{-# LANGUAGE CPP #-}
module GhcDump.Convert where

import Data.Bifunctor
import qualified Data.Text as T
import qualified Data.Text.Encoding as TE

import Literal (Literal(..))
#if MIN_VERSION_ghc(8,6,0)
import qualified Literal
#endif
import Var (Var)
import qualified Var
import Id (isFCallId)
import Module (ModuleName, moduleNameFS, moduleName)
import Unique (Unique, getUnique, unpkUnique)
import Name (getOccName, occNameFS, OccName, getName, nameModule_maybe)
import qualified IdInfo
import qualified BasicTypes as OccInfo (OccInfo(..), isStrongLoopBreaker)
#if MIN_VERSION_ghc(8,0,0)
import qualified CoreStats
#else
import qualified CoreUtils as CoreStats
#endif
import qualified CoreSyn
import CoreSyn (Expr(..), CoreExpr, Bind(..), CoreAlt, CoreBind, AltCon(..))
import HscTypes (ModGuts(..))
import FastString (FastString)
import qualified FastString
#if MIN_VERSION_ghc(8,2,0)
import TyCoRep as Type (Type(..))
#elif MIN_VERSION_ghc(8,0,0)
import TyCoRep as Type (Type(..), TyBinder(..))
#else
import TypeRep as Type (Type(..))
#endif
#if !(MIN_VERSION_ghc(8,2,0))
import Type (splitFunTy_maybe)
#endif
import TyCon (TyCon, tyConUnique)

import Outputable (ppr, showSDoc, SDoc)
import DynFlags (unsafeGlobalDynFlags)

import GhcDump.Ast as Ast

cvtSDoc :: SDoc -> T.Text
cvtSDoc = T.pack . showSDoc unsafeGlobalDynFlags

fastStringToText :: FastString -> T.Text
fastStringToText = TE.decodeUtf8
#if MIN_VERSION_ghc(8,10,0)
  . FastString.bytesFS
#else
  . FastString.fastStringToByteString
#endif

occNameToText :: OccName -> T.Text
occNameToText = fastStringToText . occNameFS

cvtUnique :: Unique.Unique -> Ast.Unique
cvtUnique u =
    let (a,b) = unpkUnique u
    in Ast.Unique a b

cvtVar :: Var -> BinderId
cvtVar = BinderId . cvtUnique . Var.varUnique

cvtBinder :: Var -> SBinder
cvtBinder v
  | Var.isId v =
    SBndr $ Binder { binderName   = occNameToText $ getOccName v
                   , binderId     = cvtVar v
                   , binderIdInfo = cvtIdInfo $ Var.idInfo v
                   , binderIdDetails = cvtIdDetails $ Var.idDetails v
                   , binderType   = cvtType $ Var.varType v
                   }
  | otherwise =
    SBndr $ TyBinder { binderName   = occNameToText $ getOccName v
                     , binderId     = cvtVar v
                     , binderKind   = cvtType $ Var.varType v
                     }

cvtIdInfo :: IdInfo.IdInfo -> Ast.IdInfo SBinder BinderId
cvtIdInfo i =
    IdInfo { idiArity         = IdInfo.arityInfo i
           , idiIsOneShot     = IdInfo.oneShotInfo i == IdInfo.OneShotLam
           , idiUnfolding     = cvtUnfolding $ IdInfo.unfoldingInfo i
           , idiInlinePragma  = cvtSDoc $ ppr $ IdInfo.inlinePragInfo i
           , idiOccInfo       = case IdInfo.occInfo i of
#if MIN_VERSION_ghc(8,2,0)
                                  OccInfo.ManyOccs{} -> OccManyOccs
#else
                                  OccInfo.NoOccInfo  -> OccManyOccs
#endif
                                  OccInfo.IAmDead    -> OccDead
                                  OccInfo.OneOcc{}   -> OccOneOcc
                                  oi@OccInfo.IAmALoopBreaker{} -> OccLoopBreaker (OccInfo.isStrongLoopBreaker oi)
           , idiStrictnessSig = cvtSDoc $ ppr $ IdInfo.strictnessInfo i
           , idiDemandSig     = cvtSDoc $ ppr $ IdInfo.demandInfo i
           , idiCallArity     = IdInfo.callArityInfo i
           }

