Secret Santa Exercise

secret_santa.rb

class SecretSanta
  attr_accessor :people

  def initialize(file)
    @people = []
    File.new(file).each_line do |line|
      first, last = line.split(' ')
      @people << Person.new(first, last)
    end
    assign_santas
  end

  def assign_santas
    print '.'
    @people.shuffle.each_with_index do |person, i|
      @people[i].ss_for = person
    end
  end

  def valid?
    @people.all? do |person|
      person.last_name != person.ss_for.last_name
    end
  end
end

class Person
  attr_accessor :first_name, :last_name, :ss_for
  def initialize(first, last)
    @first_name = first
    @last_name = last
  end

  def to_s
    "#{first_name} #{last_name}"
  end
end

if __FILE__ == $0
  santas = SecretSanta.new('people.txt')
  santas.assign_santas until santas.valid?
  puts
  santas.people.each do |person|
    printf "%20s is a secret santa for %-20s\n", person.ss_for, person
  end
end