Roundstart variation game rules (#24397)

* Raise `StationPostInitEvent` broadcast

* Basic variation pass handling

* standardize names + rule entities

* why does it work like that?

* add to defaults

* light break variation pass

* ent spawn entry

* move some stationevent utility functions to gamerule + add one for finding random tile on specified station

* forgot how statistics works

* powered light variation pass is good now

* station tile count function

* public method to ensure all solutions (for procedural use before mapinit)

* move gamerulesystem utility funcs to partial

* ensure all solutions before spilling in puddlesystem. for use when spilling before mapinit

* trash & puddle variation passes!

* oh yeah

* ehh lets live a little

* std

* utility for game rule check based on comp

* entprotoid the trash spawner oops

* generalize trash variation

* use added instead of started for secret rule

* random cleanup

* generic replacement variation system

* Wall rusting variation rule

* account for modifying while enumerating

* use localaabb

* fix test

* minor tweaks

* reinforced wall replacer + puddletweaker

(cherry picked from commit cc24ba6a317c4bee84ffa1eda8397c255ca92be9)

Content.Server/GameTicking/GameTicker.GamePreset.cs

@@ -188,7 +188,7 @@ namespace Content.Server.GameTicking
             return true;
         }
 
-        private void StartGamePresetRules()
+        public void StartGamePresetRules()
         {
             // May be touched by the preset during init.
             var rules = new List<EntityUid>(GetAddedGameRules());

Content.Server/GameTicking/GameTicker.GameRule.cs

@@ -141,6 +141,24 @@ public sealed partial class GameTicker
         return true;
     }
 
+    /// <summary>
+    ///     Returns true if a game rule with the given component has been added.
+    /// </summary>
+    public bool IsGameRuleAdded<T>()
+        where T : IComponent
+    {
+        var query = EntityQueryEnumerator<T, GameRuleComponent>();
+        while (query.MoveNext(out var uid, out _, out _))
+        {
+            if (HasComp<EndedGameRuleComponent>(uid))
+                continue;
+
+            return true;
+        }
+
+        return false;
+    }
+
     public bool IsGameRuleAdded(EntityUid ruleEntity, GameRuleComponent? component = null)
     {
         return Resolve(ruleEntity, ref component) && !HasComp<EndedGameRuleComponent>(ruleEntity);
@@ -157,6 +175,22 @@ public sealed partial class GameTicker
         return false;
     }
 
+    /// <summary>
+    ///     Returns true if a game rule with the given component is active..
+    /// </summary>
+    public bool IsGameRuleActive<T>()
+        where T : IComponent
+    {
+        var query = EntityQueryEnumerator<T, ActiveGameRuleComponent, GameRuleComponent>();
+        // out, damned underscore!!!
+        while (query.MoveNext(out _, out _, out _, out _))
+        {
+            return true;
+        }
+
+        return false;
+    }
+
     public bool IsGameRuleActive(EntityUid ruleEntity, GameRuleComponent? component = null)
     {
         return Resolve(ruleEntity, ref component) && HasComp<ActiveGameRuleComponent>(ruleEntity);

Content.Server/GameTicking/Rules/Components/RoundstartStationVariationRuleComponent.cs

@@ -0,0 +1,19 @@
+using Content.Shared.Storage;
+using Robust.Shared.Prototypes;
+
+namespace Content.Server.GameTicking.Rules.Components;
+
+/// <summary>
+/// This handles starting various roundstart variation rules after a station has been loaded.
+/// </summary>
+[RegisterComponent]
+public sealed partial class RoundstartStationVariationRuleComponent : Component
+{
+    /// <summary>
+    ///     The list of rules that will be started once the map is spawned.
+    ///     Uses <see cref="EntitySpawnEntry"/> to support probabilities for various rules
+    ///     without having to hardcode the probability directly in the rule's logic.
+    /// </summary>
+    [DataField(required: true)]
+    public List<EntitySpawnEntry> Rules = new();
+}

Content.Server/GameTicking/Rules/Components/StationVariationPassRuleComponent.cs

@@ -0,0 +1,9 @@
+namespace Content.Server.GameTicking.Rules.Components;
+
+/// <summary>
+/// This is a marker component placed on rule entities which are a single "pass" of station variation.
+/// </summary>
+[RegisterComponent]
+public sealed partial class StationVariationPassRuleComponent : Component
+{
+}

