Covid Vend - The Vending Machine for all your COVID-19 essentials.

This is a command-line vending machine to supply you with all the lockdown essentials you need.

Installation and setup

Ensure you have ruby and sqlite3 installed, then run:

Run bundle install to install any gems.
Run covid-vend init to setup the machine

Usage

bin/covid-vend COMMAND ARGS

Available Commands:

init - This creates a sqlite3 db and fills the machine with stock and change
update_item ITEM_NAME QTY PRICE - This command allows you to add new items to the machine and update the available quantity. Price is in Pennies
purchase_item ITEM_NAME QTY - This command allows you to purchase items. It will ask you to insert an amount of change, then will return your precious stocks to you, for easy depositing in your bunker. If you haven't put in enough money, your change is returned to you. If the machine doesn't have enough money, your change is returned to you
update_change DENOMINATION QTY - This command allows you increment the availabe change in the machine. It expects a string of one of the following denominations 1p,2p,5p,10p,20p,50p,£1,£2 and the quantity to add.
available_items - This lists current stock levels

Architecture

This is built using the commander gem to provide a much faster and more featureful platform to develop CLI applications from.

The main interface to the program is CovidVend. This uses a small number of anciallary objects to perform key tasks such as the Calculator which handles the calculation of change and transactions. The Change object, which provides a light data structure to store change and calculate amounts. Finally, the DBAdapter object provides some conveniece methods for interfacing with the database, using the sequel gem.

Development

Missing something? Really wish the output was ASCII colour formatted? Modify to your heart's content. The core business logic lives in /lib. The main entry point to the vending machine is covid_vend.rb

Tests live in /spec. Run these with bundle exec rspec spec. Currently you need to seed the DB first to run the tests, do this with the init command

Next Steps

Use an in-memory DB for tests
Handle duplicate entries gracefuly
Potential race condition with change if requests made concurrently, move to transaction

christopherdbull / covid-vending