from django.contrib.auth.models import AbstractUser
from django.db import models
from django.db.models.signals import post_save
from django.dispatch import receiver

class User(AbstractUser):
    pass

class Profile(models.Model):
    THEME_CHOICES = (
        ('light', 'Light'),
        ('dark', 'Dark'),
        ('compact', 'Compact'),
        ('expressive', 'Expressive'),
        ('technical', 'Technical'),
    )

    user = models.OneToOneField(User, on_delete=models.CASCADE, related_name='profile')
    is_pro = models.BooleanField(default=False)
    is_seller = models.BooleanField(default=False)
    theme_preference = models.CharField(max_length=10, choices=THEME_CHOICES, default='dark')
    # Keeping this simple text field for legacy/simple addressing, whilst adding robust Address model below
    shipping_address = models.TextField(blank=True)
    stripe_customer_id = models.CharField(max_length=100, blank=True, null=True)

    def __str__(self):
        return self.user.username

@receiver(post_save, sender=User)
def create_user_profile(sender, instance, created, **kwargs):
    if created:
        Profile.objects.create(user=instance)

@receiver(post_save, sender=User)
def save_user_profile(sender, instance, **kwargs):
    instance.profile.save()

class Address(models.Model):
    ADDRESS_TYPE_CHOICES = (
        ('shipping', 'Shipping'),
        ('billing', 'Billing'),
    )

    user = models.ForeignKey(User, on_delete=models.CASCADE, related_name='addresses')
    name = models.CharField(max_length=100)
    street = models.CharField(max_length=200)
    city = models.CharField(max_length=100)
    state = models.CharField(max_length=100)
    zip_code = models.CharField(max_length=20)
    address_type = models.CharField(max_length=20, choices=ADDRESS_TYPE_CHOICES, default='shipping')
    is_default = models.BooleanField(default=False)

    def __str__(self):
        return f"{self.name} - {self.street}"

class PaymentMethod(models.Model):
    user = models.ForeignKey(User, on_delete=models.CASCADE, related_name='payment_methods')
    billing_address = models.ForeignKey(Address, on_delete=models.SET_NULL, null=True, blank=True, related_name='payment_methods')
    
    brand = models.CharField(max_length=50) # Visa, Mastercard
    last4 = models.CharField(max_length=4)
    exp_month = models.PositiveIntegerField()
    exp_year = models.PositiveIntegerField()
    is_default = models.BooleanField(default=False)
    
    # Encrypted fields
    card_number_encrypted = models.BinaryField(blank=True, null=True)
    cvv_encrypted = models.BinaryField(blank=True, null=True)

    @property
    def card_number(self):
        try:
            from store.utils import Encryptor
            return Encryptor.decrypt(self.card_number_encrypted)
        except ImportError:
            # Fallback if store isn't ready or circular import
            return None

    @card_number.setter
    def card_number(self, value):
        from store.utils import Encryptor
        self.card_number_encrypted = Encryptor.encrypt(value)
        if value and len(str(value)) >= 4:
            self.last4 = str(value)[-4:]

    @property
    def cvv(self):
        from store.utils import Encryptor
        return Encryptor.decrypt(self.cvv_encrypted)

    @cvv.setter
    def cvv(self, value):
        from store.utils import Encryptor
        self.cvv_encrypted = Encryptor.encrypt(value)
    
    def __str__(self):
        return f"{self.brand} ending in {self.last4}"

class Buyer(models.Model):
    user = models.OneToOneField(User, on_delete=models.CASCADE, related_name='buyer_profile')
    created_at = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return self.user.username

@receiver(post_save, sender=User)
def create_buyer_profile(sender, instance, created, **kwargs):
    # We only auto-create Buyer if NOT a seller? 
    # Or do we create it manually in views?
    # The requirement says "/user/register creates a buy account and /sell/register creates a seller account"
    # So we probably shouldn't auto-create blindly for EVERY user if we want them distinct.
    # However, easy way is to create it manually in the view.
    # I will NOT add a signal here to avoid auto-creation when we might want a pure Seller.
    pass