Content.Server/GameTicking/Rules/GameRuleSystem.Utility.cs

@@ -0,0 +1,137 @@
+using System.Diagnostics.CodeAnalysis;
+using Content.Server.GameTicking.Rules.Components;
+using Content.Server.Station.Components;
+using Robust.Shared.Collections;
+using Robust.Shared.Map;
+using Robust.Shared.Map.Components;
+using Robust.Shared.Random;
+
+namespace Content.Server.GameTicking.Rules;
+
+public abstract partial class GameRuleSystem<T> where T: IComponent
+{
+    protected EntityQueryEnumerator<ActiveGameRuleComponent, T, GameRuleComponent> QueryActiveRules()
+    {
+        return EntityQueryEnumerator<ActiveGameRuleComponent, T, GameRuleComponent>();
+    }
+
+    protected bool TryRoundStartAttempt(RoundStartAttemptEvent ev, string localizedPresetName)
+    {
+        var query = EntityQueryEnumerator<ActiveGameRuleComponent, T, GameRuleComponent>();
+        while (query.MoveNext(out _, out _, out _, out var gameRule))
+        {
+            var minPlayers = gameRule.MinPlayers;
+            if (!ev.Forced && ev.Players.Length < minPlayers)
+            {
+                ChatManager.SendAdminAnnouncement(Loc.GetString("preset-not-enough-ready-players",
+                    ("readyPlayersCount", ev.Players.Length), ("minimumPlayers", minPlayers),
+                    ("presetName", localizedPresetName)));
+                ev.Cancel();
+                continue;
+            }
+
+            if (ev.Players.Length == 0)
+            {
+                ChatManager.DispatchServerAnnouncement(Loc.GetString("preset-no-one-ready"));
+                ev.Cancel();
+            }
+        }
+
+        return !ev.Cancelled;
+    }
+
+    /// <summary>
+    ///     Utility function for finding a random event-eligible station entity
+    /// </summary>
+    protected bool TryGetRandomStation([NotNullWhen(true)] out EntityUid? station, Func<EntityUid, bool>? filter = null)
+    {
+        var stations = new ValueList<EntityUid>(Count<StationEventEligibleComponent>());
+
+        filter ??= _ => true;
+        var query = AllEntityQuery<StationEventEligibleComponent>();
+
+        while (query.MoveNext(out var uid, out _))
+        {
+            if (!filter(uid))
+                continue;
+
+            stations.Add(uid);
+        }
+
+        if (stations.Count == 0)
+        {
+            station = null;
+            return false;
+        }
+
+        // TODO: Engine PR.
+        station = stations[RobustRandom.Next(stations.Count)];
+        return true;
+    }
+
+    protected bool TryFindRandomTile(out Vector2i tile,
+        [NotNullWhen(true)] out EntityUid? targetStation,
+        out EntityUid targetGrid,
+        out EntityCoordinates targetCoords)
+    {
+        tile = default;
+        targetStation = EntityUid.Invalid;
+        targetGrid = EntityUid.Invalid;
+        targetCoords = EntityCoordinates.Invalid;
+        if (TryGetRandomStation(out targetStation))
+        {
+            return TryFindRandomTileOnStation((targetStation.Value, Comp<StationDataComponent>(targetStation.Value)),
+                out tile,
+                out targetGrid,
+                out targetCoords);
+        }
+
+        return false;
+    }
+
+    protected bool TryFindRandomTileOnStation(Entity<StationDataComponent> station,
+        out Vector2i tile,
+        out EntityUid targetGrid,
+        out EntityCoordinates targetCoords)
+    {
+        tile = default;
+        targetCoords = EntityCoordinates.Invalid;
+        targetGrid = EntityUid.Invalid;
+
+        var possibleTargets = station.Comp.Grids;
+        if (possibleTargets.Count == 0)
+        {
+            targetGrid = EntityUid.Invalid;
+            return false;
+        }
+
+        targetGrid = RobustRandom.Pick(possibleTargets);
+
+        if (!TryComp<MapGridComponent>(targetGrid, out var gridComp))
+            return false;
+
+        var found = false;
+        var aabb = gridComp.LocalAABB;
+
+        for (var i = 0; i < 10; i++)
+        {
+            var randomX = RobustRandom.Next((int) aabb.Left, (int) aabb.Right);
+            var randomY = RobustRandom.Next((int) aabb.Bottom, (int) aabb.Top);
+
+            tile = new Vector2i(randomX, randomY);
+            if (_atmosphere.IsTileSpace(targetGrid, Transform(targetGrid).MapUid, tile,
+                    mapGridComp: gridComp)
+                || _atmosphere.IsTileAirBlocked(targetGrid, tile, mapGridComp: gridComp))
+            {
+                continue;
+            }
+
+            found = true;
+            targetCoords = _map.GridTileToLocal(targetGrid, gridComp, tile);
+            break;
+        }
+
+        return found;
+    }
+
+}

