----------------------------------------------------------------------
-- |
-- Module      : Update
-- Maintainer  : AR
-- Stability   : (stable)
-- Portability : (portable)
--
-- > CVS $Date: 2005/05/30 18:39:44 $ 
-- > CVS $Author: aarne $
-- > CVS $Revision: 1.8 $
--
-- (Description of the module)
-----------------------------------------------------------------------------

module GF.Compile.Update (buildAnyTree, extendModule, rebuildModule) where

import GF.Infra.Ident
import GF.Infra.Option
import GF.Infra.CheckM
import GF.Grammar.Grammar
import GF.Grammar.Printer
import GF.Grammar.Lookup

import GF.Data.Operations

import Data.List
import qualified Data.Map as Map
import Control.Monad
import GF.Text.Pretty

-- | combine a list of definitions into a balanced binary search tree
buildAnyTree :: Monad m => Ident -> [(Ident,Info)] -> m (BinTree Ident Info)
buildAnyTree m = go Map.empty
  where
    go map []         = return map
    go map ((c,j):is) = do
      case Map.lookup c map of
        Just i  -> case unifyAnyInfo m i j of
		     Ok k  -> go (Map.insert c k map) is
		     Bad _ -> fail $ render ("conflicting information in module"<+>m $$
		                             nest 4 (ppJudgement Qualified (c,i)) $$
		                             "and" $+$
		                             nest 4 (ppJudgement Qualified (c,j)))
        Nothing -> go (Map.insert c j map) is

extendModule :: FilePath -> SourceGrammar -> SourceModule -> Check SourceModule
extendModule cwd gr (name,m)
  ---- Just to allow inheritance in incomplete concrete (which are not
  ---- compiled anyway), extensions are not built for them.
  ---- Should be replaced by real control. AR 4/2/2005
  | mstatus m == MSIncomplete && isModCnc m = return (name,m)
  | otherwise                               = checkInModule cwd m NoLoc empty $ do
                                                 m' <- foldM extOne m (mextend m) 
                                                 return (name,m')
 where
   extOne mo (n,cond) = do
     m0 <- lookupModule gr n

     -- test that the module types match, and find out if the old is complete
     unless (sameMType (mtype m) (mtype mo)) 
            (checkError ("illegal extension type to module" <+> name))

     let isCompl = isCompleteModule m0

     -- build extension in a way depending on whether the old module is complete
     js1 <- extendMod gr isCompl ((n,m0), isInherited cond) name (jments mo)

     -- if incomplete, throw away extension information
     return $ 
          if isCompl
            then mo {jments = js1}
            else mo {mextend= filter ((/=n) . fst) (mextend mo)
                    ,mexdeps= nub (n : mexdeps mo)
                    ,jments = js1
                    }

-- | rebuilding instance + interface, and "with" modules, prior to renaming. 
-- AR 24/10/2003
rebuildModule :: FilePath -> SourceGrammar -> SourceModule -> Check SourceModule
rebuildModule cwd gr mo@(i,mi@(ModInfo mt stat fs_ me mw ops_ med_ msrc_ env_ js_)) =
  checkInModule cwd mi NoLoc empty $ do

----  deps <- moduleDeps ms
----  is   <- openInterfaces deps i
  let is = [] ---- the method above is buggy: try "i -src" for two grs. AR 8/3/2005
  mi'  <- case mw of

    -- add the information given in interface into an instance module
    Nothing -> do
      unless (null is || mstatus mi == MSIncomplete) 
             (checkError ("module" <+> i <+> 
                          "has open interfaces and must therefore be declared incomplete"))
      case mt of
        MTInstance (i0,mincl) -> do
          m1 <- lookupModule gr i0
          unless (isModRes m1)
                 (checkError ("interface expected instead of" <+> i0))
          js' <- extendMod gr False ((i0,m1), isInherited mincl) i (jments mi)
          --- to avoid double inclusions, in instance I of I0 = J0 ** ...
          case extends mi of
            []  -> return mi{jments=js'}
            j0s -> do
                m0s <- mapM (lookupModule gr) j0s
                let notInM0 c _  = all (not . isInBinTree c . jments) m0s
                let js2 = filterBinTree notInM0 js'
                return mi{jments=js2}
        _ -> return mi

    -- add the instance opens to an incomplete module "with" instances
    Just (ext,incl,ops) -> do
      let (infs,insts) = unzip ops
      let stat' = ifNull MSComplete (const MSIncomplete)
                    [i | i <- is, notElem i infs]
      unless (stat' == MSComplete || stat == MSIncomplete) 
             (checkError ("module" <+> i <+> "remains incomplete"))
      ModInfo mt0 _ fs me' _ ops0 _ fpath _ js <- lookupModule gr ext
      let ops1 = nub $
                   ops_ ++ -- N.B. js has been name-resolved already
                   [OQualif i j | (i,j) <- ops] ++
                   [o | o <- ops0, notElem (openedModule o) infs] ++
                   [OQualif i i | i <- insts] ++
                   [OSimple i   | i <- insts]

      --- check if me is incomplete
      let fs1 = fs `addOptions` fs_                           -- new flags have priority
      let js0 = [(c,globalizeLoc fpath j) | (c,j) <- tree2list js, isInherited incl c]
      let js1 = buildTree (tree2list js_ ++ js0)
      let med1= nub (ext : infs ++ insts ++ med_)
      return $ ModInfo mt0 stat' fs1 me Nothing ops1 med1 msrc_ env_ js1

  return (i,mi')

