Use baseunit provider (#3582)

* feat: introduce BaseUnit provider for money settings with aspect-based notifications and add unit tests

* test: expand use_base_unit_provider_test with comprehensive scenarios for BaseUnitConfig behaviors

lib/new-ui/widgets/money/money_settings_provider.dart

@@ -1,15 +1,20 @@
 import "package:cake_wallet/new-ui/widgets/money/money_settings_cubit.dart";
+import "package:cake_wallet/new-ui/widgets/money/use_base_unit_provider.dart";
 import "package:cake_wallet/store/settings_store.dart";
 import "package:flutter/material.dart";
 import "package:flutter_bloc/flutter_bloc.dart";
 
 class MoneySettingsProvider extends StatelessWidget {
-  const MoneySettingsProvider({required this.settingsStore, this.child, super.key});
+  const MoneySettingsProvider({required this.settingsStore, required this.child, super.key});
 
-  final Widget? child;
+  final Widget child;
   final SettingsStore settingsStore;
 
   @override
-  Widget build(BuildContext context) =>
-      BlocProvider(create: (_) => MoneySettingsCubit(settingsStore), child: child);
+  Widget build(BuildContext context) => BlocProvider(
+        create: (_) => MoneySettingsCubit(settingsStore),
+        child: BaseUnitScope(
+          child: child,
+        ),
+      );
 }

lib/new-ui/widgets/money/use_base_unit_provider.dart

@@ -0,0 +1,63 @@
+import "dart:async";
+
+import "package:cake_wallet/new-ui/widgets/money/money_settings_cubit.dart";
+import "package:cw_core/currency.dart";
+import "package:flutter/widgets.dart";
+import "package:flutter_bloc/flutter_bloc.dart";
+
+/// Read-only view of the money display settings for the current subtree.
+///
+/// ```dart
+/// final useBaseUnit = BaseUnit.useBaseUnitOf(context, CryptoCurrency.btc);
+/// ```
+class BaseUnit extends InheritedModel<Currency> {
+  const BaseUnit({required this.state, required super.child});
+
+  final MoneySettingsState state;
+
+  static bool useBaseUnitOf(BuildContext context, Currency currency) =>
+      InheritedModel.inheritFrom<BaseUnit>(context, aspect: currency)!.state.useBaseUnit(currency);
+
+  static String getSymbolOf(BuildContext context, Currency currency) =>
+      InheritedModel.inheritFrom<BaseUnit>(context, aspect: currency)!.state.getSymbol(currency);
+
+  @override
+  bool updateShouldNotify(BaseUnit old) =>
+      state.bitcoinAmountDisplayMode != old.state.bitcoinAmountDisplayMode;
+
+  @override
+  bool updateShouldNotifyDependent(BaseUnit old, Set<Currency> aspects) => aspects.any((c) =>
+      state.useBaseUnit(c) != old.state.useBaseUnit(c) ||
+      state.getSymbol(c) != old.state.getSymbol(c));
+}
+
+class BaseUnitScope extends StatefulWidget {
+  const BaseUnitScope({required this.child, super.key});
+
+  final Widget child;
+
+  @override
+  State<BaseUnitScope> createState() => _BaseUnitScopeState();
+}
+
+class _BaseUnitScopeState extends State<BaseUnitScope> {
+  late MoneySettingsState _state;
+  late final StreamSubscription<MoneySettingsState> _sub;
+
+  @override
+  void initState() {
+    super.initState();
+    final cubit = context.read<MoneySettingsCubit>();
+    _state = cubit.state;
+    _sub = cubit.stream.listen((s) => setState(() => _state = s));
+  }
+
+  @override
+  void dispose() {
+    _sub.cancel();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) => BaseUnit(state: _state, child: widget.child);
+}