module Language.Haskell.GhcMod.Debug (debugInfo, debug, rootInfo, root) where

import Control.Applicative
import Control.Exception.IOChoice
import Control.Monad
import Data.List (intercalate)
import Data.Maybe
import GHC
import GhcMonad (liftIO)
import Language.Haskell.GhcMod.CabalApi
import Language.Haskell.GhcMod.GHCApi
import Language.Haskell.GhcMod.Types
import Prelude

----------------------------------------------------------------

-- | Obtaining debug information.
debugInfo :: Options
          -> Cradle
          -> FilePath   -- ^ A target file.
          -> IO String
debugInfo opt cradle fileName = unlines <$> withGHC fileName (debug opt cradle fileName)

-- | Obtaining debug information.
debug :: Options
      -> Cradle
      -> FilePath     -- ^ A target file.
      -> Ghc [String]
debug opt cradle fileName = do
    CompilerOptions gopts incDir pkgs <-
        if cabal then
            liftIO (fromCabalFile ||> return simpleCompilerOption)
          else
            return simpleCompilerOption
    void $ initializeFlagsWithCradle opt cradle gopts True
    setTargetFiles [fileName]
    return [
        "Root directory:      " ++ rootDir
      , "Current directory:   " ++ currentDir
      , "Cabal file:          " ++ cabalFile
      , "GHC options:         " ++ unwords gopts
      , "Include directories: " ++ unwords incDir
      , "Dependent packages:  " ++ (intercalate ", " $ map fst pkgs)
      ]
  where
    currentDir = cradleCurrentDir cradle
    mCabalFile = cradleCabalFile cradle
    mCabalDir = cradleCabalDir cradle
    rootDir = fromMaybe currentDir mCabalDir
    cabal = isJust mCabalFile
    cabalFile = fromMaybe "" mCabalFile
    origGopts = ghcOpts opt
    simpleCompilerOption = CompilerOptions origGopts [] []
    fromCabalFile = parseCabalFile file >>= getCompilerOptions origGopts cradle
      where
        file = fromJust mCabalFile

----------------------------------------------------------------

-- | Obtaining root information.
rootInfo :: Options
          -> Cradle
          -> FilePath   -- ^ A target file.
          -> IO String
rootInfo opt cradle fileName = withGHC fileName (root opt cradle fileName)

-- | Obtaining root information.
root :: Options
      -> Cradle
      -> FilePath     -- ^ A target file.
      -> Ghc String
root _ cradle _ = do
    return $ rootDir ++ "\n"
  where
    currentDir = cradleCurrentDir cradle
    mCabalDir = cradleCabalDir cradle
    rootDir = fromMaybe currentDir mCabalDir