import           Control.Monad.M
import qualified Data.List as L
import qualified Data.Set as S
import qualified Distribution.Package as C
import qualified Options as O
import           Options.Applicative
import           Options.Cabal
import           Options.Documentation
import           Pipe.Conf
import           Pipe.FileSystem
import           Pipes
import           System.Environment
    
-- | This yields requested packages from command line and cabal file, if any.
prod_Dependencies :: O.Options -> ProducerM C.Dependency () 
prod_Dependencies options = do
  cabal_deps <- lift cabalDeps
  let deps = cabal_deps ++ O.packages options
  if L.null deps then 
    liftIO $ putStrLn "quitting due to no package dependencies evaluated"
  else
    each . nub' $ deps
  where
    -- This produces a version disjoint package list from the cabal file.
    cabalDeps :: M [C.Dependency]
    cabalDeps =  
      maybe 
        (return []) (`readPackages` (S.fromList $ O.cabalExclusions options)) $
        O.cabalFile options

main :: IO ()
main = do 
  args <- getArgs
  case L.partition (== "help") args of
    ([], args') -> do
      options <- handleParseResult $ execParserPure (prefs idm) parserInfo args'

      runM (newEnv (not . O.quiet $ options)) . runEffect $
        -- writes converted html, haddock, and sql db
        cons_writeFiles (O.outputDir options) 
        <-< pipe_PackageConf options  -- yields vetted package configs
        <-< prod_Dependencies options -- produces dependencies from options 
    (_, rest) -> toHelp docs rest
  
  where 
   parserInfo :: ParserInfo O.Options
   parserInfo = info (helper <*> O.parser)  $
     header "dash-haskell v1.1.0.1, a dash docset construction tool for Haskell packages"
     <> progDesc "additional help is available with \"dash-haskell help <topic|option>\""
     <> footer "http://www.github.com/jfeltz/dash-haskell (C) John P. Feltz 2014, 2015"