Simplify Mastermind (C#) folder structure

60_Mastermind/csharp/Controller.cs

@@ -0,0 +1,175 @@
+using System;
+using System.Collections.Immutable;
+using System.Linq;
+
+namespace Game
+{
+    /// <summary>
+    /// Contains functions for getting input from the end user.
+    /// </summary>
+    public static class Controller
+    {
+        /// <summary>
+        /// Maps the letters for each color to the integer value representing
+        /// that color.
+        /// </summary>
+        /// <remarks>
+        /// We derive this map from the Colors list rather than defining the
+        /// entries directly in order to keep all color related information
+        /// in one place.  (This makes it easier to change the color options
+        /// later.)
+        /// </remarks>
+        private static ImmutableDictionary<char, int> ColorsByKey = Colors.List
+            .Select((info, index) => (key: info.ShortName, index))
+            .ToImmutableDictionary(entry => entry.key, entry => entry.index);
+
+        /// <summary>
+        /// Gets the number of colors to use in the secret code.
+        /// </summary>
+        public static int GetNumberOfColors()
+        {
+            var maximumColors = Colors.List.Length;
+            var colors = 0;
+
+            while (colors < 1 || colors > maximumColors)
+            {
+                colors = GetInteger(View.PromptNumberOfColors);
+                if (colors > maximumColors)
+                    View.NotifyTooManyColors(maximumColors);
+            }
+
+            return colors;
+        }
+
+        /// <summary>
+        /// Gets the number of positions in the secret code.
+        /// </summary>
+        /// <returns></returns>
+        public static int GetNumberOfPositions()
+        {
+            // Note: We should probably ensure that the user enters a sane
+            //  number of positions here.  (Things go south pretty quickly
+            //  with a large number of positions.)  But since the original
+            //  program did not, neither will we.
+            return GetInteger(View.PromptNumberOfPositions);
+        }
+
+        /// <summary>
+        /// Gets the number of rounds to play.
+        /// </summary>
+        public static int GetNumberOfRounds()
+        {
+            // Note: Silly numbers of rounds (like 0, or a negative number)
+            //  are harmless, but it would still make sense to validate.
+            return GetInteger(View.PromptNumberOfRounds);
+        }
+
+        /// <summary>
+        /// Gets a command from the user.
+        /// </summary>
+        /// <param name="moveNumber">
+        /// The current move number.
+        /// </param>
+        /// <param name="positions">
+        /// The number of code positions.
+        /// </param>
+        /// <param name="colors">
+        /// The maximum number of code colors.
+        /// </param>
+        /// <returns>
+        /// The entered command and guess (if applicable).
+        /// </returns>
+        public static (Command command, Code? guess) GetCommand(int moveNumber, int positions, int colors)
+        {
+            while (true)
+            {
+                View.PromptGuess (moveNumber);
+
+                var input = Console.ReadLine();
+                if (input is null)
+                    Environment.Exit(0);
+
+                switch (input.ToUpperInvariant())
+                {
+                    case "BOARD":
+                        return (Command.ShowBoard, null);
+                    case "QUIT":
+                        return (Command.Quit, null);
+                    default:
+                        if (input.Length != positions)
+                            View.NotifyBadNumberOfPositions();
+                        else
+                        if (input.FindFirstIndex(c => !TranslateColor(c).HasValue) is int invalidPosition)
+                            View.NotifyInvalidColor(input[invalidPosition]);
+                        else
+                            return (Command.MakeGuess, new Code(input.Select(c => TranslateColor(c)!.Value)));
+
+                        break;
+                }
+            }
+        }
+
+        /// <summary>
+        /// Waits until the user indicates that he or she is ready to continue.
+        /// </summary>
+        public static void WaitUntilReady()
+        {
+            View.PromptReady();
+            var input = Console.ReadLine();
+            if (input is null)
+                Environment.Exit(0);
+        }
+
+        /// <summary>
+        /// Gets the number of blacks and whites for the given code from the
+        /// user.
+        /// </summary>
+        public static (int blacks, int whites) GetBlacksWhites(Code code)
+        {
+            while (true)
+            {
+                View.PromptBlacksWhites(code);
+
+                var input = Console.ReadLine();
+                if (input is null)
+                    Environment.Exit(0);
+
+                var parts = input.Split(',');
+
+                if (parts.Length != 2)
+                    View.PromptTwoValues();
+                else
+                if (!Int32.TryParse(parts[0], out var blacks) || !Int32.TryParse(parts[1], out var whites))
+                    View.PromptValidInteger();
+                else
+                    return (blacks, whites);
+            }
+        }
+
+        /// <summary>
+        /// Gets an integer value from the user.
+        /// </summary>
+        private static int GetInteger(Action prompt)
+        {
+            while (true)
+            {
+                prompt();
+
+                var input = Console.ReadLine();
+                if (input is null)
+                    Environment.Exit(0);
+
+                if (Int32.TryParse(input, out var result))
+                    return result;
+                else
+                    View.PromptValidInteger();
+            }
+        }
+
+        /// <summary>
+        /// Translates the given character into the corresponding color.
+        /// </summary>
+        private static int? TranslateColor(char c) =>
+            ColorsByKey.TryGetValue(c, out var index) ? index : null;
+    }
+}