content: -- |
  -- Pretty printer for values
  --
  module Language.PureScript.Pretty.Values
    ( prettyPrintValue
    , prettyPrintBinder
    , prettyPrintBinderAtom
    ) where
  
  import Prelude hiding ((<>))
  
  import Control.Arrow (second)
  
  import Data.Text (Text)
  import Data.List.NonEmpty qualified as NEL
  import Data.Monoid qualified as Monoid ((<>))
  import Data.Text qualified as T
  
  import Language.PureScript.AST (AssocList(..), Binder(..), CaseAlternative(..), Declaration(..), DoNotationElement(..), Expr(..), Guard(..), GuardedExpr(..), Literal(..), PathNode(..), PathTree(..), TypeDeclarationData(..), pattern ValueDecl, WhereProvenance(..))
  import Language.PureScript.Crash (internalError)
  import Language.PureScript.Names (OpName(..), ProperName(..), Qualified(..), disqualify, runModuleName, showIdent)
  import Language.PureScript.Pretty.Common (before, beforeWithSpace, parensT)
  import Language.PureScript.Pretty.Types (typeAsBox, typeAtomAsBox, prettyPrintObjectKey)
  import Language.PureScript.Types (Constraint(..))
  import Language.PureScript.PSString (PSString, prettyPrintString)
  
  import Text.PrettyPrint.Boxes (Box, left, moveRight, text, vcat, vsep, (//), (<>))
  
  -- TODO(Christoph): remove T.unpack s
  
  textT :: Text -> Box
  textT = text . T.unpack
  
  -- | Render an aligned list of items separated with commas
  list :: Char -> Char -> (a -> Box) -> [a] -> Box
  list open close _ [] = text [open, close]
  list open close f xs = vcat left (zipWith toLine [0 :: Int ..] xs ++ [ text [ close ] ])
    where
    toLine i a = text [ if i == 0 then open else ',', ' ' ] <> f a
  
  ellipsis :: Box
  ellipsis = text "..."
  
  prettyPrintObject :: Int -> [(PSString, Maybe Expr)] -> Box
  prettyPrintObject d = list '{' '}' prettyPrintObjectProperty
    where
    prettyPrintObjectProperty :: (PSString, Maybe Expr) -> Box
    prettyPrintObjectProperty (key, value) = textT (prettyPrintObjectKey key Monoid.<> ": ") <> maybe (text "_") (prettyPrintValue (d - 1)) value
  
  prettyPrintUpdateEntry :: Int -> PSString -> Expr -> Box
  prettyPrintUpdateEntry d key val = textT (prettyPrintObjectKey key) <> text " = " <> prettyPrintValue (d - 1) val
  
