{-# LANGUAGE DeriveDataTypeable #-}
{-# LANGUAGE OverloadedStrings  #-}
{-# LANGUAGE RecordWildCards    #-}

import           Control.Monad          (replicateM_)
import           Data.Monoid            ((<>))
import qualified Data.Text              as T
import qualified Data.Text.IO           as TIO (hPutStrLn, putStrLn)
import           System.Console.CmdArgs
import           System.Exit
import           System.IO              (stderr)

import           Text.IPv6Addr

version :: String
version = "1.0.0"

data Input = Input
  { output   :: String
  , address  :: String
  , quantity :: Int
  , prefix   :: String
  } deriving (Show, Data, Typeable)

ip6addrInput :: Input
ip6addrInput = Input
  { address = mempty
    &= typ " <IPv6 address>"
  , output = "canonical"
    &= typ " [canonical|pure|full|arpa|unc|random]"
    &= help "Default : canonical (RFC 5952)"
  , quantity = 1
    &= help "Amount of random addresses to generate"
    &= typ " <Integer>"
  , prefix = ""
    &= typ " <Prefix>"
    &= help "Set a prefix for random addresses generation"
  } &= summary ("ip6addr version " <> version <> " (c) Michel Boucey 2011-2018")
    &= program "ip6addr"
    &= helpArg [name "h"]
    &= details [ "Examples:"
               , ""
               , "  ip6addr -a 0:0::FFFF:192.0.2.128"
               , "  ip6addr -o full -a ::1"
               , "  ip6addr -o random -q 10 -p 1234:abcd::"
               , ""
               ]

main :: IO ()
main = do
  Input{..} <- cmdArgs ip6addrInput
  if output == "random"
    then replicateM_ quantity (putRandAddr prefix) >> exitSuccess
    else
      case output of
        "canonical" -> out maybeIPv6Addr address fromIPv6Addr
        "pure"      -> out maybePureIPv6Addr address fromIPv6Addr
        "full"      -> out maybeFullIPv6Addr address fromIPv6Addr
        "arpa"      -> out maybeIP6ARPA address id
        "unc"       -> out maybeUNC address id
        _           -> TIO.hPutStrLn stderr "See help" >> exitFailure
  where
    putRandAddr p = do
      r <- randIPv6AddrWithPrefix (if p == mempty then Nothing else Just (T.pack p))
      case r of
        Just a  -> TIO.putStrLn (fromIPv6Addr a)
        Nothing -> TIO.putStrLn "Bad prefix"
    out t i o =
      if i /= mempty
        then do
          let p = T.pack i
          case t p of
            Nothing ->
              TIO.hPutStrLn stderr ("'" <> p <> "' is not an IPv6 address") >> exitFailure
            Just a  -> TIO.putStrLn (o a) >> exitSuccess
        else Prelude.putStrLn "See help" >> exitFailure
    maybeUNC t = toUNC <$> maybePureIPv6Addr t
    maybeIP6ARPA t = toIP6ARPA <$> maybeFullIPv6Addr t