module Options where
import System.Console.GetOpt
import Data.Maybe

data HsnsOpts = Opts {
          count         :: String, 
          snarflen      :: String, 
          interface     :: String, 
          version       :: String, 
          nopromiscuous :: String, 
          iflist        :: String, 
          buffered      :: String, 
          help          :: String, 
          bpf           :: String 
}

data Flags =
           Count String    |    -- amount of packets to take, must be String in constructor, that's how getOpt returns it
           IfList          |    -- List the available interfaces
           Listen String   |    -- Listen on the specified interface
           LineBuffered    |    -- Turn on Line buffering
           NoPromiscuous   |    -- Don't go into promiscuous mode.
           SnarfLen String |    -- Amount of data to snarf, default is 68
           Version         |    -- version number
           Help                 -- help info

options :: [OptDescr Flags]
options = [ Option     ['h','?']    ["help"]           (NoArg Help)              "print this help information"
           ,Option     ['c']        ["count"]          (ReqArg Count "NUM")      "take in NUM packets, default is 5, 0 means unlimited"
           ,Option     ['D']        ["iflist"]         (NoArg IfList)            "list interfaces that can be captured upon"
           ,Option     ['i']        ["interface"]      (ReqArg Listen "INT")     "listen on interface INT, defaults to eth0"
           ,Option     ['l']        ["linebuffered"]   (NoArg LineBuffered)      "make output line-buffered"
           ,Option     ['p']        ["nopromiscuous"]  (NoArg NoPromiscuous)     "do not go into promiscuous mode"
           ,Option     ['s']        ["snarf"]          (ReqArg SnarfLen "LEN")   "change snarf length from default 68 to LEN"
           ,Option     ['V']        ["version"]        (NoArg Version)           "output version number and exit"]

hsnsOptions :: [String] -> IO ([Flags],[String])
hsnsOptions av = do
  case getOpt Permute options av of
    (o,n,[]) -> return (o,n)
    (_,_,e)  -> ioError (userError (concat e ++ usageInfo header options))
   where
    header = "usage: hsns \"[PACKET FILTER]\" [OPTIONS...]"