Companies-filter

Description

It's a test task for Subneon.co.

For task description see here: TASK_DESCRIPTION.md

How use

In .src/main/resources/ replace existed companies.csv and filters.json with your real data.

Execute

sbt run

Result will be saved to top3_companies.csv in project directory

How work:

• read and parse filters from json file
• read and parse companies from csv file
• filter companies
• fold to top 3 companies by revenue
• save result to csv file

Stack

• scala, sbt
• cats-effects
• fs2
• fs2-data
• circe
• scalatest

TODO

1. More unit-tests

2. Better abstraction for fold on stream for create any samples:

   • TopByRevenue(size)
   • WorstByRevenue(size)
   • etc.

3. Use arguments for config paths to data, filters and result

Remarks

1. Json format for filters inconvenient for parsing with auto-derive codecs:

   { "filterType": "NameContains", "text": "foo" }

   better if we move specific filter fields to optional object:

   { "filterType": "NameContains", "options": { "text": "foo"} }

   in this variant we can create filter with polymorph options:

   case class Filter[T](filterType: String, options: T)

   case class ByNameFilterOption(text: String)

   and after with Circe (or other json-lib) easy derive codecs for our filters without using json cursors or other custom logic.

2. We can separate filter name and filter logic for better abstraction and composite logic:

   { "filterType": "NameContains", "text": "foo" } { "filterType": "IsProfitable" }

   with additional field:

   { "name": "NameContains", "type": "ByField", "condition": "Contains", "options": { "value": "foo" } } { "name": "IsProfitable", "type": "ByField", "condition": "Equals", "options": { "value": true } }