] as double,
-            level3: element["Level3"] as double,
-            level4: element["Level4"] as double,
-            level5: element["Level5"] as double,
-            level6: element["Level6"] as double,
-            level7: element["Level7"] as double,
-            isActive: element["IsActive"] as bool,
-            isDeleted: element["IsDeleted"] as bool,
+            isActive: element["IsActive"] as bool?,
             isOnline: element["IsOnline"] as bool,
             isPhysical: element["IsPhysical"] as bool,
             isVariablePurchase: element["IsVariablePurchase"] as bool,
             minimumCardPurchase: element["MinimumCardPurchase"] as double,
             maximumCardPurchase: element["MaximumCardPurchase"] as double,
             acceptsTips: element["AcceptsTips"] as bool,
-            createdDateFormatted: element["CreatedDate"] as String,
-            createdBy: element["CreatedBy"] as int,
-            isRegional: element["IsRegional"] as bool,
-            modifiedDateFormatted: element["ModifiedDate"] as String,
-            modifiedBy: element["ModifiedBy"] as int,
-            usageInstructions: element["UsageInstructions"] as String,
-            usageInstructionsBak: element["UsageInstructionsBak"] as String,
-            paymentGatewayId: element["PaymentGatewayId"] as int,
-            giftCardGatewayId: element["GiftCardGatewayId"] as int ,
-            isHtmlDescription: element["IsHtmlDescription"] as bool,
-            purchaseInstructions: element["PurchaseInstructions"] as String,
-            balanceInstructions: element["BalanceInstructions"] as String,
-            amountPerCard: element["AmountPerCard"] as double,
-            processingMessage: element["ProcessingMessage"] as String,
+            createdDateFormatted: element["CreatedDate"] as String?,
+            modifiedDateFormatted: element["ModifiedDate"] as String?,
+            usageInstructions: element["UsageInstructions"] as String?,
+            usageInstructionsBak: element["UsageInstructionsBak"] as String?,
             hasBarcode: element["HasBarcode"] as bool,
-            hasInventory: element["HasInventory"] as bool,
-            isVoidable: element["IsVoidable"] as bool,
-            receiptMessage: element["ReceiptMessage"] as String,
-            cssBorderCode: element["CssBorderCode"] as String,
             instructions: IoniaGiftCardInstruction.parseListOfInstructions(element['PaymentInstructions'] as String),
-            alderSku: element["AlderSku"] as String,
-            ngcSku: element["NgcSku"] as String,
-            acceptedCurrency: element["AcceptedCurrency"] as String,
-            deepLink: element["DeepLink"] as String,
-            isPayLater: element["IsPayLater"] as bool,
             savingsPercentage: element["SavingsPercentage"] as double);
 	}
 
@@ -126,50 +63,19 @@ class IoniaMerchant  {
     final String logoUrl;
     final String cardImageUrl;
     final String cardholderAgreement;
-    final double purchaseFee;
-    final double revenueShare;
-    final double marketingFee;
-    final double minimumDiscount;
-    final double level1;
-    final double level2;
-    final double level3;
-    final double level4;
-    final double level5;
-    final double level6;
-    final double level7;
-    final bool isActive;
-    final bool isDeleted;
+    final bool? isActive;
     final bool isOnline;
-    final bool isPhysical;
+    final bool? isPhysical;
     final bool isVariablePurchase;
     final double minimumCardPurchase;
     final double maximumCardPurchase;
     final bool acceptsTips;
-    final String createdDateFormatted;
-    final int createdBy;
-    final bool isRegional;
-    final String modifiedDateFormatted;
-    final int modifiedBy;
-    final String usageInstructions;
-    final String usageInstructionsBak;
-    final int paymentGatewayId;
-    final int giftCardGatewayId;
-    final bool isHtmlDescription;
-    final String purchaseInstructions;
-    final String balanceInstructions;
-    final double amountPerCard;
-    final String processingMessage;
+    final String? createdDateFormatted;
+    final String? modifiedDateFormatted;
+    final String? usageInstructions;
+    final String? usageInstructionsBak;
     final bool hasBarcode;
-    final bool hasInventory;
-    final bool isVoidable;
-    final String receiptMessage;
-    final String cssBorderCode;
     final List<IoniaGiftCardInstruction> instructions;
-    final String alderSku;
-    final String ngcSku;
-    final String acceptedCurrency;
-    final String deepLink;
-    final bool isPayLater;
     final double savingsPercentage;
 
     double get discount => savingsPercentage;
@@ -181,7 +87,7 @@ class IoniaMerchant  {
           status += S.current.online;
         }
 
