module Hasura.RQL.DDL.Relationship.Rename
  ( RenameRel
  , runRenameRel
  ) where

import           Hasura.Prelude

import qualified Data.HashMap.Strict   as Map

import           Data.Aeson
import           Data.Text.Extended

import           Hasura.Base.Error
import           Hasura.EncJSON
import           Hasura.RQL.DDL.Schema (renameRelationshipInMetadata)
import           Hasura.RQL.Types


data RenameRel b
  = RenameRel
  { _rrSource  :: !SourceName
  , _rrTable   :: !(TableName b)
  , _rrName    :: !RelName
  , _rrNewName :: !RelName
  }

instance (Backend b) => FromJSON (RenameRel b) where
  parseJSON = withObject "rename relationship" $ \o ->
    RenameRel
      <$> o .:? "source" .!= defaultSource
      <*> o .: "table"
      <*> o .: "name"
      <*> o .: "new_name"

renameRelP2
  :: forall b m
   . (QErrM m, CacheRM m, BackendMetadata b)
  => SourceName -> TableName b -> RelName -> RelInfo b -> m MetadataModifier
renameRelP2 source qt newRN relInfo = withNewInconsistentObjsCheck $ do
  tabInfo <- askTableCoreInfo @b source qt
  -- check for conflicts in fieldInfoMap
  case Map.lookup (fromRel newRN) $ _tciFieldInfoMap tabInfo of
    Nothing -> return ()
    Just _  ->
      throw400 AlreadyExists $ "cannot rename relationship " <> oldRN
      <<> " to " <> newRN <<> " in table " <> qt <<>
      " as a column/relationship with the name already exists"
  -- update metadata
  execWriterT $ renameRelationshipInMetadata @b source qt oldRN (riType relInfo) newRN
  where
    oldRN = riName relInfo

runRenameRel
  :: forall b m
   . (MonadError QErr m, CacheRWM m, MetadataM m, BackendMetadata b)
  => RenameRel b -> m EncJSON
runRenameRel (RenameRel source qt rn newRN) = do
  tabInfo <- askTableCoreInfo @b source qt
  ri <- askRelType (_tciFieldInfoMap tabInfo) rn ""
  withNewInconsistentObjsCheck $
    renameRelP2 source qt newRN ri >>= buildSchemaCache
  pure successMsg