Starbuzz Coffee Ordering Systems

starbuzz_ordering_systems.rb

class Beverage
  attr_reader :description

  def initialize()
    @description = "Unknown beverage"
  end

  def cost()
    raise NotImplementedError
  end
end

class Espresso < Beverage
  def initialize()
    @description = "Espresso"
  end

  def cost()
    1.99
  end
end

class HouseBlend < Beverage
  def initialize()
    @description = "House blend coffee"
  end

  def cost()
    0.89
  end
end

class DarkRoast < Beverage
  def initialize()
    @description = "Dark roast coffee"
  end

  def cost()
    0.99
  end
end

###

class CondimentDecorator < Beverage
  def description
    raise NotImplementedError
  end
end

class Mocha < CondimentDecorator
  attr_reader :beverage

  def initialize(beverage)
    @beverage = beverage
  end

  def description
    beverage.description + ", mocha"
  end

  def cost()
    beverage.cost() + 0.20
  end
end

class Soy < CondimentDecorator
  attr_reader :beverage

  def initialize(beverage)
    @beverage = beverage
  end

  def description
    beverage.description + ", soy"
  end

  def cost()
    beverage.cost() + 0.15
  end
end

class Whip < CondimentDecorator
  attr_reader :beverage

  def initialize(beverage)
    @beverage = beverage
  end

  def description
    beverage.description + ", whip"
  end

  def cost()
    beverage.cost() + 0.10
  end
end

###

class StarbuzzCoffee
  def self.start()
    prices = []

    beverage1 = Espresso.new
    prices << "%-60s $%5.2f" % [ beverage1.description, beverage1.cost() ]

    beverage2 = DarkRoast.new
    beverage2 = Mocha.new(beverage2)
    beverage2 = Mocha.new(beverage2)
    beverage2 = Whip.new(beverage2)
    prices << "%-60s $%5.2f" % [ beverage2.description, beverage2.cost() ]

    beverage3 = HouseBlend.new
    beverage3 = Soy.new(beverage3)
    beverage3 = Mocha.new(beverage3)
    beverage3 = Whip.new(beverage3)
    prices << "%-60s $%5.2f" % [ beverage3.description, beverage3.cost() ]

    puts box("Brewed Coffee", prices)
  end

  # UTF-8 encoding table and Unicode characters
  # http://www.utf8-chartable.de/unicode-utf8-table.pl?start=9472&unicodeinhtml=dec
  def self.box(title, bodies, width=80)
    lines = []
    lines << "╔%s╗" % ( "[ #{title} ]".center(width - 2, "═") )
    lines << "║%s║" % ( " " * (width - 2) )
    bodies.each do |body|
      lines << "║%s║" % ( body.center(width - 2, " ") )
    end
    lines << "║%s║" % ( " " * (width - 2) )
    lines << "╚%s╝" % ( "═" * (width - 2) )
    lines.join("\n")
  end
end

if $0 == __FILE__
  StarbuzzCoffee.start()
end

$ ruby starbuzz_ordering_systems.rb 
╔══════════════════════════════[ Brewed Coffee ]═══════════════════════════════╗
║                                                                              ║
║     Espresso                                                     $ 1.99      ║
║     Dark roast coffee, mocha, mocha, whip                        $ 1.49      ║
║     House blend coffee, soy, mocha, whip                         $ 1.34      ║
║                                                                              ║
╚══════════════════════════════════════════════════════════════════════════════╝