Content.Server/GameTicking/Rules/GameRuleSystem.cs

@@ -1,13 +1,27 @@
+using System.Diagnostics.CodeAnalysis;
+using Content.Server.Atmos.EntitySystems;
 using Content.Server.Chat.Managers;
 using Content.Server.GameTicking.Rules.Components;
+using Content.Server.Station.Components;
+using Robust.Server.GameObjects;
+using Robust.Shared.Collections;
+using Robust.Shared.Map;
+using Robust.Shared.Map.Components;
+using Robust.Shared.Random;
 
 namespace Content.Server.GameTicking.Rules;
 
 public abstract partial class GameRuleSystem<T> : EntitySystem where T : IComponent
 {
+    [Dependency] protected readonly IRobustRandom RobustRandom = default!;
     [Dependency] protected readonly IChatManager ChatManager = default!;
     [Dependency] protected readonly GameTicker GameTicker = default!;
 
+    // Not protected, just to be used in utility methods
+    [Dependency] private readonly SharedTransformSystem _transform = default!;
+    [Dependency] private readonly AtmosphereSystem _atmosphere = default!;
+    [Dependency] private readonly MapSystem _map = default!;
+
     public override void Initialize()
     {
         base.Initialize();
@@ -71,36 +85,6 @@ public abstract partial class GameRuleSystem<T> : EntitySystem where T : ICompon
 
     }
 
-    protected EntityQueryEnumerator<ActiveGameRuleComponent, T, GameRuleComponent> QueryActiveRules()
-    {
-        return EntityQueryEnumerator<ActiveGameRuleComponent, T, GameRuleComponent>();
-    }
-
-    protected bool TryRoundStartAttempt(RoundStartAttemptEvent ev, string localizedPresetName)
-    {
-        var query = EntityQueryEnumerator<ActiveGameRuleComponent, T, GameRuleComponent>();
-        while (query.MoveNext(out _, out _, out _, out var gameRule))
-        {
-            var minPlayers = gameRule.MinPlayers;
-            if (!ev.Forced && ev.Players.Length < minPlayers)
-            {
-                ChatManager.SendAdminAnnouncement(Loc.GetString("preset-not-enough-ready-players",
-                    ("readyPlayersCount", ev.Players.Length), ("minimumPlayers", minPlayers),
-                    ("presetName", localizedPresetName)));
-                ev.Cancel();
-                continue;
-            }
-
-            if (ev.Players.Length == 0)
-            {
-                ChatManager.DispatchServerAnnouncement(Loc.GetString("preset-no-one-ready"));
-                ev.Cancel();
-            }
-        }
-
-        return !ev.Cancelled;
-    }
-
     public override void Update(float frameTime)
     {
         base.Update(frameTime);

