hrynco-notification-service/HrynCo.NotificationService.Worker.Services/Push/FcmPushSender.cs

using System.Security.Cryptography;
using System.Text.Json;
using HrynCo.NotificationService.Contracts.Messages;
using HrynCo.NotificationService.DAL.Abstract.Push;
using HrynCo.NotificationService.DAL.Abstract.PushChannels;
using HrynCo.NotificationService.DAL.Abstract.Repositories;

namespace HrynCo.NotificationService.Worker.Services.Push;

public sealed class FcmPushSender(
    INotificationServiceRepository services, IPushChannelRepository channels, IFirebasePushClient client) : IPushSender
{
    public async Task<PushDeliveryOutcome> SendAsync(Guid messageId, SendPushMessageData data, CancellationToken cancellationToken)
    {
        if (data.ExpiresAt <= DateTimeOffset.UtcNow) return new PushDeliveryOutcome("Push expired.");
        var service = await services.GetByNameAsync(data.ServiceName, cancellationToken);
        if (service is null) return new PushDeliveryOutcome("Push service is not configured.");
        var channel = await channels.GetActiveForServiceAsync(service.Id, cancellationToken);
        if (channel is null) return new PushDeliveryOutcome("No active push channel is configured for this service.");
        var credentials = await channels.GetCredentialsAsync(channel.Id, cancellationToken);
        return await SendWithCredentialsAsync(messageId, data, channel.FirebaseProjectId, credentials, cancellationToken);
    }

    private async Task<PushDeliveryOutcome> SendWithCredentialsAsync(Guid messageId, SendPushMessageData data,
        string projectId, string? json, CancellationToken ct)
    {
        try
        {
            var credentials = FirebaseServiceAccountCredentials.Parse(json ?? string.Empty, projectId);
            return await client.SendAsync(messageId, data, credentials, ct);
        }
        catch (Exception error) when (error is JsonException or FormatException or ArgumentException or CryptographicException)
        {
            // Never propagate credential parser details into broker retry logs or replies.
            return new PushDeliveryOutcome("The push channel Firebase configuration is invalid.");
        }
    }
}