Remove LungBehavior and replace with LungComponent/System (#5630)

Content.Client/Entry/IgnoredComponents.cs

@@ -116,6 +116,7 @@ namespace Content.Client.Entry
             "PowerSupplier",
             "PowerConsumer",
             "Battery",
+            "Lung",
             "BatteryDischarger",
             "Apc",
             "PowerProvider",

Content.IntegrationTests/Tests/Body/LungTest.cs

@@ -1,10 +1,9 @@
 using System;
-using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
 using Content.Server.Atmos;
-using Content.Server.Body.Behavior;
 using Content.Server.Body.Components;
+using Content.Server.Body.Systems;
 using Content.Shared.Atmos;
 using Content.Shared.Body.Components;
 using NUnit.Framework;
@@ -17,7 +16,7 @@ using Robust.Shared.Maths;
 namespace Content.IntegrationTests.Tests.Body
 {
     [TestFixture]
-    [TestOf(typeof(LungBehavior))]
+    [TestOf(typeof(LungSystem))]
     public class LungTest : ContentIntegrationTest
     {
         private const string Prototypes = @"
@@ -64,8 +63,12 @@ namespace Content.IntegrationTests.Tests.Body
 
                 var human = entityManager.SpawnEntity("HumanBodyAndBloodstreamDummy", new MapCoordinates(Vector2.Zero, mapId));
 
+                var bodySys = EntitySystem.Get<BodySystem>();
+                var lungSys = EntitySystem.Get<LungSystem>();
+
                 Assert.That(human.TryGetComponent(out SharedBodyComponent body));
-                Assert.That(body.TryGetMechanismBehaviors(out List<LungBehavior> lungs));
+
+                var lungs = bodySys.GetComponentsOnMechanisms<LungComponent>(human.Uid, body).ToArray();
                 Assert.That(lungs.Count, Is.EqualTo(1));
                 Assert.That(human.TryGetComponent(out BloodstreamComponent bloodstream));
 
@@ -78,8 +81,8 @@ namespace Content.IntegrationTests.Tests.Body
                 gas.AdjustMoles(Gas.Oxygen, originalOxygen);
                 gas.AdjustMoles(Gas.Nitrogen, originalNitrogen);
 
-                var lung = lungs[0];
+                var (lung, _) = lungs[0];
-                lung.Inhale(1, gas);
+                lungSys.TakeGasFrom(lung.OwnerUid, 1, gas, lung);
 
                 var lungOxygen = originalOxygen * breathedPercentage;
                 var lungNitrogen = originalNitrogen * breathedPercentage;
@@ -100,7 +103,7 @@ namespace Content.IntegrationTests.Tests.Body
                 Assert.Zero(lungOxygenBeforeExhale);
                 Assert.Zero(lungNitrogenBeforeExhale);
 
-                lung.Exhale(1, gas);
+                lungSys.PushGasTo(lung.OwnerUid, gas, lung);
 
                 var lungOxygenAfterExhale = lung.Air.GetMoles(Gas.Oxygen);
                 var exhaledOxygen = Math.Abs(lungOxygenBeforeExhale - lungOxygenAfterExhale);
@@ -168,8 +171,7 @@ namespace Content.IntegrationTests.Tests.Body
                 var coordinates = new EntityCoordinates(grid.GridEntityId, center);
                 human = entityManager.SpawnEntity("HumanBodyAndBloodstreamDummy", coordinates);
 
-                Assert.True(human.TryGetComponent(out SharedBodyComponent body));
+                Assert.True(human.HasComponent<SharedBodyComponent>());
-                Assert.True(body.HasMechanismBehavior<LungBehavior>());
                 Assert.True(human.TryGetComponent(out respirator));
                 Assert.False(respirator.Suffocating);
             });

