Andrey Smakotin
f57e639dbe
Добавлено поле combine_mode с тремя режимами: - stack - складывать с другими скидками - max_only - применять только максимальную - exclusive - отменяет все остальные скидки Изменения: - Модель Discount: добавлено поле combine_mode - Calculator: новый класс DiscountCombiner, методы возвращают списки скидок - Applier: создание нескольких DiscountApplication записей - Admin: отображение combine_mode с иконками - POS API: возвращает списки применённых скидок - POS UI: отображение нескольких скидок с иконками режимов Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
314 lines
12 KiB
Python
314 lines
12 KiB
Python
from decimal import Decimal
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from django.db import transaction
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from django.core.exceptions import ValidationError
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class DiscountApplier:
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"""
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Сервис для применения скидок к заказам.
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Поддерживает комбинирование скидок по combine_mode.
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Все операции атомарны.
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"""
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@staticmethod
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@transaction.atomic
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def apply_promo_code(order, promo_code, user=None):
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"""
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Применить промокод к заказу.
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Поддерживает комбинирование скидок.
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Args:
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order: Order
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promo_code: str
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user: CustomUser (применивший скидку)
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Returns:
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dict: {
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'success': bool,
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'discounts': [{'discount': Discount, 'amount': Decimal}, ...],
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'total_amount': Decimal,
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'error': str
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}
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"""
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from discounts.models import PromoCode, DiscountApplication
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from discounts.services.calculator import DiscountCalculator
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# Удаляем предыдущую скидку на заказ
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if order.applied_promo_code:
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DiscountApplier._remove_order_discount_only(order)
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# Рассчитываем скидку
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result = DiscountCalculator.calculate_order_discount(order, promo_code)
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if result['error']:
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return {
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'success': False,
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'error': result['error']
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}
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promo = result['promo_code']
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discounts_data = result['discounts']
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total_amount = result['total_amount']
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# Применяем первую скидку в applied_discount (для обратной совместимости с Order)
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if discounts_data:
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first_discount = discounts_data[0]['discount']
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order.applied_discount = first_discount
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order.applied_promo_code = promo.code
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order.discount_amount = total_amount
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order.save(update_fields=['applied_discount', 'applied_promo_code', 'discount_amount'])
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# Пересчитываем total_amount
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order.calculate_total()
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# Регистрируем использование промокода
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promo.record_usage(order.customer)
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# Создаем записи о применении для каждой скидки
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for disc_data in discounts_data:
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discount = disc_data['discount']
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amount = disc_data['amount']
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DiscountApplication.objects.create(
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order=order,
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discount=discount,
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promo_code=promo,
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target='order',
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base_amount=order.subtotal,
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discount_amount=amount,
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final_amount=order.subtotal - amount,
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customer=order.customer,
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applied_by=user or order.modified_by
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)
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# Увеличиваем счетчик использований скидки
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discount.current_usage_count += 1
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discount.save(update_fields=['current_usage_count'])
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return {
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'success': True,
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'discounts': discounts_data,
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'total_amount': total_amount
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}
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@staticmethod
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@transaction.atomic
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def apply_auto_discounts(order, user=None):
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"""
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Применить автоматические скидки к заказу и позициям.
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Поддерживает комбинирование скидок.
