# Originally was implemented by Yaroslav Markin in "russian" gem
# (http://github.com/yaroslav/russian)
#
# Used for Belarusian, Russian, Ukrainian.

module RailsI18n
  module Pluralization
    module EastSlavic
      FROM_2_TO_4   = (2..4).to_a.freeze
      FROM_5_TO_9   = (5..9).to_a.freeze
      FROM_11_TO_14 = (11..14).to_a.freeze
      FROM_12_TO_14 = (12..14).to_a.freeze

      def self.rule
        lambda do |n|
          return :other unless n.is_a?(Numeric)

          mod10 = n % 10
          mod100 = n % 100

          if mod10 == 1 && mod100 != 11
            :one
          elsif FROM_2_TO_4.include?(mod10) && !FROM_12_TO_14.include?(mod100)
            :few
          elsif mod10 == 0 || FROM_5_TO_9.include?(mod10) || FROM_11_TO_14.include?(mod100)
            :many
          else
            :other
          end
        end
      end

      def self.with_locale(locale)
        { locale => {
            :i18n => {
              :plural => {
                :keys => [:one, :few, :many, :other],
                :rule => rule }}}}
      end
    end
  end
end