def defensive_move(puzzle: Puzzle) -> bool:
# like quiet_move, but on last move
# at least 3 legal moves
if puzzle.mainline[-2].board().legal_moves.count() < 3:
return False
node = puzzle.mainline[-1]
# no check given, no piece taken
if node.board().is_check() or util.is_capture(node):
return False
# no piece attacked
if util.attacked_opponent_pieces(node.board(), node.move.to_square,
puzzle.pov):
return False
# no advanced pawn push
return not util.is_advanced_pawn_move(node)
def quiet_move(puzzle: Puzzle) -> bool:
for node in puzzle.mainline:
if (
# on player move, not the last move of the puzzle
node.turn() != puzzle.pov and not node.is_end() and
# no check given or escaped
not node.board().is_check()
and not node.parent.board().is_check() and
# no capture made or threatened
not util.is_capture(node)
and not util.attacked_opponent_pieces(
node.board(), node.move.to_square, puzzle.pov) and
# no advanced pawn push
not util.is_advanced_pawn_move(node)
and util.moved_piece_type(node) != KING):
return True
return False
def advanced_pawn(puzzle: Puzzle) -> bool:
for node in puzzle.mainline:
if util.is_advanced_pawn_move(node):
return True
return False