app.rb

require 'sinatra'
require 'erb'
require 'shellwords'
require 'i18n'
require 'sinatra/i18n'
require_relative 'models/cowsay_validator'
require_relative 'lib/cowsay_characters'

I18n.load_path = Dir[File.join(settings.root, 'locales', '*.yml')]
I18n.config.available_locales = [:en, :pt]
I18n.default_locale = :en

before do
  I18n.locale = request.env['HTTP_ACCEPT_LANGUAGE'].scan(/^[a-z]{2}/).first if request.env['HTTP_ACCEPT_LANGUAGE']
end

get '/' do
  erb :index
end

get '/cowsay_output' do
  cowsay_validator = CowsayValidator.new(
    message: params['message'],
    character: params['character'],
    available_characters: CowsayCharacters.available_characters
  )

  if cowsay_validator.valid?
    escaped_message = Shellwords.escape(cowsay_validator.message)
    escaped_character = Shellwords.escape(cowsay_validator.character)
    @output = `/usr/games/cowsay -f #{escaped_character} #{escaped_message}`
  else
    @output = I18n.t('unavailable_character', character: escaped_character)
  end

  erb :cowsay_output
end

__END__