Only auto-enable internals when necessary (#28248)

* Only auto-enable internals when necessary

* Add toxic gas check

* Rename Any -> AnyPositive

Content.Server/Body/Systems/LungSystem.cs

@@ -3,6 +3,7 @@ using Content.Server.Atmos.EntitySystems;
 using Content.Server.Body.Components;
 using Content.Server.Chemistry.Containers.EntitySystems;
 using Content.Shared.Atmos;
+using Content.Shared.Chemistry.Components;
 using Content.Shared.Clothing;
 using Content.Shared.Inventory.Events;
 
@@ -77,23 +78,32 @@ public sealed class LungSystem : EntitySystem
         if (!_solutionContainerSystem.ResolveSolution(uid, lung.SolutionName, ref lung.Solution, out var solution))
             return;
 
-        foreach (var gas in Enum.GetValues<Gas>())
+        GasToReagent(lung.Air, solution);
+        _solutionContainerSystem.UpdateChemicals(lung.Solution.Value);
+    }
+
+    private void GasToReagent(GasMixture gas, Solution solution)
+    {
+        foreach (var gasId in Enum.GetValues<Gas>())
         {
-            var i = (int) gas;
-            var moles = lung.Air[i];
+            var i = (int) gasId;
+            var moles = gas[i];
             if (moles <= 0)
                 continue;
+
             var reagent = _atmosphereSystem.GasReagents[i];
-            if (reagent is null) continue;
+            if (reagent is null)
+                continue;
 
             var amount = moles * Atmospherics.BreathMolesToReagentMultiplier;
             solution.AddReagent(reagent, amount);
-
-            // We don't remove the gas from the lung mix,
-            // that's the responsibility of whatever gas is being metabolized.
-            // Most things will just want to exhale again.
         }
+    }
 
-        _solutionContainerSystem.UpdateChemicals(lung.Solution.Value);
+    public Solution GasToReagent(GasMixture gas)
+    {
+        var solution = new Solution();
+        GasToReagent(gas, solution);
+        return solution;
     }
 }