{-# OPTIONS_GHC -Wall #-}
module Main where

import Control.Monad as List (mapM_)
import Control.Monad.Trans (MonadIO(liftIO))
import Data.List (intercalate, isPrefixOf)
import Data.Set.Extra as Set (Set, toList)
import Language.Haskell.Exts.Syntax (ModuleName(ModuleName))
import Language.Haskell.Modules
import Language.Haskell.Modules.ModuVerse (getNames)
import Language.Haskell.Modules.SourceDirs (getDirs)
import System.IO (hGetLine, hPutStr, hPutStrLn, stderr, stdin)

main :: IO ()
main = runCleanT (noisily cli)

cli :: MonadClean m => m ()
cli = liftIO (hPutStr stderr " > " >> hGetLine stdin) >>= cmd . words

cmd :: MonadClean m => [String] -> m ()
cmd [] = cli
cmd (s : args) =
    case filter (any (== s) . fst) cmds of
      [(_, f)] -> f
      -- No exact matches - look for prefix matches
      [] -> case filter (any (isPrefixOf s) . fst) cmds of
              [(_, f)] -> f
              [] -> liftIO (hPutStrLn stderr $
                              show s ++ " invalid - expected " ++ intercalate ", " (concatMap fst cmds)) >> cli
              xs -> liftIO (hPutStrLn stderr $
                              show s ++ " ambiguous - expected " ++ intercalate ", " (concatMap fst xs)) >> cli
      _ -> error $ "Internal error - multiple definitions for " ++ show s
    where
      cmds =
          [(["quit", "exit", "bye", "."],	liftIO (hPutStrLn stderr "Exiting")),
           (["v"],				liftIO (hPutStrLn stderr "Increasing verbosity level") >> noisily cli),
           (["q"],				liftIO (hPutStrLn stderr "Decreasing verbosity level") >> quietly cli),
           (["help"],				liftIO (hPutStrLn stderr "help text") >> cli),
           (["verse"],				verse args >> cli),
           (["clean"],				clean args >> cli),
           (["dir"],				dir args >> cli),
           (["split"],				split args >> cli),
           (["merge"],				merge args >> cli)]

unModuleName :: ModuleName -> String
unModuleName (ModuleName x) = x

verse :: MonadClean m => [String] -> m ()
verse [] =
    do modules <- getNames
       liftIO $ hPutStrLn stderr ("Usage: verse <pathormodule1> <pathormodule2> ...\n" ++
                                  "Add the module or all the modules below a directory to the moduVerse\n" ++
                                  "Currently:\n  " ++ showVerse modules)
verse args =
    do new <- mapM (liftIO . find) args
       List.mapM_ (List.mapM_ putModule) new
       modules <- getNames
       liftIO (hPutStrLn stderr $ "moduVerse updated:\n  " ++ showVerse modules)
    where
      find s =
          do ms <- liftIO (findHsModules [s])
             case ms of
               [] -> return [s]
               _ -> return ms

showVerse :: Set ModuleName -> String
showVerse modules = "[ " ++ intercalate "\n  , " (map unModuleName (toList modules)) ++ " ]"

dir :: MonadClean m => [FilePath] -> m ()
dir [] = putDirs []
dir xs =
    do modifyDirs (++ xs)
       xs' <- getDirs
       liftIO (hPutStrLn stderr $ "sourceDirs updated:\n  [ " ++ intercalate "\n  , " xs' ++ " ]")

clean :: MonadClean m => [FilePath] -> m ()
clean [] = liftIO $ hPutStrLn stderr "Usage: clean <modulepath1> <modulepath2> ..."
clean args = cleanImports args >> return ()

split :: MonadClean m => [FilePath] -> m ()
split [arg] = splitModuleDecls arg >> return ()
split _ = liftIO $ hPutStrLn stderr "Usage: split <modulepath>"

merge :: MonadClean m => [String] -> m ()
merge args =
    case splitAt (length args - 1) args of
      (inputs, [output]) -> mergeModules (map ModuleName inputs) (ModuleName output) >> return ()
      _ -> liftIO $ hPutStrLn stderr "Usage: merge <inputmodulename1> <inputmodulename2> ... <outputmodulename>"