cvtUnfolding :: CoreSyn.Unfolding -> Ast.Unfolding SBinder BinderId
cvtUnfolding CoreSyn.NoUnfolding = Ast.NoUnfolding
#if MIN_VERSION_ghc(8,2,0)
cvtUnfolding CoreSyn.BootUnfolding = Ast.BootUnfolding
#endif
cvtUnfolding (CoreSyn.OtherCon cons) = Ast.OtherCon (map cvtAltCon cons)
cvtUnfolding (CoreSyn.DFunUnfolding{}) = Ast.DFunUnfolding
cvtUnfolding u@(CoreSyn.CoreUnfolding{}) =
    Ast.CoreUnfolding { unfTemplate   = cvtExpr $ CoreSyn.uf_tmpl u
                      , unfIsValue    = CoreSyn.uf_is_value u
                      , unfIsConLike  = CoreSyn.uf_is_conlike u
                      , unfIsWorkFree = CoreSyn.uf_is_work_free u
                      , unfGuidance   = cvtSDoc $ ppr $ CoreSyn.uf_guidance u
                      }

cvtIdDetails :: IdInfo.IdDetails -> Ast.IdDetails
cvtIdDetails d =
    case d of
      IdInfo.VanillaId -> Ast.VanillaId
      IdInfo.RecSelId{} -> Ast.RecSelId
      IdInfo.DataConWorkId{} -> Ast.DataConWorkId
      IdInfo.DataConWrapId{} -> Ast.DataConWrapId
      IdInfo.ClassOpId{} -> Ast.ClassOpId
      IdInfo.PrimOpId{} -> Ast.PrimOpId
      IdInfo.FCallId{} -> error "This shouldn't happen"
      IdInfo.TickBoxOpId{} -> Ast.TickBoxOpId
      IdInfo.DFunId{} -> Ast.DFunId
#if MIN_VERSION_ghc(8,0,0)
      IdInfo.CoVarId{} -> Ast.CoVarId
#endif
#if MIN_VERSION_ghc(8,2,0)
      IdInfo.JoinId n -> Ast.JoinId n
#endif

cvtCoreStats :: CoreStats.CoreStats -> Ast.CoreStats
cvtCoreStats stats =
    Ast.CoreStats
      { csTerms     = CoreStats.cs_tm stats
      , csTypes     = CoreStats.cs_ty stats
      , csCoercions = CoreStats.cs_co stats
#if MIN_VERSION_ghc(8,2,0)
      , csValBinds  = CoreStats.cs_vb stats
      , csJoinBinds = CoreStats.cs_jb stats
#else
      , csValBinds  = 0
      , csJoinBinds = 0
#endif
      }

exprStats :: CoreExpr -> CoreStats.CoreStats
#if MIN_VERSION_ghc(8,0,0)
exprStats = CoreStats.exprStats
#else
-- exprStats wasn't exported in 7.10
exprStats _ = CoreStats.CS 0 0 0
#endif

cvtTopBind :: CoreBind -> STopBinding
cvtTopBind (NonRec b e) =
    NonRecTopBinding (cvtBinder b) (cvtCoreStats $ exprStats e) (cvtExpr e)
cvtTopBind (Rec bs) =
    RecTopBinding $ map to bs
  where to (b, e) = (cvtBinder b, cvtCoreStats $ exprStats e, cvtExpr e)

cvtExpr :: CoreExpr -> Ast.SExpr
cvtExpr expr =
  case expr of
    Var x
        -- foreign calls are local but have no binding site.
        -- TODO: use hasNoBinding here.
      | isFCallId x   -> EVarGlobal ForeignCall
      | Just m <- nameModule_maybe $ getName x
                      -> EVarGlobal $ ExternalName (cvtModuleName $ Module.moduleName m)
                                                   (occNameToText $ getOccName x)
                                                   (cvtUnique $ getUnique x)
      | otherwise     -> EVar (cvtVar x)
    Lit l             -> ELit (cvtLit l)
    App x y           -> EApp (cvtExpr x) (cvtExpr y)
    Lam x e
      | Var.isTyVar x -> ETyLam (cvtBinder x) (cvtExpr e)
      | otherwise     -> ELam (cvtBinder x) (cvtExpr e)
    Let (NonRec b e) body -> ELet [(cvtBinder b, cvtExpr e)] (cvtExpr body)
    Let (Rec bs) body -> ELet (map (bimap cvtBinder cvtExpr) bs) (cvtExpr body)
    Case e x _ as     -> ECase (cvtExpr e) (cvtBinder x) (map cvtAlt as)
    Cast x _          -> cvtExpr x
    Tick _ e          -> cvtExpr e
    Type t            -> EType $ cvtType t
    Coercion _        -> ECoercion

cvtAlt :: CoreAlt -> Ast.SAlt
cvtAlt (con, bs, e) = Alt (cvtAltCon con) (map cvtBinder bs) (cvtExpr e)

