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

import IPv4Address
import ListUtils
import Maskbits
import Octet


data Cidr = None | Cidr { ipv4address :: IPv4Address,
                          maskbits :: Maskbits }
            deriving (Eq, Show)


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


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


cidr_from_string :: String -> Cidr
cidr_from_string s
    | addr  == IPv4Address.None = Cidr.None
    | mbits == Maskbits.None    = Cidr.None
    | otherwise = Cidr addr mbits
               where
                 addr = ipv4address_from_octets (oct1) (oct2) (oct3) (oct4)
                 oct1 = (octs !! 0)
                 oct2 = (octs !! 1)
                 oct3 = (octs !! 2)
                 oct4 = (octs !! 3)
                 octs  = octets_from_cidr_string s
                 mbits = maskbits_from_cidr_string s