Content.Server/Body/Behavior/LungBehavior.cs

@@ -1,205 +0,0 @@
-using System;
-using Content.Server.Atmos;
-using Content.Server.Atmos.Components;
-using Content.Server.Atmos.EntitySystems;
-using Content.Server.Body.Components;
-using Content.Server.Body.Systems;
-using Content.Server.Popups;
-using Content.Shared.Atmos;
-using Content.Shared.Body.Components;
-using Content.Shared.MobState;
-using Content.Shared.MobState.Components;
-using Robust.Shared.GameObjects;
-using Robust.Shared.IoC;
-using Robust.Shared.Localization;
-using Robust.Shared.Serialization;
-using Robust.Shared.Serialization.Manager.Attributes;
-using Robust.Shared.Timing;
-using Robust.Shared.ViewVariables;
-
-namespace Content.Server.Body.Behavior
-{
-    [DataDefinition]
-    public class LungBehavior : MechanismBehavior, ISerializationHooks
-    {
-        [Dependency] private readonly IGameTiming _gameTiming = default!;
-
-        private float _accumulatedFrameTime;
-
-        [ViewVariables] private TimeSpan _lastGaspPopupTime;
-
-        [DataField("air")]
-        [ViewVariables]
-        public GasMixture Air { get; set; } = new()
-        {
-            Volume = 6,
-            Temperature = Atmospherics.NormalBodyTemperature
-        };
-
-        [DataField("gaspPopupCooldown")]
-        [ViewVariables]
-        public TimeSpan GaspPopupCooldown { get; private set; } = TimeSpan.FromSeconds(8);
-
-        [ViewVariables] public LungStatus Status { get; set; }
-
-        [DataField("cycleDelay")]
-        [ViewVariables]
-        public float CycleDelay { get; set; } = 2;
-
-        void ISerializationHooks.AfterDeserialization()
-        {
-            IoCManager.InjectDependencies(this);
-        }
-
-        protected override void OnAddedToBody(SharedBodyComponent body)
-        {
-            base.OnAddedToBody(body);
-            Inhale(CycleDelay);
-        }
-
-        public void Gasp()
-        {
-            if (_gameTiming.CurTime >= _lastGaspPopupTime + GaspPopupCooldown)
-            {
-                _lastGaspPopupTime = _gameTiming.CurTime;
-                Owner.PopupMessageEveryone(Loc.GetString("lung-behavior-gasp"));
-            }
-
-            Inhale(CycleDelay);
-        }
-
-        public void Transfer(GasMixture from, GasMixture to, float ratio)
-        {
-            EntitySystem.Get<AtmosphereSystem>().Merge(to, from.RemoveRatio(ratio));
-        }
-
-        public void ToBloodstream(GasMixture mixture)
-        {
-            if (Body == null)
-            {
-                return;
-            }
-
-            if (!Body.Owner.TryGetComponent(out BloodstreamComponent? bloodstream))
-            {
-                return;
-            }
-
-            var to = bloodstream.Air;
-
-            EntitySystem.Get<AtmosphereSystem>().Merge(to, mixture);
-            mixture.Clear();
-        }
-
-        public override void Update(float frameTime)
-        {
-            if (Body != null && Body.Owner.TryGetComponent(out MobStateComponent? mobState) && mobState.IsCritical())
-            {
-                return;
-            }
-
-            if (Status == LungStatus.None)
-            {
-                Status = LungStatus.Inhaling;
-            }
-
-            _accumulatedFrameTime += Status switch
-            {
-                LungStatus.Inhaling => frameTime,
-                LungStatus.Exhaling => -frameTime,
-                _ => throw new ArgumentOutOfRangeException()
-            };
-
-            var absoluteTime = Math.Abs(_accumulatedFrameTime);
-            var delay = CycleDelay;
-
-            if (absoluteTime < delay)
-            {
-                return;
-            }
-
-            switch (Status)
-            {
-                case LungStatus.Inhaling:
-                    Inhale(absoluteTime);
-                    Status = LungStatus.Exhaling;
-                    break;
-                case LungStatus.Exhaling:
-                    Exhale(absoluteTime);
-                    Status = LungStatus.Inhaling;
-                    break;
-                default:
-                    throw new ArgumentOutOfRangeException();
-            }
-
-            _accumulatedFrameTime = absoluteTime - delay;
-        }
-
-        public void Inhale(float frameTime)
-        {
-            if (Body != null &&
-                Body.Owner.TryGetComponent(out InternalsComponent? internals) &&
-                internals.BreathToolEntity != null &&
-                internals.GasTankEntity != null &&
-                internals.BreathToolEntity.TryGetComponent(out BreathToolComponent? breathTool) &&
-                breathTool.IsFunctional &&
-                internals.GasTankEntity.TryGetComponent(out GasTankComponent? gasTank) &&
-                gasTank.Air != null)
-            {
-                Inhale(frameTime, gasTank.RemoveAirVolume(Atmospherics.BreathVolume));
-                return;
-            }
-
-            if (EntitySystem.Get<AtmosphereSystem>().GetTileMixture(Owner.Transform.Coordinates, true) is not {} tileAir)
-            {
-                return;
-            }
-
-            Inhale(frameTime, tileAir);
-        }
-
-        public void Inhale(float frameTime, GasMixture from)
-        {
-            var ratio = (Atmospherics.BreathVolume / from.Volume) * frameTime;
-
-            Transfer(from, Air, ratio);
-            ToBloodstream(Air);
-        }
-
-        public void Exhale(float frameTime)
-        {
-            if (EntitySystem.Get<AtmosphereSystem>().GetTileMixture(Owner.Transform.Coordinates, true) is not {} tileAir)
-            {
-                return;
-            }
-
-            Exhale(frameTime, tileAir);
-        }
-
-        public void Exhale(float frameTime, GasMixture to)
-        {
-            // TODO: Make the bloodstream separately pump toxins into the lungs, making the lungs' only job to empty.
-            if (Body == null)
-            {
-                return;
-            }
-
-            if (!Body.Owner.TryGetComponent(out BloodstreamComponent? bloodstream))
-            {
-                return;
-            }
-
-            EntitySystem.Get<BloodstreamSystem>().PumpToxins(Body.OwnerUid, Air, bloodstream);
-
-            var lungRemoved = Air.RemoveRatio(0.5f);
-            EntitySystem.Get<AtmosphereSystem>().Merge(to, lungRemoved);
-        }
-    }
-
-    public enum LungStatus
-    {
-        None = 0,
-        Inhaling,
-        Exhaling
-    }
-}

