Fix lasso buckle (#1246)

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

Content.Shared/GameObjects/Components/Mobs/SharedBuckleComponent.cs

@@ -1,13 +1,44 @@
 using System;
+using Content.Shared.GameObjects.EntitySystems;
 using Robust.Shared.GameObjects;
 using Robust.Shared.Serialization;
 
 namespace Content.Shared.GameObjects.Components.Mobs
 {
-    public class SharedBuckleComponent : Component
+    public abstract class SharedBuckleComponent : Component, IActionBlocker, IEffectBlocker
     {
         public sealed override string Name => "Buckle";
 
+        public sealed override uint? NetID => ContentNetIDs.BUCKLE;
+
+        protected abstract bool Buckled { get; }
+
+        bool IActionBlocker.CanMove()
+        {
+            return !Buckled;
+        }
+
+        bool IActionBlocker.CanChangeDirection()
+        {
+            return !Buckled;
+        }
+
+        bool IEffectBlocker.CanFall()
+        {
+            return !Buckled;
+        }
+
+        [Serializable, NetSerializable]
+        protected sealed class BuckleComponentState : ComponentState
+        {
+            public BuckleComponentState(bool buckled) : base(ContentNetIDs.BUCKLE)
+            {
+                Buckled = buckled;
+            }
+
+            public bool Buckled { get; }
+        }
+
         [Serializable, NetSerializable]
         public enum BuckleVisuals
         {

Content.Shared/GameObjects/ContentNetIDs.cs

@@ -56,8 +56,9 @@
         public const uint THIRST = 1050;
 
         public const uint FLASHABLE = 1051;
-        public const uint PROJECTILE = 1052;
-        public const uint THROWN_ITEM = 1053;
+        public const uint BUCKLE = 1052;
+        public const uint PROJECTILE = 1053;
+        public const uint THROWN_ITEM = 1054;
 
         // Net IDs for integration tests.
         public const uint PREDICTION_TEST = 10001;

Content.Shared/GameObjects/EntitySystems/EffectBlockerSystem.cs

@@ -0,0 +1,32 @@
+using Robust.Shared.GameObjects.Systems;
+using Robust.Shared.Interfaces.GameObjects;
+
+namespace Content.Shared.GameObjects.EntitySystems
+{
+    /// <summary>
+    /// This interface gives components the ability to block certain effects
+    /// from affecting the owning entity. For actions see <see cref="IActionBlocker"/>
+    /// </summary>
+    public interface IEffectBlocker
+    {
+        bool CanFall() => true;
+    }
+
+    /// <summary>
+    /// Utility methods to check if an effect is allowed to affect a specific entity.
+    /// For actions see <see cref="ActionBlockerSystem"/>
+    /// </summary>
+    public class EffectBlockerSystem : EntitySystem
+    {
+        public static bool CanFall(IEntity entity)
+        {
+            var canFall = true;
+            foreach (var blocker in entity.GetAllComponents<IEffectBlocker>())
+            {
+                canFall &= blocker.CanFall(); // Sets var to false if false
+            }
+
+            return canFall;
+        }
+    }
+}