[PM-19659] Clean up Notifications code (#6244)

* Move PushType to Platform Folder

- Move the PushType next to the rest of push notification code
- Specifically exclude it from needing Platform code review
- Add tests establishing rules Platform has for usage of this enum, making it safe to have no owner

* Move NotificationHub code into Platform/Push directory

* Update NotificationHub namespace imports

* Add attribute for storing push type metadata

* Rename Push Engines to have PushEngine suffix

* Move Push Registration items to their own directory

* Push code move

* Add expected usage comment

* Add Push feature registration method

- Make method able to be called multipes times with no ill effects

* Add Push Registration service entrypoint and tests

* Use new service entrypoints

* Test changes

.github/CODEOWNERS

@@ -92,6 +92,8 @@ src/Admin/Views/Tools @bitwarden/team-billing-dev
 **/.dockerignore @bitwarden/team-platform-dev
 **/Dockerfile @bitwarden/team-platform-dev
 **/entrypoint.sh @bitwarden/team-platform-dev
+# The PushType enum is expected to be editted by anyone without need for Platform review
+src/Core/Platform/Push/PushType.cs
 
 # Multiple owners - DO NOT REMOVE (BRE)
 **/packages.lock.json

src/Api/Models/Request/DeviceRequestModels.cs

@@ -4,7 +4,7 @@
 using System.ComponentModel.DataAnnotations;
 using Bit.Core.Entities;
 using Bit.Core.Enums;
-using Bit.Core.NotificationHub;
+using Bit.Core.Platform.PushRegistration;
 using Bit.Core.Utilities;
 
 namespace Bit.Api.Models.Request;

src/Api/Platform/Push/Controllers/PushController.cs

@@ -6,9 +6,9 @@ using System.Text.Json;
 using Bit.Core.Context;
 using Bit.Core.Exceptions;
 using Bit.Core.Models.Api;
-using Bit.Core.NotificationHub;
 using Bit.Core.Platform.Push;
 using Bit.Core.Platform.Push.Internal;
+using Bit.Core.Platform.PushRegistration;
 using Bit.Core.Settings;
 using Bit.Core.Utilities;
 using Microsoft.AspNetCore.Authorization;

src/Core/Enums/PushType.cs

@@ -1,35 +0,0 @@
-namespace Bit.Core.Enums;
-
-public enum PushType : byte
-{
-    SyncCipherUpdate = 0,
-    SyncCipherCreate = 1,
-    SyncLoginDelete = 2,
-    SyncFolderDelete = 3,
-    SyncCiphers = 4,
-
-    SyncVault = 5,
-    SyncOrgKeys = 6,
-    SyncFolderCreate = 7,
-    SyncFolderUpdate = 8,
-    SyncCipherDelete = 9,
-    SyncSettings = 10,
-
-    LogOut = 11,
-
-    SyncSendCreate = 12,
-    SyncSendUpdate = 13,
-    SyncSendDelete = 14,
-
-    AuthRequest = 15,
-    AuthRequestResponse = 16,
-
-    SyncOrganizations = 17,
-    SyncOrganizationStatusChanged = 18,
-    SyncOrganizationCollectionSettingChanged = 19,
-
-    Notification = 20,
-    NotificationStatus = 21,
-
-    RefreshSecurityTasks = 22
-}

src/Core/Models/PushNotification.cs

@@ -1,9 +1,11 @@
-#nullable enable
+using Bit.Core.Enums;
-using Bit.Core.Enums;
 using Bit.Core.NotificationCenter.Enums;
 
 namespace Bit.Core.Models;
 
+// New push notification payload models should not be defined in this file
+// they should instead be defined in file owned by your team.
+
 public class PushNotificationData<T>
 {
     public PushNotificationData(PushType type, T payload, string? contextId)

src/Core/Platform/Push/Engines/AzureQueuePushEngine.cs

@@ -1,5 +1,4 @@
-#nullable enable
+using System.Text.Json;
-using System.Text.Json;
 using Azure.Storage.Queues;
 using Bit.Core.Context;
 using Bit.Core.Enums;
@@ -13,17 +12,16 @@ using Microsoft.Extensions.Logging;
 
 namespace Bit.Core.Platform.Push.Internal;
 
-public class AzureQueuePushNotificationService : IPushEngine
+public class AzureQueuePushEngine : IPushEngine
 {
     private readonly QueueClient _queueClient;
     private readonly IHttpContextAccessor _httpContextAccessor;
 
-    public AzureQueuePushNotificationService(
+    public AzureQueuePushEngine(
         [FromKeyedServices("notifications")] QueueClient queueClient,
         IHttpContextAccessor httpContextAccessor,
         IGlobalSettings globalSettings,
-        ILogger<AzureQueuePushNotificationService> logger,
+        ILogger<AzureQueuePushEngine> logger)
-        TimeProvider timeProvider)
     {
         _queueClient = queueClient;
         _httpContextAccessor = httpContextAccessor;

src/Core/Platform/Push/Engines/MultiServicePushNotificationService.cs

@@ -1,5 +1,4 @@
-#nullable enable
+using Bit.Core.Enums;
-using Bit.Core.Enums;
 using Bit.Core.Settings;
 using Bit.Core.Vault.Entities;
 using Microsoft.Extensions.Logging;
@@ -8,7 +7,7 @@ namespace Bit.Core.Platform.Push.Internal;
 
 public class MultiServicePushNotificationService : IPushNotificationService
 {
-    private readonly IEnumerable<IPushEngine> _services;
+    private readonly IPushEngine[] _services;
 
     public Guid InstallationId { get; }
 
@@ -22,7 +21,8 @@ public class MultiServicePushNotificationService : IPushNotificationService
         GlobalSettings globalSettings,
         TimeProvider timeProvider)
     {
-        _services = services;
+        // Filter out any NoopPushEngine's
+        _services = [.. services.Where(engine => engine is not NoopPushEngine)];
 
         Logger = logger;
         Logger.LogInformation("Hub services: {Services}", _services.Count());

src/Core/Platform/Push/Engines/NoopPushEngine.cs

@@ -1,10 +1,9 @@
-#nullable enable
+using Bit.Core.Enums;
-using Bit.Core.Enums;
 using Bit.Core.Vault.Entities;
 
 namespace Bit.Core.Platform.Push.Internal;
 
-internal class NoopPushNotificationService : IPushEngine
+internal class NoopPushEngine : IPushEngine
 {
     public Task PushCipherAsync(Cipher cipher, PushType pushType, IEnumerable<Guid>? collectionIds) => Task.CompletedTask;
 

src/Core/Platform/Push/Engines/NotificationsApiPushEngine.cs

@@ -1,5 +1,4 @@
-#nullable enable
+using Bit.Core.Context;
-using Bit.Core.Context;
 using Bit.Core.Enums;
 using Bit.Core.Models;
 using Bit.Core.Services;
@@ -8,23 +7,22 @@ using Bit.Core.Vault.Entities;
 using Microsoft.AspNetCore.Http;
 using Microsoft.Extensions.Logging;
 
-// This service is not in the `Internal` namespace because it has direct external references.
+namespace Bit.Core.Platform.Push.Internal;
-namespace Bit.Core.Platform.Push;
 
 /// <summary>
 /// Sends non-mobile push notifications to the Azure Queue Api, later received by Notifications Api.
 /// Used by Cloud-Hosted environments.
 /// Received by AzureQueueHostedService message receiver in Notifications project.
 /// </summary>
-public class NotificationsApiPushNotificationService : BaseIdentityClientService, IPushEngine
+public class NotificationsApiPushEngine : BaseIdentityClientService, IPushEngine
 {
     private readonly IHttpContextAccessor _httpContextAccessor;
 
-    public NotificationsApiPushNotificationService(
+    public NotificationsApiPushEngine(
         IHttpClientFactory httpFactory,
         GlobalSettings globalSettings,
         IHttpContextAccessor httpContextAccessor,
-        ILogger<NotificationsApiPushNotificationService> logger)
+        ILogger<NotificationsApiPushEngine> logger)
         : base(
             httpFactory,
             globalSettings.BaseServiceUri.InternalNotifications,

src/Core/Platform/Push/Engines/RelayPushEngine.cs

@@ -1,5 +1,4 @@
-#nullable enable
+using Bit.Core.Context;
-using Bit.Core.Context;
 using Bit.Core.Enums;
 using Bit.Core.IdentityServer;
 using Bit.Core.Models;
@@ -19,18 +18,18 @@ namespace Bit.Core.Platform.Push.Internal;
 /// Used by Self-Hosted environments.
 /// Received by PushController endpoint in Api project.
 /// </summary>
-public class RelayPushNotificationService : BaseIdentityClientService, IPushEngine
+public class RelayPushEngine : BaseIdentityClientService, IPushEngine
 {
     private readonly IDeviceRepository _deviceRepository;
     private readonly IHttpContextAccessor _httpContextAccessor;
 
