{-# LANGUAGE ScopedTypeVariables #-}

-- |
--  Send anonymized metrics to the telemetry server regarding usage of various
--  features of Hasura.
--
-- The general workflow for telemetry is as follows:
--
-- 1. We generate metrics for each backend in the graphql-engine code and send it to 'telemetryUrl'.
--    The relevant types can be found in "Hasura.Server.Telemetry.Types".
-- 2. The 'telemetryUrl' endpoint is handled by code in:
--    <https://github.com/hasura/hasura-analytics/tree/hge-upgrade>, specifically
--    <manager/main.go> and <manager/analytics.go>.
--    This server endpoint receives the telemetry payload and sends it to another graphql-engine
--    which runs locally and is backed by a postgres database.
--    The database schema for the telemetry endpoint can also be found in the same repo under <hge/migrations/>.
-- 3. The information from the postgres db can be viewed in Metabase:
--    <https://metabase.telemetry.hasura.io/browse/2/schema/public>.
--
-- For more information about telemetry in general, visit the user-facing docs on the topic:
-- <https://hasura.io/docs/latest/graphql/core/guides/telemetry>.
module Hasura.Server.Telemetry
  ( runTelemetry,
    mkTelemetryLog,
  )
where

import CI qualified
import Control.Concurrent.Extended qualified as C
import Control.Exception (try)
import Control.Lens
import Data.Aeson qualified as A
import Data.ByteString.Lazy qualified as BL
import Data.HashMap.Strict qualified as HM
import Data.HashMap.Strict qualified as Map
import Data.List qualified as L
import Data.List.Extended qualified as L
import Data.Text qualified as T
import Data.Text.Conversions (UTF8 (..), decodeText)
import Hasura.HTTP
import Hasura.Logging
import Hasura.Prelude
import Hasura.RQL.Types.Action
import Hasura.RQL.Types.Common
import Hasura.RQL.Types.CustomTypes
import Hasura.RQL.Types.Metadata.Instances ()
import Hasura.RQL.Types.SchemaCache
import Hasura.RQL.Types.Source
import Hasura.RQL.Types.Table
import Hasura.SQL.AnyBackend qualified as Any
import Hasura.SQL.Backend (BackendType)
import Hasura.SQL.Tag
import Hasura.Server.Telemetry.Counters (dumpServiceTimingMetrics)
import Hasura.Server.Telemetry.Types
import Hasura.Server.Types
import Hasura.Server.Version
import Hasura.Session
import Network.HTTP.Client qualified as HTTP
import Network.HTTP.Types qualified as HTTP
import Network.Wreq qualified as Wreq

-- * Logging and error handling

-- | Logging related
data TelemetryLog = TelemetryLog
  { _tlLogLevel :: !LogLevel,
    _tlType :: !Text,
    _tlMessage :: !Text,
    _tlHttpError :: !(Maybe TelemetryHttpError)
  }
  deriving (Show)

data TelemetryHttpError = TelemetryHttpError
  { tlheStatus :: !(Maybe HTTP.Status),
    tlheUrl :: !Text,
    tlheHttpException :: !(Maybe HttpException),
    tlheResponse :: !(Maybe Text)
  }
  deriving (Show)

instance A.ToJSON TelemetryLog where
  toJSON tl =
    A.object
      [ "type" A..= _tlType tl,
        "message" A..= _tlMessage tl,
        "http_error" A..= (A.toJSON <$> _tlHttpError tl)
      ]

instance A.ToJSON TelemetryHttpError where
  toJSON tlhe =
    A.object
      [ "status_code" A..= (HTTP.statusCode <$> tlheStatus tlhe),
        "url" A..= tlheUrl tlhe,
        "response" A..= tlheResponse tlhe,
        "http_exception" A..= (A.toJSON <$> tlheHttpException tlhe)
      ]

instance ToEngineLog TelemetryLog Hasura where
  toEngineLog tl = (_tlLogLevel tl, ELTInternal ILTTelemetry, A.toJSON tl)

mkHttpError ::
  Text ->
  Maybe (Wreq.Response BL.ByteString) ->
  Maybe HttpException ->
  TelemetryHttpError
mkHttpError url mResp httpEx =
  case mResp of
    Nothing -> TelemetryHttpError Nothing url httpEx Nothing
    Just resp ->
      let status = resp ^. Wreq.responseStatus
          body = decodeText $ UTF8 (resp ^. Wreq.responseBody)
       in TelemetryHttpError (Just status) url httpEx body

mkTelemetryLog :: Text -> Text -> Maybe TelemetryHttpError -> TelemetryLog
mkTelemetryLog = TelemetryLog LevelInfo

