Add utility AI (#806)

Co-authored-by: Pieter-Jan Briers <pieterjan.briers@gmail.com>
Co-authored-by: Metal Gear Sloth <metalgearsloth@gmail.com>
Co-authored-by: Pieter-Jan Briers <pieterjan.briers+git@gmail.com>

Content.Server/AI/Operators/Combat/SwingMeleeWeaponOperator.cs

@@ -0,0 +1,74 @@
+using Content.Server.GameObjects;
+using Content.Server.GameObjects.Components.Mobs;
+using Content.Server.GameObjects.Components.Weapon.Melee;
+using Content.Server.GameObjects.EntitySystems;
+using Robust.Shared.Interfaces.GameObjects;
+using Robust.Shared.IoC;
+
+namespace Content.Server.AI.Operators.Combat
+{
+    public class SwingMeleeWeaponOperator : AiOperator
+    {
+        private float _burstTime;
+        private float _elapsedTime;
+
+        private readonly IEntity _owner;
+        private readonly IEntity _target;
+
+        public SwingMeleeWeaponOperator(IEntity owner, IEntity target, float burstTime = 1.0f)
+        {
+            _owner = owner;
+            _target = target;
+            _burstTime = burstTime;
+        }
+
+        public override bool TryStartup()
+        {
+            if (!base.TryStartup())
+            {
+                return true;
+            }
+            
+            if (!_owner.TryGetComponent(out CombatModeComponent combatModeComponent))
+            {
+                return false;
+            }
+
+            if (!combatModeComponent.IsInCombatMode)
+            {
+                combatModeComponent.IsInCombatMode = true;
+            }
+
+            return true;
+        }
+
+        public override Outcome Execute(float frameTime)
+        {
+            if (_burstTime <= _elapsedTime)
+            {
+                return Outcome.Success;
+            }
+
+            if (!_owner.TryGetComponent(out HandsComponent hands) || hands.GetActiveHand == null)
+            {
+                return Outcome.Failed;
+            }
+
+            var meleeWeapon = hands.GetActiveHand.Owner;
+            meleeWeapon.TryGetComponent(out MeleeWeaponComponent meleeWeaponComponent);
+
+            if ((_target.Transform.GridPosition.Position - _owner.Transform.GridPosition.Position).Length >
+                meleeWeaponComponent.Range)
+            {
+                return Outcome.Failed;
+            }
+
+            var interactionSystem = IoCManager.Resolve<IEntitySystemManager>().GetEntitySystem<InteractionSystem>();
+
+            interactionSystem.UseItemInHand(_owner, _target.Transform.GridPosition, _target.Uid);
+            _elapsedTime += frameTime;
+            return Outcome.Continuing;
+        }
+    }
+
+}