from __future__ import annotations

import typing as t


class Trapezoid:
    @property
    def lower_left_node_index(self) -> t.Optional[int]:
        return self._lower_left_node_index

    @property
    def lower_right_node_index(self) -> t.Optional[int]:
        return self._lower_right_node_index

    @property
    def upper_left_node_index(self) -> t.Optional[int]:
        return self._upper_left_node_index

    @property
    def upper_right_node_index(self) -> t.Optional[int]:
        return self._upper_right_node_index

    def reset_lower_left(self) -> None:
        self._lower_left_node_index = None

    def reset_lower_right(self) -> None:
        self._lower_right_node_index = None

    def reset_upper_left(self) -> None:
        self._upper_left_node_index = None

    def reset_upper_right(self) -> None:
        self._upper_right_node_index = None

    def set_as_lower_left(self, value: Trapezoid) -> None:
        self._lower_left_node_index = value.leaf_index
        value._lower_right_node_index = self.leaf_index

    def set_as_lower_right(self, value: Trapezoid) -> None:
        self._lower_right_node_index = value.leaf_index
        value._lower_left_node_index = self.leaf_index

    def set_as_upper_left(self, value: Trapezoid) -> None:
        self._upper_left_node_index = value.leaf_index
        value._upper_right_node_index = self.leaf_index

    def set_as_upper_right(self, value: Trapezoid) -> None:
        self._upper_right_node_index = value.leaf_index
        value._upper_left_node_index = self.leaf_index

    _lower_left_node_index: t.Optional[int]
    _lower_right_node_index: t.Optional[int]
    _upper_left_node_index: t.Optional[int]
    _upper_right_node_index: t.Optional[int]

    __slots__ = (
        'above_edge_index', 'below_edge_index', 'is_component', 'leaf_index',
        'left_point_index', 'right_point_index', '_lower_left_node_index',
        '_lower_right_node_index', '_upper_left_node_index',
        '_upper_right_node_index'
    )

    def __init__(self,
                 is_component: bool,
                 left_point_index: int,
                 right_point_index: int,
                 below_edge_index: int,
                 above_edge_index: int,
                 leaf_index: int) -> None:
        (
            self.above_edge_index, self.below_edge_index, self.is_component,
            self.left_point_index, self.leaf_index, self.right_point_index
        ) = (
            above_edge_index, below_edge_index, is_component, left_point_index,
            leaf_index, right_point_index
        )
        self._lower_left_node_index = self._lower_right_node_index = None
        self._upper_left_node_index = self._upper_right_node_index = None