module Hasura.RQL.DDL.ScheduledTrigger
  ( runCreateCronTrigger,
    runDeleteCronTrigger,
    dropCronTriggerInMetadata,
    resolveCronTrigger,
    runCreateScheduledEvent,
    runDeleteScheduledEvent,
    runGetScheduledEvents,
    runGetEventInvocations,
    populateInitialCronTriggerEvents,
  )
where

import Data.Aeson qualified as J
import Data.Environment qualified as Env
import Data.HashMap.Strict qualified as Map
import Data.HashMap.Strict.InsOrd qualified as OMap
import Data.Time.Clock qualified as C
import Hasura.Base.Error
import Hasura.EncJSON
import Hasura.Eventing.ScheduledTrigger
import Hasura.Metadata.Class
import Hasura.Prelude
import Hasura.RQL.DDL.EventTrigger (getHeaderInfosFromConf)
import Hasura.RQL.Types
import System.Cron.Types (CronSchedule)

populateInitialCronTriggerEvents ::
  ( MonadIO m,
    MonadMetadataStorageQueryAPI m
  ) =>
  CronSchedule ->
  TriggerName ->
  m ()
populateInitialCronTriggerEvents schedule triggerName = do
  currentTime <- liftIO C.getCurrentTime
  let scheduleTimes = generateScheduleTimes currentTime 100 schedule
  insertCronEvents $ map (CronEventSeed triggerName) scheduleTimes
  pure ()

-- | runCreateCronTrigger will update a existing cron trigger when the 'replace'
--   value is set to @true@ and when replace is @false@ a new cron trigger will
--   be created
runCreateCronTrigger ::
  ( CacheRWM m,
    MonadIO m,
    MetadataM m,
    MonadMetadataStorageQueryAPI m
  ) =>
  CreateCronTrigger ->
  m EncJSON
runCreateCronTrigger CreateCronTrigger {..} = do
  let q =
        CronTriggerMetadata
          cctName
          cctWebhook
          cctCronSchedule
          cctPayload
          cctRetryConf
          cctHeaders
          cctIncludeInMetadata
          cctComment
  case cctReplace of
    True -> updateCronTrigger q
    False -> do
      cronTriggersMap <- scCronTriggers <$> askSchemaCache
      case Map.lookup (ctName q) cronTriggersMap of
        Nothing -> pure ()
        Just _ ->
          throw400 AlreadyExists $
            "cron trigger with name: "
              <> triggerNameToTxt (ctName q)
              <> " already exists"

      let metadataObj = MOCronTrigger cctName
          metadata =
            CronTriggerMetadata
              cctName
              cctWebhook
              cctCronSchedule
              cctPayload
              cctRetryConf
              cctHeaders
              cctIncludeInMetadata
              cctComment
      buildSchemaCacheFor metadataObj $
        MetadataModifier $
          metaCronTriggers %~ OMap.insert cctName metadata
      populateInitialCronTriggerEvents cctCronSchedule cctName
      return successMsg

resolveCronTrigger ::
  (QErrM m) =>
  Env.Environment ->
  CronTriggerMetadata ->
  m CronTriggerInfo
resolveCronTrigger env CronTriggerMetadata {..} = do
  webhookInfo <- resolveWebhook env ctWebhook
  headerInfo <- getHeaderInfosFromConf env ctHeaders
  pure $
    CronTriggerInfo
      ctName
      ctSchedule
      ctPayload
      ctRetryConf
      webhookInfo
      headerInfo
      ctComment

updateCronTrigger ::
  ( CacheRWM m,
    MonadIO m,
    MetadataM m,
    MonadMetadataStorageQueryAPI m
  ) =>
  CronTriggerMetadata ->
  m EncJSON
updateCronTrigger cronTriggerMetadata = do
  let triggerName = ctName cronTriggerMetadata
  checkExists triggerName
  buildSchemaCacheFor (MOCronTrigger triggerName) $
    MetadataModifier $
      metaCronTriggers %~ OMap.insert triggerName cronTriggerMetadata
  dropFutureCronEvents $ SingleCronTrigger triggerName
  currentTime <- liftIO C.getCurrentTime
  let scheduleTimes = generateScheduleTimes currentTime 100 $ ctSchedule cronTriggerMetadata
  insertCronEvents $ map (CronEventSeed triggerName) scheduleTimes
  pure successMsg

runDeleteCronTrigger ::
  ( CacheRWM m,
    MetadataM m,
    MonadMetadataStorageQueryAPI m
  ) =>
  ScheduledTriggerName ->
  m EncJSON
runDeleteCronTrigger (ScheduledTriggerName stName) = do
  checkExists stName
  withNewInconsistentObjsCheck $
    buildSchemaCache $
      dropCronTriggerInMetadata stName
  dropFutureCronEvents $ SingleCronTrigger stName
  return successMsg

dropCronTriggerInMetadata :: TriggerName -> MetadataModifier
dropCronTriggerInMetadata name =
  MetadataModifier $ metaCronTriggers %~ OMap.delete name

runCreateScheduledEvent ::
  (MonadMetadataStorageQueryAPI m) =>
  CreateScheduledEvent ->
  m EncJSON
runCreateScheduledEvent scheduledEvent = do
  eid <- createOneOffScheduledEvent scheduledEvent
  pure $ encJFromJValue $ J.object ["message" J..= J.String "success", "event_id" J..= eid]

checkExists :: (CacheRM m, MonadError QErr m) => TriggerName -> m ()
checkExists name = do
  cronTriggersMap <- scCronTriggers <$> askSchemaCache
  void $
    onNothing (Map.lookup name cronTriggersMap) $
      throw400 NotExists $
        "cron trigger with name: " <> triggerNameToTxt name <> " does not exist"

runDeleteScheduledEvent ::
  (MonadMetadataStorageQueryAPI m) => DeleteScheduledEvent -> m EncJSON
runDeleteScheduledEvent DeleteScheduledEvent {..} = do
  dropEvent _dseEventId _dseType
  pure successMsg

runGetScheduledEvents ::
  ( CacheRM m,
    MonadMetadataStorageQueryAPI m
  ) =>
  GetScheduledEvents ->
  m EncJSON
runGetScheduledEvents gse = do
  case _gseScheduledEvent gse of
    SEOneOff -> pure ()
    SECron name -> checkExists name
  encJFromJValue <$> fetchScheduledEvents gse

runGetEventInvocations ::
  ( CacheRM m,
    MonadMetadataStorageQueryAPI m
  ) =>
  GetEventInvocations ->
  m EncJSON
runGetEventInvocations GetEventInvocations {..} = do
  case _geiInvocationsBy of
    GIBEventId _ _ -> pure ()
    GIBEvent event -> case event of
      SEOneOff -> pure ()
      SECron name -> checkExists name
  WithTotalCount count invocations <- fetchInvocations _geiInvocationsBy _geiPagination
  pure $
    encJFromJValue $
      J.object
        [ "invocations" J..= invocations,
          "count" J..= count
        ]