From 2e697714635b49f2d9e11913715bad8086a59fa2 Mon Sep 17 00:00:00 2001
From: Timo Notheisen <timo.notheisen@js-soft.com>
Date: Tue, 28 Jan 2025 13:26:50 +0100
Subject: [PATCH] refactor: filter for distinct handles in PushService instead
 of in the repository

---
 .../Persistence/Repository/IPnsRegistrationsRepository.cs   | 2 +-
 .../Persistence/Repository/PnsRegistrationsRepository.cs    | 6 ++----
 .../Devices.Infrastructure/PushNotifications/PushService.cs | 6 ++++--
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/Modules/Devices/src/Devices.Application/Infrastructure/Persistence/Repository/IPnsRegistrationsRepository.cs b/Modules/Devices/src/Devices.Application/Infrastructure/Persistence/Repository/IPnsRegistrationsRepository.cs
index 0ab61578a2..6c3a99fe99 100644
--- a/Modules/Devices/src/Devices.Application/Infrastructure/Persistence/Repository/IPnsRegistrationsRepository.cs
+++ b/Modules/Devices/src/Devices.Application/Infrastructure/Persistence/Repository/IPnsRegistrationsRepository.cs
@@ -9,7 +9,7 @@ public interface IPnsRegistrationsRepository
     Task Add(PnsRegistration registration, CancellationToken cancellationToken);
     Task Update(PnsRegistration registration, CancellationToken cancellationToken);
     Task<PnsRegistration?> FindByDeviceId(DeviceId deviceId, CancellationToken cancellationToken, bool track = false);
-    Task<List<PnsRegistration>> FindDistinctByDeviceIds(DeviceId[] deviceIds, CancellationToken cancellationToken, bool track = false);
+    Task<PnsRegistration[]> FindByDeviceIds(DeviceId[] deviceIds, CancellationToken cancellationToken, bool track = false);
     Task<int> Delete(List<DeviceId> deviceIds, CancellationToken cancellationToken);
     Task Delete(Expression<Func<PnsRegistration, bool>> filter, CancellationToken cancellationToken);
 }
diff --git a/Modules/Devices/src/Devices.Infrastructure/Persistence/Repository/PnsRegistrationsRepository.cs b/Modules/Devices/src/Devices.Infrastructure/Persistence/Repository/PnsRegistrationsRepository.cs
index 644129ce8e..55cfc539ea 100644
--- a/Modules/Devices/src/Devices.Infrastructure/Persistence/Repository/PnsRegistrationsRepository.cs
+++ b/Modules/Devices/src/Devices.Infrastructure/Persistence/Repository/PnsRegistrationsRepository.cs
@@ -42,13 +42,11 @@ public async Task Add(PnsRegistration registration, CancellationToken cancellati
             .FirstOrDefaultAsync(registration => registration.DeviceId == deviceId, cancellationToken);
     }
 
-    public async Task<List<PnsRegistration>> FindDistinctByDeviceIds(DeviceId[] deviceIds, CancellationToken cancellationToken, bool track = false)
+    public async Task<PnsRegistration[]> FindByDeviceIds(DeviceId[] deviceIds, CancellationToken cancellationToken, bool track = false)
     {
         return await (track ? _registrations : _readonlyRegistrations)
             .Where(r => deviceIds.Contains(r.DeviceId))
-            .GroupBy(r => r.Handle)
-            .Select(g => g.First())
-            .ToListAsync(cancellationToken);
+            .ToArrayAsync(cancellationToken);
     }
 
     public async Task<int> Delete(List<DeviceId> deviceIds, CancellationToken cancellationToken)
diff --git a/Modules/Devices/src/Devices.Infrastructure/PushNotifications/PushService.cs b/Modules/Devices/src/Devices.Infrastructure/PushNotifications/PushService.cs
index 563f80c875..b0e6ed0878 100644
--- a/Modules/Devices/src/Devices.Infrastructure/PushNotifications/PushService.cs
+++ b/Modules/Devices/src/Devices.Infrastructure/PushNotifications/PushService.cs
@@ -69,9 +69,11 @@ private async Task SendNotificationInternal(IPushNotification notification, Devi
     {
         var deviceIds = devices.Select(d => d.Id).ToArray();
 
-        var registrations = await _pnsRegistrationsRepository.FindDistinctByDeviceIds(deviceIds, cancellationToken);
+        var registrations = await _pnsRegistrationsRepository.FindByDeviceIds(deviceIds, cancellationToken);
 
-        var groups = registrations.GroupBy(registration => registration.Handle.Platform);
+        var groups = registrations
+            .DistinctBy(r => r.Handle) // Since there can be multiple registrations with the same handle, we should make sure we send the same push notification only once per handle
+            .GroupBy(r => r.Handle.Platform);
 
         foreach (var group in groups)
         {