From c070e42cabb2520021dd932ebffdfc801dd38590 Mon Sep 17 00:00:00 2001
From: Andrey Smakotin <slamfromm@gmail.com>
Date: Sun, 11 Jan 2026 13:46:02 +0300
Subject: [PATCH] =?UTF-8?q?feat(discounts,=20orders):=20=D1=80=D0=B5=D1=84?=
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- Добавлен combine_mode в форму создания/редактирования скидок
- Добавлена колонка "Объединение" в список скидок с иконками
- Добавлен фильтр по режиму объединения скидок
- Добавлена валидация: только одна exclusive скидка на заказ
- Удалены дублирующие поля из Order и OrderItem:
  - applied_discount, applied_promo_code, discount_amount
- Скидки теперь хранятся только в DiscountApplication
- Добавлены свойства для обратной совместимости

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
---
 myproject/discounts/services/applier.py       | 64 ++++--------------
 .../templates/discounts/discount_form.html    | 16 +++++
 .../templates/discounts/discount_list.html    | 27 ++++++--
 myproject/discounts/views.py                  | 38 ++++++++++-
 myproject/orders/admin.py                     | 12 +---
 .../0004_remove_old_discount_fields.py        | 33 ++++++++++
 myproject/orders/models/order.py              | 66 ++++++++++++-------
 myproject/orders/models/order_item.py         | 40 ++++++-----
 myproject/pos/views.py                        |  8 +--
 9 files changed, 192 insertions(+), 112 deletions(-)
 create mode 100644 myproject/orders/migrations/0004_remove_old_discount_fields.py

diff --git a/myproject/discounts/services/applier.py b/myproject/discounts/services/applier.py
index f4cc175..7e3fa91 100644
--- a/myproject/discounts/services/applier.py
+++ b/myproject/discounts/services/applier.py
@@ -34,8 +34,7 @@ class DiscountApplier:
         from discounts.services.calculator import DiscountCalculator
 
         # Удаляем предыдущую скидку на заказ
-        if order.applied_promo_code:
-            DiscountApplier._remove_order_discount_only(order)
+        DiscountApplier._remove_order_discount_only(order)
 
         # Рассчитываем скидку
         result = DiscountCalculator.calculate_order_discount(order, promo_code)
@@ -50,21 +49,7 @@ class DiscountApplier:
         discounts_data = result['discounts']
         total_amount = result['total_amount']
 
-        # Применяем первую скидку в applied_discount (для обратной совместимости с Order)
-        if discounts_data:
-            first_discount = discounts_data[0]['discount']
-            order.applied_discount = first_discount
-            order.applied_promo_code = promo.code
-            order.discount_amount = total_amount
-            order.save(update_fields=['applied_discount', 'applied_promo_code', 'discount_amount'])
-
-        # Пересчитываем total_amount
-        order.calculate_total()
-
-        # Регистрируем использование промокода
-        promo.record_usage(order.customer)
-
-        # Создаем записи о применении для каждой скидки
+        # Создаем записи о применении для каждой скидки в DiscountApplication
         for disc_data in discounts_data:
             discount = disc_data['discount']
             amount = disc_data['amount']
@@ -85,6 +70,12 @@ class DiscountApplier:
             discount.current_usage_count += 1
             discount.save(update_fields=['current_usage_count'])
 
+        # Пересчитываем total_amount (использует DiscountApplication)
+        order.calculate_total()
+
+        # Регистрируем использование промокода
+        promo.record_usage(order.customer)
+
         return {
             'success': True,
             'discounts': discounts_data,
@@ -124,12 +115,6 @@ class DiscountApplier:
         if order_result['discounts'] and not order_result['error']:
             total_order_amount = order_result['total_amount']
 
-            # Сохраняем первую скидку в applied_discount (для совместимости)
-            first_discount_data = order_result['discounts'][0]
-            order.applied_discount = first_discount_data['discount']
-            order.discount_amount = total_order_amount
-            order.save(update_fields=['applied_discount', 'discount_amount'])
-
             # Создаем записи о применении для всех скидок
             for disc_data in order_result['discounts']:
                 discount = disc_data['discount']
@@ -167,12 +152,6 @@ class DiscountApplier:
             if item_result['discounts']:
                 total_item_amount = item_result['total_amount']
 
