from functools import cached_property

from django.contrib.auth.models import User
from django.db import models

from lib.core.db.models.mixins import DateAware


class SharedPermissionBase(DateAware, models.Model):
    class Meta:
        abstract = True

    user = models.ForeignKey(User, on_delete=models.CASCADE)
    view = models.BooleanField(default=True)
    change = models.BooleanField(default=False)
    delete = models.BooleanField(default=False)
    add = models.BooleanField(default=False)

    # item = models.IntegerField(default=NotImplementedError('Must be defined in inheriting class'))
    @cached_property
    def perms(self):
        perms = filter(None, [
            'read' if self.view else False,
            'change' if self.change else False,
            'delete' if self.delete else False,
            'add' if self.add else False,
        ])
        return list(perms)

    def __str__(self):
        return f'{self.user.username} ({", ".join(self.perms)})'