{-# LANGUAGE UndecidableInstances #-}

-- | Define and handle v1/metadata API operations to track, untrack, and get logical models.
module Hasura.NativeQuery.API
  ( GetLogicalModel (..),
    TrackLogicalModel (..),
    UntrackLogicalModel (..),
    runGetLogicalModel,
    runTrackLogicalModel,
    runUntrackLogicalModel,
    dropLogicalModelInMetadata,
    module Hasura.NativeQuery.Types,
  )
where

import Autodocodec (HasCodec)
import Autodocodec qualified as AC
import Control.Lens (preview, (^?))
import Data.Aeson
import Data.Environment qualified as Env
import Data.HashMap.Strict.InsOrd.Extended qualified as OMap
import Hasura.Base.Error
import Hasura.CustomReturnType (CustomReturnType)
import Hasura.EncJSON
import Hasura.Metadata.DTO.Utils (codecNamePrefix)
import Hasura.NativeQuery.Metadata (NativeQueryArgumentName, NativeQueryInfo (..), parseInterpolatedQuery)
import Hasura.NativeQuery.Types
import Hasura.Prelude
import Hasura.RQL.Types.Backend (Backend, ScalarType, SourceConnConfiguration)
import Hasura.RQL.Types.Common (SourceName, sourceNameToText, successMsg)
import Hasura.RQL.Types.Metadata
import Hasura.RQL.Types.Metadata.Backend
import Hasura.RQL.Types.Metadata.Object
import Hasura.RQL.Types.SchemaCache.Build
import Hasura.SQL.AnyBackend qualified as AB
import Hasura.SQL.Backend
import Hasura.Server.Init.FeatureFlag as FF
import Hasura.Server.Types (HasServerConfigCtx (..), ServerConfigCtx (..))
import Language.GraphQL.Draft.Syntax (unName)

-- | Default implementation of the 'track_logical_model' request payload.
data TrackLogicalModel (b :: BackendType) = TrackLogicalModel
  { tnqSource :: SourceName,
    tnqRootFieldName :: LogicalModelName,
    tnqCode :: Text,
    tnqArguments :: HashMap NativeQueryArgumentName (ScalarType b),
    tnqDescription :: Maybe Text,
    tnqReturns :: CustomReturnType b
  }

instance (Backend b) => HasCodec (TrackLogicalModel b) where
  codec =
    AC.CommentCodec
      ("A request to track a logical model")
      $ AC.object (codecNamePrefix @b <> "TrackLogicalModel")
      $ TrackLogicalModel
        <$> AC.requiredField "source" sourceDoc
          AC..= tnqSource
        <*> AC.requiredField "root_field_name" rootFieldDoc
          AC..= tnqRootFieldName
        <*> AC.requiredField "code" codeDoc
          AC..= tnqCode
        <*> AC.optionalFieldWithDefault "arguments" mempty argumentsDoc
          AC..= tnqArguments
        <*> AC.optionalField "description" descriptionDoc
          AC..= tnqDescription
        <*> AC.requiredField "returns" returnsDoc
          AC..= tnqReturns
    where
      sourceDoc = "The source in which this logical model should be tracked"
      rootFieldDoc = "Root field name for the logical model"
      codeDoc = "Native code expression (SQL) to run"
      argumentsDoc = "Free variables in the expression and their types"
      returnsDoc = "Return type (table) of the expression"
      descriptionDoc = "A description of the query which appears in the graphql schema"

deriving via
  (AC.Autodocodec (TrackLogicalModel b))
  instance
    (Backend b) => FromJSON (TrackLogicalModel b)

deriving via
  (AC.Autodocodec (TrackLogicalModel b))
  instance
    (Backend b) => ToJSON (TrackLogicalModel b)

-- | Validate a logical model and extract the logical model info from the request.
logicalModelTrackToInfo ::
  forall b m.
  ( BackendMetadata b,
    MonadIO m,
    MonadError QErr m
  ) =>
  Env.Environment ->
  SourceConnConfiguration b ->
  TrackLogicalModel b ->
  m (NativeQueryInfo b)
logicalModelTrackToInfo env sourceConnConfig TrackLogicalModel {..} = do
  nqiCode <- parseInterpolatedQuery tnqCode `onLeft` \e -> throw400 ParseFailed e
  let nqiRootFieldName = tnqRootFieldName
      nqiReturns = tnqReturns
      nqiArguments = tnqArguments
      nqiDescription = tnqDescription
      nqInfoImpl = NativeQueryInfo {..}

  validateLogicalModel @b env sourceConnConfig nqInfoImpl

  pure nqInfoImpl

-- | API payload for the 'get_logical_model' endpoint.
data GetLogicalModel (b :: BackendType) = GetLogicalModel
  { gnqSource :: SourceName
  }

deriving instance Backend b => Show (GetLogicalModel b)

deriving instance Backend b => Eq (GetLogicalModel b)

instance Backend b => FromJSON (GetLogicalModel b) where
  parseJSON = withObject "GetLogicalModel" $ \o -> do
    gnqSource <- o .: "source"
    pure GetLogicalModel {..}

instance Backend b => ToJSON (GetLogicalModel b) where
  toJSON GetLogicalModel {..} =
    object
      [ "source" .= gnqSource
      ]

