feat: app error handling

app/lib/l10n/app_en.arb

@@ -213,5 +213,12 @@
       }
   },
   "app_outdated_message": "A new version of the StudyU App is available. Please update to get the latest features and improvements. Thank you for your support!",
-  "update_now": "Update now"
+  "update_now": "Update now",
+
+  "error_missing_study": "Could not login and retrieve the study subject. \nOne reason for this might be that the study subject is no longer available and only resides in app backup",
+  "join_new_study": "Join a new study",
+  "join_new_study_description": "Join a new study to continue using the app. Your previous study data will be deleted.",
+  "retry": "Retry",
+  "retry_description": "Try again",
+    "error_no_internet": "No internet connection"
 }

app/lib/models/app_error.dart

@@ -0,0 +1,28 @@
+enum AppErrorTypes {
+  retrieveSubject,
+  storeSubject,
+  network,
+  notification,
+  unknown,
+}
+
+class ErrorAction {
+  final String actionText;
+  final String? actionDescription;
+  final Future<void> Function() callback;
+
+  ErrorAction(this.actionText, this.callback, {this.actionDescription});
+}
+
+class AppError {
+  final AppErrorTypes type;
+  final String message;
+  final List<ErrorAction>? actions;
+
+  AppError(this.type, this.message, {this.actions});
+
+  @override
+  String toString() {
+    return '$message, type: $type';
+  }
+}

app/lib/screens/app_onboarding/loading_screen.dart

@@ -3,13 +3,15 @@ import 'dart:io';
 import 'package:flutter/material.dart';
 import 'package:flutter_gen/gen_l10n/app_localizations.dart';
 import 'package:provider/provider.dart';
+import 'package:studyu_app/models/app_error.dart';
 import 'package:studyu_app/models/app_state.dart';
 import 'package:studyu_app/routes.dart';
 import 'package:studyu_app/screens/app_onboarding/iframe_helper.dart';
 import 'package:studyu_app/screens/app_onboarding/preview.dart';
 import 'package:studyu_app/screens/study/onboarding/eligibility_screen.dart';
 import 'package:studyu_app/screens/study/tasks/task_screen.dart';
 import 'package:studyu_app/util/cache.dart';
+import 'package:studyu_app/util/error_handler.dart';
 import 'package:studyu_app/util/schedule_notifications.dart';
 import 'package:studyu_core/core.dart';
 import 'package:studyu_flutter_common/studyu_flutter_common.dart';
@@ -43,7 +45,20 @@ class _LoadingScreenState extends State<LoadingScreen> {
       await noSubjectFound();
       return;
     }
-    StudySubject? subject = await _retrieveSubject(selectedSubjectId);
+
+    StudySubject? subject;
+
+    try {
+      subject = await _retrieveSubject(selectedSubjectId);
+    } catch (error) {
+      if (error is AppError && error.type == AppErrorTypes.retrieveSubject) {
+        if (!mounted) return;
+        await ErrorHandler.handleError(context, error);
+
+        return;
+      }
+    }
+
     if (!mounted) return;
     if (subject != null) {
       subject = await Cache.synchronize(subject);
@@ -89,6 +104,7 @@ class _LoadingScreenState extends State<LoadingScreen> {
         debugPrint(
           "Could not login and retrieve the study subject: $exception",
         );
+
         if (exception is SocketException) {
           subject = await Cache.loadSubject();
           StudyULogger.info("Offline mode with cached subject: $subject");
@@ -101,10 +117,34 @@ class _LoadingScreenState extends State<LoadingScreen> {
           // 4. Open the app but do not join a study
           // 5. Restart the app. Either only this error shows up, worst case is
           // app hangs and is unresponsive
-          StudyULogger.fatal('Could not login and retrieve the study subject. '
-              'One reason for this might be that the study subject is no '
-              'longer available and only resides in app backup');
-          throw Exception("Remote subject not found");
+
+          throw AppError(
+            AppErrorTypes.retrieveSubject,
+            AppLocalizations.of(context)!.error_missing_study,
+            actions: [
+              ErrorAction(
+                AppLocalizations.of(context)!.join_new_study,
+                () async {
+                  await cancelNotifications(context);
+                  await deleteActiveStudyReference();
+                  if (!mounted) return;
+                  Navigator.pushReplacementNamed(context, Routes.welcome);
+                },
+                actionDescription:
+                    AppLocalizations.of(context)!.join_new_study_description,
+              ),
+              ErrorAction(
+                AppLocalizations.of(context)!.retry,
+                () async {
+                  Navigator.of(context).pop();
+
+                  await initStudy();
+                },
+                actionDescription:
+                    AppLocalizations.of(context)!.retry_description,
+              ),
+            ],
+          );
         }
       }
     }

app/lib/screens/app_onboarding/preview.dart

@@ -117,6 +117,17 @@ class Preview {
     return queryParameters!.containsKey(key) && queryParameters![key] == value;
   }
 
