module Engine (
  crafty, gnuchess,
  engineStart,
  engineStop,
  engineSendCmd
) where

import System.Exit
import System.IO
import System.Process

data Engine = Engine Name FilePath

data EngineHandle = EngineHandle Handle Handle ProcessHandle

type Name = String

crafty :: Engine
crafty = Engine "Crafty" "/usr/local/bin/crafty"

gnuchess :: Engine
gnuchess = Engine "GNUChess" "/usr/local/bin/gnuchess"

engineStart :: Engine -> IO EngineHandle
engineStart (Engine name path) = do
  putStrLn $ "Starting engine \"" ++ name ++ "\""
  (inp,outp,_,pid) <- runInteractiveProcess path [] Nothing Nothing
  hSetBuffering inp LineBuffering
  hSetBuffering outp LineBuffering
  return (EngineHandle inp outp pid)

engineStop :: EngineHandle -> IO ExitCode
engineStop (EngineHandle _ _ pid) = do
  terminateProcess pid
  waitForProcess pid

-- Send a command to a chess engine.
engineSendCmd :: EngineHandle -> String -> IO ()
engineSendCmd (EngineHandle inp _ _) cmd = hPutStrLn inp cmd