Space cleaner buffs (#15779)

Content.Server/Chemistry/TileReactions/CleanDecalsReaction.cs

@@ -0,0 +1,55 @@
+using Content.Server.Decals;
+using Content.Shared.Chemistry.Reaction;
+using Content.Shared.Chemistry.Reagent;
+using Content.Shared.Decals;
+using Content.Shared.FixedPoint;
+using Robust.Shared.Map;
+using Robust.Shared.Map.Components;
+
+namespace Content.Server.Chemistry.TileReactions;
+
+/// <summary>
+/// Purges all cleanable decals on a tile.
+/// </summary>
+[DataDefinition]
+public sealed class CleanDecalsReaction : ITileReaction
+{
+    /// <summary>
+    /// For every cleaned decal we lose this much reagent.
+    /// </summary>
+    [DataField("cleanCost")]
+    public FixedPoint2 CleanCost { get; private set; } = FixedPoint2.New(0.25f);
+
+    public FixedPoint2 TileReact(TileRef tile, ReagentPrototype reagent, FixedPoint2 reactVolume)
+    {
+        var entMan = IoCManager.Resolve<IEntityManager>();
+
+        if (reactVolume <= CleanCost ||
+            !entMan.TryGetComponent<MapGridComponent>(tile.GridUid, out var grid) ||
+            !entMan.TryGetComponent<DecalGridComponent>(tile.GridUid, out var decalGrid))
+        {
+            return FixedPoint2.Zero;
+        }
+
+        var lookupSystem = entMan.System<EntityLookupSystem>();
+        var decalSystem = entMan.System<DecalSystem>();
+        // Very generous hitbox.
+        var decals = decalSystem
+            .GetDecalsIntersecting(tile.GridUid, lookupSystem.GetLocalBounds(tile, grid.TileSize).Enlarged(0.5f).Translated(new Vector2(-0.5f, -0.5f)));
+        var amount = FixedPoint2.Zero;
+
+        foreach (var decal in decals)
+        {
+            if (!decal.Decal.Cleanable)
+                continue;
+
+            decalSystem.RemoveDecal(tile.GridUid, decal.Index, decalGrid);
+            amount += CleanCost;
+
+            if (amount > reactVolume)
+                break;
+        }
+
+        return amount;
+    }
+}