Array.hs

module Hasql.Encoders.Array where

import qualified Hasql.PTI as B
import Hasql.Prelude
import qualified PostgreSQL.Binary.Encoding as A
import qualified Text.Builder as C

data Array a
  = Array B.OID B.OID (Bool -> a -> A.Array) (a -> C.Builder)

instance Contravariant Array where
  contramap fn (Array valueOid arrayOid encoder renderer) =
    Array valueOid arrayOid (\intDateTimes -> encoder intDateTimes . fn) (renderer . fn)

{-# INLINE value #-}
value :: B.OID -> B.OID -> (Bool -> a -> A.Encoding) -> (a -> C.Builder) -> Array a
value valueOID arrayOID encoder =
  Array valueOID arrayOID (\params -> A.encodingArray . encoder params)

{-# INLINE nullableValue #-}
nullableValue :: B.OID -> B.OID -> (Bool -> a -> A.Encoding) -> (a -> C.Builder) -> Array (Maybe a)
nullableValue valueOID arrayOID encoder renderer =
  let maybeEncoder params =
        maybe A.nullArray (A.encodingArray . encoder params)
      maybeRenderer =
        maybe (C.string "null") renderer
   in Array valueOID arrayOID maybeEncoder maybeRenderer

{-# INLINE dimension #-}
dimension :: (forall a. (a -> b -> a) -> a -> c -> a) -> Array b -> Array c
dimension fold (Array valueOID arrayOID elEncoder elRenderer) =
  let encoder el =
        A.dimensionArray fold (elEncoder el)
      renderer els =
        let folded =
              let step builder el =
                    if C.null builder
                      then C.char '[' <> elRenderer el
                      else builder <> C.string ", " <> elRenderer el
               in fold step mempty els
         in if C.null folded
              then C.string "[]"
              else folded <> C.char ']'
   in Array valueOID arrayOID encoder renderer