adding get legal moves

1 files changed, 60 insertions, 0 deletions

diff --git a/src/moves.cpp b/src/moves.cpp
index f417499..65a380a 100644
--- a/src/moves.cpp
+++ b/src/moves.cpp
@@ -1,3 +1,63 @@
+#include <array>
+#include <cstdint>
+
+#include "board.hpp"
 #include "moves.hpp"
 
+std::vector<Move> GetLegalMoves(board *b) {
+  std::vector<Move> moves;
+  moves.reserve(50); // almost all position dont have that many moves
+
+  constexpr std::array<int, 4> rook_Moves{-1, 1, 8, -8};
+  constexpr std::array<int, 4> bishop_Moves{-9, 9, -7, 7};
+
+  for (int i = 0; i < sizeof(b->pieces) / sizeof(b->pieces[0]); i++) {
+    Piece piece = b->pieces[i];
+    if (piece.type == NONE) {
+      continue;
+    }
+    if (piece.color != b->turn)
+      continue;
+
+    // Add support for other pieces
+    if (piece.type == BISHOP) {
+      GenerateSlidingMoves(b, i, bishop_Moves, moves);
+    }
+    if (piece.type == ROOK) {
+      GenerateSlidingMoves(b, i, rook_Moves, moves);
+    }
+  };
+
+  return moves;
+}
+Position IndexToPosition(int i) {
+  uint8_t rank = i / 8; // 0-7
+  uint8_t file = i % 8; // 0-7
+  return {rank, file};
+}
+void GenerateSlidingMoves(board *b, int from,
+                          const std::array<int, 4> &directions,
+                          std::vector<Move> &moves) {
+  for (int i = 0; i < directions.size(); i++) {
+    int direction = directions[i];
 
+    int i2 = from;
+    while (true) {
+      i2 += direction;
+      if (i2 >= 64 || i2 < 0) {
+        break;
+      }
+      if (b->pieces[i2].color == b->turn && b->pieces[i2].type != NONE) {
+        break;
+      }
+      if ((direction == 1 || direction == -1) &&
+          (i2 / 8 != (i2 - direction) / 8)) {
+        break;
+      }
+      moves.push_back({IndexToPosition(i2), IndexToPosition(i2)});
+      if (b->pieces[i2].color != b->turn && b->pieces[i2].type != NONE) {
+        break;
+      }
+    }
+  };
+};