-        if (isPhysical) {
+        if (isPhysical ?? false) {
           if (status.isNotEmpty) {
             status = '$status & ';
           }

lib/ionia/ionia_order.dart

@@ -1,11 +1,11 @@
 import 'package:flutter/foundation.dart';
 
 class IoniaOrder {
-  IoniaOrder({@required this.id,
-    @required this.uri,
-    @required this.currency,
-    @required this.amount,
-    @required this.paymentId});
+  IoniaOrder({required this.id,
+    required this.uri,
+    required this.currency,
+    required this.amount,
+    required this.paymentId});
   factory IoniaOrder.fromMap(Map<String, dynamic> obj) {
     return IoniaOrder(
       id: obj['order_id'] as String,

lib/ionia/ionia_service.dart

@@ -1,7 +1,6 @@
 import 'package:cake_wallet/ionia/ionia_merchant.dart';
 import 'package:cake_wallet/ionia/ionia_order.dart';
 import 'package:cake_wallet/ionia/ionia_virtual_card.dart';
-import 'package:flutter/foundation.dart';
 import 'package:flutter_secure_storage/flutter_secure_storage.dart';
 import 'package:cake_wallet/.secrets.g.dart' as secrets;
 import 'package:cake_wallet/ionia/ionia_api.dart';
@@ -32,8 +31,8 @@ class IoniaService {
 	// Verify email
 
 	Future<void> verifyEmail(String code) async {
-		final username = await secureStorage.read(key: ioniaUsernameStorageKey);
-		final email = await secureStorage.read(key: ioniaEmailStorageKey);
+		final username = (await secureStorage.read(key: ioniaUsernameStorageKey))!;
+		final email = (await secureStorage.read(key: ioniaEmailStorageKey))!;
 		final credentials = await ioniaApi.verifyEmail(email: email, username: username, code: code, clientId: clientId);
 		await secureStorage.write(key: ioniaPasswordStorageKey, value: credentials.password);
 		await secureStorage.write(key: ioniaUsernameStorageKey, value: credentials.username);
@@ -48,7 +47,7 @@ class IoniaService {
 	}
 
 	Future<String> getUserEmail() async {
-		return secureStorage.read(key: ioniaEmailStorageKey);
+		return (await secureStorage.read(key: ioniaEmailStorageKey))!;
 	}
 
 	// Check is user logined
@@ -69,35 +68,35 @@ class IoniaService {
 	// Create virtual card
 
 	Future<IoniaVirtualCard> createCard() async {
-		final username = await secureStorage.read(key: ioniaUsernameStorageKey);
-		final password = await secureStorage.read(key: ioniaPasswordStorageKey);
+		final username = (await secureStorage.read(key: ioniaUsernameStorageKey))!;
+		final password = (await secureStorage.read(key: ioniaPasswordStorageKey))!;
 		return ioniaApi.createCard(username: username, password: password, clientId: clientId);
 	}
 
 	// Get virtual card
 
 	Future<IoniaVirtualCard> getCard() async {
-		final username = await secureStorage.read(key: ioniaUsernameStorageKey);
-		final password = await secureStorage.read(key: ioniaPasswordStorageKey);
+		final username = (await secureStorage.read(key: ioniaUsernameStorageKey))!;
+		final password = (await secureStorage.read(key: ioniaPasswordStorageKey))!;
 		return ioniaApi.getCards(username: username, password: password, clientId: clientId);
 	}
 
 	// Get Merchants
 
 	Future<List<IoniaMerchant>> getMerchants() async {
-		final username = await secureStorage.read(key: ioniaUsernameStorageKey);
-		final password = await secureStorage.read(key: ioniaPasswordStorageKey);
+		final username = (await secureStorage.read(key: ioniaUsernameStorageKey))!;
+		final password = (await secureStorage.read(key: ioniaPasswordStorageKey))!;
 		return ioniaApi.getMerchants(username: username, password: password, clientId: clientId);
 	}
 
 	// Get Merchants By Filter
 
 	Future<List<IoniaMerchant>> getMerchantsByFilter({
-		String search,
-		List<IoniaCategory> categories,
+		String? search,
+		List<IoniaCategory>? categories,
 		int merchantFilterType = 0}) async {
-		final username = await secureStorage.read(key: ioniaUsernameStorageKey);
-		final password = await secureStorage.read(key: ioniaPasswordStorageKey);
+		final username = (await secureStorage.read(key: ioniaUsernameStorageKey))!;
+		final password = (await secureStorage.read(key: ioniaPasswordStorageKey))!;
 		return ioniaApi.getMerchantsByFilter(
 			username: username,
 			password: password,
@@ -110,14 +109,14 @@ class IoniaService {
 	// Purchase Gift Card
 