-                # Сохраняем первую скидку в applied_discount (для совместимости)
-                first_discount_data = item_result['discounts'][0]
-                item.applied_discount = first_discount_data['discount']
-                item.discount_amount = total_item_amount
-                item.save(update_fields=['applied_discount', 'discount_amount'])
-
                 # Создаем записи о применении для всех скидок
                 base_amount = item.price * item.quantity
                 for disc_data in item_result['discounts']:
@@ -186,7 +165,7 @@ class DiscountApplier:
                         target='order_item',
                         base_amount=base_amount,
                         discount_amount=amount,
-                        final_amount=item.get_total_price(),
+                        final_amount=base_amount - amount,
                         customer=order.customer,
                         applied_by=user
                     )
@@ -216,14 +195,6 @@ class DiscountApplier:
         Args:
             order: Order
         """
-        DiscountApplier._remove_order_discount_only(order)
-
-        # Удаляем скидки с позиций
-        order.items.update(
-            applied_discount=None,
-            discount_amount=Decimal('0')
-        )
-
         # Удаляем записи о применении
         from discounts.models import DiscountApplication
         DiscountApplication.objects.filter(order=order).delete()
@@ -265,14 +236,6 @@ class DiscountApplier:
         # Рассчитываем сумму
         discount_amount = discount.calculate_discount_amount(Decimal(order.subtotal))
 
-        # Применяем к заказу
-        order.applied_discount = discount
-        order.discount_amount = discount_amount
-        order.save(update_fields=['applied_discount', 'discount_amount'])
-
-        # Пересчитываем total_amount
-        order.calculate_total()
-
         # Создаем запись о применении
         DiscountApplication.objects.create(
             order=order,
@@ -289,6 +252,9 @@ class DiscountApplier:
         discount.current_usage_count += 1
         discount.save(update_fields=['current_usage_count'])
 
+        # Пересчитываем total_amount
+        order.calculate_total()
+
         return {
             'success': True,
             'discount_amount': discount_amount
@@ -307,7 +273,5 @@ class DiscountApplier:
         # Удаляем записи о применении скидок к заказу
         DiscountApplication.objects.filter(order=order, target='order').delete()
 
-        order.applied_discount = None
-        order.applied_promo_code = None
-        order.discount_amount = Decimal('0')
-        order.save(update_fields=['applied_discount', 'applied_promo_code', 'discount_amount'])
+        # Пересчитываем (order.discount_amount теперь свойство, берущее из DiscountApplication)
+        order.calculate_total()
diff --git a/myproject/discounts/templates/discounts/discount_form.html b/myproject/discounts/templates/discounts/discount_form.html
index 7ea29db..01a0cc7 100644
--- a/myproject/discounts/templates/discounts/discount_form.html
+++ b/myproject/discounts/templates/discounts/discount_form.html
@@ -101,6 +101,22 @@
                         </div>
                     </div>
 