Content.Server/GameTicking/Rules/RoundstartStationVariationRuleSystem.cs

@@ -0,0 +1,70 @@
+using System.Linq;
+using Content.Server.GameTicking.Rules.Components;
+using Content.Server.Shuttles.Systems;
+using Content.Server.Station.Components;
+using Content.Server.Station.Events;
+using Content.Shared.Storage;
+using Robust.Shared.Prototypes;
+using Robust.Shared.Random;
+
+namespace Content.Server.GameTicking.Rules;
+
+/// <inheritdoc cref="RoundstartStationVariationRuleComponent"/>
+public sealed class RoundstartStationVariationRuleSystem : GameRuleSystem<RoundstartStationVariationRuleComponent>
+{
+    [Dependency] private readonly IRobustRandom _random = default!;
+
+    public override void Initialize()
+    {
+        base.Initialize();
+
+        SubscribeLocalEvent<StationPostInitEvent>(OnStationPostInit, after: new []{typeof(ShuttleSystem)});
+    }
+
+    protected override void Added(EntityUid uid, RoundstartStationVariationRuleComponent component, GameRuleComponent gameRule, GameRuleAddedEvent args)
+    {
+        var spawns = EntitySpawnCollection.GetSpawns(component.Rules, _random);
+        foreach (var rule in spawns)
+        {
+            GameTicker.AddGameRule(rule);
+        }
+    }
+
+    private void OnStationPostInit(ref StationPostInitEvent ev)
+    {
+        // as long as one is running
+        if (!GameTicker.IsGameRuleAdded<RoundstartStationVariationRuleComponent>())
+            return;
+
+        // this is unlikely, but could theoretically happen if it was saved and reloaded, so check anyway
+        if (HasComp<StationVariationHasRunComponent>(ev.Station))
+            return;
+
+        Log.Info($"Running variation rules for station {ToPrettyString(ev.Station)}");
+
+        // raise the event on any passes that have been added
+        var passEv = new StationVariationPassEvent(ev.Station);
+        var passQuery = EntityQueryEnumerator<StationVariationPassRuleComponent, GameRuleComponent>();
+        while (passQuery.MoveNext(out var uid, out _, out _))
+        {
+            // TODO: for some reason, ending a game rule just gives it a marker comp,
+            // and doesnt delete it
+            // so we have to check here that it isnt an ended game rule (which could happen if a preset failed to start
+            // or it was ended before station maps spawned etc etc etc)
+            if (HasComp<EndedGameRuleComponent>(uid))
+                continue;
+
+            RaiseLocalEvent(uid, ref passEv);
+        }
+
+        EnsureComp<StationVariationHasRunComponent>(ev.Station);
+    }
+}
+
+/// <summary>
+///     Raised directed on game rule entities which are added and marked as <see cref="StationVariationPassRuleComponent"/>
+///     when a new station is initialized that should be varied.
+/// </summary>
+/// <param name="Station">The new station that was added, and its config & grids.</param>
+[ByRefEvent]
+public readonly record struct StationVariationPassEvent(Entity<StationDataComponent> Station);

Content.Server/GameTicking/Rules/SecretRuleSystem.cs

@@ -18,9 +18,9 @@ public sealed class SecretRuleSystem : GameRuleSystem<SecretRuleComponent>
     [Dependency] private readonly IConfigurationManager _configurationManager = default!;
     [Dependency] private readonly IAdminLogManager _adminLogger = default!;
 
-    protected override void Started(EntityUid uid, SecretRuleComponent component, GameRuleComponent gameRule, GameRuleStartedEvent args)
+    protected override void Added(EntityUid uid, SecretRuleComponent component, GameRuleComponent gameRule, GameRuleAddedEvent args)
     {
-        base.Started(uid, component, gameRule, args);
+        base.Added(uid, component, gameRule, args);
         PickRule(component);
     }
 
@@ -40,13 +40,24 @@ public sealed class SecretRuleSystem : GameRuleSystem<SecretRuleComponent>
         // but currently there's no way to know anyway as they use cvars.
         var presetString = _configurationManager.GetCVar(CCVars.SecretWeightPrototype);
         var preset = _prototypeManager.Index<WeightedRandomPrototype>(presetString).Pick(_random);
-        Logger.InfoS("gamepreset", $"Selected {preset} for secret.");
+        Log.Info($"Selected {preset} for secret.");
         _adminLogger.Add(LogType.EventStarted, $"Selected {preset} for secret.");
 
         var rules = _prototypeManager.Index<GamePresetPrototype>(preset).Rules;
         foreach (var rule in rules)
         {
-            GameTicker.StartGameRule(rule, out var ruleEnt);
+            EntityUid ruleEnt;
+
+            // if we're pre-round (i.e. will only be added)
+            // then just add rules. if we're added in the middle of the round (or at any other point really)
+            // then we want to start them as well
+            if (GameTicker.RunLevel <= GameRunLevel.InRound)
+                ruleEnt = GameTicker.AddGameRule(rule);
+            else
+            {
+                GameTicker.StartGameRule(rule, out ruleEnt);
+            }
+
             component.AdditionalGameRules.Add(ruleEnt);
         }
     }

Content.Server/GameTicking/Rules/VariationPass/BaseEntityReplaceVariationPassSystem.cs

