Host.hs

   1 -- This file is part of htalkat
   2 -- Copyright (C) 2021 Martin Bays <mbays@sdf.org>
   3 --
   4 -- This program is free software: you can redistribute it and/or modify
   5 -- it under the terms of version 3 of the GNU General Public License as
   6 -- published by the Free Software Foundation, or any later version.
   7 --
   8 -- You should have received a copy of the GNU General Public License
   9 -- along with this program.  If not, see http://www.gnu.org/licenses/.
  10
  11 {-# LANGUAGE Safe #-}
  12
  13 module Host where
  14
  15 import           Control.Monad (msum)
  16 import           Data.List     (elemIndices)
  17 import           Data.Maybe    (fromMaybe)
  18 import           Safe          (lastMay, readMay)
  19
  20 data Host = Host {hostName :: String, hostPort :: Int}
  21     deriving (Eq,Ord,Show)
  22
  23 defaultTalkatPort :: Int
  24 defaultTalkatPort = 5518
  25
  26 showHost :: Host -> String
  27 showHost (Host name port) = name ++
  28     (if port == defaultTalkatPort then "" else ":" ++ show port)
  29
  30 parseHost :: String -> Maybe Host
  31 parseHost s = msum
  32     [ (`Host` defaultTalkatPort) <$> decodeIPv6 s
  33     , do
  34         i <- lastMay $ elemIndices ':' s
  35         let (h, ':':portStr) = splitAt i s
  36             h' = fromMaybe h $ decodeIPv6 h
  37         Host h' <$> readMay portStr
  38     , pure $ Host s defaultTalkatPort
  39     ]
  40     where
  41     decodeIPv6 :: String -> Maybe String
  42     decodeIPv6 ('[':rest) | Just ']' <- lastMay rest = Just $ init rest
  43     decodeIPv6 _ = Nothing