module Rel8.Statement.Using
  ( ppFrom
  , ppUsing
  )
where

-- base
import Prelude

-- pretty
import Text.PrettyPrint ( Doc, (<+>), parens, text )

-- rel8
import Rel8.Query ( Query )
import Rel8.Schema.Table ( TableSchema(..), ppTable )
import Rel8.Statement.Select ( Optimized(..), ppPrimSelect )


ppFrom :: Query a -> Maybe (Doc, a)
ppFrom :: forall a. Query a -> Maybe (Doc, a)
ppFrom = forall a. String -> Query a -> Maybe (Doc, a)
ppJoin String
"FROM"


ppUsing :: Query a -> Maybe (Doc, a)
ppUsing :: forall a. Query a -> Maybe (Doc, a)
ppUsing = forall a. String -> Query a -> Maybe (Doc, a)
ppJoin String
"USING"


ppJoin :: String -> Query a -> Maybe (Doc, a)
ppJoin :: forall a. String -> Query a -> Maybe (Doc, a)
ppJoin String
clause Query a
join = do
  Doc
doc <- case Optimized Doc
ofrom of
    Optimized Doc
Empty -> forall a. Maybe a
Nothing
    Optimized Doc
Unit -> forall a. a -> Maybe a
Just forall a. Monoid a => a
mempty
    Optimized Doc
doc -> forall a. a -> Maybe a
Just forall a b. (a -> b) -> a -> b
$ String -> Doc
text String
clause Doc -> Doc -> Doc
<+> Doc -> Doc
parens Doc
doc Doc -> Doc -> Doc
<+> forall a. TableSchema a -> Doc
ppTable TableSchema ()
alias
  forall (f :: * -> *) a. Applicative f => a -> f a
pure (Doc
doc, a
a)
  where
    alias :: TableSchema ()
alias = TableSchema {name :: String
name = String
"T1", schema :: Maybe String
schema = forall a. Maybe a
Nothing, columns :: ()
columns = ()}
    (Optimized Doc
ofrom, a
a) = forall a. Query a -> (Optimized Doc, a)
ppPrimSelect Query a
join