+                    <div class="mb-3">
+                        <label for="id_combine_mode" class="form-label">Режим объединения с другими скидками</label>
+                        <select class="form-select" id="id_combine_mode" name="combine_mode">
+                            <option value="max_only" {% if form.combine_mode.value == 'max_only' or not form.combine_mode.value %}selected{% endif %}>
+                                🏆 Только максимум (применяется лучшая скидка)
+                            </option>
+                            <option value="stack" {% if form.combine_mode.value == 'stack' %}selected{% endif %}>
+                                📚 Складывать (суммировать с другими)
+                            </option>
+                            <option value="exclusive" {% if form.combine_mode.value == 'exclusive' %}selected{% endif %}>
+                                🚫 Исключающая (отменяет остальные скидки)
+                            </option>
+                        </select>
+                        <div class="form-text">Как эта скидка взаимодействует с другими активными скидками</div>
+                    </div>
+
                     <!-- Ограничения -->
                     <h5 class="mb-3 mt-4">Ограничения</h5>
                     <div class="row mb-3">
diff --git a/myproject/discounts/templates/discounts/discount_list.html b/myproject/discounts/templates/discounts/discount_list.html
index 7a2732a..f8f0bf6 100644
--- a/myproject/discounts/templates/discounts/discount_list.html
+++ b/myproject/discounts/templates/discounts/discount_list.html
@@ -60,6 +60,15 @@
                     <option value="inactive" {% if current_filters.is_active == 'inactive' %}selected{% endif %}>Неактивные</option>
                 </select>
             </div>
+            <div class="col-md-2">
+                <label class="form-label">Объединение</label>
+                <select name="combine_mode" class="form-select">
+                    <option value="">Все</option>
+                    <option value="stack" {% if current_filters.combine_mode == 'stack' %}selected{% endif %}>Складывать</option>
+                    <option value="max_only" {% if current_filters.combine_mode == 'max_only' %}selected{% endif %}>Максимум</option>
+                    <option value="exclusive" {% if current_filters.combine_mode == 'exclusive' %}selected{% endif %}>Исключающая</option>
+                </select>
+            </div>
             <div class="col-md-3 d-flex align-items-end">
                 <button type="submit" class="btn btn-primary me-2">
                     <i class="bi bi-funnel"></i> Применить
@@ -84,6 +93,7 @@
                         <th>Значение</th>
                         <th>Область</th>
                         <th>Авто</th>
+                        <th>Объединение</th>
                         <th>Статус</th>
                         <th>Промокоды</th>
                         <th>Использований</th>
@@ -129,6 +139,15 @@
                             <i class="bi bi-dash-circle text-muted"></i>
                             {% endif %}
                         </td>
+                        <td>
+                            {% if discount.combine_mode == 'stack' %}
+                            <span class="badge bg-secondary" title="Складывать (суммировать)">📚 Склад.</span>
+                            {% elif discount.combine_mode == 'max_only' %}
+                            <span class="badge bg-info" title="Только максимум">🏆 Макс.</span>
+                            {% elif discount.combine_mode == 'exclusive' %}
+                            <span class="badge bg-danger" title="Исключающая (отменяет остальные)">🚫 Исключ.</span>
+                            {% endif %}
+                        </td>
                         <td>
                             {% if discount.is_active %}
                             <span class="badge bg-success">Активна</span>
@@ -180,10 +199,10 @@
             <ul class="pagination justify-content-center">
                 {% if page_obj.has_previous %}
                 <li class="page-item">
-                    <a class="page-link" href="?page=1{% if current_filters.search %}&search={{ current_filters.search }}{% endif %}{% if current_filters.type %}&type={{ current_filters.type }}{% endif %}{% if current_filters.scope %}&scope={{ current_filters.scope }}{% endif %}{% if current_filters.is_active %}&is_active={{ current_filters.is_active }}{% endif %}">&laquo;</a>
+                    <a class="page-link" href="?page=1{% if current_filters.search %}&search={{ current_filters.search }}{% endif %}{% if current_filters.type %}&type={{ current_filters.type }}{% endif %}{% if current_filters.scope %}&scope={{ current_filters.scope }}{% endif %}{% if current_filters.is_active %}&is_active={{ current_filters.is_active }}{% endif %}{% if current_filters.combine_mode %}&combine_mode={{ current_filters.combine_mode }}{% endif %}">&laquo;</a>
                 </li>
                 <li class="page-item">
-                    <a class="page-link" href="?page={{ page_obj.previous_page_number }}{% if current_filters.search %}&search={{ current_filters.search }}{% endif %}{% if current_filters.type %}&type={{ current_filters.type }}{% endif %}{% if current_filters.scope %}&scope={{ current_filters.scope }}{% endif %}{% if current_filters.is_active %}&is_active={{ current_filters.is_active }}{% endif %}">&lsaquo;</a>
+                    <a class="page-link" href="?page={{ page_obj.previous_page_number }}{% if current_filters.search %}&search={{ current_filters.search }}{% endif %}{% if current_filters.type %}&type={{ current_filters.type }}{% endif %}{% if current_filters.scope %}&scope={{ current_filters.scope }}{% endif %}{% if current_filters.is_active %}&is_active={{ current_filters.is_active }}{% endif %}{% if current_filters.combine_mode %}&combine_mode={{ current_filters.combine_mode }}{% endif %}">&lsaquo;</a>
                 </li>
                 {% endif %}
 
