from typing import ClassVar
from uuid import uuid4

from django.contrib.auth.models import AbstractBaseUser, PermissionsMixin
from django.db.models import (
	AutoField,
	BooleanField,
	CASCADE,
	CharField,
	DateField,
	DateTimeField,
	EmailField,
	UUIDField,
	Model,
	OneToOneField,
	TextField,
	UniqueConstraint,
	URLField,
)
from django.conf import settings
from django.utils.translation import gettext_lazy as _

from apps.users.managers import UserManager


class TimeStampMixin(Model):
	"""Abstract model that provides created_at and updated_at fields."""

	created_at = DateTimeField(verbose_name="Created At", auto_now_add=True)
	updated_at = DateTimeField(verbose_name="Updated At", auto_now=True)

	class Meta:
		abstract = True


class User(AbstractBaseUser, TimeStampMixin, PermissionsMixin):
	"""Default custom user model for viswamedha.com (adapted).

	Uses username as the USERNAME_FIELD and maintains an email_address
	field used as the primary contact address.
	"""

	id = AutoField(primary_key=True)
	user_uuid = UUIDField(verbose_name=_("User UUID"), default=uuid4, editable=False)

	# Required fields
	email_address = EmailField(verbose_name=_("Email Address"), max_length=255, unique=True)
	username = CharField(verbose_name=_("Username"), max_length=25, unique=True)
	first_name = CharField(verbose_name=_("First Name"), max_length=255)
	last_name = CharField(verbose_name=_("Last Name"), max_length=255)
	date_of_birth = DateField(verbose_name=_("Date of Birth"), null=True, blank=True)

	is_active = BooleanField(verbose_name=_("Account Active"), default=True)
	is_staff = BooleanField(verbose_name=_("Account Admin"), default=False)
	is_verified = BooleanField(verbose_name=_("Account Verified"), default=False)


	USERNAME_FIELD = 'username'
	EMAIL_FIELD = 'email_address'
	REQUIRED_FIELDS = ['email_address', 'first_name', 'last_name', 'date_of_birth']

	objects: ClassVar[UserManager] = UserManager()

	def has_perm(self, perm, obj=None):
		return True

	def has_module_perms(self, app_label):
		return True

	class Meta:
		verbose_name = _('User')
		verbose_name_plural = _('Users')
		constraints = [
			UniqueConstraint(fields=['username'], name='unique_username'),
		]

	@property
	def full_name(self):
		return f"{self.first_name} {self.last_name}"

	@property
	def is_student(self):
		return hasattr(self, 'student')

	def __str__(self):
		return self.full_name

	def save(self, *args, **kwargs):
		if self.username:
			self.username = self.username.lower()
		super().save(*args, **kwargs)


class UserProfile(Model):
	"""A lightweight profile attached to the project's `AUTH_USER_MODEL`."""

	user = OneToOneField(
		settings.AUTH_USER_MODEL, on_delete=CASCADE, related_name='profile'
	)
	display_name = CharField(max_length=150, blank=True)
	bio = TextField(blank=True)
	timezone = CharField(max_length=64, blank=True)
	avatar_url = URLField(blank=True)
	created_at = DateTimeField(auto_now_add=True)
	updated_at = DateTimeField(auto_now=True)

	def __str__(self) -> str:  # pragma: no cover - trivial
		return self.display_name or getattr(self.user, 'username', str(self.user))