from __future__ import annotations

from enum import Enum, auto

from .db import User


class Permission(Enum):
    tag = auto()
    untag = auto()
    edit = auto()
    delete = auto()

    def __repr__(self) -> str:
        return self.name

    @classmethod
    def _(
        cls,
        actor: User | None,
        target: User,
    ) -> set[Permission]:
        result = set()

        if actor is None:
            return result

        if isinstance(target, User):
            if actor.is_admin():
                if target != actor:
                    result |= set([cls.tag, cls.untag, cls.delete])

                result.add(cls.edit)

        return result