@@ -193,10 +212,10 @@
 
                 {% if page_obj.has_next %}
                 <li class="page-item">
-                    <a class="page-link" href="?page={{ page_obj.next_page_number }}{% if current_filters.search %}&search={{ current_filters.search }}{% endif %}{% if current_filters.type %}&type={{ current_filters.type }}{% endif %}{% if current_filters.scope %}&scope={{ current_filters.scope }}{% endif %}{% if current_filters.is_active %}&is_active={{ current_filters.is_active }}{% endif %}">&rsaquo;</a>
+                    <a class="page-link" href="?page={{ page_obj.next_page_number }}{% if current_filters.search %}&search={{ current_filters.search }}{% endif %}{% if current_filters.type %}&type={{ current_filters.type }}{% endif %}{% if current_filters.scope %}&scope={{ current_filters.scope }}{% endif %}{% if current_filters.is_active %}&is_active={{ current_filters.is_active }}{% endif %}{% if current_filters.combine_mode %}&combine_mode={{ current_filters.combine_mode }}{% endif %}">&rsaquo;</a>
                 </li>
                 <li class="page-item">
-                    <a class="page-link" href="?page={{ page_obj.paginator.num_pages }}{% if current_filters.search %}&search={{ current_filters.search }}{% endif %}{% if current_filters.type %}&type={{ current_filters.type }}{% endif %}{% if current_filters.scope %}&scope={{ current_filters.scope }}{% endif %}{% if current_filters.is_active %}&is_active={{ current_filters.is_active }}{% endif %}">&raquo;</a>
+                    <a class="page-link" href="?page={{ page_obj.paginator.num_pages }}{% if current_filters.search %}&search={{ current_filters.search }}{% endif %}{% if current_filters.type %}&type={{ current_filters.type }}{% endif %}{% if current_filters.scope %}&scope={{ current_filters.scope }}{% endif %}{% if current_filters.is_active %}&is_active={{ current_filters.is_active }}{% endif %}{% if current_filters.combine_mode %}&combine_mode={{ current_filters.combine_mode }}{% endif %}">&raquo;</a>
                 </li>
                 {% endif %}
             </ul>
diff --git a/myproject/discounts/views.py b/myproject/discounts/views.py
index f7cf7e6..2702567 100644
--- a/myproject/discounts/views.py
+++ b/myproject/discounts/views.py
@@ -71,6 +71,7 @@ class DiscountListView(DiscountAccessMixin, ListView):
         discount_type = self.request.GET.get('type')
         scope = self.request.GET.get('scope')
         is_active = self.request.GET.get('is_active')
+        combine_mode = self.request.GET.get('combine_mode')
         search = self.request.GET.get('search')
 
         if discount_type:
@@ -79,6 +80,8 @@ class DiscountListView(DiscountAccessMixin, ListView):
             queryset = queryset.filter(scope=scope)
         if is_active:
             queryset = queryset.filter(is_active=(is_active == 'active'))
+        if combine_mode:
+            queryset = queryset.filter(combine_mode=combine_mode)
         if search:
             queryset = queryset.filter(
                 Q(name__icontains=search) | Q(description__icontains=search)
@@ -92,6 +95,7 @@ class DiscountListView(DiscountAccessMixin, ListView):
             'type': self.request.GET.get('type', ''),
             'scope': self.request.GET.get('scope', ''),
             'is_active': self.request.GET.get('is_active', ''),
+            'combine_mode': self.request.GET.get('combine_mode', ''),
             'search': self.request.GET.get('search', ''),
         }
         context['can_edit'] = self._can_edit()
@@ -110,7 +114,7 @@ class DiscountCreateView(LoginRequiredMixin, RoleRequiredMixin, CreateView):
     template_name = 'discounts/discount_form.html'
     fields = [
         'name', 'description', 'discount_type', 'value', 'scope',
-        'is_auto', 'is_active', 'priority',
+        'is_auto', 'is_active', 'priority', 'combine_mode',
         'start_date', 'end_date',
         'min_order_amount', 'max_usage_count',
         'products', 'categories', 'excluded_products',
@@ -119,6 +123,21 @@ class DiscountCreateView(LoginRequiredMixin, RoleRequiredMixin, CreateView):
     success_url = reverse_lazy('system_settings:discounts:list')
 
