-- ghc-mod: Making Haskell development *more* fun
-- Copyright (C) 2015  Daniel Gröber <dxld ÄT darkboxed DOT org>
--
-- This program is free software: you can redistribute it and/or modify
-- it under the terms of the GNU Affero General Public License as published by
-- the Free Software Foundation, either version 3 of the License, or
-- (at your option) any later version.
--
-- This program is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-- GNU Affero General Public License for more details.
--
-- You should have received a copy of the GNU Affero General Public License
-- along with this program.  If not, see <http://www.gnu.org/licenses/>.

{-# LANGUAGE CPP #-}
module Language.Haskell.GhcMod.CabalHelper (
    getComponents
  , getGhcPkgOptions
  ) where

import Control.Applicative
import Control.Monad
import Data.Monoid
import Data.Version
import Distribution.Helper
import qualified Language.Haskell.GhcMod.Types as T
import Language.Haskell.GhcMod.Types hiding (ghcProgram, ghcPkgProgram,
                                             cabalProgram)
import Language.Haskell.GhcMod.Monad.Types
import Language.Haskell.GhcMod.Utils
import Language.Haskell.GhcMod.World
import Language.Haskell.GhcMod.PathsAndFiles
import System.FilePath

import Paths_ghc_mod as GhcMod

-- | Only package related GHC options, sufficient for things that don't need to
-- access home modules
getGhcPkgOptions :: (MonadIO m, GmEnv m) => m [(ChComponentName, [GHCOption])]
getGhcPkgOptions = do
  Cradle {..} <- cradle
  let distdir = cradleRootDir </> "dist"
  runQuery distdir ghcPkgOptions

helperProgs :: Options -> Programs
helperProgs opts = Programs {
                            cabalProgram  = T.cabalProgram opts,
                            ghcProgram    = T.ghcProgram opts,
                            ghcPkgProgram = T.ghcPkgProgram opts
                          }

-- | Primary interface to cabal-helper and intended single entrypoint to
-- constructing 'GmComponent's
--
-- The Component\'s 'gmcHomeModuleGraph' will be empty and has to be resolved by
-- 'resolveGmComponents'.
getComponents :: (MonadIO m, GmEnv m, GmLog m)
              => m [GmComponent GMCRaw ChEntrypoint]
getComponents = do
  opt <- options
  Cradle {..} <- cradle
  let gmVer = GhcMod.version
      chVer = VERSION_cabal_helper
      d = (helperProgs opt
          , cradleRootDir </> "dist"
          , (gmVer, chVer)
          )
  withCabal $ cached cradleRootDir cabalHelperCache d

cabalHelperCache :: MonadIO m => Cached m
                      (Programs, FilePath, (Version, String))
                      [GmComponent GMCRaw ChEntrypoint]
cabalHelperCache = Cached {
    cacheFile = cabalHelperCacheFile,
    cachedAction = \ _ (progs, root, _) _ ->
      runQuery' progs root $ do
        q <- liftM5 join5
               ghcOptions
               ghcSrcOptions
               ghcLangOptions
               entrypoints
               sourceDirs
        let cs = flip map q $ \(cn, (opts, (srcOpts, (langOpts, (ep, srcDirs))))) ->
                   GmComponent cn opts srcOpts langOpts ep ep srcDirs mempty
        return ([setupConfigPath], cs)
  }
 where
   join5 a b c d = join' a . join' b . join' c . join' d
   join' :: Eq a => [(a,b)] -> [(a,c)] -> [(a,(b,c))]
   join' lb lc = [ (a, (b, c))
                | (a, b) <- lb
                , (a', c) <- lc
                , a == a'
                ]


withCabal :: (MonadIO m, GmEnv m) => m a -> m a
withCabal action = do
    crdl <- cradle
    opts <- options
    liftIO $ whenM (isSetupConfigOutOfDate <$> getCurrentWorld crdl) $
        withDirectory_ (cradleRootDir crdl) $ do
            let progOpts =
                    [ "--with-ghc=" ++ T.ghcProgram opts ]
                    -- Only pass ghc-pkg if it was actually set otherwise we
                    -- might break cabal's guessing logic
                    ++ if T.ghcPkgProgram opts /= T.ghcPkgProgram defaultOptions
                         then [ "--with-ghc-pkg=" ++ T.ghcPkgProgram opts ]
                         else []
            void $ readProcess (T.cabalProgram opts) ("configure":progOpts) ""
            writeAutogenFiles $ cradleRootDir crdl </> "dist"
    action