chore: reload activity suggestions on language update (#2349)

lib/pangea/activity_suggestions/activity_suggestions_area.dart

@@ -1,6 +1,8 @@
 // shows n rows of activity suggestions vertically, where n is the number of rows
 // as the user tries to scroll horizontally to the right, the client will fetch more activity suggestions
 
+import 'dart:async';
+
 import 'package:flutter/material.dart';
 
 import 'package:flutter_gen/gen_l10n/l10n.dart';
@@ -39,15 +41,29 @@ class ActivitySuggestionsArea extends StatefulWidget {
 }
 
 class ActivitySuggestionsAreaState extends State<ActivitySuggestionsArea> {
+  StreamSubscription? _languageStream;
+
   @override
   void initState() {
     super.initState();
     _setActivityItems();
+
+    _languageStream ??= MatrixState.pangeaController.userController.stateStream
+        .listen((update) {
+      if (update is Map<String, dynamic> &&
+          (update.containsKey('prev_base_lang') ||
+              update.containsKey('prev_target_lang'))) {
+        WidgetsBinding.instance.addPostFrameCallback(
+          (_) => _setActivityItems(),
+        );
+      }
+    });
   }
 
   @override
   void dispose() {
     _scrollController.dispose();
+    _languageStream?.cancel();
     super.dispose();
   }
 
@@ -59,18 +75,28 @@ class ActivitySuggestionsAreaState extends State<ActivitySuggestionsArea> {
   double get cardHeight => _isColumnMode ? 325.0 : 250.0;
   double get cardWidth => _isColumnMode ? 225.0 : 150.0;
 
+  String get instructionLanguage =>
+      MatrixState.pangeaController.languageController.userL1?.langCode ??
+      LanguageKeys.defaultLanguage;
+  String get targetLanguage =>
+      MatrixState.pangeaController.languageController.userL2?.langCode ??
+      LanguageKeys.defaultLanguage;
+
   Future<void> _setActivityItems() async {
     try {
+      setState(() {
+        _activityItems.clear();
+        _loading = true;
+      });
+
       final ActivityPlanRequest request = ActivityPlanRequest(
         topic: "",
         mode: "",
         objective: "",
         media: MediaEnum.nan,
         cefrLevel: LanguageLevelTypeEnum.a1,
-        languageOfInstructions: LanguageKeys.defaultLanguage,
-        targetLanguage:
-            MatrixState.pangeaController.languageController.userL2?.langCode ??
-                LanguageKeys.defaultLanguage,
+        languageOfInstructions: instructionLanguage,
+        targetLanguage: targetLanguage,
         numberOfParticipants: 3,
         count: 5,
       );

lib/pangea/user/controllers/user_controller.dart

@@ -82,14 +82,24 @@ class UserController extends BaseController {
     waitForDataInSync = false,
   }) async {
     final prevTargetLang = _pangeaController.languageController.userL2;
+    final prevBaseLang = _pangeaController.languageController.userL1;
 
     final Profile updatedProfile = update(profile);
     await updatedProfile.saveProfileData(waitForDataInSync: waitForDataInSync);
-    setState(
-      prevTargetLang != _pangeaController.languageController.userL2
-          ? {'prev_target_lang': prevTargetLang}
-          : null,
-    );
+
+    Map<String, dynamic>? profileUpdate;
+
+    if (prevTargetLang != _pangeaController.languageController.userL2) {
+      profileUpdate ??= {};
+      profileUpdate['prev_target_lang'] = prevTargetLang;
+    }
+
+    if (prevBaseLang != _pangeaController.languageController.userL1) {
+      profileUpdate ??= {};
+      profileUpdate['prev_base_lang'] = prevBaseLang;
+    }
+
+    setState(profileUpdate);
   }
 
   /// A completer for the profile model of a user.