     def form_valid(self, form):
+        # Валидация: нельзя создать больше одной активной exclusive скидки на заказ
+        if form.instance.combine_mode == 'exclusive' and form.instance.scope == 'order' and form.instance.is_active:
+            existing_exclusive = Discount.objects.filter(
+                combine_mode='exclusive',
+                scope='order',
+                is_active=True
+            ).exists()
+
+            if existing_exclusive:
+                form.add_error(
+                    'combine_mode',
+                    'Уже существует активная исключающая скидка на заказ. Может быть только одна.'
+                )
+                return self.form_invalid(form)
+
         form.instance.created_by = self.request.user
         messages.success(self.request, f'Скидка "{form.instance.name}" создана')
         return super().form_valid(form)
@@ -142,7 +161,7 @@ class DiscountUpdateView(LoginRequiredMixin, RoleRequiredMixin, UpdateView):
     template_name = 'discounts/discount_form.html'
     fields = [
         'name', 'description', 'discount_type', 'value', 'scope',
-        'is_auto', 'is_active', 'priority',
+        'is_auto', 'is_active', 'priority', 'combine_mode',
         'start_date', 'end_date',
         'min_order_amount', 'max_usage_count',
         'products', 'categories', 'excluded_products',
@@ -151,6 +170,21 @@ class DiscountUpdateView(LoginRequiredMixin, RoleRequiredMixin, UpdateView):
     success_url = reverse_lazy('system_settings:discounts:list')
 
     def form_valid(self, form):
+        # Валидация: нельзя создать больше одной активной exclusive скидки на заказ
+        if form.instance.combine_mode == 'exclusive' and form.instance.scope == 'order' and form.instance.is_active:
+            existing_exclusive = Discount.objects.filter(
+                combine_mode='exclusive',
+                scope='order',
+                is_active=True
+            ).exclude(pk=self.object.pk).exists()
+
+            if existing_exclusive:
+                form.add_error(
+                    'combine_mode',
+                    'Уже существует активная исключающая скидка на заказ. Может быть только одна.'
+                )
+                return self.form_invalid(form)
+
         messages.success(self.request, f'Скидка "{form.instance.name}" обновлена')
         return super().form_valid(form)
 
diff --git a/myproject/orders/admin.py b/myproject/orders/admin.py
index f5f0304..cd06f79 100644
--- a/myproject/orders/admin.py
+++ b/myproject/orders/admin.py
@@ -116,7 +116,6 @@ class OrderAdmin(TenantAdminOnlyMixin, admin.ModelAdmin):
         'status',
         'payment_status',
         'created_at',
-        'applied_discount',
     ]
 
     search_fields = [
@@ -132,7 +131,6 @@ class OrderAdmin(TenantAdminOnlyMixin, admin.ModelAdmin):
         'created_at',
         'updated_at',
         'subtotal_display',
-        'discount_display',
         'amount_due',
         'payment_status',
     ]
@@ -149,16 +147,13 @@ class OrderAdmin(TenantAdminOnlyMixin, admin.ModelAdmin):
         }),
         ('Скидки', {
             'fields': (
-                'applied_discount',
-                'applied_promo_code',
-                'discount_amount',
+                'discount_display',
             ),
             'classes': ('collapse',)
         }),
         ('Оплата', {
             'fields': (
                 'subtotal_display',
-                'discount_display',
                 'total_amount',
                 'amount_paid',
                 'amount_due',
@@ -289,7 +284,6 @@ class OrderItemAdmin(TenantAdminOnlyMixin, admin.ModelAdmin):
     list_filter = [
         'order__status',
         'order__created_at',
-        'applied_discount',
     ]
 
