Setup

The Dockerfile expects your local user to have uid 1000 and gid 1000. If they are different update the Dockerfile accordingly.

Initial setup:

mkdir -p tmp/bundle
docker-compose up
docker-compose exec web bundle --jobs=8
docker-compose exec web rails db:setup

Then, for developing:

docker-compose up
docker-compose exec web rails s -b 0.0.0.0
docker-compose exec web rails c

The website can be opened at http://localhost:3000. The docker-compose.yml is mounting your host folder in the container. So changes you make on the app will automatically be reflected in the container.

Your tasks

1. As a user I want to upload an excel file of barcodes in order to let the system know which barcodes have already been printed from another system

Implement new view/ form with one file input field and submit button (barcodes#import)
The uploaded excel contains the barcodes in the first column, one barcode per row. Skip the first row.
In case upload is missing or is not an excel file, highlight input and redirect to upload page
In case of any invalid barcodes (invalid ean8 or duplicate)
- don't store anything in the database
- display the error "Invalid barcodes found: xxx, xxx, xxx, ..." (ex: "Invalid barcodes found: 4545455, 0235433.")
In case of only valid barcodes
- redirect to root page
- display notice "xxx barcodes imported!" (ex: "5 barcodes imported!")
The barcodes should have source "excel" in the database

2. As a user I want to upload the raw excel we get from our partner in order to have less manual work for preparation

Enhance existing barcode upload from task one
If the barcode has more than 8 digits it's invalid
If the barcode has less than 8 digits
- left pad with zeros to 8 digits and check if the barcode is a valid EAN8
  - if it's not a valid EAN8
    - left pad to only to 7 digits,
    - calculate the checksum and append it to the right

3. As a user I want to generate a certain amount of barcodes manually in order to give the programmer some work

Add button "Generate new barcodes"
Clicking on the button
- generates a random number (1 - 100) of new barcodes
- displays a notice "xxx barcodes generated"
- redirects to root
The generation should start with the lowest possible number and respect any existing barcodes in the database
- example, dbs contains: 00000017, 000000024, 00000055
- after generating 3 new barcodes, dbs contains: 00000017, 000000024, 00000031 (new), 00000048 (new), 00000055, 00000062 (new)
The barcodes should have source "generator" in the database

Hints / rules

Use can use the excel files in the doc folder for testing
Use gems already present in Gemfile (ean8, rubyXL)
See doc/code_snippets.rb for some hints (no need to use it)
Use form and service objects where it makes sense
Code should be clean, well structured and self-documentating (proper method naming, etc.)
Write down in keywords what problems/ difficulties you faced
Write down in keywords what could be improved/ refactored in your code
Bonus points for: write some unit and controller specs for your tasks