Content.Server/Body/Components/LungComponent.cs

@@ -0,0 +1,44 @@
+using System;
+using Content.Server.Atmos;
+using Content.Server.Body.Systems;
+using Content.Shared.Atmos;
+using Robust.Shared.Analyzers;
+using Robust.Shared.GameObjects;
+using Robust.Shared.Serialization.Manager.Attributes;
+using Robust.Shared.ViewVariables;
+
+namespace Content.Server.Body.Components;
+
+[RegisterComponent, Friend(typeof(LungSystem))]
+public class LungComponent : Component
+{
+    public override string Name => "Lung";
+
+    public float AccumulatedFrametime;
+
+    [ViewVariables]
+    public TimeSpan LastGaspPopupTime;
+
+    [DataField("air")]
+    public GasMixture Air { get; set; } = new()
+    {
+        Volume = 6,
+        Temperature = Atmospherics.NormalBodyTemperature
+    };
+
+    [DataField("gaspPopupCooldown")]
+    public TimeSpan GaspPopupCooldown { get; private set; } = TimeSpan.FromSeconds(8);
+
+    [ViewVariables]
+    public LungStatus Status { get; set; }
+
+    [DataField("cycleDelay")]
+    public float CycleDelay { get; set; } = 2;
+}
+
+public enum LungStatus
+{
+    None = 0,
+    Inhaling,
+    Exhaling
+}

