module Cidr
( Cidr(..),
  cidr_from_string,
  is_valid_cidr
) where

import Text.Regex.Posix

import IPv4Address
import ListUtils
import Octet


data Cidr = Cidr { ipv4address :: IPv4Address,
                   maskbits :: Maskbits }
            deriving (Eq, Show)

-- Will return True if the passed String is in CIDR notation, False
-- otherwise.
is_valid_cidr :: String -> Bool
is_valid_cidr cidr = cidr =~ "([0-9]{1,3}\\.){3}[0-9]{1,3}/[0-9]{1,2}"


-- Returns the mask portion of a CIDR address. That is, everything
-- after the trailing slash.
maskbits_from_string :: String -> Maskbits
maskbits_from_string s = read ((splitWith (`elem` "/") s) !! 1)


-- Takes an IP address String in CIDR notation, and returns a list of
-- its octets (as Ints).
octets_from_string :: String -> [Int]
octets_from_string s = map read (take 4 (splitWith (`elem` "./") s))


cidr_from_string :: String -> Cidr
cidr_from_string s = Cidr addr mbits
               where
                 addr = IPv4Address (oct1) (oct2) (oct3) (oct4)
                 oct1 = octet_from_int (octs !! 0)
                 oct2 = octet_from_int (octs !! 1)
                 oct3 = octet_from_int (octs !! 2)
                 oct4 = octet_from_int (octs !! 3)
                 octs  = octets_from_string s
                 mbits = maskbits_from_string s