Mirror speed penalty for worn duffels and hardsuits when in-hand (#22168)

* Add speed penalty for holding hardsuits and duffels

* just inherit from ClothingSpeedModifier

* comment godo

Content.Shared/Item/HeldSpeedModifierSystem.cs

@@ -0,0 +1,44 @@
+using Content.Shared.Clothing;
+using Content.Shared.Hands;
+using Content.Shared.Movement.Systems;
+
+namespace Content.Shared.Item;
+
+/// <summary>
+/// This handles <see cref="HeldSpeedModifierComponent"/>
+/// </summary>
+public sealed class HeldSpeedModifierSystem : EntitySystem
+{
+    [Dependency] private readonly MovementSpeedModifierSystem _movementSpeedModifier = default!;
+
+    /// <inheritdoc/>
+    public override void Initialize()
+    {
+        SubscribeLocalEvent<HeldSpeedModifierComponent, GotEquippedHandEvent>(OnGotEquippedHand);
+        SubscribeLocalEvent<HeldSpeedModifierComponent, GotUnequippedHandEvent>(OnGotUnequippedHand);
+        SubscribeLocalEvent<HeldSpeedModifierComponent, HeldRelayedEvent<RefreshMovementSpeedModifiersEvent>>(OnRefreshMovementSpeedModifiers);
+    }
+
+    private void OnGotEquippedHand(Entity<HeldSpeedModifierComponent> ent, ref GotEquippedHandEvent args)
+    {
+        _movementSpeedModifier.RefreshMovementSpeedModifiers(args.User);
+    }
+
+    private void OnGotUnequippedHand(Entity<HeldSpeedModifierComponent> ent, ref GotUnequippedHandEvent args)
+    {
+        _movementSpeedModifier.RefreshMovementSpeedModifiers(args.User);
+    }
+
+    private void OnRefreshMovementSpeedModifiers(EntityUid uid, HeldSpeedModifierComponent component, HeldRelayedEvent<RefreshMovementSpeedModifiersEvent> args)
+    {
+        var walkMod = component.WalkModifier;
+        var sprintMod = component.SprintModifier;
+        if (component.MirrorClothingModifier && TryComp<ClothingSpeedModifierComponent>(uid, out var clothingSpeedModifier))
+        {
+            walkMod = clothingSpeedModifier.WalkModifier;
+            sprintMod = clothingSpeedModifier.SprintModifier;
+        }
+
+        args.Args.ModifySpeed(walkMod, sprintMod);
+    }
+}