Trigger Refactor (#39034)

Content.Shared/Trigger/Systems/DamageOnTriggerSystem.cs

@@ -0,0 +1,40 @@
+using Content.Shared.Damage;
+using Content.Shared.Trigger.Components.Effects;
+
+namespace Content.Shared.Trigger.Systems;
+
+public sealed class DamageOnTriggerSystem : EntitySystem
+{
+    [Dependency] private readonly DamageableSystem _damageableSystem = default!;
+
+    public override void Initialize()
+    {
+        base.Initialize();
+
+        SubscribeLocalEvent<DamageOnTriggerComponent, TriggerEvent>(OnTrigger);
+    }
+
+    private void OnTrigger(Entity<DamageOnTriggerComponent> ent, ref TriggerEvent args)
+    {
+        if (args.Key != null && !ent.Comp.KeysIn.Contains(args.Key))
+            return;
+
+        var target = ent.Comp.TargetUser ? args.User : ent.Owner;
+
+        if (target == null)
+            return;
+
+        var damage = new DamageSpecifier(ent.Comp.Damage);
+        var ev = new BeforeDamageOnTriggerEvent(damage, target.Value);
+        RaiseLocalEvent(ent.Owner, ref ev);
+
+        args.Handled |= _damageableSystem.TryChangeDamage(target, ev.Damage, ent.Comp.IgnoreResistances, origin: ent.Owner) is not null;
+    }
+}
+
+/// <summary>
+/// Raised on an entity before it deals damage using DamageOnTriggerComponent.
+/// Used to modify the damage that will be dealt.
+/// </summary>
+[ByRefEvent]
+public record struct BeforeDamageOnTriggerEvent(DamageSpecifier Damage, EntityUid Tripper);