first commit

Data/Song/Chart.cs

@@ -0,0 +1,25 @@
+using System;
+
+namespace MercuryConverter.Data;
+
+
+public class Chart
+{
+    public required string audioId;
+    public required string audioOffset;
+    public required string audioPreviewTime;
+    public required string audioPreviewDuration;
+    public required string video;
+    public required string designer;
+    public required string clearRequirement;
+    public required string diffLevel;
+    public string diffString
+    {
+        get
+        {
+            var d = Convert.ToDouble(diffLevel);
+            var i = (int)d;
+            return $"{(int)d}{(d > i ? "+" : "")}";
+        }
+    }
+}