@@ -0,0 +1,75 @@
+using Content.Server.GameTicking.Rules.VariationPass.Components;
+using Content.Shared.Storage;
+using Robust.Shared.Map;
+using Robust.Shared.Random;
+using Robust.Shared.Timing;
+
+namespace Content.Server.GameTicking.Rules.VariationPass;
+
+/// <inheritdoc cref="EntityReplaceVariationPassComponent"/>
+/// <summary>
+///     A base system for fast replacement of entities utilizing a query, rather than having to iterate every entity
+///     To use, you must have a marker component to use for <see cref="TEntComp"/>--each replaceable entity must have it
+///     Then you need an inheriting system as well as a unique game rule component for <see cref="TGameRuleComp"/>
+///
+///     This means a bit more boilerplate for each one, but significantly faster to actually execute.
+///     See <see cref="WallReplaceVariationPassSystem"/>
+/// </summary>
+public abstract class BaseEntityReplaceVariationPassSystem<TEntComp, TGameRuleComp> : VariationPassSystem<TGameRuleComp>
+    where TEntComp: IComponent
+    where TGameRuleComp: IComponent
+{
+    /// <summary>
+    ///     Used so we don't modify while enumerating
+    ///     if the replaced entity also has <see cref="TEntComp"/>.
+    ///
+    ///     Filled and cleared within the same tick so no persistence issues.
+    /// </summary>
+    private readonly Queue<(string, EntityCoordinates, Angle)> _queuedSpawns = new();
+
+    protected override void ApplyVariation(Entity<TGameRuleComp> ent, ref StationVariationPassEvent args)
+    {
+        if (!TryComp<EntityReplaceVariationPassComponent>(ent, out var pass))
+            return;
+
+        var stopwatch = new Stopwatch();
+        stopwatch.Start();
+
+        var replacementMod = Random.NextGaussian(pass.EntitiesPerReplacementAverage, pass.EntitiesPerReplacementStdDev);
+        var prob = (float) Math.Clamp(1 / replacementMod, 0f, 1f);
+
+        if (prob == 0)
+            return;
+
+        var enumerator = AllEntityQuery<TEntComp, TransformComponent>();
+        while (enumerator.MoveNext(out var uid, out _, out var xform))
+        {
+            if (!IsMemberOfStation((uid, xform), ref args))
+                continue;
+
+            if (RobustRandom.Prob(prob))
+                QueueReplace((uid, xform), pass.Replacements);
+        }
+
+        while (_queuedSpawns.TryDequeue(out var tup))
+        {
+            var (spawn, coords, rot) = tup;
+            var newEnt = Spawn(spawn, coords);
+            Transform(newEnt).LocalRotation = rot;
+        }
+
+        Log.Debug($"Entity replacement took {stopwatch.Elapsed} with {Stations.GetTileCount(args.Station)} tiles");
+    }
+
+    private void QueueReplace(Entity<TransformComponent> ent, List<EntitySpawnEntry> replacements)
+    {
+        var coords = ent.Comp.Coordinates;
+        var rot = ent.Comp.LocalRotation;
+        QueueDel(ent);
+
+        foreach (var spawn in EntitySpawnCollection.GetSpawns(replacements, RobustRandom))
+        {
+            _queuedSpawns.Enqueue((spawn, coords, rot));
+        }
+    }
+}

Content.Server/GameTicking/Rules/VariationPass/Components/EntityReplaceVariationPassComponent.cs

@@ -0,0 +1,33 @@
+using Content.Shared.Storage;
+using Content.Shared.Whitelist;
+using Robust.Shared.Prototypes;
+
+namespace Content.Server.GameTicking.Rules.VariationPass.Components;
+
+/// <summary>
+/// This is used for replacing a certain amount of entities with other entities in a variation pass.
+///
+/// </summary>
+/// <remarks>
+/// POTENTIALLY REPLACEABLE ENTITIES MUST BE MARKED WITH A REPLACEMENT MARKER
+/// AND HAVE A SYSTEM INHERITING FROM <see cref="BaseEntityReplaceVariationPassSystem{TEntComp,TGameRuleComp}"/>
+/// SEE <see cref="WallReplaceVariationPassSystem"/>
+/// </remarks>
+[RegisterComponent]
+public sealed partial class EntityReplaceVariationPassComponent : Component
+{
+    /// <summary>
+    ///     Number of matching entities before one will be replaced on average.
+    /// </summary>
+    [DataField(required: true)]
+    public float EntitiesPerReplacementAverage;
+
+    [DataField(required: true)]
+    public float EntitiesPerReplacementStdDev;
+
+    /// <summary>
+    ///     Prototype(s) to replace matched entities with.
+    /// </summary>
+    [DataField(required: true)]
+    public List<EntitySpawnEntry> Replacements = default!;
+}

Content.Server/GameTicking/Rules/VariationPass/Components/EntitySpawnVariationPassComponent.cs