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Args:
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order: Order
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user: CustomUser
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Returns:
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dict: {
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'order_discounts': [...],
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'item_discounts': [...],
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'total_discount': Decimal
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}
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"""
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from discounts.models import Discount, DiscountApplication
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from discounts.services.calculator import DiscountCalculator
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result = {
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'order_discounts': [],
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'item_discounts': [],
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'total_discount': Decimal('0')
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}
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# 1. Применяем скидки на заказ (может быть несколько)
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order_result = DiscountCalculator.calculate_order_discount(order)
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if order_result['discounts'] and not order_result['error']:
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total_order_amount = order_result['total_amount']
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# Сохраняем первую скидку в applied_discount (для совместимости)
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first_discount_data = order_result['discounts'][0]
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order.applied_discount = first_discount_data['discount']
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order.discount_amount = total_order_amount
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order.save(update_fields=['applied_discount', 'discount_amount'])
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# Создаем записи о применении для всех скидок
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for disc_data in order_result['discounts']:
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discount = disc_data['discount']
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amount = disc_data['amount']
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DiscountApplication.objects.create(
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order=order,
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discount=discount,
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target='order',
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base_amount=order.subtotal,
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discount_amount=amount,
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final_amount=order.subtotal - amount,
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customer=order.customer,
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applied_by=user
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)
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# Увеличиваем счетчик
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discount.current_usage_count += 1
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discount.save(update_fields=['current_usage_count'])
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result['order_discounts'] = order_result['discounts']
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result['total_discount'] += total_order_amount
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# 2. Применяем скидки на позиции
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available_product_discounts = list(DiscountCalculator.get_available_discounts(
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scope='product',
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auto_only=True
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))
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for item in order.items.all():
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item_result = DiscountCalculator.calculate_item_discount(
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item, available_product_discounts
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)
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if item_result['discounts']:
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total_item_amount = item_result['total_amount']
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# Сохраняем первую скидку в applied_discount (для совместимости)
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first_discount_data = item_result['discounts'][0]
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item.applied_discount = first_discount_data['discount']
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item.discount_amount = total_item_amount
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item.save(update_fields=['applied_discount', 'discount_amount'])
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# Создаем записи о применении для всех скидок
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base_amount = item.price * item.quantity
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for disc_data in item_result['discounts']:
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discount = disc_data['discount']
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amount = disc_data['amount']
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DiscountApplication.objects.create(
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order=order,
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order_item=item,
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discount=discount,
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target='order_item',
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base_amount=base_amount,
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discount_amount=amount,
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final_amount=item.get_total_price(),
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customer=order.customer,
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applied_by=user
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)
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# Увеличиваем счетчик
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discount.current_usage_count += 1
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discount.save(update_fields=['current_usage_count'])
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result['item_discounts'].append({
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'item': item,
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'discounts': item_result['discounts'],
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'total_amount': total_item_amount
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})
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result['total_discount'] += total_item_amount
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# Пересчитываем итоговую сумму
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order.calculate_total()
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return result
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@staticmethod
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@transaction.atomic
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def remove_discount_from_order(order):
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"""
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Удалить скидку с заказа.
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Args:
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order: Order
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"""
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DiscountApplier._remove_order_discount_only(order)
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# Удаляем скидки с позиций
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order.items.update(
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applied_discount=None,
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discount_amount=Decimal('0')
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)
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# Удаляем записи о применении
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from discounts.models import DiscountApplication
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DiscountApplication.objects.filter(order=order).delete()
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# Пересчитываем
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order.calculate_total()
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@staticmethod
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@transaction.atomic
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def apply_manual_discount(order, discount, user=None):
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"""
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Применить скидку вручную к заказу.
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Args:
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order: Order
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discount: Discount
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user: CustomUser (применивший скидку)
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Returns:
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dict: {
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'success': bool,
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'discount_amount': Decimal,
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'error': str
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}
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"""
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from discounts.models import DiscountApplication
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# Проверяем scope скидки
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if discount.scope != 'order':
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return {'success': False, 'error': 'Эта скидка не применяется к заказу'}
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# Проверяем мин. сумму
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if discount.min_order_amount and order.subtotal < discount.min_order_amount:
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return {'success': False, 'error': f'Мин. сумма заказа: {discount.min_order_amount} руб.'}
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# Удаляем предыдущую скидку на заказ
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DiscountApplier._remove_order_discount_only(order)
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# Рассчитываем сумму
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discount_amount = discount.calculate_discount_amount(Decimal(order.subtotal))
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# Применяем к заказу
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order.applied_discount = discount
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order.discount_amount = discount_amount
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order.save(update_fields=['applied_discount', 'discount_amount'])
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# Пересчитываем total_amount
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order.calculate_total()
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# Создаем запись о применении
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DiscountApplication.objects.create(
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order=order,
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discount=discount,
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target='order',
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base_amount=order.subtotal,
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discount_amount=discount_amount,
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final_amount=order.subtotal - discount_amount,
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customer=order.customer,
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applied_by=user
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)
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# Увеличиваем счетчик использований скидки
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discount.current_usage_count += 1
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discount.save(update_fields=['current_usage_count'])
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return {
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'success': True,
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'discount_amount': discount_amount
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}
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@staticmethod
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def _remove_order_discount_only(order):
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"""
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Удалить только скидку с заказа (не трогая позиции).
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Args:
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order: Order
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"""
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from discounts.models import DiscountApplication
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# Удаляем записи о применении скидок к заказу
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DiscountApplication.objects.filter(order=order, target='order').delete()
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order.applied_discount = None
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order.applied_promo_code = None
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order.discount_amount = Decimal('0')
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order.save(update_fields=['applied_discount', 'applied_promo_code', 'discount_amount'])
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