 
-    public RelayPushNotificationService(
+    public RelayPushEngine(
         IHttpClientFactory httpFactory,
         IDeviceRepository deviceRepository,
         GlobalSettings globalSettings,
         IHttpContextAccessor httpContextAccessor,
-        ILogger<RelayPushNotificationService> logger)
+        ILogger<RelayPushEngine> logger)
         : base(
             httpFactory,
             globalSettings.PushRelayBaseUri,

src/Core/Platform/Push/IPushEngine.cs

@@ -1,8 +1,7 @@
-#nullable enable
+using Bit.Core.Enums;
-using Bit.Core.Enums;
 using Bit.Core.Vault.Entities;
 
-namespace Bit.Core.Platform.Push;
+namespace Bit.Core.Platform.Push.Internal;
 
 public interface IPushEngine
 {

src/Core/Platform/Push/IPushNotificationService.cs

@@ -1,5 +1,4 @@
-#nullable enable
+using Bit.Core.AdminConsole.Entities;
-using Bit.Core.AdminConsole.Entities;
 using Bit.Core.Auth.Entities;
 using Bit.Core.Enums;
 using Bit.Core.Models;
@@ -10,10 +9,27 @@ using Microsoft.Extensions.Logging;
 
 namespace Bit.Core.Platform.Push;
 
+/// <summary>
+/// Used to Push notifications to end-user devices.
+/// </summary>
+/// <remarks>
+/// New notifications should not be wired up inside this service. You may either directly call the
+/// <see cref="PushAsync"/> method in your service to send your notification or if you want your notification
+/// sent by other teams you can make an extension method on this service with a well typed definition
+/// of your notification. You may also make your own service that injects this and exposes methods for each of
+/// your notifications.
+/// </remarks>
 public interface IPushNotificationService
 {
+    private const string ServiceDeprecation = "Do not use the services exposed here, instead use your own services injected in your service.";
+
+    [Obsolete(ServiceDeprecation, DiagnosticId = "BWP0001")]
     Guid InstallationId { get; }
+
+    [Obsolete(ServiceDeprecation, DiagnosticId = "BWP0001")]
     TimeProvider TimeProvider { get; }
+
+    [Obsolete(ServiceDeprecation, DiagnosticId = "BWP0001")]
     ILogger Logger { get; }
 
     #region Legacy method, to be removed soon.
@@ -80,7 +96,9 @@ public interface IPushNotificationService
             Payload = new UserPushNotification
             {
                 UserId = userId,
+#pragma warning disable BWP0001 // Type or member is obsolete
                 Date = TimeProvider.GetUtcNow().UtcDateTime,
+#pragma warning restore BWP0001 // Type or member is obsolete
             },
             ExcludeCurrentContext = false,
         });
@@ -94,7 +112,9 @@ public interface IPushNotificationService
             Payload = new UserPushNotification
             {
                 UserId = userId,
+#pragma warning disable BWP0001 // Type or member is obsolete
                 Date = TimeProvider.GetUtcNow().UtcDateTime,
+#pragma warning restore BWP0001 // Type or member is obsolete
             },
             ExcludeCurrentContext = false,
         });
@@ -108,7 +128,9 @@ public interface IPushNotificationService
             Payload = new UserPushNotification
             {
                 UserId = userId,
+#pragma warning disable BWP0001 // Type or member is obsolete
                 Date = TimeProvider.GetUtcNow().UtcDateTime,
+#pragma warning restore BWP0001 // Type or member is obsolete
             },
             ExcludeCurrentContext = false,
         });
@@ -122,7 +144,9 @@ public interface IPushNotificationService
             Payload = new UserPushNotification
             {
                 UserId = userId,
+#pragma warning disable BWP0001 // Type or member is obsolete
                 Date = TimeProvider.GetUtcNow().UtcDateTime,
+#pragma warning restore BWP0001 // Type or member is obsolete
             },
             ExcludeCurrentContext = false,
         });
@@ -136,7 +160,9 @@ public interface IPushNotificationService
             Payload = new UserPushNotification
             {
                 UserId = userId,
+#pragma warning disable BWP0001 // Type or member is obsolete
                 Date = TimeProvider.GetUtcNow().UtcDateTime,
+#pragma warning restore BWP0001 // Type or member is obsolete
             },
             ExcludeCurrentContext = false,
         });
@@ -150,7 +176,9 @@ public interface IPushNotificationService
             Payload = new UserPushNotification
             {
                 UserId = userId,
+#pragma warning disable BWP0001 // Type or member is obsolete
                 Date = TimeProvider.GetUtcNow().UtcDateTime,
+#pragma warning restore BWP0001 // Type or member is obsolete
             },
             ExcludeCurrentContext = excludeCurrentContextFromPush,
         });
@@ -231,7 +259,9 @@ public interface IPushNotificationService
             ClientType = notification.ClientType,
             UserId = notification.UserId,
             OrganizationId = notification.OrganizationId,
+#pragma warning disable BWP0001 // Type or member is obsolete
             InstallationId = notification.Global ? InstallationId : null,
+#pragma warning restore BWP0001 // Type or member is obsolete
             TaskId = notification.TaskId,
             Title = notification.Title,
             Body = notification.Body,
@@ -246,7 +276,9 @@ public interface IPushNotificationService
         {
             // TODO: Think about this a bit more
             target = NotificationTarget.Installation;
+#pragma warning disable BWP0001 // Type or member is obsolete
             targetId = InstallationId;
+#pragma warning restore BWP0001 // Type or member is obsolete
         }
         else if (notification.UserId.HasValue)
         {
@@ -260,7 +292,9 @@ public interface IPushNotificationService
         }
         else
         {
+#pragma warning disable BWP0001 // Type or member is obsolete
             Logger.LogWarning("Invalid notification id {NotificationId} push notification", notification.Id);
+#pragma warning restore BWP0001 // Type or member is obsolete
             return Task.CompletedTask;
         }
 
@@ -285,7 +319,9 @@ public interface IPushNotificationService
             ClientType = notification.ClientType,
             UserId = notification.UserId,
             OrganizationId = notification.OrganizationId,
+#pragma warning disable BWP0001 // Type or member is obsolete
             InstallationId = notification.Global ? InstallationId : null,
+#pragma warning restore BWP0001 // Type or member is obsolete
             TaskId = notification.TaskId,
             Title = notification.Title,
             Body = notification.Body,
@@ -302,7 +338,9 @@ public interface IPushNotificationService
         {
             // TODO: Think about this a bit more
             target = NotificationTarget.Installation;
+#pragma warning disable BWP0001 // Type or member is obsolete
             targetId = InstallationId;
+#pragma warning restore BWP0001 // Type or member is obsolete
         }
         else if (notification.UserId.HasValue)
         {
@@ -316,7 +354,9 @@ public interface IPushNotificationService
         }
         else
         {
+#pragma warning disable BWP0001 // Type or member is obsolete
             Logger.LogWarning("Invalid notification status id {NotificationId} push notification", notification.Id);
+#pragma warning restore BWP0001 // Type or member is obsolete
             return Task.CompletedTask;
         }
 
@@ -398,7 +438,9 @@ public interface IPushNotificationService
             Payload = new UserPushNotification
             {
                 UserId = userId,
+#pragma warning disable BWP0001 // Type or member is obsolete
                 Date = TimeProvider.GetUtcNow().UtcDateTime,
+#pragma warning restore BWP0001 // Type or member is obsolete
             },
             ExcludeCurrentContext = false,
         });
@@ -406,6 +448,12 @@ public interface IPushNotificationService
 
     Task PushCipherAsync(Cipher cipher, PushType pushType, IEnumerable<Guid>? collectionIds);
 
+    /// <summary>
+    /// Pushes a notification to devices based on the settings given to us in <see cref="PushNotification{T}"/>.
+    /// </summary>
+    /// <typeparam name="T">The type of the payload to be sent along with the notification.</typeparam>
+    /// <param name="pushNotification"></param>
+    /// <returns>A task that is NOT guarunteed to have sent the notification by the time the task resolves.</returns>
     Task PushAsync<T>(PushNotification<T> pushNotification)
         where T : class;
 }

src/Core/Platform/Push/IPushRelayer.cs

@@ -1,6 +1,4 @@
-#nullable enable
+using System.Text.Json;
-
-using System.Text.Json;
 using Bit.Core.Enums;
 
 namespace Bit.Core.Platform.Push.Internal;

src/Core/Platform/Push/NotificationHub/INotificationHubClientProxy.cs

@@ -1,8 +1,6 @@
 using Microsoft.Azure.NotificationHubs;
 
