Introduce HandRank

71_Poker/csharp/Cards/Hand.cs

@@ -1,5 +1,5 @@
 using System.Text;
-
+using static Poker.Cards.HandRank;
 namespace Poker.Cards;
 
 internal class Hand
@@ -7,15 +7,11 @@ internal class Hand
     public static readonly Hand Empty = new Hand();
 
     private readonly Card[] _cards;
-    private readonly string _name1;
-    private readonly string _name2;
 
     private Hand()
     {
         _cards = Array.Empty<Card>();
-        _name1 = "";
-        _name2 = "";
-        Name = "";
+        Rank = None;
     }
 
     public Hand(IEnumerable<Card> cards)
@@ -26,16 +22,15 @@ internal class Hand
     private Hand(IEnumerable<Card> cards, bool isAfterDraw)
     {
         _cards = cards.ToArray();
-        (Rank, _name1, _name2, HighCard, KeepMask) = Analyze();
-        Name = GetHandName();
+        (Rank, HighCard, KeepMask) = Analyze();
 
-        IsWeak = Rank < 10
-            || Rank == 10 && isAfterDraw
-            || Rank <= 12 && HighCard.Rank <= 6;
+        IsWeak = Rank < PartialStraight
+            || Rank == PartialStraight && isAfterDraw
+            || Rank <= TwoPair && HighCard.Rank <= 6;
     }
 
-    public string Name { get; }
-    public int Rank { get; }
+    public string Name => Rank.ToString(HighCard);
+    public HandRank Rank { get; }
     public Card HighCard { get; }
     public int KeepMask { get; set; }
     public bool IsWeak { get; }
@@ -48,7 +43,7 @@ internal class Hand
         return new Hand(_cards, isAfterDraw: true);
     }
 
-    private (int, string, string, Card, int) Analyze()
+    private (HandRank, Card, int) Analyze()
     {
         var suitMatchCount = 0;
         for (var i = 0; i < _cards.Length; i++)
@@ -60,31 +55,31 @@ internal class Hand
         }
         if (suitMatchCount == 4)
         {
-            return (15, "A Flus", "h in", _cards[0], 0b11111);
+            return (Flush, _cards[0], 0b11111);
         }
         var sortedCards = _cards.OrderBy(c => c.Rank).ToArray();
 
-        var handRank = 0;
+        var handRank = Schmaltz;
         var keepMask = 0;
         Card highCard = default;
-        var handName1 = "";
-        var handName2 = "";
         for (var i = 0; i < sortedCards.Length - 1; i++)
         {
-            if (sortedCards[i].Rank == sortedCards[i+1].Rank)
+            var matchesNextCard = sortedCards[i].Rank == sortedCards[i+1].Rank;
+            var matchesPreviousCard = i > 0 && sortedCards[i].Rank == sortedCards[i - 1].Rank;
+
+            if (matchesNextCard)
             {
                 keepMask |= 0b11 << i;
                 highCard = sortedCards[i];
-                (handRank, handName1, handName2) =
-                    (handRank, i > 0 && sortedCards[i].Rank == sortedCards[i - 1].Rank) switch
-                    {
-                        (<11, _) => (11, "A Pair", " of "),
-                        (11, true) => (13, "Three", " "),
-                        (11, _) => (12, "Two P", "air, "),
-                        (12, _) => (16, "Full H", "ouse, "),
-                        (_, true) => (17, "Four", " "),
-                        _ => (16, "Full H", "ouse, ")
-                    };
+                handRank = matchesPreviousCard switch
+                {
+                    _ when handRank < Pair => Pair,
+                    true when handRank == Pair => Three,
+                    _ when handRank == Pair => TwoPair,
+                    _ when handRank == TwoPair => FullHouse,
+                    true => Four,
+                    _ => FullHouse
+                };
             }
         }
         if (keepMask == 0)
@@ -92,36 +87,21 @@ internal class Hand
             if (sortedCards[3] - sortedCards[0] == 3)
             {
                 keepMask=0b1111;
-                handRank=10;
+                handRank=PartialStraight;
             }
             if (sortedCards[4] - sortedCards[1] == 3)
             {
-                if (handRank == 10)
+                if (handRank == PartialStraight)
                 {
-                    return (14, "Straig", "ht", sortedCards[4], 0b11111);
+                    return (Straight, sortedCards[4], 0b11111);
                 }
-                handRank=10;
+                handRank=PartialStraight;
                 keepMask=0b11110;
             }
         }
-        return handRank < 10
-            ? (9, "Schmal", "tz, ", sortedCards[4], 0b11000)
-            : (handRank, handName1, handName2, highCard, keepMask);
-    }
-
-    private string GetHandName()
-    {
-        var sb = new StringBuilder(_name1).Append(_name2);
-        if (_name1 == "A Flus")
-        {
-            sb.Append(HighCard.Suit).AppendLine();
-        }
-        else
-        {
-            sb.Append(HighCard.Rank)
-                .AppendLine(_name1 == "Schmal" || _name1 == "Straig" ? " High" : "'s");
-        }
-        return sb.ToString();
+        return handRank < PartialStraight
+            ? (Schmaltz, sortedCards[4], 0b11000)
+            : (handRank, highCard, keepMask);
     }
 
