MoneyParser

class MoneyParser

  ONE_TO_TEN = {
      "one" => 1,
      "two" => 2,
      "nine" => 9,
      "five" => 5,
      "four" =>4,
      "seven" => 7,
      "eight" => 8,
      "six" => 6,
      "three" => 3,
      "ten" => 10,
  }
  
  ELEVEN_TO_NINETEEN = {
       "eleven" => 11,
       "twelve" => 12,
       "thirteen" => 13,
       "fourteen" => 14,
       "fifteen" => 15,
       "sixteen" => 16,
       "seventeen" => 17,
       "eighteen" => 18,
       "nineteen" => 19,
  }
  
  TWENTY_TO_NINETY_BY_TEN = {
    "twenty" => 20,
    "thirty" => 30,
    "forty" => 40,
    "fifty" => 50,
    "sixty" => 60,
    "seventy" => 70,
    "eighty" => 80,
    "ninety" => 90
  } 
   

  def self.parse(string)
    string = string.gsub(/ dollar(s)?/i, '')
    if string.match(/\W/)
      total = 0
      string.split(/\W/).each do |string|
        total += self.parse(string)
       
      end
      return total
      
    else
      map[string]
    end
  end
  
  def self.map
    {}.
      merge(ONE_TO_TEN).
      merge(ELEVEN_TO_NINETEEN).
      merge(TWENTY_TO_NINETY_BY_TEN)
  end
end #MoneyParser