module Hasura.GraphQL.Execute.Mutation
  ( convertMutationSelectionSet
  ) where

import           Hasura.Prelude

import qualified Data.Environment                       as Env
import qualified Data.HashMap.Strict                    as Map
import qualified Data.HashMap.Strict.InsOrd             as OMap
import qualified Data.Sequence.NonEmpty                 as NE
import qualified Language.GraphQL.Draft.Syntax          as G
import qualified Network.HTTP.Client                    as HTTP
import qualified Network.HTTP.Types                     as HTTP

import qualified Hasura.GraphQL.Transport.HTTP.Protocol as GH
import qualified Hasura.Logging                         as L
import qualified Hasura.SQL.AnyBackend                  as AB
import qualified Hasura.Tracing                         as Tracing

import           Hasura.GraphQL.Context
import           Hasura.GraphQL.Execute.Action
import           Hasura.GraphQL.Execute.Backend
import           Hasura.GraphQL.Execute.Common
import           Hasura.GraphQL.Execute.Instances       ()
import           Hasura.GraphQL.Execute.Remote
import           Hasura.GraphQL.Execute.Resolve
import           Hasura.GraphQL.Parser
import           Hasura.Metadata.Class
import           Hasura.RQL.Types
import           Hasura.Server.Version                  (HasVersion)
import           Hasura.Session


convertMutationAction
  ::( HasVersion
    , MonadIO m
    , MonadError QErr m
    , MonadMetadataStorage (MetadataStorageT m)
    )
  => Env.Environment
  -> L.Logger L.Hasura
  -> UserInfo
  -> HTTP.Manager
  -> HTTP.RequestHeaders
  -> ActionMutation ('Postgres 'Vanilla) (UnpreparedValue ('Postgres 'Vanilla))
  -> m ActionExecutionPlan
convertMutationAction env logger userInfo manager reqHeaders  = \case
  AMSync s  -> pure $ AEPSync $ resolveActionExecution env logger userInfo s actionExecContext
  AMAsync s -> AEPAsyncMutation <$>
    liftEitherM (runMetadataStorageT $ resolveActionMutationAsync s reqHeaders userSession)
  where
    userSession = _uiSession userInfo
    actionExecContext = ActionExecContext manager reqHeaders $ _uiSession userInfo

convertMutationSelectionSet
  :: forall m
   . ( HasVersion
     , Tracing.MonadTrace m
     , MonadIO m
     , MonadError QErr m
     , MonadMetadataStorage (MetadataStorageT m)
     , MonadGQLExecutionCheck m
     )
  => Env.Environment
  -> L.Logger L.Hasura
  -> GQLContext
  -> SQLGenCtx
  -> UserInfo
  -> HTTP.Manager
  -> HTTP.RequestHeaders
  -> G.SelectionSet G.NoFragments G.Name
  -> [G.VariableDefinition]
  -> Maybe GH.VariableValues
  -> SetGraphqlIntrospectionOptions
  -> m (ExecutionPlan, G.SelectionSet G.NoFragments Variable)
convertMutationSelectionSet env logger gqlContext SQLGenCtx{stringifyNum} userInfo manager reqHeaders fields varDefs varValsM introspectionDisabledRoles = do
  mutationParser <- onNothing (gqlMutationParser gqlContext) $
    throw400 ValidationFailed "no mutations exist"

  resolvedSelSet <- resolveVariables varDefs (fromMaybe Map.empty varValsM) fields
  -- Parse the GraphQL query into the RQL AST
  (unpreparedQueries, _reusability)
    :: (OMap.InsOrdHashMap G.Name (MutationRootField UnpreparedValue), QueryReusability)
    <-(mutationParser >>> (`onLeft` reportParseErrors)) resolvedSelSet

  -- Transform the RQL AST into a prepared SQL query
  txs <- for unpreparedQueries \case
    RFDB sourceName exists ->
      AB.dispatchAnyBackend @BackendExecute exists
        \(SourceConfigWith sourceConfig (MDBR db)) ->
           mkDBMutationPlan env manager reqHeaders userInfo stringifyNum sourceName sourceConfig db
    RFRemote remoteField -> do
      RemoteFieldG remoteSchemaInfo resolvedRemoteField <- resolveRemoteField userInfo remoteField
      pure $ buildExecStepRemote remoteSchemaInfo G.OperationTypeMutation $ [G.SelectionField resolvedRemoteField]
    RFAction action -> do
      (actionName, _fch) <- pure $ case action of
        AMSync s  -> (_aaeName s, _aaeForwardClientHeaders s)
        AMAsync s -> (_aamaName s, _aamaForwardClientHeaders s)
      plan <- convertMutationAction env logger userInfo manager reqHeaders action
      pure $ ExecStepAction (plan, ActionsInfo actionName _fch) -- `_fch` represents the `forward_client_headers` option from the action
                                                                -- definition which is currently being ignored for actions that are mutations
    RFRaw s -> flip onLeft throwError =<< executeIntrospection userInfo s introspectionDisabledRoles
  return (txs, resolvedSelSet)
  where
    reportParseErrors errs = case NE.head errs of
      -- TODO: Our error reporting machinery doesn’t currently support reporting
      -- multiple errors at once, so we’re throwing away all but the first one
      -- here. It would be nice to report all of them!
      ParseError{ pePath, peMessage, peCode } ->
        throwError (err400 peCode peMessage){ qePath = pePath }