feat(push): add service-owned firebase channels and delivery

Add push contracts, provider delivery and channel diagnostics. Link email channels to services and document migration and validation.

Ref: IT-1074

HrynCo.NotificationService.Worker/Program.cs

@@ -20,5 +20,18 @@ builder.Services.Configure<RabbitMqSettings>(
 
 builder.Services.AddHostedService<SendEmailConsumer>();
 
+var pushSettings = builder.Configuration.GetSection("FcmPush")
+    .Get<HrynCo.NotificationService.Worker.Services.Push.FcmPushSettings>() ?? new();
+builder.Services.AddSingleton(pushSettings);
+if (pushSettings.Enabled)
+{
+    builder.Services.AddScoped<HrynCo.NotificationService.Worker.Services.Push.IFirebasePushClient,
+        HrynCo.NotificationService.Worker.Services.Push.FirebasePushClient>();
+    builder.Services.AddScoped<HrynCo.NotificationService.Worker.Services.Push.IPushSender,
+        HrynCo.NotificationService.Worker.Services.Push.FcmPushSender>();
+    builder.Services.AddScoped<HrynCo.NotificationService.Worker.Services.Push.PushDeliveryService>();
+    builder.Services.AddHostedService<SendPushConsumer>();
+}
+
 var host = builder.Build();
 host.Run();

HrynCo.NotificationService.Worker/SendEmailConsumer.cs

@@ -8,7 +8,6 @@ using Microsoft.Extensions.Options;
 public sealed class SendEmailConsumer : RabbitMqConsumerBase<SendEmailMessage, SendEmailMessageData>
 {
     internal const string IncomingQueue = "notification.send-email";
-    internal const string SupportedMessageType = "Notification.SendEmail.v1";
 
     private readonly IServiceScopeFactory _scopeFactory;
     private readonly ILogger<SendEmailConsumer> _logger;
@@ -33,7 +32,7 @@ public sealed class SendEmailConsumer : RabbitMqConsumerBase<SendEmailMessage, S
         validationError = SendEmailDeliveryValidator.GetValidationError(
             message,
             context,
-            SupportedMessageType);
+            SupportedMessageType.SendEmailV1);
         return validationError is null;
     }
 

HrynCo.NotificationService.Worker/SendEmailDeliveryValidator.cs

@@ -9,12 +9,12 @@ internal static class SendEmailDeliveryValidator
     public static string? GetValidationError(
         SendEmailMessage message,
         RabbitMqMessageContext context,
-        string supportedMessageType)
+        SupportedMessageType supportedMessageType)
     {
         if (string.IsNullOrWhiteSpace(context.MessageId))
             return "AMQP MessageId is required.";
 
-        if (!string.Equals(context.MessageType, supportedMessageType, StringComparison.Ordinal))
+        if (SupportedMessageTypeParser.Parse(context.MessageType) != supportedMessageType)
             return $"Unsupported AMQP message type '{context.MessageType ?? "<missing>"}'.";
 
         try

HrynCo.NotificationService.Worker/SendPushConsumer.cs

@@ -0,0 +1,37 @@
+namespace HrynCo.NotificationService.Worker;
+
+using HrynCo.NotificationService.Contracts.Messages;
+using HrynCo.NotificationService.Worker.Services.Push;
+using Hrynco.RabbitMq;
+using Microsoft.Extensions.Options;
+
+public sealed class SendPushConsumer(
+    IOptionsMonitor<RabbitMqSettings> options, IServiceScopeFactory scopes,
+    ILogger<SendPushConsumer> logger)
+    : RabbitMqConsumerBase<SendPushMessage, SendPushMessageData>(options, logger)
+{
+    protected override string QueueName => "notification.send-push";
+
+    protected override bool TryValidateMessage(SendPushMessage message, RabbitMqMessageContext context, out string? validationError)
+    {
+        bool valid = SendPushDeliveryValidator.IsValid(message, context);
+        validationError = valid ? null : "Invalid push envelope.";
+        return valid;
+    }
+
+    protected override async Task HandleMessageAsync(SendPushMessage message, RabbitMqMessageContext context,
+        CancellationToken cancellationToken)
+    {
+        await using var scope = scopes.CreateAsyncScope();
+        await scope.ServiceProvider.GetRequiredService<PushDeliveryService>()
+            .ProcessAsync(Guid.Parse(context.MessageId!), message, cancellationToken);
+    }
+
+    protected override async Task HandleMessageRetriesExhaustedAsync(SendPushMessage message,
+        RabbitMqMessageContext context, Exception exception, CancellationToken cancellationToken)
+    {
+        await using var scope = scopes.CreateAsyncScope();
+        await scope.ServiceProvider.GetRequiredService<PushDeliveryService>()
+            .CompleteFailureAsync(Guid.Parse(context.MessageId!), message, cancellationToken);
+    }
+}

HrynCo.NotificationService.Worker/SendPushDeliveryValidator.cs

@@ -0,0 +1,13 @@
+namespace HrynCo.NotificationService.Worker;
+
+using HrynCo.NotificationService.Contracts.Messages;
+using HrynCo.NotificationService.Worker.Services.Push;
+using Hrynco.RabbitMq;
+
+internal static class SendPushDeliveryValidator
+{
+    public static bool IsValid(SendPushMessage message, RabbitMqMessageContext context) =>
+        SupportedMessageTypeParser.Parse(context.MessageType) == SupportedMessageType.SendPushV1 &&
+        Guid.TryParse(context.MessageId, out _) && context.MessageId == message.CorrelationContext?.CorrelationId &&
+        PushMessageValidator.IsValid(message);
+}

HrynCo.NotificationService.Worker/SupportedMessageTypeParser.cs

@@ -0,0 +1,13 @@
+namespace HrynCo.NotificationService.Worker;
+
+using HrynCo.NotificationService.Contracts.Messages;
+
+internal static class SupportedMessageTypeParser
+{
+    public static SupportedMessageType? Parse(string? value) => value switch
+    {
+        "Notification.SendEmail.v1" => SupportedMessageType.SendEmailV1,
+        "Notification.SendPush.v1" => SupportedMessageType.SendPushV1,
+        _ => null
+    };
+}