{-# LANGUAGE RecordWildCards #-}
module Hasura.RQL.DDL.Action
  ( CreateAction
  , runCreateAction
  , persistCreateAction
  , resolveAction

  , UpdateAction
  , runUpdateAction

  , DropAction
  , runDropAction
  , deleteActionFromCatalog

  , fetchActions

  , CreateActionPermission
  , runCreateActionPermission
  , persistCreateActionPermission

  , DropActionPermission
  , runDropActionPermission
  , deleteActionPermissionFromCatalog
  ) where

import           Hasura.EncJSON
import           Hasura.GraphQL.Context        (defaultTypes)
import           Hasura.GraphQL.Utils
import           Hasura.Prelude
import           Hasura.RQL.Types
import           Hasura.SQL.Types

import qualified Hasura.GraphQL.Validate.Types as VT

import qualified Data.Aeson                    as J
import qualified Data.Aeson.Casing             as J
import qualified Data.Aeson.TH                 as J
import qualified Data.HashMap.Strict           as Map
import qualified Data.Text                     as T
import qualified Database.PG.Query             as Q
import qualified Language.GraphQL.Draft.Syntax as G

import           Data.URL.Template             (renderURLTemplate)
import           Language.Haskell.TH.Syntax    (Lift)

getActionInfo
  :: (QErrM m, CacheRM m)
  => ActionName -> m ActionInfo
getActionInfo actionName = do
  actionMap <- scActions <$> askSchemaCache
  case Map.lookup actionName actionMap of
    Just actionInfo -> return actionInfo
    Nothing         ->
      throw400 NotExists $
      "action with name " <> actionName <<> " does not exist"

runCreateAction
  :: (QErrM m , CacheRWM m, MonadTx m)
  => CreateAction -> m EncJSON
runCreateAction createAction = do
  -- check if action with same name exists already
  actionMap <- scActions <$> askSchemaCache
  void $ onJust (Map.lookup actionName actionMap) $ const $
    throw400 AlreadyExists $
      "action with name " <> actionName <<> " already exists"
  persistCreateAction createAction
  buildSchemaCacheFor $ MOAction actionName
  pure successMsg
  where
    actionName = _caName createAction

persistCreateAction :: (MonadTx m) =>  CreateAction -> m ()
persistCreateAction (CreateAction actionName actionDefinition comment) = do
  liftTx $ Q.unitQE defaultTxErrorHandler [Q.sql|
    INSERT into hdb_catalog.hdb_action
      (action_name, action_defn, comment)
      VALUES ($1, $2, $3)
  |] (actionName, Q.AltJ actionDefinition, comment) True

resolveAction
  :: (QErrM m, MonadIO m)
  => (NonObjectTypeMap, AnnotatedObjects)
  -> ActionDefinitionInput
  -> m (ResolvedActionDefinition, ActionOutputFields)
resolveAction customTypes actionDefinition = do
  let responseType = unGraphQLType $ _adOutputType actionDefinition
      responseBaseType = G.getBaseType responseType
  forM (_adArguments actionDefinition) $ \argument -> do
    let argumentBaseType = G.getBaseType $ unGraphQLType $ _argType argument
    argTypeInfo <- getNonObjectTypeInfo argumentBaseType
    case argTypeInfo of
      VT.TIScalar _ -> return ()
      VT.TIEnum _   -> return ()
      VT.TIInpObj _ -> return ()
      _ -> throw400 InvalidParams $ "the argument's base type: "
          <> showNamedTy argumentBaseType <>
          " should be a scalar/enum/input_object"
  -- Check if the response type is an object
  annFields <- _aotAnnotatedFields <$> getObjectTypeInfo responseBaseType
  let outputFields = Map.fromList $ map (unObjectFieldName *** fst) $ Map.toList annFields
  resolvedDef <- traverse resolveWebhook actionDefinition
  pure (resolvedDef, outputFields)
  where
    getNonObjectTypeInfo typeName = do
      let nonObjectTypeMap = unNonObjectTypeMap $ fst $ customTypes
          inputTypeInfos = nonObjectTypeMap <> mapFromL VT.getNamedTy defaultTypes
      onNothing (Map.lookup typeName inputTypeInfos) $
        throw400 NotExists $ "the type: " <> showNamedTy typeName <>
        " is not defined in custom types"

    resolveWebhook (InputWebhook urlTemplate) = do
      eitherRenderedTemplate <- renderURLTemplate urlTemplate
      either (throw400 Unexpected . T.pack) (pure . ResolvedWebhook) eitherRenderedTemplate

    getObjectTypeInfo typeName =
      onNothing (Map.lookup (ObjectTypeName typeName) (snd customTypes)) $
        throw400 NotExists $ "the type: "
        <> showNamedTy typeName <>
        " is not an object type defined in custom types"

runUpdateAction
  :: forall m. ( QErrM m , CacheRWM m, MonadTx m)
  => UpdateAction -> m EncJSON
runUpdateAction (UpdateAction actionName actionDefinition) = do
  sc <- askSchemaCache
  let actionsMap = scActions sc
  void $ onNothing (Map.lookup actionName actionsMap) $
    throw400 NotExists $ "action with name " <> actionName <<> " not exists"
  updateActionInCatalog
  buildSchemaCacheFor $ MOAction actionName
  pure successMsg
  where
    updateActionInCatalog :: m ()
    updateActionInCatalog =
      liftTx $ Q.unitQE defaultTxErrorHandler [Q.sql|
        UPDATE hdb_catalog.hdb_action
           SET action_defn = $2
         WHERE action_name = $1
      |] (actionName, Q.AltJ actionDefinition) True