Content.Server/Body/Systems/BodySystem.cs

@@ -40,8 +40,15 @@ namespace Content.Server.Body.Systems
             }
         }
 
-        public IEnumerable<T> GetComponentsOnMechanisms<T>(EntityUid uid,
+        /// <summary>
-            SharedBodyComponent? body) where T : Component
+        ///     Returns a list of ValueTuples of <see cref="T"/> and SharedMechanismComponent on each mechanism
+        ///     in the given body.
+        /// </summary>
+        /// <param name="uid">The entity to check for the component on.</param>
+        /// <param name="body">The body to check for mechanisms on.</param>
+        /// <typeparam name="T">The component to check for.</typeparam>
+        public IEnumerable<(T Comp, SharedMechanismComponent Mech)> GetComponentsOnMechanisms<T>(EntityUid uid,
+            SharedBodyComponent? body=null) where T : Component
         {
             if (!Resolve(uid, ref body))
                 yield break;
@@ -50,13 +57,22 @@ namespace Content.Server.Body.Systems
             foreach (var mechanism in part.Mechanisms)
             {
                 if (EntityManager.TryGetComponent<T>(mechanism.OwnerUid, out var comp))
-                    yield return comp;
+                    yield return (comp, mechanism);
             }
         }
 
+        /// <summary>
+        ///     Tries to get a list of ValueTuples of <see cref="T"/> and SharedMechanismComponent on each mechanism
+        ///     in the given body.
+        /// </summary>
+        /// <param name="uid">The entity to check for the component on.</param>
+        /// <param name="comps">The list of components.</param>
+        /// <param name="body">The body to check for mechanisms on.</param>
+        /// <typeparam name="T">The component to check for.</typeparam>
+        /// <returns>Whether any were found.</returns>
         public bool TryGetComponentsOnMechanisms<T>(EntityUid uid,
-            [NotNullWhen(true)] out IEnumerable<T>? comps,
+            [NotNullWhen(true)] out IEnumerable<(T Comp, SharedMechanismComponent Mech)>? comps,
-            SharedBodyComponent? body) where T: Component
+            SharedBodyComponent? body=null) where T: Component
         {
             if (!Resolve(uid, ref body))
             {