@@ -0,0 +1,27 @@
+using Content.Shared.Random;
+using Content.Shared.Storage;
+using Robust.Shared.Prototypes;
+
+namespace Content.Server.GameTicking.Rules.VariationPass.Components;
+
+/// <summary>
+/// This is used for spawning entities randomly dotted around the station in a variation pass.
+/// </summary>
+[RegisterComponent]
+public sealed partial class EntitySpawnVariationPassComponent : Component
+{
+    /// <summary>
+    ///     Number of tiles before we spawn one entity on average.
+    /// </summary>
+    [DataField]
+    public float TilesPerEntityAverage = 50f;
+
+    [DataField]
+    public float TilesPerEntityStdDev = 7f;
+
+    /// <summary>
+    ///     Spawn entries for each chosen location.
+    /// </summary>
+    [DataField(required: true)]
+    public List<EntitySpawnEntry> Entities = default!;
+}

Content.Server/GameTicking/Rules/VariationPass/Components/PoweredLightVariationPassComponent.cs

@@ -0,0 +1,38 @@
+using Content.Shared.Light.Components;
+using Robust.Shared.Prototypes;
+
+namespace Content.Server.GameTicking.Rules.VariationPass.Components;
+
+/// <summary>
+/// This handle randomly destroying lights, causing them to flicker endlessly, or replacing their tube/bulb with different variants.
+/// </summary>
+[RegisterComponent]
+public sealed partial class PoweredLightVariationPassComponent : Component
+{
+    /// <summary>
+    ///     Chance that a light will be replaced with a broken variant.
+    /// </summary>
+    [DataField]
+    public float LightBreakChance = 0.15f;
+
+    /// <summary>
+    ///     Chance that a light will be replaced with an aged variant.
+    /// </summary>
+    [DataField]
+    public float LightAgingChance = 0.05f;
+
+    [DataField]
+    public float AgedLightTubeFlickerChance = 0.03f;
+
+    [DataField]
+    public EntProtoId BrokenLightBulbPrototype = "LightBulbBroken";
+
+    [DataField]
+    public EntProtoId BrokenLightTubePrototype = "LightTubeBroken";
+
+    [DataField]
+    public EntProtoId AgedLightBulbPrototype = "LightBulbOld";
+
+    [DataField]
+    public EntProtoId AgedLightTubePrototype = "LightTubeOld";
+}

Content.Server/GameTicking/Rules/VariationPass/Components/PuddleMessVariationPassComponent.cs

@@ -0,0 +1,26 @@
+using Content.Shared.Random;
+using Robust.Shared.Prototypes;
+
+namespace Content.Server.GameTicking.Rules.VariationPass.Components;
+
+/// <summary>
+///     Handles spilling puddles with various reagents randomly around the station.
+/// </summary>
+[RegisterComponent]
+public sealed partial class PuddleMessVariationPassComponent : Component
+{
+    /// <summary>
+    ///     Tiles before one spill on average.
+    /// </summary>
+    [DataField]
+    public float TilesPerSpillAverage = 600f;
+
+    [DataField]
+    public float TilesPerSpillStdDev = 50f;
+
+    /// <summary>
+    ///     Weighted random prototype to use for random messes.
+    /// </summary>
+    [DataField(required: true)]
+    public ProtoId<WeightedRandomFillSolutionPrototype> RandomPuddleSolutionFill = default!;
+}

Content.Server/GameTicking/Rules/VariationPass/Components/ReinforcedWallReplaceVariationPassComponent.cs

@@ -0,0 +1,7 @@
+namespace Content.Server.GameTicking.Rules.VariationPass.Components;
+
+
+[RegisterComponent]
+public sealed partial class ReinforcedWallReplaceVariationPassComponent : Component
+{
+}

Content.Server/GameTicking/Rules/VariationPass/Components/ReplacementMarkers/ReinforcedWallReplacementMarkerComponent.cs

@@ -0,0 +1,9 @@
+namespace Content.Server.GameTicking.Rules.VariationPass.Components.ReplacementMarkers;
+
+/// <summary>
+/// This component marks replaceable reinforced walls for use with fast queries in variation passes.
+/// </summary>
+[RegisterComponent]
+public sealed partial class ReinforcedWallReplacementMarkerComponent : Component
+{
+}

Content.Server/GameTicking/Rules/VariationPass/Components/ReplacementMarkers/WallReplacementMarkerComponent.cs

