{-# LANGUAGE CPP #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE TupleSections #-}
{-# LANGUAGE UndecidableInstances #-}

module Agda.TypeChecking.Pretty where

import Prelude hiding (null)

import Control.Applicative hiding (empty)
import Data.Maybe

import Agda.Syntax.Position
import Agda.Syntax.Common hiding (Arg, Dom, NamedArg, ArgInfo)
import qualified Agda.Syntax.Common as Common
import Agda.Syntax.Internal
import Agda.Syntax.Literal
import Agda.Syntax.Translation.InternalToAbstract
import Agda.Syntax.Translation.AbstractToConcrete
import qualified Agda.Syntax.Abstract as A
import qualified Agda.Syntax.Concrete as C
import qualified Agda.Syntax.Abstract.Pretty as AP
import qualified Agda.Syntax.Concrete.Pretty as CP

import Agda.TypeChecking.Monad

import Agda.Utils.Maybe
import Agda.Utils.Null
import Agda.Utils.Permutation (Permutation)
import qualified Agda.Utils.Pretty as P

#include "undefined.h"
import Agda.Utils.Impossible

---------------------------------------------------------------------------
-- * Wrappers for pretty printing combinators
---------------------------------------------------------------------------

type Doc = P.Doc

instance Null (TCM Doc) where
  empty = return empty
  null = __IMPOSSIBLE__

comma, colon, equals :: TCM Doc
comma  = return P.comma
colon  = return P.colon
equals = return P.equals

pretty :: P.Pretty a => a -> TCM Doc
pretty x = return $ P.pretty x

prettyA :: (P.Pretty c, ToConcrete a c) => a -> TCM Doc
prettyA x = AP.prettyA x

prettyAs :: (P.Pretty c, ToConcrete a [c]) => a -> TCM Doc
prettyAs x = AP.prettyAs x

text :: String -> TCM Doc
text s = return $ P.text s

pwords :: String -> [TCM Doc]
pwords s = map return $ P.pwords s

fwords :: String -> TCM Doc
fwords s = return $ P.fwords s

sep, fsep, hsep, hcat, vcat :: [TCM Doc] -> TCM Doc
sep ds  = P.sep <$> sequence ds
fsep ds = P.fsep <$> sequence ds
hsep ds = P.hsep <$> sequence ds
hcat ds = P.hcat <$> sequence ds
vcat ds = P.vcat <$> sequence ds

($$), ($+$), (<>), (<+>) :: TCM Doc -> TCM Doc -> TCM Doc
d1 $$ d2  = (P.$$) <$> d1 <*> d2
d1 $+$ d2 = (P.$+$) <$> d1 <*> d2
d1 <> d2  = (P.<>) <$> d1 <*> d2
d1 <+> d2 = (P.<+>) <$> d1 <*> d2

nest :: Int -> TCM Doc -> TCM Doc
nest n d   = P.nest n <$> d

braces, dbraces, brackets, parens :: TCM Doc -> TCM Doc
braces d   = P.braces <$> d
dbraces d  = CP.dbraces <$> d
brackets d = P.brackets <$> d
parens d   = P.parens <$> d

-- | Comma-separated list in brackets.
prettyList :: [TCM Doc] -> TCM Doc
prettyList ds = brackets $ fsep $ punctuate comma ds

-- | 'prettyList' without the brackets.
prettyList_ :: [TCM Doc] -> TCM Doc
prettyList_ ds = fsep $ punctuate comma ds

punctuate :: TCM Doc -> [TCM Doc] -> [TCM Doc]
punctuate _ [] = []
punctuate d ds = zipWith (<>) ds (replicate n d ++ [empty])
  where
    n = length ds - 1

