Add back pull moving (#3635)

* Add back pull moving

* Make pull moving event-based, use map coordinates, slow down moving when getting closer and stop moving when very close, add max range and add compensation for overshooting

* Remove compensation

* Prevent pull move from pulling you

* acruid did this

* Add unsubscriptions to shutdown

Co-authored-by: metalgearsloth <comedian_vs_clown@hotmail.com>

Content.Server/Physics/Controllers/PullController.cs

@@ -0,0 +1,78 @@
+#nullable enable
+using System;
+using System.Collections.Generic;
+using Content.Shared.GameObjects.EntitySystems;
+using Robust.Shared.GameObjects;
+using Robust.Shared.Physics;
+using Robust.Shared.Physics.Controllers;
+using Robust.Shared.Utility;
+
+namespace Content.Server.Physics.Controllers
+{
+    public class PullController : VirtualController
+    {
+        private const int ImpulseModifier = 20;
+
+        private SharedPullingSystem _pullableSystem = default!;
+
+        public override List<Type> UpdatesAfter => new() {typeof(MoverController)};
+
+        public override void Initialize()
+        {
+            base.Initialize();
+
+            _pullableSystem = EntitySystem.Get<SharedPullingSystem>();
+        }
+
+        public override void UpdateBeforeSolve(bool prediction, float frameTime)
+        {
+            base.UpdateBeforeSolve(prediction, frameTime);
+
+            foreach (var pullable in _pullableSystem.Moving)
+            {
+                if (pullable.Deleted)
+                {
+                    continue;
+                }
+
+                if (pullable.MovingTo == null)
+                {
+                    continue;
+                }
+
+                DebugTools.AssertNotNull(pullable.Puller);
+
+                var pullerPosition = pullable.Puller!.Transform.MapPosition;
+                if (pullable.MovingTo.Value.MapId != pullerPosition.MapId)
+                {
+                    pullable.MovingTo = null;
+                    continue;
+                }
+
+                if (!pullable.Owner.TryGetComponent<PhysicsComponent>(out var physics) ||
+                    physics.BodyType == BodyType.Static ||
+                    pullable.MovingTo.Value.MapId != pullable.Owner.Transform.MapID)
+                {
+                    pullable.MovingTo = null;
+                    continue;
+                }
+
+                var movingPosition = pullable.MovingTo.Value.Position;
+                var ownerPosition = pullable.Owner.Transform.MapPosition.Position;
+
+                if (movingPosition.EqualsApprox(ownerPosition, 0.01))
+                {
+                    pullable.MovingTo = null;
+                    continue;
+                }
+
+                var diff = movingPosition - ownerPosition;
+                var diffLength = diff.Length;
+                var multiplier = diffLength < 1 ? ImpulseModifier * diffLength : ImpulseModifier;
+                var impulse = diff.Normalized * multiplier;
+
+                physics.ApplyLinearImpulse(impulse);
+            }
+        }
+    }
+}