feat: send Discord notification on tester access validation

* Added INotificationService and NotificationService to send notifications via Discord webhook

* Notifications include tester name, IP, country, city, and timestamp

* Service handles timeouts, HTTP errors, and missing webhook configuration gracefully to avoid breaking the main access validation flow

* Updated ValidateTesterAccessUseCase to trigger notifications without affecting core logic

* Added FakeNotificationService for integration tests so they do not depend on Discord

Author: DevD4v3

src/Extensions/ServiceCollectionExtensions.cs

@@ -19,11 +19,7 @@ public static IServiceCollection AddServices(this IServiceCollection services)
 
         services.AddHttpContextAccessor();
         services.AddScoped<IClientIpProvider, ClientIpProvider>();
-        services
-            .AddHttpClient<IIpGeoLocationService, IpGeoLocationService>(httpClient =>
-            {
-                httpClient.Timeout = TimeSpan.FromSeconds(5);
-            });
+        services.AddHttpClients();
 
         services
             .AddSingleton<CreateTesterValidator>()
@@ -35,4 +31,21 @@ public static IServiceCollection AddServices(this IServiceCollection services)
 
         return services;
     }
+
+    private static IServiceCollection AddHttpClients(this IServiceCollection services)
+    {
+        services
+            .AddHttpClient<IIpGeoLocationService, IpGeoLocationService>(httpClient =>
+            {
+                httpClient.Timeout = TimeSpan.FromSeconds(5);
+            });
+
+        services
+            .AddHttpClient<INotificationService, NotificationService>(httpClient =>
+            {
+                httpClient.Timeout = TimeSpan.FromSeconds(5);
+            });
+
+        return services;
+    }
 }

src/Services/NotificationService.cs

@@ -0,0 +1,72 @@
+using DotEnv.Core;
+
+namespace Playtesters.API.Services;
+
+public interface INotificationService
+{
+    Task SendAsync(NotificationMessage message);
+}
+
+public record NotificationMessage(
+    string TesterName, 
+    string IpAddress, 
+    string Country, 
+    string City,
+    DateTime Timestamp
+);
+
+public class NotificationService : INotificationService
+{
+    private readonly ILogger<NotificationService> _logger;
+    private readonly HttpClient _httpClient;
+    private readonly string _discordWebhookUrl;
+    private record DiscordWebhookPayload(string Content);
+
+    public NotificationService(
+        HttpClient httpClient,
+        ILogger<NotificationService> logger)
+    {
+        var envReader = new EnvReader();
+        if (!envReader.TryGetStringValue("DISCORD_WEBHOOK_URL", out var webhookUrl))
+        {
+            logger.LogError("'DISCORD_WEBHOOK_URL' has not been set as an environment variable");
+        }
+        _discordWebhookUrl = webhookUrl ?? string.Empty;
+        _logger = logger;
+        _httpClient = httpClient;
+    }
+
+    public async Task SendAsync(NotificationMessage message)
+    {
+        if (string.IsNullOrWhiteSpace(_discordWebhookUrl))
+        {
+            _logger.LogError("Discord webhook URL is not configured. Skipping notification for Tester {TesterName}", message.TesterName);
+            return;
+        }
+
+        var content = 
+        $"""
+        🔔 *New validated access*
+        👤 Tester: **{message.TesterName}**
+        🌐 IP: `{message.IpAddress}`
+        🌍 Country: {message.Country}
+        🏙️ City: {message.City}
+        ⏰ {message.Timestamp:yyyy-MM-dd HH:mm:ss}
+        """;
+
+        try
+        {
+            var payload = new DiscordWebhookPayload(content);
+            var response = await _httpClient.PostAsJsonAsync(_discordWebhookUrl, payload);
+            response.EnsureSuccessStatusCode();
+        }
+        catch (Exception ex) when (ex is TaskCanceledException or OperationCanceledException)
+        {
+            _logger.LogError(ex, "DiscordWebhook timed out for Tester {TesterName}", message.TesterName);
+        }
+        catch (HttpRequestException ex)
+        {
+            _logger.LogError(ex, "DiscordWebhook HTTP error for Tester {TesterName}", message.TesterName);
+        }
+    }
+}

src/UseCases/Testers/ValidateAccess.cs

@@ -31,7 +31,8 @@ public class ValidateTesterAccessUseCase(
     AppDbContext dbContext,
     ValidateTesterAccessValidator validator,
     IClientIpProvider clientIpProvider,
-    IIpGeoLocationService ipGeoLocationService)
+    IIpGeoLocationService ipGeoLocationService,
+    INotificationService notificationService)
 {
     public async Task<Result<ValidateTesterAccessResponse>> ExecuteAsync(
         ValidateTesterAccessRequest request)
@@ -59,6 +60,15 @@ public async Task<Result<ValidateTesterAccessResponse>> ExecuteAsync(
         dbContext.Add(accessHistory);
         await dbContext.SaveChangesAsync();
 
+        var notificationMessage = new NotificationMessage(
+            TesterName: tester.Name,
+            IpAddress: ipAddress,
+            Country: location.Country,
+            City: location.City,
+            Timestamp: accessHistory.CheckedAt
+        );
+        await notificationService.SendAsync(notificationMessage);
+
         var response = new ValidateTesterAccessResponse(
             Name: tester.Name,
             TotalHoursPlayed: tester.TotalHoursPlayed,

tests/Common/CustomWebApplicationFactory.cs

@@ -19,10 +19,15 @@ protected override void ConfigureWebHost(IWebHostBuilder builder)
             var ipGeoLocationServiceDescriptor = services.SingleOrDefault(
                 d => d.ServiceType == typeof(IIpGeoLocationService));
 
+            var notificationServiceDescriptor = services.SingleOrDefault(
+                d => d.ServiceType == typeof(INotificationService));
+
             services.Remove(clientIpProviderDescriptor);
             services.Remove(ipGeoLocationServiceDescriptor);
+            services.Remove(notificationServiceDescriptor);
             services.AddSingleton<IClientIpProvider, FakeClientIpProvider>();
             services.AddSingleton<IIpGeoLocationService, FakeIpGeoLocationService>();
+            services.AddSingleton<INotificationService, FakeNotificationService>();
         });
     }
 }

tests/Common/FakeNotificationService.cs

@@ -0,0 +1,8 @@
+using Playtesters.API.Services;
+
+namespace Playtesters.API.Tests.Common;
+
+public class FakeNotificationService : INotificationService
+{
+    public Task SendAsync(NotificationMessage message) => Task.CompletedTask;
+}