{-# OPTIONS_GHC -Wno-orphans      #-} -- Outputable and IEWrappedName
{-# LANGUAGE DataKinds            #-}
{-# LANGUAGE StandaloneDeriving   #-}
{-# LANGUAGE DeriveDataTypeable   #-}
{-# LANGUAGE FlexibleContexts     #-}
{-# LANGUAGE FlexibleInstances    #-}
{-# LANGUAGE TypeApplications     #-}
{-# LANGUAGE TypeFamilies         #-}
{-# LANGUAGE UndecidableInstances #-} -- Wrinkle in Note [Trees That Grow]
                                      -- in module Language.Haskell.Syntax.Extension
{-
(c) The University of Glasgow 2006
(c) The GRASP/AQUA Project, Glasgow University, 1992-1998


GHC.Hs.ImpExp: Abstract syntax: imports, exports, interfaces
-}

module GHC.Hs.ImpExp
    ( module Language.Haskell.Syntax.ImpExp
    , module GHC.Hs.ImpExp
    ) where

import GHC.Prelude

import GHC.Types.SourceText   ( SourceText(..) )
import GHC.Types.FieldLabel   ( FieldLabel )

import GHC.Utils.Outputable
import GHC.Utils.Panic
import GHC.Types.SrcLoc
import GHC.Parser.Annotation
import GHC.Hs.Extension
import GHC.Types.Name
import GHC.Types.PkgQual

import Data.Data
import Data.Maybe

import Language.Haskell.Syntax.Extension
import Language.Haskell.Syntax.Module.Name
import Language.Haskell.Syntax.ImpExp

{-
************************************************************************
*                                                                      *
    Import and export declaration lists
*                                                                      *
************************************************************************

One per import declaration in a module.
-}

type instance Anno (ImportDecl (GhcPass p)) = SrcSpanAnnA

-- | Given two possible located 'qualified' tokens, compute a style
-- (in a conforming Haskell program only one of the two can be not
-- 'Nothing'). This is called from "GHC.Parser".
importDeclQualifiedStyle :: Maybe EpaLocation
                         -> Maybe EpaLocation
                         -> (Maybe EpaLocation, ImportDeclQualifiedStyle)
importDeclQualifiedStyle mPre mPost =
  if isJust mPre then (mPre, QualifiedPre)
  else if isJust mPost then (mPost,QualifiedPost) else (Nothing, NotQualified)

-- | Convenience function to answer the question if an import decl. is
-- qualified.
isImportDeclQualified :: ImportDeclQualifiedStyle -> Bool
isImportDeclQualified NotQualified = False
isImportDeclQualified _ = True


type instance ImportDeclPkgQual GhcPs = RawPkgQual
type instance ImportDeclPkgQual GhcRn = PkgQual
type instance ImportDeclPkgQual GhcTc = PkgQual

type instance XCImportDecl  GhcPs = XImportDeclPass
type instance XCImportDecl  GhcRn = XImportDeclPass
type instance XCImportDecl  GhcTc = DataConCantHappen
                                 -- Note [Pragma source text] in GHC.Types.SourceText

data XImportDeclPass = XImportDeclPass
    { ideclAnn        :: EpAnn EpAnnImportDecl
    , ideclSourceText :: SourceText
    , ideclImplicit   :: Bool
        -- ^ GHC generates an `ImportDecl` to represent the invisible `import Prelude`
        -- that appears in any file that omits `import Prelude`, setting
        -- this field to indicate that the import doesn't appear in the
        -- original source. True => implicit import (of Prelude)
    }
    deriving (Data)

type instance XXImportDecl  (GhcPass _) = DataConCantHappen

type instance Anno ModuleName = SrcSpanAnnA
type instance Anno [LocatedA (IE (GhcPass p))] = SrcSpanAnnL

deriving instance Data (IEWrappedName GhcPs)
deriving instance Data (IEWrappedName GhcRn)
deriving instance Data (IEWrappedName GhcTc)

deriving instance Eq (IEWrappedName GhcPs)
deriving instance Eq (IEWrappedName GhcRn)
deriving instance Eq (IEWrappedName GhcTc)

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

-- API Annotations types

data EpAnnImportDecl = EpAnnImportDecl
  { importDeclAnnImport    :: EpaLocation
  , importDeclAnnPragma    :: Maybe (EpaLocation, EpaLocation)
  , importDeclAnnSafe      :: Maybe EpaLocation
  , importDeclAnnQualified :: Maybe EpaLocation
  , importDeclAnnPackage   :: Maybe EpaLocation
  , importDeclAnnAs        :: Maybe EpaLocation
  } deriving (Data)

