dramatis

#!/usr/bin/env ruby

# cf. Scala by Example, Chapter 3

# Note: requires dramatis > 0.1.1

$:.push File.join( File.dirname(__FILE__), "..", "..", "lib" )

require 'dramatis/actor'

require 'dramatis/actor/behavior'

module Auction

  def self.new *args

    Open.new( *args )

  end

  class Open

    include Dramatis::Actor

    def initialize seller, min_bid, closing

      @seller = seller

      @min_bid = min_bid

      @closing = closing

      @bid_increment = 10

      @max_bid = @min_bid - @bid_increment

      @max_bidder = nil

      actor.refuse :winner

      release( actor.name ).close

    end

    def close

      actor.yield @closing - Time::now

      if @max_bid > @min_bid

        release( @seller ).winner @max_bidder

        release( @max_bidder ).winner @seller

        actor.become Over.new( @max_bidder, @max_bid )

      else

        release( @seller ).failed @max_bid

        actor.become Over.new( nil, @max_bid )

      end

    end

    def inquire

      [ @max_bid, @closing ]

    end

    def offer bid, bidder

      if bid >= @max_bid + @bid_increment

        if @max_bid >= @min_bid

          release( @max_bidder ).beaten_offer bid

        end

        @max_bid = bid

        @max_bidder = bidder

        :best_offer

      else

        [ :beaten_offer, @max_bid ]

      end

    end

  end

  class Over

    include Dramatis::Actor::Behavior

    attr_reader :winner, :max_bid

    def initialize winner, max_bid

      @winner = winner

      @max_bid = max_bid

    end

    def dramatis_bound

      actor.accept :winner

    end

    def inquire *args

      [ @max_bid, 0 ]

    end

    def offer *args

      :auction_over

    end

  end

end

class Seller

  include Dramatis::Actor

  def winner winner

  end

  def failed highest_bid

  end

end

class Client

  include Dramatis::Actor

  attr_reader :name

  def initialize name, increment, top, auction

    @name = name

    @increment = increment

    @top = top

    @auction = auction

    @current = 0

    log "started"

    @max = auction.inquire[0]

    log "status #{@max}"

    bid

  end

  def bid

    if @max > @top

      log("too high for me")

    elsif ( @current < @max )

      @current = @max + @increment

      sleep( ( 1 + rand( 1000 ) )/1000.0 )

      answer, max_bid = @auction.offer @current, actor.name

      case answer

      when :best_offer; log("best offer: #{@current}")

      when :beaten_offer; beaten_offer max_bid

      when :auction_over; log("auction over, oh well")

      end

    end

  end

  def beaten_offer max_bid

    log("beaten offer: #{max_bid}")

    @max = max_bid

    release( actor.name ).bid

  end

  def winner seller

    log "I won!"

  end

  def log string

    puts "client #{@name}: #{string}"

  end

end

# somebody gives up

seller = Seller.new

auction = Auction.new seller, 100, Time::now + 4

Client.new "1a", 20, 200, auction

Client.new "2a", 10, 300, auction

puts "Notice: client #{auction.winner.name} won the first auction with a bid of #{auction.max_bid}"

# cut off while people still have money

seller = Seller.new

auction = Auction.new seller, 100, Time::now + 1.5

Client.new "1b", 20, 200, auction

Client.new "2b", 10, 300, auction

puts "Notice: client #{auction.winner.name} won the second auction with a bid of #{auction.max_bid}"

# too expensive

seller = Seller.new

auction = Auction.new seller, 400, Time::now + 1.5

Client.new "1c", 20, 200, auction

Client.new "2c", 10, 300, auction

raise RuntimeError if auction.winner != nil

puts "Notice: the third auction failed; the maximum recieved bid was #{auction.max_bid}"