Content.Server/Body/Systems/LungSystem.cs

@@ -0,0 +1,200 @@
+using System;
+using Content.Server.Atmos;
+using Content.Server.Atmos.Components;
+using Content.Server.Atmos.EntitySystems;
+using Content.Server.Body.Components;
+using Content.Server.Popups;
+using Content.Shared.Atmos;
+using Content.Shared.Body.Components;
+using Content.Shared.Body.Events;
+using Content.Shared.MobState.Components;
+using Robust.Shared.GameObjects;
+using Robust.Shared.IoC;
+using Robust.Shared.Localization;
+using Robust.Shared.Player;
+using Robust.Shared.Timing;
+
+namespace Content.Server.Body.Systems;
+
+public class LungSystem : EntitySystem
+{
+    [Dependency] private readonly IGameTiming _gameTiming = default!;
+    [Dependency] private readonly AtmosphereSystem _atmosSys = default!;
+    [Dependency] private readonly BloodstreamSystem _bloodstreamSystem = default!;
+    [Dependency] private readonly PopupSystem _popupSystem = default!;
+
+    public override void Initialize()
+    {
+        base.Initialize();
+        SubscribeLocalEvent<LungComponent, AddedToBodyEvent>(OnAddedToBody);
+    }
+
+    private void OnAddedToBody(EntityUid uid, LungComponent component, AddedToBodyEvent args)
+    {
+        Inhale(uid, component.CycleDelay);
+    }
+
+    public void Gasp(EntityUid uid,
+        LungComponent? lung=null,
+        SharedMechanismComponent? mech=null)
+    {
+        if (!Resolve(uid, ref lung))
+            return;
+
+        if (_gameTiming.CurTime >= lung.LastGaspPopupTime + lung.GaspPopupCooldown)
+        {
+            lung.LastGaspPopupTime = _gameTiming.CurTime;
+            _popupSystem.PopupEntity(Loc.GetString("lung-behavior-gasp"), uid, Filter.Pvs(uid));
+        }
+
+        Inhale(uid, lung.CycleDelay);
+    }
+
+    public void UpdateLung(EntityUid uid, float frameTime,
+        LungComponent? lung=null,
+        SharedMechanismComponent? mech=null)
+    {
+        if (!Resolve(uid, ref lung, ref mech))
+            return;
+
+        if (mech.Body != null && EntityManager.TryGetComponent(mech.Body.OwnerUid, out MobStateComponent? mobState) && mobState.IsCritical())
+        {
+            return;
+        }
+
+        if (lung.Status == LungStatus.None)
+        {
+            lung.Status = LungStatus.Inhaling;
+        }
+
+        lung.AccumulatedFrametime += lung.Status switch
+        {
+            LungStatus.Inhaling => frameTime,
+            LungStatus.Exhaling => -frameTime,
+            _ => throw new ArgumentOutOfRangeException()
+        };
+
+        var absoluteTime = Math.Abs(lung.AccumulatedFrametime);
+        var delay = lung.CycleDelay;
+
+        if (absoluteTime < delay)
+        {
+            return;
+        }
+
+        switch (lung.Status)
+        {
+            case LungStatus.Inhaling:
+                Inhale(uid, absoluteTime);
+                lung.Status = LungStatus.Exhaling;
+                break;
+            case LungStatus.Exhaling:
+                Exhale(uid, absoluteTime);
+                lung.Status = LungStatus.Inhaling;
+                break;
+            default:
+                throw new ArgumentOutOfRangeException();
+        }
+
+        lung.AccumulatedFrametime = absoluteTime - delay;
+    }
+
+    /// <summary>
+    ///     Tries to find an air mixture to inhale from, then inhales from it.
+    /// </summary>
+    public void Inhale(EntityUid uid, float frameTime,
+        LungComponent? lung=null,
+        SharedMechanismComponent? mech=null)
+    {
+        if (!Resolve(uid, ref lung, ref mech))
+            return;
+
+        // TODO Jesus Christ make this event based.
+        if (mech.Body != null &&
+            EntityManager.TryGetComponent(mech.Body.OwnerUid, out InternalsComponent? internals) &&
+            internals.BreathToolEntity != null &&
+            internals.GasTankEntity != null &&
+            internals.BreathToolEntity.TryGetComponent(out BreathToolComponent? breathTool) &&
+            breathTool.IsFunctional &&
+            internals.GasTankEntity.TryGetComponent(out GasTankComponent? gasTank))
+        {
+            TakeGasFrom(uid, frameTime, gasTank.RemoveAirVolume(Atmospherics.BreathVolume), lung);
+            return;
+        }
+
+        if (_atmosSys.GetTileMixture(EntityManager.GetComponent<TransformComponent>(uid).Coordinates, true) is not { } tileAir)
+        {
+            return;
+        }
+
+        TakeGasFrom(uid, frameTime, tileAir, lung);
+    }
+
+    /// <summary>
+    ///     Inhales directly from a given mixture.
+    /// </summary>
+    public void TakeGasFrom(EntityUid uid, float frameTime, GasMixture from,
+        LungComponent? lung=null,
+        SharedMechanismComponent? mech=null)
+    {
+        if (!Resolve(uid, ref lung, ref mech))
+            return;
+
+        var ratio = (Atmospherics.BreathVolume / from.Volume) * frameTime;
+
+        _atmosSys.Merge(lung.Air, from.RemoveRatio(ratio));
+
+        // Push to bloodstream
+        if (mech.Body == null)
+            return;
+
+        if (!EntityManager.TryGetComponent(mech.Body.OwnerUid, out BloodstreamComponent? bloodstream))
+            return;
+
+        var to = bloodstream.Air;
+
+        _atmosSys.Merge(to, lung.Air);
+        lung.Air.Clear();
+    }
+
+    /// <summary>
+    ///     Tries to find a gas mixture to exhale to, then pushes gas to it.
+    /// </summary>
+    public void Exhale(EntityUid uid, float frameTime,
+        LungComponent? lung=null,
+        SharedMechanismComponent? mech=null)
+    {
+        if (!Resolve(uid, ref lung, ref mech))
+            return;
+
+        if (_atmosSys.GetTileMixture(EntityManager.GetComponent<TransformComponent>(uid).Coordinates, true) is not { } tileAir)
+        {
+            return;
+        }
+
+        PushGasTo(uid, tileAir, lung, mech);
+    }
+
+    /// <summary>
+    ///     Pushes gas from the lungs to a gas mixture.
+    /// </summary>
+    public void PushGasTo(EntityUid uid, GasMixture to,
+        LungComponent? lung=null,
+        SharedMechanismComponent? mech=null)
+    {
+        if (!Resolve(uid, ref lung, ref mech))
+            return;
+
+        // TODO: Make the bloodstream separately pump toxins into the lungs, making the lungs' only job to empty.
+        if (mech.Body == null)
+            return;
+
+        if (!EntityManager.TryGetComponent(mech.Body.OwnerUid, out BloodstreamComponent? bloodstream))
+            return;
+
+        _bloodstreamSystem.PumpToxins(mech.Body.OwnerUid, lung.Air, bloodstream);
+
+        var lungRemoved = lung.Air.RemoveRatio(0.5f);
+        _atmosSys.Merge(to, lungRemoved);
+    }
+}

