{-# LANGUAGE RankNTypes #-}

-- This program must be called with GHC's libdir and the file to be checked as
-- the command line arguments.
module CheckUtils where

import Data.Data
import Data.List
import System.IO
import GHC
import BasicTypes
import DynFlags
import MonadUtils
import Outputable
import ApiAnnotation
import Bag (filterBag,isEmptyBag)
import System.Directory (removeFile)
import System.Environment( getArgs )
import qualified Data.Map as Map
import qualified Data.Set as Set
import Data.Dynamic ( fromDynamic,Dynamic )

_main::IO()
_main = do
        [libdir,fileName] <- getArgs
        testOneFile libdir fileName

testOneFile libdir fileName = do
       ((anns,cs),p) <- runGhc (Just libdir) $ do
                        dflags <- getSessionDynFlags
                        setSessionDynFlags dflags
                        let mn =mkModuleName fileName
                        addTarget Target { targetId = TargetModule mn
                                         , targetAllowObjCode = True
                                         , targetContents = Nothing }
                        load LoadAllTargets
                        modSum <- getModSummary mn
                        p <- parseModule modSum
                        return (pm_annotations p,p)

       let spans = Set.fromList $ getAllSrcSpans (pm_parsed_source p)

           problems = filter (\(s,a) -> not (Set.member s spans))
                             $ getAnnSrcSpans (anns,cs)

           exploded = [((kw,ss),[anchor])
                      | ((anchor,kw),sss) <- Map.toList anns,ss <- sss]

           exploded' = Map.toList $ Map.fromListWith (++) exploded

           problems' = filter (\(_,anchors)
                                -> not (any (\a -> Set.member a spans) anchors))
                              exploded'

       putStrLn "---Problems---------------------"
       putStrLn (intercalate "\n" [showAnns $ Map.fromList $ map snd problems])
       putStrLn "---Problems'--------------------"
       putStrLn (intercalate "\n" [pp $ Map.fromList $ map fst problems'])
       putStrLn "--------------------------------"
       putStrLn (intercalate "\n" [showAnns anns])

    where
      getAnnSrcSpans :: ApiAnns -> [(SrcSpan,(ApiAnnKey,[SrcSpan]))]
      getAnnSrcSpans (anns,_) = map (\a@((ss,_),_) -> (ss,a)) $ Map.toList anns

      getAllSrcSpans :: (Data t) => t -> [SrcSpan]
      getAllSrcSpans ast = everything (++) ([] `mkQ` getSrcSpan) ast
        where
          getSrcSpan :: SrcSpan -> [SrcSpan]
          getSrcSpan ss = [ss]


showAnns anns = "[\n" ++ (intercalate "\n"
   $ map (\((s,k),v)
              -> ("(AK " ++ pp s ++ " " ++ show k ++" = " ++ pp v ++ ")\n"))
   $ Map.toList anns)
    ++ "]\n"

pp a = showPpr unsafeGlobalDynFlags a


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

-- Copied from syb for the test


-- | Generic queries of type \"r\",
--   i.e., take any \"a\" and return an \"r\"
--
type GenericQ r = forall a. Data a => a -> r


-- | Make a generic query;
--   start from a type-specific case;
--   return a constant otherwise
--
mkQ :: ( Typeable a
       , Typeable b
       )
    => r
    -> (b -> r)
    -> a
    -> r
(r `mkQ` br) a = case cast a of
                        Just b  -> br b
                        Nothing -> r



-- | Summarise all nodes in top-down, left-to-right order
everything :: (r -> r -> r) -> GenericQ r -> GenericQ r

-- Apply f to x to summarise top-level node;
-- use gmapQ to recurse into immediate subterms;
-- use ordinary foldl to reduce list of intermediate results

everything k f x = foldl k (f x) (gmapQ (everything k f) x)