{-# LANGUAGE FlexibleContexts      #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE ScopedTypeVariables   #-}

-- This test tests the high-level subscription consumption.

module Network.Nakadi.Subscriptions.Processing.Test where

import           ClassyPrelude

import           Control.Lens
import           Control.Monad.Logger
import           Control.Monad.Trans.Resource
import           Data.Aeson
import           Network.Nakadi
import qualified Network.Nakadi.Lenses         as L
import           Network.Nakadi.Tests.Common
import           Test.Tasty
import           Test.Tasty.HUnit

testSubscriptionsProcessing :: Config App -> TestTree
testSubscriptionsProcessing confTemplate =
  let mkConf commitStrategy nWorkers =
        confTemplate & setCommitStrategy commitStrategy & setWorkerThreads nWorkers
  in  testGroup
        "Processing"
        [ testCase "SubscriptionProcessing/async/TimeBuffer/singleWorker"
          $ testSubscriptionHighLevelProcessing (mkConf (CommitAsync (CommitTimeBuffer 200)) 1)
        , testCase "SubscriptionProcessing/sync/singleWorker"
          $ testSubscriptionHighLevelProcessing (mkConf CommitSync 1)
        , testCase "SubscriptionProcessing/async/NoBuffer/singleWorker"
          $ testSubscriptionHighLevelProcessing (mkConf (CommitAsync CommitNoBuffer) 1)
        , testCase "SubscriptionProcessing/async/SmartBuffer/singleWorker"
          $ testSubscriptionHighLevelProcessing (mkConf (CommitAsync CommitSmartBuffer) 1)
        , testCase "SubscriptionProcessing/async/TimeBuffer/concurrentWorkers"
          $ testSubscriptionHighLevelProcessing (mkConf (CommitAsync (CommitTimeBuffer 200)) 8)
        , testCase "SubscriptionProcessing/sync/concurrentWorkers"
          $ testSubscriptionHighLevelProcessing (mkConf CommitSync 8)
        , testCase "SubscriptionProcessing/async/NoBuffer/concurrentWorkers"
          $ testSubscriptionHighLevelProcessing (mkConf (CommitAsync CommitNoBuffer) 8)
        , testCase "SubscriptionProcessing/async/SmartBuffer/concurrentWorkers"
          $ testSubscriptionHighLevelProcessing (mkConf (CommitAsync CommitSmartBuffer) 8)
        ]

data ConsumptionDone = ConsumptionDone deriving (Show, Typeable)

instance Exception ConsumptionDone

testSubscriptionHighLevelProcessing :: Config App -> Assertion
testSubscriptionHighLevelProcessing conf' = runApp $ do
  logger <- askLoggerIO
  let logFunc src lev str = liftIO $ logger defaultLoc src lev str
      conf = conf' & setBatchFlushTimeout 1 & setMaxUncommittedEvents 5000 & setBatchLimit 10
  runNakadiT (conf & setLogFunc logFunc) $ do
    counter <- newIORef 0
    events  <- mapM genMyDataChangeEventIdx [1 .. nEvents] :: NakadiT App App [DataChangeEvent Foo]
    publishAndConsume events counter `catch` \(_exn :: ConsumptionDone) -> pure ()
    eventsRead <- readIORef counter
    liftIO $ nEvents @=? eventsRead
 where
  before :: (MonadUnliftIO m, MonadNakadi App m) => m SubscriptionId
  before = do
    recreateEvent myEventType
    subscription <- subscriptionCreate SubscriptionRequest
      { _owningApplication    = "test-suite"
      , _eventTypes           = [myEventTypeName]
      , _consumerGroup        = Nothing -- ??
      , _subscriptionPosition = Just SubscriptionPositionEnd
      }
    pure $ subscription ^. L.id

  after :: (MonadUnliftIO m, MonadNakadi App m) => SubscriptionId -> m ()
  after subscriptionId = do
    subscriptionDelete subscriptionId
    eventTypeDelete myEventTypeName `catch` ignoreExnNotFound ()

  nEvents :: Int
  nEvents = 10000

  publishAndConsume
    :: (ToJSON a, FromJSON a, Show a) => [DataChangeEvent a] -> IORef Int -> NakadiT App App ()
  publishAndConsume events counter = bracket before after $ \subscriptionId -> do
    let n = length events
    publisherHandle <- async $ delayedPublish Nothing events
    liftIO $ linkAsync publisherHandle
    forever . runResourceT $ do
      subscriptionProcess subscriptionId
        $ \(batch :: SubscriptionEventStreamBatch (DataChangeEvent Foo)) -> do
            let eventsReceived = fromMaybe mempty (batch ^. L.events)
            modifyIORef counter (+ length eventsReceived)
            eventsRead <- readIORef counter
            when (n <= eventsRead) $ throwIO ConsumptionDone
      putStrLn "Subscription Processing terminated, will restart."