module Hasql.CursorTransaction.Private.Statements
where

import Hasql.CursorTransaction.Private.Prelude
import Hasql.Statement
import qualified Hasql.Encoders as B
import qualified Hasql.Decoders as C
import qualified Hasql.CursorTransaction.Private.Specs as F
import qualified ByteString.TreeBuilder as D


declareCursor :: ByteString -> ByteString -> B.Params a -> Statement a ()
declareCursor name sql encoder =
  Statement sql' encoder C.unit False
  where
    sql' =
      D.toByteString $
      "DECLARE " <> D.byteString name <> " NO SCROLL CURSOR FOR " <> D.byteString sql

closeCursor :: ByteString -> Statement () ()
closeCursor name =
  Statement sql B.unit C.unit True
  where
    sql =
      "CLOSE " <> name

fetchFromCursor :: ByteString -> F.BatchSize -> C.Result result -> Statement () result
fetchFromCursor name (F.BatchSize batchSize) decoder =
  Statement sql encoder decoder True
  where
    sql =
      D.toByteString $
      "FETCH FORWARD " <> D.asciiIntegral batchSize <> " FROM " <> D.byteString name
    encoder =
      B.unit