From 04439b542b212f9eb169ad10c3d2461765ed8208 Mon Sep 17 00:00:00 2001
From: Coding with Tom <146443103+hcsalmon1@users.noreply.github.com>
Date: Mon, 20 Jan 2025 16:57:11 +0000
Subject: [PATCH] Create Perft_Func

---
 C#/Cleaner and slower version/Perft_Func | 81 ++++++++++++++++++++++++
 1 file changed, 81 insertions(+)
 create mode 100644 C#/Cleaner and slower version/Perft_Func

diff --git a/C#/Cleaner and slower version/Perft_Func b/C#/Cleaner and slower version/Perft_Func
new file mode 100644
index 0000000..bd53353
--- /dev/null
+++ b/C#/Cleaner and slower version/Perft_Func	
@@ -0,0 +1,81 @@
+using System;
+using System.Collections.Generic;
+
+namespace CEngineCopy
+{
+    internal class Perft_Func
+    {
+
+        static int PerftFunctions(int depth, int ply)
+        {
+            //Same as move list, span to avoid heap allocation
+            Span<int> startingSquares = stackalloc int[50];
+            Span<int> targetSquares = stackalloc int[50];
+            Span<int> tags = stackalloc int[50];
+            Span<int> pieces = stackalloc int[50];
+
+            int moveCount = GenMoves.GetMoves(ref startingSquares, ref targetSquares, ref tags, ref pieces);
+
+            if (depth == 1)
+            {
+                return moveCount;
+            }
+
+            int nodes = 0, priorNodes;
+            int copyEp = Board.ep_global;
+            Span<bool> copy_castle = stackalloc bool[4];
+            copy_castle[0] = Board.castle_rights_global[0];
+            copy_castle[1] = Board.castle_rights_global[1];
+            copy_castle[2] = Board.castle_rights_global[2];
+            copy_castle[3] = Board.castle_rights_global[3];
+
+            for (int move_index = 0; move_index < moveCount; ++move_index)
+            {
+                int startingSquareCopy = startingSquares[move_index];
+                int targetSquareCopy = targetSquares[move_index];
+                int piece = pieces[move_index];
+                int tag = tags[move_index];
+
+                int captureIndex = Make_Move.MakeMove(startingSquareCopy, targetSquareCopy, tag, piece);
+
+                priorNodes = nodes;
+                nodes += PerftFunctions(depth - 1, ply + 1);
+
+                #region Unmakemove
+
+                Make_Move.UnmakeMove(startingSquareCopy, targetSquareCopy, piece, tag, captureIndex);
+
+                Board.castle_rights_global[0] = copy_castle[0];
+                Board.castle_rights_global[1] = copy_castle[1];
+                Board.castle_rights_global[2] = copy_castle[2];
+                Board.castle_rights_global[3] = copy_castle[3];
+                Board.ep_global = copyEp;
+
+                #endregion
+
+                //if (ply == 0)
+                //{
+                //   PrintMoveNoNL(move_list[move_index]);
+                //   Console.Write(": %llu\n", nodes - priorNodes);
+                //}
+            }
+
+            return nodes;
+        }
+
+        public static void RunPerftFunctions(int depth)
+        {
+            DateTime start = DateTime.Now;
+
+            int nodes = PerftFunctions(depth, 0);
+
+            DateTime end = DateTime.Now;
+            TimeSpan elapsed = end - start;
+            int elapsedTimeInMs = (int)elapsed.TotalMilliseconds; ;
+            Console.WriteLine($"Nodes: {nodes}");
+
+            Console.WriteLine($"Elapsed time: {elapsedTimeInMs}ms");
+        }
+
+    }
+}