Content.Server/Body/Systems/RespiratorSystem.cs

@@ -4,7 +4,6 @@ using System.Linq;
 using Content.Server.Administration.Logs;
 using Content.Server.Alert;
 using Content.Server.Atmos;
-using Content.Server.Body.Behavior;
 using Content.Server.Body.Components;
 using Content.Shared.Alert;
 using Content.Shared.Atmos;
@@ -23,6 +22,8 @@ namespace Content.Server.Body.Systems
     {
         [Dependency] private readonly DamageableSystem _damageableSys = default!;
         [Dependency] private readonly AdminLogSystem _logSys = default!;
+        [Dependency] private readonly BodySystem _bodySystem = default!;
+        [Dependency] private readonly LungSystem _lungSystem = default!;
 
         public override void Update(float frameTime)
         {
@@ -136,10 +137,16 @@ namespace Content.Server.Body.Systems
             if (!Resolve(uid, ref bloodstream, ref body, false))
                 return;
 
-            var lungs = body.GetMechanismBehaviors<LungBehavior>().ToArray();
+            var lungs = _bodySystem.GetComponentsOnMechanisms<LungComponent>(uid, body).ToArray();
 
             var needs = NeedsAndDeficit(respirator, frameTime);
             var used = 0f;
+
+            foreach (var (lung, mech) in lungs)
+            {
+                _lungSystem.UpdateLung(lung.OwnerUid, frameTime, lung, mech);
+            }
+
             foreach (var (gas, amountNeeded) in needs)
             {
                 var bloodstreamAmount = bloodstream.Air.GetMoles(gas);
@@ -150,9 +157,9 @@ namespace Content.Server.Body.Systems
                     if (!EntityManager.GetComponent<MobStateComponent>(uid).IsCritical())
                     {
                         // Panic inhale
-                        foreach (var lung in lungs)
+                        foreach (var (lung, mech) in lungs)
                         {
-                            lung.Gasp();
+                            _lungSystem.Gasp(lung.OwnerUid, lung, mech);
                         }
                     }
 

