import uuid
from datetime import timedelta

from django.conf import settings
from django.contrib.auth.models import AbstractBaseUser, PermissionsMixin, BaseUserManager
from django.db import models
from django.utils import timezone


class UserRole(models.TextChoices):
    ADMIN = "admin", "Admin"
    MANAGER = "manager", "Salon Manager"
    STAFF = "staff", "Staff"
    CUSTOMER = "customer", "Customer"


class UserManager(BaseUserManager):
    def create_user(self, email=None, password=None, **extra_fields):
        phone_number = extra_fields.get("phone_number")
        if not email and not phone_number:
            raise ValueError("Email or phone number is required")
        if email:
            email = self.normalize_email(email)
        user = self.model(email=email, **extra_fields)
        if password:
            user.set_password(password)
        else:
            user.set_unusable_password()
        user.save(using=self._db)
        return user

    def create_superuser(self, phone_number, password=None, **extra_fields):
        extra_fields.setdefault("is_staff", True)
        extra_fields.setdefault("is_superuser", True)
        extra_fields.setdefault("role", UserRole.ADMIN)
        if extra_fields.get("is_staff") is not True:
            raise ValueError("Superuser must have is_staff=True")
        if extra_fields.get("is_superuser") is not True:
            raise ValueError("Superuser must have is_superuser=True")
        return self.create_user(phone_number=phone_number, password=password, **extra_fields)


class User(AbstractBaseUser, PermissionsMixin):
    email = models.EmailField(unique=True, null=True, blank=True)
    phone_number = models.CharField(max_length=20, unique=True, null=True, blank=True)
    role = models.CharField(max_length=20, choices=UserRole.choices, default=UserRole.CUSTOMER)
    first_name = models.CharField(max_length=150, blank=True)
    last_name = models.CharField(max_length=150, blank=True)
    is_phone_verified = models.BooleanField(default=False)
    preferred_language = models.CharField(
        max_length=10,
        choices=settings.LANGUAGES,
        default=settings.LANGUAGE_CODE,
    )
    is_active = models.BooleanField(default=True)
    is_staff = models.BooleanField(default=False)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    objects = UserManager()

    USERNAME_FIELD = "phone_number"
    REQUIRED_FIELDS = []  # email is optional; phone_number is the identifier

    def __str__(self):
        return self.email or self.phone_number or str(self.id)


class OtpChannel(models.TextChoices):
    SMS = "sms", "SMS"
    WHATSAPP = "whatsapp", "WhatsApp"


class OtpPurpose(models.TextChoices):
    AUTH = "auth", "Authentication"
    VERIFY = "verify", "Phone Verification"


class PhoneOTP(models.Model):
    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    phone_number = models.CharField(max_length=20)
    channel = models.CharField(max_length=20, choices=OtpChannel.choices)
    purpose = models.CharField(max_length=20, choices=OtpPurpose.choices, default=OtpPurpose.AUTH)
    provider = models.CharField(max_length=50)
    code_hash = models.CharField(max_length=128)
    created_at = models.DateTimeField(auto_now_add=True)
    expires_at = models.DateTimeField()
    verified_at = models.DateTimeField(null=True, blank=True)
    attempt_count = models.PositiveSmallIntegerField(default=0)
    max_attempts = models.PositiveSmallIntegerField(default=5)

    def is_expired(self):
        return timezone.now() >= self.expires_at

    @classmethod
    def expiry_at(cls):
        return timezone.now() + timedelta(minutes=settings.OTP_EXPIRY_MINUTES)