Hot potato on fire (#16017)

Content.Shared/Damage/Systems/DamageOnHoldingSystem.cs

@@ -0,0 +1,53 @@
+using Content.Shared.Damage.Components;
+using Robust.Shared.Containers;
+using Robust.Shared.Timing;
+
+namespace Content.Shared.Damage.Systems;
+
+public sealed class DamageOnHoldingSystem : EntitySystem
+{
+    [Dependency] private readonly SharedContainerSystem _container = default!;
+    [Dependency] private readonly DamageableSystem _damageableSystem = default!;
+    [Dependency] private readonly IGameTiming _timing = default!;
+
+    public override void Initialize()
+    {
+        base.Initialize();
+        SubscribeLocalEvent<DamageOnHoldingComponent, EntityUnpausedEvent>(OnUnpaused);
+        SubscribeLocalEvent<DamageOnHoldingComponent, MapInitEvent>(OnMapInit);
+    }
+
+    public void SetEnabled(EntityUid uid, bool enabled, DamageOnHoldingComponent? component = null)
+    {
+        if (Resolve(uid, ref component))
+        {
+            component.Enabled = enabled;
+            component.NextDamage = _timing.CurTime;
+        }
+    }
+
+    private void OnUnpaused(EntityUid uid, DamageOnHoldingComponent component, ref EntityUnpausedEvent args)
+    {
+        component.NextDamage += args.PausedTime;
+    }
+
+    private void OnMapInit(EntityUid uid, DamageOnHoldingComponent component, MapInitEvent args)
+    {
+        component.NextDamage = _timing.CurTime;
+    }
+
+    public override void Update(float frameTime)
+    {
+        var query = EntityQueryEnumerator<DamageOnHoldingComponent>();
+        while (query.MoveNext(out var uid, out var component))
+        {
+            if (!component.Enabled || component.NextDamage > _timing.CurTime)
+                continue;
+            if (_container.TryGetContainingContainer(uid, out var container))
+            {
+                _damageableSystem.TryChangeDamage(container.Owner, component.Damage, origin: uid);
+            }
+            component.NextDamage = _timing.CurTime + TimeSpan.FromSeconds(component.Interval);
+        }
+    }
+}