Script for easy CZK-USD invoicing

fakturuj.rb

#!/usr/bin/env ruby

require 'net/http'
require 'ostruct'
require 'optparse'

module Fakturuj
  class Application
    # https://github.com/honzajavorek/cs-apis/wiki/Kurzy-devizov%C3%A9ho-trhu-%C4%8CNB
    CNB_DENNI_KURZ_TXT = URI('https://www.cnb.cz/cs/financni_trhy/devizovy_trh/kurzy_devizoveho_trhu/denni_kurz.txt').freeze

    def run(argv)
      @options = parse_cli_options(argv)
      @result = calculate
      $stdout.puts format_result
    end

    attr_reader :options, :result

    private

    def parse_cli_options(argv)
      options = OpenStruct.new
      options.castka = 0.0
      options.minula_castka = 0.0
      options.zaplaceno = 0.0

      opt_parser = OptionParser.new do |opts|
        opts.banner = <<~BANNER
          Pouziti:   fakturuj CASTKA [--minule CASTKA] [--zaplaceno CASTKA] [--datum DD.MM.RRRR]
          Napriklad: fakturuj 21000 --minule 21000 --zaplaceno 18938 --datum 31.3.2020
        BANNER

        opts.separator ''
        opts.separator 'Minula faktura:'
        opts.on('-m', '--minule CASTKA', Float, 'Minule fakturovana castka') do |value|
          options.minula_castka = value
        end
        opts.on('-z', '--zaplaceno CASTKA', Float, 'Zaplacena castka') do |value|
          options.zaplaceno = value
        end

        opts.separator 'Kurz CZK-USD:'
        opts.on('-d', '--datum DATUM', String, 'Datum ve formatu dd.mm.rrrr') do |value|
          options.datum = value
        end
      end

      opt_parser.parse!(argv)
      options.castka = Float(argv[0])
      options.datum ||= Time.now.strftime('%m.%d.%Y')
      options
    end

    def calculate
      OpenStruct.new.tap do |r|
        r.castka = options.castka
        r.minula_castka = options.minula_castka
        r.zaplaceno = options.zaplaceno
        r.datum = options.datum
        r.doplatek = r.minula_castka - r.zaplaceno
        r.platba_czk = r.castka + r.doplatek
        r.kurz_usd = kurz_cnb
        r.platba_usd = r.platba_czk / r.kurz_usd
      end
    end

    def format_result
      <<~TXT % result.to_h
        Aktualni castka:          %<castka>12.02f CZK
        Castka na minule fakture: %<minula_castka>12.02f CZK
        Minule zaplaceno:         %<zaplaceno>12.02f CZK
        Doplatek:                 %<doplatek>12.02f CZK
        ------------------------------------------------------
        K platbe celkem:          %<platba_czk>12.02f CZK
                                  %<platba_usd>12.02f USD
        ------------------------------------------------------
        Kurz CNB USD-CZK k %<datum>s: %<kurz_usd>.3f CZK
      TXT
    end

    def kurz_cnb(country = 'USA')
      uri = CNB_DENNI_KURZ_TXT.dup
      uri.query = "date=#{options.datum}" if options.datum
      body = Net::HTTP.get(uri)
      data = body.split("\n").map { |l| l.split('|') }
      usa_data = data.find { |r| r[0] == country }
      Float(usa_data.last.sub(',', '.'))
    end

  end
end

if File.identical?(__FILE__, $PROGRAM_NAME)
  app = Fakturuj::Application.new
  app.run(ARGV)
end