Small fixes to the Sell feature

lib/buy/onramper/onramper_buy_provider.dart

@@ -40,6 +40,8 @@ class OnRamperBuyProvider extends BuyProvider {
 
   String? recommendedPaymentType;
 
+  FiatCurrency? recommendedFiat;
+
   String get _apiKey => secrets.onramperApiKey;
 
   String get _exchangeHelperApiKey => secrets.exchangeHelperApiKey;
@@ -76,7 +78,7 @@ class OnRamperBuyProvider extends BuyProvider {
     }
   }
 
-  Future<String?> getRecommendedPaymentType(bool isBuyAction) async {
+  Future<void> fetchRecommendedDefaults(bool isBuyAction) async {
     final params = {'type': isBuyAction ? 'buy' : 'sell'};
 
     final url = Uri.https(_baseApiUrl, '$supported$defaultsAll', params);
@@ -91,21 +93,26 @@ class OnRamperBuyProvider extends BuyProvider {
         final Map<String, dynamic> data = jsonDecode(response.body) as Map<String, dynamic>;
         final recommended = data['message']['recommended'] as Map<String, dynamic>;
 
-        final recommendedPaymentType = recommended['paymentMethod'] as String?;
+        recommendedPaymentType = recommended['paymentMethod'] as String?;
 
-        return recommendedPaymentType;
+        // the recommendation is a source -> target pair, so which side is the
+        // fiat one flips with the action
+        final fiat = recommended[isBuyAction ? 'source' : 'target'] as String?;
+        recommendedFiat =
+            fiat == null ? null : FiatCurrency.tryDeserialize(raw: fiat.toUpperCase());
       } else {
         final responseBody = jsonDecode(response.body) as Map<String, dynamic>;
-        printV('Failed to fetch available payment types: ${responseBody['message']}');
+        printV('Failed to fetch recommended defaults: ${responseBody['message']}');
       }
     } catch (e) {
-      printV('Failed to fetch available payment types: $e');
+      printV('Failed to fetch recommended defaults: $e');
     }
-    return null;
   }
 
   Future<List<PaymentMethod>> getAvailablePaymentTypes(
       String fiatCurrency, CryptoCurrency cryptoCurrency, bool isBuyAction) async {
+    await fetchRecommendedDefaults(isBuyAction);
+
     final normalizedCryptoCurrency = cryptoCurrency.title + _getNormalizeNetwork(cryptoCurrency);
 
     final sourceCurrency = (isBuyAction ? fiatCurrency : normalizedCryptoCurrency).toLowerCase();
@@ -128,8 +135,6 @@ class OnRamperBuyProvider extends BuyProvider {
             .map((item) => PaymentMethod.fromOnramperJson(item as Map<String, dynamic>))
             .toList();
 
-        recommendedPaymentType = await getRecommendedPaymentType(isBuyAction);
-
         return allAvailablePaymentMethods;
       } else {
         final responseBody = jsonDecode(response.body) as Map<String, dynamic>;

lib/buy/sell_buy_states.dart

@@ -17,7 +17,7 @@ class BuySellQuotLoading extends BuySellQuotLoadingState {}
 class BuySellQuotLoaded extends BuySellQuotLoadingState {}
 
 class BuySellQuotFailed extends BuySellQuotLoadingState {
-  final String? errorMessage;
+  final String errorMessage;
 
-  BuySellQuotFailed({this.errorMessage});
+  BuySellQuotFailed({required this.errorMessage});
 }

lib/entities/fiat_currency.dart

@@ -270,6 +270,8 @@ class FiatCurrency extends EnumerableItem<String> with Serializable<String> impl
 
   static FiatCurrency deserialize({required String raw}) => _all[raw] ?? FiatCurrency.usd;
 
+  static FiatCurrency? tryDeserialize({required String raw}) => _all[raw];
+
   @override
   bool operator ==(Object other) => other is FiatCurrency && other.raw == raw;
 