 	Future<IoniaOrder> purchaseGiftCard({
-		@required String merchId,
-		@required double amount,
-		@required String currency}) async {
-		final username = await secureStorage.read(key: ioniaUsernameStorageKey);
-		final password = await secureStorage.read(key: ioniaPasswordStorageKey);
+		required String merchId,
+		required double amount,
+		required String currency}) async {
+		final username = (await secureStorage.read(key: ioniaUsernameStorageKey))!;
+		final password = (await secureStorage.read(key: ioniaPasswordStorageKey))!;
 		final deviceId = await PlatformDeviceId.getDeviceId;
 		return ioniaApi.purchaseGiftCard(
-			requestedUUID: deviceId,
+			requestedUUID: deviceId!,
 			merchId: merchId,
 			amount: amount,
 			currency: currency,
@@ -129,18 +128,18 @@ class IoniaService {
 	// Get Current User Gift Card Summaries
 
 	Future<List<IoniaGiftCard>> getCurrentUserGiftCardSummaries() async {
-		final username = await secureStorage.read(key: ioniaUsernameStorageKey);
-		final password = await secureStorage.read(key: ioniaPasswordStorageKey);
+		final username = (await secureStorage.read(key: ioniaUsernameStorageKey))!;
+		final password = (await secureStorage.read(key: ioniaPasswordStorageKey))!;
 		return ioniaApi.getCurrentUserGiftCardSummaries(username: username, password: password, clientId: clientId);
 	}
 
 	// Charge Gift Card
 
 	Future<void> chargeGiftCard({
-		@required int giftCardId,
-		@required double amount}) async {
-		final username = await secureStorage.read(key: ioniaUsernameStorageKey);
-		final password = await secureStorage.read(key: ioniaPasswordStorageKey);
+		required int giftCardId,
+		required double amount}) async {
+		final username = (await secureStorage.read(key: ioniaUsernameStorageKey))!;
+		final password = (await secureStorage.read(key: ioniaPasswordStorageKey))!;
 		await ioniaApi.chargeGiftCard(
 			username: username,
 			password: password,
@@ -157,19 +156,19 @@ class IoniaService {
 
 	// Get Gift Card
 
-	Future<IoniaGiftCard> getGiftCard({@required int id}) async {
-		final username = await secureStorage.read(key: ioniaUsernameStorageKey);
-		final password = await secureStorage.read(key: ioniaPasswordStorageKey);
+	Future<IoniaGiftCard> getGiftCard({required int id}) async {
+		final username = (await secureStorage.read(key: ioniaUsernameStorageKey))!;
+		final password = (await secureStorage.read(key: ioniaPasswordStorageKey))!;
 		return ioniaApi.getGiftCard(username: username, password: password, clientId: clientId,id: id);
 	}
 
 	// Payment Status
 
 	Future<int> getPaymentStatus({
-		@required String orderId,
-		@required String paymentId}) async {
-		final username = await secureStorage.read(key: ioniaUsernameStorageKey);
-		final password = await secureStorage.read(key: ioniaPasswordStorageKey);
+		required String orderId,
+		required String paymentId}) async {
+		final username = (await secureStorage.read(key: ioniaUsernameStorageKey))!;
+		final password = (await secureStorage.read(key: ioniaPasswordStorageKey))!;
 		return ioniaApi.getPaymentStatus(username: username, password: password, clientId: clientId, orderId: orderId, paymentId: paymentId);
 	}
 }

lib/ionia/ionia_tip.dart

@@ -1,8 +1,13 @@
 class IoniaTip {
-  const IoniaTip({this.originalAmount, this.percentage, this.isCustom = false});
+  const IoniaTip({
+    required this.originalAmount,
+    required this.percentage,
+    this.isCustom = false});
+
   final double originalAmount;
   final double percentage;
   final bool isCustom;
+  
   double get additionalAmount => double.parse((originalAmount * percentage / 100).toStringAsFixed(2));
 
   static const tipList = [

lib/ionia/ionia_token_data.dart

@@ -2,7 +2,7 @@ import 'package:flutter/foundation.dart';
 import 'dart:convert';
 
