require 'securerandom'
class Trocla
  class Util
    class << self
      def random_str(length=12, charset='default')
        _charsets = charsets[charset] || charsets['default']
        _charsets_size = _charsets_size
        (1..length).collect{|a| _charsets[SecureRandom.random_number(_charsets.size)] }.join.to_s
      end

      def salt(length=8)
        alphanumeric_size = alphanumeric.size
        (1..length).collect{|a| alphanumeric[SecureRandom.random_number(alphanumeric_size)] }.join.to_s
      end

      private

      def charsets
        @charsets ||= {
          'default'       => chars,
          'alphanumeric'  => alphanumeric,
          'shellsafe'     => shellsafe,
        }
      end

      def chars
        @chars ||= shellsafe + special_chars
      end
      def shellsafe
        @chars ||= alphanumeric + shellsafe_chars
      end
      def alphanumeric
        @alphanumeric ||= ('a'..'z').to_a + ('A'..'Z').to_a + ('0'..'9').to_a
      end
      def special_chars
        @special_chars ||= "*()&![]{}-".split(//)
      end
      def shellsafe_chars
        @shellsafe_chars ||= "+%/@=?_.,:".split(//)
      end
    end
  end
end