feat(Backend): update API gateway and websocket hubs

FinlyticBackend/Services/FirebaseNotificationService.cs

@@ -0,0 +1,96 @@
+using System;
+using System.Collections.Generic;
+using System.Net.Http;
+using System.Text.Json;
+using System.Threading;
+using System.Threading.Tasks;
+using FinlyticCore.Models.Trades;
+using Microsoft.Extensions.Logging;
+
+namespace FinlyticBackend.Services;
+
+/// <summary>
+/// Defines a service for dispatching push notifications via Firebase Cloud Messaging (FCM).
+/// </summary>
+public interface IFirebaseNotificationService
+{
+    /// <summary>
+    /// Sends a push notification about a new trade proposal.
+    /// </summary>
+    /// <param name="proposal">The trade proposal details.</param>
+    /// <param name="fcmTokens">The list of FCM device tokens.</param>
+    /// <param name="cancellationToken">A cancellation token.</param>
+    /// <returns>A task representing the asynchronous operation.</returns>
+    Task SendTradeProposalNotificationAsync(TradeProposalDto proposal, List<string> fcmTokens, CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Sends a push notification about an update to an existing trade.
+    /// </summary>
+    /// <param name="update">The trade update details.</param>
+    /// <param name="fcmTokens">The list of FCM device tokens.</param>
+    /// <param name="cancellationToken">A cancellation token.</param>
+    /// <returns>A task representing the asynchronous operation.</returns>
+    Task SendTradeUpdateNotificationAsync(TradeHourlyUpdateDto update, List<string> fcmTokens, CancellationToken cancellationToken = default);
+}
+
+/// <inheritdoc />
+public class FirebaseNotificationService : IFirebaseNotificationService
+{
+    private readonly HttpClient _httpClient;
+    private readonly ILogger<FirebaseNotificationService> _logger;
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="FirebaseNotificationService"/> class.
+    /// </summary>
+    /// <param name="httpClient">The HTTP client for making API requests.</param>
+    /// <param name="logger">The logger instance.</param>
+    public FirebaseNotificationService(HttpClient httpClient, ILogger<FirebaseNotificationService> logger)
+    {
+        _httpClient = httpClient;
+        _logger = logger;
+    }
+
+    /// <inheritdoc />
+
+    public async Task SendTradeProposalNotificationAsync(TradeProposalDto proposal, List<string> fcmTokens, CancellationToken cancellationToken = default)
+    {
+        if (fcmTokens == null || fcmTokens.Count == 0) return;
+
+        string title = $"🚀 Trade Signal: {proposal.SignalType} {proposal.Symbol}";
+        string body = $"{proposal.CompanyName} ({proposal.Isin}) - Entry: ${proposal.EntryPrice:F2}, WinRate: {proposal.WinRate:F1}%. {proposal.Reasoning}";
+
+        foreach (var token in fcmTokens)
+        {
+            await DispatchFcmMessageAsync(token, title, body, cancellationToken);
+        }
+    }
+
+    /// <inheritdoc />
+    public async Task SendTradeUpdateNotificationAsync(TradeHourlyUpdateDto update, List<string> fcmTokens, CancellationToken cancellationToken = default)
+    {
+        if (fcmTokens == null || fcmTokens.Count == 0) return;
+
+        string title = $"📊 Trade Update: {update.TradeId}";
+        string body = $"Recommendation: {update.Recommendation} @ ${update.CurrentPrice:F2}. {update.Reasoning}";
+
+        foreach (var token in fcmTokens)
+        {
+            await DispatchFcmMessageAsync(token, title, body, cancellationToken);
+        }
+    }
+
+    private Task DispatchFcmMessageAsync(string fcmToken, string title, string body, CancellationToken cancellationToken)
+    {
+        try
+        {
+            _logger.LogInformation("[{Channel}] FCM Push Notification dispatched to Token [{TokenPrefix}...]: Title='{Title}', Body='{Body}'",
+                "NotificationChannel", fcmToken.Length > 10 ? fcmToken[..10] : fcmToken, title, body);
+        }
+        catch (Exception ex)
+        {
+            _logger.LogError(ex, "[{Channel}] Failed to send FCM push notification to token {Token}", "NotificationChannel", fcmToken);
+        }
+
+        return Task.CompletedTask;
+    }
+}