 class IoniaTokenData {
-	IoniaTokenData({@required this.accessToken, @required this.tokenType, @required this.expiredAt});
+	IoniaTokenData({required this.accessToken, required this.tokenType, required this.expiredAt});
 
 	factory IoniaTokenData.fromJson(String source) {
 		final decoded = json.decode(source) as Map<String, dynamic>;

lib/ionia/ionia_virtual_card.dart

@@ -1,17 +1,15 @@
-import 'package:flutter/foundation.dart';
-
 class IoniaVirtualCard {
 	IoniaVirtualCard({
-		@required this.token,
-		@required this.createdAt,
-		@required this.lastFour,
-		@required this.state,
-		@required this.pan,
-		@required this.cvv,
-		@required this.expirationMonth,
-		@required this.expirationYear,
-		@required this.fundsLimit,
-		@required this.spendLimit});
+		required this.token,
+		required this.createdAt,
+		required this.lastFour,
+		required this.state,
+		required this.pan,
+		required this.cvv,
+		required this.expirationMonth,
+		required this.expirationYear,
+		required this.fundsLimit,
+		required this.spendLimit});
 	
 	factory IoniaVirtualCard.fromMap(Map<String, Object> source) {
 		final created = source['created'] as String;
@@ -37,7 +35,7 @@ class IoniaVirtualCard {
 	final String cvv;
 	final String expirationMonth;
 	final String expirationYear;
-	final DateTime createdAt;
+	final DateTime? createdAt;
 	final double fundsLimit;
 	final double spendLimit;
 }

lib/main.dart

@@ -109,7 +109,7 @@ Future<void> main() async {
     final templates = await Hive.openBox<Template>(Template.boxName);
     final exchangeTemplates =
         await Hive.openBox<ExchangeTemplate>(ExchangeTemplate.boxName);
-    Box<UnspentCoinsInfo> unspentCoinsInfoSource;
+    Box<UnspentCoinsInfo>? unspentCoinsInfoSource;
     
     if (!isMoneroOnly) {
       unspentCoinsInfoSource = await Hive.openBox<UnspentCoinsInfo>(UnspentCoinsInfo.boxName);
@@ -145,18 +145,18 @@ Future<void> main() async {
 }
 
 Future<void> initialSetup(
-    {@required SharedPreferences sharedPreferences,
-    @required Box<Node> nodes,
-    @required Box<WalletInfo> walletInfoSource,
-    @required Box<Contact> contactSource,
-    @required Box<Trade> tradesSource,
-    @required Box<Order> ordersSource,
-    // @required FiatConvertationService fiatConvertationService,
-    @required Box<Template> templates,
-    @required Box<ExchangeTemplate> exchangeTemplates,
-    @required Box<TransactionDescription> transactionDescriptions,
-    @required Box<UnspentCoinsInfo> unspentCoinsInfoSource,
-    FlutterSecureStorage secureStorage,
+    {required SharedPreferences sharedPreferences,
+    required Box<Node> nodes,
+    required Box<WalletInfo> walletInfoSource,
+    required Box<Contact> contactSource,
+    required Box<Trade> tradesSource,
+    required Box<Order> ordersSource,
+    // required FiatConvertationService fiatConvertationService,
+    required Box<Template> templates,
+    required Box<ExchangeTemplate> exchangeTemplates,
+    required Box<TransactionDescription> transactionDescriptions,
+    required FlutterSecureStorage secureStorage,
+    Box<UnspentCoinsInfo>? unspentCoinsInfoSource,
     int initialMigrationVersion = 15}) async {
   LanguageService.loadLocaleList();
   await defaultSettingsMigration(
@@ -188,14 +188,14 @@ class App extends StatefulWidget {
 }
 
 class AppState extends State<App> with SingleTickerProviderStateMixin {
-  AppState() {
-    yatStore = getIt.get<YatStore>();
+  AppState()
+    : yatStore = getIt.get<YatStore>() {
     SystemChrome.setPreferredOrientations(
         [DeviceOrientation.portraitUp, DeviceOrientation.portraitDown]);
   }
 
   YatStore yatStore;
-  StreamSubscription stream;
+  StreamSubscription? stream;
 