---------------------------------------------------------------------------
-- * The PrettyTCM class
---------------------------------------------------------------------------

class PrettyTCM a where
  prettyTCM :: a -> TCM Doc

instance PrettyTCM Bool        where prettyTCM = pretty
instance PrettyTCM C.Name      where prettyTCM = pretty
instance PrettyTCM C.QName     where prettyTCM = pretty
instance PrettyTCM Comparison  where prettyTCM = pretty
instance PrettyTCM Literal     where prettyTCM = pretty
instance PrettyTCM Nat         where prettyTCM = pretty
instance PrettyTCM ProblemId   where prettyTCM = pretty
instance PrettyTCM Range       where prettyTCM = pretty
-- instance PrettyTCM Interval where prettyTCM = pretty
-- instance PrettyTCM Position where prettyTCM = pretty

instance PrettyTCM a => PrettyTCM (Closure a) where
  prettyTCM cl = enterClosure cl prettyTCM

instance PrettyTCM a => PrettyTCM [a] where
  prettyTCM = prettyList . map prettyTCM

instance (PrettyTCM a, PrettyTCM b) => PrettyTCM (a,b) where
  prettyTCM (a, b) = parens $ prettyTCM a <> comma <> prettyTCM b

instance (PrettyTCM a, PrettyTCM b, PrettyTCM c) => PrettyTCM (a,b,c) where
  prettyTCM (a, b, c) = parens $
    prettyTCM a <> comma <> prettyTCM b <> comma <> prettyTCM c

instance PrettyTCM Term where prettyTCM x = prettyA =<< reify x
instance PrettyTCM Type where prettyTCM x = prettyA =<< reify x
instance PrettyTCM Sort where prettyTCM x = prettyA =<< reify x
instance PrettyTCM DisplayTerm where prettyTCM x = prettyA =<< reify x
instance PrettyTCM NamedClause where prettyTCM x = prettyA =<< reify x
instance PrettyTCM Level where prettyTCM x = prettyA =<< reify (Level x)
instance PrettyTCM Permutation where prettyTCM = text . show

instance PrettyTCM Clause where
  prettyTCM cl = do
    x <- qualify_ <$> freshName_ "<unnamedclause>"
    prettyTCM (QNamed x cl)

instance PrettyTCM ClauseBody where
  prettyTCM b = do
    (binds, body) <- walk b
    sep [ brackets (fsep binds), return body ]
    where
      walk NoBody = return ([], P.text "()")
      walk (Body v) = ([],) <$> prettyTCM v
      walk (Bind b) = do
        (bs, v) <- underAbstraction_ b walk
        return (text (argNameToString $ absName b) : bs, v)

instance PrettyTCM a => PrettyTCM (Judgement a) where
  prettyTCM (HasType a t) = prettyTCM a <+> text ":" <+> prettyTCM t
  prettyTCM (IsSort  a t) = text "Sort" <+> prettyTCM a <+> text ":" <+> prettyTCM t

instance PrettyTCM MetaId where
  prettyTCM x = do
    mn <- getMetaNameSuggestion x
    pretty $ NamedMeta mn x

instance PrettyTCM a => PrettyTCM (Blocked a) where
  prettyTCM (Blocked x a) = text "[" <+> prettyTCM a <+> text "]" <> text (show x)
  prettyTCM (NotBlocked _ x) = prettyTCM x

instance (Reify a e, ToConcrete e c, P.Pretty c) => PrettyTCM (Named_ a) where
  prettyTCM x = prettyA =<< reify x

instance (Reify a e, ToConcrete e c, P.Pretty c) => PrettyTCM (Arg a) where
  prettyTCM x = prettyA =<< reify x

instance (Reify a e, ToConcrete e c, P.Pretty c) => PrettyTCM (Dom a) where
  prettyTCM x = prettyA =<< reify x

