Add gas selling to tanks too (#11304)

Content.Server/Atmos/EntitySystems/AtmosphereSystem.Utils.cs

@@ -8,6 +8,30 @@ namespace Content.Server.Atmos.EntitySystems;
 
 public partial class AtmosphereSystem
 {
+    /// <summary>
+    /// Gets the particular price of an air mixture.
+    /// </summary>
+    public double GetPrice(GasMixture mixture)
+    {
+        float basePrice = 0; // moles of gas * price/mole
+        float totalMoles = 0; // total number of moles in can
+        float maxComponent = 0; // moles of the dominant gas
+        for (var i = 0; i < Atmospherics.TotalNumberOfGases; i++)
+        {
+            basePrice += mixture.Moles[i] * GetGas(i).PricePerMole;
+            totalMoles += mixture.Moles[i];
+            maxComponent = Math.Max(maxComponent, mixture.Moles[i]);
+        }
+
+        // Pay more for gas canisters that are more pure
+        float purity = 1;
+        if (totalMoles > 0) {
+            purity = maxComponent / totalMoles;
+        }
+
+        return basePrice * purity;
+    }
+
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public void InvalidateVisuals(EntityUid gridUid, Vector2i tile)
     {

Content.Server/Atmos/EntitySystems/GasTankSystem.cs

@@ -1,16 +1,15 @@
 using Content.Server.Atmos.Components;
 using Content.Server.Body.Components;
 using Content.Server.Body.Systems;
+using Content.Server.Cargo.Systems;
 using Content.Server.Explosion.EntitySystems;
 using Content.Server.UserInterface;
 using Content.Shared.Actions;
 using Content.Shared.Atmos;
 using Content.Shared.Atmos.Components;
 using Content.Shared.Audio;
-using Content.Shared.Interaction.Events;
 using Content.Shared.Toggleable;
 using Content.Shared.Examine;
-using Content.Shared.Inventory;
 using JetBrains.Annotations;
 using Robust.Server.GameObjects;
 using Robust.Server.Player;
@@ -45,6 +44,7 @@ namespace Content.Server.Atmos.EntitySystems
             SubscribeLocalEvent<GasTankComponent, GasTankSetPressureMessage>(OnGasTankSetPressure);
             SubscribeLocalEvent<GasTankComponent, GasTankToggleInternalsMessage>(OnGasTankToggleInternals);
             SubscribeLocalEvent<GasTankComponent, GasAnalyzerScanEvent>(OnAnalyzed);
+            SubscribeLocalEvent<GasTankComponent, PriceCalculationEvent>(OnGasTankPrice);
         }
 
         private void OnGasShutdown(EntityUid uid, GasTankComponent component, ComponentShutdown args)
@@ -332,5 +332,10 @@ namespace Content.Server.Atmos.EntitySystems
         {
             args.GasMixtures = new Dictionary<string, GasMixture?> { {Name(uid), component.Air} };
         }
+
+        private void OnGasTankPrice(EntityUid uid, GasTankComponent component, ref PriceCalculationEvent args)
+        {
+            args.Price += _atmosphereSystem.GetPrice(component.Air);
+        }
     }
 }

Content.Server/Atmos/Piping/Unary/EntitySystems/GasCanisterSystem.cs

@@ -298,22 +298,7 @@ namespace Content.Server.Atmos.Piping.Unary.EntitySystems
 
         private void CalculateCanisterPrice(EntityUid uid, GasCanisterComponent component, ref PriceCalculationEvent args)
         {
-            float basePrice = 0; // moles of gas * price/mole
+            args.Price += _atmosphereSystem.GetPrice(component.Air);
-            float totalMoles = 0; // total number of moles in can
-            float maxComponent = 0; // moles of the dominant gas
-            for (var i = 0; i < Atmospherics.TotalNumberOfGases; i++)
-            {
-                basePrice += component.Air.Moles[i] * _atmosphereSystem.GetGas(i).PricePerMole;
-                totalMoles += component.Air.Moles[i];
-                maxComponent = Math.Max(maxComponent, component.Air.Moles[i]);
-            }
-
-            // Pay more for gas canisters that are more pure
-            float purity = 1;
-            if (totalMoles > 0) {
-                purity = maxComponent / totalMoles;
-            }
-            args.Price += basePrice * purity;
         }
 
         /// <summary>