import uuid

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


class User(AbstractUser):
    color = models.CharField(
        max_length=7,
        default='#0000ff',
    )


class Invitation(models.Model):
    token = models.UUIDField(
        default=uuid.uuid4,
        unique=True,
        editable=False,
    )

    created_by = models.ForeignKey(
        User,
        on_delete=models.CASCADE,
        related_name='created_invitations',
    )

    created_at = models.DateTimeField(auto_now_add=True)

    expires_at = models.DateTimeField()

    used_at = models.DateTimeField(
        null=True,
        blank=True,
    )

    @property
    def is_valid(self):
        from django.utils import timezone

        return (
            self.used_at is None
            and self.expires_at > timezone.now()
        )