add general balance model to reduce clutter

lib/models/balance.dart

@@ -0,0 +1,39 @@
+import 'package:decimal/decimal.dart';
+import 'package:stackwallet/utilities/enums/coin_enum.dart';
+import 'package:stackwallet/utilities/format.dart';
+
+class Balance {
+  final Coin coin;
+  final int total;
+  final int spendable;
+  final int blockedTotal;
+  final int pendingSpendable;
+
+  Balance({
+    required this.coin,
+    required this.total,
+    required this.spendable,
+    required this.blockedTotal,
+    required this.pendingSpendable,
+  });
+
+  Decimal getTotal({bool includeBlocked = false}) => Format.satoshisToAmount(
+        includeBlocked ? total : total - blockedTotal,
+        coin: coin,
+      );
+
+  Decimal getSpendable() => Format.satoshisToAmount(
+        spendable,
+        coin: coin,
+      );
+
+  Decimal getPending() => Format.satoshisToAmount(
+        pendingSpendable,
+        coin: coin,
+      );
+
+  Decimal getBlocked() => Format.satoshisToAmount(
+        blockedTotal,
+        coin: coin,
+      );
+}