Hi, I’m Erik Moravec. I design and build exciting software that solves real problems. Or is just fun.

1def best_bot_move(board: Any, *, bot_color: bool | None = None, depth: int = 1) -> Any:
2  legal_moves = list(board.legal_moves)
3  if not legal_moves:
4    raise ValueError("No legal bot moves available")
5
6  if bot_color is None:
7    bot_color = board.turn
8
9  if depth <= 1:
10    return best_capture_or_random_move(board)
11
12  ordered_moves = order_moves(board, legal_moves)
13  # depth-based minimax path for higher bot levels
14  ...

1def order_moves(board: Any, legal_moves: list[Any]) -> list[Any]:
2    ordered: list[tuple[int, Any]] = []
3    for move in legal_moves:
4        priority = 0
5        if board.is_capture(move):
6            priority += 100
7            if board.is_en_passant(move):
8                priority += PIECE_VALUES[1]
9            else:
10                target_piece = board.piece_at(move.to_square)
11                if target_piece is not None:
12                    priority += PIECE_VALUES.get(target_piece.piece_type, 0)
13
14        board.push(move)
15        if board.is_checkmate():
16            priority += 10_000
17        elif board.is_check():
18            priority += 50
19        board.pop()
20
21        ordered.append((priority, move))
22
23    ordered.sort(key=lambda row: row[0], reverse=True)
24    return [row[1] for row in ordered]
25
26
27def best_capture_or_random_move(board: Any) -> Any:
28    legal_moves = list(board.legal_moves)
29    if not legal_moves:
30        raise ValueError("No legal bot moves available")
31
32    best_capture_score = -1
33    best_captures: list[Any] = []
34    for move in legal_moves:
35        capture_score = 0
36        if board.is_capture(move):
37            if board.is_en_passant(move):
38                capture_score = PIECE_VALUES[1]
39            else:
40                target_piece = board.piece_at(move.to_square)
41                if target_piece is not None:
42                    capture_score = PIECE_VALUES.get(target_piece.piece_type, 0)
43
44        if capture_score > best_capture_score:
45            best_capture_score = capture_score
46            best_captures = [move]
47        elif capture_score == best_capture_score:
48            best_captures.append(move)
49
50    return random.choice(best_captures) if best_captures else random.choice(legal_moves)