Convert StomachBehavior to a component/system + rejig body namespaces (#5249)

* Convert StomachBehavior to a component/system + rejig body namespaces

* test

* slightly more namespace changes

* remove

* Hello?????

* fuck you github test runner

* reviews

* oobsy!

Content.Server/Body/Components/BloodstreamComponent.cs

@@ -0,0 +1,102 @@
+using System;
+using Content.Server.Atmos;
+using Content.Server.Atmos.EntitySystems;
+using Content.Server.Chemistry.EntitySystems;
+using Content.Shared.Atmos;
+using Content.Shared.Body.Components;
+using Content.Shared.Chemistry.Components;
+using Content.Shared.FixedPoint;
+using Robust.Shared.GameObjects;
+using Robust.Shared.Serialization.Manager.Attributes;
+using Robust.Shared.ViewVariables;
+
+namespace Content.Server.Body.Components
+{
+    [RegisterComponent]
+    [ComponentReference(typeof(SharedBloodstreamComponent))]
+    public class BloodstreamComponent : SharedBloodstreamComponent, IGasMixtureHolder
+    {
+        public override string Name => "Bloodstream";
+
+        /// <summary>
+        ///     Max volume of internal solution storage
+        /// </summary>
+        [DataField("maxVolume")] [ViewVariables]
+        private FixedPoint2 _initialMaxVolume = FixedPoint2.New(250);
+
+        /// <summary>
+        ///     Internal solution for reagent storage
+        /// </summary>
+        [ViewVariables] private Solution? _internalSolution;
+
+        /// <summary>
+        ///     Empty volume of internal solution
+        /// </summary>
+        [ViewVariables]
+        public FixedPoint2 EmptyVolume => _internalSolution?.AvailableVolume ?? FixedPoint2.Zero;
+
+        [ViewVariables]
+        public GasMixture Air { get; set; } = new(6)
+            { Temperature = Atmospherics.NormalBodyTemperature };
+
+        protected override void Initialize()
+        {
+            base.Initialize();
+
+            _internalSolution = EntitySystem.Get<SolutionContainerSystem>().EnsureSolution(Owner.Uid, DefaultSolutionName);
+            if (_internalSolution != null)
+            {
+                _internalSolution.MaxVolume = _initialMaxVolume;
+            }
+        }
+
+        /// <summary>
+        ///     Attempt to transfer provided solution to internal solution.
+        ///     Only supports complete transfers
+        /// </summary>
+        /// <param name="solution">Solution to be transferred</param>
+        /// <returns>Whether or not transfer was a success</returns>
+        public override bool TryTransferSolution(Solution solution)
+        {
+            // For now doesn't support partial transfers
+            var current = _internalSolution?.CurrentVolume ?? FixedPoint2.Zero;
+            var max = _internalSolution?.MaxVolume ?? FixedPoint2.Zero;
+            if (solution.TotalVolume + current > max)
+            {
+                return false;
+            }
+
+            EntitySystem.Get<SolutionContainerSystem>().TryAddSolution(Owner.Uid, _internalSolution, solution);
+            return true;
+        }
+
+        public void PumpToxins(GasMixture to)
+        {
+            var atmosphereSystem = EntitySystem.Get<AtmosphereSystem>();
+
+            if (!Owner.TryGetComponent(out RespiratorComponent? metabolism))
+            {
+                atmosphereSystem.Merge(to, Air);
+                Air.Clear();
+                return;
+            }
+
+            var toxins = metabolism.Clean(this);
+            var toOld = new float[to.Moles.Length];
+            Array.Copy(to.Moles, toOld, toOld.Length);
+
+            atmosphereSystem.Merge(to, toxins);
+
+            for (var i = 0; i < toOld.Length; i++)
+            {
+                var newAmount = to.GetMoles(i);
+                var oldAmount = toOld[i];
+                var delta = newAmount - oldAmount;
+
+                toxins.AdjustMoles(i, -delta);
+            }
+
+            atmosphereSystem.Merge(Air, toxins);
+        }
+    }
+}