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

simpleImportDecl :: ModuleName -> ImportDecl GhcPs
simpleImportDecl mn = ImportDecl {
      ideclExt        = XImportDeclPass noAnn NoSourceText False,
      ideclName       = noLocA mn,
      ideclPkgQual    = NoRawPkgQual,
      ideclSource     = NotBoot,
      ideclSafe       = False,
      ideclQualified  = NotQualified,
      ideclAs         = Nothing,
      ideclImportList = Nothing
    }

instance (OutputableBndrId p
         , Outputable (Anno (IE (GhcPass p)))
         , Outputable (ImportDeclPkgQual (GhcPass p)))
       => Outputable (ImportDecl (GhcPass p)) where
    ppr (ImportDecl { ideclExt = impExt, ideclName = mod'
                    , ideclPkgQual = pkg
                    , ideclSource = from, ideclSafe = safe
                    , ideclQualified = qual
                    , ideclAs = as, ideclImportList = spec })
      = hang (hsep [text "import", ppr_imp impExt from, pp_implicit impExt, pp_safe safe,
                    pp_qual qual False, ppr pkg, ppr mod', pp_qual qual True, pp_as as])
             4 (pp_spec spec)
      where
        pp_implicit ext =
            let implicit = case ghcPass @p of
                            GhcPs | XImportDeclPass { ideclImplicit = implicit } <- ext -> implicit
                            GhcRn | XImportDeclPass { ideclImplicit = implicit } <- ext -> implicit
                            GhcTc -> dataConCantHappen ext
            in if implicit then text "(implicit)"
                           else empty

        pp_qual QualifiedPre False = text "qualified" -- Prepositive qualifier/prepositive position.
        pp_qual QualifiedPost True = text "qualified" -- Postpositive qualifier/postpositive position.
        pp_qual QualifiedPre True = empty -- Prepositive qualifier/postpositive position.
        pp_qual QualifiedPost False = empty -- Postpositive qualifier/prepositive position.
        pp_qual NotQualified _ = empty

        pp_safe False   = empty
        pp_safe True    = text "safe"

        pp_as Nothing   = empty
        pp_as (Just a)  = text "as" <+> ppr a

        ppr_imp ext IsBoot =
            let mSrcText = case ghcPass @p of
                                GhcPs | XImportDeclPass { ideclSourceText = mst } <- ext -> mst
                                GhcRn | XImportDeclPass { ideclSourceText = mst } <- ext -> mst
                                GhcTc -> dataConCantHappen ext
            in case mSrcText of
                  NoSourceText   -> text "{-# SOURCE #-}"
                  SourceText src -> text src <+> text "#-}"
        ppr_imp _ NotBoot = empty

        pp_spec Nothing             = empty
        pp_spec (Just (Exactly, (L _ ies))) = ppr_ies ies
        pp_spec (Just (EverythingBut, (L _ ies))) = text "hiding" <+> ppr_ies ies

        ppr_ies []  = text "()"
        ppr_ies ies = char '(' <+> interpp'SP ies <+> char ')'

{-
************************************************************************
*                                                                      *
\subsection{Imported and exported entities}
*                                                                      *
************************************************************************
-}

type instance XIEName    (GhcPass _) = NoExtField
type instance XIEPattern (GhcPass _) = EpaLocation
type instance XIEType    (GhcPass _) = EpaLocation
type instance XXIEWrappedName (GhcPass _) = DataConCantHappen

type instance Anno (IEWrappedName (GhcPass _)) = SrcSpanAnnA

type instance Anno (IE (GhcPass p)) = SrcSpanAnnA

type instance XIEVar             GhcPs = NoExtField
type instance XIEVar             GhcRn = NoExtField
type instance XIEVar             GhcTc = NoExtField

type instance XIEThingAbs        (GhcPass _) = EpAnn [AddEpAnn]
type instance XIEThingAll        (GhcPass _) = EpAnn [AddEpAnn]

-- See Note [IEThingWith]
type instance XIEThingWith       (GhcPass 'Parsed)      = EpAnn [AddEpAnn]
type instance XIEThingWith       (GhcPass 'Renamed)     = [Located FieldLabel]
type instance XIEThingWith       (GhcPass 'Typechecked) = NoExtField

type instance XIEModuleContents  GhcPs = EpAnn [AddEpAnn]
type instance XIEModuleContents  GhcRn = NoExtField
type instance XIEModuleContents  GhcTc = NoExtField

type instance XIEGroup           (GhcPass _) = NoExtField
type instance XIEDoc             (GhcPass _) = NoExtField
type instance XIEDocNamed        (GhcPass _) = NoExtField
type instance XXIE               (GhcPass _) = DataConCantHappen

