Added basic cart abstraction layer

artel/artel/settings/base.py

@@ -173,3 +173,6 @@ WAGTAILADMIN_BASE_URL = "http://example.com"
 
 # STORE SETTINGS
 PRODUCTS_PER_PAGE = 6
+
+# CART settings
+CART_SESSION_ID = 'cart'

artel/store/cart.py

@@ -0,0 +1,78 @@
+from abc import (
+    ABC,
+    abstractmethod
+)
+from typing import List
+from dataclasses import dataclass
+from django.http.request import HttpRequest
+from django.conf import settings
+
+from store.models import Product
+
+
+@dataclass
+class CartItem:
+    product: Product
+    quantity: int
+
+
+class BaseCart(ABC):
+
+    def validate_item_id(self, item_id):
+        return Product.objects.get(id=item_id)
+
+    @abstractmethod
+    def add_item(self, item_id, quantity):
+        ...
+    
+    @abstractmethod
+    def remove_item(self, item_id):
+        ...
+
+    @abstractmethod
+    def update_item_quantity(self, item_id, change):
+        ...
+    
+    @abstractmethod
+    def get_items(self):
+        ...
+
+
+class SessionCart(BaseCart):
+
+    def __init__(self, request: HttpRequest) -> None:
+        super().__init__()
+        self.session = request.session
+        if not self.session.get(settings.CART_SESSION_ID):
+            self.session[settings.CART_SESSION_ID] = {}
+
+    def add_item(self, item_id, quantity):
+        # TODO - add logging
+        self.validate_item_id(item_id)
+
+        if not self.session[settings.CART_SESSION_ID].get(item_id):
+            self.session[settings.CART_SESSION_ID][item_id] = quantity
+        else:
+            self.update_item_quantity(item_id, quantity)
+
+    def remove_item(self, item_id):
+        self.validate_item_id(item_id)
+        try:
+            self.session[settings.CART_SESSION_ID].pop(item_id)
+        except KeyError:
+            # TODO - add logging
+            ...
+    
+    def update_item_quantity(self, item_id, change):
+        self.validate_item_id(item_id)
+        try:
+            self.session[settings.CART_SESSION_ID][item_id] += change
+        except KeyError:
+            # TODO - add logging
+            self.add_item(item_id, change)
+
+    def get_items(self) -> List[CartItem]:
+        _items = []
+        for item_id, quantity in self.session[settings.CART_SESSION_ID].items():
+            _items.append(CartItem(quantity=quantity, product=Product.objects.get(id=item_id)))
+        return _items

artel/store/static/js/cart.js

@@ -0,0 +1,34 @@
+// Add item to cart on form submission
+$('#add-to-cart-form').on('submit', function(event) {
+    event.preventDefault();
+    const form = $(this);
+    const formData = new FormData(form[0]); // Serialize the form data correctly
+    $.ajax({
+        type: form.attr('method'),
+        url: form.attr('action'),
+        data: formData, // Use the serialized form data
+        dataType: 'json',
+        processData: false, // Prevent jQuery from processing the data
+        contentType: false, // Let the browser set the content type
+        success: function(data) {
+            alert(data.message);
+            fetchCartItems();
+        }
+    });
+});
+
+// Fetch cart items and update the display
+function fetchCartItems() {
+    fetch('/cart/')
+        .then(response => response.json())
+        .then(data => {
+            const cartItems = data.cart_items;
+            const cartItemsList = $('#cart-items');
+            cartItemsList.empty();
+            cartItems.forEach(item => {
+                const li = $('<li>').text(`Product ID: ${item.product_id}, Quantity: ${item.quantity}`);
+                cartItemsList.append(li);
+                
+            });
+        });
+}