-- instance (Reify a e, ToConcrete e c, P.Pretty c, PrettyTCM a) => PrettyTCM (Elim' a) where
instance PrettyTCM Elim where
  prettyTCM (Apply v) = text "$" <+> prettyTCM v
  prettyTCM (Proj f)  = text "." <> prettyTCM f

instance PrettyTCM a => PrettyTCM (MaybeReduced a) where
  prettyTCM = prettyTCM . ignoreReduced

instance PrettyTCM A.Expr where
  prettyTCM = prettyA

instance PrettyTCM Relevance where
  prettyTCM Irrelevant = text "."
  prettyTCM NonStrict  = text ".."
  prettyTCM Relevant   = empty
  prettyTCM Forced{}   = empty
  prettyTCM UnusedArg  = empty

instance PrettyTCM ProblemConstraint where
  prettyTCM (PConstr pid c) = brackets (prettyTCM pid) <+> prettyTCM c

instance PrettyTCM Constraint where
    prettyTCM c = case c of
        ValueCmp cmp ty s t ->
            sep [ sep [ prettyTCM s
                      , prettyTCM cmp <+> prettyTCM t
                      ]
                , nest 2 $ text ":" <+> prettyTCM ty
                ]
        ElimCmp cmps t v us vs ->
          sep [ sep [ prettyTCM us
                    , nest 2 $ text "~~" <+> prettyTCM vs
                    ]
              , text ":" <+> prettyTCM t ]
        LevelCmp cmp a b ->
            sep [ prettyTCM a
                , prettyTCM cmp <+> prettyTCM b
                ]
        TypeCmp cmp a b ->
            sep [ prettyTCM a
                , prettyTCM cmp <+> prettyTCM b
                ]
        TelCmp a b cmp tela telb ->
            sep [ prettyTCM tela
                , prettyTCM cmp <+> prettyTCM telb
                ]
        SortCmp cmp s1 s2 ->
            sep [ prettyTCM s1
                , prettyTCM cmp <+> prettyTCM s2
                ]
        Guarded c pid ->
            sep [ prettyTCM c
                , nest 2 $ brackets $ text "blocked on problem" <+> prettyTCM pid
                ]
        UnBlock m   -> do
            -- BlockedConst t <- mvInstantiation <$> lookupMeta m
            mi <- mvInstantiation <$> lookupMeta m
            case mi of
              BlockedConst t ->
                sep [ pretty m <+> text ":="
                    , nest 2 $ prettyTCM t
                    ]
              PostponedTypeCheckingProblem cl _ -> enterClosure cl $ \p ->
                sep [ pretty m <+> text ":="
                    , nest 2 $ prettyTCM p ]
              Open{}  -> __IMPOSSIBLE__
              OpenIFS{}  -> __IMPOSSIBLE__
              InstS{} -> __IMPOSSIBLE__
              InstV{} -> __IMPOSSIBLE__
        FindInScope m Nothing -> do
            t <- getMetaType m
            sep [ text "Find in scope" <+> pretty m <+> text ":"
                , prettyTCM t
                , text " (no candidate for now)"
                ]
        FindInScope m (Just cands) -> do
            t <- getMetaType m
            sep [ text "Find in scope" <+> pretty m <+> text ":"
                , nest 2 $ prettyTCM t
                , sep $ flip map cands $ \(t,ty) ->
                           prettyTCM t <+> text ": " <+> prettyTCM ty
                ]
        IsEmpty r t ->
            sep [ text "Is empty:", nest 2 $ prettyTCM t ]

instance PrettyTCM TypeCheckingProblem where
  prettyTCM (CheckExpr e a) =
    sep [ prettyA e <+> text ":?", prettyTCM a ]
  prettyTCM (CheckArgs _ _ _ es t0 t1 _) =
    sep [ parens $ text "_ :" <+> prettyTCM t0
        , nest 2 $ prettyList $ map prettyA es
        , nest 2 $ text ":?" <+> prettyTCM t1 ]
  prettyTCM (CheckLambda (Common.Arg ai (xs, mt)) e t) =
    sep [ return CP.lambda <+>
          (CP.prettyRelevance ai .
           CP.prettyHiding ai (if isNothing mt && length xs == 1 then id
                               else P.parens) <$> do
            fsep $
              map prettyTCM xs ++
              caseMaybe mt [] (\ a -> [text ":", prettyTCM a])) <+>
          return CP.arrow <+>
          prettyTCM e <+>
          text ":?"
        , prettyTCM t
        ]

