DAG Dot Generator

# Class: Node
# Description: Contains relevant information related to node
#              Generates conditional probability distribution table
#              Generates dot schema
class Node
  attr_reader :parents
    attr_accessor :label, :values, :id

    def initialize
      @label = nil
      @parents = []
      @values = []
    end

    def add_parent(parent)
      @parents << parent
    end

    #generate conditional probability distribution table
    def cpd
      cpd = []
      labels = @values.map{|i| i.strip }
      cpd << [0.0] * @values.length

      @parents.reverse.each do |parent|
        tmp = []
        labels = [parent.label] + labels
      parent.values.each do |val|
        tmp = tmp + Array.new(cpd).map{|i| [val.strip] + i}
      end
      cpd = tmp
      end
      cpd = [labels] + cpd
      return cpd
    end

    def get_dot
      self.id.to_s + " [shape=none, margin=0, label=<" + get_dot_table + '>]'
    end

    private
      def get_dot_table
        table = cpd
        output= '<TABLE>' + "\n"
        output = output + '<TR><TD COLSPAN="' + table.first.length.to_s + '">' + label + '</TD></TR>' + "\n"
        table.each do |row|
            output = output + '<TR>' + row.map{|i| "<TD>#{i}</TD>"}.join() + '</TR>' + "\n"
        end
        output = output + '</TABLE>'
      end

end

#Helper method to convert string to label
def get_label(text)
  text.strip
end


ids=['A','B','C','D','E','F','G','H']
nodes = {}
read_edge = false

#open file
File.open(ARGV[0]).each do |line|
  line = line.to_s.chomp.strip
  next unless line.length > 0

  #check if we are reading edges or nodes
  read_edge = true if !read_edge and line.downcase == "#edges"

  #read edge
  if read_edge
      tokens = line.split('->').reverse
      (0..tokens.length-2).each do |index|
        child = nodes[get_label tokens[index]]
        parent = nodes[get_label tokens[index+1]]
        if child and parent
           child.add_parent(parent)
        elsif !child
          puts "ERROR: MISSING #{tokens[index]}"
          exit
        elsif !parent
          puts "ERROR: MISSING #{tokens[index]}"
          exit
        end
      end

  # read nodes
  else
      node = Node.new
      tokens = line.split(',')
      node.label = get_label(tokens.shift)
      node.values = tokens
      node.id = ids[nodes.length]
      nodes[node.label] = node
  end
end

#Generate dot notation
puts "digraph g{\n"

nodes.each do |key, value|
  value.parents.each do |parent|
    puts parent.id + " -> " + value.id
  end
end

nodes.each do |key, value|
  puts value.get_dot
end
puts "}"