Add in a light level + cellar requirement for cultivating mushrooms.

Substrate/BlockEntities/BlockEntityFruitingBag.cs

@@ -49,6 +49,14 @@ internal float Fertility
         }
         private float _fertility = -1;
 
+        private bool RequiresCellarForCultivation => SubstrateModSystem.Config.RequireCellarForCultivation;
+        private int MaxCultivationLightLevel => SubstrateModSystem.Config.MaxCultivationLightLevel;
+        private bool IsInCellar() => CellarUtil.IsInCellar(Api, Pos);
+        private BlockPos LightCheckPos => Block is BlockGrowBed ? Pos.UpCopy() : Pos;
+        private int CurrentLightLevel => Api.World.BlockAccessor.GetLightLevel(LightCheckPos, EnumLightLevelType.MaxLight);
+        private bool IsLightLevelSuitable() => CurrentLightLevel <= MaxCultivationLightLevel;
+        private bool CanCultivateHere() => (!RequiresCellarForCultivation || IsInCellar()) && IsLightLevelSuitable();
+
         public override void Initialize(ICoreAPI api)
         {
             base.Initialize(api);
@@ -134,6 +142,12 @@ private void Tick(float deltaTime)
         {
             if (Api.Side != EnumAppSide.Server || !Inoculated) return;
 
+            if (!CanCultivateHere())
+            {
+                _lastColonizeProgressTimestamp = 0;
+                return;
+            }
+
             if (Fertility <= 0)
             {
                 _inoculatedMushroom = null;
@@ -209,6 +223,19 @@ public bool OnInteract(IWorldAccessor world, IPlayer byPlayer, BlockSelection bl
                 return false;
             }
 
+            if (!CanCultivateHere())
+            {
+                if (Api is ICoreClientAPI capi)
+                {
+                    var errorCode = !IsLightLevelSuitable() ? "requires-darkness" : "requires-cellar";
+                    var message = !IsLightLevelSuitable()
+                        ? Lang.Get("substrate:notice-too-bright-for-cultivation", MaxCultivationLightLevel)
+                        : Lang.Get("substrate:notice-requires-cellar");
+                    capi.TriggerIngameError(this, errorCode, message);
+                }
+                return false;
+            }
+
             _inoculatedMushroom = mushroomVariant;
             _colonizeDuration = NextColonizeIncrement();
 
@@ -250,6 +277,10 @@ public override void GetBlockInfo(IPlayer forPlayer, StringBuilder dsc)
                 dsc.AppendLine(Lang.Get("substrate:fruitingbag-remaining-fertility", Fertility / MaxFertility * 100));
                 if (GetOpenFaceCount() == 0)
                     dsc.AppendLine(Lang.Get("substrate:notice-no-available-grow-spots"));
+                if (RequiresCellarForCultivation && !IsInCellar())
+                    dsc.AppendLine(Lang.Get("substrate:notice-requires-cellar"));
+                if (!IsLightLevelSuitable())
+                    dsc.AppendLine(Lang.Get("substrate:notice-too-bright-for-cultivation", MaxCultivationLightLevel));
             }
             else
             {

Substrate/Config/SubstrateConfig.cs

@@ -0,0 +1,8 @@
+namespace Substrate.Config
+{
+    public class SubstrateConfig
+    {
+        public bool RequireCellarForCultivation { get; set; } = true;
+        public int MaxCultivationLightLevel { get; set; } = 8;
+    }
+}

Substrate/SubstrateModSystem.cs

@@ -4,6 +4,7 @@
 using Substrate.Behaviors;
 using Substrate.BlockEntities;
 using Substrate.Blocks;
+using Substrate.Config;
 using Substrate.Utils;
 using Substrate.Utils.CodecPattern;
 using Substrate.Utils.CodecPattern.Codecs;
@@ -21,12 +22,16 @@ namespace Substrate
 {
     public class SubstrateModSystem : ModSystem
     {
-        internal static ILogger Logger { get; private set; }
+        internal static ILogger? Logger { get; private set; }
+        internal static SubstrateConfig Config { get; private set; } = new();
 
         // Called on server and client
         // Useful for registering block/entity classes on both sides
         public override void Start(ICoreAPI api)
         {
+            Config = api.LoadModConfig<SubstrateConfig>("SubstrateConfig.json") ?? new SubstrateConfig();
+            api.StoreModConfig(Config, "SubstrateConfig.json");
+
             api.RegisterBlockClass("BlockFruitingBag", typeof(BlockFruitingBag));
             api.RegisterBlockClass("BlockGrowBed", typeof(BlockGrowBed));
             api.RegisterBlockEntityClass("FruitingBag", typeof(BlockEntityFruitingBag));

Substrate/Utils/CellarUtil.cs

@@ -0,0 +1,33 @@
+using System;
+using Vintagestory.API.Common;
+using Vintagestory.API.MathTools;
+using Vintagestory.GameContent;
+
+namespace Substrate.Utils
+{
+    internal static class CellarUtil
+    {
+        // Determines if the BlockPos is within a cellar
+        // This mirrors the vanilla logic for determining a cellar
+        // but unfortunately there seems to be no API that directly asks
+        // for if something is a cellar or not, we are just allowed to query
+        // the room properties and copy what vanilla does.
+        public static bool IsInCellar(ICoreAPI api, BlockPos pos)
+        {
+            try
+            {
+                var roomRegistry = api.ModLoader.GetModSystem<RoomRegistry>();
+                var room = roomRegistry?.GetRoomForPosition(pos);
+                if (room == null) return false;
+
+                return room.ExitCount == 0 && room.NonSkylightCount > 0;
+            }
+            catch (Exception ex)
+            {
+                SubstrateModSystem.Logger?.Warning($"Cellar detection failed: {ex.Message}");
+                api.Logger.Warning($"Cellar detection failed: {ex.Message}");
+                return true;
+            }
+        }
+    }
+}

Substrate/assets/substrate/lang/en.json

@@ -104,6 +104,8 @@
   "notice-moldy": "The substrate has <font color=\"orange\">molded</font>! Break to recycle.",
   "notice-no-available-grow-spots": "<font color=\"orange\">Lack of space to grow is causing fertility waste!</font>",
   "notice-cannot-grow-mushroom-with-block": "{0} can only grow in a {1}!",
+  "notice-requires-cellar": "Mushroom cultivation must be done in a cellar.",
+  "notice-too-bright-for-cultivation": "It is too bright for mushroom cultivation here. Light level must be {0} or lower.",
 
   "fruitingbag-insert-sporeprint": "Add Spore Print",
   "fruitingbag-insert-substrate": "Add Substrate",
@@ -163,4 +165,4 @@
   "mushroom-libertycap": "Liberty Cap",
   "mushroom-sickener": "Sickener",
   "mushroom-wavycap": "Wavy Cap"
-}
+}