instance PrettyTCM a => PrettyTCM (WithHiding a) where
  prettyTCM (WithHiding h a) = CP.prettyHiding h id <$> prettyTCM a

instance PrettyTCM Name where
  prettyTCM x = P.pretty <$> abstractToConcrete_ x

instance PrettyTCM QName where
  prettyTCM x = P.pretty <$> abstractToConcrete_ x

instance PrettyTCM ModuleName where
  prettyTCM x = P.pretty <$> abstractToConcrete_ x

instance PrettyTCM ConHead where
  prettyTCM = prettyTCM . conName

instance PrettyTCM Telescope where
  prettyTCM tel = P.fsep . map P.pretty <$> (do
      tel <- reify tel
      runAbsToCon $ bindToConcrete tel (return . concat)
    )

newtype PrettyContext = PrettyContext Context

instance PrettyTCM PrettyContext where
  prettyTCM (PrettyContext ctx) = P.fsep . reverse <$> pr (map ctxEntry ctx)
    where
    pr :: [Dom (Name, Type)] -> TCM [P.Doc]
    pr []                            = return []
    pr (Common.Dom info (x,t) : ctx) = escapeContext 1 $ do
      -- TODO guilhem: show colors
      d <- CP.prettyRelevance info . CP.prettyHiding info P.parens <$> do
             prettyTCM x <+> text ":" <+> prettyTCM t
      (d :) <$> pr ctx

instance PrettyTCM Context where
  prettyTCM = prettyTCM . PrettyContext

instance PrettyTCM Pattern where
  prettyTCM = showPat' (text . patVarNameToString)

instance PrettyTCM DeBruijnPattern where
  prettyTCM = showPat' $ \ (i, x) -> text $ patVarNameToString x ++ "@" ++ show i

-- | Show a pattern, given a method how to show pattern variables.
showPat' :: (a -> TCM Doc) -> Pattern' a -> TCM Doc
showPat' showVar = showPat
  where
      showPat (VarP x)      = showVar x
      showPat (DotP t)      = text $ ".(" ++ show t ++ ")"
      showPat (ConP c i ps) = (if b then braces else parens) $ prTy $
        prettyTCM c <+> fsep (map (showPat . namedArg) ps)
        where
        b = fromMaybe False $ conPRecord i
        prTy d = caseMaybe (conPType i) d $ \ t -> d  <+> text ":" <+> prettyTCM t
      showPat (LitP l)      = text (show l)
      showPat (ProjP q)     = text (show q)

instance PrettyTCM (Elim' DisplayTerm) where
  prettyTCM (Apply v) = text "$" <+> prettyTCM (unArg v)
  prettyTCM (Proj f)  = text "." <> prettyTCM f

instance PrettyTCM (Elim' NLPat) where
  prettyTCM (Apply v) = text "$" <+> prettyTCM (unArg v)
  prettyTCM (Proj f)  = text "." <> prettyTCM f

instance PrettyTCM NLPat where
  prettyTCM (PVar x)    = prettyTCM (var x)
  prettyTCM (PWild)     = text $ "_"
  prettyTCM (PDef f es) = parens $
    prettyTCM f <+> fsep (map prettyTCM es)
  prettyTCM (PTerm t)   = text "." <> parens (prettyTCM t)

instance PrettyTCM RewriteRule where
  prettyTCM (RewriteRule q gamma lhs rhs b) = inTopContext $ do
    prettyTCM q <+> text " rule " <+> do
      prettyTCM gamma <+> text " |- " <+> do
        addContext gamma $ do
          prettyTCM lhs <+> text " --> " <+> do
            prettyTCM rhs <+> text " : " <+> do
              prettyTCM b