-namespace Bit.Core.NotificationHub;
+namespace Bit.Core.Platform.Push.Internal;
-
-#nullable enable
 
 public interface INotificationHubProxy
 {

src/Core/Platform/Push/NotificationHub/INotificationHubPool.cs

@@ -1,8 +1,6 @@
 using Microsoft.Azure.NotificationHubs;
 
-namespace Bit.Core.NotificationHub;
+namespace Bit.Core.Platform.Push.Internal;
-
-#nullable enable
 
 public interface INotificationHubPool
 {

src/Core/Platform/Push/NotificationHub/NotificationHubClientProxy.cs

@@ -1,8 +1,6 @@
 using Microsoft.Azure.NotificationHubs;
 
-namespace Bit.Core.NotificationHub;
+namespace Bit.Core.Platform.Push.Internal;
-
-#nullable enable
 
 public class NotificationHubClientProxy : INotificationHubProxy
 {

src/Core/Platform/Push/NotificationHub/NotificationHubConnection.cs

@@ -6,9 +6,7 @@ using Bit.Core.Settings;
 using Bit.Core.Utilities;
 using Microsoft.Azure.NotificationHubs;
 
-namespace Bit.Core.NotificationHub;
+namespace Bit.Core.Platform.Push.Internal;
-
-#nullable enable
 
 public class NotificationHubConnection
 {

src/Core/Platform/Push/NotificationHub/NotificationHubPool.cs

@@ -3,9 +3,7 @@ using Bit.Core.Utilities;
 using Microsoft.Azure.NotificationHubs;
 using Microsoft.Extensions.Logging;
 
-namespace Bit.Core.NotificationHub;
+namespace Bit.Core.Platform.Push.Internal;
-
-#nullable enable
 
 public class NotificationHubPool : INotificationHubPool
 {

src/Core/Platform/Push/NotificationHub/NotificationHubPushEngine.cs

@@ -1,28 +1,23 @@
-#nullable enable
+using System.Text.Json;
-using System.Text.Json;
 using System.Text.RegularExpressions;
 using Bit.Core.Context;
 using Bit.Core.Enums;
 using Bit.Core.Models;
 using Bit.Core.Models.Data;
-using Bit.Core.Platform.Push;
-using Bit.Core.Platform.Push.Internal;
 using Bit.Core.Repositories;
 using Bit.Core.Settings;
 using Bit.Core.Vault.Entities;
 using Microsoft.AspNetCore.Http;
 using Microsoft.Extensions.Logging;
 
-namespace Bit.Core.NotificationHub;
+namespace Bit.Core.Platform.Push.Internal;
-
-#nullable enable
 
 /// <summary>
 /// Sends mobile push notifications to the Azure Notification Hub.
 /// Used by Cloud-Hosted environments.
 /// Received by Firebase for Android or APNS for iOS.
 /// </summary>
-public class NotificationHubPushNotificationService : IPushEngine, IPushRelayer
+public class NotificationHubPushEngine : IPushEngine, IPushRelayer
 {
     private readonly IInstallationDeviceRepository _installationDeviceRepository;
     private readonly IHttpContextAccessor _httpContextAccessor;
@@ -30,11 +25,11 @@ public class NotificationHubPushNotificationService : IPushEngine, IPushRelayer
     private readonly INotificationHubPool _notificationHubPool;
     private readonly ILogger _logger;
 
-    public NotificationHubPushNotificationService(
+    public NotificationHubPushEngine(
         IInstallationDeviceRepository installationDeviceRepository,
         INotificationHubPool notificationHubPool,
         IHttpContextAccessor httpContextAccessor,
-        ILogger<NotificationHubPushNotificationService> logger,
+        ILogger<NotificationHubPushEngine> logger,
         IGlobalSettings globalSettings)
     {
         _installationDeviceRepository = installationDeviceRepository;

src/Core/Platform/Push/NotificationInfoAttribute.cs

@@ -0,0 +1,44 @@
+using Bit.Core.Enums;
+
+namespace Bit.Core.Platform.Push;
+
+/// <summary>
+/// Used to annotate information about a given <see cref="PushType"/>.
+/// </summary>
+[AttributeUsage(AttributeTargets.Field)]
+public class NotificationInfoAttribute : Attribute
+{
+    // Once upon a time we can feed this information into a C# analyzer to make sure that we validate
+    // the callsites of IPushNotificationService.PushAsync uses the correct payload type for the notification type
+    // for now this only exists as forced documentation to teams who create a push type.
+
+    // It's especially on purpose that we allow ourselves to take a type name via just the string,
+    // this allows teams to make a push type that is only sent with a payload that exists in a separate assembly than
+    // this one.
+
+    public NotificationInfoAttribute(string team, Type payloadType)
+        // It should be impossible to reference an unnamed type for an attributes constructor so this assertion should be safe.
+        : this(team, payloadType.FullName!)
+    {
+        Team = team;
+    }
+
+    public NotificationInfoAttribute(string team, string payloadTypeName)
+    {
+        ArgumentException.ThrowIfNullOrWhiteSpace(team);
+        ArgumentException.ThrowIfNullOrWhiteSpace(payloadTypeName);
+
+        Team = team;
+        PayloadTypeName = payloadTypeName;
+    }
+
+    /// <summary>
+    /// The name of the team that owns this <see cref="PushType"/>.
+    /// </summary>
+    public string Team { get; }
+
+    /// <summary>
+    /// The fully qualified type name of the payload that should be used when sending a notification of this type.
+    /// </summary>
+    public string PayloadTypeName { get; }
+}

src/Core/Platform/Push/PushNotification.cs

@@ -6,6 +6,9 @@ namespace Bit.Core.Platform.Push;
 /// <summary>
 /// Contains constants for all the available targets for a given notification.
 /// </summary>
+/// <remarks>
+/// Please reach out to the Platform team if you need a new target added.
+/// </remarks>
 public enum NotificationTarget
 {
     /// <summary>

src/Core/Platform/Push/PushServiceCollectionExtensions.cs

@@ -0,0 +1,82 @@
+using Azure.Storage.Queues;
+using Bit.Core.Platform.Push;
+using Bit.Core.Platform.Push.Internal;
+using Bit.Core.Settings;
+using Bit.Core.Utilities;
+using Microsoft.Extensions.DependencyInjection.Extensions;
+
+namespace Microsoft.Extensions.DependencyInjection;
+
+/// <summary>
+/// Extension methods for adding the Push feature.
+/// </summary>
+public static class PushServiceCollectionExtensions
+{
+    /// <summary>
+    /// Adds a <see cref="IPushNotificationService"/> to the services that can be used to send push notifications to
+    /// end user devices. This method is safe to be ran multiple time provided <see cref="GlobalSettings"/> does not 
+    /// change between calls.
+    /// </summary>
+    /// <param name="services">The <see cref="IServiceCollection"/> to add services to.</param>
+    /// <param name="globalSettings">The <see cref="GlobalSettings"/> to use to configure services.</param>
+    /// <returns>The <see cref="IServiceCollection"/> for additional chaining.</returns>
+    public static IServiceCollection AddPush(this IServiceCollection services, GlobalSettings globalSettings)
+    {
+        ArgumentNullException.ThrowIfNull(services);
+        ArgumentNullException.ThrowIfNull(globalSettings);
+
+        services.TryAddSingleton(TimeProvider.System);
+        services.TryAddSingleton<IPushNotificationService, MultiServicePushNotificationService>();
+
+        if (globalSettings.SelfHosted)
+        {
+            if (globalSettings.Installation.Id == Guid.Empty)
+            {
+                throw new InvalidOperationException("Installation Id must be set for self-hosted installations.");
+            }
+
+            if (CoreHelpers.SettingHasValue(globalSettings.PushRelayBaseUri) &&
+                CoreHelpers.SettingHasValue(globalSettings.Installation.Key))
+            {
+                // TODO: We should really define the HttpClient we will use here
+                services.AddHttpClient();
+                services.AddHttpContextAccessor();
+                // We also depend on IDeviceRepository but don't explicitly add it right now.
+                services.TryAddEnumerable(ServiceDescriptor.Singleton<IPushEngine, RelayPushEngine>());
+            }
+
+            if (CoreHelpers.SettingHasValue(globalSettings.InternalIdentityKey) &&
+                CoreHelpers.SettingHasValue(globalSettings.BaseServiceUri.InternalNotifications))
+            {
+                // TODO: We should really define the HttpClient we will use here
+                services.AddHttpClient();
+                services.AddHttpContextAccessor();
+                services.TryAddEnumerable(ServiceDescriptor.Singleton<IPushEngine, NotificationsApiPushEngine>());
+            }
+        }
+        else
+        {
+            services.TryAddSingleton<INotificationHubPool, NotificationHubPool>();
+            services.AddHttpContextAccessor();
+
+            // We also depend on IInstallationDeviceRepository but don't explicitly add it right now.
+            services.TryAddEnumerable(ServiceDescriptor.Singleton<IPushEngine, NotificationHubPushEngine>());
+
+            services.TryAddSingleton<IPushRelayer, NotificationHubPushEngine>();
+
+            if (CoreHelpers.SettingHasValue(globalSettings.Notifications?.ConnectionString))
+            {
+                services.TryAddKeyedSingleton("notifications", static (sp, _) =>
+                {
+                    var gs = sp.GetRequiredService<GlobalSettings>();
+                    return new QueueClient(gs.Notifications.ConnectionString, "notifications");
+                });
+
+                // We not IHttpContextAccessor will be added above, no need to do it here.
+                services.TryAddEnumerable(ServiceDescriptor.Singleton<IPushEngine, AzureQueuePushEngine>());
+            }
+        }
+
+        return services;
+    }
+}

