Constructor

OnlineShoppingApplication(List<String> productDetails)

• productDetails contains the complete product catalogue.
• Each string describes one product using "productId,productName,category,priceInCents".
• Product names and categories never contain commas.
• Product IDs are unique, and prices are non-negative integers.

Invalid Product Rows

• It does not contain exactly four comma-separated values.
• Its product ID, product name, or category is empty.
• Its price is not a valid non-negative integer.
• Its product ID was already used by an earlier valid row. Keep the first valid product and ignore later duplicates.

Method Signatures

Search Products

List<String> searchProducts(String keyword)

• Return products whose names or categories contain keyword.
• Matching is case-insensitive.
• Return each product using "productId,productName,category,priceInCents".
• Return matches in their original constructor order.
• An empty keyword matches every valid product.
• Return an empty list when no product matches.

Add Product to Cart

List<String> addToCart(String customerId, String productId, int quantity)

• Add the specified product and quantity to the customer's active cart.
• Create a cart automatically when the customer adds their first product.
• If the product is already in the cart, increase its existing quantity.
• Return the complete updated cart.

• "ERROR,EMPTY_CUSTOMER_ID"
• "ERROR,PRODUCT_NOT_FOUND"
• "ERROR,INVALID_QUANTITY"

Place Order

List<String> placeOrder(String customerId, String orderId)

• Create an order from all products currently present in the customer's cart.
• The supplied orderId must be used for the order.
• Order IDs must be unique across all customers.
• Copy each product's name, price, and quantity into the order.
• Set the payment status to PENDING.
• Set the order status to PENDING_PAYMENT.
• Clear the cart only after the order is successfully created.

• "ERROR,EMPTY_CUSTOMER_ID"
• "ERROR,EMPTY_ORDER_ID"
• "ERROR,DUPLICATE_ORDER_ID"
• "ERROR,EMPTY_CART"

Update Payment Status

List<String> updatePaymentStatus(String orderId, String paymentStatus)

• paymentStatus must be PENDING, SUCCESSFUL, or FAILED.
• Set the order status to PENDING_PAYMENT for PENDING.
• Set the order status to CONFIRMED for SUCCESSFUL.
• Set the order status to PAYMENT_FAILED for FAILED.
• A failed payment may subsequently be updated to SUCCESSFUL.
• Once payment becomes SUCCESSFUL, it cannot be changed again.
• Return the complete updated order in the order format defined above.

• "ERROR,ORDER_NOT_FOUND"
• "ERROR,UNSUPPORTED_PAYMENT_STATUS"
• "ERROR,PAYMENT_ALREADY_SUCCESSFUL"

Fetch Recent Orders

List<String> getRecentOrders(String customerId)

• Return at most the 10 most recently placed orders of the customer.
• If the customer has fewer than 10 orders, return all their orders.
• Return the most recent order first.
• Represent each order using "ORDER,orderId,customerId,totalInCents,paymentStatus,orderStatus".
• The returned summaries must reflect the latest payment and order statuses.
• Return an empty list if customerId is empty, the customer does not exist, or the customer has not placed any orders.

Constraints

• 1 ≤ productDetails.size() ≤ 10,000
• Every valid product row contains exactly four comma-separated values.
• 1 ≤ productId.length(), productName.length(), category.length() ≤ 100
• customerId, orderId, Product names and categories never contain commas.
• Valid product IDs are unique and never contain commas.
• 0 ≤ priceInCents ≤ 1,000,000,000
• 0 ≤ keyword.length() ≤ 100
• 0 ≤ customerId.length(), orderId.length() ≤ 100
• 1 ≤ quantity ≤ 1,000,000 for valid quantities.
• Every cart and order total fits in a signed 64-bit integer.
• All information is stored in memory.
• No parameter passed to the constructor or any method will be null.
• The constructor and methods must never throw exceptions.

Examples

Example 1: Invalid Products, Search, and Cart

Example 2: Orders and Payment Status

Example 3: Fetching Recent Orders