Add emp grenade (#14393)

Content.Server/Emp/EmpSystem.cs

@@ -0,0 +1,39 @@
+using Content.Server.Explosion.EntitySystems;
+using Robust.Shared.Map;
+
+namespace Content.Server.Emp;
+
+public sealed class EmpSystem : EntitySystem
+{
+    [Dependency] private readonly EntityLookupSystem _lookup = default!;
+
+    public const string EmpPulseEffectPrototype = "EffectEmpPulse";
+    public const string EmpDisabledEffectPrototype = "EffectEmpDisabled";
+
+    public override void Initialize()
+    {
+        base.Initialize();
+        SubscribeLocalEvent<EmpOnTriggerComponent, TriggerEvent>(HandleEmpTrigger);
+    }
+
+    public void EmpPulse(MapCoordinates coordinates, float range, float energyConsumption)
+    {
+        foreach (var uid in _lookup.GetEntitiesInRange(coordinates, range))
+        {
+            var ev = new EmpPulseEvent(energyConsumption, false);
+            RaiseLocalEvent(uid, ref ev);
+            if (ev.Affected)
+                Spawn(EmpDisabledEffectPrototype, Transform(uid).Coordinates);
+        }
+        Spawn(EmpPulseEffectPrototype, coordinates);
+    }
+
+    private void HandleEmpTrigger(EntityUid uid, EmpOnTriggerComponent comp, TriggerEvent args)
+    {
+        EmpPulse(Transform(uid).Coordinates.ToMap(EntityManager), comp.Range, comp.EnergyConsumption);
+        args.Handled = true;
+    }
+}
+
+[ByRefEvent]
+public record struct EmpPulseEvent(float EnergyConsumption, bool Affected);