add attendance

API/ROLAC.API/Hubs/AttendanceHub.cs

@@ -0,0 +1,39 @@
+using Microsoft.AspNetCore.SignalR;
+using ROLAC.API.Services;
+
+namespace ROLAC.API.Hubs;
+
+/// <summary>
+/// Real-time hub backing the public Sunday attendance counter. Anonymous
+/// (no [Authorize]) so volunteers can use it without logging in. Every
+/// increment is broadcast to all connected clients so multiple people can
+/// count the same Sunday together and see each other's changes instantly.
+/// </summary>
+public class AttendanceHub : Hub
+{
+    private readonly IMealAttendanceService _svc;
+
+    public AttendanceHub(IMealAttendanceService svc) => _svc = svc;
+
+    // Push the current counts to a client the moment it connects.
+    public override async Task OnConnectedAsync()
+    {
+        var counts = await _svc.GetOrCreateAsync(_svc.Today);
+        await Clients.Caller.SendAsync("ReceiveCounts", counts);
+        await base.OnConnectedAsync();
+    }
+
+    // Apply a batched delta for one age group, then broadcast the new totals to everyone.
+    public async Task Increment(string category, int delta)
+    {
+        var counts = await _svc.IncrementAsync(_svc.Today, category, delta);
+        await Clients.All.SendAsync("ReceiveCounts", counts);
+    }
+
+    // Overwrite one age group with an absolute value, then broadcast the new totals to everyone.
+    public async Task SetCount(string category, int value)
+    {
+        var counts = await _svc.SetAsync(_svc.Today, category, value);
+        await Clients.All.SendAsync("ReceiveCounts", counts);
+    }
+}