-- | Handler for the 'get_logical_model' endpoint.
runGetLogicalModel ::
  forall b m.
  ( BackendMetadata b,
    MetadataM m,
    HasServerConfigCtx m,
    MonadIO m,
    MonadError QErr m
  ) =>
  GetLogicalModel b ->
  m EncJSON
runGetLogicalModel q = do
  throwIfFeatureDisabled

  metadata <- getMetadata

  let logicalModel :: Maybe (NativeQueries b)
      logicalModel = metadata ^? metaSources . ix (gnqSource q) . toSourceMetadata . smNativeQueries @b

  pure (encJFromJValue (OMap.elems <$> logicalModel))

-- | Handler for the 'track_logical_model' endpoint. The type 'TrackLogicalModel b'
-- (appearing here in wrapped as 'BackendTrackLogicalModel b' for 'AnyBackend'
-- compatibility) is defined in 'class LogicalModelMetadata'.
runTrackLogicalModel ::
  forall b m.
  ( BackendMetadata b,
    CacheRWM m,
    MetadataM m,
    MonadError QErr m,
    HasServerConfigCtx m,
    MonadIO m
  ) =>
  Env.Environment ->
  TrackLogicalModel b ->
  m EncJSON
runTrackLogicalModel env trackLogicalModelRequest = do
  throwIfFeatureDisabled

  sourceConnConfig <-
    maybe (throw400 NotFound $ "Source " <> sourceNameToText source <> " not found.") pure
      . preview (metaSources . ix source . toSourceMetadata @b . smConfiguration)
      =<< getMetadata

  (metadata :: NativeQueryInfo b) <- do
    liftIO (runExceptT (logicalModelTrackToInfo @b env sourceConnConfig trackLogicalModelRequest))
      `onLeftM` throwError

  let fieldName = nqiRootFieldName metadata
      metadataObj =
        MOSourceObjId source $
          AB.mkAnyBackend $
            SMOLogicalModel @b fieldName

  buildSchemaCacheFor metadataObj $
    MetadataModifier $
      (metaSources . ix source . toSourceMetadata @b . smNativeQueries)
        %~ OMap.insert fieldName metadata

  pure successMsg
  where
    source = tnqSource trackLogicalModelRequest

-- | API payload for the 'untrack_logical_model' endpoint.
data UntrackLogicalModel (b :: BackendType) = UntrackLogicalModel
  { utnqSource :: SourceName,
    utnqRootFieldName :: LogicalModelName
  }

deriving instance Show (UntrackLogicalModel b)

deriving instance Eq (UntrackLogicalModel b)

instance FromJSON (UntrackLogicalModel b) where
  parseJSON = withObject "UntrackLogicalModel" $ \o -> do
    utnqSource <- o .: "source"
    utnqRootFieldName <- o .: "root_field_name"
    pure UntrackLogicalModel {..}

instance ToJSON (UntrackLogicalModel b) where
  toJSON UntrackLogicalModel {..} =
    object
      [ "source" .= utnqSource,
        "root_field_name" .= utnqRootFieldName
      ]

-- | Handler for the 'untrack_logical_model' endpoint.
runUntrackLogicalModel ::
  forall b m.
  ( BackendMetadata b,
    MonadError QErr m,
    CacheRWM m,
    MetadataM m,
    HasServerConfigCtx m,
    MonadIO m
  ) =>
  UntrackLogicalModel b ->
  m EncJSON
runUntrackLogicalModel q = do
  throwIfFeatureDisabled

  -- Check source exists
  sourceMetadata <-
    maybe (throw400 NotFound $ "Source " <> sourceNameToText source <> " not found.") pure
      . preview (metaSources . ix source . toSourceMetadata @b)
      =<< getMetadata

  -- Check the logical model exists
  unless (any ((== fieldName) . nqiRootFieldName) $ _smNativeQueries sourceMetadata) do
    throw400 NotFound $ "Logical model '" <> unName (getLogicalModelName fieldName) <> "' not found in source '" <> sourceNameToText source <> "'."

  let metadataObj =
        MOSourceObjId source $
          AB.mkAnyBackend $
            SMOLogicalModel @b fieldName

  buildSchemaCacheFor metadataObj $
    dropLogicalModelInMetadata @b source fieldName

  pure successMsg
  where
    source = utnqSource q
    fieldName = utnqRootFieldName q

dropLogicalModelInMetadata :: forall b. BackendMetadata b => SourceName -> LogicalModelName -> MetadataModifier
dropLogicalModelInMetadata source rootFieldName =
  MetadataModifier $
    metaSources . ix source . toSourceMetadata @b . smNativeQueries
      %~ OMap.delete rootFieldName

-- | check feature flag is enabled before carrying out any actions
throwIfFeatureDisabled :: (HasServerConfigCtx m, MonadIO m, MonadError QErr m) => m ()
throwIfFeatureDisabled = do
  configCtx <- askServerConfigCtx

  enableLogicalModels <- liftIO (_sccCheckFeatureFlag configCtx FF.nativeQueryInterface)

  unless enableLogicalModels (throw500 "LogicalModels is disabled!")