1 files changed, 81 insertions, 0 deletions
diff --git a/src/Ryujinx.Common/Configuration/Hid/JsonInputConfigConverter.cs b/src/Ryujinx.Common/Configuration/Hid/JsonInputConfigConverter.cs
new file mode 100644
index 00000000..08bbcbf1
--- /dev/null
+++ b/src/Ryujinx.Common/Configuration/Hid/JsonInputConfigConverter.cs
@@ -0,0 +1,81 @@
+using Ryujinx.Common.Configuration.Hid.Controller;
+using Ryujinx.Common.Configuration.Hid.Keyboard;
+using Ryujinx.Common.Utilities;
+using System;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace Ryujinx.Common.Configuration.Hid
+{
+    public class JsonInputConfigConverter : JsonConverter<InputConfig>
+    {
+        private static readonly InputConfigJsonSerializerContext SerializerContext = new(JsonHelper.GetDefaultSerializerOptions());
+
+        private static InputBackendType GetInputBackendType(ref Utf8JsonReader reader)
+        {
+            // Temporary reader to get the backend type
+            Utf8JsonReader tempReader = reader;
+
+            InputBackendType result = InputBackendType.Invalid;
+
+            while (tempReader.Read())
+            {
+                // NOTE: We scan all properties ignoring the depth entirely on purpose.
+                // The reason behind this is that we cannot track in a reliable way the depth of the object because Utf8JsonReader never emit the first TokenType == StartObject if the json start with an object.
+                // As such, this code will try to parse very field named "backend" to the correct enum.
+                if (tempReader.TokenType == JsonTokenType.PropertyName)
+                {
+                    string propertyName = tempReader.GetString();
+
+                    if (propertyName.Equals("backend"))
+                    {
+                        tempReader.Read();
+
+                        if (tempReader.TokenType == JsonTokenType.String)
+                        {
+                            string backendTypeRaw = tempReader.GetString();
+
+                            if (!Enum.TryParse(backendTypeRaw, out result))
+                            {
+                                result = InputBackendType.Invalid;
+                            }
+                            else
+                            {
+                                break;
+                            }
+                        }
+                    }
+                }
+            }
+
+            return result;
+        }
+
+        public override InputConfig Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+        {
+            InputBackendType backendType = GetInputBackendType(ref reader);
+
+            return backendType switch
+            {
+                InputBackendType.WindowKeyboard => JsonSerializer.Deserialize(ref reader, SerializerContext.StandardKeyboardInputConfig),
+                InputBackendType.GamepadSDL2 => JsonSerializer.Deserialize(ref reader, SerializerContext.StandardControllerInputConfig),
+                _ => throw new InvalidOperationException($"Unknown backend type {backendType}"),
+            };
+        }
+
+        public override void Write(Utf8JsonWriter writer, InputConfig value, JsonSerializerOptions options)
+        {
+            switch (value.Backend)
+            {
+                case InputBackendType.WindowKeyboard:
+                    JsonSerializer.Serialize(writer, value as StandardKeyboardInputConfig, SerializerContext.StandardKeyboardInputConfig);
+                    break;
+                case InputBackendType.GamepadSDL2:
+                    JsonSerializer.Serialize(writer, value as StandardControllerInputConfig, SerializerContext.StandardControllerInputConfig);
+                    break;
+                default:
+                    throw new ArgumentException($"Unknown backend type {value.Backend}");
+            }
+        }
+    }
+}