add color to server

server/Lib.cs

@@ -1,3 +1,4 @@
+using System.Text.RegularExpressions;
 using SpacetimeDB;
 
 public static partial class Module
@@ -8,6 +9,7 @@ public static partial class Module
         [PrimaryKey]
         public Identity Identity;
         public string? Name;
+        public string? Color;
         public bool Online;
     }
 
@@ -42,6 +44,31 @@ public static partial class Module
         return name;
     }
 
+    [Reducer]
+    public static void SetColor(ReducerContext ctx, string color)
+    {
+        color = ValidateColor(color);
+
+        var user = ctx.Db.User.Identity.Find(ctx.Sender);
+
+        if (user is null)
+        {
+            return;
+        }
+        user.Color = color;
+        ctx.Db.User.Identity.Update(user);
+    }
+
+    private static string ValidateColor(string color)
+    {
+        var regex = new Regex("^#([A-Fa-f0-9]{6}|[A-Fa-f0-9]{3})$");
+        if (regex.IsMatch(color))
+        {
+            throw new Exception("Invalid color code");
+        }
+        return color;
+    }
+
     [Reducer]
     public static void SendMessage(ReducerContext ctx, string text)
     {
@@ -113,4 +140,3 @@ public static partial class Module
         }
     }
 }
-