Simplify Tower (C#) folder structure

90_Tower/csharp/UI/Prompt.cs

@@ -0,0 +1,41 @@
+using System.Collections.Generic;
+using System.Linq;
+using static Tower.Resources.Strings;
+
+namespace Tower.UI
+{
+    internal class Prompt
+    {
+        public static Prompt DiskCount =
+            new(DiskCountPrompt, DiskCountRetry, DiskCountQuit, 1, 2, 3, 4, 5, 6, 7) { RetriesAllowed = 2 };
+
+        public static Prompt Disk =
+            new(DiskPrompt, DiskRetry, DiskQuit, 3, 5, 7, 9, 11, 13, 15) { RepeatPrompt = false };
+
+        public static Prompt Needle = new(NeedlePrompt, NeedleRetry, NeedleQuit, 1, 2, 3);
+
+        private readonly HashSet<int> _validValues;
+
+        private Prompt(string prompt, string retryMessage, string quitMessage, params int[] validValues)
+        {
+            Message = prompt;
+            RetryMessage = retryMessage;
+            QuitMessage = quitMessage;
+            _validValues = validValues.ToHashSet();
+            RetriesAllowed = 1;
+            RepeatPrompt = true;
+        }
+
+        public string Message { get; }
+        public string RetryMessage { get; }
+        public string QuitMessage { get; }
+        public int RetriesAllowed { get; private set; }
+        public bool RepeatPrompt { get; private set; }
+
+        public bool TryValidateResponse(float number, out int integer)
+        {
+            integer = (int)number;
+            return integer == number && _validValues.Contains(integer);
+        }
+    }
+}