{-# LANGUAGE GeneralizedNewtypeDeriving #-}

{- |
Copyright : Flipstone Technology Partners 2023
License   : MIT
Stability : Stable

@since 1.0.0.0
-}
module Orville.PostgreSQL.Expr.ReturningExpr
  ( ReturningExpr
  , returningExpr
  )
where

import Orville.PostgreSQL.Expr.Query (SelectList)
import qualified Orville.PostgreSQL.Raw.RawSql as RawSql

{- |
Type to represent a @RETURNING@ clause in a SQL @SELECT@ statement. E.G.

> RETURNING (id)

'ReturningExpr' provides a 'RawSql.SqlExpression' instance. See
'RawSql.unsafeSqlExpression' for how to construct a value with your own custom
SQL.

@since 1.0.0.0
-}
newtype ReturningExpr
  = ReturningExpr RawSql.RawSql
  deriving (RawSql -> ReturningExpr
ReturningExpr -> RawSql
(ReturningExpr -> RawSql)
-> (RawSql -> ReturningExpr) -> SqlExpression ReturningExpr
forall a. (a -> RawSql) -> (RawSql -> a) -> SqlExpression a
$ctoRawSql :: ReturningExpr -> RawSql
toRawSql :: ReturningExpr -> RawSql
$cunsafeFromRawSql :: RawSql -> ReturningExpr
unsafeFromRawSql :: RawSql -> ReturningExpr
RawSql.SqlExpression)

{- |
  Constructs a 'ReturningExpr' that returns the items given in the
  'SelectList'. Essentialy this retults @RETURNING <SelectList items>@.

@since 1.0.0.0
-}
returningExpr :: SelectList -> ReturningExpr
returningExpr :: SelectList -> ReturningExpr
returningExpr SelectList
selectList =
  RawSql -> ReturningExpr
ReturningExpr (RawSql -> ReturningExpr) -> RawSql -> ReturningExpr
forall a b. (a -> b) -> a -> b
$
    String -> RawSql
RawSql.fromString String
"RETURNING "
      RawSql -> RawSql -> RawSql
forall a. Semigroup a => a -> a -> a
<> SelectList -> RawSql
forall a. SqlExpression a => a -> RawSql
RawSql.toRawSql SelectList
selectList