From 64b979b9abcaffec2bfd6722df1d244186578330 Mon Sep 17 00:00:00 2001
From: k <markers711@gmail.com>
Date: Thu, 12 Jun 2025 04:49:44 -0400
Subject: [PATCH] Bit board updates based on moves

---
 main.c | 152 ++++++++++++++++++++++++++++++++++++++-------------------
 1 file changed, 101 insertions(+), 51 deletions(-)

diff --git a/main.c b/main.c
index 5b9faf3..947cff5 100644
--- a/main.c
+++ b/main.c
@@ -24,6 +24,9 @@ typedef struct {
 } game;
 
 game *fenGame(char *str);
+void playMoves(game *g, char *moves);
+long long *findSet(game *g, long long bit);
+long long *charToSet(game *g, char c);
 
 void print_bitboard(long long bitboard) {
   for (int i = 63; i >= 0; i--) {
@@ -64,7 +67,6 @@ int main() {
       return 0;
     } else if (!strcmp("setoption", token)) {
     } else if (!strcmp("position", token)) {
-      game *g;
       token = strtok_r(lineRest, " ", &lineRest);
       if (!strcmp("fen", token)) {
         g = fenGame(lineRest + 1);
@@ -73,23 +75,55 @@ int main() {
       } else {
         g = fenGame("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1");
       }
-      token = strtok_r(lineRest, " ", &lineRest);
-      if (!strcmp("moves", token)) {
-        // TODO
-      }
-      print_bitboard(g->white.pawns);
-      print_bitboard(g->black.pawns);
+      playMoves(g, lineRest);
+      printf("info pawns\n");
+      print_bitboard(g->white.pawns | g->black.pawns);
 
     } else if (!strcmp("ucinewgame", token)) {
     } else if (!strcmp("isready", token)) {
       printf("readyok\n");
     } else if (!strcmp("go", token)) {
-      printf("bestmove %c2%c4\n", ltz[cnt], ltz[cnt]);
+      if (g->whiteToMove) {
+        printf("bestmove %c2%c4\n", ltz[cnt], ltz[cnt]);
+      } else {
+        printf("bestmove %c7%c5\n", ltz[cnt], ltz[cnt]);
+      }
       cnt++;
     }
   }
 }
 
+long long *charToSet(game *g, char c) {
+  switch (c) {
+  case 'P':
+    return &g->white.pawns;
+  case 'N':
+    return &g->white.knights;
+  case 'B':
+    return &g->white.bishops;
+  case 'R':
+    return &g->white.rooks;
+  case 'Q':
+    return &g->white.queen;
+  case 'K':
+    return &g->white.king;
+  case 'p':
+    return &g->black.pawns;
+  case 'n':
+    return &g->black.knights;
+  case 'b':
+    return &g->black.bishops;
+  case 'r':
+    return &g->black.rooks;
+  case 'q':
+    return &g->black.queen;
+  case 'k':
+    return &g->black.king;
+  default:
+    return NULL;
+  }
+}
+
 game *fenGame(char *str) {
   int rank = 7;
   int file = 0;
@@ -116,49 +150,9 @@ game *fenGame(char *str) {
     }
 
     long long bit = 1LL << (rank * 8 + file);
-    switch (*str) {
-    case 'P':
-      g->white.pawns |= bit;
-      break;
-    case 'N':
-      g->white.knights |= bit;
-      break;
-    case 'B':
-      g->white.bishops |= bit;
-      break;
-    case 'R':
-      g->white.rooks |= bit;
-      break;
-    case 'Q':
-      g->white.queen |= bit;
-      break;
-    case 'K':
-      g->white.king |= bit;
-      break;
-    case 'p':
-      g->black.pawns |= bit;
-      break;
-    case 'n':
-      g->black.knights |= bit;
-      break;
-    case 'b':
-      g->black.bishops |= bit;
-      break;
-    case 'r':
-      g->black.rooks |= bit;
-      break;
-    case 'q':
-      g->black.queen |= bit;
-      break;
-    case 'k':
-      g->black.king |= bit;
-      break;
-    default:
-      fprintf(stderr,
-              "Error: Unknown piece character in FEN: %c at position %zu\n",
-              *str, pos);
-      break;
-    }
+    long long *set = charToSet(g, *str);
+    if (set)
+      *set |= bit;
     file++;
     str++;
   }
@@ -166,3 +160,59 @@ game *fenGame(char *str) {
   g->whiteToMove = (*str == 'w') ? true : false;
   return g;
 }
+
+void playMoves(game *g, char *moves) {
+  char *move;
+  move = strtok_r(moves, " ", &moves);
+  move = strtok_r(moves, " ", &moves);
+  while (move) {
+    long long bit = 1LL << ((move[1] - '0' - 1) * 8 + (move[0] - 'a'));
+    long long *set = findSet(g, bit);
+    if (!set) {
+      printf("info fuck\n");
+      return;
+    }
+    *set &= (~bit);
+    bit = 1LL << ((move[3] - '0' - 1) * 8 + (move[2] - 'a'));
+    long long *tmp = findSet(g, bit);
+    if (tmp)
+      *tmp &= (~bit);
+    if (strlen(move) == 5) {
+      set = charToSet(g, move[4]);
+    }
+    *set |= bit;
+
+    move = strtok_r(moves, " ", &moves);
+    g->whiteToMove = !g->whiteToMove;
+  }
+}
+
+long long *findSet(game *g, long long bit) {
+  if (g->white.pawns & bit) {
+    return &g->white.pawns;
+  } else if (g->white.knights & bit) {
+    return &g->white.knights;
+  } else if (g->white.bishops & bit) {
+    return &g->white.bishops;
+  } else if (g->white.rooks & bit) {
+    return &g->white.rooks;
+  } else if (g->white.queen & bit) {
+    return &g->white.queen;
+  } else if (g->white.king & bit) {
+    return &g->white.king;
+  } else if (g->black.pawns & bit) {
+    return &g->black.pawns;
+  } else if (g->black.knights & bit) {
+    return &g->black.knights;
+  } else if (g->black.bishops & bit) {
+    return &g->black.bishops;
+  } else if (g->black.rooks & bit) {
+    return &g->black.rooks;
+  } else if (g->black.queen & bit) {
+    return &g->black.queen;
+  } else if (g->black.king & bit) {
+    return &g->black.king;
+  } else {
+    return NULL;
+  }
+}