-- | When extending a complete module: new information is inserted,
-- and the process is interrupted if unification fails.
-- If the extended module is incomplete, its judgements are just copied.
extendMod :: SourceGrammar ->
             Bool -> (SourceModule,Ident -> Bool) -> Ident -> 
             BinTree Ident Info -> Check (BinTree Ident Info)
extendMod gr isCompl ((name,mi),cond) base new = foldM try new $ Map.toList (jments mi) 
  where
    try new (c,i0)
      | not (cond c) = return new
      | otherwise    = case Map.lookup c new of
                         Just j -> case unifyAnyInfo name i j of
		                     Ok k  -> return $ updateTree (c,k) new
		                     Bad _ -> do (base,j) <- case j of 
		                                               AnyInd _ m -> lookupOrigInfo gr (m,c)
		                                               _          -> return (base,j)
		                                 (name,i) <- case i of 
                                                               AnyInd _ m -> lookupOrigInfo gr (m,c)
                                                               _          -> return (name,i)
		                                 checkError ("cannot unify the information" $$ 
		                                             nest 4 (ppJudgement Qualified (c,i)) $$
		                                             "in module" <+> name <+> "with" $$
		                                             nest 4 (ppJudgement Qualified (c,j)) $$
		                                             "in module" <+> base)
                         Nothing-> if isCompl
                                     then return $ updateTree (c,indirInfo name i) new
                                     else return $ updateTree (c,i) new
      where
        i = globalizeLoc (msrc mi) i0

    indirInfo :: Ident -> Info -> Info
    indirInfo n info = AnyInd b n' where 
      (b,n') = case info of
        ResValue _ -> (True,n)
        ResParam _ _ -> (True,n)
        AbsFun _ _ Nothing _ -> (True,n) 
        AnyInd b k -> (b,k)
        _ -> (False,n) ---- canonical in Abs

globalizeLoc fpath i =
  case i of
    AbsCat mc             -> AbsCat (fmap gl mc)
    AbsFun mt ma md moper -> AbsFun (fmap gl mt) ma (fmap (fmap gl) md) moper
    ResParam mt mv        -> ResParam (fmap gl mt) mv
    ResValue t            -> ResValue (gl t)
    ResOper mt m          -> ResOper (fmap gl mt) (fmap gl m)
    ResOverload ms os     -> ResOverload ms (map (\(x,y) -> (gl x,gl y)) os)
    CncCat mc md mr mp mpmcfg-> CncCat (fmap gl mc) (fmap gl md) (fmap gl mr) (fmap gl mp) mpmcfg
    CncFun m  mt md mpmcfg-> CncFun m (fmap gl mt) (fmap gl md) mpmcfg
    AnyInd b m            -> AnyInd b m
  where
    gl (L loc0 x) = loc `seq` L (External fpath loc) x
      where
        loc = case loc0 of
                External _ loc -> loc
                loc            -> loc

unifyAnyInfo :: Ident -> Info -> Info -> Err Info
unifyAnyInfo m i j = case (i,j) of
  (AbsCat mc1, AbsCat mc2) -> 
    liftM AbsCat (unifyMaybeL mc1 mc2)
  (AbsFun mt1 ma1 md1 moper1, AbsFun mt2 ma2 md2 moper2) -> 
    liftM4 AbsFun (unifyMaybeL mt1 mt2) (unifAbsArrity ma1 ma2) (unifAbsDefs md1 md2) (unifyMaybe moper1 moper2) -- adding defs

  (ResParam mt1 mv1, ResParam mt2 mv2) ->
    liftM2 ResParam (unifyMaybeL mt1 mt2) (unifyMaybe mv1 mv2)
  (ResValue (L l1 t1), ResValue (L l2 t2)) 
      | t1==t2    -> return (ResValue (L l1 t1))
      | otherwise -> fail ""
  (_, ResOverload ms t) | elem m ms ->
    return $ ResOverload ms t
  (ResOper mt1 m1, ResOper mt2 m2) -> 
    liftM2 ResOper (unifyMaybeL mt1 mt2) (unifyMaybeL m1 m2)

  (CncCat mc1 md1 mr1 mp1 mpmcfg1, CncCat mc2 md2 mr2 mp2 mpmcfg2) -> 
    liftM5 CncCat (unifyMaybeL mc1 mc2) (unifyMaybeL md1 md2) (unifyMaybeL mr1 mr2) (unifyMaybeL mp1 mp2)  (unifyMaybe mpmcfg1 mpmcfg2)
  (CncFun m mt1 md1 mpmcfg1, CncFun _ mt2 md2 mpmcfg2) -> 
    liftM3 (CncFun m) (unifyMaybeL mt1 mt2) (unifyMaybeL md1 md2) (unifyMaybe mpmcfg1 mpmcfg2)

  (AnyInd b1 m1, AnyInd b2 m2) -> do
    testErr (b1 == b2) $ "indirection status"
    testErr (m1 == m2) $ "different sources of indirection"
    return i

  _ -> fail "informations"

-- | this is what happens when matching two values in the same module
unifyMaybeL :: Eq a => Maybe (L a) -> Maybe (L a) -> Err (Maybe (L a))
unifyMaybeL = unifyMaybeBy unLoc

unifAbsArrity :: Maybe Int -> Maybe Int -> Err (Maybe Int)
unifAbsArrity = unifyMaybe

unifAbsDefs :: Maybe [L Equation] -> Maybe [L Equation] -> Err (Maybe [L Equation])
unifAbsDefs (Just xs) (Just ys) = return (Just (xs ++ ys))
unifAbsDefs Nothing   Nothing   = return Nothing
unifAbsDefs _         _         = fail ""