  -- | Pretty-print an expression
  prettyPrintValue :: Int -> Expr -> Box
  prettyPrintValue d _ | d < 0 = text "..."
  prettyPrintValue d (IfThenElse cond th el) =
    (text "if " <> prettyPrintValueAtom (d - 1) cond)
    // moveRight 2 (vcat left [ text "then " <> prettyPrintValueAtom (d - 1) th
                              , text "else " <> prettyPrintValueAtom (d - 1) el
                              ])
  prettyPrintValue d (Accessor prop val) = prettyPrintValueAtom (d - 1) val `before` textT ("." Monoid.<> prettyPrintObjectKey prop)
  prettyPrintValue d (ObjectUpdate o ps) = prettyPrintValueAtom (d - 1) o `beforeWithSpace` list '{' '}' (uncurry (prettyPrintUpdateEntry d)) ps
  prettyPrintValue d (ObjectUpdateNested o ps) = prettyPrintValueAtom (d - 1) o `beforeWithSpace` prettyPrintUpdate ps
    where
      prettyPrintUpdate (PathTree tree) = list '{' '}' printNode (runAssocList tree)
      printNode (key, Leaf val) = prettyPrintUpdateEntry d key val
      printNode (key, Branch val) = textT (prettyPrintObjectKey key) `beforeWithSpace` prettyPrintUpdate val
  prettyPrintValue d (App val arg) = prettyPrintValueAtom (d - 1) val `beforeWithSpace` prettyPrintValueAtom (d - 1) arg
  prettyPrintValue d (VisibleTypeApp val _) = prettyPrintValueAtom (d - 1) val
  prettyPrintValue d (Unused val) = prettyPrintValue d val
  prettyPrintValue d (Abs arg val) = text ('\\' : T.unpack (prettyPrintBinder arg) ++ " -> ") // moveRight 2 (prettyPrintValue (d - 1) val)
  prettyPrintValue d (Case values binders) =
    (text "case " <> foldr beforeWithSpace (text "of") (map (prettyPrintValueAtom (d - 1)) values)) //
      moveRight 2 (vcat left (map (prettyPrintCaseAlternative (d - 1)) binders))
  prettyPrintValue d (Let FromWhere ds val) =
    prettyPrintValue (d - 1) val //
      moveRight 2 (text "where" //
                   vcat left (map (prettyPrintDeclaration (d - 1)) ds))
  prettyPrintValue d (Let FromLet ds val) =
    text "let" //
      moveRight 2 (vcat left (map (prettyPrintDeclaration (d - 1)) ds)) //
      (text "in " <> prettyPrintValue (d - 1) val)
  prettyPrintValue d (Do m els) =
    textT (maybe "" ((Monoid.<> ".") . runModuleName) m) <> text "do " <> vcat left (map (prettyPrintDoNotationElement (d - 1)) els)
  prettyPrintValue d (Ado m els yield) =
    textT (maybe "" ((Monoid.<> ".") . runModuleName) m) <> text "ado " <> vcat left (map (prettyPrintDoNotationElement (d - 1)) els) //
    (text "in " <> prettyPrintValue (d - 1) yield)
  -- TODO: constraint kind args
  prettyPrintValue d (TypeClassDictionary (Constraint _ name _ tys _) _ _) = foldl1 beforeWithSpace $ text ("#dict " ++ T.unpack (runProperName (disqualify name))) : map (typeAtomAsBox d) tys
  prettyPrintValue _ (DeferredDictionary name _) = text $ "#dict " ++ T.unpack (runProperName (disqualify name))
  prettyPrintValue _ (DerivedInstancePlaceholder name _) = text $ "#derived " ++ T.unpack (runProperName (disqualify name))
  prettyPrintValue d (TypedValue _ val _) = prettyPrintValue d val
  prettyPrintValue d (PositionedValue _ _ val) = prettyPrintValue d val
  prettyPrintValue d (Literal _ l) = prettyPrintLiteralValue d l
  prettyPrintValue _ (Hole name) = text "?" <> textT name
  prettyPrintValue d expr@AnonymousArgument{} = prettyPrintValueAtom d expr
  prettyPrintValue d expr@Constructor{} = prettyPrintValueAtom d expr
  prettyPrintValue d expr@Var{} = prettyPrintValueAtom d expr
  prettyPrintValue d expr@Op{} = prettyPrintValueAtom d expr
  prettyPrintValue d expr@BinaryNoParens{} = prettyPrintValueAtom d expr
  prettyPrintValue d expr@Parens{} = prettyPrintValueAtom d expr
  prettyPrintValue d expr@UnaryMinus{} = prettyPrintValueAtom d expr
  
  -- | Pretty-print an atomic expression, adding parentheses if necessary.
  prettyPrintValueAtom :: Int -> Expr -> Box
  prettyPrintValueAtom d (Literal _ l) = prettyPrintLiteralValue d l
  prettyPrintValueAtom _ AnonymousArgument = text "_"
  prettyPrintValueAtom _ (Constructor _ name) = text $ T.unpack $ runProperName (disqualify name)
  prettyPrintValueAtom _ (Var _ ident) = text $ T.unpack $ showIdent (disqualify ident)
  prettyPrintValueAtom d (BinaryNoParens op lhs rhs) =
    prettyPrintValue (d - 1) lhs `beforeWithSpace` printOp op `beforeWithSpace` prettyPrintValue (d - 1) rhs
    where
    printOp (Op _ (Qualified _ name)) = text $ T.unpack $ runOpName name
    printOp expr = text "`" <> prettyPrintValue (d - 1) expr `before` text "`"
  prettyPrintValueAtom d (TypedValue _ val _) = prettyPrintValueAtom d val
  prettyPrintValueAtom d (PositionedValue _ _ val) = prettyPrintValueAtom d val
  prettyPrintValueAtom d (Parens expr) = (text "(" <> prettyPrintValue d expr) `before` text ")"
  prettyPrintValueAtom d (UnaryMinus _ expr) = text "(-" <> prettyPrintValue d expr <> text ")"
  prettyPrintValueAtom d expr = (text "(" <> prettyPrintValue d expr) `before` text ")"
  
