Grocery Store Till System - Developer Exercise

This exercise is designed to demonstrate a candidate's abilities across a range of competencies in software development. You may use any programming language and frameworks of your choice.

Instructions

1. Fork the repository
2. Implement a solution that meets the requirements below
3. Share your forked repository with us

Feel free to use any helper packages/frameworks that you think will be beneficial.

Business Requirements

Overview

Create a grocery store till system that can scan items and calculate the total bill with support for promotional discounts. The currency is aws with 100 clouds (c) = 1 aws.

Core Functionality

1. Product Management

The till must support configuration of products with:

• Name (unique identifier)
• Price in clouds
• Category (e.g., "fruit", "vegetable", "bakery")

2. Promotional Rules

Implement the following discount types:

Bundle Discount (X for Y)

• Customer buys X items from a specified list but only pays for Y of them
• The cheapest item(s) are free
• If more items than X are scanned, only the first X items found are eligible for the discount
• Multiple separate bundles can be applied if enough items exist

Progressive Discount (Buy X Get Next at Y% off)

• When buying multiple of the same item, receive progressive discounts
• Can be configured for any percentage off and any quantity threshold
• Example: "Buy 1 Get 1 at 50% off" or "Buy 2 Get 1 at 25% off"

Bulk Purchase (X or more for Y clouds each)

• When buying X or more of the same item, each item costs Y clouds instead of the regular price
• Example: "3 or more apples for 40c each" (regular price might be 50c)

3. Discount Priority and Conflicts

When an item qualifies for multiple discounts:

• Each item can only be part of ONE discount
• The system should apply the discount that gives the customer the best value
• Document your logic for handling these scenarios

Example Scenario

Product Catalog: Product Price Category apple 50c fruit banana 40c fruit tomato 30c vegetable potato 26c vegetable bread 120c bakery milk 95c dairy

Active Promotions:

1. Bundle Discount: 3 for 2 on ["apple", "banana", "tomato"]
2. Progressive Discount: Buy 1 Get 1 at 50% off on "potato"
3. Bulk Purchase: 4 or more "bread" for 100c each

Scanned Basket:

["apple", "banana", "banana", "potato", "tomato", "banana", "potato"]

Expected Calculation:

1. Bundle Discount (3 for 2): "apple", "banana", "banana" → Pay for apple (50c) + banana (40c) = 90c (one 40c banana is free)
2. Progressive Discount: "potato", "potato" → 26c + 13c = 39c (second potato is 50% off)
3. Regular Price: "tomato" (30c) + "banana" (40c) = 70c
4. Total: 90c + 39c + 70c = 199c = 1 aws and 99 clouds

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Technical Requirements

Your solution should demonstrate:

1. Till Operations

• Scan items one at a time or in batch
• Calculate running total
• Apply promotional discounts automatically
• Display itemized receipt showing:
  • Each scanned item and its price
  • Applied discounts with savings amount
  • Final total in aws and clouds

2. Configuration Interface

Administrators should be able to:

• Add/remove/update products
• Create/modify/remove promotional rules
• View current product catalog and active promotions

3. Edge Cases to Consider

• Scanning items not in the catalog
• Empty baskets
• Scanning the same item multiple times
• Multiple overlapping promotions
• Items that could qualify for multiple discount types

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Delivery Format

Choose one of the following formats for your solution:

1. REST API - With endpoints for configuration and checkout operations
2. CLI Application - Interactive command-line interface
3. Web Application - UI for both customer and administrator views

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Questions?

Feel free to make reasonable assumptions where requirements are ambiguous, but document them in your README. Good luck! 🛒