+  Future<StudySubject?> _fetchRemoteSubject(String selectedStudyObjectId) {
+    return SupabaseQuery.getById<StudySubject>(
+      selectedStudyObjectId,
+      selectedColumns: [
+        '*',
+        'study!study_subject_studyId_fkey(*)',
+        'subject_progress(*)',
+      ],
+    );
+  }
+
   /// createSubject: If true, the method will return a new StudySubject if none can be found. Otherwise, null is returned
   Future<StudySubject?> getStudySubject(
     AppState state, {
@@ -158,23 +169,27 @@ class Preview {
           // User is already subscribed to a study
           return subject;
         }
-        subject = await SupabaseQuery.getById<StudySubject>(
-          selectedStudyObjectId!,
-          selectedColumns: [
-            '*',
-            'study!study_subject_studyId_fkey(*)',
-            'subject_progress(*)',
-          ],
-        );
-        if (subject != null && subject!.studyId == study!.id) {
+        subject = await _fetchRemoteSubject(selectedStudyObjectId!);
+
+        if (subject != null && subject!.studyId == study!.id) return subject;
+      } catch (e) {
+        try {
+          StudyULogger.info(
+              '[PreviewApp]: Failed fetching subject: $e. Trying to sign in participant');
+
+          if (await signInParticipant()) {
+            subject = await _fetchRemoteSubject(selectedStudyObjectId!);
+          }
+
           // User is already subscribed to the study
-          return subject;
+          if (subject != null && subject!.studyId == study!.id) return subject;
+        } catch (e) {
+          StudyULogger.error(
+              '[PreviewApp]: Failed fetching subject after sign in: $e');
         }
-      } catch (e) {
-        print('[PreviewApp]: Failed fetching subject: $e');
-        // todo try sign in again if token expired see loading screen
       }
     }
+
     if (createSubject) {
       // Create a new study subject
       subject = await _createFakeSubject(state);
@@ -209,9 +224,10 @@ class Preview {
         await storeActiveSubjectId(subject!.id);
         // print("[PreviewApp]: Saved subject");
       } catch (e) {
-        print('[PreviewApp]: Failed creating subject: $e');
+        StudyULogger.error('[PreviewApp]: Failed creating subject: $e');
       }
     }
+
     return subject;
   }
 

app/lib/screens/study/dashboard/settings.dart

@@ -7,11 +7,14 @@ import 'package:provider/provider.dart';
 import 'package:studyu_app/models/app_state.dart';
 import 'package:studyu_app/routes.dart';
 import 'package:studyu_app/util/app_analytics.dart';
+import 'package:studyu_app/util/error_handler.dart';
 import 'package:studyu_app/util/localization.dart';
 import 'package:studyu_app/util/schedule_notifications.dart';
 import 'package:studyu_core/core.dart';
 import 'package:studyu_flutter_common/studyu_flutter_common.dart';
 
+import '../../../models/app_error.dart';
+
 class Settings extends StatefulWidget {
   const Settings({super.key});
 
@@ -186,14 +189,26 @@ class OptOutAlertDialog extends StatelessWidget {
           label: Text(AppLocalizations.of(context)!.opt_out),
           style: ElevatedButton.styleFrom(backgroundColor: Colors.orange[800]),
           onPressed: () async {
-            await subject!.softDelete();
-            await deleteActiveStudyReference();
-            if (context.mounted) await cancelNotifications(context);
-            if (context.mounted) {
-              Navigator.pushNamedAndRemoveUntil(
+            try {
+              await subject!.softDelete();
+              await deleteActiveStudyReference();
+              if (context.mounted) await cancelNotifications(context);
+              if (context.mounted) {
+                Navigator.pushNamedAndRemoveUntil(
+                  context,
+                  Routes.studySelection,
+                  (_) => false,
+                );
+              }
+            } on SocketException catch (_) {
+              ErrorHandler.showSnackbar(context, "Connection error");
+            } on AppError catch (e) {
+              ErrorHandler.showSnackbar(context, e.message);
+            } catch (e) {
+              StudyULogger.error(e.toString());
+              ErrorHandler.showSnackbar(
                 context,
-                Routes.studySelection,
-                (_) => false,
+                "An error occured while opting out. Please try again later",
               );
             }
           },
@@ -231,7 +246,18 @@ class DeleteAlertDialog extends StatelessWidget {
                     (_) => false,
                   );
                 }
-              } on SocketException catch (_) {}
+              } on SocketException catch (_) {
+                ErrorHandler.showSnackbar(context, "Connection error");
+              } on AppError catch (e) {
+                ErrorHandler.showSnackbar(context, e.message);
+              } catch (e) {
+                StudyULogger.error(e.toString());
+
+                ErrorHandler.showSnackbar(
+                  context,
+                  "An error occured while deleting data. Please try again later",
+                );
+              }
             },
           ),
         ],

