module CpfTools

# File lib/cpf_tools.rb, line 25
def format(cpf, format: :masked)
  tax_id = cpf_to_s(cpf)
  return '' unless tax_id.length == 11

  if format == :digits_only
    tax_id
  else
    "#{tax_id[0..2]}.#{tax_id[3..5]}.#{tax_id[6..8]}-#{tax_id[9..10]}"
  end
end

# File lib/cpf_tools.rb, line 36
def return_valid(cpf, format: :masked)
  valid?(cpf) ? format(cpf, format: format) : ''
end

# File lib/cpf_tools.rb, line 8
def valid?(cpf)
  tax_id = cpf_to_s(cpf)

  if invalid_repetition?(tax_id)
    false
  elsif tax_id.length == 11
    id_array = tax_id.split('').map(&:to_i)

    first_digit  = id_multiplier(id_array[0..8])
    second_digit = id_multiplier(id_array[0..9])

    first_digit == id_array[9] && second_digit == id_array[10]
  else
    false
  end
end

# File lib/cpf_tools.rb, line 41
def cpf_to_s(cpf)
  cpf = cpf.to_s if cpf.is_a? Integer
  cpf.scan(/\d*/m).join
end

# File lib/cpf_tools.rb, line 50
def id_multiplier(id)
  multiplier = id.length + 1
  tax_id_base = id.enum_for(:each_with_index).map { |x, idx| x * (multiplier - idx) }.inject(:+)
  result = (tax_id_base * 10) % 11
  result == 10 ? 0 : result
end

# File lib/cpf_tools.rb, line 46
def invalid_repetition?(tax_id)
  tax_id.count('0') == 11 || tax_id.count('9') == 11
end