5830 add basic discount models and apis (#164)

* Create discount model

* Add discount models and methods

* Add API endpoint

* Add some more helper methods

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* more updates

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* Add discount form to cart template

* remove console log

* Can add discount to basket

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* fix clear button

* Remove unused discounts from basket

* format

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* Clean up migrations

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* Add some enhancements to UI, fix migration

* ruff

* Try fixing openapi

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* fix

* fix

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* generate open API

* Fix tests

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* fix more tests

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* Fix tests

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* Add api tests

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* tests

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* Add negative tests

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* lint

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* prevent default

* Fix exception

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

cart/templates/cart.html

@@ -21,6 +21,7 @@
                     <th scope="col">Product</th>
                     <th scope="col">Price</th>
                     <th scope="col">Quantity</th>
+                    <th scope="col">Discount code</th>
                     <th scope="col">Total</th>
                 </tr>
             </thead>
@@ -35,7 +36,8 @@
                     <td>{{ item.product }}</td>
                     <td>{{ item.product.price }}</td>
                     <td>{{ item.quantity }}</td>
-                    <td>{{ item.product.price }}</td>
+                    <td>{{ item.best_discount_for_item_from_basket.discount_code }}</td>
+                    <td>{{ item.price }}</td>
                 </tr>
                 {% endfor %}
             </tbody>
@@ -73,6 +75,31 @@
             </div>
         </form>
     </div>
+    <div class="col-12">
+        <p>Add a discount code to the basket:</p>
+
+        <form method="post" id="discountform">
+            {% csrf_token %}
+            <input name="discount_code" id="discount_code"/>
+            <div class="form-group d-flex align-items-end mt-2">
+                <button type="submit" class="wl-auto btn btn-primary me-2">Add discount</button>
+            </div>
+        </form>
+        <table class="table">
+            <thead>
+                <tr>
+                    <th scope="col">Discount codes</th>
+                </tr>
+            </thead>
+            <tbody>
+                {% for discount in basket.discounts.all %}
+                <tr>
+                    <td>{{ discount }}</td>
+                </tr>
+                {% endfor %}
+            </tbody>
+        </table>
+    </div>
 </div>
 
 <script type="text/javascript">
@@ -100,12 +127,28 @@
     return false;
 }
 
+function add_discount(event) {
+    event.preventDefault();
+    var discount_code = encodeURIComponent(document.getElementById("discount_code").value);
+    var csrfmiddlewaretoken = encodeURIComponent(document.querySelector("input[name='csrfmiddlewaretoken']").value);
+    var system_slug = "{{ basket.integrated_system.slug }}";
+    axios.post(`/api/v0/payments/baskets/add_discount/${system_slug}/`, {discount_code: discount_code}, { headers: { "X-CSRFToken": csrfmiddlewaretoken }})
+        .then(function (response) {
+            window.location.reload();
+        })
+     .catch(function (error) {
+            alert(error);
+        });
+
+    return false;
+}
+
 function clear_cart(event) {
     event.preventDefault();
 
     var csrfmiddlewaretoken = encodeURIComponent(document.querySelector("input[name='csrfmiddlewaretoken']").value);
-
-    axios.delete(`/api/v0/payments/baskets/clear/`, { headers: { "X-CSRFToken": csrfmiddlewaretoken } })
+    var system_slug = "{{ basket.integrated_system.slug }}";
+    axios.delete(`/api/v0/payments/baskets/clear/${system_slug}/`, { headers: { "X-CSRFToken": csrfmiddlewaretoken } })
         .then(function (response) {
             window.location.reload();
         })
@@ -117,6 +160,7 @@
 }
 
 document.getElementById("cartform").addEventListener("submit", add_to_cart);
+document.getElementById("discountform").addEventListener("submit", add_discount);
 document.getElementById("clear-button").addEventListener("click", clear_cart);
 </script>
 {% endblock body %}