src/Core/Platform/Push/PushType.cs

@@ -0,0 +1,93 @@
+using Bit.Core.Platform.Push;
+
+// TODO: This namespace should change to `Bit.Core.Platform.Push`
+namespace Bit.Core.Enums;
+
+/// <summary>
+/// 
+/// </summary>
+/// <remarks>
+/// <para>
+/// When adding a new enum member you must annotate it with a <see cref="NotificationInfoAttribute"/> 
+/// this is enforced with a unit test. It is preferred that you do NOT add new usings for the type referenced
+/// in <see cref="NotificationInfoAttribute"/>.
+/// </para>
+/// <para>
+/// You may and are 
+/// </para>
+/// </remarks>
+public enum PushType : byte
+{
+    // When adding a new enum member you must annotate it with a NotificationInfoAttribute  this is enforced with a unit
+    // test. It is preferred that you do NOT add new usings for the type referenced for the payload. You are also
+    // encouraged to define the payload type in your own teams owned code.
+
+    [NotificationInfo("@bitwarden/team-vault-dev", typeof(Models.SyncCipherPushNotification))]
+    SyncCipherUpdate = 0,
+
+    [NotificationInfo("@bitwarden/team-vault-dev", typeof(Models.SyncCipherPushNotification))]
+    SyncCipherCreate = 1,
+
+    [NotificationInfo("@bitwarden/team-vault-dev", typeof(Models.SyncCipherPushNotification))]
+    SyncLoginDelete = 2,
+
+    [NotificationInfo("@bitwarden/team-vault-dev", typeof(Models.SyncFolderPushNotification))]
+    SyncFolderDelete = 3,
+
+    [NotificationInfo("@bitwarden/team-vault-dev", typeof(Models.UserPushNotification))]
+    SyncCiphers = 4,
+
+    [NotificationInfo("not-specified", typeof(Models.UserPushNotification))]
+    SyncVault = 5,
+
+    [NotificationInfo("@bitwarden/team-admin-console-dev", typeof(Models.UserPushNotification))]
+    SyncOrgKeys = 6,
+
+    [NotificationInfo("@bitwarden/team-vault-dev", typeof(Models.SyncFolderPushNotification))]
+    SyncFolderCreate = 7,
+
+    [NotificationInfo("@bitwarden/team-vault-dev", typeof(Models.SyncFolderPushNotification))]
+    SyncFolderUpdate = 8,
+
+    [NotificationInfo("@bitwarden/team-vault-dev", typeof(Models.SyncCipherPushNotification))]
+    SyncCipherDelete = 9,
+
+    [NotificationInfo("not-specified", typeof(Models.UserPushNotification))]
+    SyncSettings = 10,
+
+    [NotificationInfo("not-specified", typeof(Models.UserPushNotification))]
+    LogOut = 11,
+
+    [NotificationInfo("@bitwarden/team-tools-dev", typeof(Models.SyncSendPushNotification))]
+    SyncSendCreate = 12,
+
+    [NotificationInfo("@bitwarden/team-tools-dev", typeof(Models.SyncSendPushNotification))]
+    SyncSendUpdate = 13,
+
+    [NotificationInfo("@bitwarden/team-tools-dev", typeof(Models.SyncSendPushNotification))]
+    SyncSendDelete = 14,
+
+    [NotificationInfo("@bitwarden/team-auth-dev", typeof(Models.AuthRequestPushNotification))]
+    AuthRequest = 15,
+
+    [NotificationInfo("@bitwarden/team-auth-dev", typeof(Models.AuthRequestPushNotification))]
+    AuthRequestResponse = 16,
+
+    [NotificationInfo("not-specified", typeof(Models.UserPushNotification))]
+    SyncOrganizations = 17,
+
+    [NotificationInfo("@bitwarden/team-billing-dev", typeof(Models.OrganizationStatusPushNotification))]
+    SyncOrganizationStatusChanged = 18,
+
+    [NotificationInfo("@bitwarden/team-admin-console-dev", typeof(Models.OrganizationCollectionManagementPushNotification))]
+    SyncOrganizationCollectionSettingChanged = 19,
+
+    [NotificationInfo("not-specified", typeof(Models.NotificationPushNotification))]
+    Notification = 20,
+
+    [NotificationInfo("not-specified", typeof(Models.NotificationPushNotification))]
+    NotificationStatus = 21,
+
+    [NotificationInfo("@bitwarden/team-vault-dev", typeof(Models.UserPushNotification))]
+    RefreshSecurityTasks = 22,
+}

src/Core/Platform/PushRegistration/IPushRegistrationService.cs

@@ -1,10 +1,10 @@
-#nullable enable
+using Bit.Core.Enums;
-
+using Bit.Core.Platform.PushRegistration;
-using Bit.Core.Enums;
-using Bit.Core.NotificationHub;
 
+// TODO: Change this namespace to `Bit.Core.Platform.PushRegistration
 namespace Bit.Core.Platform.Push;
 
+
 public interface IPushRegistrationService
 {
     Task CreateOrUpdateRegistrationAsync(PushRegistrationData data, string deviceId, string userId, string identifier, DeviceType type, IEnumerable<string> organizationIds, Guid installationId);

src/Core/Platform/PushRegistration/NoopPushRegistrationService.cs

@@ -1,9 +1,7 @@
-#nullable enable
+using Bit.Core.Enums;
+using Bit.Core.Platform.Push;
 
-using Bit.Core.Enums;
+namespace Bit.Core.Platform.PushRegistration.Internal;
-using Bit.Core.NotificationHub;
-
-namespace Bit.Core.Platform.Push.Internal;
 
 public class NoopPushRegistrationService : IPushRegistrationService
 {

src/Core/Platform/PushRegistration/NotificationHubPushRegistrationService.cs

@@ -6,14 +6,13 @@ using System.Text.Json;
 using Bit.Core.Enums;
 using Bit.Core.Models.Data;
 using Bit.Core.Platform.Push;
+using Bit.Core.Platform.Push.Internal;
 using Bit.Core.Repositories;
 using Bit.Core.Utilities;
 using Microsoft.Azure.NotificationHubs;
 using Microsoft.Extensions.Logging;
 
-namespace Bit.Core.NotificationHub;
+namespace Bit.Core.Platform.PushRegistration.Internal;
-
-#nullable enable
 
 public class NotificationHubPushRegistrationService : IPushRegistrationService
 {

src/Core/Platform/PushRegistration/PushRegistrationData.cs

@@ -1,6 +1,4 @@
-namespace Bit.Core.NotificationHub;
+namespace Bit.Core.Platform.PushRegistration;
-
-#nullable enable
 
 public record struct WebPushRegistrationData
 {

src/Core/Platform/PushRegistration/PushRegistrationServiceCollectionExtensions.cs

