ExCheckout

A flexible and extensible checkout system designed for a supermarket chain to manage a cart, scan items, and calculate the total price dynamically based on predefined pricing rules.

Features

• Product Scanning:
  • Add products to a cart and calculate the total price dynamically.
• Flexible Pricing Rules:
  • Buy-One-Get-One-Free for Green Tea (GR1).
  • Bulk Discount for Strawberries (SR1): Price drops from £5.00 to £4.50 when buying 3 or more.
  • Volume Discount for Coffee (CF1): Price reduces to two-thirds of the original price when buying 3 or more.
• Scalable architecture:
  • Designed to accommodate new products and pricing rules with minimal changes.

Usage

Prerequisites

• Elixir (1.17 or later)
• Mix (included with Elixir)

Getting Started

1. Clone the repository:

   git clone https://github.com/MuhammadMullah/ex_checkout.git
   cd ex_checkout
   

2. Install Dependancies:

   mix deps.get
   

3. Run Unit Test:

   mix test
   

Example Usage

iex> ExCheckout.scan(["GR1", "SR1", "CF1"])
19.34

Code Readability & Consistency

mix credo --strict

Extensibility

Adding new products or rules:

1. Update the @product_catalog map with the new product and its rule.
2. Implement the rule in the respective function (e.g., calculate_bogo/2, calculate_bulk/3).

Future Improvements

• Dynamic Pricong rules instead of hardcoded ones
• Support for internationalization (e.g., currency formatting).
• Performance optimization. Parallel processing for large input lists by using Task or Flow
• Caching results for frequently scanned products.