Core - Added ways for the core to easily access brush properties

%*/@ me, dealing with generic types in APIs is tricky

src/Artemis.Core/Models/Profile/LayerProperties/BaseLayerProperty.cs

@@ -1,13 +1,46 @@
-using Artemis.Storage.Entities.Profile;
+using System;
+using System.Collections.Generic;
+using Artemis.Storage.Entities.Profile;
 
 namespace Artemis.Core.Models.Profile.LayerProperties
 {
+    /// <summary>
+    /// For internal use only, to implement your own layer property type, extend <see cref="LayerProperty{T}"/> instead.
+    /// </summary>
     public abstract class BaseLayerProperty
     {
         /// <summary>
         ///     Used to declare that this property doesn't belong to a plugin and should use the core plugin GUID
         /// </summary>
         internal bool IsCoreProperty { get; set; }
+        internal PropertyEntity PropertyEntity { get; set; }
+        internal LayerPropertyGroup LayerPropertyGroup { get; set; }
+
+        /// <summary>
+        ///     Gets whether keyframes are supported on this property
+        /// </summary>
+        public bool KeyframesSupported { get; protected set; }
+
+        /// <summary>
+        ///     Gets or sets whether keyframes are enabled on this property, has no effect if <see cref="KeyframesSupported" /> is
+        ///     False
+        /// </summary>
+        public bool KeyframesEnabled { get; set; }
+
+        /// <summary>
+        ///     Gets or sets whether the property is hidden in the UI
+        /// </summary>
+        public bool IsHidden { get; set; }
+
+        /// <summary>
+        ///     Indicates whether the BaseValue was loaded from storage, useful to check whether a default value must be applied
+        /// </summary>
+        public bool IsLoadedFromStorage { get; internal set; }
+
+        /// <summary>
+        ///     Gets the total progress on the timeline
+        /// </summary>
+        public TimeSpan TimelineProgress { get; internal set; }
 
         /// <summary>
         ///     Applies the provided property entity to the layer property by deserializing the JSON base value and keyframe values
@@ -21,5 +54,8 @@ namespace Artemis.Core.Models.Profile.LayerProperties
         ///     <see cref="ApplyToLayerProperty" />
         /// </summary>
         internal abstract void ApplyToEntity();
+
+        internal abstract List<TimeSpan> GetKeyframePositions();
+        internal abstract TimeSpan GetLastKeyframePosition();
     }
 }

src/Artemis.Core/Models/Profile/LayerProperties/LayerProperty.cs

@@ -53,38 +53,12 @@ namespace Artemis.Core.Models.Profile.LayerProperties
             get => !KeyframesEnabled || !KeyframesSupported ? BaseValue : _currentValue;
             internal set => _currentValue = value;
         }
-
-        /// <summary>
-        ///     Gets whether keyframes are supported on this property
-        /// </summary>
-        public bool KeyframesSupported { get; internal set; }
-
-        /// <summary>
-        ///     Gets or sets whether keyframes are enabled on this property, has no effect if <see cref="KeyframesSupported" /> is
-        ///     False
-        /// </summary>
-        public bool KeyframesEnabled { get; set; }
-
-        /// <summary>
-        ///     Gets or sets whether the property is hidden in the UI
-        /// </summary>
-        public bool IsHidden { get; set; }
-
-        /// <summary>
-        ///     Indicates whether the BaseValue was loaded from storage, useful to check whether a default value must be applied
-        /// </summary>
-        public bool IsLoadedFromStorage { get; internal set; }
-
+        
         /// <summary>
         ///     Gets a read-only list of all the keyframes on this layer property
         /// </summary>
         public IReadOnlyList<LayerPropertyKeyframe<T>> Keyframes => _keyframes.AsReadOnly();
-
-        /// <summary>
-        ///     Gets the total progress on the timeline
-        /// </summary>
-        public TimeSpan TimelineProgress { get; private set; }
-
+        
         /// <summary>
         ///     Gets the current keyframe in the timeline according to the current progress
         /// </summary>
@@ -94,10 +68,7 @@ namespace Artemis.Core.Models.Profile.LayerProperties
         ///     Gets the next keyframe in the timeline according to the current progress
         /// </summary>
         public LayerPropertyKeyframe<T> NextKeyframe { get; protected set; }
-
-        internal PropertyEntity PropertyEntity { get; set; }
-        internal LayerPropertyGroup LayerPropertyGroup { get; set; }
-
+        
         /// <summary>
         ///     Adds a keyframe to the layer property
         /// </summary>
@@ -232,6 +203,16 @@ namespace Artemis.Core.Models.Profile.LayerProperties
             }));
         }
 
+        internal override List<TimeSpan> GetKeyframePositions()
+        {
+            return Keyframes.Select(k => k.Position).ToList();
+        }
+
+        internal override TimeSpan GetLastKeyframePosition()
+        {
+            return Keyframes.LastOrDefault()?.Position ?? TimeSpan.Zero;
+        }
+
         #region Events
 
         public event EventHandler Updated;

src/Artemis.Core/Models/Profile/LayerProperties/Types/EnumLayerProperty.cs

@@ -1,9 +1,10 @@
-using Artemis.Core.Exceptions;
+using System;
+using Artemis.Core.Exceptions;
 
 namespace Artemis.Core.Models.Profile.LayerProperties.Types
 {
-    /// <inheritdoc/>
-    public class EnumLayerProperty<T> : LayerProperty<T> where T : System.Enum
+    /// <inheritdoc />
+    public class EnumLayerProperty<T> : LayerProperty<T> where T : Enum
     {
         public EnumLayerProperty()
         {