"""This module contains common utilities for handling models."""

import enum
from typing import Callable

import sqlalchemy


class SortOrder(enum.Enum):
    """Possible sort orders for database queries."""

    asc = 'asc'
    ASC = 'asc'
    desc = 'desc'
    DESC = 'desc'

    @property
    def call(self) -> Callable:
        """Returns the sqlalchemy sort function depending on the instance value."""

        if self.value == 'asc':
            return sqlalchemy.asc
        elif self.value == 'desc':
            return sqlalchemy.desc
        else:
            raise RuntimeError("Logic error.")