feat: 5201 - change currency with country when relevant

packages/smooth_app/lib/l10n/app_en.arb

@@ -802,6 +802,24 @@
     "@currency_chooser_label": {
         "description": "Label shown above a selector where the user can select their currency (in the preferences)"
     },
+    "country_change_message": "You have just changed countries.",
+    "@country_change_message": {
+        "description": "Message stating the change of countries"
+    },
+    "currency_auto_change_message": "Do you want to change the currency from {previousCurrency} to {possibleCurrency}?",
+    "@currency_auto_change_message": {
+        "description": "Message asking to confirm the change of currencies",
+        "placeholders": {
+            "previousCurrency": {
+                "type": "String",
+                "description": "Current currency"
+            },
+            "possibleCurrency": {
+                "type": "String",
+                "description": "Possible currency"
+            }
+        }
+    },
     "onboarding_country_chooser_label": "Please choose a country:",
     "@onboarding_country_chooser_label": {
         "description": "The label shown above a selector where the user can select their country (in the onboarding)"

packages/smooth_app/lib/pages/onboarding/country_selector.dart

@@ -18,12 +18,14 @@ class CountrySelector extends StatefulWidget {
     this.padding,
     this.icon,
     this.inkWellBorderRadius,
+    required this.forceCurrencyChange,
   });
 
   final TextStyle? textStyle;
   final EdgeInsetsGeometry? padding;
   final BorderRadius? inkWellBorderRadius;
   final Widget? icon;
+  final bool forceCurrencyChange;
 
   @override
   State<CountrySelector> createState() => _CountrySelectorState();
@@ -168,6 +170,13 @@ class _CountrySelectorState extends State<CountrySelector> {
                     userPreferences,
                     country.countryCode,
                   );
+                  if (context.mounted) {
+                    await _changeCurrencyIfRelevant(
+                      country,
+                      userPreferences,
+                      context,
+                    );
+                  }
                 }
               },
               child: DecoratedBox(
@@ -301,4 +310,50 @@ class _CountrySelectorState extends State<CountrySelector> {
     _countryController.dispose();
     super.dispose();
   }
+
+  Future<void> _changeCurrencyIfRelevant(
+    final Country country,
+    final UserPreferences userPreferences,
+    final BuildContext context,
+  ) async {
+    final OpenFoodFactsCountry? offCountry =
+        OpenFoodFactsCountry.fromOffTag(country.countryCode);
+    final String? possibleCurrencyCode = offCountry?.currency?.name;
+    if (possibleCurrencyCode == null) {
+      return;
+    }
+    bool? changeCurrency;
+    final String? currentCurrencyCode = userPreferences.userCurrencyCode;
+    if (currentCurrencyCode == null) {
+      changeCurrency = true;
+    } else if (widget.forceCurrencyChange) {
+      changeCurrency = true;
+    } else if (currentCurrencyCode != possibleCurrencyCode) {
+      final AppLocalizations appLocalizations = AppLocalizations.of(context);
+      changeCurrency = await showDialog<bool>(
+        context: context,
+        builder: (final BuildContext context) => SmoothAlertDialog(
+          body: Text(
+            '${appLocalizations.country_change_message}'
+            '\n'
+            '${appLocalizations.currency_auto_change_message(
+              currentCurrencyCode,
+              possibleCurrencyCode,
+            )}',
+          ),
+          negativeAction: SmoothActionButton(
+            onPressed: () => Navigator.of(context).pop(),
+            text: appLocalizations.no,
+          ),
+          positiveAction: SmoothActionButton(
+            onPressed: () => Navigator.of(context).pop(true),
+            text: appLocalizations.yes,
+          ),
+        ),
+      );
+    }
+    if (changeCurrency == true) {
+      await userPreferences.setUserCurrencyCode(possibleCurrencyCode);
+    }
+  }
 }

packages/smooth_app/lib/pages/onboarding/welcome_page.dart

@@ -93,6 +93,7 @@ class WelcomePage extends StatelessWidget {
                           child: SizedBox(
                             width: double.infinity,
                             child: CountrySelector(
+                              forceCurrencyChange: true,
                               padding: const EdgeInsets.symmetric(
                                 horizontal: SMALL_SPACE,
                               ),

packages/smooth_app/lib/pages/preferences/user_preferences_country_selector.dart

@@ -34,6 +34,7 @@ class UserPreferencesCountrySelector extends StatelessWidget {
           bottom: SMALL_SPACE,
         ),
         child: CountrySelector(
+          forceCurrencyChange: false,
           textStyle: themeData.textTheme.bodyMedium,
           icon: const Icon(Icons.edit),
           padding: const EdgeInsetsDirectional.only(

packages/smooth_app/lib/query/product_query.dart

@@ -67,6 +67,13 @@ abstract class ProductQuery {
     final OpenFoodFactsCountry country =
         OpenFoodFactsCountry.fromOffTag(isoCode) ?? defaultCountry;
     await _setCountry(userPreferences, country);
+    if (userPreferences.userCurrencyCode == null) {
+      // very very first time, or old app with new code
+      final Currency? possibleCurrency = country.currency;
+      if (possibleCurrency != null) {
+        await userPreferences.setUserCurrencyCode(possibleCurrency.name);
+      }
+    }
   }
 
   /// Sets the global country for API queries: explicit choice by the user.