@@ -0,0 +1,9 @@
+namespace Content.Server.GameTicking.Rules.VariationPass.Components.ReplacementMarkers;
+
+/// <summary>
+/// This component marks replaceable walls for use with fast queries in variation passes.
+/// </summary>
+[RegisterComponent]
+public sealed partial class WallReplacementMarkerComponent : Component
+{
+}

Content.Server/GameTicking/Rules/VariationPass/Components/WallReplaceVariationPassComponent.cs

@@ -0,0 +1,7 @@
+namespace Content.Server.GameTicking.Rules.VariationPass.Components;
+
+
+[RegisterComponent]
+public sealed partial class WallReplaceVariationPassComponent : Component
+{
+}

Content.Server/GameTicking/Rules/VariationPass/EntitySpawnVariationPassSystem.cs

@@ -0,0 +1,29 @@
+using Content.Server.GameTicking.Rules.VariationPass.Components;
+using Content.Shared.Storage;
+using Robust.Shared.Random;
+
+namespace Content.Server.GameTicking.Rules.VariationPass;
+
+/// <inheritdoc cref="EntitySpawnVariationPassComponent"/>
+public sealed class EntitySpawnVariationPassSystem : VariationPassSystem<EntitySpawnVariationPassComponent>
+{
+    protected override void ApplyVariation(Entity<EntitySpawnVariationPassComponent> ent, ref StationVariationPassEvent args)
+    {
+        var totalTiles = Stations.GetTileCount(args.Station);
+
+        var dirtyMod = Random.NextGaussian(ent.Comp.TilesPerEntityAverage, ent.Comp.TilesPerEntityStdDev);
+        var trashTiles = Math.Max((int) (totalTiles * (1 / dirtyMod)), 0);
+
+        for (var i = 0; i < trashTiles; i++)
+        {
+            if (!TryFindRandomTileOnStation(args.Station, out _, out _, out var coords))
+                continue;
+
+            var ents = EntitySpawnCollection.GetSpawns(ent.Comp.Entities, Random);
+            foreach (var spawn in ents)
+            {
+                SpawnAtPosition(spawn, coords);
+            }
+        }
+    }
+}

Content.Server/GameTicking/Rules/VariationPass/PoweredLightVariationPassSystem.cs

@@ -0,0 +1,51 @@
+using Content.Server.GameTicking.Rules.VariationPass.Components;
+using Content.Server.Light.Components;
+using Content.Server.Light.EntitySystems;
+using Content.Shared.Light.Components;
+using Robust.Shared.Random;
+
+namespace Content.Server.GameTicking.Rules.VariationPass;
+
+/// <inheritdoc cref="PoweredLightVariationPassComponent"/>
+public sealed class PoweredLightVariationPassSystem : VariationPassSystem<PoweredLightVariationPassComponent>
+{
+    [Dependency] private readonly PoweredLightSystem _poweredLight = default!;
+
+    protected override void ApplyVariation(Entity<PoweredLightVariationPassComponent> ent, ref StationVariationPassEvent args)
+    {
+        var query = AllEntityQuery<PoweredLightComponent, TransformComponent>();
+        while (query.MoveNext(out var uid, out var comp, out var xform))
+        {
+            if (!IsMemberOfStation((uid, xform), ref args))
+                continue;
+
+            if (Random.Prob(ent.Comp.LightBreakChance))
+            {
+                var proto = comp.BulbType switch
+                {
+                    LightBulbType.Tube => ent.Comp.BrokenLightTubePrototype,
+                    _ => ent.Comp.BrokenLightBulbPrototype,
+                };
+
+                _poweredLight.ReplaceSpawnedPrototype((uid, comp), proto);
+                continue;
+            }
+
+            if (!Random.Prob(ent.Comp.LightAgingChance))
+                continue;
+
+            if (comp.BulbType == LightBulbType.Tube)
+            {
+                // some aging fluorescents (tubes) start to flicker
+                // its also way too annoying right now so we wrap it in another prob lol
+                if (Random.Prob(ent.Comp.AgedLightTubeFlickerChance))
+                    _poweredLight.ToggleBlinkingLight(uid, comp, true);
+                _poweredLight.ReplaceSpawnedPrototype((uid, comp), ent.Comp.AgedLightTubePrototype);
+            }
+            else
+            {
+                _poweredLight.ReplaceSpawnedPrototype((uid, comp), ent.Comp.AgedLightBulbPrototype);
+            }
+        }
+    }
+}

