Anomaly Cores (#21306)

* add first anomaly core

* meme

* 5 min to 10 min
fix yml

* fix

* Update doc

* no static price

Content.Server/Anomaly/Effects/AnomalyCoreSystem.cs

@@ -0,0 +1,56 @@
+using Content.Server.Anomaly.Components;
+using Content.Server.Cargo.Systems;
+using Content.Shared.Anomaly;
+using Robust.Shared.Timing;
+
+namespace Content.Server.Anomaly.Effects;
+
+/// <summary>
+/// This component reduces the value of the entity during decay
+/// </summary>
+public sealed class AnomalyCoreSystem : EntitySystem
+{
+    [Dependency] private readonly SharedAppearanceSystem _appearance = default!;
+    [Dependency] private readonly IGameTiming _gameTiming = default!;
+
+    public override void Initialize()
+    {
+        SubscribeLocalEvent<AnomalyCoreComponent, MapInitEvent>(OnMapInit);
+        SubscribeLocalEvent<AnomalyCoreComponent, PriceCalculationEvent>(OnGetPrice);
+    }
+
+    private void OnMapInit(Entity<AnomalyCoreComponent> core, ref MapInitEvent args)
+    {
+        core.Comp.DecayMoment = _gameTiming.CurTime + TimeSpan.FromSeconds(core.Comp.TimeToDecay);
+    }
+
+    public override void Update(float frameTime)
+    {
+        base.Update(frameTime);
+
+        var query = EntityQueryEnumerator<AnomalyCoreComponent>();
+        while (query.MoveNext(out var uid, out var component))
+        {
+            if (component.IsDecayed)
+                continue;
+
+            //When time runs out, we completely decompose
+            if (component.DecayMoment < _gameTiming.CurTime)
+                Decay(uid, component);
+        }
+    }
+    private void OnGetPrice(Entity<AnomalyCoreComponent> core, ref PriceCalculationEvent args)
+    {
+        var timeLeft = core.Comp.DecayMoment - _gameTiming.CurTime;
+        var lerp = (double) (timeLeft.TotalSeconds / core.Comp.TimeToDecay);
+        lerp = Math.Clamp(lerp, 0, 1);
+
+        args.Price = MathHelper.Lerp(core.Comp.EndPrice, core.Comp.StartPrice, lerp);
+    }
+
+    private void Decay(EntityUid uid, AnomalyCoreComponent component)
+    {
+        _appearance.SetData(uid, AnomalyCoreVisuals.Decaying, false);
+        component.IsDecayed = true;
+    }
+}