Content.Server/Nutrition/EntitySystems/DrinkSystem.cs

@@ -27,6 +27,7 @@ using Robust.Shared.IoC;
 using Robust.Shared.Localization;
 using Robust.Shared.Player;
 using Robust.Shared.Random;
+using Robust.Shared.Utility;
 
 namespace Content.Server.Nutrition.EntitySystems
 {
@@ -263,8 +264,8 @@ namespace Content.Server.Nutrition.EntitySystems
 
             var transferAmount = FixedPoint2.Min(drink.TransferAmount, drinkSolution.DrainAvailable);
             var drain = _solutionContainerSystem.Drain(uid, drinkSolution, transferAmount);
-            var firstStomach = stomachs.FirstOrDefault(
+            var firstStomach = stomachs.FirstOrNull(
-                stomach => _stomachSystem.CanTransferSolution(stomach.OwnerUid, drain));
+                stomach => _stomachSystem.CanTransferSolution(stomach.Comp.OwnerUid, drain));
 
             // All stomach are full or can't handle whatever solution we have.
             if (firstStomach == null)
@@ -289,7 +290,7 @@ namespace Content.Server.Nutrition.EntitySystems
                 Filter.Pvs(userUid));
 
             drain.DoEntityReaction(userUid, ReactionMethod.Ingestion);
-            _stomachSystem.TryTransferSolution(firstStomach.OwnerUid, drain, firstStomach);
+            _stomachSystem.TryTransferSolution(firstStomach.Value.Comp.OwnerUid, drain, firstStomach.Value.Comp);
 
             return true;
         }
@@ -371,8 +372,8 @@ namespace Content.Server.Nutrition.EntitySystems
                 return;
             }
 
-            var firstStomach = stomachs.FirstOrDefault(
+            var firstStomach = stomachs.FirstOrNull(
-                stomach => _stomachSystem.CanTransferSolution(stomach.OwnerUid, drained));
+                stomach => _stomachSystem.CanTransferSolution(stomach.Comp.OwnerUid, drained));
 
             // All stomach are full or can't handle whatever solution we have.
             if (firstStomach == null)
@@ -399,7 +400,7 @@ namespace Content.Server.Nutrition.EntitySystems
             SoundSystem.Play(Filter.Pvs(uid), args.Drink.UseSound.GetSound(), uid, AudioParams.Default.WithVolume(-2f));
 
             drained.DoEntityReaction(uid, ReactionMethod.Ingestion);
-            _stomachSystem.TryTransferSolution(firstStomach.OwnerUid, drained, firstStomach);
+            _stomachSystem.TryTransferSolution(firstStomach.Value.Comp.OwnerUid, drained, firstStomach.Value.Comp);
         }
 
         private void OnForceDrinkCancelled(ForceDrinkCancelledEvent args)

Content.Server/Nutrition/EntitySystems/FoodSystem.cs

@@ -24,6 +24,7 @@ using Robust.Shared.Localization;
 using Robust.Shared.Player;
 using System.Collections.Generic;
 using System.Linq;
+using Robust.Shared.Utility;
 
 namespace Content.Server.Nutrition.EntitySystems
 {
@@ -144,7 +145,8 @@ namespace Content.Server.Nutrition.EntitySystems
 
             var transferAmount = component.TransferAmount != null ? FixedPoint2.Min((FixedPoint2) component.TransferAmount, solution.CurrentVolume) : solution.CurrentVolume;
             var split = _solutionContainerSystem.SplitSolution(uid, solution, transferAmount);
-            var firstStomach = stomachs.FirstOrDefault(stomach => _stomachSystem.CanTransferSolution(stomach.OwnerUid, split));
+            var firstStomach = stomachs.FirstOrNull(
+                stomach => _stomachSystem.CanTransferSolution(stomach.Comp.OwnerUid, split));
 
             if (firstStomach == null)
             {
@@ -155,7 +157,7 @@ namespace Content.Server.Nutrition.EntitySystems
 