     search_fields = [
@@ -310,10 +304,6 @@ class OrderItemAdmin(TenantAdminOnlyMixin, admin.ModelAdmin):
         ('Информация', {
             'fields': ('quantity', 'price', 'item_discount_display', 'get_total_price')
         }),
-        ('Скидка', {
-            'fields': ('applied_discount', 'discount_amount'),
-            'classes': ('collapse',)
-        }),
         ('Системная информация', {
             'fields': ('created_at',),
             'classes': ('collapse',)
diff --git a/myproject/orders/migrations/0004_remove_old_discount_fields.py b/myproject/orders/migrations/0004_remove_old_discount_fields.py
new file mode 100644
index 0000000..b4233c3
--- /dev/null
+++ b/myproject/orders/migrations/0004_remove_old_discount_fields.py
@@ -0,0 +1,33 @@
+# Generated by Django 5.0.10 on 2026-01-11 10:39
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('orders', '0003_order_applied_discount_order_applied_promo_code_and_more'),
+    ]
+
+    operations = [
+        migrations.RemoveField(
+            model_name='order',
+            name='applied_discount',
+        ),
+        migrations.RemoveField(
+            model_name='order',
+            name='applied_promo_code',
+        ),
+        migrations.RemoveField(
+            model_name='order',
+            name='discount_amount',
+        ),
+        migrations.RemoveField(
+            model_name='orderitem',
+            name='applied_discount',
+        ),
+        migrations.RemoveField(
+            model_name='orderitem',
+            name='discount_amount',
+        ),
+    ]
diff --git a/myproject/orders/models/order.py b/myproject/orders/models/order.py
index 7459ebe..b7786e6 100644
--- a/myproject/orders/models/order.py
+++ b/myproject/orders/models/order.py
@@ -69,29 +69,10 @@ class Order(models.Model):
         help_text="Общая сумма заказа"
     )
 
-    # Скидки
-    applied_discount = models.ForeignKey(
-        'discounts.Discount',
-        on_delete=models.SET_NULL,
-        null=True,
-        blank=True,
-        related_name='orders',
-        verbose_name="Примененная скидка"
-    )
-
-    discount_amount = models.DecimalField(
-        max_digits=10,
-        decimal_places=2,
-        default=0,
-        verbose_name="Сумма скидки"
-    )
-
-    applied_promo_code = models.CharField(
-        max_length=50,
-        blank=True,
-        null=True,
-        verbose_name="Использованный промокод"
-    )
+    # === СКИДКИ ===
+    # Скидки хранятся в модели DiscountApplication (через related_name='discount_applications')
+    # Старые поля applied_discount, discount_amount, applied_promo_code УДАЛЕНЫ
+    # Используйте свойства ниже для доступа к скидкам
 
     # Частичная оплата
     amount_paid = models.DecimalField(
@@ -407,6 +388,7 @@ class Order(models.Model):
         """
         Пересчитывает итоговую сумму заказа.
         total_amount = subtotal + delivery_cost - discount_amount
+        Скидка берётся из DiscountApplication
         """
         from decimal import Decimal
 
@@ -417,7 +399,7 @@ class Order(models.Model):
         if hasattr(self, 'delivery'):
             delivery_cost = self.delivery.cost
 
-        # Вычитаем скидку на весь заказ (если есть)
+        # Вычитаем скидку на весь заказ (из DiscountApplication через свойство)
         order_discount = Decimal(str(self.discount_amount)) if self.discount_amount else Decimal('0')
 
         self.total_amount = subtotal + delivery_cost - order_discount
@@ -432,6 +414,42 @@ class Order(models.Model):
             self.delivery.cost = 0
             self.delivery.save(update_fields=['cost'])
 
