gistfile1.rb

class PlingPlangPlong
  def initialize(number)
    @number = number
  end

  def call
    has_terms? ? joined_terms : number.to_s
  end

  private

  attr_reader :number

  def has_terms?
    prime_factors.empty?
  end

  def joined_terms
    prime_factors.reduce([]) { |accum, factor| accum << term_for(factor) }.join
  end

  def term_for(factor)
    terms.fetch(factor)
  end

  def prime_factors
    terms.keys.select {|x| number % x == 0}
  end

  def terms
    {
      3 => "Pling",
      5 => "Plang",
      7 => "Plong",
    }
  end
end