lib/new-ui/pages/buy_sell/buy_sell_provider_page.dart

@@ -1,12 +1,14 @@
 import "package:cake_wallet/buy/buy_quote.dart";
 import "package:cake_wallet/buy/sell_buy_states.dart";
+import "package:cake_wallet/entities/fiat_currency.dart";
 import "package:cake_wallet/entities/new_ui_entities/list_item/list_item.dart";
 import "package:cake_wallet/entities/new_ui_entities/list_item/list_item_dropdown.dart";
 import "package:cake_wallet/entities/new_ui_entities/list_item/list_item_regular_row.dart";
 import "package:cake_wallet/generated/i18n.dart";
 import "package:cake_wallet/new-ui/pages/buy_sell/buy_sell_confirmation_page.dart";
 import "package:cake_wallet/new-ui/pages/buy_sell/buy_sell_payment_method_page.dart";
 import "package:cake_wallet/new-ui/widgets/money/money_text.dart";
+import "package:cake_wallet/new-ui/widgets/new_primary_button.dart";
 import "package:cake_wallet/new-ui/widgets/receive_page/receive_top_bar.dart";
 import "package:cake_wallet/src/widgets/new_list_row/new_list_section.dart";
 import "package:cake_wallet/view_model/buy/buy_sell_view_model.dart";
@@ -52,31 +54,8 @@ class _BuySellProviderPageState extends State<BuySellProviderPage> {
               Expanded(
                 child: Observer(
                   builder: (_) {
-                    if (widget.buySellViewModel.buySellQuotState is BuySellQuotFailed) {
-                      return Column(
-                        mainAxisAlignment: MainAxisAlignment.center,
-                        spacing: 24,
-                        children: [
-                          const Icon(Icons.warning_amber_outlined, size: 48),
-                          Column(
-                            spacing: 10,
-                            children: [
-                              Text(
-                                S.of(context).could_not_load_quotes,
-                                style: const TextStyle(fontSize: 20, fontWeight: FontWeight.w500),
-                              ),
-                              Text(
-                                (widget.buySellViewModel.buySellQuotState as BuySellQuotFailed)
-                                        .errorMessage ??
-                                    S.of(context).please_try_again_later,
-                              ),
-                            ],
-                          ),
-                        ],
-                      );
-                    }
-
-                    if (widget.buySellViewModel.buySellQuotState is BuySellQuotLoading) {
+                    if (widget.buySellViewModel.buySellQuotState is BuySellQuotLoading ||
+                        widget.buySellViewModel.buySellQuotState is InitialBuySellQuotState) {
                       return Center(
                         child: Row(
                           mainAxisAlignment: MainAxisAlignment.center,
@@ -93,6 +72,18 @@ class _BuySellProviderPageState extends State<BuySellProviderPage> {
                       );
                     }
 
+                    if (widget.buySellViewModel.buySellQuotState is BuySellQuotFailed) {
+                      final recommendedFiat = widget.buySellViewModel.recommendedFiat;
+
+                      return BuySellQuoteFailure(
+                        state: widget.buySellViewModel.buySellQuotState as BuySellQuotFailed,
+                        recommendedFiat: recommendedFiat == widget.buySellViewModel.fiatCurrency
+                            ? null
+                            : recommendedFiat,
+                        onRetryPressed: widget.buySellViewModel.retryWithRecommendedFiat,
+                      );
+                    }
+
                     return SingleChildScrollView(
                       controller: ModalScrollController.of(context),
                       child: Padding(
@@ -195,3 +186,54 @@ class _BuySellProviderPageState extends State<BuySellProviderPage> {
     );
   }
 }
+
+class BuySellQuoteFailure extends StatelessWidget {
+  const BuySellQuoteFailure({
+    required this.state,
+    required this.onRetryPressed,
+    super.key,
+    this.recommendedFiat,
+  });
+
+  final BuySellQuotFailed state;
+  final FiatCurrency? recommendedFiat;
+  final VoidCallback onRetryPressed;
+
+  @override
+  Widget build(BuildContext context) {
+    final recommendedFiat = this.recommendedFiat;
+
+    return Padding(
+      padding: const EdgeInsets.symmetric(horizontal: 18),
+      child: Column(
+        mainAxisAlignment: MainAxisAlignment.center,
+        spacing: 24,
+        children: [
+          const Icon(Icons.warning_amber_outlined, size: 48),
+          Column(
+            spacing: 10,
+            children: [
+              Text(
+                S.of(context).could_not_load_quotes,
+                style: const TextStyle(fontSize: 20, fontWeight: FontWeight.w500),
+              ),
+              Text(
+                recommendedFiat == null
+                    ? state.errorMessage
+                    : S.of(context).providers_in_region_use_fiat(recommendedFiat.title),
+                textAlign: TextAlign.center,
+              ),
+            ],
+          ),
+          if (recommendedFiat != null)
+            NewPrimaryButton(
+              onPressed: onRetryPressed,
+              text: S.of(context).switch_to_fiat(recommendedFiat.title),
+              color: Theme.of(context).colorScheme.primary,
+              textColor: Theme.of(context).colorScheme.onPrimary,
+            ),
+        ],
+      ),
+    );
+  }
+}