feat: adequately generate pseudolegal moves

1 files changed, 79 insertions, 3 deletions

diff --git a/src/main.c b/src/main.c
index c84fb6a..13013f8 100644
--- a/src/main.c
+++ b/src/main.c
@@ -468,9 +468,85 @@ int generate_pseudolegal_moves(Move* moves, int* board, int color) {
 
   for (int rank = 7; rank >= 0; rank--) {
     for (int file = 0; file < 8; file++) {
-      int destination = rank * 16 + file;
-      Move* next_ptr = moves ? moves + moves_count : NULL;
-      moves_count += generate_moves_with_destination(next_ptr, board, color, destination);
+      int origin = rank * 16 + file;
+      int piece = board[origin];
+      int* ray_move = NULL;
+      if (piece % 2 == color) {
+        switch (piece & NO_COLOR) {
+          case KNIGHT:
+            ray_move = knightMoves;
+            break;
+          case BISHOP:
+            ray_move = bishopMoves;
+            break;
+          case ROOK:
+            ray_move = rookMoves;
+            break;
+          case QUEEN:
+            ray_move = queenMoves;
+            break;
+          case KING:
+            ray_move = kingMoves;
+            break;
+          default:
+            break;
+        }
+
+        while(ray_move && *ray_move) {
+          for (int destination = origin + *ray_move; !(destination & 0x88); destination += *ray_move) {
+            if (board[destination] == EMPTY || board[destination] % 2 != color) {
+              if (moves) moves[moves_count] = (Move){ origin, destination, 0 };
+              moves_count++;
+            }
+            // Knights and kings do not actually have "ray" moves
+            if ((piece & NO_COLOR) == KNIGHT || (piece & NO_COLOR) == KING) break;
+
+            // Stop ray move after we hit anything
+            if (board[destination] != EMPTY) break;
+          }
+          ray_move++;
+        }
+
+        // Handle pawns separately
+        if (piece == (PAWN | WHITE)) {
+          if (rank < 7 && board[origin + 16] == EMPTY) {
+            if (moves) moves[moves_count] = (Move){ origin, origin + 16, 0 };
+            moves_count++;
+            if (rank == 1 && board[origin + 32] == EMPTY) { // Pawns on rank 1 can move 2 squares up
+              if (moves) moves[moves_count] = (Move){ origin, origin + 32, 0 };
+              moves_count++;
+            }
+          }
+          // Attacks
+          if ((board[origin + 15] != EMPTY) && board[origin + 15] % 2 == BLACK) {
+              if (moves) moves[moves_count] = (Move){ origin, origin + 15, 0 };
+              moves_count++;
+          }
+          if ((board[origin + 17] != EMPTY) && board[origin + 17] % 2 == BLACK) {
+              if (moves) moves[moves_count] = (Move){ origin, origin + 17, 0 };
+              moves_count++;
+          }
+        }
+        if (piece == (PAWN | BLACK)) {
+          if (rank > 0 && board[origin - 16] == EMPTY) {
+            if (moves) moves[moves_count] = (Move){ origin, origin - 16, 0 };
+            moves_count++;
+            if (rank == 6 && board[origin - 32] == EMPTY) { // Pawns on rank 6 can move 2 squares down
+              if (moves) moves[moves_count] = (Move){ origin, origin - 32, 0 };
+              moves_count++;
+            }
+          }
+          // Attacks
+          if ((board[origin - 15] != EMPTY) && board[origin - 15] % 2 == WHITE) {
+              if (moves) moves[moves_count] = (Move){ origin, origin - 15, 0 };
+              moves_count++;
+          }
+          if ((board[origin - 17] != EMPTY) && board[origin - 17] % 2 == WHITE) {
+              if (moves) moves[moves_count] = (Move){ origin, origin - 17, 0 };
+              moves_count++;
+          }
+        }
+      }
     }
   }