Implement magboots. (#2988)

Got an alert and action and everything.

Content.Shared/GameObjects/Components/Inventory/SharedInventoryComponent.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using Content.Shared.GameObjects.Components.Movement;
 using Robust.Shared.GameObjects;
 using Robust.Shared.Interfaces.GameObjects;
 using Robust.Shared.Interfaces.Reflection;
@@ -11,7 +12,7 @@ using static Content.Shared.GameObjects.Components.Inventory.EquipmentSlotDefine
 
 namespace Content.Shared.GameObjects.Components.Inventory
 {
-    public abstract class SharedInventoryComponent : Component
+    public abstract class SharedInventoryComponent : Component, IMoveSpeedModifier
     {
         // ReSharper disable UnassignedReadonlyField
         [Dependency] protected readonly IReflectionManager ReflectionManager;
@@ -100,5 +101,8 @@ namespace Content.Shared.GameObjects.Components.Inventory
                 Slot = slot;
             }
         }
+
+        public abstract float WalkSpeedModifier { get; }
+        public abstract float SprintSpeedModifier { get; }
     }
 }

Content.Shared/GameObjects/Components/Movement/MovementSpeedModifierComponent.cs

@@ -1,4 +1,6 @@
-using Robust.Shared.GameObjects;
+using Robust.Shared.Containers;
+using Robust.Shared.GameObjects;
+using Robust.Shared.Interfaces.GameObjects;
 using Robust.Shared.Serialization;
 using Robust.Shared.ViewVariables;
 
@@ -54,6 +56,15 @@ namespace Content.Shared.GameObjects.Components.Movement
             _movespeedModifiersNeedRefresh = true;
         }
 
+        public static void RefreshItemModifiers(IEntity item)
+        {
+            if (item.TryGetContainer(out var container) &&
+                container.Owner.TryGetComponent(out MovementSpeedModifierComponent mod))
+            {
+                mod.RefreshMovementSpeedModifiers();
+            }
+        }
+
         public override void ExposeData(ObjectSerializer serializer)
         {
             base.ExposeData(serializer);

Content.Shared/GameObjects/Components/SharedMagbootsComponent.cs

@@ -0,0 +1,35 @@
+using System;
+using Content.Shared.GameObjects.Components.Movement;
+using Robust.Shared.GameObjects;
+using Robust.Shared.Serialization;
+
+namespace Content.Shared.GameObjects.Components
+{
+    public abstract class SharedMagbootsComponent : Component, IMoveSpeedModifier
+    {
+        public sealed override string Name => "Magboots";
+        public sealed override uint? NetID => ContentNetIDs.MAGBOOTS;
+
+        public abstract bool On { get; set; }
+
+
+        protected void OnChanged()
+        {
+            MovementSpeedModifierComponent.RefreshItemModifiers(Owner);
+        }
+
+        public float WalkSpeedModifier => On ? 0.85f : 1;
+        public float SprintSpeedModifier => On ? 0.65f : 1;
+
+        [Serializable, NetSerializable]
+        public sealed class MagbootsComponentState : ComponentState
+        {
+            public bool On { get; }
+
+            public MagbootsComponentState(bool @on) : base(ContentNetIDs.MAGBOOTS)
+            {
+                On = on;
+            }
+        }
+    }
+}

Content.Shared/GameObjects/ContentNetIDs.cs

@@ -88,6 +88,7 @@
         public const uint REAGENT_GRINDER = 1082;
         public const uint ACTIONS = 1083;
         public const uint DAMAGEABLE = 1084;
+        public const uint MAGBOOTS = 1085;
 
         // Net IDs for integration tests.
         public const uint PREDICTION_TEST = 10001;