Add AFK tracking system.

Allows us to see which players have not done any input and can be considered AFK.

Content.Server/Afk/AfkManager.cs

@@ -0,0 +1,103 @@
+using System;
+using System.Collections.Generic;
+using Content.Shared.CCVar;
+using JetBrains.Annotations;
+using Robust.Server.Player;
+using Robust.Shared.Configuration;
+using Robust.Shared.Console;
+using Robust.Shared.Enums;
+using Robust.Shared.GameObjects;
+using Robust.Shared.Input;
+using Robust.Shared.IoC;
+using Robust.Shared.Timing;
+
+namespace Content.Server.Afk
+{
+    /// <summary>
+    /// Tracks AFK (away from keyboard) status for players.
+    /// </summary>
+    /// <seealso cref="CCVars.AfkTime"/>
+    public interface IAfkManager
+    {
+        /// <summary>
+        /// Check whether this player is currently AFK.
+        /// </summary>
+        /// <param name="player">The player to check.</param>
+        /// <returns>True if the player is AFK, false otherwise.</returns>
+        bool IsAfk(IPlayerSession player);
+
+        /// <summary>
+        /// Resets AFK status for the player as if they just did an action and are definitely not AFK.
+        /// </summary>
+        /// <param name="player">The player to set AFK status for.</param>
+        void PlayerDidAction(IPlayerSession player);
+
+        void Initialize();
+    }
+
+    [UsedImplicitly]
+    public class AfkManager : IAfkManager, IEntityEventSubscriber
+    {
+        [Dependency] private readonly IEntityManager _entityManager = default!;
+        [Dependency] private readonly IPlayerManager _playerManager = default!;
+        [Dependency] private readonly IGameTiming _gameTiming = default!;
+        [Dependency] private readonly IConfigurationManager _cfg = default!;
+        [Dependency] private readonly IConsoleHost _consoleHost = default!;
+
+        private readonly Dictionary<IPlayerSession, TimeSpan> _lastActionTimes = new();
+
+        public void Initialize()
+        {
+            // Connecting, console commands and input commands all reset AFK status.
+
+            _playerManager.PlayerStatusChanged += PlayerStatusChanged;
+            _consoleHost.AnyCommandExecuted += ConsoleHostOnAnyCommandExecuted;
+
+            _entityManager.EventBus.SubscribeSessionEvent<FullInputCmdMessage>(
+                EventSource.Network,
+                this,
+                HandleInputCmd);
+        }
+
+        public void PlayerDidAction(IPlayerSession player)
+        {
+            if (player.Status == SessionStatus.Disconnected)
+                // Make sure we don't re-add to the dictionary if the player is disconnected now.
+                return;
+
+            _lastActionTimes[player] = _gameTiming.RealTime;
+        }
+
+        public bool IsAfk(IPlayerSession player)
+        {
+            if (!_lastActionTimes.TryGetValue(player, out var time))
+                // Some weird edge case like disconnected clients. Just say true I guess.
+                return true;
+
+            var timeOut = TimeSpan.FromSeconds(_cfg.GetCVar(CCVars.AfkTime));
+            return _gameTiming.RealTime - time > timeOut;
+        }
+
+        private void PlayerStatusChanged(object? sender, SessionStatusEventArgs e)
+        {
+            if (e.NewStatus == SessionStatus.Disconnected)
+            {
+                _lastActionTimes.Remove(e.Session);
+                return;
+            }
+
+            PlayerDidAction(e.Session);
+        }
+
+        private void ConsoleHostOnAnyCommandExecuted(IConsoleShell shell, string commandname, string argstr, string[] args)
+        {
+            if (shell.Player is IPlayerSession player)
+                PlayerDidAction(player);
+        }
+
+        private void HandleInputCmd(FullInputCmdMessage msg, EntitySessionEventArgs args)
+        {
+            PlayerDidAction((IPlayerSession) args.SenderSession);
+        }
+    }
+}

Content.Server/Afk/IsAfkCommand.cs

@@ -0,0 +1,36 @@
+using Content.Server.Administration;
+using Content.Shared.Administration;
+using Robust.Server.Player;
+using Robust.Shared.Console;
+using Robust.Shared.IoC;
+
+namespace Content.Server.Afk
+{
+    [AdminCommand(AdminFlags.Admin)]
+    public sealed class IsAfkCommand : IConsoleCommand
+    {
+        public string Command => "isafk";
+        public string Description => "Checks if a specified player is AFK";
+        public string Help => "Usage: isafk <playerName>";
+
+        public void Execute(IConsoleShell shell, string argStr, string[] args)
+        {
+            var playerManager = IoCManager.Resolve<IPlayerManager>();
+            var afkManager = IoCManager.Resolve<IAfkManager>();
+
+            if (args.Length == 0)
+            {
+                shell.WriteError("Need one argument");
+                return;
+            }
+
+            if (!playerManager.TryGetSessionByUsername(args[0], out var player))
+            {
+                shell.WriteError("Unable to find that player");
+                return;
+            }
+
+            shell.WriteLine(afkManager.IsAfk(player) ? "They are indeed AFK" : "They are not AFK");
+        }
+    }
+}

Content.Server/Entry/EntryPoint.cs

@@ -1,4 +1,5 @@
 using Content.Server.Administration.Managers;
+using Content.Server.Afk;
 using Content.Server.AI.Utility;
 using Content.Server.AI.Utility.Considerations;
 using Content.Server.AI.WorldState;
@@ -92,6 +93,7 @@ namespace Content.Server.Entry
             IoCManager.Resolve<IPDAUplinkManager>().Initialize();
             IoCManager.Resolve<IAdminManager>().Initialize();
             IoCManager.Resolve<INpcBehaviorManager>().Initialize();
+            IoCManager.Resolve<IAfkManager>().Initialize();
             _euiManager.Initialize();
 
             IoCManager.Resolve<IEntitySystemManager>().GetEntitySystem<GameTicker>().PostInitialize();

Content.Server/IoC/ServerContentIoC.cs

@@ -1,5 +1,6 @@
 using Content.Server.Administration;
 using Content.Server.Administration.Managers;
+using Content.Server.Afk;
 using Content.Server.AI.Utility;
 using Content.Server.AI.Utility.Considerations;
 using Content.Server.AI.WorldState;
@@ -62,6 +63,7 @@ namespace Content.Server.IoC
             IoCManager.Register<IVoteManager, VoteManager>();
             IoCManager.Register<INpcBehaviorManager, NpcBehaviorManager>();
             IoCManager.Register<IPlayerLocator, PlayerLocator>();
+            IoCManager.Register<IAfkManager, AfkManager>();
         }
     }
 }

Content.Shared/CCVar/CCVars.cs

@@ -382,5 +382,15 @@ namespace Content.Shared.CCVar
 
         public static readonly CVarDef<int> ChatMaxMessageLength =
             CVarDef.Create("chat.max_message_length", 1000, CVar.SERVER | CVar.REPLICATED);
+
+        /*
+         * AFK
+         */
+
+        /// <summary>
+        /// How long a client can go without any input before being considered AFK.
+        /// </summary>
+        public static readonly CVarDef<float> AfkTime =
+            CVarDef.Create("afk.time", 60f, CVar.SERVERONLY);
     }
 }