[mob][photos] Add guards to make sure no email is linked to more than one person

mobile/lib/ui/viewer/people/link_email_screen.dart

@@ -24,6 +24,7 @@ import 'package:photos/ui/components/models/button_type.dart';
 import "package:photos/ui/components/text_input_widget.dart";
 import 'package:photos/ui/sharing/user_avator_widget.dart';
 import "package:photos/utils/dialog_util.dart";
+import "package:photos/utils/person_contact_linking_util.dart";
 import "package:photos/utils/share_util.dart";
 
 class LinkEmailScreen extends StatefulWidget {
@@ -214,17 +215,21 @@ class _LinkEmailScreen extends State<LinkEmailScreen> {
                           }
                         });
                       } else {
-                        final result = await linkEmailToPerson(
-                          newEmail,
-                          widget.personID!,
-                          context,
-                        );
-                        if (!result) {
-                          _textController.clear();
-                          return;
-                        }
+                        try {
+                          final result = await linkEmailToPerson(
+                            newEmail,
+                            widget.personID!,
+                            context,
+                          );
+                          if (!result) {
+                            _textController.clear();
+                            return;
+                          }
 
-                        Navigator.of(context).pop(newEmail);
+                          Navigator.of(context).pop(newEmail);
+                        } catch (e) {
+                          _logger.severe("Failed to link email to person", e);
+                        }
                       }
                     },
                   ),
@@ -325,6 +330,10 @@ class _LinkEmailScreen extends State<LinkEmailScreen> {
     String personID,
     BuildContext context,
   ) async {
+    if (await checkIfEmailAlreadyAssignedToAPerson(context, email)) {
+      throw Exception("Email already linked to a person");
+    }
+
     String? publicKey;
 
     try {

mobile/lib/ui/viewer/people/person_selection_action_widgets.dart

@@ -17,6 +17,7 @@ import "package:photos/ui/components/dialog_widget.dart";
 import "package:photos/ui/components/models/button_type.dart";
 import "package:photos/ui/viewer/search/result/person_face_widget.dart";
 import "package:photos/utils/dialog_util.dart";
+import "package:photos/utils/person_contact_linking_util.dart";
 import "package:photos/utils/toast_util.dart";
 
 class PersonEntityWithThumbnailFile {
@@ -45,6 +46,7 @@ class _LinkContactToPersonSelectionPageState
     extends State<LinkContactToPersonSelectionPage> {
   late Future<List<PersonEntityWithThumbnailFile>>
       _personEntitiesWithThumnailFile;
+  final _logger = Logger('LinkContactToPersonSelectionPage');
 
   @override
   void initState() {
@@ -115,15 +117,21 @@ class _LinkContactToPersonSelectionPageState
               itemBuilder: (context, index) {
                 return _RoundedPersonFaceWidget(
                   onTap: () async {
-                    await linkPersonToContact(
-                      context,
-                      emailToLink: widget.emailToLink!,
-                      personEntity: results[index].person,
-                    ).then((updatedPerson) {
-                      if (updatedPerson != null) {
-                        Navigator.of(context).pop(updatedPerson);
-                      }
-                    });
+                    try {
+                      unawaited(
+                        linkPersonToContact(
+                          context,
+                          emailToLink: widget.emailToLink!,
+                          personEntity: results[index].person,
+                        ).then((updatedPerson) {
+                          if (updatedPerson != null) {
+                            Navigator.of(context).pop(updatedPerson);
+                          }
+                        }),
+                      );
+                    } catch (e) {
+                      _logger.severe("Failed to link person to contact", e);
+                    }
                   },
                   itemSize: itemSize,
                   personEntitiesWithThumbnailFile: results[index],
@@ -141,6 +149,10 @@ class _LinkContactToPersonSelectionPageState
     required String emailToLink,
     required PersonEntity personEntity,
   }) async {
+    if (await checkIfEmailAlreadyAssignedToAPerson(context, emailToLink)) {
+      throw Exception("Email already linked");
+    }
+
     final personName = personEntity.data.name;
     PersonEntity? updatedPerson;
     final result = await showDialogWidget(

mobile/lib/ui/viewer/people/save_or_edit_person.dart

@@ -31,6 +31,7 @@ import "package:photos/ui/viewer/people/person_row_item.dart";
 import "package:photos/ui/viewer/search/result/person_face_widget.dart";
 import "package:photos/utils/dialog_util.dart";
 import "package:photos/utils/navigation_util.dart";
+import "package:photos/utils/person_contact_linking_util.dart";
 import "package:photos/utils/toast_util.dart";
 
 class SaveOrEditPerson extends StatefulWidget {
@@ -379,15 +380,23 @@ class _SaveOrEditPersonState extends State<SaveOrEditPerson> {
           shouldStickToDarkTheme: true,
           onTap: () async {
             if (widget.isEditing) {
-              updatedPersonEntity = await updatePerson(context);
+              try {
+                updatedPersonEntity = await updatePerson(context);
+              } catch (e) {
+                _logger.severe("Error updating person", e);
+              }
             } else {
-              updatedPersonEntity = await addNewPerson(
-                context,
-                text: _inputName,
-                clusterID: widget.clusterID!,
-                birthdate: _selectedDate,
-                email: _email,
-              );
+              try {
+                updatedPersonEntity = await addNewPerson(
+                  context,
+                  text: _inputName,
+                  clusterID: widget.clusterID!,
+                  birthdate: _selectedDate,
+                  email: _email,
+                );
+              } catch (e) {
+                _logger.severe("Error updating person", e);
+              }
             }
           },
         ),
@@ -530,6 +539,11 @@ class _SaveOrEditPersonState extends State<SaveOrEditPerson> {
     String? birthdate,
     String? email,
   }) async {
+    if (email != null &&
+        email.isNotEmpty &&
+        await checkIfEmailAlreadyAssignedToAPerson(context, email)) {
+      throw Exception("Email already assigned to a person");
+    }
     try {
       if (userAlreadyAssigned) {
         return null;
@@ -576,6 +590,12 @@ class _SaveOrEditPersonState extends State<SaveOrEditPerson> {
 
   Future<PersonEntity?> updatePerson(BuildContext context) async {
     try {
+      if (_email != null &&
+          _email!.isNotEmpty &&
+          _email != person!.data.email &&
+          await checkIfEmailAlreadyAssignedToAPerson(context, _email!)) {
+        throw Exception("Email already assigned to a person");
+      }
       final String name = _inputName.trim();
       final String? birthDate = _selectedDate;
       final personEntity = await PersonService.instance.updateAttributes(

mobile/lib/utils/person_contact_linking_util.dart

@@ -0,0 +1,25 @@
+import "dart:io";
+
+import "package:flutter/material.dart";
+import "package:photos/services/machine_learning/face_ml/person/person_service.dart";
+import "package:photos/utils/dialog_util.dart";
+
+Future<bool> checkIfEmailAlreadyAssignedToAPerson(
+  BuildContext context,
+  String email,
+) async {
+  final persons = await PersonService.instance.getPersons();
+  for (var person in persons) {
+    if (person.data.email == email) {
+      await showErrorDialog(
+        context,
+        "Email already linked",
+        "This email is already linked to a person",
+        useRootNavigator: Platform.isIOS,
+      );
+
+      return true;
+    }
+  }
+  return false;
+}