{-# LANGUAGE FlexibleContexts, ScopedTypeVariables #-}

module Opaleye.Sql (
  -- * Showing SQL
  showSql,
  showSqlUnopt,
  -- * Explicit versions
  showSqlExplicit,
  showSqlUnoptExplicit,
  ) where

import qualified Opaleye.Internal.Unpackspec as U
import qualified Opaleye.Internal.Print as Pr
import qualified Opaleye.Internal.Optimize as Op
import           Opaleye.Internal.Helpers ((.:), atSameType)
import qualified Opaleye.Internal.QueryArr as Q

import qualified Opaleye.Select as S

import qualified Data.Profunctor.Product.Default as D

-- | Show the SQL query string generated from the 'S.Select'.
--
-- When 'Nothing' is returned it means that the 'S.Select' returns zero
-- rows.
--
-- Example type specialization:
--
-- @
-- showSql :: Select (Field a, Field b) -> Maybe String
-- @
--
-- Assuming the @makeAdaptorAndInstance@ splice has been run for the
-- product type @Foo@:
--
-- @
-- showSql :: Select (Foo (Field a) (Field b) (Field c)) -> Maybe String
-- @
showSql :: D.Default U.Unpackspec fields fields
        => S.Select fields
        -> Maybe String
showSql :: forall fields.
Default Unpackspec fields fields =>
Select fields -> Maybe String
showSql = forall fields b.
Unpackspec fields b -> Select fields -> Maybe String
showSqlExplicit (forall (p :: * -> * -> *) a. p a a -> p a a
atSameType forall (p :: * -> * -> *) a b. Default p a b => p a b
D.def)

-- | Show the unoptimized SQL query string generated from the 'S.Select'.
showSqlUnopt :: D.Default U.Unpackspec fields fields
             => S.Select fields
             -> Maybe String
showSqlUnopt :: forall fields.
Default Unpackspec fields fields =>
Select fields -> Maybe String
showSqlUnopt = forall fields b.
Unpackspec fields b -> Select fields -> Maybe String
showSqlUnoptExplicit (forall (p :: * -> * -> *) a. p a a -> p a a
atSameType forall (p :: * -> * -> *) a b. Default p a b => p a b
D.def)

showSqlExplicit :: U.Unpackspec fields b -> S.Select fields -> Maybe String
showSqlExplicit :: forall fields b.
Unpackspec fields b -> Select fields -> Maybe String
showSqlExplicit = forall a. ([PrimExpr], PrimQuery' a, Tag) -> Maybe String
Pr.formatAndShowSQL
                  forall b c a. (b -> c) -> (a -> b) -> a -> c
. (\([PrimExpr]
x, PrimQuery' ()
y, Tag
z) -> ([PrimExpr]
x, forall a. PrimQuery' a -> PrimQuery' a
Op.optimize PrimQuery' ()
y, Tag
z))
                  forall r z a b. (r -> z) -> (a -> b -> r) -> a -> b -> z
.: forall a b.
Unpackspec a b -> Query a -> ([PrimExpr], PrimQuery' (), Tag)
Q.runQueryArrUnpack

showSqlUnoptExplicit :: U.Unpackspec fields b -> S.Select fields -> Maybe String
showSqlUnoptExplicit :: forall fields b.
Unpackspec fields b -> Select fields -> Maybe String
showSqlUnoptExplicit = forall a. ([PrimExpr], PrimQuery' a, Tag) -> Maybe String
Pr.formatAndShowSQL forall r z a b. (r -> z) -> (a -> b -> r) -> a -> b -> z
.: forall a b.
Unpackspec a b -> Query a -> ([PrimExpr], PrimQuery' (), Tag)
Q.runQueryArrUnpack