openapi/specs/v0.yaml

@@ -349,6 +349,26 @@ paths:
               schema:
                 $ref: '#/components/schemas/BasketWithProduct'
           description: ''
+  /api/v0/payments/baskets/add_discount/{system_slug}/:
+    post:
+      operationId: payments_baskets_add_discount_create
+      description: Creates or updates a basket for the current user, adding the discount
+        if valid.
+      parameters:
+      - in: path
+        name: system_slug
+        schema:
+          type: string
+        required: true
+      tags:
+      - payments
+      responses:
+        '200':
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/BasketWithProduct'
+          description: ''
   /api/v0/payments/baskets/clear/{system_slug}/:
     delete:
       operationId: payments_baskets_clear_destroy
@@ -449,9 +469,25 @@ components:
         id:
           type: integer
           readOnly: true
+        price:
+          type: number
+          format: double
+          description: Return the total price of the basket item with discounts.
+          readOnly: true
+        discounted_price:
+          type: number
+          format: double
+          description: |-
+            Get the price of the basket item with applicable discounts.
+
+            Returns:
+                Decimal: The price of the basket item reduced by an applicable discount.
+          readOnly: true
       required:
       - basket
+      - discounted_price
       - id
+      - price
       - product
     BasketWithProduct:
       type: object
@@ -561,8 +597,13 @@ components:
           type: integer
         integrated_system:
           type: integer
+        discounts:
+          type: array
+          items:
+            type: integer
       required:
       - created_on
+      - discounts
       - id
       - integrated_system
       - updated_on

payments/admin.py

@@ -140,3 +140,31 @@ class RefundedOrderAdmin(BaseOrderAdmin):
     def get_queryset(self, request):
         """Filter only to refunded orders"""
         return super().get_queryset(request).filter(state=models.Order.STATE.REFUNDED)
+
+
+@admin.register(models.Discount)
+class DiscountAdmin(admin.ModelAdmin):
+    model = models.Discount
+    search_fields = ["discount_type", "redemption_type", "discount_code"]
+    list_display = [
+        "id",
+        "discount_code",
+        "discount_type",
+        "amount",
+        "redemption_type",
+        "payment_type",
+    ]
+    list_filter = ["discount_type", "redemption_type", "payment_type"]
+
+
+@admin.register(models.RedeemedDiscount)
+class RedeemedDiscountAdmin(admin.ModelAdmin):
+    model = models.RedeemedDiscount
+    search_fields = ["discount", "order", "user"]
+    list_display = [
+        "id",
+        "discount",
+        "order",
+        "user",
+    ]
+    list_filter = ["discount", "order", "user"]

payments/api.py

@@ -5,6 +5,7 @@
 from django.conf import settings
 from django.core.exceptions import ObjectDoesNotExist, PermissionDenied, ValidationError
 from django.db import transaction
+from django.db.models import Q, QuerySet
 from django.urls import reverse
 from ipware import get_client_ip
 from mitol.payment_gateway.api import CartItem as GatewayCartItem
@@ -14,6 +15,7 @@
 from payments.exceptions import PaymentGatewayError, PaypalRefundError
 from payments.models import (
     Basket,
+    Discount,
     FulfilledOrder,
     Order,
     PendingOrder,
@@ -436,3 +438,27 @@ def process_post_sale_webhooks(order_id, source):
             continue
 
         send_post_sale_webhook.delay(system.id, order.id, source)
+
+
+def get_auto_apply_discounts_for_basket(basket_id: int) -> QuerySet[Discount]:
+    """
+    Get the auto-apply discounts that can be applied to a basket.
+
+    Args:
+        basket_id (int): The ID of the basket to get the auto-apply discounts for.
+
+    Returns:
+        QuerySet: The auto-apply discounts that can be applied to the basket.
+    """
+    basket = Basket.objects.get(pk=basket_id)
+    return (
+        Discount.objects.filter(
+            Q(product__in=basket.get_products()) | Q(product__isnull=True)
+        )
+        .filter(
+            Q(integrated_system=basket.integrated_system)
+            | Q(integrated_system__isnull=True)
+        )
+        .filter(Q(assigned_users=basket.user) | Q(assigned_users__isnull=True))
+        .filter(automatic=True)
+    )