first commit

services/cart/service.go

@@ -0,0 +1,96 @@
+package cart
+
+import (
+	"fmt"
+
+	"sismedika.com/sas/westone/types"
+)
+
+func getCartItemsIDs(items []types.CartCheckoutItem) ([]int, error) {
+	productIds := make([]int, len(items))
+	for i, item := range items {
+		if item.Quantity <= 0 {
+			return nil, fmt.Errorf("invalid quantity for product %d", item.ProductID)
+		}
+
+		productIds[i] = item.ProductID
+	}
+
+	return productIds, nil
+}
+
+func checkIfCartIsInStock(cartItems []types.CartCheckoutItem, products map[int]types.Product) error {
+	if len(cartItems) == 0 {
+		return fmt.Errorf("cart is empty")
+	}
+
+	for _, item := range cartItems {
+		product, ok := products[item.ProductID]
+		if !ok {
+			return fmt.Errorf("product %d is not available in the store, please refresh your cart", item.ProductID)
+		}
+
+		if product.Quantity < item.Quantity {
+			return fmt.Errorf("product %s is not available in the quantity requested", product.Name)
+		}
+	}
+
+	return nil
+}
+
+func calculateTotalPrice(cartItems []types.CartCheckoutItem, products map[int]types.Product) float64 {
+	var total float64
+
+	for _, item := range cartItems {
+		product := products[item.ProductID]
+		total += product.Price * float64(item.Quantity)
+	}
+
+	return total
+}
+
+func (h *Handler) createOrder(products []types.Product, cartItems []types.CartCheckoutItem, userID int) (int, float64, error) {
+	// create a map of products for easier access
+	productsMap := make(map[int]types.Product)
+	for _, product := range products {
+		productsMap[product.ID] = product
+	}
+
+	// check if all products are available
+	if err := checkIfCartIsInStock(cartItems, productsMap); err != nil {
+		return 0, 0, err
+	}
+
+	// calculate total price
+	totalPrice := calculateTotalPrice(cartItems, productsMap)
+
+	// reduce the quantity of products in the store
+	for _, item := range cartItems {
+		product := productsMap[item.ProductID]
+		product.Quantity -= item.Quantity
+		h.store.UpdateProduct(product)
+	}
+
+	// create order record
+	orderID, err := h.orderStore.CreateOrder(types.Order{
+		UserID:  userID,
+		Total:   totalPrice,
+		Status:  "pending",
+		Address: "some address", // could fetch address from a user addresses table
+	})
+	if err != nil {
+		return 0, 0, err
+	}
+
+	// create order the items records
+	for _, item := range cartItems {
+		h.orderStore.CreateOrderItem(types.OrderItem{
+			OrderID:   orderID,
+			ProductID: item.ProductID,
+			Quantity:  item.Quantity,
+			Price:     productsMap[item.ProductID].Price,
+		})
+	}
+
+	return orderID, totalPrice, nil
+}