----------------------------------------------------------------------
-- |
-- Module      : Modules
-- Maintainer  : AR
-- Stability   : (stable)
-- Portability : (portable)
--
-- > CVS $Date: 2005/02/24 11:46:35 $ 
-- > CVS $Author: peb $
-- > CVS $Revision: 1.20 $
--
-- Datastructures and functions for modules, common to GF and GFC.
--
-- AR 29\/4\/2003
--
-- The same structure will be used in both source code and canonical.
-- The parameters tell what kind of data is involved.
-- Invariant: modules are stored in dependency order
-----------------------------------------------------------------------------

module Modules (MGrammar(..), ModInfo(..), Module(..), ModuleType(..), MReuseType(..),
		extendm, updateMGrammar, updateModule, replaceJudgements,
		addOpenQualif, flagsModule, allFlags, mapModules,
		MainGrammar(..), MainConcreteSpec(..), OpenSpec(..), OpenQualif(..),
		oSimple, oQualif,
		ModuleStatus(..),
		openedModule, allOpens, depPathModule, allDepsModule, partOfGrammar,
		allExtends, allExtendsPlus, allExtensions, searchPathModule, addModule,
		emptyMGrammar, emptyModInfo, emptyModule,
		IdentM(..),
		typeOfModule, abstractOfConcrete, abstractModOfConcrete,
		lookupModule, lookupModuleType, lookupModMod, lookupInfo,
		allModMod, isModAbs, isModRes, isModCnc, isModTrans,
		sameMType, isCompilableModule, isCompleteModule,
		allAbstracts, greatestAbstract, allResources, greatestResource, allConcretes
	       ) where

import Ident
import Option
import Operations

import List


-- AR 29/4/2003

-- The same structure will be used in both source code and canonical.
-- The parameters tell what kind of data is involved.
-- Invariant: modules are stored in dependency order

data MGrammar i f a = MGrammar {modules :: [(i,ModInfo i f a)]}
  deriving Show

data ModInfo i f a =
    ModMainGrammar (MainGrammar i)
  | ModMod  (Module i f a)
  | ModWith (ModuleType i) ModuleStatus i [i] [OpenSpec i]
  deriving Show

data Module i f a = Module {
    mtype   :: ModuleType i ,
    mstatus :: ModuleStatus ,
    flags   :: [f] ,
    extends :: [i],
    opens   :: [OpenSpec i] ,
    jments  :: BinTree (i,a)
  }
  deriving Show

-- | encoding the type of the module
data ModuleType i = 
    MTAbstract 
  | MTTransfer (OpenSpec i) (OpenSpec i) 
  | MTResource
  | MTConcrete i
    -- ^ up to this, also used in GFC. Below, source only.
  | MTInterface
  | MTInstance i 
  | MTReuse (MReuseType i)
  | MTUnion (ModuleType i) [(i,[i])] -- ^ not meant to be recursive
  deriving (Eq,Show)

data MReuseType i = MRInterface i | MRInstance i i | MRResource i
  deriving (Show,Eq)

-- | previously: single inheritance
extendm :: Module i f a -> Maybe i
extendm m = case extends m of
  [i] -> Just i
  _   -> Nothing

-- destructive update

-- | dep order preserved since old cannot depend on new
updateMGrammar :: Ord i => MGrammar i f a -> MGrammar i f a -> MGrammar i f a
updateMGrammar old new = MGrammar $ 
  [(i,m) | (i,m) <- os, notElem i (map fst ns)] ++ ns
 where
   os = modules old
   ns = modules new

updateModule :: Ord i => Module i f t -> i -> t -> Module i f t
updateModule (Module  mt ms fs me ops js) i t = 
  Module mt ms fs me ops (updateTree (i,t) js)

replaceJudgements :: Module i f t -> BinTree (i,t) -> Module i f t
replaceJudgements (Module mt ms fs me ops _) js = Module mt ms fs me ops js

addOpenQualif :: i -> i -> Module i f t -> Module i f t
addOpenQualif i j (Module mt ms fs me ops js) = 
  Module mt ms fs me (oQualif i j : ops) js

flagsModule :: (i,ModInfo i f a) -> [f]
flagsModule (_,mi) = case mi of
  ModMod m -> flags m
  _ -> []

allFlags :: MGrammar i f a -> [f]
allFlags gr = concat $ map flags $ reverse [m | (_, ModMod m) <- modules gr]

mapModules :: (Module i f a -> Module i f a) 
	   -> MGrammar i f a -> MGrammar i f a 
mapModules f = MGrammar . map (onSnd mapModules') . modules
    where mapModules' (ModMod m) = ModMod (f m)
	  mapModules' m = m