Content.Server/GameTicking/Rules/VariationPass/PuddleMessVariationPassSystem.cs

@@ -0,0 +1,35 @@
+using Content.Server.Fluids.EntitySystems;
+using Content.Server.GameTicking.Rules.VariationPass.Components;
+using Content.Shared.Chemistry.Components;
+using Content.Shared.Random.Helpers;
+using Robust.Shared.Prototypes;
+using Robust.Shared.Random;
+
+namespace Content.Server.GameTicking.Rules.VariationPass;
+
+/// <inheritdoc cref="PuddleMessVariationPassComponent"/>
+public sealed class PuddleMessVariationPassSystem : VariationPassSystem<PuddleMessVariationPassComponent>
+{
+    [Dependency] private readonly PuddleSystem _puddle = default!;
+    [Dependency] private readonly IPrototypeManager _proto = default!;
+
+    protected override void ApplyVariation(Entity<PuddleMessVariationPassComponent> ent, ref StationVariationPassEvent args)
+    {
+        var totalTiles = Stations.GetTileCount(args.Station);
+
+        if (!_proto.TryIndex(ent.Comp.RandomPuddleSolutionFill, out var proto))
+            return;
+
+        var puddleMod = Random.NextGaussian(ent.Comp.TilesPerSpillAverage, ent.Comp.TilesPerSpillStdDev);
+        var puddleTiles = Math.Max((int) (totalTiles * (1 / puddleMod)), 0);
+
+        for (var i = 0; i < puddleTiles; i++)
+        {
+            if (!TryFindRandomTileOnStation(args.Station, out _, out _, out var coords))
+                continue;
+
+            var sol = proto.Pick(Random);
+            _puddle.TrySpillAt(coords, new Solution(sol.reagent, sol.quantity), out _, sound: false);
+        }
+    }
+}

Content.Server/GameTicking/Rules/VariationPass/ReinforcedWallReplaceVariationPassSystem.cs

@@ -0,0 +1,11 @@
+using Content.Server.GameTicking.Rules.VariationPass.Components;
+using Content.Server.GameTicking.Rules.VariationPass.Components.ReplacementMarkers;
+
+namespace Content.Server.GameTicking.Rules.VariationPass;
+
+/// <summary>
+/// This handles the ability to replace entities marked with <see cref="ReinforcedWallReplacementMarkerComponent"/> in a variation pass
+/// </summary>
+public sealed class ReinforcedWallReplaceVariationPassSystem : BaseEntityReplaceVariationPassSystem<ReinforcedWallReplacementMarkerComponent, ReinforcedWallReplaceVariationPassComponent>
+{
+}

Content.Server/GameTicking/Rules/VariationPass/VariationPassSystem.cs

@@ -0,0 +1,29 @@
+using Content.Server.Station.Systems;
+using Robust.Shared.Random;
+
+namespace Content.Server.GameTicking.Rules.VariationPass;
+
+/// <summary>
+///     Base class for procedural variation rule passes, which apply some kind of variation to a station,
+///     so we simply reduce the boilerplate for the event handling a bit with this.
+/// </summary>
+public abstract class VariationPassSystem<T> : GameRuleSystem<T>
+    where T: IComponent
+{
+    [Dependency] protected readonly StationSystem Stations = default!;
+    [Dependency] protected readonly IRobustRandom Random = default!;
+
+    public override void Initialize()
+    {
+        base.Initialize();
+
+        SubscribeLocalEvent<T, StationVariationPassEvent>(ApplyVariation);
+    }
+
+    protected bool IsMemberOfStation(Entity<TransformComponent> ent, ref StationVariationPassEvent args)
+    {
+        return Stations.GetOwningStation(ent, ent.Comp) == args.Station.Owner;
+    }
+
+    protected abstract void ApplyVariation(Entity<T> ent, ref StationVariationPassEvent args);
+}

Content.Server/GameTicking/Rules/VariationPass/WallReplaceVariationPassSystem.cs

@@ -0,0 +1,11 @@
+using Content.Server.GameTicking.Rules.VariationPass.Components;
+using Content.Server.GameTicking.Rules.VariationPass.Components.ReplacementMarkers;
+
+namespace Content.Server.GameTicking.Rules.VariationPass;
+
+/// <summary>
+/// This handles the ability to replace entities marked with <see cref="WallReplacementMarkerComponent"/> in a variation pass
+/// </summary>
+public sealed class WallReplaceVariationPassSystem : BaseEntityReplaceVariationPassSystem<WallReplacementMarkerComponent, WallReplaceVariationPassComponent>
+{
+}