#!/usr/bin/env ruby -w

require "yaml"
require "drb"

$SAFE = 1
PORT  = 61676

class DRbChallenger
  def self.host(challenges = nil)
    hosted_challenges = challenges || new
    DRb.start_service("druby://0.0.0.0:#{PORT}", hosted_challenges)
    puts "Now serving challenges on port #{PORT}..."
    hosted_challenges
  end
  
  def self.join(ip_address)
    DRb.start_service
    puts "Connecting to challenges on port #{PORT} at IP #{ip_address}..."
    challenges = DRbObject.new_with_uri("druby://#{ip_address}:#{PORT}")
    $stdout.extend(DRbUndumped)
    challenges.drb_stdout = $stdout
    challenges
  end
  
  def self.load(file_name = "regexp_challenge.yaml")
    File.open(file_name) { |file| YAML.load(file) }
  end
  
  def initialize
    @challenges = Array.new
    @solutions  = Array.new
    
    @drb_stdout = nil
  end
  
  attr_writer :drb_stdout
  
  def io
    if caller.any? { |call| call =~ /\bdrb\b/ }
      @drb_stdout || $stdout
    else
      $stdout
    end
  end
  
  def challenge(input, output, note = nil)
    @challenges << [input, output, note] and nil
  end
  
  def challenges
    @challenges.each_with_index do |challenge, i|
      io.puts describe_challenge(challenge, i)
    end && nil
  end
  alias_method :inspect, :challenges
  
  def solve(challenge_number)
    
    answer = yield(@challenges[challenge_number][0])    
      #@challenges[challenge_number][0].send( method_call,*args )
    if answer == @challenges[challenge_number][1]
      io.puts "Correct.  Nice job."
      @solutions << @challenges.slice!(challenge_number) 
    else
      io.puts "That is not a valid solution."
      io.puts "Expected output:  #{@challenges[challenge_number][1].inspect}"
      io.puts "    Your output:  #{answer.inspect}"
    end && nil
  end
  
  def solutions
    @solutions.each_with_index do |solution, i|
      io.puts describe_challenge(solution, i, "Solution").
              map { |line| line.sub(/^  /, "\\0\\0") }
      description = "  Solution:  #{solution[3]}(#{solution[4].inspect}"
      io.puts description + ")"
    end && nil
  end
  
  def save(file_name = "regexp_challenge.yaml")
    File.open(file_name, "w") { |file| YAML.dump(self, file) }
  end
  
  private
  
  def describe_challenge(challenge, number, title = "Challenge")
    description = [ "#{title} ##{number}:",
                    "   Input:  #{challenge[0].inspect}",
                    "  Output:  #{challenge[1].inspect}", ]
    unless challenge[2].nil?
      description << "    Note:  #{challenge[2].inspect}"
    end
    description
  end
end