write XNA input enums to JSON as strings automatically

Mods often reference Json.NET to do this, so this lets many mods remove Json.NET as a dependency.

3 files changed, 43 insertions, 1 deletions

diff --git a/src/StardewModdingAPI/Framework/Serialisation/JsonHelper.cs b/src/StardewModdingAPI/Framework/Serialisation/JsonHelper.cs
index 26d937a5..d5f5bfd0 100644
--- a/src/StardewModdingAPI/Framework/Serialisation/JsonHelper.cs
+++ b/src/StardewModdingAPI/Framework/Serialisation/JsonHelper.cs
@@ -1,5 +1,7 @@
 using System;
+using System.Collections.Generic;
 using System.IO;
+using Microsoft.Xna.Framework.Input;
 using Newtonsoft.Json;
 using StardewModdingAPI.Advanced;
 
@@ -15,7 +17,11 @@ namespace StardewModdingAPI.Framework.Serialisation
         private readonly JsonSerializerSettings JsonSettings = new JsonSerializerSettings
         {
             Formatting = Formatting.Indented,
-            ObjectCreationHandling = ObjectCreationHandling.Replace // avoid issue where default ICollection<T> values are duplicated each time the config is loaded
+            ObjectCreationHandling = ObjectCreationHandling.Replace, // avoid issue where default ICollection<T> values are duplicated each time the config is loaded
+            Converters = new List<JsonConverter>
+            {
+                new SelectiveStringEnumConverter(typeof(Buttons), typeof(Keys))
+            }
         };
 
 
diff --git a/src/StardewModdingAPI/Framework/Serialisation/SelectiveStringEnumConverter.cs b/src/StardewModdingAPI/Framework/Serialisation/SelectiveStringEnumConverter.cs
new file mode 100644
index 00000000..e9c5496d
--- /dev/null
+++ b/src/StardewModdingAPI/Framework/Serialisation/SelectiveStringEnumConverter.cs
@@ -0,0 +1,35 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using Newtonsoft.Json.Converters;
+
+namespace StardewModdingAPI.Framework.Serialisation
+{
+    /// <summary>A variant of <see cref="StringEnumConverter"/> which only converts certain enums.</summary>
+    internal class SelectiveStringEnumConverter : StringEnumConverter
+    {
+        /*********
+        ** Properties
+        *********/
+        /// <summary>The enum type names to convert.</summary>
+        private readonly HashSet<string> Types;
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="types">The enum types to convert.</param>
+        public SelectiveStringEnumConverter(params Type[] types)
+        {
+            this.Types = new HashSet<string>(types.Select(p => p.FullName));
+        }
+
+        /// <summary>Get whether this instance can convert the specified object type.</summary>
+        /// <param name="type">The object type.</param>
+        public override bool CanConvert(Type type)
+        {
+            return base.CanConvert(type) && this.Types.Contains(type.FullName);
+        }
+    }
+}
diff --git a/src/StardewModdingAPI/StardewModdingAPI.csproj b/src/StardewModdingAPI/StardewModdingAPI.csproj
index 35dd6513..796980cb 100644
--- a/src/StardewModdingAPI/StardewModdingAPI.csproj
+++ b/src/StardewModdingAPI/StardewModdingAPI.csproj
@@ -153,6 +153,7 @@
     <Compile Include="Framework\Reflection\PrivateProperty.cs" />
     <Compile Include="Framework\RequestExitDelegate.cs" />
     <Compile Include="Framework\Serialisation\JsonHelper.cs" />
+    <Compile Include="Framework\Serialisation\SelectiveStringEnumConverter.cs" />
     <Compile Include="Framework\Serialisation\SemanticVersionConverter.cs" />
     <Compile Include="ICommandHelper.cs" />
     <Compile Include="IModRegistry.cs" />