#!/usr/bin/env ruby

class Dice
 attr_accessor :a

  def initialize
    @a = ARGV.first
  end

  def welcome
    puts "Simple dice roll emulator"
    puts "--------------------------"

    if @a == nil
      puts "Type '--help' for commands list"
    elsif @a == "--help"
      puts "to roll a certain dice type in:"
      puts "d4, d6, d8, d10, d12, d16, d18, d20"
      puts "to quit the program type in 'q'"
      puts "..................................."
    end
  end

  def roll
    @d4 = (1..4).to_a
    @d6 = (1..6).to_a
    @d8 = (1..8).to_a
    @d10 = (1..10).to_a
    @d12 = (1..12).to_a
    @d16 = (1..16).to_a
    @d18 = (1..18).to_a
    @d20 = (1..20).to_a
  end

  def roll_desc
    puts "The roll is '#{@dice}'"
    puts "\n"
  end

  def emulator
    welcome
    roll
    loop do
      puts "Pick a dice to roll:"
      @d = STDIN.gets.chomp
      @d = @d.downcase
      if @d.match(/[d](4|6|8|10|12|14|16|18|20)|q/i)
        if @d == 'd4'
          @dice = @d4.sample
          roll_desc
        elsif @d == 'd6'
          @dice = @d6.sample
          roll_desc
        elsif @d == 'd8'
          @dice = @d8.sample
          roll_desc
        elsif @d == 'd10'
          @dice = @d10.sample
          roll_desc
        elsif @d == 'd12'
          @dice = @d12.sample
          roll_desc
        elsif @d == 'd16'
          @dice = @d16.sample
          roll_desc
        elsif @d == 'd18'
          @dice = @d18.sample
          roll_desc
        elsif @d == 'd20'
          @dice = @d20.sample
          roll_desc
        elsif @d == 'q'
          exit
        end
      else
        puts "Wrong input, try again, or see 'dice.rb --help' for reference"
        puts "\n"
      end
    end
  end
end

if __FILE__ == $0
  d = Dice.new
  d.emulator
end