module Quoridor.Cmdline.Options
  ( Options(..)
  , ExecMode(..)
  , getOptions
  ) where

import           Control.Monad         (unless)
import           Data.Char             (isDigit)
import           Data.Maybe            (fromMaybe, isNothing)
import           System.Environment    (getProgName)
import           System.Exit           (exitFailure, exitSuccess)

import           System.Console.GetOpt (ArgDescr (NoArg, OptArg),
                                        ArgDescr (ReqArg),
                                        ArgOrder (RequireOrder), OptDescr,
                                        OptDescr (Option), getOpt, usageInfo)

import           Quoridor.Helpers      (andP)

-- | Represents possible options from the cmdline
data Options = Options
  { opBoardSize      :: Int
  , opNumOfPlayers   :: Int
  , opGatesPerPlayer :: Int
  , opHostListenAddr :: String
  , opHostListenPort :: Int
  , opHttpListenPort :: Int
  , opExecMode       :: ExecMode
  }

-- | Represents an execution mode for the program.
-- One can run quoridor at local play, server host or client join modes
data ExecMode = ExLocal | ExHost | ExJoin | ExProxy
  deriving Eq

defaultOptions :: Options
defaultOptions = Options
  { opBoardSize      = 9
  , opNumOfPlayers   = 2
  , opGatesPerPlayer = 10
  , opHostListenAddr = "127.0.0.1"
  , opHostListenPort = 33996
  , opHttpListenPort = 33997
  , opExecMode       = ExLocal
  }

-- exported functions

-- | Given the args from the cmdline,
-- returns them parsed into an Options data value.
-- It runs in the IO monad to allow the ability to exit the program
-- if something fails in the parsing (upon which, a usageInfo will be displayed)
getOptions :: [String] -> IO Options
getOptions args = do
  let (actions, _, _) = getOpt RequireOrder options args
  foldl (>>=) (return defaultOptions) actions



--helpers

isInRange :: Ord a => a -> a -> a -> Bool
isInRange a b c = ((>= b) `andP` (<= c)) a

putUsageInfoLn :: IO ()
putUsageInfoLn = do
  prg <- getProgName
  putStrLn (usageInfo prg options)

options :: [ OptDescr (Options -> IO Options) ]
options =
  [ Option "b" ["board-size"]
      (ReqArg
          (\arg opts -> do
            argNum <- rangedOption 2 9 arg
            return opts { opBoardSize = argNum })
          "INTEGER")
      "Board size (2-9 rows/columns). default 9"

  , Option "n" ["number-of-players"]
      (ReqArg
          (\arg opts -> do
            argNum <- rangedOption 2 4 arg
            return opts { opNumOfPlayers = argNum })
          "INTEGER")
      "Number of players (2-4 players). default 2"

  , Option "g" ["gates-per-player"]
      (ReqArg
          (\arg opts -> do
            argNum <- rangedOption 0 100 arg
            return opts { opGatesPerPlayer = argNum })
          "INTEGER")
      "Gates per player (1-100 gates per player). default 10"

  , Option "l" ["local"]
      (NoArg $
          \opts -> return opts { opExecMode = ExLocal })
      "Start a local game"

  , Option "h" ["host"]
      (portOptionArg ExHost)
      "Host a game server. default port 33996"

  , Option "j" ["join"]
      (portOptionArg ExJoin)
      "Join a game server"

  , Option "p" ["client-proxy"]
      (portOptionArg ExProxy)
      "Client acts as proxy for a browser (used by the http server)"

  , Option "t" ["http-port"]
      (ReqArg
          (\arg opts -> do
            argNum <- rangedOption 1025 65535 arg
            return opts { opHttpListenPort = argNum })
          "PORT")
      "A port for the http-server (port 1025-65535), relevant only if --host flag is used. default 33997"

  , Option "?" ["help"]
      (NoArg $
          \_ -> do
            putUsageInfoLn
            exitSuccess)
      "Show help"
  ]
 where portOptionArg execMode =
         OptArg
             (\arg opts -> do
                let mAddr = getAddr =<< arg
                    addr  = fromMaybe (opHostListenAddr opts) mAddr
                    mPort = getPort =<< arg
                port <- maybe (return $ opHostListenPort opts)
                  (rangedOption 1025 65535 . show) mPort
                return opts
                  { opExecMode       = execMode
                  , opHostListenPort = port
                  , opHostListenAddr = addr
                  })
              "ADDR/PORT (either or both)"

       rangedOption x y arg = do
         let argNum = read arg
         unless (isInRange argNum x y) $ do
           putUsageInfoLn
           exitFailure
         return argNum

       getAddr s | ':' `elem` s = Just $ takeWhile (/= ':') s
                 | isNothing $ getPort s = Just s
                 | otherwise = Nothing

       getPort s | length s <= 5 && isNum s = Just (read s :: Int)
                 | ':' `elem` s = getPort $ tail $ dropWhile (/= ':') s
                 | otherwise = Nothing
        where isNum = all isDigit