             // TODO: Account for partial transfer.
             split.DoEntityReaction(userUid, ReactionMethod.Ingestion);
-            _stomachSystem.TryTransferSolution(firstStomach.OwnerUid, split, firstStomach);
+            _stomachSystem.TryTransferSolution(firstStomach.Value.Comp.OwnerUid, split, firstStomach.Value.Comp);
 
             SoundSystem.Play(Filter.Pvs(userUid), component.UseSound.GetSound(), userUid, AudioParams.Default.WithVolume(-1f));
             _popupSystem.PopupEntity(Loc.GetString(component.EatMessage, ("food", component.Owner)), userUid, Filter.Entities(userUid));
@@ -292,7 +294,8 @@ namespace Content.Server.Nutrition.EntitySystems
                 : args.FoodSolution.CurrentVolume;
 
             var split = _solutionContainerSystem.SplitSolution(args.Food.OwnerUid, args.FoodSolution, transferAmount);
-            var firstStomach = stomachs.FirstOrDefault(stomach => _stomachSystem.CanTransferSolution(stomach.OwnerUid, split));
+            var firstStomach = stomachs.FirstOrNull(
+                stomach => _stomachSystem.CanTransferSolution(stomach.Comp.OwnerUid, split));
 
             if (firstStomach == null)
             {
@@ -302,7 +305,7 @@ namespace Content.Server.Nutrition.EntitySystems
             }
 
             split.DoEntityReaction(uid, ReactionMethod.Ingestion);
-            _stomachSystem.TryTransferSolution(firstStomach.OwnerUid, split, firstStomach);
+            _stomachSystem.TryTransferSolution(firstStomach.Value.Comp.OwnerUid, split, firstStomach.Value.Comp);
 
             EntityManager.TryGetComponent(uid, out MetaDataComponent? targetMeta);
             var targetName = targetMeta?.EntityName ?? string.Empty;
@@ -350,7 +353,9 @@ namespace Content.Server.Nutrition.EntitySystems
             if (food.UsesRemaining <= 0)
                 DeleteAndSpawnTrash(food);
 
-            var firstStomach = stomachs.FirstOrDefault(stomach => _stomachSystem.CanTransferSolution(stomach.OwnerUid, foodSolution));
+            var firstStomach = stomachs.FirstOrNull(
+                stomach => _stomachSystem.CanTransferSolution(stomach.Comp.OwnerUid, foodSolution));
+
             if (firstStomach == null)
                 return;
 
@@ -365,7 +370,7 @@ namespace Content.Server.Nutrition.EntitySystems
             _popupSystem.PopupEntity(Loc.GetString(food.EatMessage), target, Filter.Entities(target));
 
             foodSolution.DoEntityReaction(uid, ReactionMethod.Ingestion);
-            _stomachSystem.TryTransferSolution(firstStomach.OwnerUid, foodSolution, firstStomach);
+            _stomachSystem.TryTransferSolution(firstStomach.Value.Comp.OwnerUid, foodSolution, firstStomach.Value.Comp);
             SoundSystem.Play(Filter.Pvs(target), food.UseSound.GetSound(), target, AudioParams.Default.WithVolume(-1f));
 
             if (string.IsNullOrEmpty(food.TrashPrototype))

Resources/Prototypes/Body/Mechanisms/human.yml

@@ -99,8 +99,7 @@
   - type: Mechanism
     size: 1
     compatibility: Biological
-    behaviors:
+  - type: Lung
-    - !type:LungBehavior {}
 
 - type: entity
   id: OrganHumanHeart

Resources/Prototypes/Body/Parts/animal.yml

@@ -83,8 +83,7 @@
   - type: Mechanism
     size: 1
     compatibility: Biological
-    behaviors:
+  - type: Lung
-    - !type:LungBehavior {}
 
 - type: entity
   id: OrganAnimalStomach