feat(#281): currency-aware payment method suggestions in create-order form

assets/data/payment_methods.json

@@ -0,0 +1,31 @@
+{
+  "ARS": ["Mercado Pago", "MODO", "CVU", "Belo", "Lemon", "CBU", "Efectivo"],
+  "AUD": ["PayID", "Alipay", "Cash deposit", "Revolut", "Cash"],
+  "BOB": ["QR", "Transferencia Bancaria", "Efectivo"],
+  "BRL": ["PIX", "TED", "PicPay", "Depósito", "Cash"],
+  "CAD": ["Interac e-Transfer", "Any national bank", "Wise", "Revolut", "Cash"],
+  "CHF": ["TWINT", "Cash"],
+  "CLP": ["MACH", "Cuenta RUT", "Mercado Pago", "Transferencia bancaria", "Efectivo"],
+  "CRC": ["Bank transfer (IBAN)", "SINPE Móvil", "Cash"],
+  "COP": ["Nequi", "Daviplata", "PSE", "Llaves BRE-B", "Transferencia bancaria", "Efectivo"],
+  "CUP": ["Transfermovil", "EnZona", "Tarjeta Clásica", "Saldo móvil", "MiTransfer", "Efectivo"],
+  "EUR": ["Revolut", "HalCash", "Bank Transfer", "Wise", "SEPA instant", "Bizum", "Payoneer", "Cash"],
+  "GBP": ["Revolut", "Monzo", "Wise", "Any national bank", "Bank Transfer", "Cash"],
+  "JPY": ["PayPay", "Bank Transfer", "Cash"],
+  "KES": ["M-PESA", "Equity Bank", "NCBA Bank", "Airtel Money", "Co-operative Bank", "Standard Chartered", "Ecobank", "GTBank", "Pochi la Biashara", "Cash"],
+  "MLC": ["Transfermovil", "EnZona"],
+  "MWK": ["Airtel Money", "TNM Mpamba", "Bank Transfer", "Cash"],
+  "MXN": ["SPEI", "CoDi", "Retiro Cajero BBVA", "Efectivo"],
+  "MZN": ["M-Pesa", "e-Mola", "Millennium bim", "BCI", "Cash"],
+  "NGN": ["OPay", "PalmPay", "Moniepoint", "GTBank", "Access Bank", "UBA", "Zenith Bank", "Bank Transfer", "Cash"],
+  "PEN": ["Yape", "Plin", "QR Yape", "Transferencia bancaria", "Cash"],
+  "PHP": ["Any national bank", "GCash", "Cash"],
+  "PYG": ["SIPAP", "Transferencia bancaria", "Efectivo"],
+  "TZS": ["M-Pesa", "Mixx by Yas (Tigo Pesa)", "Airtel Money", "Halopesa", "CRDB Bank", "Cash"],
+  "UGX": ["MTN MoMo", "Airtel Money", "Chipper Cash", "Cash"],
+  "USD": ["Cash App", "Venmo", "Zelle", "PayPal", "Wise", "Payoneer", "Strike", "Revolut", "N1CO", "Transfer365", "Cash"],
+  "VES": ["Pago Móvil", "Binance P2P", "Transferencia bancaria", "Efectivo"],
+  "ZAR": ["Capitec", "FNB", "Absa", "Nedbank", "Standard Bank", "FNB eWallet", "MTN MoMo", "Cash"],
+  "ZMW": ["Airtel Money", "MTN MoMo", "Zamtel Kwacha", "FNB eWallet", "Stanbic Bank", "SPENN", "Cash"],
+  "default": ["Bank Transfer", "Cash in person"]
+}

lib/features/order/providers/payment_methods_provider.dart

@@ -0,0 +1,36 @@
+import 'dart:convert';
+
+import 'package:flutter/services.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+
+/// The default payment methods used when a currency has no specific list.
+const _fallbackMethods = <String>['Bank Transfer', 'Cash in person'];
+
+/// Loads the currency → payment-methods map from the bundled asset once.
+final paymentMethodsDataProvider =
+    FutureProvider<Map<String, List<String>>>((ref) async {
+  final raw =
+      await rootBundle.loadString('assets/data/payment_methods.json');
+  final decoded = jsonDecode(raw) as Map<String, dynamic>;
+  return decoded.map(
+    (code, methods) => MapEntry(
+      code,
+      (methods as List<dynamic>).cast<String>(),
+    ),
+  );
+});
+
+/// The suggested payment methods for [currencyCode], falling back to the
+/// `default` list (and then a hardcoded fallback) for unknown currencies.
+///
+/// Returns an empty list while the asset is still loading so the section can
+/// render its custom field without flashing placeholder chips.
+final paymentMethodsForCurrencyProvider =
+    Provider.family<List<String>, String>((ref, currencyCode) {
+  final data = ref.watch(paymentMethodsDataProvider);
+  return data.maybeWhen(
+    data: (map) =>
+        map[currencyCode] ?? map['default'] ?? _fallbackMethods,
+    orElse: () => const <String>[],
+  );
+});

lib/features/order/widgets/payment_method_section.dart

@@ -2,22 +2,10 @@ import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 
 import 'package:mostro/core/app_theme.dart';
+import 'package:mostro/features/order/providers/payment_methods_provider.dart';
+import 'package:mostro/features/order/widgets/currency_section.dart';
 import 'package:mostro/l10n/app_localizations.dart';
 