cvtAltCon :: CoreSyn.AltCon -> Ast.AltCon
cvtAltCon (DataAlt altcon) = Ast.AltDataCon $ occNameToText $ getOccName altcon
cvtAltCon (LitAlt l)       = Ast.AltLit $ cvtLit l
cvtAltCon DEFAULT          = Ast.AltDefault

cvtLit :: Literal -> Ast.Lit
cvtLit l =
    case l of
#if MIN_VERSION_ghc(8,8,0)
      Literal.LitChar x -> Ast.MachChar x
      Literal.LitString x -> Ast.MachStr x
      Literal.LitNullAddr -> Ast.MachNullAddr
      Literal.LitFloat x -> Ast.MachFloat x
      Literal.LitDouble x -> Ast.MachDouble x
      Literal.LitLabel x _ _ -> Ast.MachLabel $ fastStringToText  x
      Literal.LitRubbish -> Ast.LitRubbish
#else
      Literal.MachChar x -> Ast.MachChar x
      Literal.MachStr x -> Ast.MachStr x
      Literal.MachNullAddr -> Ast.MachNullAddr
      Literal.MachFloat x -> Ast.MachFloat x
      Literal.MachDouble x -> Ast.MachDouble x
      Literal.MachLabel x _ _ -> Ast.MachLabel $ fastStringToText  x
#endif
#if MIN_VERSION_ghc(8,6,0)
      Literal.LitNumber numty n _ ->
        case numty of
          Literal.LitNumInt -> Ast.MachInt n
          Literal.LitNumInt64 -> Ast.MachInt64 n
          Literal.LitNumWord -> Ast.MachWord n
          Literal.LitNumWord64 -> Ast.MachWord64 n
          Literal.LitNumInteger -> Ast.LitInteger n
          Literal.LitNumNatural -> Ast.LitNatural n
#else
      Literal.MachInt x -> Ast.MachInt x
      Literal.MachInt64 x -> Ast.MachInt64 x
      Literal.MachWord x -> Ast.MachWord x
      Literal.MachWord64 x -> Ast.MachWord64 x
      Literal.LitInteger x _ -> Ast.LitInteger x
#endif

cvtModule :: String -> ModGuts -> Ast.SModule
cvtModule phase guts =
    Ast.Module name (T.pack phase) (map cvtTopBind $ mg_binds guts)
  where name = cvtModuleName $ Module.moduleName $ mg_module guts

cvtModuleName :: Module.ModuleName -> Ast.ModuleName
cvtModuleName = Ast.ModuleName . fastStringToText . moduleNameFS

cvtType :: Type.Type -> Ast.SType
#if MIN_VERSION_ghc(8,10,0)
cvtType (Type.FunTy _flag a b) = Ast.FunTy (cvtType a) (cvtType b)
#elif MIN_VERSION_ghc(8,2,0)
cvtType (Type.FunTy a b) = Ast.FunTy (cvtType a) (cvtType b)
#else
cvtType t
  | Just (a,b) <- splitFunTy_maybe t = Ast.FunTy (cvtType a) (cvtType b)
#endif
cvtType (Type.TyVarTy v)       = Ast.VarTy (cvtVar v)
cvtType (Type.AppTy a b)       = Ast.AppTy (cvtType a) (cvtType b)
cvtType (Type.TyConApp tc tys) = Ast.TyConApp (cvtTyCon tc) (map cvtType tys)
#if MIN_VERSION_ghc(8,8,0)
cvtType (Type.ForAllTy (Var.Bndr b _) t) = Ast.ForAllTy (cvtBinder b) (cvtType t)
#elif MIN_VERSION_ghc(8,2,0)
cvtType (Type.ForAllTy (Var.TvBndr b _) t) = Ast.ForAllTy (cvtBinder b) (cvtType t)
#elif MIN_VERSION_ghc(8,0,0)
cvtType (Type.ForAllTy (Named b _) t) = Ast.ForAllTy (cvtBinder b) (cvtType t)
cvtType (Type.ForAllTy (Anon _) t)    = cvtType t
#else
cvtType (Type.ForAllTy b t)    = Ast.ForAllTy (cvtBinder b) (cvtType t)
#endif
cvtType (Type.LitTy _)         = Ast.LitTy
#if MIN_VERSION_ghc(8,0,0)
cvtType (Type.CastTy t _)      = cvtType t
cvtType (Type.CoercionTy _)    = Ast.CoercionTy
#endif

cvtTyCon :: TyCon.TyCon -> Ast.TyCon
cvtTyCon tc = TyCon (occNameToText $ getOccName tc) (cvtUnique $ tyConUnique tc)