newtype ClearActionData
  = ClearActionData { unClearActionData :: Bool }
  deriving (Show, Eq, Lift, J.FromJSON, J.ToJSON)

shouldClearActionData :: ClearActionData -> Bool
shouldClearActionData = unClearActionData

defaultClearActionData :: ClearActionData
defaultClearActionData = ClearActionData True

data DropAction
  = DropAction
  { _daName      :: !ActionName
  , _daClearData :: !(Maybe ClearActionData)
  } deriving (Show, Eq, Lift)
$(J.deriveJSON (J.aesonDrop 3 J.snakeCase) ''DropAction)

runDropAction
  :: (QErrM m, CacheRWM m, MonadTx m)
  => DropAction -> m EncJSON
runDropAction (DropAction actionName clearDataM)= do
  void $ getActionInfo actionName
  liftTx $ do
    deleteActionPermissionsFromCatalog
    deleteActionFromCatalog actionName clearDataM
  buildSchemaCacheStrict
  return successMsg
  where
    deleteActionPermissionsFromCatalog =
      Q.unitQE defaultTxErrorHandler [Q.sql|
          DELETE FROM hdb_catalog.hdb_action_permission
            WHERE action_name = $1
          |] (Identity actionName) True

deleteActionFromCatalog
  :: ActionName
  -> Maybe ClearActionData
  -> Q.TxE QErr ()
deleteActionFromCatalog actionName clearDataM = do
  Q.unitQE defaultTxErrorHandler [Q.sql|
      DELETE FROM hdb_catalog.hdb_action
        WHERE action_name = $1
      |] (Identity actionName) True
  when (shouldClearActionData clearData) $
    clearActionDataFromCatalog actionName
  where
    -- When clearData is not present we assume that
    -- the data needs to be retained
    clearData = fromMaybe defaultClearActionData clearDataM

clearActionDataFromCatalog :: ActionName -> Q.TxE QErr ()
clearActionDataFromCatalog actionName =
  Q.unitQE defaultTxErrorHandler [Q.sql|
      DELETE FROM hdb_catalog.hdb_action_log
        WHERE action_name = $1
      |] (Identity actionName) True

fetchActions :: Q.TxE QErr [CreateAction]
fetchActions =
  map fromRow <$> Q.listQE defaultTxErrorHandler
    [Q.sql|
     SELECT action_name, action_defn, comment
       FROM hdb_catalog.hdb_action
       ORDER BY action_name ASC
     |] () True
  where
    fromRow (actionName, Q.AltJ definition, comment) =
      CreateAction actionName definition comment

newtype ActionMetadataField
  = ActionMetadataField { unActionMetadataField :: Text }
  deriving (Show, Eq, J.FromJSON, J.ToJSON)

runCreateActionPermission
  :: (QErrM m , CacheRWM m, MonadTx m)
  => CreateActionPermission -> m EncJSON
runCreateActionPermission createActionPermission = do
  actionInfo <- getActionInfo actionName
  void $ onJust (Map.lookup role $ _aiPermissions actionInfo) $ const $
    throw400 AlreadyExists $ "permission for role: " <> role
    <<> "is already defined on " <>> actionName
  persistCreateActionPermission createActionPermission
  buildSchemaCacheFor $ MOActionPermission actionName role
  pure successMsg
  where
    actionName = _capAction createActionPermission
    role = _capRole createActionPermission

persistCreateActionPermission :: (MonadTx m) => CreateActionPermission -> m ()
persistCreateActionPermission CreateActionPermission{..}= do
  liftTx $ Q.unitQE defaultTxErrorHandler [Q.sql|
    INSERT into hdb_catalog.hdb_action_permission
      (action_name, role_name, comment)
      VALUES ($1, $2, $3)
  |] (_capAction, _capRole, _capComment) True

data DropActionPermission
  = DropActionPermission
  { _dapAction :: !ActionName
  , _dapRole   :: !RoleName
  } deriving (Show, Eq, Lift)
$(J.deriveJSON (J.aesonDrop 4 J.snakeCase) ''DropActionPermission)

runDropActionPermission
  :: (QErrM m, CacheRWM m, MonadTx m)
  => DropActionPermission -> m EncJSON
runDropActionPermission dropActionPermission = do
  actionInfo <- getActionInfo actionName
  void $ onNothing (Map.lookup role $ _aiPermissions actionInfo) $
    throw400 NotExists $
    "permission for role: " <> role <<> " is not defined on " <>> actionName
  liftTx $ deleteActionPermissionFromCatalog actionName role
  return successMsg
  where
    actionName = _dapAction dropActionPermission
    role = _dapRole dropActionPermission

deleteActionPermissionFromCatalog :: ActionName -> RoleName -> Q.TxE QErr ()
deleteActionPermissionFromCatalog actionName role =
  Q.unitQE defaultTxErrorHandler [Q.sql|
      DELETE FROM hdb_catalog.hdb_action_permission
        WHERE action_name = $1
          AND role_name = $2
      |] (actionName, role) True