require 'test/unit'

require 'forward_referencing'

class LineLink

  attr_accessor :data, :link

  def initialize(chain,data,link)
    @data,@link = data,link
  end

  def to_s
    "#{data} #{link}"
  end

end


class LineChain < ForwardReferencer
  
  attr_accessor :chain

  def load(text)
    @chain = {}
    pattern = /(\w*) (\w*)/
    text.each do |line|
      matches = pattern.match line 
      line_link = LineLink.new self, matches[1], matches[2]
      @chain[line_link.data] = line_link
      forward_reference = create line_link.data
      if ((link = @chain[line_link.link]) != nil) ||
         (line_link.link == 'end')
        line_link.link = link
        remove forward_reference
      end
      continue
    end
  end

end


class TC_Histogram < Test::Unit::TestCase

  def test_forward_referencing
    
    text = <<TEXT_END
eight nine
five six
four five
nine end
one two
seven eight
six seven
start zero
three four
two three
zero one
TEXT_END
    
    line_chain = LineChain.new
    line_chain.load(text)
    dependencies = line_chain.dependencies
    assert(dependencies["start"] != nil)
    assert(dependencies["one"] != nil)
    assert(dependencies["five"] != nil)
    assert(dependencies["eight"] != nil)
    assert(line_chain.remaining == 4)
    assert(line_chain.chain['start'].to_s ==
           'start zero')
    assert(line_chain.chain['zero'].to_s ==
           'zero one two')
    assert(line_chain.chain['one'].to_s ==
           'one two')
    assert(line_chain.chain['two'].to_s ==
           'two three four five six')
    assert(line_chain.chain['three'].to_s ==
           'three four five six')
    assert(line_chain.chain['four'].to_s ==
           'four five six')
    assert(line_chain.chain['five'].to_s ==
           'five six')
    assert(line_chain.chain['six'].to_s ==
           'six seven eight nine')
    assert(line_chain.chain['seven'].to_s ==
           'seven eight nine')
    assert(line_chain.chain['eight'].to_s ==
           'eight nine')
    assert(line_chain.chain['nine'].to_s ==
           'nine ')
    assert(line_chain.chain.size == 11)
    assert(line_chain.to_s == "LineChain  4 unresolved")

    line_chain.resolve
    assert(line_chain.remaining == 0)
    assert(line_chain.chain['start'].to_s ==
           'start zero one two three four five six seven eight nine ')
    assert(line_chain.chain['zero'].to_s ==
           'zero one two three four five six seven eight nine ')
    assert(line_chain.chain['one'].to_s ==
           'one two three four five six seven eight nine ')
    assert(line_chain.chain['two'].to_s ==
           'two three four five six seven eight nine ')
    assert(line_chain.chain['three'].to_s ==
           'three four five six seven eight nine ')
    assert(line_chain.chain['four'].to_s ==
           'four five six seven eight nine ')
    assert(line_chain.chain['five'].to_s ==
           'five six seven eight nine ')
    assert(line_chain.chain['six'].to_s ==
           'six seven eight nine ')
    assert(line_chain.chain['seven'].to_s ==
           'seven eight nine ')
    assert(line_chain.chain['eight'].to_s ==
           'eight nine ')
    assert(line_chain.chain['nine'].to_s ==
           'nine ')
    assert(line_chain.chain.size == 11)
    assert(line_chain.to_s == "LineChain  0 unresolved")
    
  end
  
end