Add null handling to AccountState.fromJson

Save BigInt's as string

Set isInitial default value to true

lib/cubit/account/account_state.dart

@@ -1,6 +1,9 @@
 import 'dart:convert';
 
 import 'package:breez_liquid/breez_liquid.dart';
+import 'package:logging/logging.dart';
+
+final _log = Logger("AccountState");
 
 class AccountState {
   final bool isInitial;
@@ -31,7 +34,7 @@ class AccountState {
 
   factory AccountState.fromJson(Map<String, dynamic> json) {
     return AccountState(
-      isInitial: json["isInitial"],
+      isInitial: json["isInitial"] ?? true,
       walletInfo: GetInfoResponseFromJson.fromJson(json['walletInfo']),
     );
   }
@@ -43,17 +46,31 @@ class AccountState {
 extension GetInfoResponseToJson on GetInfoResponse {
   Map<String, dynamic> toJson() {
     return {
-      'balanceSat': balanceSat,
-      'pendingSendSat': pendingSendSat,
-      'pendingReceiveSat': pendingReceiveSat,
+      'balanceSat': balanceSat.toString(),
+      'pendingSendSat': pendingSendSat.toString(),
+      'pendingReceiveSat': pendingReceiveSat.toString(),
       'fingerprint': fingerprint,
       'pubkey': pubkey,
     };
   }
 }
 
 extension GetInfoResponseFromJson on GetInfoResponse {
-  static GetInfoResponse fromJson(Map<String, dynamic> json) {
+  static GetInfoResponse? fromJson(Map<String, dynamic>? json) {
+    if (json == null) {
+      _log.info("walletInfo is missing from AccountState JSON.");
+      return null;
+    }
+
+    if (json['balanceSat'] == null ||
+        json['pendingSendSat'] == null ||
+        json['pendingReceiveSat'] == null ||
+        json['fingerprint'] == null ||
+        json['pubkey'] == null) {
+      _log.warning("GetInfoResponse has missing fields on AccountState JSON.");
+      return null;
+    }
+
     return GetInfoResponse(
       balanceSat: BigInt.parse(json['balanceSat'] as String),
       pendingSendSat: BigInt.parse(json['pendingSendSat'] as String),