Add hunger and thirst (#363)

* Add hunger and thirst

Based on the SS13 systems.
Food (Nutriment) / Drink -> Stomach -> Hunger / Thirst

* Cleanup rebase

* Cleanup stuff that was prototyped

* Address feedback

Still need to add a statuseffects system in a separate branch

* More cleanup on nutrition

Fix Remie's feedback and also damage tick.

* Re-implement nutrition with master

* Updated to use the StatusEffectsUI update
* Removed all clientside components as they only receive the UI updates now
* Implemented PR feedback
* Had to make a slight adjustment to the chemistry SolutionComponent given it doesn't have an Owner, same with Solution

Still TODO:
* Metabolisation effects
* Change drink contents to alcohol / wine etc.
* Add items to the dispensers
* For transparent containers use RecalculateColor

Could probably genericise DrinkFoodContainer as well to be a temporary item dispenser

* Fix broken bottle parent

Content.Server/GameObjects/Components/Nutrition/StomachComponent.cs

@@ -0,0 +1,129 @@
+using Content.Server.GameObjects.Components.Chemistry;
+using Content.Shared.Chemistry;
+using Content.Shared.GameObjects.Components.Nutrition;
+using Robust.Shared.GameObjects;
+using Robust.Shared.Serialization;
+using Robust.Shared.ViewVariables;
+
+namespace Content.Server.GameObjects.Components.Nutrition
+{
+    [RegisterComponent]
+    public class StomachComponent : SharedStomachComponent
+    {
+        // Essentially every time it ticks it'll pull out the MetabolisationAmount of reagents and process them.
+        // Generic food goes under "nutriment" like SS13
+        // There's also separate hunger and thirst components which means you can have a stomach
+        // but not require food / water.
+        public static readonly int NutrimentFactor = 30;
+        public static readonly int HydrationFactor = 30;
+        public static readonly int MetabolisationAmount = 5;
+
+        private SolutionComponent _stomachContents;
+        public float MetaboliseDelay => _metaboliseDelay;
+        [ViewVariables]
+        private float _metaboliseDelay; // How long between metabolisation for 5 units
+
+        public int MaxVolume
+        {
+            get => _stomachContents.MaxVolume;
+            set => _stomachContents.MaxVolume = value;
+        }
+
+        private float _metabolisationCounter = 0.0f;
+
+        private int _initialMaxVolume;
+
+        public override void ExposeData(ObjectSerializer serializer)
+        {
+            base.ExposeData(serializer);
+            serializer.DataField(ref _metaboliseDelay, "metabolise_delay", 6.0f);
+            serializer.DataField(ref _initialMaxVolume, "max_volume", 20);
+        }
+
+        public override void Initialize()
+        {
+            base.Initialize();
+            // Shouldn't add to Owner to avoid cross-contamination (e.g. with blood or whatever they made hold other solutions)
+            _stomachContents = new SolutionComponent();
+            _stomachContents.InitializeFromPrototype();
+            _stomachContents.MaxVolume = _initialMaxVolume;
+        }
+
+        public bool TryTransferSolution(Solution solution)
+        {
+            // TODO: For now no partial transfers. Potentially change by design
+            if (solution.TotalVolume + _stomachContents.CurrentVolume > _stomachContents.MaxVolume)
+            {
+                return false;
+            }
+            _stomachContents.TryAddSolution(solution, false, true);
+            return true;
+        }
+
+        /// <summary>
+        /// This is where the magic happens. Make people throw up, increase nutrition, whatever
+        /// </summary>
+        /// <param name="solution"></param>
+        public void React(Solution solution)
+        {
+            // TODO: Implement metabolism post from here
+            // https://github.com/space-wizards/space-station-14/issues/170#issuecomment-481835623 as raised by moneyl
+            var hungerUpdate = 0;
+            var thirstUpdate = 0;
+            foreach (var reagent in solution.Contents)
+            {
+                switch (reagent.ReagentId)
+                {
+                    case "chem.Nutriment":
+                        hungerUpdate++;
+                        break;
+                    case "chem.H2O":
+                        thirstUpdate++;
+                        break;
+                    case "chem.Alcohol":
+                        thirstUpdate++;
+                        break;
+                    default:
+                        continue;
+                }
+            }
+
+            // Quantity x restore amount per unit
+            if (hungerUpdate > 0 && Owner.TryGetComponent(out HungerComponent hungerComponent))
+            {
+                hungerComponent.UpdateFood(hungerUpdate * NutrimentFactor);
+            }
+
+            if (thirstUpdate > 0 && Owner.TryGetComponent(out ThirstComponent thirstComponent))
+            {
+                thirstComponent.UpdateThirst(thirstUpdate * HydrationFactor);
+            }
+
+            // TODO: Dispose solution?
+        }
+
+        public void Metabolise()
+        {
+            if (_stomachContents.CurrentVolume == 0)
+            {
+                return;
+            }
+
+            var metabolisation = _stomachContents.SplitSolution(MetabolisationAmount);
+
+            React(metabolisation);
+        }
+
+        public void OnUpdate(float frameTime)
+        {
+            _metabolisationCounter += frameTime;
+            if (_metabolisationCounter >= MetaboliseDelay)
+            {
+                // Going to be rounding issues with frametime but no easy way to avoid it with int reagents.
+                // It is a long-term mechanic so shouldn't be a big deal.
+                Metabolise();
+                _metabolisationCounter -= MetaboliseDelay;
+            }
+        }
+    }
+}