app/lib/screens/study/onboarding/kickoff.dart

@@ -1,10 +1,14 @@
+import 'dart:io';
+
 import 'package:flutter/material.dart';
 import 'package:flutter_gen/gen_l10n/app_localizations.dart';
 import 'package:material_design_icons_flutter/material_design_icons_flutter.dart';
 import 'package:provider/provider.dart';
+import 'package:studyu_app/models/app_error.dart';
 import 'package:studyu_app/models/app_state.dart';
 import 'package:studyu_app/routes.dart';
 import 'package:studyu_app/util/cache.dart';
+import 'package:studyu_app/util/error_handler.dart';
 import 'package:studyu_core/core.dart';
 import 'package:studyu_flutter_common/studyu_flutter_common.dart';
 
@@ -37,7 +41,34 @@ class _KickoffScreen extends State<KickoffScreen> {
         Routes.dashboard,
         (_) => false,
       );
+    } on SocketException catch (e) {
+      ErrorHandler.showSnackbar(
+        context,
+        AppLocalizations.of(context)!.error_no_internet,
+      );
+
+      StudyULogger.fatal('Failed creating subject: $e');
     } catch (e) {
+      ErrorHandler.handleError(
+          context,
+          AppError(AppErrorTypes.storeSubject,
+              'An error occurred while preparing the study for you.',
+              actions: [
+                ErrorAction(AppLocalizations.of(context)!.retry,
+                    () => _storeUserStudy(context),
+                    actionDescription:
+                        AppLocalizations.of(context)!.retry_description),
+                ErrorAction(
+                  AppLocalizations.of(context)!.join_new_study,
+                  () => Navigator.pushNamedAndRemoveUntil(
+                    context,
+                    Routes.studySelection,
+                    (_) => false,
+                  ),
+                  actionDescription:
+                      AppLocalizations.of(context)!.join_new_study_description,
+                ),
+              ]));
       StudyULogger.fatal('Failed creating subject: $e');
     }
   }

app/lib/screens/study/onboarding/study_selection.dart

@@ -249,7 +249,7 @@ class _InviteCodeDialogState extends State<InviteCodeDialog> {
                     .select()
                     .single();
               } on PostgrestException catch (error) {
-                print(error.message);
+                StudyULogger.error(error.message);
                 setState(() {
                   _errorMessage = error.message;
                 });
@@ -272,7 +272,7 @@ class _InviteCodeDialogState extends State<InviteCodeDialog> {
                     params: {'invite_code': _controller.text},
                   ).single();
                 } on PostgrestException catch (error) {
-                  print(error.message);
+                  StudyULogger.error(error.message);
                   setState(() {
                     _errorMessage = error.message;
                   });

app/lib/screens/study/tasks/task_screen.dart

@@ -3,10 +3,12 @@ import 'dart:io';
 import 'package:flutter/material.dart';
 import 'package:flutter_gen/gen_l10n/app_localizations.dart';
 import 'package:provider/provider.dart';
+import 'package:studyu_app/models/app_error.dart';
 import 'package:studyu_app/models/app_state.dart';
 import 'package:studyu_app/screens/study/tasks/intervention/checkmark_task_widget.dart';
 import 'package:studyu_app/screens/study/tasks/observation/questionnaire_task_widget.dart';
 import 'package:studyu_app/util/cache.dart';
+import 'package:studyu_app/util/error_handler.dart';
 import 'package:studyu_app/widgets/html_text.dart';
 import 'package:studyu_core/core.dart';
 
@@ -95,9 +97,20 @@ Future<void> handleTaskCompletion(
   } on SocketException {
     await Cache.storeSubject(activeSubject);
   } catch (exception) {
-    debugPrint("Could not save results");
+    StudyULogger.error(exception);
     if (!context.mounted) return;
-    ScaffoldMessenger.of(context).showSnackBar(
+    ErrorHandler.handleError(
+      context,
+      AppError(
+        AppErrorTypes.unknown,
+        AppLocalizations.of(context)!.could_not_save_results,
+        actions: [
+          ErrorAction(AppLocalizations.of(context)!.retry,
+              () => handleTaskCompletion(context, completionCallback)),
+        ],
+      ),
+    );
+    /*ScaffoldMessenger.of(context).showSnackBar(
       SnackBar(
         content: Text(AppLocalizations.of(context)!.could_not_save_results),
         duration: const Duration(seconds: 10),
@@ -106,7 +119,7 @@ Future<void> handleTaskCompletion(
           onPressed: () => handleTaskCompletion(context, completionCallback),
         ),
       ),
-    );
+    );*/
     rethrow;
   }
 }