+    # === Свойства для доступа к скидкам (через DiscountApplication) ===
+
+    @property
+    def order_discounts(self):
+        """Скидки на заказ (QuerySet DiscountApplication с target='order')"""
+        from discounts.models import DiscountApplication
+        return self.discount_applications.filter(target='order').select_related('discount', 'promo_code')
+
+    @property
+    def item_discounts(self):
+        """Скидки на позиции (QuerySet DiscountApplication с target='order_item')"""
+        from discounts.models import DiscountApplication
+        return self.discount_applications.filter(target='order_item').select_related('discount', 'order_item')
+
+    @property
+    def discount_amount(self):
+        """Общая сумма скидки на заказ"""
+        from decimal import Decimal
+        return self.order_discounts.aggregate(
+            total=models.Sum('discount_amount')
+        )['total'] or Decimal('0')
+
+    @property
+    def applied_discount(self):
+        """Первая применённая скидка (для обратной совместимости)"""
+        first = self.order_discounts.first()
+        return first.discount if first else None
+
+    @property
+    def applied_promo_code(self):
+        """Промокод из первой записи (для обратной совместимости)"""
+        first = self.order_discounts.first()
+        if first and first.promo_code:
+            return first.promo_code.code
+        return None
+
     # === Свойства обратной совместимости для доступа к полям доставки ===
     # Эти свойства обеспечивают доступ к полям Delivery через Order для обратной совместимости
     # после рефакторинга, когда поля доставки были перенесены в отдельную модель Delivery
diff --git a/myproject/orders/models/order_item.py b/myproject/orders/models/order_item.py
index bca0aaf..16938c4 100644
--- a/myproject/orders/models/order_item.py
+++ b/myproject/orders/models/order_item.py
@@ -82,22 +82,10 @@ class OrderItem(models.Model):
         help_text="True если цена была изменена вручную при создании заказа"
     )
 
-    # Скидки
-    applied_discount = models.ForeignKey(
-        'discounts.Discount',
-        on_delete=models.SET_NULL,
-        null=True,
-        blank=True,
-        related_name='order_items',
-        verbose_name="Скидка на позицию"
-    )
-
-    discount_amount = models.DecimalField(
-        max_digits=10,
-        decimal_places=2,
-        default=0,
-        verbose_name="Сумма скидки"
-    )
+    # === СКИДКИ ===
+    # Скидки хранятся в модели DiscountApplication (через related_name='discount_applications')
+    # Старые поля applied_discount, discount_amount УДАЛЕНЫ
+    # Используйте свойства ниже для доступа к скидкам
 
     # Витринные продажи
     is_from_showcase = models.BooleanField(
@@ -254,3 +242,23 @@ class OrderItem(models.Model):
         if self.is_custom_price and self.original_price:
             return self.price - self.original_price
         return None
+
+    # === Свойства для доступа к скидкам (через DiscountApplication) ===
+
+    @property
+    def item_discounts(self):
+        """Скидки на эту позицию (QuerySet DiscountApplication)"""
+        return self.discount_applications.filter(target='order_item').select_related('discount')
+
+    @property
+    def discount_amount(self):
+        """Общая сумма скидки на позицию"""
+        from django.db.models import Sum
+        total = self.item_discounts.aggregate(total=Sum('discount_amount'))['total']
+        return total if total else Decimal('0')
+
+    @property
+    def applied_discount(self):
+        """Первая применённая скидка (для обратной совместимости)"""
+        first = self.item_discounts.first()
+        return first.discount if first else None
diff --git a/myproject/pos/views.py b/myproject/pos/views.py
index 2db3207..05684ee 100644
--- a/myproject/pos/views.py
+++ b/myproject/pos/views.py
@@ -1573,11 +1573,6 @@ def pos_checkout(request):
                     discount_amount = min(discount_value, order.subtotal)
                     discount_name = f'Произвольная скидка {discount_value} руб.'
 
-                order.discount_amount = discount_amount
-                order.applied_promo_code = discount_name  # Сохраняем название в поле промокода
-                order.save(update_fields=['discount_amount', 'applied_promo_code'])
-                order.calculate_total()
-
                 # Создаем запись о применении в истории скидок
                 from discounts.models import DiscountApplication
                 DiscountApplication.objects.create(
@@ -1589,6 +1584,9 @@ def pos_checkout(request):
                     customer=customer,
                     applied_by=request.user
                 )
+
+                # Пересчитываем total_amount (использует DiscountApplication)
+                order.calculate_total()
             elif manual_discount_id:
                 from discounts.services.applier import DiscountApplier
                 from discounts.models import Discount