feat: cache usdc balance (#1348)

Co-authored-by: ookami-kb <[email protected]>
espresso-cash · Mar 30, 2024 · 8b4948a · 8b4948a
1 parent 7c90034
commit 8b4948a
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Showing 5 changed files with 75 additions and 27 deletions.
diff --git a/packages/espressocash_app/lib/features/authenticated/widgets/investment_header.dart b/packages/espressocash_app/lib/features/authenticated/widgets/investment_header.dart
@@ -64,14 +64,8 @@ class _Buttons extends StatelessWidget {
   Widget build(BuildContext context) => DecoratedBox(
         decoration: const BoxDecoration(color: Color(0xff202020)),
         child: ValueStreamBuilder<bool>(
-          create: () => (
-            sl<WatchUserFiatBalance>()
-                .call()
-                .$1
-                .map((event) => event ?? Amount.zero(currency: Currency.usd))
-                .map((event) => event.isZero),
-            true,
-          ),
+          create: () =>
+              sl<WatchUserFiatBalance>().call().map((it) => it.isZero),
           builder: (context, isZeroAmount) => Padding(
             padding: const EdgeInsets.symmetric(vertical: 12, horizontal: 18),
             child: Column(
@@ -169,13 +163,7 @@ class _Amount extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) => ValueStreamBuilder<Amount>(
-        create: () => (
-          sl<WatchUserFiatBalance>()
-              .call()
-              .$1
-              .map((event) => event ?? Amount.zero(currency: Currency.usd)),
-          Amount.zero(currency: Currency.usd),
-        ),
+        create: () => sl<WatchUserFiatBalance>().call(),
         builder: (context, amount) {
           final formattedAmount = amount.format(
             DeviceLocale.localeOf(context),

diff --git a/packages/espressocash_app/lib/features/balances/data/balances_repository.dart b/packages/espressocash_app/lib/features/balances/data/balances_repository.dart
@@ -1,12 +1,34 @@
+import 'dart:async';
+
 import 'package:espressocash_common/espressocash_common.dart';
 import 'package:flutter/material.dart';
 import 'package:injectable/injectable.dart';
 import 'package:rxdart/rxdart.dart';
+import 'package:shared_preferences/shared_preferences.dart';
 
 import '../../authenticated/auth_scope.dart';
 
 @Singleton(scope: authScope)
 class BalancesRepository extends ChangeNotifier {
+  BalancesRepository(this._storage);
+
+  final SharedPreferences _storage;
+
+  @PostConstruct()
+  void init() {
+    final balance = _storage.getInt(_usdcBalanceKey);
+
+    if (balance == null) return;
+
+    _usdcBalance.add(
+      CryptoAmount(
+        value: balance,
+        cryptoCurrency: const CryptoCurrency(token: Token.usdc),
+      ),
+    );
+    notifyListeners();
+  }
+
   final _usdcBalance = BehaviorSubject<CryptoAmount>.seeded(
     const CryptoAmount(
       value: 0,
@@ -20,6 +42,7 @@ class BalancesRepository extends ChangeNotifier {
     }
 
     _usdcBalance.add(balance);
+    _storage.setInt(_usdcBalanceKey, balance.value);
     notifyListeners();
   }
 
@@ -28,8 +51,12 @@ class BalancesRepository extends ChangeNotifier {
   (Stream<CryptoAmount>, CryptoAmount) watch() => (_usdcBalance.stream, read());
 
   @override
+  @disposeMethod
   void dispose() {
     _usdcBalance.close();
+    _storage.remove(_usdcBalanceKey);
     super.dispose();
   }
 }
+
+const _usdcBalanceKey = 'usdcBalance';
diff --git a/packages/espressocash_app/lib/features/conversion_rates/data/repository.dart b/packages/espressocash_app/lib/features/conversion_rates/data/repository.dart
@@ -5,19 +5,38 @@ import 'package:fast_immutable_collections/fast_immutable_collections.dart';
 import 'package:flutter/material.dart';
 import 'package:injectable/injectable.dart';
 import 'package:rxdart/rxdart.dart';
+import 'package:shared_preferences/shared_preferences.dart';
 
