Implement telemetry system with data collection and reporting

Signed-off-by: Dmitrii <computer@yawaflua.tech>

Took 20 minutes

backend/SpMega.Backend/Controllers/v1/AuthController.cs

@@ -20,6 +20,7 @@ namespace SpMega.Backend.Controllers.v1;
 
 public record GetSessionIdBody(string userName, Guid userUUID);
 public record ValidateSessionBody(string sessionId, Guid userUUID);
+
 [Route("api/v1/auth")]
 [ApiController]
 public class AuthController(AppDbContext dbContext, TokenService tokenService, ILogger<AuthController> logger) : ControllerBase
@@ -67,7 +68,7 @@ public class AuthController(AppDbContext dbContext, TokenService tokenService, I
 
             var resp = await httpClient.SendAsync(request);
             if (resp.StatusCode != HttpStatusCode.OK) throw new Exception("Mojang response is not OK");
-            Console.WriteLine(await resp.Content.ReadAsStringAsync());
+            
             var dto = await resp.Content.ReadFromJsonAsync<MojangDto>();
             if (dto == null || dto.Name != session.UserName || Guid.Parse(dto.Id) != session.UserId) throw new Exception("Session expired, or dto is not acceptable.");
             var token = tokenService.GenerateAccessToken(session.UserName, body.userUUID);
@@ -75,6 +76,9 @@ public class AuthController(AppDbContext dbContext, TokenService tokenService, I
             if (user != null)
             {
                 user.Token = token;
+                user.Username = session.UserName;
+                user.UpdatedAt = DateTime.UtcNow;
+                
                 dbContext.Update(user);
             }
             else
@@ -84,6 +88,7 @@ public class AuthController(AppDbContext dbContext, TokenService tokenService, I
                     Id = body.userUUID,
                     Username = session.UserName,
                     Token = token,
+                    UpdatedAt = DateTime.UtcNow
                 };
                 await dbContext.AddAsync(user);
             }

backend/SpMega.Backend/Controllers/v1/TelemetryController.cs

@@ -0,0 +1,45 @@
+using System.Diagnostics;
+using System.Text.Json;
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using SpMega.Backend.Persistent.Models.DTO;
+using SpMega.Backend.Persistent.Models.Users;
+
+namespace SpMega.Backend.Controllers.v1;
+
+[ApiController]
+[Route("api/v1/telemetry")]
+public class TelemetryController : ControllerBase
+{
+    private static readonly ActivitySource Source = new("SpMega.ModTelemetry");
+
+    [HttpPost]
+    [Authorize]
+    public IActionResult Post([FromBody] ModTelemetryBatchDto batch)
+    {
+        if (batch?.Events == null || batch.Events.Count == 0)
+        {
+            return Ok(new { received = 0 });
+        }
+
+        var user = HttpContext.Items["@me"] as User;
+        var userId = user?.Id.ToString() ?? User.FindFirst(System.Security.Claims.ClaimTypes.NameIdentifier)?.Value ?? "anonymous";
+        var sessionId = !string.IsNullOrEmpty(batch.SessionId) ? batch.SessionId : Guid.NewGuid().ToString("N");
+
+        foreach (var e in batch.Events)
+        {
+            using var activity = Source.StartActivity("mod.telemetry.event", ActivityKind.Internal);
+            if (activity is null) continue;
+
+            activity.SetTag("user.id", userId);
+            activity.SetTag("session.id", sessionId);
+            activity.SetTag("client.version", batch.ClientVersion ?? string.Empty);
+            activity.SetTag("event.type", e.EventType);
+            activity.SetTag("event.timestamp", e.Timestamp.ToString("O"));
+            activity.SetTag("event.payload", JsonSerializer.Serialize(e.Payload));
+            activity.SetTag("batch.sent_at", batch.SentAt.ToString("O"));
+        }
+
+        return Ok(new { received = batch.Events.Count });
+    }
+}