# Generic Module 11 validator
 
class Module11
protected
   #returns the next validation 'digit' of the 'input'. 
   #It will calcultes the next 'digit' based on the 
   #given 'formula' (as block)   
   def Module11.getDigit (input, formula)
      digit = 0
      input.each_with_index do |item, index|
         #passing the current item, its index and the whole array 
         #to the formula
         digit += formula.call(item, index, input)    
      end   
      digit = 11 - (digit % 11)
      digit = 0 if digit > 9
 
      return digit
   end      
 
   #calculates the new 'input' digits based on the given 'formula' 
   #and the 'size' of the desired 'output' array
   def Module11.calculate (input, formula, size)      
      output = Array.new (input)
      while output.size < size do
         output << getDigit(output, formula)
      end
      return output
   end
 
public
   attr_reader :value
 
   def initialize(input, formula, size, number_of_digits)      
      if input.kind_of? String
         @value = input.scan(/\d/).collect{ |item| item.to_i }       
      else
         @value = [0]
      end
 
      if formula.kind_of? Proc
         @formula = formula
      else
         @formula = nil
      end      
 
      if size.kind_of? Fixnum
         @size = size
      else
         @size = 0
      end
 
      if number_of_digits.kind_of? Fixnum
         @number_of_digits = number_of_digits
      else
         @number_of_digits = 0
      end
 
      if (@size > 0) and (@value.size > 0) and (@number_of_digits > 0) and (not @formula.nil?)
         @result = Module11.calculate(@value[0,@size-@number_of_digits], @formula, @size)
      else
         @result = []
      end
   end
 
   def inspect
      "< @value = " + @value.to_s + ">"
   end
 
   def to_s
      @value.join("")
   end
 
   def is_valid?
      @value == @result
   end
 
   def validated
      if is_valid?      
         self
      else        
         Module11.new @result.join, @formula, @size, @number_of_digits
      end   
   end
 
   def is_obvious?   
      @result.join("").to_i % ("1"*@size).to_i == 0
   end
 
   def digits
      if @value.size == @size
         @value[@size-@number_of_digits, @number_of_digits]
      else
         []
      end
   end
 
end
 
class Cpf < Module11
private
   def Cpf.formula
      Proc.new do |item, index, updatedInput|
         item * (updatedInput.size + 1 - index)
      end
   end
 
public
   def initialize(input)            
      super input, Cpf.formula, 11, 2  
   end
 
   def validated
      if is_valid?      
         self
      else        
         Cpf.new @result.join
      end   
   end
end
 
class Cnpj < Module11
private
   def Cnpj.formula
      Proc.new do |item, index, updatedInput|
         coefs = [6, 5, 4, 3, 2, 9, 8, 7, 6, 5, 4, 3, 2]
         item * coefs[index+13-updatedInput.size]
      end
   end
 
public
   def initialize(input)
      super input, Cnpj.formula, 14, 2 
   end
 
   def validated
      if is_valid?      
         self
      else        
         Cnpj.new @result.join
      end   
   end
end