from django.db import models, transaction
from account.models import User, UserAddressModel, PushSubscription
from product.models import ProductModel, ProductVariant, ProductImageModel
from django.utils import timezone
from django_jalali.db import models as jmodels
from django.core.exceptions import ValidationError
from django.conf import settings

class DiscountCode(models.Model):
    code = models.CharField(max_length=50, verbose_name='کد تخفیف')
    percent = models.DecimalField(max_digits=4, decimal_places=2, verbose_name='درصد')
    quantity = models.PositiveIntegerField(verbose_name='تعداد')
    expiration_date = models.DateTimeField(verbose_name='تاریخ انقضا')

    def __str__(self):
        return self.code

    class Meta:
        verbose_name = 'کد تخفیف'
        verbose_name_plural = 'کد های تخفیف'

    def is_valid(self):
        return self.expiration_date > timezone.now() and self.quantity > 0

    def not_valid_reason(self):
        if self.expiration_date > timezone.now() and self.quantity > 0:
            return 'این کد معتبر میباشد'
        elif not self.expiration_date > timezone.now():
            return 'تایم کد تخفیف تمام شده'
        elif not self.quantity > 0:
            return 'این کد تخفیف تمام شده است'
        else:
            print('log later bug')



class OrderModel(models.Model):
    objects = jmodels.jManager()
    STATUS_CHOICES = [
        ('CART', 'در سبد خرید'),
        ('ADMIN_PENDING', 'در انتظار تایید'),
        ('PENDING', 'درحال پردازش'),
        ('POSTED', 'ارسال شده'),
        ('RECEIVED', 'تحویل شده'),
        ('CANCELED', 'لغو شده'),
        ('REFUNDED', 'مرجوع شده'),
    ]
    user = models.ForeignKey(User, on_delete=models.SET_NULL, null=True, related_name='orders', verbose_name='کاربر')
    address = models.ForeignKey(UserAddressModel, on_delete=models.SET_NULL, related_name='orders', null=True, verbose_name='ادرس')
    created_at = jmodels.jDateField(blank=True, null=True, verbose_name="تاریخ ثبت سفارش")    
    is_paid = models.BooleanField(default=False, verbose_name="وضعیت پرداخت")
    discount_code = models.ForeignKey(DiscountCode, on_delete=models.PROTECT, null=True, blank=True, verbose_name="کدتخفیف")
    status = models.CharField(max_length=20, choices=STATUS_CHOICES, default='CART', verbose_name="وضعیت سفارش")
    discount_amount = models.BigIntegerField(null=True, blank=True, verbose_name='مقدار کد تخفیف')
    tax = models.BigIntegerField(null=True, blank=True, verbose_name='مالیات')
    final_price = models.BigIntegerField(null=True, blank=True, verbose_name='قیمت نهایی')
    cart_total = models.BigIntegerField(null=True, blank=True, verbose_name='کل سبد خرید')
    
    def __str__(self):
        return f'سفارش: {self.pk + 1000}'

    class Meta:
        verbose_name = 'سفارش'
        verbose_name_plural = 'سفارشات'



    def _cal_discount_amount(self, cart_total):
        discount_percent = self.discount_code.percent if self.discount_code else 0
        return int(cart_total * discount_percent / 100)

    def _cal_tax(self, cart_total, discount_amount):
        tax_rate = getattr(settings, 'DEFAULT_TAX_RATE', 20)
        return int((cart_total - discount_amount) * tax_rate / 100)
    
    def _cal_cart_total(self):
        from django.db.models import Sum, F, FloatField
        return self.items.aggregate(
            total=Sum(F('price') * (1 - F('discount_percent')/100) * F('quantity'),
            output_field=FloatField()
        )).get('total') or 0

    def _cal_final_price(self, cart_total, discount_amount, tax):
        return cart_total - discount_amount + tax

    def update_order(self):
        if self.status == 'CART':
            cart_total = self._cal_cart_total()
            discount_amount = self._cal_discount_amount(cart_total)
            self.discount_amount = discount_amount
            self.cart_total = cart_total
            tax = self._cal_tax(cart_total, discount_amount)
            self.tax = tax
            self.final_price = self._cal_final_price(cart_total, discount_amount, tax)
            self.save()
        else:
            pass


class OrderItemModel(models.Model):
    order = models.ForeignKey(OrderModel, on_delete=models.CASCADE, related_name='items', verbose_name='سفارش')
    quantity = models.PositiveSmallIntegerField(verbose_name="تعداد")
    price = models.BigIntegerField(verbose_name='قیمت')
    product = models.ForeignKey(ProductVariant, on_delete=models.PROTECT, verbose_name="محصول")
    discount_percent = models.SmallIntegerField(verbose_name='درصد تخفیف')
    class Meta:
        verbose_name = 'ایتم سبد خرید'
        verbose_name_plural = 'ایتم های سبد خرید'


    def set_or_update_fields(self):
        self.price = self.product.price
        self.discount_percent = self.product.discount

    def __str__(self):
        return f'({self.product}) - ({self.order.user})'

    def save(self, *args, **kwargs):
        self.clean()
        self.set_or_update_fields()
        super().save(*args, **kwargs)
        self.order.update_order()

    def delete(self, *args, **kwargs):
        self.clean()
        order = self.order
        super().delete(*args, **kwargs)
        order.update_order()

    def clean(self):
        if self.pk and self.order.status != "CART":
            raise ValidationError("ایتم ها فقط در حالت سبد خرید قابل ادیت هستند")