-- * Endpoint

telemetryUrl :: Text
telemetryUrl = "https://telemetry.hasura.io/v1/http"

-- * Execution

-- | An infinite loop that sends updated telemetry data ('Metrics') every 24
-- hours. The send time depends on when the server was started and will
-- naturally drift.
runTelemetry ::
  Logger Hasura ->
  HTTP.Manager ->
  -- | an action that always returns the latest schema cache
  IO SchemaCache ->
  MetadataDbId ->
  InstanceId ->
  PGVersion ->
  IO void
runTelemetry (Logger logger) manager getSchemaCache metadataDbUid instanceId pgVersion = do
  let options = wreqOptions manager []
  forever $ do
    schemaCache <- getSchemaCache
    serviceTimings <- dumpServiceTimingMetrics
    ci <- CI.getCI

    -- Creates a telemetry payload for a specific backend.
    let telemetryForSource :: forall (b :: BackendType). HasTag b => SourceInfo b -> TelemetryPayload
        telemetryForSource =
          mkTelemetryPayload
            metadataDbUid
            instanceId
            currentVersion
            pgVersion
            ci
            serviceTimings
            (scRemoteSchemas schemaCache)
            (scActions schemaCache)
        telemetries =
          map
            (\sourceinfo -> (Any.dispatchAnyBackend @HasTag) sourceinfo telemetryForSource)
            (HM.elems (scSources schemaCache))
        payloads = A.encode <$> telemetries

    for_ payloads $ \payload -> do
      logger $ debugLBS $ "metrics_info: " <> payload
      resp <- try $ Wreq.postWith options (T.unpack telemetryUrl) payload
      either logHttpEx handleHttpResp resp
    C.sleep $ days 1
  where
    logHttpEx :: HTTP.HttpException -> IO ()
    logHttpEx ex = do
      let httpErr = Just $ mkHttpError telemetryUrl Nothing (Just $ HttpException ex)
      logger $ mkTelemetryLog "http_exception" "http exception occurred" httpErr

    handleHttpResp resp = do
      let statusCode = resp ^. Wreq.responseStatus . Wreq.statusCode
      logger $ debugLBS $ "http_success: " <> resp ^. Wreq.responseBody
      when (statusCode /= 200) $ do
        let httpErr = Just $ mkHttpError telemetryUrl (Just resp) Nothing
        logger $ mkTelemetryLog "http_error" "failed to post telemetry" httpErr

-- * Generate metrics

-- | Generate a telemetry payload for a specific source by computing their
--   relevant metrics.
--   Additional information that may not be relevant to a particular source
--   such as service timing, remote schemas and actions, will be reported
--   only with the default source.
mkTelemetryPayload ::
  forall (b :: BackendType).
  HasTag b =>
  MetadataDbId ->
  InstanceId ->
  Version ->
  PGVersion ->
  Maybe CI.CI ->
  ServiceTimingMetrics ->
  RemoteSchemaMap ->
  ActionCache ->
  SourceInfo b ->
  TelemetryPayload
mkTelemetryPayload metadataDbId instanceId version pgVersion ci serviceTimings remoteSchemaMap actionCache sourceInfo =
  let topic = versionToTopic version
      sourceMetadata =
        SourceMetadata
          { _smDbUid = forDefaultSource (mdDbIdToDbUid metadataDbId),
            _smDbKind = reify $ backendTag @b,
            _smDbVersion = forDefaultSource (pgToDbVersion pgVersion)
          }
      -- We use this function to attach additional information that is not associated
      -- with a particular source, such as service timing, remote schemas and actions.
      -- These will be reported only with the default source.
      forDefaultSource :: forall a. a -> Maybe a
      forDefaultSource =
        if _siName sourceInfo == SNDefault
          then Just
          else const Nothing
      metrics =
        computeMetrics
          sourceInfo
          (forDefaultSource serviceTimings)
          (forDefaultSource remoteSchemaMap)
          (forDefaultSource actionCache)
      telemetry =
        HasuraTelemetry metadataDbId instanceId version ci sourceMetadata metrics
   in TelemetryPayload topic telemetry

