Port boxer from Nyano (#9080)

Content.Server/Abilities/Boxer/Boxer/BoxerComponent.cs

@@ -0,0 +1,23 @@
+using Content.Shared.Damage;
+
+namespace Content.Server.Abilities.Boxer
+{
+    /// <summary>
+    /// Added to the boxer on spawn.
+    /// </summary>
+    [RegisterComponent]
+    public sealed class BoxerComponent : Component
+    {
+        [DataField("modifiers", required: true)]
+        public DamageModifierSet UnarmedModifiers = default!;
+
+        [DataField("rangeBonus")]
+        public float RangeBonus = 1.5f;
+
+        /// <summary>
+        /// Damage modifier with boxing glove stam damage.
+        /// </summary>
+        [DataField("boxingGlovesModifier")]
+        public float BoxingGlovesModifier = 1.75f;
+    }
+}

Content.Server/Abilities/Boxer/Boxer/BoxingGlovesComponent.cs

@@ -0,0 +1,11 @@
+using Content.Shared.Damage;
+
+namespace Content.Server.Abilities.Boxer
+{
+    /// <summary>
+    /// Boxer gets a bonus for these, and their fists, but not other unarmed weapons.
+    /// </summary>
+    [RegisterComponent]
+    public sealed class BoxingGlovesComponent : Component
+    {}
+}

Content.Server/Abilities/Boxer/BoxingSystem.cs

@@ -0,0 +1,51 @@
+using Content.Server.Weapon.Melee;
+using Content.Server.Stunnable;
+using Content.Shared.Inventory.Events;
+using Content.Server.Weapon.Melee.Components;
+using Content.Server.Clothing.Components;
+using Content.Server.Damage.Components;
+using Content.Server.Damage.Events;
+using Robust.Shared.Audio;
+using Robust.Shared.Player;
+using Robust.Shared.Random;
+using Robust.Shared.Containers;
+
+namespace Content.Server.Abilities.Boxer
+{
+    public sealed class BoxingSystem : EntitySystem
+    {
+        [Dependency] private readonly StunSystem _stunSystem = default!;
+        [Dependency] private readonly IRobustRandom _robustRandom = default!;
+        [Dependency] private readonly SharedContainerSystem _containerSystem = default!;
+
+        public override void Initialize()
+        {
+            base.Initialize();
+            SubscribeLocalEvent<BoxerComponent, ComponentInit>(OnInit);
+            SubscribeLocalEvent<BoxerComponent, MeleeHitEvent>(ApplyBoxerModifiers);
+            SubscribeLocalEvent<BoxingGlovesComponent, StaminaMeleeHitEvent>(OnStamHit);
+        }
+
+        private void OnInit(EntityUid uid, BoxerComponent boxer, ComponentInit args)
+        {
+            if (TryComp<MeleeWeaponComponent>(uid, out var meleeComp))
+                meleeComp.Range *= boxer.RangeBonus;
+        }
+        private void ApplyBoxerModifiers(EntityUid uid, BoxerComponent component, MeleeHitEvent args)
+        {
+            if (component.UnarmedModifiers == default!)
+            {
+                Logger.Warning("BoxerComponent on " + uid + " couldn't get damage modifiers. Know that adding components with damage modifiers through VV or similar is unsupported.");
+                return;
+            }
+
+            args.ModifiersList.Add(component.UnarmedModifiers);
+        }
+        private void OnStamHit(EntityUid uid, BoxingGlovesComponent component, StaminaMeleeHitEvent args)
+        {
+            _containerSystem.TryGetContainingContainer(uid, out var equipee);
+            if (TryComp<BoxerComponent>(equipee?.Owner, out var boxer))
+                args.Multiplier *= boxer.BoxingGlovesModifier;
+        }
+    }
+}