Adds support for a map rotation system. (#7162)

* Adds support for a map rotation system.
It is now the default way of selecting a map, map votes have been disabled.

* whoops

* Randomize the map it starts off with, too.
(it'd pick bagel every time otherwise)

* Address review

* remove knight from rotation due to it being an unmaintained map.

* minor cleanup

Content.Server/GameTicking/GameTicker.RoundFlow.cs

@@ -71,7 +71,7 @@ namespace Content.Server.GameTicking
             DefaultMap = _mapManager.CreateMap();
             _mapManager.AddUninitializedMap(DefaultMap);
             var startTime = _gameTiming.RealTime;
-            var maps = new List<GameMapPrototype>() { _gameMapManager.GetSelectedMapChecked(true) };
+            var maps = new List<GameMapPrototype>() { _gameMapManager.GetSelectedMapChecked(true, true) };
 
             // Let game rules dictate what maps we should load.
             RaiseLocalEvent(new LoadingMapsEvent(maps));

Content.Server/Maps/GameMapManager.cs

@@ -22,8 +22,11 @@ public sealed class GameMapManager : IGameMapManager
     [Dependency] private readonly IRobustRandom _random = default!;
     [Dependency] private readonly IChatManager _chatManager = default!;
 
+    private readonly Queue<string> _previousMaps = new Queue<string>();
     private GameMapPrototype _currentMap = default!;
     private bool _currentMapForced;
+    private bool _mapRotationEnabled;
+    private int _mapQueueDepth = 1;
 
     public void Initialize()
     {
@@ -35,6 +38,25 @@ public sealed class GameMapManager : IGameMapManager
                 throw new ArgumentException($"Unknown map prototype {value} was selected!");
         }, true);
         _configurationManager.OnValueChanged(CCVars.GameMapForced, value => _currentMapForced = value, true);
+        _configurationManager.OnValueChanged(CCVars.GameMapRotation, value => _mapRotationEnabled = value, true);
+        _configurationManager.OnValueChanged(CCVars.GameMapMemoryDepth, value =>
+        {
+            _mapQueueDepth = value;
+            // Drain excess.
+            while (_previousMaps.Count > _mapQueueDepth)
+            {
+                _previousMaps.Dequeue();
+            }
+        }, true);
+
+        var maps = AllVotableMaps().ToArray();
+        _random.Shuffle(maps);
+        foreach (var map in maps)
+        {
+            if (_previousMaps.Count >= _mapQueueDepth)
+                break;
+            _previousMaps.Enqueue(map.ID);
+        }
     }
 
     public IEnumerable<GameMapPrototype> CurrentlyEligibleMaps()
@@ -75,17 +97,18 @@ public sealed class GameMapManager : IGameMapManager
     public void SelectRandomMap()
     {
         var maps = CurrentlyEligibleMaps().ToList();
-        _random.Shuffle(maps);
-        _currentMap = maps[0];
+        _currentMap = _random.Pick(maps);
         _currentMapForced = false;
     }
 
     public GameMapPrototype GetSelectedMap()
     {
-        return _currentMap;
+        if (!_mapRotationEnabled || _currentMapForced)
+            return _currentMap;
+        return SelectMapInQueue() ?? CurrentlyEligibleMaps().First();
     }
 
-    public GameMapPrototype GetSelectedMapChecked(bool loud = false)
+    public GameMapPrototype GetSelectedMapChecked(bool loud = false, bool markAsPlayed = false)
     {
         if (!_currentMapForced && !IsMapEligible(GetSelectedMap()))
         {
@@ -100,7 +123,11 @@ public sealed class GameMapManager : IGameMapManager
             }
         }
 
-        return GetSelectedMap();
+        var map = GetSelectedMap();
+
+        if (markAsPlayed)
+            _previousMaps.Enqueue(map.ID);
+        return map;
     }
 
     public bool CheckMapExists(string gameMap)
@@ -127,4 +154,39 @@ public sealed class GameMapManager : IGameMapManager
         else
             return gameMap.MapName;
     }
+
+    public int GetMapQueuePriority(string gameMapProtoName)
+    {
+        var i = 0;
+        foreach (var map in _previousMaps.Reverse())
+        {
+            if (map == gameMapProtoName)
+                return i;
+            i++;
+        }
+
+        return _mapQueueDepth;
+    }
+
+    public GameMapPrototype? SelectMapInQueue()
+    {
+        var eligible = CurrentlyEligibleMaps()
+            .Where(x => x.Votable)
+            .Select(x => (proto: x, weight: GetMapQueuePriority(x.ID)))
+            .OrderByDescending(x => x.weight).ToArray();
+        if (eligible.Length is 0)
+            return null;
+
+        var weight = eligible[0].weight;
+        return eligible.Where(x => x.Item2 == weight).OrderBy(x => x.proto.ID).First().proto;
+    }
+
+    private void EnqueueMap(string mapProtoName)
+    {
+        _previousMaps.Enqueue(mapProtoName);
+        while (_previousMaps.Count > _mapQueueDepth)
+        {
+            _previousMaps.Dequeue();
+        }
+    }
 }

Content.Server/Maps/IGameMapManager.cs

@@ -56,7 +56,7 @@ public interface IGameMapManager
     /// Gets the currently selected map, double-checking if it can be used.
     /// </summary>
     /// <returns>selected map</returns>
-    GameMapPrototype GetSelectedMapChecked(bool loud = false);
+    GameMapPrototype GetSelectedMapChecked(bool loud = false, bool markAsPlayed = false);
 
     /// <summary>
     /// Checks if the given map exists

Content.Shared/CCVar/CCVars.cs

@@ -126,6 +126,19 @@ namespace Content.Shared.CCVar
         public static readonly CVarDef<bool>
             GameMapForced = CVarDef.Create("game.mapforced", false, CVar.SERVERONLY);
 
+        /// <summary>
+        /// The depth of the queue used to calculate which map is next in rotation.
+        /// This is how long the game "remembers" that some map was put in play. Default is 16 rounds.
+        /// </summary>
+        public static readonly CVarDef<int>
+            GameMapMemoryDepth = CVarDef.Create("game.map_memory_depth", 16, CVar.SERVERONLY);
+
+        /// <summary>
+        /// Is map rotation enabled?
+        /// </summary>
+        public static readonly CVarDef<bool>
+            GameMapRotation = CVarDef.Create<bool>("game.map_rotation", true, CVar.SERVERONLY);
+
         /// <summary>
         ///     Whether a random position offset will be applied to the station on roundstart.
         /// </summary>
@@ -562,7 +575,7 @@ namespace Content.Shared.CCVar
         ///     See vote.enabled, but specific to map votes
         /// </summary>
         public static readonly CVarDef<bool> VoteMapEnabled =
-            CVarDef.Create("vote.map_enabled", true, CVar.SERVERONLY);
+            CVarDef.Create("vote.map_enabled", false, CVar.SERVERONLY);
 
         /// <summary>
         ///     The required ratio of the server that must agree for a restart round vote to go through.

Resources/Prototypes/Maps/game.yml

@@ -88,6 +88,7 @@
     !type:NanotrasenNameGenerator
     prefixCreator: '14'
   mapPath: /Maps/knightship.yml
+  votable: false
   minPlayers: 0
   maxPlayers: 8
   overflowJobs: []