     public override string ToString()

71_Poker/csharp/Cards/HandRank.cs

@@ -0,0 +1,34 @@
+namespace Poker.Cards;
+
+internal class HandRank
+{
+    public static HandRank None = new(0, "");
+    public static HandRank Schmaltz = new(1, "schmaltz, ", c => $"{c.Rank} high");
+    public static HandRank PartialStraight = new(2, ""); // The original code does not assign a display string here
+    public static HandRank Pair = new(3, "a pair of ", c => $"{c.Rank}'s");
+    public static HandRank TwoPair = new(4, "two pair, ", c => $"{c.Rank}'s");
+    public static HandRank Three = new(5, "three ", c => $"{c.Rank}'s");
+    public static HandRank Straight = new(6, "straight", c => $"{c.Rank} high");
+    public static HandRank Flush = new(7, "a flush in ", c => c.Suit.ToString());
+    public static HandRank FullHouse = new(8, "full house, ", c => $"{c.Rank}'s");
+    public static HandRank Four = new(9, "four ", c => $"{c.Rank}'s");
+    // The original code does not detect a straight flush or royal flush
+
+    private readonly int _value;
+    private readonly string _displayName;
+    private readonly Func<Card, string> _suffixSelector;
+
+    private HandRank(int value, string displayName, Func<Card, string>? suffixSelector = null)
+    {
+        _value = value;
+        _displayName = displayName;
+        _suffixSelector = suffixSelector ?? (_ => "");
+    }
+
+    public string ToString(Card highCard) => $"{_displayName}{_suffixSelector.Invoke(highCard)}";
+
+    public static bool operator >(HandRank x, HandRank y) => x._value > y._value;
+    public static bool operator <(HandRank x, HandRank y) => x._value < y._value;
+    public static bool operator >=(HandRank x, HandRank y) => x._value >= y._value;
+    public static bool operator <=(HandRank x, HandRank y) => x._value <= y._value;
+}

71_Poker/csharp/Game.cs

@@ -59,12 +59,12 @@ internal class Game
             Z = table.Computer.Hand.Rank switch
             {
                 _ when table.Computer.Hand.IsWeak =>
-                    table.Computer.BluffIf(Get0To9() > 7, 0b11100) ??
-                    table.Computer.BluffIf(Get0To9() > 7, 0b11110) ??
+                    table.Computer.BluffIf(Get0To9() < 2, 0b11100) ??
+                    table.Computer.BluffIf(Get0To9() < 2, 0b11110) ??
                     table.Computer.BluffIf(Get0To9() < 1, 0b11111) ??
                     1,
-                < 13 => table.Computer.BluffIf(Get0To9() < 2) ?? 0,
-                <= 16 => 35,
+                _ when table.Computer.Hand.Rank < HandRank.Three => table.Computer.BluffIf(Get0To9() < 2) ?? 0,
+                _ when table.Computer.Hand.Rank < HandRank.FullHouse => 35,
                 _ when Get0To9() < 1 => 35,
                 _ => 2
             };
@@ -90,8 +90,8 @@ internal class Game
             {
                 _ when table.Computer.IsBluffing => 28,
                 _ when table.Computer.Hand.IsWeak => 1,
-                < 13 => Get0To9() == 0 ? 19 : 2,
-                < 16 => Get0To9() == 8 ? 11 : 19,
+                _ when table.Computer.Hand.Rank < HandRank.Three => Get0To9() == 0 ? 19 : 2,
+                _ when table.Computer.Hand.Rank < HandRank.FullHouse => Get0To9() == 0 ? 11 : 19,
                 _ => 2
             };