type instance Anno (LocatedA (IE (GhcPass p))) = SrcSpanAnnA

{-
Note [IEThingWith]
~~~~~~~~~~~~~~~~~~
A definition like

    {-# LANGUAGE DuplicateRecordFields #-}
    module M ( T(MkT, x) ) where
      data T = MkT { x :: Int }

gives rise to this in the output of the parser:

    IEThingWith NoExtField T [MkT, x] NoIEWildcard

But in the renamer we need to attach the correct field label,
because the selector Name is mangled (see Note [FieldLabel] in
GHC.Types.FieldLabel).  Hence we change this to:

    IEThingWith [FieldLabel "x" True $sel:x:MkT)] T [MkT] NoIEWildcard

using the TTG extension field to store the list of fields in renamed syntax
only.  (Record fields always appear in this list, regardless of whether
DuplicateRecordFields was in use at the definition site or not.)

See Note [Representing fields in AvailInfo] in GHC.Types.Avail for more details.
-}

ieName :: IE (GhcPass p) -> IdP (GhcPass p)
ieName (IEVar _ (L _ n))            = ieWrappedName n
ieName (IEThingAbs  _ (L _ n))      = ieWrappedName n
ieName (IEThingWith _ (L _ n) _ _)  = ieWrappedName n
ieName (IEThingAll  _ (L _ n))      = ieWrappedName n
ieName _ = panic "ieName failed pattern match!"

ieNames :: IE (GhcPass p) -> [IdP (GhcPass p)]
ieNames (IEVar       _ (L _ n)   )   = [ieWrappedName n]
ieNames (IEThingAbs  _ (L _ n)   )   = [ieWrappedName n]
ieNames (IEThingAll  _ (L _ n)   )   = [ieWrappedName n]
ieNames (IEThingWith _ (L _ n) _ ns) = ieWrappedName n
                                     : map (ieWrappedName . unLoc) ns
-- NB the above case does not include names of field selectors
ieNames (IEModuleContents {})     = []
ieNames (IEGroup          {})     = []
ieNames (IEDoc            {})     = []
ieNames (IEDocNamed       {})     = []

ieWrappedLName :: IEWrappedName (GhcPass p) -> LIdP (GhcPass p)
ieWrappedLName (IEName    _ (L l n)) = L l n
ieWrappedLName (IEPattern _ (L l n)) = L l n
ieWrappedLName (IEType    _ (L l n)) = L l n

ieWrappedName :: IEWrappedName (GhcPass p) -> IdP (GhcPass p)
ieWrappedName = unLoc . ieWrappedLName


lieWrappedName :: LIEWrappedName (GhcPass p) -> IdP (GhcPass p)
lieWrappedName (L _ n) = ieWrappedName n

ieLWrappedName :: LIEWrappedName (GhcPass p) -> LIdP (GhcPass p)
ieLWrappedName (L _ n) = ieWrappedLName n

replaceWrappedName :: IEWrappedName GhcPs -> IdP GhcRn -> IEWrappedName GhcRn
replaceWrappedName (IEName    x (L l _)) n = IEName    x (L l n)
replaceWrappedName (IEPattern r (L l _)) n = IEPattern r (L l n)
replaceWrappedName (IEType    r (L l _)) n = IEType    r (L l n)

replaceLWrappedName :: LIEWrappedName GhcPs -> IdP GhcRn -> LIEWrappedName GhcRn
replaceLWrappedName (L l n) n' = L l (replaceWrappedName n n')

instance OutputableBndrId p => Outputable (IE (GhcPass p)) where
    ppr (IEVar       _     var) = ppr (unLoc var)
    ppr (IEThingAbs  _   thing) = ppr (unLoc thing)
    ppr (IEThingAll  _   thing) = hcat [ppr (unLoc thing), text "(..)"]
    ppr (IEThingWith flds thing wc withs)
        = ppr (unLoc thing) <> parens (fsep (punctuate comma
                                              (ppWiths ++ ppFields) ))
      where
        ppWiths =
          case wc of
              NoIEWildcard ->
                map (ppr . unLoc) withs
              IEWildcard pos ->
                let (bs, as) = splitAt pos (map (ppr . unLoc) withs)
                in bs ++ [text ".."] ++ as
        ppFields =
          case ghcPass @p of
            GhcRn -> map ppr flds
            _     -> []
    ppr (IEModuleContents _ mod')
        = text "module" <+> ppr mod'
    ppr (IEGroup _ n _)           = text ("<IEGroup: " ++ show n ++ ">")
    ppr (IEDoc _ doc)             = ppr doc
    ppr (IEDocNamed _ string)     = text ("<IEDocNamed: " ++ string ++ ">")

instance (HasOccName (IdP (GhcPass p)), OutputableBndrId p) => HasOccName (IEWrappedName (GhcPass p)) where
  occName w = occName (ieWrappedName w)

instance OutputableBndrId p => OutputableBndr (IEWrappedName (GhcPass p)) where
  pprBndr bs   w = pprBndr bs   (ieWrappedName w)
  pprPrefixOcc w = pprPrefixOcc (ieWrappedName w)
  pprInfixOcc  w = pprInfixOcc  (ieWrappedName w)

instance OutputableBndrId p => Outputable (IEWrappedName (GhcPass p)) where
  ppr (IEName    _ (L _ n)) = pprPrefixOcc n
  ppr (IEPattern _ (L _ n)) = text "pattern" <+> pprPrefixOcc n
  ppr (IEType    _ (L _ n)) = text "type"    <+> pprPrefixOcc n

pprImpExp :: (HasOccName name, OutputableBndr name) => name -> SDoc
pprImpExp name = type_pref <+> pprPrefixOcc name
    where
    occ = occName name
    type_pref | isTcOcc occ && isSymOcc occ = text "type"
              | otherwise                   = empty