require "string_calculator/version"

module StringCalculator
  def manipulate
    return 0 if empty?
    raise_if_negatives_present if include?("-")
    return array_sum
   end

  def delimiter
   ','
  end

  def digits
   gsub(regular_expression,delimiter).split(delimiter).reject(&:empty?).map(&:to_i)
  end

  def raise_if_negatives_present
   negativies = digits.select{|x| x < 0}
   raise "Negativies not allowed:#{negativies.join(',')}" if negativies.any?
  end

  def array_sum
   sum = 0
   digits.each { |x| sum+=x if x < 1001 }
   sum
  end

  def regular_expression
  /[\n`~!@#$%^&*()_|+\=?;:'",.<>\{\}\[\]\\\/]/
  end
end