# -*- coding: utf-8 -*-

from typing import Optional, Any

from .Column import Column
from .ColumnSet import ColumnSet

class SingleForeignKey:

    def __init__(self, child_col: Column, parent_col: Column):
        self.__child_col = child_col
        self.__parent_col = parent_col
        self.__iterable = (self.__child_col, self.__parent_col)

    def __len__(self):
        return 2

    def __iter__(self):
        yield from self.__iterable

    def __repr__(self):
        return f'{self.__child_col.table.name}.{self.__child_col.name} -> {self.__parent_col.table.name}.{self.__parent_col.name}'

    def __getitem__(self, index):
        return self.__iterable[index]

    @property
    def child_column(self):
        return self.__child_col

    @property
    def parent_column(self):
        return self.__parent_col