Add info api for #231

WebfrontCore/Controllers/API/Dtos/InfoResponse.cs

@@ -0,0 +1,21 @@
+using System;
+
+namespace WebfrontCore.Controllers.API.Dtos;
+
+public class InfoResponse
+{
+    public int TotalConnectedClients { get; set; }
+    public int TotalClientSlots { get; set; }
+    public int TotalTrackedClients { get; set; }
+    public MetricSnapshot<int> TotalRecentClients { get; set; }
+
+    public MetricSnapshot<int?> MaxConcurrentClients { get; set; }
+}
+
+public class MetricSnapshot<T>
+{
+    public T Value { get; set; }
+    public DateTime? Time { get; set; }
+    public DateTime? StartAt { get; set; }
+    public DateTime? EndAt { get; set; }
+}

WebfrontCore/Controllers/API/Info.cs

@@ -0,0 +1,53 @@
+using System;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Mvc;
+using SharedLibraryCore;
+using SharedLibraryCore.Interfaces;
+using WebfrontCore.Controllers.API.Dtos;
+
+namespace WebfrontCore.Controllers.API;
+
+[ApiController]
+[Route("api/[controller]")]
+public class Info : BaseController
+{
+    private readonly IServerDataViewer _serverDataViewer;
+    
+    public Info(IManager manager, IServerDataViewer serverDataViewer) : base(manager)
+    {
+        _serverDataViewer = serverDataViewer;
+    }
+    
+    [HttpGet]
+    public async Task<IActionResult> Get(int period = 24, CancellationToken token = default)
+    {
+        // todo: this is hardcoded currently because the cache doesn't take into consideration the duration, so 
+        // we could impact the webfront usage too
+        var duration = TimeSpan.FromHours(24);
+        var (totalClients, totalRecentClients) =
+            await _serverDataViewer.ClientCountsAsync(duration, token);
+        var (maxConcurrent, maxConcurrentTime) = await _serverDataViewer.MaxConcurrentClientsAsync(overPeriod: duration, token: token);
+        var response = new InfoResponse
+        {
+            TotalTrackedClients = totalClients,
+            TotalConnectedClients = Manager.GetActiveClients().Count,
+            TotalClientSlots = Manager.GetServers().Sum(server => server.MaxClients),
+            MaxConcurrentClients = new MetricSnapshot<int?>
+            {
+                Value = maxConcurrent, Time = maxConcurrentTime, 
+                EndAt = DateTime.UtcNow,
+                StartAt = DateTime.UtcNow - duration
+            },
+            TotalRecentClients = new MetricSnapshot<int>
+            {
+                Value = totalRecentClients,
+                EndAt = DateTime.UtcNow,
+                StartAt = DateTime.UtcNow - duration
+            }
+        };
+
+        return Json(response);
+    }
+}