data MainGrammar i = MainGrammar {
    mainAbstract  :: i ,
    mainConcretes :: [MainConcreteSpec i]
  }
  deriving Show

data MainConcreteSpec i = MainConcreteSpec {
    concretePrintname :: i ,
    concreteName :: i ,
    transferIn   :: Maybe (OpenSpec i) ,  -- ^ if there is an in-transfer
    transferOut  :: Maybe (OpenSpec i)    -- ^ if there is an out-transfer
  }
  deriving Show

data OpenSpec i = 
   OSimple OpenQualif i 
 | OQualif OpenQualif i i
  deriving (Eq,Show)

data OpenQualif =
   OQNormal
 | OQInterface
 | OQIncomplete
  deriving (Eq,Show)

oSimple :: i -> OpenSpec i
oSimple = OSimple OQNormal

oQualif :: i -> i -> OpenSpec i
oQualif = OQualif OQNormal

data ModuleStatus = 
   MSComplete 
 | MSIncomplete 
  deriving (Eq,Show)

openedModule :: OpenSpec i -> i
openedModule o = case o of
  OSimple _ m -> m
  OQualif _ _ m -> m

allOpens :: Module i f a -> [OpenSpec i]
allOpens m = case mtype m of
  MTTransfer a b -> a : b : opens m
  _ -> opens m

-- | initial dependency list
depPathModule :: Ord i => Module i f a -> [OpenSpec i]
depPathModule m = fors m ++ exts m ++ opens m where
  fors m = case mtype m of
    MTTransfer i j -> [i,j]
    MTConcrete i   -> [oSimple i]
    MTInstance i   -> [oSimple i]
    _              -> []
  exts m = map oSimple $ extends m

-- | all dependencies
allDepsModule :: Ord i => MGrammar i f a -> Module i f a -> [OpenSpec i]
allDepsModule gr m = iterFix add os0 where
  os0 = depPathModule m
  add os = [m | o <- os, Just (ModMod n) <- [lookup (openedModule o) mods], 
                m <- depPathModule n]
  mods = modules gr

-- | select just those modules that a given one depends on, including itself
partOfGrammar :: Ord i => MGrammar i f a -> (i,ModInfo i f a) -> MGrammar i f a
partOfGrammar gr (i,m) = MGrammar [mo | mo@(j,_) <- mods, elem j modsFor] 
  where
    mods = modules gr
    modsFor = case m of
      ModMod n -> (i:) $ map openedModule $ allDepsModule gr n
      _ -> [i] ---- ModWith?


-- | all modules that a module extends, directly or indirectly
allExtends :: (Show i,Ord i) => MGrammar i f a -> i -> [i]
allExtends gr i = case lookupModule gr i of
  Ok (ModMod m) -> case extends m of 
    [] -> [i]
    is -> i : concatMap (allExtends gr) is
  _ -> []

-- | this plus that an instance extends its interface
allExtendsPlus :: (Show i,Ord i) => MGrammar i f a -> i -> [i]
allExtendsPlus gr i = case lookupModule gr i of
  Ok (ModMod m) -> i : concatMap (allExtendsPlus gr) (exts m)
  _ -> []
 where
   exts m = extends m ++ [j | MTInstance j <- [mtype m]]

-- | conversely: all modules that extend a given module, incl. instances of interface
allExtensions :: (Show i,Ord i) => MGrammar i f a -> i -> [i]
allExtensions gr i = case lookupModule gr i of
  Ok (ModMod m) -> let es = exts i in es ++ concatMap (allExtensions gr) es
  _ -> []
 where
   exts i = [j | (j,m) <- mods, elem i (extends m) 
                             || elem (MTInstance i) [mtype m]]
   mods = [(j,m) | (j,ModMod m) <- modules gr]

-- | initial search path: the nonqualified dependencies
searchPathModule :: Ord i => Module i f a -> [i]
searchPathModule m = [i | OSimple _ i <- depPathModule m]

-- | a new module can safely be added to the end, since nothing old can depend on it
addModule :: Ord i => 
             MGrammar i f a -> i -> ModInfo i f a -> MGrammar i f a
addModule gr name mi = MGrammar $ (modules gr ++ [(name,mi)])

emptyMGrammar :: MGrammar i f a
emptyMGrammar = MGrammar []

emptyModInfo :: ModInfo i f a
emptyModInfo = ModMod emptyModule

emptyModule :: Module i f a
emptyModule = Module MTResource MSComplete [] [] [] NT