   @override
   void initState() {
@@ -227,7 +227,7 @@ class AppState extends State<App> with SingleTickerProviderStateMixin {
 
   void _handleIncomingLinks() {
     if (!kIsWeb) {
-      stream = getUriLinksStream().listen((Uri uri) {
+      stream = getUriLinksStream().listen((Uri? uri) {
         print('uri: $uri');
         if (!mounted) return;
         //_fetchEmojiFromUri(uri);
@@ -256,7 +256,8 @@ class AppState extends State<App> with SingleTickerProviderStateMixin {
   @override
   Widget build(BuildContext context) {
     return Observer(builder: (BuildContext context) {
-      final settingsStore = getIt.get<AppStore>().settingsStore;
+      final appStore = getIt.get<AppStore>();
+      final settingsStore = appStore.settingsStore;
       final statusBarColor = Colors.transparent;
       final authenticationStore = getIt.get<AuthenticationStore>();
       final initialRoute =
@@ -277,6 +278,7 @@ class AppState extends State<App> with SingleTickerProviderStateMixin {
 
       return Root(
           key: rootKey,
+          appStore: appStore,
           authenticationStore: authenticationStore,
           navigatorKey: navigatorKey,
           child: MaterialApp(

lib/monero/cw_monero.dart

@@ -37,13 +37,13 @@ class CWMoneroAccountList extends MoneroAccountList {
   }
 
   @override
-  Future<void> addAccount(Object wallet, {String label}) async {
+  Future<void> addAccount(Object wallet, {required String label}) async {
   	final moneroWallet = wallet as MoneroWallet;
   	await moneroWallet.walletAddresses.accountList.addAccount(label: label);
   }
 
   @override
-  Future<void> setLabelAccount(Object wallet, {int accountIndex, String label}) async {
+  Future<void> setLabelAccount(Object wallet, {required int accountIndex, required String label}) async {
   	final moneroWallet = wallet as MoneroWallet;
   	await moneroWallet.walletAddresses.accountList
   		.setLabelAccount(
@@ -54,7 +54,7 @@ class CWMoneroAccountList extends MoneroAccountList {
 
 class CWMoneroSubaddressList extends MoneroSubaddressList {
 	CWMoneroSubaddressList(this._wallet);
-	Object _wallet;
+	final Object _wallet;
 
 	@override
 	@computed
@@ -71,13 +71,13 @@ class CWMoneroSubaddressList extends MoneroSubaddressList {
   }
 
   @override
-  void update(Object wallet, {int accountIndex}) {
+  void update(Object wallet, {required int accountIndex}) {
   	final moneroWallet = wallet as MoneroWallet;
   	moneroWallet.walletAddresses.subaddressList.update(accountIndex: accountIndex);
   }
 
   @override
-  void refresh(Object wallet, {int accountIndex}) {
+  void refresh(Object wallet, {required int accountIndex}) {
   	final moneroWallet = wallet as MoneroWallet;
   	moneroWallet.walletAddresses.subaddressList.refresh(accountIndex: accountIndex);
   }
@@ -93,7 +93,7 @@ class CWMoneroSubaddressList extends MoneroSubaddressList {
   }
 
   @override
-  Future<void> addSubaddress(Object wallet, {int accountIndex, String label}) async {
+  Future<void> addSubaddress(Object wallet, {required int accountIndex, required String label}) async {
   	final moneroWallet = wallet as MoneroWallet;
   	await moneroWallet.walletAddresses.subaddressList
   		.addSubaddress(
@@ -103,7 +103,7 @@ class CWMoneroSubaddressList extends MoneroSubaddressList {
 
   @override
   Future<void> setLabelSubaddress(Object wallet,
-      {int accountIndex, int addressIndex, String label}) async {
+      {required int accountIndex, required int addressIndex, required String label}) async {
   	final moneroWallet = wallet as MoneroWallet;
   	await moneroWallet.walletAddresses.subaddressList
   		.setLabelSubaddress(
@@ -115,20 +115,23 @@ class CWMoneroSubaddressList extends MoneroSubaddressList {
 
 class CWMoneroWalletDetails extends MoneroWalletDetails {
 	CWMoneroWalletDetails(this._wallet);
-	Object _wallet;
+	final Object _wallet;
 
 	@computed
+  @override
   Account get account {
   	final moneroWallet = _wallet as MoneroWallet;
   	final acc = moneroWallet.walletAddresses.account;
-  	return Account(id: acc.id, label: acc.label);
+  	return Account(id: acc!.id, label: acc.label);
   }
 
