functions.rb

   def distance_between(obj_a, obj_b)
      p1 = GeoRuby::SimpleFeatures::Point.from_x_y(get_x(obj_a), get_y(obj_a))
      p2 = GeoRuby::SimpleFeatures::Point.from_x_y(get_x(obj_b), get_y(obj_b))
      p1.euclidian_distance(p2)
    end

price_list.rb

class PriceList < ActiveRecord::Base
  self.table_name = 'price_list'

  scope :with_code, lambda{|code|
    where(:code => code)
  }

  def self.method_missing(m)
    var = PriceList.with_code(m.to_s.upcase).first
    if var
      return var.cost
    else
      super
    end
  end
end

travelling_ship.rb

class TravellingShip < MyShip

  attr_accessor :queue

  def modify_speed
    max_speed_allowed = Functions.get_numeric_variable('MAX_SHIP_SPEED')
    if self.distance_from_objective > self.max_speed && self.max_speed < max_speed_allowed
      upgrade_amount_available = max_speed_allowed - self.max_speed

      # TODO: Find the price of refueling
      price_to_refuel = 1
      available_funds = Schemaverse.estimated_income - (Schemaverse.fuel_needed_for_next_tic * price_to_refuel)
      upgrade_amount = available_funds <= upgrade_amount_available * PriceList.max_speed ? upgrade_amount_available : available_funds / PriceList.max_speed
      self.upgrade('MAX_SHIP_SPEED', upgrade_amount.to_i) if upgrade_amount.to_i > 0
    end
  end

  def process_queue
    next_objective = queue.first
    if explorer_ship.course_control(Functions.distance_between(self, next_objective) / 2, nil, next_objective)
      self.objective = next_objective
      queue.shift
    end
  end

end