@@ -0,0 +1,54 @@
+using Bit.Core.Platform.Push;
+using Bit.Core.Platform.Push.Internal;
+using Bit.Core.Platform.PushRegistration.Internal;
+using Bit.Core.Settings;
+using Bit.Core.Utilities;
+using Microsoft.Extensions.DependencyInjection.Extensions;
+
+namespace Microsoft.Extensions.DependencyInjection;
+
+/// <summary>
+/// Extension methods for adding the Push Registration feature.
+/// </summary>
+public static class PushRegistrationServiceCollectionExtensions
+{
+    /// <summary>
+    /// Adds a <see cref="IPushRegistrationService"/> to the service collection.
+    /// </summary>
+    /// <param name="services">The <see cref="IServiceCollection"/> to add services to.</param>
+    /// <returns>The <see cref="IServiceCollection"/> for chaining.</returns>
+    public static IServiceCollection AddPushRegistration(this IServiceCollection services)
+    {
+        ArgumentNullException.ThrowIfNull(services);
+
+        // TODO: Should add feature that brings in IInstallationDeviceRepository once that is featurized
+
+        // Register all possible variants under there concrete type.
+        services.TryAddSingleton<RelayPushRegistrationService>();
+        services.TryAddSingleton<NoopPushRegistrationService>();
+
+        services.AddHttpClient();
+        services.TryAddSingleton<INotificationHubPool, NotificationHubPool>();
+        services.TryAddSingleton<NotificationHubPushRegistrationService>();
+
+        services.TryAddSingleton<IPushRegistrationService>(static sp =>
+        {
+            var globalSettings = sp.GetRequiredService<GlobalSettings>();
+
+            if (globalSettings.SelfHosted)
+            {
+                if (CoreHelpers.SettingHasValue(globalSettings.PushRelayBaseUri) &&
+                    CoreHelpers.SettingHasValue(globalSettings.Installation.Key))
+                {
+                    return sp.GetRequiredService<RelayPushRegistrationService>();
+                }
+
+                return sp.GetRequiredService<NoopPushRegistrationService>();
+            }
+
+            return sp.GetRequiredService<NotificationHubPushRegistrationService>();
+        });
+
+        return services;
+    }
+}

src/Core/Platform/PushRegistration/RelayPushRegistrationService.cs

@@ -1,14 +1,12 @@
-#nullable enable
+using Bit.Core.Enums;
-
-using Bit.Core.Enums;
 using Bit.Core.IdentityServer;
 using Bit.Core.Models.Api;
-using Bit.Core.NotificationHub;
+using Bit.Core.Platform.Push;
 using Bit.Core.Services;
 using Bit.Core.Settings;
 using Microsoft.Extensions.Logging;
 
-namespace Bit.Core.Platform.Push.Internal;
+namespace Bit.Core.Platform.PushRegistration.Internal;
 
 public class RelayPushRegistrationService : BaseIdentityClientService, IPushRegistrationService
 {

src/Core/Services/IDeviceService.cs

@@ -1,6 +1,6 @@
 using Bit.Core.Auth.Models.Api.Request;
 using Bit.Core.Entities;
-using Bit.Core.NotificationHub;
+using Bit.Core.Platform.PushRegistration;
 
 namespace Bit.Core.Services;
 

src/Core/Services/Implementations/DeviceService.cs

@@ -3,8 +3,8 @@ using Bit.Core.Auth.Utilities;
 using Bit.Core.Entities;
 using Bit.Core.Enums;
 using Bit.Core.Exceptions;
-using Bit.Core.NotificationHub;
 using Bit.Core.Platform.Push;
+using Bit.Core.Platform.PushRegistration;
 using Bit.Core.Repositories;
 using Bit.Core.Settings;
 

src/SharedWeb/Utilities/ServiceCollectionExtensions.cs

@@ -6,7 +6,6 @@ using System.Reflection;
 using System.Security.Claims;
 using System.Security.Cryptography.X509Certificates;
 using AspNetCoreRateLimit;
-using Azure.Storage.Queues;
 using Bit.Core.AdminConsole.Models.Business.Tokenables;
 using Bit.Core.AdminConsole.Models.Data.EventIntegrations;
 using Bit.Core.AdminConsole.OrganizationFeatures.Policies;
@@ -35,11 +34,10 @@ using Bit.Core.Identity;
 using Bit.Core.IdentityServer;
 using Bit.Core.KeyManagement;
 using Bit.Core.NotificationCenter;
-using Bit.Core.NotificationHub;
 using Bit.Core.OrganizationFeatures;
 using Bit.Core.Platform;
 using Bit.Core.Platform.Push;
-using Bit.Core.Platform.Push.Internal;
+using Bit.Core.Platform.PushRegistration.Internal;
 using Bit.Core.Repositories;
 using Bit.Core.Resources;
 using Bit.Core.SecretsManager.Repositories;
@@ -279,46 +277,8 @@ public static class ServiceCollectionExtensions
             services.AddSingleton<IMailDeliveryService, NoopMailDeliveryService>();
         }
 
-        services.TryAddSingleton(TimeProvider.System);
+        services.AddPush(globalSettings);
-
+        services.AddPushRegistration();
-        services.AddSingleton<IPushNotificationService, MultiServicePushNotificationService>();
-        if (globalSettings.SelfHosted)
-        {
-            if (globalSettings.Installation.Id == Guid.Empty)
-            {
-                throw new InvalidOperationException("Installation Id must be set for self-hosted installations.");
-            }
-
-            if (CoreHelpers.SettingHasValue(globalSettings.PushRelayBaseUri) &&
-                CoreHelpers.SettingHasValue(globalSettings.Installation.Key))
-            {
-                services.TryAddEnumerable(ServiceDescriptor.Singleton<IPushEngine, RelayPushNotificationService>());
-                services.AddSingleton<IPushRegistrationService, RelayPushRegistrationService>();
-            }
-            else
-            {
-                services.AddSingleton<IPushRegistrationService, NoopPushRegistrationService>();
-            }
-
-            if (CoreHelpers.SettingHasValue(globalSettings.InternalIdentityKey) &&
-                CoreHelpers.SettingHasValue(globalSettings.BaseServiceUri.InternalNotifications))
-            {
-                services.TryAddEnumerable(ServiceDescriptor.Singleton<IPushEngine, NotificationsApiPushNotificationService>());
-            }
-        }
-        else
-        {
-            services.AddSingleton<INotificationHubPool, NotificationHubPool>();
-            services.AddSingleton<IPushRegistrationService, NotificationHubPushRegistrationService>();
-            services.TryAddEnumerable(ServiceDescriptor.Singleton<IPushEngine, NotificationHubPushNotificationService>());
-            services.TryAddSingleton<IPushRelayer, NotificationHubPushNotificationService>();
-            if (CoreHelpers.SettingHasValue(globalSettings.Notifications?.ConnectionString))
-            {
-                services.AddKeyedSingleton("notifications",
-                    (_, _) => new QueueClient(globalSettings.Notifications.ConnectionString, "notifications"));
-                services.TryAddEnumerable(ServiceDescriptor.Singleton<IPushEngine, AzureQueuePushNotificationService>());
-            }
-        }
 
         if (!globalSettings.SelfHosted && CoreHelpers.SettingHasValue(globalSettings.Mail.ConnectionString))
         {

test/Api.IntegrationTest/Platform/Controllers/PushControllerTests.cs

@@ -8,8 +8,8 @@ using Bit.Core.Enums;
 using Bit.Core.Models;
 using Bit.Core.Models.Api;
 using Bit.Core.Models.Data;
-using Bit.Core.NotificationHub;
 using Bit.Core.Platform.Installations;
+using Bit.Core.Platform.Push.Internal;
 using Bit.Core.Repositories;
 using NSubstitute;
 using Xunit;

test/Api.Test/Platform/Push/Controllers/PushControllerTests.cs

@@ -4,8 +4,8 @@ using Bit.Core.Context;
 using Bit.Core.Enums;
 using Bit.Core.Exceptions;
 using Bit.Core.Models.Api;
-using Bit.Core.NotificationHub;
 using Bit.Core.Platform.Push;
+using Bit.Core.Platform.PushRegistration;
 using Bit.Core.Settings;
 using Bit.Test.Common.AutoFixture;
 using Bit.Test.Common.AutoFixture.Attributes;

test/Core.Test/Platform/Push/Engines/AzureQueuePushEngineTests.cs

@@ -22,18 +22,18 @@ using Microsoft.Extensions.Time.Testing;
 using NSubstitute;
 using Xunit;
 
-namespace Bit.Core.Test.Platform.Push.Services;
+namespace Bit.Core.Test.Platform.Push.Engines;
 
 [QueueClientCustomize]
 [SutProviderCustomize]
-public class AzureQueuePushNotificationServiceTests
+public class AzureQueuePushEngineTests
 {
     private static readonly Guid _deviceId = Guid.Parse("c4730f80-caaa-4772-97bd-5c0d23a2baa3");
     private static readonly string _deviceIdentifier = "test_device_identifier";
     private readonly FakeTimeProvider _fakeTimeProvider;
     private readonly Core.Settings.GlobalSettings _globalSettings = new();
 
-    public AzureQueuePushNotificationServiceTests()
+    public AzureQueuePushEngineTests()
     {
         _fakeTimeProvider = new();
         _fakeTimeProvider.SetUtcNow(DateTime.UtcNow);
@@ -771,12 +771,11 @@ public class AzureQueuePushNotificationServiceTests
 
         var globalSettings = new Core.Settings.GlobalSettings();
 