   @computed
+  @override
 	MoneroBalance get balance {
 		final moneroWallet = _wallet as MoneroWallet;
   	final balance = moneroWallet.balance;
-  	return MoneroBalance();
+    throw Exception('Unimplemented');
+  	// return MoneroBalance();
   	//return MoneroBalance(
   	//	fullBalance: balance.fullBalance,
   	//	unlockedBalance: balance.unlockedBalance);
@@ -136,6 +139,7 @@ class CWMoneroWalletDetails extends MoneroWalletDetails {
 }
 
 class CWMonero extends Monero {
+  @override
 	MoneroAccountList getAccountList(Object wallet) {
 		return CWMoneroAccountList(wallet);
 	}
@@ -157,7 +161,7 @@ class CWMonero extends Monero {
 	}
 
 	@override
-	int getHeigthByDate({DateTime date}) {
+	int getHeigthByDate({required DateTime date}) {
 		return getMoneroHeigthByDate(date: date);
 	}
 	
@@ -167,7 +171,7 @@ class CWMonero extends Monero {
 	}
 
 	@override
-	TransactionPriority deserializeMoneroTransactionPriority({int raw}) {
+	TransactionPriority deserializeMoneroTransactionPriority({required int raw}) {
 		return MoneroTransactionPriority.deserialize(raw: raw);
 	}
 
@@ -206,13 +210,13 @@ class CWMonero extends Monero {
 
 	@override
 	WalletCredentials createMoneroRestoreWalletFromKeysCredentials({
-			String name,
-    	String spendKey,
-    	String viewKey,
-    	String address,
-    	String password,
-    	String language,
-    	int height}) {
+			required String name,
+    	required String spendKey,
+    	required String viewKey,
+    	required String address,
+    	required String password,
+    	required String language,
+    	required int height}) {
 		return MoneroRestoreWalletFromKeysCredentials(
 			name: name,
 			spendKey: spendKey,
@@ -224,7 +228,11 @@ class CWMonero extends Monero {
 	}
 	
 	@override
-	WalletCredentials createMoneroRestoreWalletFromSeedCredentials({String name, String password, int height, String mnemonic}) {
+	WalletCredentials createMoneroRestoreWalletFromSeedCredentials({
+    required String name,
+    required String password,
+    required int height,
+    required String mnemonic}) {
 		return MoneroRestoreWalletFromSeedCredentials(
 			name: name,
 			password: password,
@@ -233,7 +241,10 @@ class CWMonero extends Monero {
 	}
 
 	@override
-	WalletCredentials createMoneroNewWalletCredentials({String name, String password, String language}) {
+	WalletCredentials createMoneroNewWalletCredentials({
+    required String name,
+    required String language,
+    String? password,}) {
 		return MoneroNewWalletCredentials(
 			name: name,
 			password: password,
@@ -252,7 +263,9 @@ class CWMonero extends Monero {
 	}
 
 	@override
-	Object createMoneroTransactionCreationCredentials({List<Output> outputs, TransactionPriority priority}) {
+	Object createMoneroTransactionCreationCredentials({
+    required List<Output> outputs,
+    required TransactionPriority priority}) {
 		return MoneroTransactionCreationCredentials(
 			outputs: outputs.map((out) => OutputInfo(
 					fiatAmount: out.fiatAmount,
@@ -268,24 +281,26 @@ class CWMonero extends Monero {
 	}
 
 	@override
-	Object createMoneroTransactionCreationCredentialsRaw({List<OutputInfo> outputs, TransactionPriority priority}) {
+	Object createMoneroTransactionCreationCredentialsRaw({
+    required List<OutputInfo> outputs,
+    required TransactionPriority priority}) {
 		return MoneroTransactionCreationCredentials(
 			outputs: outputs,
 			priority: priority as MoneroTransactionPriority);
 	}
 
 	@override
-	String formatterMoneroAmountToString({int amount}) {
+	String formatterMoneroAmountToString({required int amount}) {
 		return moneroAmountToString(amount: amount);
 	}
 
 	@override
-	double formatterMoneroAmountToDouble({int amount}) {
+	double formatterMoneroAmountToDouble({required int amount}) {
 		return moneroAmountToDouble(amount: amount);
 	}
 
 	@override
-	int formatterMoneroParseAmount({String amount}) {
+	int formatterMoneroParseAmount({required String amount}) {
 		return moneroParseAmount(amount: amount);
 	}
 
@@ -293,7 +308,7 @@ class CWMonero extends Monero {
 	Account getCurrentAccount(Object wallet) {
 		final moneroWallet = wallet as MoneroWallet;
 		final acc = moneroWallet.walletAddresses.account;
-		return Account(id: acc.id, label: acc.label);
+		return Account(id: acc!.id, label: acc.label);
 	}
 
 	@override