feat: add profit and special discount fields to ProductVariant model

- Updated ProductVariant model to include 'profit' and 'special_discount_percent' fields.
- Added corresponding fields in the admin interface for ProductVariant.
- Created migration to add new fields to the database.

feat: implement special discount code functionality in cart

- Added composables for submitting and deleting special discount codes.
- Updated CartSummary and CartItem components to handle special discount codes.
- Enhanced API endpoints to support special discount operations.
- Updated global types to include special discount code details in the cart.

backend/order/models.py

@@ -1,3 +1,4 @@
+from account.models import SpecialDiscountCode
 from django.db import models, transaction
 from account.models import User, UserAddressModel, PushSubscription
 from product.models import ProductModel, ProductVariant, ProductImageModel
@@ -47,6 +48,8 @@ class Cart(models.Model):
                                 related_name='carts', null=True, verbose_name='ادرس')
     discount_code = models.ForeignKey(
         DiscountCode, on_delete=models.PROTECT, null=True, blank=True, verbose_name="کدتخفیف")
+    special_discount_code = models.ForeignKey(
+        SpecialDiscountCode, on_delete=models.PROTECT, null=True, blank=True, verbose_name="کدتخفیف خاص")
 
     class Meta:
         verbose_name = 'سبد خرید'
@@ -58,6 +61,7 @@ class Cart(models.Model):
     def clear_cart(self):
         self.items.all().delete()
         self.discount_code = None
+        self.special_discount_code = None
         self.save()
 
     @property
@@ -71,10 +75,17 @@ class Cart(models.Model):
     def items_discount_amount(self):
         return int(sum(item.item_discount_amount for item in self.items.all()))
 
+    @property
+    def special_discount_total(self):
+        """Sum of all special discounts from cart items when special_discount_code is applied."""
+        if self.special_discount_code:
+            return int(sum(item.item_special_discount_amount for item in self.items.all()))
+        return 0
+
     @property
     def total_before_tax(self):
-        return self.cart_total - (self.discount_code_amount + self.items_discount_amount)
-    
+        return self.cart_total - (self.discount_code_amount + self.items_discount_amount + self.special_discount_total)
+
     @property
     def tax_amount(self):
         return int(self.total_before_tax * settings.DEFAULT_TAX_RATE / 100)
@@ -102,6 +113,7 @@ class CartItem(models.Model):
     quantity = models.PositiveIntegerField(default=1)
     created_at = models.DateTimeField(auto_now_add=True)
     updated_at = models.DateTimeField(auto_now=True)
+    # special_discount_amount = models.BigIntegerField(default=0, verbose_name='مقدار تخفیف ویژه', help_text='تخفیف محاسبه شده از سود تنوع')
 
     class Meta:
         verbose_name = 'ایتم سبد خرید'
@@ -111,22 +123,37 @@ class CartItem(models.Model):
     def __str__(self):
         return f"{self.quantity} x {self.product_variant.product.name} in cart {self.cart.id}"
 
+    @property
+    def special_discount_amount(self):
+        """Calculate special discount for this cart item based on variant profit and special_discount_percent."""
+        if hasattr(self.cart, 'special_discount_code') and self.cart.special_discount_code:
+            return self.product_variant.special_discount_amount_per_unit * self.quantity
+        return 0
+
     @property
     def price_before_discount(self):
         return self.quantity * self.product_variant.price_before_discount
-    
+
     @property
     def item_discount_amount(self):
         return self.product_variant.discount_amount * self.quantity
-    
+
+    @property
+    def item_special_discount_amount(self):
+        """Calculate special discount for this cart item based on variant profit and special_discount_percent."""
+        if hasattr(self.cart, 'special_discount_code') and self.cart.special_discount_code:
+            return self.product_variant.special_discount_amount_per_unit * self.quantity
+        return 0
+
     @property
     def price_after_discount(self):
-        return self.price_before_discount - self.item_discount_amount
+        return self.price_before_discount - self.item_discount_amount - self.item_special_discount_amount
 
     @property
     def discount(self):
         return self.product_variant.discount
 
+
 class OrderModel(models.Model):
     objects = jmodels.jManager()
     STATUS_CHOICES = [
@@ -155,9 +182,12 @@ class OrderModel(models.Model):
         null=True, blank=True, verbose_name='قیمت نهایی')
     cart_total = models.BigIntegerField(
         null=True, blank=True, verbose_name='کل سبد خرید')
+    special_discount_total = models.BigIntegerField(
+        null=True, blank=True, verbose_name='مجموع تخفیف ویژه')
+
+    cart = models.ForeignKey(
+        Cart, on_delete=models.CASCADE, null=True, blank=True)
 
-    cart = models.ForeignKey(Cart, on_delete=models.CASCADE, null=True, blank=True)
-    
     is_stock_rolled_back = models.BooleanField(
         default=False, verbose_name="موجودی برگردانده شده")
 
@@ -169,36 +199,37 @@ class OrderModel(models.Model):
         verbose_name_plural = 'سفارشات'
 
     def rollback_stock(self):
-            """
-            Rollback stock quantities for all items in this order
-            Returns True if successful, False otherwise
-            """
-            if self.is_stock_rolled_back:
-                return False
-            
-            # if not self.cart:
-            #     return False
-            
-            try:
-                # Get all cart items and rollback their stock
-                for order_item in self.items.all():
-                    product = order_item.product
-                    # Add back the quantity to stock
-                    product.in_stock += order_item.quantity
-                    product.save()
-                
-                # Mark as rolled back
-                self.is_stock_rolled_back = True
-                self.save(update_fields=['is_stock_rolled_back'])
-                self.status = 'CANCELED'
-                self.save()
-                return True
-                
-            except Exception as e:
-                print(e)
-                # Log the error if you have logging setup
-                # logger.error(f"Failed to rollback stock for order {self.pk}: {e}")
-                return False
+        """
+        Rollback stock quantities for all items in this order
+        Returns True if successful, False otherwise
+        """
+        if self.is_stock_rolled_back:
+            return False
+
+        # if not self.cart:
+        #     return False
+
+        try:
+            # Get all cart items and rollback their stock
+            for order_item in self.items.all():
+                product = order_item.product
+                # Add back the quantity to stock
+                product.in_stock += order_item.quantity
+                product.save()
+
+            # Mark as rolled back
+            self.is_stock_rolled_back = True
+            self.save(update_fields=['is_stock_rolled_back'])
+            self.status = 'CANCELED'
+            self.save()
+            return True
+
+        except Exception as e:
+            print(e)
+            # Log the error if you have logging setup
+            # logger.error(f"Failed to rollback stock for order {self.pk}: {e}")
+            return False
+
 
 class OrderItemModel(models.Model):
     order = models.ForeignKey(
@@ -208,6 +239,8 @@ class OrderItemModel(models.Model):
     product = models.ForeignKey(
         ProductVariant, on_delete=models.PROTECT, verbose_name="محصول")
     discount_percent = models.SmallIntegerField(verbose_name='درصد تخفیف')
+    special_discount_amount = models.BigIntegerField(
+        default=0, verbose_name='مقدار تخفیف ویژه')
 
     class Meta:
         verbose_name = 'ایتم سبد خرید'