-        var sut = new AzureQueuePushNotificationService(
+        var sut = new AzureQueuePushEngine(
             queueClient,
             httpContextAccessor,
             globalSettings,
-            NullLogger<AzureQueuePushNotificationService>.Instance,
+            NullLogger<AzureQueuePushEngine>.Instance
-            _fakeTimeProvider
         );
 
         await test(new EngineWrapper(sut, _fakeTimeProvider, _globalSettings.Installation.Id));

test/Core.Test/Platform/Push/Engines/NotificationsApiPushEngineTests.cs

@@ -2,16 +2,16 @@
 using Bit.Core.AdminConsole.Entities;
 using Bit.Core.Auth.Entities;
 using Bit.Core.NotificationCenter.Entities;
-using Bit.Core.Platform.Push;
+using Bit.Core.Platform.Push.Internal;
 using Bit.Core.Tools.Entities;
 using Bit.Core.Vault.Entities;
 using Microsoft.Extensions.Logging.Abstractions;
 
-namespace Bit.Core.Test.Platform.Push.Services;
+namespace Bit.Core.Test.Platform.Push.Engines;
 
-public class NotificationsApiPushNotificationServiceTests : PushTestBase
+public class NotificationsApiPushEngineTests : PushTestBase
 {
-    public NotificationsApiPushNotificationServiceTests()
+    public NotificationsApiPushEngineTests()
     {
         GlobalSettings.BaseServiceUri.InternalNotifications = "https://localhost:7777";
         GlobalSettings.BaseServiceUri.InternalIdentity = "https://localhost:8888";
@@ -21,11 +21,11 @@ public class NotificationsApiPushNotificationServiceTests : PushTestBase
 
     protected override IPushEngine CreateService()
     {
-        return new NotificationsApiPushNotificationService(
+        return new NotificationsApiPushEngine(
             HttpClientFactory,
             GlobalSettings,
             HttpContextAccessor,
-            NullLogger<NotificationsApiPushNotificationService>.Instance
+            NullLogger<NotificationsApiPushEngine>.Instance
         );
     }
 

test/Core.Test/Platform/Push/Engines/PushTestBase.cs

@@ -10,6 +10,7 @@ using Bit.Core.Enums;
 using Bit.Core.NotificationCenter.Entities;
 using Bit.Core.NotificationCenter.Enums;
 using Bit.Core.Platform.Push;
+using Bit.Core.Platform.Push.Internal;
 using Bit.Core.Settings;
 using Bit.Core.Tools.Entities;
 using Bit.Core.Vault.Entities;
@@ -22,6 +23,8 @@ using NSubstitute;
 using RichardSzalay.MockHttp;
 using Xunit;
 
+namespace Bit.Core.Test.Platform.Push.Engines;
+
 public class EngineWrapper(IPushEngine pushEngine, FakeTimeProvider fakeTimeProvider, Guid installationId) : IPushNotificationService
 {
     public Guid InstallationId { get; } = installationId;

test/Core.Test/Platform/Push/Engines/RelayPushEngineTests.cs

@@ -5,7 +5,6 @@ using Bit.Core.AdminConsole.Entities;
 using Bit.Core.Auth.Entities;
 using Bit.Core.Entities;
 using Bit.Core.NotificationCenter.Entities;
-using Bit.Core.Platform.Push;
 using Bit.Core.Platform.Push.Internal;
 using Bit.Core.Repositories;
 using Bit.Core.Settings;
@@ -15,7 +14,7 @@ using Microsoft.Extensions.Logging.Abstractions;
 using Microsoft.Extensions.Time.Testing;
 using NSubstitute;
 
-namespace Bit.Core.Test.Platform.Push.Services;
+namespace Bit.Core.Test.Platform.Push.Engines;
 
 public class RelayPushNotificationServiceTests : PushTestBase
 {
@@ -39,12 +38,12 @@ public class RelayPushNotificationServiceTests : PushTestBase
 
     protected override IPushEngine CreateService()
     {
-        return new RelayPushNotificationService(
+        return new RelayPushEngine(
             HttpClientFactory,
             _deviceRepository,
             GlobalSettings,
             HttpContextAccessor,
-            NullLogger<RelayPushNotificationService>.Instance
+            NullLogger<RelayPushEngine>.Instance
         );
     }
 

test/Core.Test/Platform/Push/MultiServicePushNotificationServiceTests.cs

@@ -0,0 +1,57 @@
+using Bit.Core.Enums;
+using Bit.Core.Platform.Push;
+using Bit.Core.Platform.Push.Internal;
+using Bit.Core.Settings;
+using Microsoft.Extensions.Logging.Abstractions;
+using Microsoft.Extensions.Time.Testing;
+using NSubstitute;
+using Xunit;
+
+namespace Bit.Core.Test.Platform.Push;
+
+public class MultiServicePushNotificationServiceTests
+{
+    private readonly IPushEngine _fakeEngine1;
+    private readonly IPushEngine _fakeEngine2;
+
+    private readonly MultiServicePushNotificationService _sut;
+
+    public MultiServicePushNotificationServiceTests()
+    {
+        _fakeEngine1 = Substitute.For<IPushEngine>();
+        _fakeEngine2 = Substitute.For<IPushEngine>();
+
+        _sut = new MultiServicePushNotificationService(
+            [_fakeEngine1, _fakeEngine2],
+            NullLogger<MultiServicePushNotificationService>.Instance,
+            new GlobalSettings(),
+            new FakeTimeProvider()
+        );
+    }
+
+#if DEBUG // This test requires debug code in the sut to work properly
+    [Fact]
+    public async Task PushAsync_CallsAllEngines()
+    {
+        var notification = new PushNotification<object>
+        {
+            Target = NotificationTarget.User,
+            TargetId = Guid.NewGuid(),
+            Type = PushType.AuthRequest,
+            Payload = new { },
+            ExcludeCurrentContext = false,
+        };
+
+        await _sut.PushAsync(notification);
+
+        await _fakeEngine1
+            .Received(1)
+            .PushAsync(Arg.Is<PushNotification<object>>(n => ReferenceEquals(n, notification)));
+
+        await _fakeEngine2
+            .Received(1)
+            .PushAsync(Arg.Is<PushNotification<object>>(n => ReferenceEquals(n, notification)));
+    }
+
+#endif
+}

test/Core.Test/Platform/Push/NotificationHub/NotificationHubConnectionTests.cs

@@ -1,9 +1,9 @@
-using Bit.Core.NotificationHub;
+using Bit.Core.Platform.Push.Internal;
 using Bit.Core.Settings;
 using Bit.Core.Utilities;
 using Xunit;
 
-namespace Bit.Core.Test.NotificationHub;
+namespace Bit.Core.Test.Platform.Push.NotificationHub;
 
 public class NotificationHubConnectionTests
 {

test/Core.Test/Platform/Push/NotificationHub/NotificationHubPoolTests.cs

@@ -1,4 +1,4 @@
-using Bit.Core.NotificationHub;
+using Bit.Core.Platform.Push.Internal;
 using Bit.Core.Settings;
 using Bit.Core.Utilities;
 using Microsoft.Extensions.Logging;
@@ -6,7 +6,7 @@ using NSubstitute;
 using Xunit;
 using static Bit.Core.Settings.GlobalSettings;
 
-namespace Bit.Core.Test.NotificationHub;
+namespace Bit.Core.Test.Platform.Push.NotificationHub;
 
 public class NotificationHubPoolTests
 {

test/Core.Test/Platform/Push/NotificationHub/NotificationHubProxyTests.cs

@@ -1,11 +1,11 @@
 using AutoFixture;
-using Bit.Core.NotificationHub;
+using Bit.Core.Platform.Push.Internal;
 using Bit.Test.Common.AutoFixture;
 using Microsoft.Azure.NotificationHubs;
 using NSubstitute;
 using Xunit;
 
-namespace Bit.Core.Test.NotificationHub;
+namespace Bit.Core.Test.Platform.Push.NotificationHub;
 
 public class NotificationHubProxyTests
 {

test/Core.Test/Platform/Push/NotificationHub/NotificationHubPushEngineTests.cs

@@ -1,5 +1,4 @@
-#nullable enable
+using System.Text.Json;
-using System.Text.Json;
 using System.Text.Json.Nodes;
 using Bit.Core.Auth.Entities;
 using Bit.Core.Context;
@@ -7,10 +6,11 @@ using Bit.Core.Enums;
 using Bit.Core.Models;
 using Bit.Core.NotificationCenter.Entities;
 using Bit.Core.NotificationCenter.Enums;
-using Bit.Core.NotificationHub;
 using Bit.Core.Platform.Push;
+using Bit.Core.Platform.Push.Internal;
 using Bit.Core.Repositories;
 using Bit.Core.Test.NotificationCenter.AutoFixture;
+using Bit.Core.Test.Platform.Push.Engines;
 using Bit.Core.Tools.Entities;
 using Bit.Core.Vault.Entities;
 using Bit.Test.Common.AutoFixture;
@@ -22,7 +22,7 @@ using Microsoft.Extensions.Time.Testing;
 using NSubstitute;
 using Xunit;
 
