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

from apps.core.models import TimeStampedModel


class User(AbstractUser):
    """Aurora Moments account. Email is the login identifier; username is the
    public @handle shown on profiles."""

    email = models.EmailField(unique=True)
    display_name = models.CharField(max_length=150, blank=True)
    bio = models.TextField(max_length=500, blank=True)
    avatar = models.ImageField(upload_to="avatars/", blank=True, null=True)
    is_private = models.BooleanField(
        default=False,
        help_text="If true, new followers must be approved before they can see followers-only Moments.",
    )

    USERNAME_FIELD = "email"
    REQUIRED_FIELDS = ["username"]

    def __str__(self):
        return self.username


class Follow(TimeStampedModel):
    class Status(models.TextChoices):
        PENDING = "pending", "Pending"
        ACCEPTED = "accepted", "Accepted"

    follower = models.ForeignKey(User, related_name="following_edges", on_delete=models.CASCADE)
    following = models.ForeignKey(User, related_name="follower_edges", on_delete=models.CASCADE)
    status = models.CharField(max_length=10, choices=Status.choices, default=Status.ACCEPTED)

    class Meta:
        unique_together = ("follower", "following")
        constraints = [
            models.CheckConstraint(
                check=~models.Q(follower=models.F("following")),
                name="follow_no_self_follow",
            )
        ]

    def __str__(self):
        return f"{self.follower} -> {self.following} ({self.status})"