-/// Common payment methods available for selection.
-const _commonMethods = [
-  'Mercado Pago',
-  'Bank Transfer',
-  'Pix',
-  'Zelle',
-  'Wise',
-  'SEPA',
-  'Revolut',
-  'Cash',
-  'PayPal',
-  'Nequi',
-];
-
 /// Selected payment methods for the create-order form.
 final selectedPaymentMethodsProvider =
     StateProvider<List<String>>((_) => []);
@@ -57,6 +45,20 @@ class _PaymentMethodSectionState extends ConsumerState<PaymentMethodSection> {
     final colors = theme.extension<AppColors>();
     final green = colors?.mostroGreen ?? const Color(0xFF8CC63F);
     final inputBg = colors?.backgroundInput ?? const Color(0xFF252A3A);
+    // When the currency changes, drop any selected methods that are not valid
+    // for the new currency (the custom free-text entry is left untouched).
+    ref.listen<String>(selectedFiatCodeProvider, (_, next) {
+      // Don't prune while the asset is still loading: the provider returns an
+      // empty list during load, which would wipe every selection.
+      if (!ref.read(paymentMethodsDataProvider).hasValue) return;
+      final valid = ref.read(paymentMethodsForCurrencyProvider(next)).toSet();
+      final current = ref.read(selectedPaymentMethodsProvider);
+      final pruned = current.where(valid.contains).toList();
+      if (pruned.length != current.length) {
+        ref.read(selectedPaymentMethodsProvider.notifier).state = pruned;
+      }
+    });
+
     final selected = ref.watch(selectedPaymentMethodsProvider);
     final custom = ref.watch(customPaymentMethodProvider);
     final l10n = AppLocalizations.of(context);
@@ -146,12 +148,15 @@ class _PaymentMethodSectionState extends ConsumerState<PaymentMethodSection> {
   void _showMethodPicker(BuildContext context) {
     final selected = ref.read(selectedPaymentMethodsProvider);
 
+    final fiatCode = ref.read(selectedFiatCodeProvider);
+    final methods = ref.read(paymentMethodsForCurrencyProvider(fiatCode));
     showDialog<void>(
       context: context,
       builder: (dialogContext) => _MethodPickerDialog(
         selected: selected,
-        onDone: (methods) {
-          ref.read(selectedPaymentMethodsProvider.notifier).state = methods;
+        methods: methods,
+        onDone: (chosen) {
+          ref.read(selectedPaymentMethodsProvider.notifier).state = chosen;
           Navigator.pop(dialogContext);
         },
       ),
@@ -162,10 +167,12 @@ class _PaymentMethodSectionState extends ConsumerState<PaymentMethodSection> {
 class _MethodPickerDialog extends StatefulWidget {
   const _MethodPickerDialog({
     required this.selected,
+    required this.methods,
     required this.onDone,
   });
 
   final List<String> selected;
+  final List<String> methods;
   final ValueChanged<List<String>> onDone;
 
   @override
@@ -202,7 +209,7 @@ class _MethodPickerDialogState extends State<_MethodPickerDialog> {
             Wrap(
               spacing: AppSpacing.sm,
               runSpacing: AppSpacing.xs,
-              children: _commonMethods.map((method) {
+              children: widget.methods.map((method) {
                 final isSelected = _selected.contains(method);
                 return FilterChip(
                   label: Text(method, style: const TextStyle(fontSize: 12)),

pubspec.yaml

@@ -101,4 +101,5 @@ flutter:
 
   assets:
     - assets/data/fiat.json
+    - assets/data/payment_methods.json
     - assets/images/

test/features/order/providers/payment_methods_provider_test.dart

@@ -0,0 +1,65 @@
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:mostro/features/order/providers/payment_methods_provider.dart';
+
+/// In-memory data used to exercise the currency provider without touching
+/// rootBundle (which isn't wired for plain unit tests).
+const _fixture = <String, List<String>>{
+  'ARS': ['Mercado Pago', 'CVU'],
+  'default': ['Bank Transfer', 'Cash in person'],
+};
+
+ProviderContainer _containerWith(Map<String, List<String>> data) {
+  final c = ProviderContainer(overrides: [
+    paymentMethodsDataProvider.overrideWith((ref) async => data),
+  ]);
+  addTearDown(c.dispose);
+  return c;
+}
+
+void main() {
+  group('paymentMethodsForCurrencyProvider', () {
+    test('returns the currency-specific list for a known currency', () async {
+      final c = _containerWith(_fixture);
+      await c.read(paymentMethodsDataProvider.future);
+      expect(c.read(paymentMethodsForCurrencyProvider('ARS')),
+          ['Mercado Pago', 'CVU']);
+    });
+
+    test('falls back to the default list for an unknown currency', () async {
+      final c = _containerWith(_fixture);
+      await c.read(paymentMethodsDataProvider.future);
+      expect(c.read(paymentMethodsForCurrencyProvider('XXX')),
+          ['Bank Transfer', 'Cash in person']);
+    });
+
+    test('returns an empty list while the asset is still loading', () {
+      final c = _containerWith(_fixture);
+      // Not awaited: the future is still pending, so the provider must yield [].
+      expect(c.read(paymentMethodsForCurrencyProvider('ARS')), isEmpty);
+    });
+  });
+
+  group('shipped payment_methods.json contract', () {
+    late Map<String, dynamic> shipped;
+    setUpAll(() {
+      shipped = jsonDecode(
+        File('assets/data/payment_methods.json').readAsStringSync(),
+      ) as Map<String, dynamic>;
+    });
+
+    test('ships a default fallback plus many currencies', () {
+      expect(shipped.containsKey('default'), isTrue);
+      expect(shipped.length, greaterThan(20));
+    });
+
+    test('known currencies carry their expected local methods', () {
+      expect((shipped['ARS'] as List).cast<String>(), contains('Mercado Pago'));
+      expect((shipped['MWK'] as List).cast<String>(), contains('Airtel Money'));
+      expect((shipped['KES'] as List).cast<String>(), contains('M-PESA'));
+    });
+  });
+}