-namespace Bit.Core.Test.NotificationHub;
+namespace Bit.Core.Test.Platform.Push.NotificationHub;
 
 [SutProviderCustomize]
 [NotificationStatusCustomize]
@@ -621,11 +621,11 @@ public class NotificationHubPushNotificationServiceTests
 
         fakeTimeProvider.SetUtcNow(_now);
 
-        var sut = new NotificationHubPushNotificationService(
+        var sut = new NotificationHubPushEngine(
             installationDeviceRepository,
             notificationHubPool,
             httpContextAccessor,
-            NullLogger<NotificationHubPushNotificationService>.Instance,
+            NullLogger<NotificationHubPushEngine>.Instance,
             globalSettings
         );
 
@@ -676,7 +676,7 @@ public class NotificationHubPushNotificationServiceTests
         };
 
     private static async Task AssertSendTemplateNotificationAsync(
-        SutProvider<NotificationHubPushNotificationService> sutProvider, PushType type, object payload, string tag)
+        SutProvider<NotificationHubPushEngine> sutProvider, PushType type, object payload, string tag)
     {
         await sutProvider.GetDependency<INotificationHubPool>()
             .Received(1)

test/Core.Test/Platform/Push/PushServiceCollectionExtensionsTests.cs

@@ -0,0 +1,198 @@
+using Bit.Core.Auth.Models.Data;
+using Bit.Core.Entities;
+using Bit.Core.KeyManagement.UserKey;
+using Bit.Core.Platform.Push;
+using Bit.Core.Platform.Push.Internal;
+using Bit.Core.Repositories;
+using Bit.Core.Repositories.Noop;
+using Bit.Core.Settings;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.DependencyInjection.Extensions;
+using Xunit;
+
+namespace Bit.Core.Test.Platform.Push;
+
+public class PushServiceCollectionExtensionsTests
+{
+    [Fact]
+    public void AddPush_SelfHosted_NoConfig_NoEngines()
+    {
+        var services = Build(new Dictionary<string, string?>
+        {
+            { "GlobalSettings:SelfHosted", "true" },
+            { "GlobalSettings:Installation:Id", Guid.NewGuid().ToString() },
+        });
+
+        _ = services.GetRequiredService<IPushNotificationService>();
+        var engines = services.GetServices<IPushEngine>();
+
+        Assert.Empty(engines);
+    }
+
+    [Fact]
+    public void AddPush_SelfHosted_ConfiguredForRelay_RelayEngineAdded()
+    {
+        var services = Build(new Dictionary<string, string?>
+        {
+            { "GlobalSettings:SelfHosted", "true" },
+            { "GlobalSettings:Installation:Id", Guid.NewGuid().ToString() },
+            { "GlobalSettings:Installation:Key", "some_key"},
+            { "GlobalSettings:PushRelayBaseUri", "https://example.com" },
+        });
+
+        _ = services.GetRequiredService<IPushNotificationService>();
+        var engines = services.GetServices<IPushEngine>();
+
+        var engine = Assert.Single(engines);
+        Assert.IsType<RelayPushEngine>(engine);
+    }
+
+    [Fact]
+    public void AddPush_SelfHosted_ConfiguredForApi_ApiEngineAdded()
+    {
+        var services = Build(new Dictionary<string, string?>
+        {
+            { "GlobalSettings:SelfHosted", "true" },
+            { "GlobalSettings:Installation:Id", Guid.NewGuid().ToString() },
+            { "GlobalSettings:InternalIdentityKey", "some_key"},
+            { "GlobalSettings:BaseServiceUri", "https://example.com" },
+        });
+
+        _ = services.GetRequiredService<IPushNotificationService>();
+        var engines = services.GetServices<IPushEngine>();
+
+        var engine = Assert.Single(engines);
+        Assert.IsType<NotificationsApiPushEngine>(engine);
+    }
+
+    [Fact]
+    public void AddPush_SelfHosted_ConfiguredForRelayAndApi_TwoEnginesAdded()
+    {
+        var services = Build(new Dictionary<string, string?>
+        {
+            { "GlobalSettings:SelfHosted", "true" },
+            { "GlobalSettings:Installation:Id", Guid.NewGuid().ToString() },
+            { "GlobalSettings:Installation:Key", "some_key"},
+            { "GlobalSettings:PushRelayBaseUri", "https://example.com" },
+            { "GlobalSettings:InternalIdentityKey", "some_key"},
+            { "GlobalSettings:BaseServiceUri", "https://example.com" },
+        });
+
+        _ = services.GetRequiredService<IPushNotificationService>();
+        var engines = services.GetServices<IPushEngine>();
+
+        Assert.Collection(
+            engines,
+            e => Assert.IsType<RelayPushEngine>(e),
+            e => Assert.IsType<NotificationsApiPushEngine>(e)
+        );
+    }
+
+    [Fact]
+    public void AddPush_Cloud_NoConfig_AddsNotificationHub()
+    {
+        var services = Build(new Dictionary<string, string?>
+        {
+            { "GlobalSettings:SelfHosted", "false" },
+        });
+
+        _ = services.GetRequiredService<IPushNotificationService>();
+        var engines = services.GetServices<IPushEngine>();
+
+        var engine = Assert.Single(engines);
+        Assert.IsType<NotificationHubPushEngine>(engine);
+    }
+
+    [Fact]
+    public void AddPush_Cloud_HasNotificationConnectionString_TwoEngines()
+    {
+        var services = Build(new Dictionary<string, string?>
+        {
+            { "GlobalSettings:SelfHosted", "false" },
+            { "GlobalSettings:Notifications:ConnectionString", "UseDevelopmentStorage=true" },
+        });
+
+        _ = services.GetRequiredService<IPushNotificationService>();
+        var engines = services.GetServices<IPushEngine>();
+
+        Assert.Collection(
+            engines,
+            e => Assert.IsType<NotificationHubPushEngine>(e),
+            e => Assert.IsType<AzureQueuePushEngine>(e)
+        );
+    }
+
+    [Fact]
+    public void AddPush_Cloud_CalledTwice_DoesNotAddServicesTwice()
+    {
+        var services = new ServiceCollection();
+
+        var config = new Dictionary<string, string?>
+        {
+            { "GlobalSettings:SelfHosted", "false" },
+            { "GlobalSettings:Notifications:ConnectionString", "UseDevelopmentStorage=true" },
+        };
+
+        AddServices(services, config);
+
+        var initialCount = services.Count;
+
+        // Add services again
+        AddServices(services, config);
+
+        Assert.Equal(initialCount, services.Count);
+    }
+
+    private static ServiceProvider Build(Dictionary<string, string?> initialData)
+    {
+        var services = new ServiceCollection();
+
+        AddServices(services, initialData);
+
+        return services.BuildServiceProvider();
+    }
+
+    private static void AddServices(IServiceCollection services, Dictionary<string, string?> initialData)
+    {
+        // A minimal service collection is always expected to have logging, config, and global settings
+        // pre-registered. 
+
+        services.AddLogging();
+
+        var config = new ConfigurationBuilder()
+            .AddInMemoryCollection(initialData)
+            .Build();
+
+        services.TryAddSingleton(config);
+        var globalSettings = new GlobalSettings();
+        config.GetSection("GlobalSettings").Bind(globalSettings);
+
+        services.TryAddSingleton(globalSettings);
+        services.TryAddSingleton<IGlobalSettings>(globalSettings);
+
+        // Temporary until AddPush can add it themselves directly.
+        services.TryAddSingleton<IDeviceRepository, StubDeviceRepository>();
+
+        // Temporary until AddPush can add it themselves directly.
+        services.TryAddSingleton<IInstallationDeviceRepository, InstallationDeviceRepository>();
+
+        services.AddPush(globalSettings);
+    }
+
+    private class StubDeviceRepository : IDeviceRepository
+    {
+        public Task ClearPushTokenAsync(Guid id) => throw new NotImplementedException();
+        public Task<Device> CreateAsync(Device obj) => throw new NotImplementedException();
+        public Task DeleteAsync(Device obj) => throw new NotImplementedException();
+        public Task<Device?> GetByIdAsync(Guid id, Guid userId) => throw new NotImplementedException();
+        public Task<Device?> GetByIdAsync(Guid id) => throw new NotImplementedException();
+        public Task<Device?> GetByIdentifierAsync(string identifier) => throw new NotImplementedException();
+        public Task<Device?> GetByIdentifierAsync(string identifier, Guid userId) => throw new NotImplementedException();
+        public Task<ICollection<Device>> GetManyByUserIdAsync(Guid userId) => throw new NotImplementedException();
+        public Task<ICollection<DeviceAuthDetails>> GetManyByUserIdWithDeviceAuth(Guid userId) => throw new NotImplementedException();
+        public Task ReplaceAsync(Device obj) => throw new NotImplementedException();
+        public UpdateEncryptedDataForKeyRotation UpdateKeysForRotationAsync(Guid userId, IEnumerable<Device> devices) => throw new NotImplementedException();
+        public Task UpsertAsync(Device obj) => throw new NotImplementedException();
+    }
+}