-- | Compute the relevant metrics for a specific source.
computeMetrics ::
  forall (b :: BackendType).
  SourceInfo b ->
  Maybe ServiceTimingMetrics ->
  Maybe RemoteSchemaMap ->
  Maybe ActionCache ->
  Metrics
computeMetrics sourceInfo _mtServiceTimings remoteSchemaMap actionCache =
  let _mtTables = countUserTables (isNothing . _tciViewInfo . _tiCoreInfo)
      _mtViews = countUserTables (isJust . _tciViewInfo . _tiCoreInfo)
      _mtEnumTables = countUserTables (isJust . _tciEnumValues . _tiCoreInfo)
      allRels = join $ Map.elems $ Map.map (getRels . _tciFieldInfoMap . _tiCoreInfo) userTables
      (manualRels, autoRels) = L.partition riIsManual allRels
      _mtRelationships = RelationshipMetric (length manualRels) (length autoRels)
      rolePerms = join $ Map.elems $ Map.map permsOfTbl userTables
      _pmRoles = length $ L.uniques $ fst <$> rolePerms
      allPerms = snd <$> rolePerms
      _pmInsert = calcPerms _permIns allPerms
      _pmSelect = calcPerms _permSel allPerms
      _pmUpdate = calcPerms _permUpd allPerms
      _pmDelete = calcPerms _permDel allPerms
      _mtPermissions =
        PermissionMetric {..}
      _mtEventTriggers =
        Map.size $
          Map.filter (not . Map.null) $
            Map.map _tiEventTriggerInfoMap userTables
      _mtRemoteSchemas = Map.size <$> remoteSchemaMap
      _mtFunctions = Map.size $ Map.filter (not . isSystemDefined . _fiSystemDefined) sourceFunctionCache
      _mtActions = computeActionsMetrics <$> actionCache
   in Metrics {..}
  where
    sourceTableCache = _siTables sourceInfo
    sourceFunctionCache = _siFunctions sourceInfo
    userTables = Map.filter (not . isSystemDefined . _tciSystemDefined . _tiCoreInfo) sourceTableCache
    countUserTables predicate = length . filter predicate $ Map.elems userTables

    calcPerms :: (RolePermInfo b -> Maybe a) -> [RolePermInfo b] -> Int
    calcPerms fn perms = length $ mapMaybe fn perms

    permsOfTbl :: TableInfo b -> [(RoleName, RolePermInfo b)]
    permsOfTbl = Map.toList . _tiRolePermInfoMap

-- | Compute the relevant metrics for actions from the action cache.
computeActionsMetrics :: ActionCache -> ActionMetric
computeActionsMetrics actionCache =
  ActionMetric syncActionsLen asyncActionsLen queryActionsLen typeRelationships customTypesLen
  where
    actions = Map.elems actionCache
    syncActionsLen = length . filter ((== ActionMutation ActionSynchronous) . _adType . _aiDefinition) $ actions
    asyncActionsLen = length . filter ((== ActionMutation ActionAsynchronous) . _adType . _aiDefinition) $ actions
    queryActionsLen = length . filter ((== ActionQuery) . _adType . _aiDefinition) $ actions

    outputTypesLen = length . L.nub . map (_adOutputType . _aiDefinition) $ actions
    inputTypesLen = length . L.nub . concatMap (map _argType . _adArguments . _aiDefinition) $ actions
    customTypesLen = inputTypesLen + outputTypesLen

    typeRelationships =
      length . L.nub
        . concatMap
          ( \aInfo -> map _trName $ case (snd . _aiOutputType $ aInfo) of
              AOTObject aot -> _otdRelationships . _aotDefinition $ aot
              AOTScalar _ -> []
          )
        $ actions

-- | Decide which topic (telemetry table) we should use based on the version.
versionToTopic :: Version -> Topic
versionToTopic = \case
  VersionDev _ -> Topic "server_metrics_v2_test"
  VersionRelease _ -> Topic "server_metrics_v2"