  prettyPrintLiteralValue :: Int -> Literal Expr -> Box
  prettyPrintLiteralValue _ (NumericLiteral n) = text $ either show show n
  prettyPrintLiteralValue _ (StringLiteral s) = text $ T.unpack $ prettyPrintString s
  prettyPrintLiteralValue _ (CharLiteral c) = text $ show c
  prettyPrintLiteralValue _ (BooleanLiteral True) = text "true"
  prettyPrintLiteralValue _ (BooleanLiteral False) = text "false"
  prettyPrintLiteralValue d (ArrayLiteral xs) = list '[' ']' (prettyPrintValue (d - 1)) xs
  prettyPrintLiteralValue d (ObjectLiteral ps) = prettyPrintObject (d - 1) $ second Just `map` ps
  
  prettyPrintDeclaration :: Int -> Declaration -> Box
  prettyPrintDeclaration d _ | d < 0 = ellipsis
  prettyPrintDeclaration d (TypeDeclaration td) =
    text (T.unpack (showIdent (tydeclIdent td)) ++ " :: ") <> typeAsBox d (tydeclType td)
  prettyPrintDeclaration d (ValueDecl _ ident _ [] [GuardedExpr [] val]) =
    text (T.unpack (showIdent ident) ++ " = ") <> prettyPrintValue (d - 1) val
  prettyPrintDeclaration d (BindingGroupDeclaration ds) =
    vsep 1 left (NEL.toList (fmap (prettyPrintDeclaration (d - 1) . toDecl) ds))
    where
    toDecl ((sa, nm), t, e) = ValueDecl sa nm t [] [GuardedExpr [] e]
  prettyPrintDeclaration _ _ = internalError "Invalid argument to prettyPrintDeclaration"
  
  prettyPrintCaseAlternative :: Int -> CaseAlternative -> Box
  prettyPrintCaseAlternative d _ | d < 0 = ellipsis
  prettyPrintCaseAlternative d (CaseAlternative binders result) =
    text (T.unpack (T.unwords (map prettyPrintBinderAtom binders))) <> prettyPrintResult result
    where
    prettyPrintResult :: [GuardedExpr] -> Box
    prettyPrintResult [GuardedExpr [] v] = text " -> " <> prettyPrintValue (d - 1) v
    prettyPrintResult gs =
      vcat left (map (prettyPrintGuardedValueSep (text " | ")) gs)
  
    prettyPrintGuardedValueSep :: Box -> GuardedExpr -> Box
    prettyPrintGuardedValueSep _ (GuardedExpr [] val) =
      text " -> " <> prettyPrintValue (d - 1) val
  
    prettyPrintGuardedValueSep sep (GuardedExpr [guard] val) =
      foldl1 before [ sep
                    , prettyPrintGuard guard
                    , prettyPrintGuardedValueSep sep (GuardedExpr [] val)
                    ]
  
    prettyPrintGuardedValueSep sep (GuardedExpr (guard : guards) val) =
      vcat left [ foldl1 before
                  [ sep
                  , prettyPrintGuard guard
                  ]
                , prettyPrintGuardedValueSep (text " , ") (GuardedExpr guards val)
                ]
  
    prettyPrintGuard (ConditionGuard cond) =
      prettyPrintValue (d - 1) cond
    prettyPrintGuard (PatternGuard binder val) =
      foldl1 before
      [ text (T.unpack (prettyPrintBinder binder))
      , text " <- "
      , prettyPrintValue (d - 1) val
      ]
  