+import '../../authenticated/auth_scope.dart';
 import 'conversion_rates_client.dart';
 
-@lazySingleton
+@Singleton(scope: authScope)
 class ConversionRatesRepository extends ChangeNotifier {
   ConversionRatesRepository({
+    required SharedPreferences storage,
     required ConversionRatesClient coingeckoClient,
-  }) : _coingeckoClient = coingeckoClient;
+  })  : _coingeckoClient = coingeckoClient,
+        _storage = storage;
 
   final BehaviorSubject<IMap<FiatCurrency, Decimal>> _value =
       BehaviorSubject.seeded(const IMapConst({}));
 
   final ConversionRatesClient _coingeckoClient;
+  final SharedPreferences _storage;
+
+  @PostConstruct()
+  void init() {
+    final rate = _storage.getDouble(_usdcRateKey);
+
+    if (rate == null) return;
+
+    _value.add(
+      IMapConst({
+        Currency.usd: Decimal.tryParse(rate.toString()) ?? Decimal.zero,
+      }),
+    );
+    notifyListeners();
+  }
 
   Decimal? readRate({required FiatCurrency to}) => _value.value[to];
 
@@ -48,6 +67,18 @@ class ConversionRatesRepository extends ChangeNotifier {
         );
 
         _value.add(value);
+        await _storage.setDouble(_usdcRateKey, data.usd ?? 0);
+
         notifyListeners();
       });
+
+  @override
+  @disposeMethod
+  void dispose() {
+    _value.close();
+    _storage.remove(_usdcRateKey);
+    super.dispose();
+  }
 }
+
+const _usdcRateKey = 'usdcRate';
diff --git a/...ages/espressocash_app/lib/features/conversion_rates/services/watch_user_fiat_balance.dart b/...ages/espressocash_app/lib/features/conversion_rates/services/watch_user_fiat_balance.dart
@@ -17,7 +17,7 @@ class WatchUserFiatBalance {
   final ConversionRatesRepository _conversionRatesRepository;
   final BalancesRepository _balancesRepository;
 
-  (Stream<FiatAmount?>, FiatAmount?) call() {
+  (Stream<FiatAmount>, FiatAmount) call() {
     const fiatCurrency = defaultFiatCurrency;
     final conversionRate =
         _conversionRatesRepository.watchRate(to: fiatCurrency);
@@ -28,17 +28,15 @@ class WatchUserFiatBalance {
       Rx.combineLatest2(
         balance.$1,
         conversionRate,
-        (cryptoAmount, rate) {
-          if (rate == null) return null;
-
-          return cryptoAmount.convert(rate: rate, to: fiatCurrency)
-              as FiatAmount;
-        },
+        (cryptoAmount, rate) => rate == null
+            ? const FiatAmount(value: 0, fiatCurrency: Currency.usd)
+            : cryptoAmount.convert(rate: rate, to: fiatCurrency) as FiatAmount,
       ).distinct(),
       _conversionRatesRepository.readRate(to: fiatCurrency)?.let(
-            (rate) =>
-                balance.$2.convert(rate: rate, to: fiatCurrency) as FiatAmount,
-          ),
+                (rate) => balance.$2.convert(rate: rate, to: fiatCurrency)
+                    as FiatAmount,
+              ) ??
+          const FiatAmount(value: 0, fiatCurrency: Currency.usd),
     );
   }
 }
diff --git a/packages/espressocash_app/lib/ui/value_stream_builder.dart b/packages/espressocash_app/lib/ui/value_stream_builder.dart
@@ -3,6 +3,10 @@ import 'package:flutter/widgets.dart';
 typedef ValueWidgetBuilder<T> = Widget Function(BuildContext context, T value);
 typedef ValueStreamFactory<T> = (Stream<T>, T) Function();
 
+extension ValueExt<T> on (Stream<T>, T) {
+  (Stream<U>, U) map<U>(U Function(T value) fn) => ($1.map<U>(fn), fn($2));
+}
+
 class ValueStreamBuilder<T> extends StatefulWidget {
   const ValueStreamBuilder({
     super.key,