#!/usr/bin/env ruby

puts 'Rock, paper, scissors Start...'

hands = [:rock, :scissors, :paper]
priority = {
  :rock     => :paper,
  :scissors => :rock,
  :paper    => :scissors
}

loop do
  begin
    puts '=== New Game ==='
    puts 'Please input 1 (Rock) or 2 (Scissors) or 3 (Paper)'

    input = gets.to_i
    raise IOError unless [1, 2, 3].include? input

    player = hands[input - 1]
    cpu    = hands.choice

    res = "#{player} vs #{cpu}  =>  "

    res << case player
           when cpu           : 'Drow'
           when priority[cpu] : 'You Win. Congratulation!'
           else                 'You Lose...'
           end

    puts res
  rescue IOError
    puts 'Input Error. retry...'
    retry
  end
end