  prettyPrintDoNotationElement :: Int -> DoNotationElement -> Box
  prettyPrintDoNotationElement d _ | d < 0 = ellipsis
  prettyPrintDoNotationElement d (DoNotationValue val) =
    prettyPrintValue d val
  prettyPrintDoNotationElement d (DoNotationBind binder val) =
    textT (prettyPrintBinder binder Monoid.<> " <- ") <> prettyPrintValue d val
  prettyPrintDoNotationElement d (DoNotationLet ds) =
    text "let" //
      moveRight 2 (vcat left (map (prettyPrintDeclaration (d - 1)) ds))
  prettyPrintDoNotationElement d (PositionedDoNotationElement _ _ el) = prettyPrintDoNotationElement d el
  
  prettyPrintBinderAtom :: Binder -> Text
  prettyPrintBinderAtom NullBinder = "_"
  prettyPrintBinderAtom (LiteralBinder _ l) = prettyPrintLiteralBinder l
  prettyPrintBinderAtom (VarBinder _ ident) = showIdent ident
  prettyPrintBinderAtom (ConstructorBinder _ ctor []) = runProperName (disqualify ctor)
  prettyPrintBinderAtom b@ConstructorBinder{} = parensT (prettyPrintBinder b)
  prettyPrintBinderAtom (NamedBinder _ ident binder) = showIdent ident Monoid.<> "@" Monoid.<> prettyPrintBinder binder
  prettyPrintBinderAtom (PositionedBinder _ _ binder) = prettyPrintBinderAtom binder
  prettyPrintBinderAtom (TypedBinder _ binder) = prettyPrintBinderAtom binder
  prettyPrintBinderAtom (OpBinder _ op) = runOpName (disqualify op)
  prettyPrintBinderAtom (BinaryNoParensBinder op b1 b2) =
    prettyPrintBinderAtom b1 Monoid.<> " " Monoid.<> prettyPrintBinderAtom op Monoid.<> " " Monoid.<> prettyPrintBinderAtom b2
  prettyPrintBinderAtom (ParensInBinder b) = parensT (prettyPrintBinder b)
  
  prettyPrintLiteralBinder :: Literal Binder -> Text
  prettyPrintLiteralBinder (StringLiteral str) = prettyPrintString str
  prettyPrintLiteralBinder (CharLiteral c) = T.pack (show c)
  prettyPrintLiteralBinder (NumericLiteral num) = either (T.pack . show) (T.pack . show) num
  prettyPrintLiteralBinder (BooleanLiteral True) = "true"
  prettyPrintLiteralBinder (BooleanLiteral False) = "false"
  prettyPrintLiteralBinder (ObjectLiteral bs) =
    "{ "
    Monoid.<> T.intercalate ", " (map prettyPrintObjectPropertyBinder bs)
    Monoid.<> " }"
    where
    prettyPrintObjectPropertyBinder :: (PSString, Binder) -> Text
    prettyPrintObjectPropertyBinder (key, binder) = prettyPrintObjectKey key Monoid.<> ": " Monoid.<> prettyPrintBinder binder
  prettyPrintLiteralBinder (ArrayLiteral bs) =
    "[ "
    Monoid.<> T.intercalate ", " (map prettyPrintBinder bs)
    Monoid.<> " ]"
  
  -- |
  -- Generate a pretty-printed string representing a Binder
  --
  prettyPrintBinder :: Binder -> Text
  prettyPrintBinder (ConstructorBinder _ ctor []) = runProperName (disqualify ctor)
  prettyPrintBinder (ConstructorBinder _ ctor args) = runProperName (disqualify ctor) Monoid.<> " " Monoid.<> T.unwords (map prettyPrintBinderAtom args)
  prettyPrintBinder (PositionedBinder _ _ binder) = prettyPrintBinder binder
  prettyPrintBinder (TypedBinder _ binder) = prettyPrintBinder binder
  prettyPrintBinder b = prettyPrintBinderAtom b
  