CW-254-proper-bitcoin-address-validation-in-exchange-screen (#900)

* feat: Proper Bitcoin address validation in exchange screen

* fix: use custom validation in addition to RegEx to make sure all address cases are validated

- for cases like P2SH addresses starting with a 3, which are not validated by bitcoin_flutter functions

* feat: add bitcoin_flutter to root project

* refactor: improve conditional isValid return chain

lib/core/address_validator.dart

@@ -1,4 +1,4 @@
-import 'package:flutter/foundation.dart';
+import 'package:bitcoin_flutter/bitcoin_flutter.dart' as bitcoin;
 import 'package:cake_wallet/generated/i18n.dart';
 import 'package:cake_wallet/core/validator.dart';
 import 'package:cw_core/crypto_currency.dart';
@@ -7,6 +7,9 @@ class AddressValidator extends TextValidator {
   AddressValidator({required CryptoCurrency type})
       : super(
             errorMessage: S.current.error_text_address,
+            useAdditionalValidation: type == CryptoCurrency.btc
+                ? bitcoin.Address.validateAddress
+                : null,
             pattern: getPattern(type),
             length: getLength(type));
 
@@ -18,8 +21,7 @@ class AddressValidator extends TextValidator {
         return '^[0-9a-zA-Z]{59}\$|^[0-9a-zA-Z]{92}\$|^[0-9a-zA-Z]{104}\$'
             '|^[0-9a-zA-Z]{105}\$|^addr1[0-9a-zA-Z]{98}\$';
       case CryptoCurrency.btc:
-        return '^1[0-9a-zA-Z]{32}\$|^1[0-9a-zA-Z]{33}\$|^3[0-9a-zA-Z]{32}\$'
-            '|^3[0-9a-zA-Z]{33}\$|^bc1[0-9a-zA-Z]{39}\$|^bc1[0-9a-zA-Z]{59}\$';
+        return '^3[0-9a-zA-Z]{32}\$|^3[0-9a-zA-Z]{33}\$|^bc1[0-9a-zA-Z]{59}\$';
       case CryptoCurrency.nano:
         return '[0-9a-zA-Z_]';
       case CryptoCurrency.usdc:

lib/core/validator.dart

@@ -1,9 +1,8 @@
-import 'package:flutter/foundation.dart';
-
 abstract class Validator<T> {
-  Validator({required this.errorMessage});
+  Validator({required this.errorMessage, this.useAdditionalValidation});
 
   final String errorMessage;
+  final bool Function(T)? useAdditionalValidation;
 
   bool isValid(T? value);
 
@@ -11,14 +10,17 @@ abstract class Validator<T> {
 }
 
 class TextValidator extends Validator<String> {
-  TextValidator(
-      {this.minLength,
+  TextValidator({
+    bool Function(String)? useAdditionalValidation,
+    this.minLength,
     this.maxLength,
     this.pattern,
     String errorMessage = '',
     this.length,
-      this.isAutovalidate = false})
-      : super(errorMessage: errorMessage);
+    this.isAutovalidate = false,
+  }) : super(
+            errorMessage: errorMessage,
+            useAdditionalValidation: useAdditionalValidation);
 
   final int? minLength;
   final int? maxLength;
@@ -32,11 +34,26 @@ class TextValidator extends Validator<String> {
       return isAutovalidate ? true : false;
     }
 
-    return value.length > (minLength ?? 0) &&
-        (length?.contains(value.length) ?? true) &&
-        ((maxLength ?? 0) > 0 ? (value.length <= maxLength!) : true) &&
-        (pattern != null ? match(value) : true);
+    final greaterThanMinLength = value.length > (minLength ?? 0);
+    if (!greaterThanMinLength) return false;
+
+    final lengthMatched = length?.contains(value.length) ?? true;
+    if (!lengthMatched) return false;
+
+    final lowerThanMaxLength =
+        (maxLength ?? 0) > 0 ? (value.length <= maxLength!) : true;
+    if (!lowerThanMaxLength) return false;
+
+    if (pattern == null) return true;
+
+    final valueMatched = match(value);
+    final valueValidated = useAdditionalValidation != null
+        ? useAdditionalValidation!(value) || valueMatched
+        : valueMatched;
+
+    return valueValidated;
   }
 
-  bool match(String value) => pattern != null ? RegExp(pattern!).hasMatch(value) : false;
+  bool match(String value) =>
+      pattern != null ? RegExp(pattern!).hasMatch(value) : false;
 }

pubspec_base.yaml

@@ -81,6 +81,10 @@ dependencies:
   path_provider_android: 2.0.24
   shared_preferences_android: 2.0.17
   url_launcher_android: 6.0.24
+  bitcoin_flutter:
+    git:
+      url: https://github.com/cake-tech/bitcoin_flutter.git
+      ref: cake-update-v2
 
 dev_dependencies:
   flutter_test: