blunderboard/src/blunderboard/movegenerator.py

from blunderboard.blunderevaluator import BlunderEvaluator


def coords_to_field(row: int, column: int):
    columns = "abcdefgh"
    return "%c%d" % (columns[column], row + 1)


class MoveGenerator:
    def __init__(self, blunder_evaluator: BlunderEvaluator):
        self.state: State = InitState(blunder_evaluator)

    def reset(self) -> None:
        print("reset")
        self.state = self.state.reset()

    def put(self, row: int, column: int) -> None:
        print("put %s" % coords_to_field(row, column))
        self.state = self.state.put(row, column)

    def take(self, row: int, column: int) -> None:
        print("take %s" % coords_to_field(row, column))
        self.state = self.state.take(row, column)


class State:
    def __init__(self, blunder_evaluator: BlunderEvaluator):
        self.blunder_evaluator = blunder_evaluator

    def reset(self) -> "State":
        self.blunder_evaluator.reset()
        return InitState(self.blunder_evaluator)

    def put(self, row: int, column: int) -> "State":
        print("ignored invalid put")
        return self

    def take(self, row: int, column: int) -> "State":
        print("ignored invalid take")
        return self


class InitState(State):
    def reset(self) -> State:
        super().reset()
        return self

    def take(self, row: int, column: int) -> State:
        return TakeState(self.blunder_evaluator, coords_to_field(row, column))


class TakeState(State):
    def __init__(self, blunder_evaluator: BlunderEvaluator, from_field: str):
        super().__init__(blunder_evaluator)
        self.from_field = from_field

    def put(self, row: int, column: int) -> State:
        to_field = coords_to_field(row, column)
        if self.from_field == to_field:
            print("ignored self-move")
            return InitState(self.blunder_evaluator)
        move = self.from_field + to_field
        print("move %s" % move)
        self.blunder_evaluator.move(move)
        return InitState(self.blunder_evaluator)

    def take(self, row: int, column: int) -> State:
        return TakeTakeState(
            self.blunder_evaluator, self.from_field, coords_to_field(row, column)
        )


class TakeTakeState(State):
    def __init__(
        self, blunder_evaluator: BlunderEvaluator, from_field: str, from2_field: str
    ):
        super().__init__(blunder_evaluator)
        self.from_field = from_field
        self.from2_field = from2_field

    def put(self, row: int, column: int) -> State:
        to_field = coords_to_field(row, column)
        if self.from2_field == to_field:
            move = self.from_field + to_field
        elif self.from_field == to_field:
            move = self.from2_field + to_field
        elif (
            self.from_field[1] == self.from2_field[1]
            and self.from_field[1] == to_field[1]
        ):
            # king-side castling
            if (
                self.from_field in ["e1", "e8"]
                and self.from2_field in ["h1", "h8"]
                and to_field in ["f1", "f8", "g1", "g8"]
            ):
                return KingCastleState(
                    self.blunder_evaluator, self.from_field, self.from2_field, to_field
                )
            # queen-side castling
            if (
                self.from_field in ["e1", "e8"]
                and self.from2_field in ["a1", "a8"]
                and to_field in ["c1", "c8", "d1", "d8"]
            ):
                return QueenCastleState(
                    self.blunder_evaluator, self.from_field, self.from2_field, to_field
                )
            print("ignored invalid put")
            return self
        else:
            print("ignored invalid put")
            return self
        print("move %s" % move)
        self.blunder_evaluator.move(move)
        return InitState(self.blunder_evaluator)


class KingCastleState(State):
    def __init__(
        self,
        blunder_evaluator: BlunderEvaluator,
        from_field: str,
        from2_field: str,
        to_field: str,
    ):
        super().__init__(blunder_evaluator)
        self.from_field = from_field
        self.from2_field = from2_field
        self.to_field = to_field

    def put(self, row: int, column: int) -> State:
        to2_field = coords_to_field(row, column)
        if self.to_field[1] == to2_field[1]:
            if to2_field in ["f1", "g1"]:
                move = "e1g1"
            elif to2_field in ["f8", "g8"]:
                move = "e8g8"
            else:
                print("ignored invalid put")
                return self
        else:
            print("ignored invalid put")
            return self
        print("move %s" % move)
        self.blunder_evaluator.move(move)
        return InitState(self.blunder_evaluator)


class QueenCastleState(State):
    def __init__(
        self,
        blunder_evaluator: BlunderEvaluator,
        from_field: str,
        from2_field: str,
        to_field: str,
    ):
        super().__init__(blunder_evaluator)
        self.from_field = from_field
        self.from2_field = from2_field
        self.to_field = to_field

    def put(self, row: int, column: int) -> State:
        to2_field = coords_to_field(row, column)
        if self.to_field[1] == to2_field[1]:
            if to2_field in ["c1", "d1"]:
                move = "e1c1"
            elif to2_field in ["c8", "d8"]:
                move = "e8c8"
            else:
                print("ignored invalid put")
                return self
        else:
            print("ignored invalid put")
            return self
        print("move %s" % move)
        self.blunder_evaluator.move(move)
        return InitState(self.blunder_evaluator)