require 'drb/drb'
require 'rinda/rinda'
require 'monitor'

class RemoteNQueen
  class Stream
    include MonitorMixin
    def initialize(block)
      super()
      @block = block
    end

    def push(x)
      synchronize do
        @block.call(x)
      end
    end
  end

  def initialize(tuplespace)
    super()
    @ts = tuplespace
  end

  def expand(size, &block)
    key = "#{DRb.uri}:#{id}"
    stream = Stream.new(block)

    size.times do |row|
      @ts.write([:nqueen, key, size, [], row, DRbObject.new(stream)])
    end
    size.times do |row|
      @ts.take([:nqueen_done, key])
    end
  end
end

if __FILE__ == $0
  DRb.start_service

  ts_uri = ARGV.shift || raise
  ts = DRbObject.new(nil, ts_uri)

  rq = RemoteNQueen.new(ts)
  rq.expand((ARGV.shift || '5').to_i) do |x|
    puts x.join(" ")
  end
end