{-# OPTIONS_GHC -fno-warn-orphans #-}

module Hasura.Backends.DataConnector.Adapter.Execute
  (
  )
where

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import Data.Aeson qualified as J
import Data.ByteString.Lazy qualified as BL
import Data.Environment qualified as Env
import Data.Text.Encoding qualified as TE
import Data.Text.Extended (toTxt)
import Hasura.Backends.DataConnector.API qualified as API
import Hasura.Backends.DataConnector.Adapter.ConfigTransform (transformSourceConfig)
import Hasura.Backends.DataConnector.Adapter.Types (SourceConfig (..))
import Hasura.Backends.DataConnector.Agent.Client (AgentClientT)
import Hasura.Backends.DataConnector.IR.Query qualified as IR.Q
import Hasura.Backends.DataConnector.Plan qualified as DC
import Hasura.Base.Error (Code (..), QErr, throw400, throw500)
import Hasura.EncJSON (EncJSON, encJFromBuilder, encJFromJValue)
import Hasura.GraphQL.Execute.Backend (BackendExecute (..), DBStepInfo (..), ExplainPlan (..))
import Hasura.GraphQL.Namespace qualified as GQL
import Hasura.Prelude
import Hasura.RQL.Types.Common qualified as RQL
import Hasura.SQL.AnyBackend (mkAnyBackend)
import Hasura.SQL.Backend (BackendType (DataConnector))
import Hasura.Session
import Hasura.Tracing (MonadTrace)
import Hasura.Tracing qualified as Tracing
import Servant.Client.Core.HasClient ((//))
import Servant.Client.Generic (genericClient)
import Witch qualified

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instance BackendExecute 'DataConnector where
  type PreparedQuery 'DataConnector = IR.Q.QueryRequest
  type MultiplexedQuery 'DataConnector = Void
  type ExecutionMonad 'DataConnector = AgentClientT (Tracing.TraceT (ExceptT QErr IO))

  mkDBQueryPlan UserInfo {..} env sourceName sourceConfig ir = do
    queryPlan@DC.QueryPlan {..} <- DC.mkPlan _uiSession sourceConfig ir
    transformedSourceConfig <- transformSourceConfig sourceConfig [("$session", J.toJSON _uiSession), ("$env", J.toJSON env)] env
    pure
      DBStepInfo
        { dbsiSourceName = sourceName,
          dbsiSourceConfig = transformedSourceConfig,
          dbsiPreparedQuery = Just _qpRequest,
          dbsiAction = buildAction sourceName transformedSourceConfig queryPlan
        }

  mkDBQueryExplain fieldName UserInfo {..} sourceName sourceConfig ir = do
    DC.QueryPlan {..} <- DC.mkPlan _uiSession sourceConfig ir
    transformedSourceConfig <- transformSourceConfig sourceConfig [("$session", J.toJSON _uiSession), ("$env", J.object [])] Env.emptyEnvironment
    pure $
      mkAnyBackend @'DataConnector
        DBStepInfo
          { dbsiSourceName = sourceName,
            dbsiSourceConfig = transformedSourceConfig,
            dbsiPreparedQuery = Just _qpRequest,
            dbsiAction = pure . encJFromJValue . toExplainPlan fieldName $ _qpRequest
          }
  mkDBMutationPlan _ _ _ _ _ =
    throw400 NotSupported "mkDBMutationPlan: not implemented for the Data Connector backend."
  mkLiveQuerySubscriptionPlan _ _ _ _ _ =
    throw400 NotSupported "mkLiveQuerySubscriptionPlan: not implemented for the Data Connector backend."
  mkDBStreamingSubscriptionPlan _ _ _ _ =
    throw400 NotSupported "mkLiveQuerySubscriptionPlan: not implemented for the Data Connector backend."
  mkDBRemoteRelationshipPlan _ _ _ _ _ _ _ =
    throw500 "mkDBRemoteRelationshipPlan: not implemented for the Data Connector backend."
  mkSubscriptionExplain _ =
    throw400 NotSupported "mkSubscriptionExplain: not implemented for the Data Connector backend."

toExplainPlan :: GQL.RootFieldAlias -> IR.Q.QueryRequest -> ExplainPlan
toExplainPlan fieldName queryRequest =
  ExplainPlan fieldName (Just "") (Just [TE.decodeUtf8 $ BL.toStrict $ J.encode $ queryRequest])

buildAction :: (MonadIO m, MonadTrace m, MonadError QErr m) => RQL.SourceName -> SourceConfig -> DC.QueryPlan -> AgentClientT m EncJSON
buildAction sourceName SourceConfig {..} DC.QueryPlan {..} = do
  -- NOTE: Should this check occur during query construction in 'mkPlan'?
  when (DC.queryHasRelations _qpRequest && isNothing (API.cRelationships _scCapabilities)) $
    throw400 NotSupported "Agents must provide their own dataloader."
  let apiQueryRequest = Witch.into @API.QueryRequest _qpRequest
  queryResponse <- (genericClient // API._query) (toTxt sourceName) _scConfig apiQueryRequest
  reshapedResponse <- _qpResponseReshaper queryResponse
  pure . encJFromBuilder $ J.fromEncoding reshapedResponse