Pawn captures

main.c

@@ -23,10 +23,24 @@ typedef struct {
   bool whiteToMove;
 } game;
 
+typedef struct {
+  int From;
+  int To;
+} move;
+
 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);
+int pawnMove(game *g, move *moves);
+
+long long fullSet(sets *s) {
+  return s->bishops ^ s->king ^ s->knights ^ s->pawns ^ s->queen ^ s->rooks;
+}
+
+long long fullSetBoth(game *g) {
+  return fullSet(&g->white) ^ fullSet(&g->black);
+}
 
 void print_bitboard(long long bitboard) {
   for (int i = 63; i >= 0; i--) {
@@ -77,18 +91,30 @@ int main() {
       }
       playMoves(g, lineRest);
       printf("info pawns\n");
-      print_bitboard(g->white.pawns | g->black.pawns);
+      // print_bitboard(fullSetBoth(g));
 
     } else if (!strcmp("ucinewgame", token)) {
     } else if (!strcmp("isready", token)) {
       printf("readyok\n");
     } else if (!strcmp("go", token)) {
-      if (g->whiteToMove) {
+
-        printf("bestmove %c2%c4\n", ltz[cnt], ltz[cnt]);
+      move mov[64];
+      int cnt = pawnMove(g, mov);
+      move *m = &mov[0];
+
+      char *end = "";
+      int yTo, xTo, yFrom, xFrom;
+      xTo = m->To % 8;
+      yTo = m->To / 8 + 1;
+      xFrom = m->From % 8;
+      yFrom = m->From / 8 + 1;
+
+      if ((g->whiteToMove && yTo == 8) || (!g->whiteToMove && yTo == 1)) {
+        end = "q\n";
       } else {
-        printf("bestmove %c7%c5\n", ltz[cnt], ltz[cnt]);
+        end = "\n";
       }
-      cnt++;
+      printf("bestmove %c%d%c%d%s", ltz[xFrom], yFrom, ltz[xTo], yTo, end);
     }
   }
 }
@@ -179,7 +205,8 @@ void playMoves(game *g, char *moves) {
       *tmp &= (~bit);
     if (strlen(move) == 5) {
       char c = move[4];
-      c = toupper(c);
+      if (g->whiteToMove)
+        c = toupper(c);
       set = charToSet(g, c);
     }
     *set |= bit;
@@ -218,3 +245,40 @@ long long *findSet(game *g, long long bit) {
     return NULL;
   }
 }
+
+int pawnMove(game *g, move *moves) {
+  long long pawns = g->whiteToMove ? g->white.pawns : g->black.pawns;
+  long long enemy = g->whiteToMove ? fullSet(&g->black) : fullSet(&g->white);
+  long long occupied = fullSetBoth(g);
+
+  int movdir = g->whiteToMove ? 8 : -8;
+  int capLeft = g->whiteToMove ? 7 : -9;
+  int capRight = g->whiteToMove ? 9 : -7;
+
+  size_t index = 0;
+
+  for (int i = 0; i < 64; ++i) {
+    long long bit = 1LL << i;
+    if (!(pawns & bit))
+      continue;
+
+    // forword
+    int to = i + movdir;
+    if (to >= 0 && to < 64 && !(occupied & (1LL << to))) {
+      moves[index++] = (move){.From = i, .To = to};
+    }
+
+    // left
+    to = i + capLeft;
+    if (i % 8 > 0 && (to >= 0 && to < 64) && (enemy & (1LL << to))) {
+      moves[index++] = (move){.From = i, .To = to};
+    }
+
+    // right
+    to = i + capRight;
+    if (i % 8 < 7 && (to >= 0 && to < 64) && (enemy & (1LL << to))) {
+      moves[index++] = (move){.From = i, .To = to};
+    }
+  }
+  return index;
+}