Orange Tree Problem

gistfile1.rb

# Make an OrangeTree class. It should have a  height method which returns its height, and a  oneYearPasses method, 
# which, when called, ages the tree one year. Each year the tree grows taller (however much you think an orange tree 
# should grow in a year), and after some number of years (again, your call) the tree should die. For the first few years, 
# it should not produce fruit, but after a while it should, and I guess that older trees produce more each year 
# than younger trees... whatever you think makes most sense. And, of course, you should be able to countTheOranges 
# (which returns the number of oranges on the tree), and pickAnOrange (which reduces the @orangeCount by one and 
# returns a string telling you how delicious the orange was, or else it just tells you that there are no more 
# oranges to pick this year). Make sure that any oranges you don't pick one year fall off before the next year.
class OrangeTree
  
  attr_reader :height
  HEIGHT_PER_YEAR = 2
  MAX_AGE = 6
  DEAD_TREE_MESSAGE = "The tree has died. :( No More Oranges"
  
  def initialize
    @age = 0
    @height = 2
    @oranges = []
  end
  
  def oneYearPasses
    if max_age_reached?
      tree_dies
    else
      increment_age
      increment_height
      grow_fruit
      @age
    end
  end
  
  def orange_count
    @oranges.count
  end
  
  def pick_orange
    @oranges.pop || "No oranges left to pick"
  end
  
  def dead?
    @age.frozen?
  end
  
  private
  
  def tree_dies
    @oranges.freeze
    @age.freeze
    @height.freeze
    
    class << self
      [:pick_orange, :orange_count, :oneYearPasses].each do |m|
        define_method(m) { DEAD_TREE_MESSAGE }
      end
    end
    
    DEAD_TREE_MESSAGE
  end
  
  def max_age_reached?
    @age == MAX_AGE
  end
  
  def increment_age
    @age = @age.next
  end
  
  def increment_height
    @height = @age * HEIGHT_PER_YEAR
  end
  
  # Obviously not how trees produce, but it works
  def grow_fruit
    @oranges = [] # Need to reset the orange count each year
    ([(@age - 3), 0].max * 2).times { @oranges << Orange.new }
  end
  
end

class Orange
  
  def to_s
    "Wow, that is an amazing orange"
  end
  
end