test/Core.Test/Platform/Push/PushTypeTests.cs

@@ -0,0 +1,64 @@
+using System.Diagnostics;
+using System.Reflection;
+using Bit.Core.Enums;
+using Bit.Core.Platform.Push;
+using Xunit;
+
+namespace Bit.Core.Test.Platform.Push;
+
+public class PushTypeTests
+{
+    [Fact]
+    public void AllEnumMembersHaveUniqueValue()
+    {
+        // No enum member should use the same value as another named member.
+
+        var usedNumbers = new HashSet<byte>();
+        var enumMembers = Enum.GetValues<PushType>();
+
+        foreach (var enumMember in enumMembers)
+        {
+            if (!usedNumbers.Add((byte)enumMember))
+            {
+                Assert.Fail($"Enum number value ({(byte)enumMember}) on {enumMember} is already in use.");
+            }
+        }
+    }
+
+    [Fact]
+    public void AllEnumMembersHaveNotificationInfoAttribute()
+    {
+        // Every enum member should be annotated with [NotificationInfo]
+
+        foreach (var member in typeof(PushType).GetMembers(BindingFlags.Public | BindingFlags.Static))
+        {
+            var notificationInfoAttribute = member.GetCustomAttribute<NotificationInfoAttribute>();
+            if (notificationInfoAttribute is null)
+            {
+                Assert.Fail($"PushType.{member.Name} is missing a required [NotificationInfo(\"team-name\", typeof(MyType))] attribute.");
+            }
+        }
+    }
+
+    [Fact]
+    public void AllEnumValuesAreInSequence()
+    {
+        // There should not be any gaps in the numbers defined for an enum, that being if someone last defined 22
+        // the next number used should be 23 not 24 or any other number.
+
+        var sortedValues = Enum.GetValues<PushType>()
+            .Order()
+            .ToArray();
+
+        Debug.Assert(sortedValues.Length > 0);
+
+        var lastValue = sortedValues[0];
+
+        foreach (var value in sortedValues[1..])
+        {
+            var expectedValue = ++lastValue;
+
+            Assert.Equal(expectedValue, value);
+        }
+    }
+}

test/Core.Test/Platform/Push/Services/MultiServicePushNotificationServiceTests.cs

@@ -1,8 +0,0 @@
-#nullable enable
-
-namespace Bit.Core.Test.Platform.Push.Services;
-
-public class MultiServicePushNotificationServiceTests
-{
-    // TODO: Can add a couple tests here
-}

test/Core.Test/Platform/PushRegistration/NotificationHubPushRegistrationServiceTests.cs

@@ -1,6 +1,8 @@
 #nullable enable
 using Bit.Core.Enums;
-using Bit.Core.NotificationHub;
+using Bit.Core.Platform.Push.Internal;
+using Bit.Core.Platform.PushRegistration;
+using Bit.Core.Platform.PushRegistration.Internal;
 using Bit.Core.Utilities;
 using Bit.Test.Common.AutoFixture;
 using Bit.Test.Common.AutoFixture.Attributes;

test/Core.Test/Platform/PushRegistration/PushRegistrationServiceCollectionExtensionsTests.cs

@@ -0,0 +1,108 @@
+using Bit.Core.Platform.Push;
+using Bit.Core.Platform.PushRegistration.Internal;
+using Bit.Core.Repositories;
+using Bit.Core.Repositories.Noop;
+using Bit.Core.Settings;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.DependencyInjection.Extensions;
+using Xunit;
+
+namespace Bit.Core.Test.Platform.PushRegistration;
+
+public class PushRegistrationServiceCollectionExtensionsTests
+{
+    [Fact]
+    public void AddPushRegistration_Cloud_CreatesNotificationHubRegistrationService()
+    {
+        var services = Build(new Dictionary<string, string?>
+        {
+            { "GlobalSettings:SelfHosted", "false" },
+        });
+
+        var pushRegistrationService = services.GetRequiredService<IPushRegistrationService>();
+        Assert.IsType<NotificationHubPushRegistrationService>(pushRegistrationService);
+    }
+
+    [Fact]
+    public void AddPushRegistration_SelfHosted_NoOtherConfig_ReturnsNoopRegistrationService()
+    {
+        var services = Build(new Dictionary<string, string?>
+        {
+            { "GlobalSettings:SelfHosted", "true" },
+        });
+
+        var pushRegistrationService = services.GetRequiredService<IPushRegistrationService>();
+        Assert.IsType<NoopPushRegistrationService>(pushRegistrationService);
+    }
+
+    [Fact]
+    public void AddPushRegistration_SelfHosted_RelayConfig_ReturnsRelayRegistrationService()
+    {
+        var services = Build(new Dictionary<string, string?>
+        {
+            { "GlobalSettings:SelfHosted", "true" },
+            { "GlobalSettings:PushRelayBaseUri", "https://example.com" },
+            { "GlobalSettings:Installation:Key", "some_key" },
+        });
+
+        var pushRegistrationService = services.GetRequiredService<IPushRegistrationService>();
+        Assert.IsType<RelayPushRegistrationService>(pushRegistrationService);
+    }
+
+    [Fact]
+    public void AddPushRegistration_MultipleTimes_NoAdditionalServices()
+    {
+        var services = new ServiceCollection();
+
+        var config = new Dictionary<string, string?>
+        {
+            { "GlobalSettings:SelfHosted", "true" },
+            { "GlobalSettings:PushRelayBaseUri", "https://example.com" },
+            { "GlobalSettings:Installation:Key", "some_key" },
+        };
+
+        AddServices(services, config);
+
+        // Add services again
+        services.AddPushRegistration();
+
+        var provider = services.BuildServiceProvider();
+
+        Assert.Single(provider.GetServices<IPushRegistrationService>());
+    }
+
+    private static ServiceProvider Build(Dictionary<string, string?> initialData)
+    {
+        var services = new ServiceCollection();
+
+        AddServices(services, initialData);
+
+        return services.BuildServiceProvider();
+    }
+
+    private static void AddServices(IServiceCollection services, Dictionary<string, string?> initialData)
+    {
+        // A minimal service collection is always expected to have logging, config, and global settings
+        // pre-registered. 
+
+        services.AddLogging();
+
+        var config = new ConfigurationBuilder()
+            .AddInMemoryCollection(initialData)
+            .Build();
+
+        services.TryAddSingleton(config);
+        var globalSettings = new GlobalSettings();
+        config.GetSection("GlobalSettings").Bind(globalSettings);
+
+        services.TryAddSingleton(globalSettings);
+        services.TryAddSingleton<IGlobalSettings>(globalSettings);
+
+
+        // Temporary until AddPushRegistration can add it themselves directly.
+        services.TryAddSingleton<IInstallationDeviceRepository, InstallationDeviceRepository>();
+
+        services.AddPushRegistration();
+    }
+}

test/Core.Test/Platform/PushRegistration/RelayPushRegistrationServiceTests.cs

@@ -1,4 +1,4 @@
-using Bit.Core.Platform.Push.Internal;
+using Bit.Core.Platform.PushRegistration.Internal;
 using Bit.Core.Settings;
 using Microsoft.Extensions.Logging;
 using NSubstitute;

test/Core.Test/Services/DeviceServiceTests.cs

@@ -4,8 +4,8 @@ using Bit.Core.Entities;
 using Bit.Core.Enums;
 using Bit.Core.Exceptions;
 using Bit.Core.Models.Data.Organizations.OrganizationUsers;
-using Bit.Core.NotificationHub;
 using Bit.Core.Platform.Push;
+using Bit.Core.Platform.PushRegistration;
 using Bit.Core.Repositories;
 using Bit.Core.Services;
 using Bit.Core.Settings;

test/IntegrationTestCommon/Factories/WebApplicationFactoryBase.cs

@@ -2,7 +2,7 @@
 using Bit.Core.Billing.Organizations.Services;
 using Bit.Core.Billing.Services;
 using Bit.Core.Platform.Push;
-using Bit.Core.Platform.Push.Internal;
+using Bit.Core.Platform.PushRegistration.Internal;
 using Bit.Core.Repositories;
 using Bit.Core.Services;
 using Bit.Infrastructure.EntityFramework.Repositories;