More xeno artifacts effects (#6282)

Content.Server/Xenoarchaeology/XenoArtifacts/Effects/Systems/GasArtifactSystem.cs

@@ -0,0 +1,57 @@
+using Content.Server.Atmos;
+using Content.Server.Atmos.EntitySystems;
+using Content.Server.Xenoarchaeology.XenoArtifacts.Effects.Components;
+using Content.Server.Xenoarchaeology.XenoArtifacts.Events;
+using Robust.Shared.GameObjects;
+using Robust.Shared.IoC;
+using Robust.Shared.Random;
+
+namespace Content.Server.Xenoarchaeology.XenoArtifacts.Effects.Systems;
+
+public class GasArtifactSystem : EntitySystem
+{
+    [Dependency] private readonly AtmosphereSystem _atmosphereSystem = default!;
+    [Dependency] private readonly IRobustRandom _random = default!;
+
+    public override void Initialize()
+    {
+        base.Initialize();
+        SubscribeLocalEvent<GasArtifactComponent, MapInitEvent>(OnMapInit);
+        SubscribeLocalEvent<GasArtifactComponent, ArtifactActivatedEvent>(OnActivate);
+    }
+
+    private void OnMapInit(EntityUid uid, GasArtifactComponent component, MapInitEvent args)
+    {
+        if (component.SpawnGas == null && component.PossibleGases.Length != 0)
+        {
+            var gas = _random.Pick(component.PossibleGases);
+            component.SpawnGas = gas;
+        }
+
+        if (component.SpawnTemperature == null)
+        {
+            var temp = _random.NextFloat(component.MinRandomTemperature, component.MaxRandomTemperature);
+            component.SpawnTemperature = temp;
+        }
+    }
+
+    private void OnActivate(EntityUid uid, GasArtifactComponent component, ArtifactActivatedEvent args)
+    {
+        if (component.SpawnGas == null || component.SpawnTemperature == null)
+            return;
+
+        var transform = Transform(uid);
+
+        var environment = _atmosphereSystem.GetTileMixture(transform.Coordinates, true);
+        if (environment == null)
+            return;
+
+        if (environment.Pressure >= component.MaxExternalPressure)
+            return;
+
+        var merger = new GasMixture(1) { Temperature = component.SpawnTemperature.Value };
+        merger.SetMoles(component.SpawnGas.Value, component.SpawnAmount);
+
+        _atmosphereSystem.Merge(environment, merger);
+    }
+}