-- | we store the module type with the identifier
data IdentM i = IdentM {
  identM :: i ,
  typeM  :: ModuleType i
  }
  deriving (Eq,Show)

typeOfModule :: ModInfo i f a -> ModuleType i
typeOfModule mi = case mi of
  ModMod m -> mtype m

abstractOfConcrete :: (Show i, Eq i) => MGrammar i f a -> i -> Err i
abstractOfConcrete gr c = do
  m <- lookupModule gr c
  case m of
    ModMod n -> case mtype n of
      MTConcrete a -> return a
      _ -> Bad $ "expected concrete" +++ show c
    _ -> Bad $ "expected concrete" +++ show c

abstractModOfConcrete :: (Show i, Eq i) => 
                         MGrammar i f a -> i -> Err (Module i f a)
abstractModOfConcrete gr c = do
  a <- abstractOfConcrete gr c
  m <- lookupModule gr a
  case m of
    ModMod n -> return n
    _ -> Bad $ "expected abstract" +++ show c


-- the canonical file name

--- canonFileName s = prt s ++ ".gfc"

lookupModule :: (Show i,Eq i) => MGrammar i f a -> i -> Err (ModInfo i f a)
lookupModule gr m = case lookup m (modules gr) of
  Just i -> return i
  _ -> Bad $ "unknown module" +++ show m 
             +++ "among" +++ unwords (map (show . fst) (modules gr)) ---- debug

lookupModuleType :: (Show i,Eq i) => MGrammar i f a -> i -> Err (ModuleType i)
lookupModuleType gr m = do
  mi <- lookupModule gr m
  return $ typeOfModule mi

lookupModMod :: (Show i,Eq i) => MGrammar i f a -> i -> Err (Module i f a)
lookupModMod gr i = do
  mo <- lookupModule gr i
  case mo of 
    ModMod m -> return m
    _ -> Bad $ "expected proper module, not" +++ show i

lookupInfo :: (Show i, Ord i) => Module i f a -> i -> Err a
lookupInfo mo i = lookupTree show i (jments mo)

allModMod :: (Show i,Eq i) => MGrammar i f a -> [(i,Module i f a)]
allModMod gr = [(i,m) | (i, ModMod m) <- modules gr]

isModAbs :: Module i f a -> Bool
isModAbs m = case mtype m of
  MTAbstract -> True
----  MTUnion t -> isModAbs t
  _ -> False

isModRes :: Module i f a -> Bool
isModRes m = case mtype m of
  MTResource -> True
  MTReuse _ -> True
----  MTUnion t -> isModRes t --- maybe not needed, since eliminated early
  MTInterface -> True ---
  MTInstance _ -> True
  _ -> False

isModCnc :: Module i f a -> Bool
isModCnc m = case mtype m of
  MTConcrete _ -> True
----  MTUnion t -> isModCnc t
  _ -> False

isModTrans :: Module i f a -> Bool
isModTrans m = case mtype m of
  MTTransfer _ _ -> True
----  MTUnion t -> isModTrans t
  _ -> False

sameMType :: Eq i => ModuleType i -> ModuleType i -> Bool
sameMType m n = case (m,n) of
  (MTConcrete _, MTConcrete _) -> True
  (MTInstance _, MTInstance _) -> True
  (MTInstance _, MTResource) -> True
  (MTInstance _, MTInterface) -> True
  (MTResource, MTInstance _) -> True
  (MTResource, MTInterface) -> True
  (MTInterface,MTResource) -> True
  _ -> m == n

-- | don't generate code for interfaces and for incomplete modules
isCompilableModule :: ModInfo i f a -> Bool
isCompilableModule m = case m of
  ModMod m -> case mtype m of
    MTInterface -> False
    _ -> mstatus m == MSComplete
  _ -> False ---

-- | interface and "incomplete M" are not complete
isCompleteModule :: (Eq i) =>  Module i f a -> Bool
isCompleteModule m = mstatus m == MSComplete && mtype m /= MTInterface


-- | all abstract modules
allAbstracts :: Eq i => MGrammar i f a -> [i]
allAbstracts gr = [i | (i,ModMod m) <- modules gr, mtype m == MTAbstract]

-- | the last abstract in dependency order (head of list)
greatestAbstract :: Eq i => MGrammar i f a -> Maybe i
greatestAbstract gr = case allAbstracts gr of
  []  -> Nothing
  a:_ -> return a

-- | all resource modules
allResources :: MGrammar i f a -> [i]
allResources gr = [i | (i,ModMod m) <- modules gr, isModRes m]

-- | the greatest resource in dependency order
greatestResource :: MGrammar i f a -> Maybe i
greatestResource gr = case allResources gr of
  [] -> Nothing
  a -> return $ head a

-- | all concretes for a given abstract
allConcretes :: Eq i => MGrammar i f a -> i -> [i]
allConcretes gr a = [i | (i, ModMod m) <- modules gr, mtype m == MTConcrete a]