add alert/notification functionality (for server connection events and messages)

Application/Alerts/AlertManager.cs

@@ -0,0 +1,137 @@
+using System;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using SharedLibraryCore.Alerts;
+using SharedLibraryCore.Configuration;
+using SharedLibraryCore.Database.Models;
+using SharedLibraryCore.Interfaces;
+
+namespace IW4MAdmin.Application.Alerts;
+
+public class AlertManager : IAlertManager
+{
+    private readonly ApplicationConfiguration _appConfig;
+    private readonly ConcurrentDictionary<int, List<Alert.AlertState>> _states = new();
+    private readonly List<Func<Task<IEnumerable<Alert.AlertState>>>> _staticSources = new();
+
+    public AlertManager(ApplicationConfiguration appConfig)
+    {
+        _appConfig = appConfig;
+        _states.TryAdd(0, new List<Alert.AlertState>());
+    }
+
+    public EventHandler<Alert.AlertState> OnAlertConsumed { get; set; }
+
+    public async Task Initialize()
+    {
+        foreach (var source in _staticSources)
+        {
+            var alerts = await source();
+            foreach (var alert in alerts)
+            {
+                AddAlert(alert);
+            }
+        }
+    }
+
+    public IEnumerable<Alert.AlertState> RetrieveAlerts(EFClient client)
+    {
+        lock (_states)
+        {
+            var alerts = Enumerable.Empty<Alert.AlertState>();
+            if (client.Level > Data.Models.Client.EFClient.Permission.Trusted)
+            {
+                alerts = alerts.Concat(_states[0].Where(alert =>
+                    alert.MinimumPermission is null || alert.MinimumPermission <= client.Level));
+            }
+
+            if (_states.ContainsKey(client.ClientId))
+            {
+                alerts = alerts.Concat(_states[client.ClientId].AsReadOnly());
+            }
+
+            return alerts.OrderByDescending(alert => alert.OccuredAt);
+        }
+    }
+
+    public void MarkAlertAsRead(Guid alertId)
+    {
+        lock (_states)
+        {
+            foreach (var items in _states.Values)
+            {
+                var matchingEvent = items.FirstOrDefault(item => item.AlertId == alertId);
+
+                if (matchingEvent is null)
+                {
+                    continue;
+                }
+
+                items.Remove(matchingEvent);
+                OnAlertConsumed?.Invoke(this, matchingEvent);
+            }
+        }
+    }
+
+    public void MarkAllAlertsAsRead(int recipientId)
+    {
+        lock (_states)
+        {
+            foreach (var items in _states.Values)
+            {
+                items.RemoveAll(item =>
+                {
+                    if (item.RecipientId != null && item.RecipientId != recipientId)
+                    {
+                        return false;
+                    }
+
+                    OnAlertConsumed?.Invoke(this, item);
+                    return true;
+                });
+            }
+        }
+    }
+
+    public void AddAlert(Alert.AlertState alert)
+    {
+        lock (_states)
+        {
+            if (alert.RecipientId is null)
+            {
+                _states[0].Add(alert);
+                return;
+            }
+
+            if (!_states.ContainsKey(alert.RecipientId.Value))
+            {
+                _states[alert.RecipientId.Value] = new List<Alert.AlertState>();
+            }
+
+            if (_appConfig.MinimumAlertPermissions.ContainsKey(alert.Type))
+            {
+                alert.MinimumPermission = _appConfig.MinimumAlertPermissions[alert.Type];
+            }
+
+            _states[alert.RecipientId.Value].Add(alert);
+
+            PruneOldAlerts();
+        }
+    }
+
+    public void RegisterStaticAlertSource(Func<Task<IEnumerable<Alert.AlertState>>> alertSource)
+    {
+        _staticSources.Add(alertSource);
+    }
+
+
+    private void PruneOldAlerts()
+    {
+        foreach (var value in _states.Values)
+        {
+            value.RemoveAll(item => item.ExpiresAt < DateTime.UtcNow);
+        }
+    }
+}