Use "smart references" for member commands

PluralKit.Bot/Utils/ModelUtils.cs

@@ -1,4 +1,7 @@
-using PluralKit.Core;
+using System.Linq;
+using System.Text.RegularExpressions;
+
+using PluralKit.Core;
 
 namespace PluralKit.Bot
 {
@@ -12,5 +15,32 @@ namespace PluralKit.Bot
 
         public static string DisplayName(this PKMember member) =>
             member.DisplayName ?? member.Name;
+
+        public static string Reference(this PKMember member) => EntityReference(member.Hid, member.Name);
+        public static string Reference(this PKGroup group) => EntityReference(group.Hid, group.Name);
+
+        private static string EntityReference(string hid, string name)
+        {
+            bool IsSimple(string s) =>
+                // No spaces, no symbols, allow single quote but not at the start
+                Regex.IsMatch(s, "^[\\w\\d\\-_'?]+$") && !s.StartsWith("'");
+            
+            // If it's very long (>25 chars), always use hid
+            if (name.Length >= 25)
+                return hid;
+
+            // If name is "simple" just use that
+            if (IsSimple(name)) 
+                return name;
+            
+            // If three or fewer "words" and they're all simple individually, quote them
+            var words = name.Split(' ');
+            if (words.Length <= 3 && words.All(w => w.Length > 0 && IsSimple(w)))
+                // Words with double quotes are never "simple" so we're safe to naive-quote here
+                return $"\"{name}\"";
+            
+            // Otherwise, just use hid
+            return hid;
+        }
     }
 }