module Freckle.App.Test.Hspec.Runner
  ( run
  , runParConfig
  , runWith
  , makeParallelConfig
  ) where

import Freckle.App.Prelude

import Control.Concurrent (getNumCapabilities, setNumCapabilities)
import Control.Monad.Trans.Maybe (MaybeT(MaybeT), runMaybeT)
import Data.List (isInfixOf)
import qualified Prelude as Unsafe (read)
import System.Environment (getArgs, lookupEnv)
import Test.Hspec (Spec)
import Test.Hspec.JUnit
  (configWithJUnit, defaultJUnitConfig, setJUnitConfigOutputFile)
import Test.Hspec.Runner
  ( Config
  , Path
  , Summary
  , configConcurrentJobs
  , configSkipPredicate
  , defaultConfig
  , evaluateSummary
  , readConfig
  , runSpec
  )

run :: String -> Spec -> IO ()
run = runWith defaultConfig

runParConfig :: String -> Spec -> IO ()
runParConfig name spec = do
  config <- makeParallelConfig defaultConfig
  runWith config name spec

runWith :: Config -> String -> Spec -> IO ()
runWith config name spec = do
  args <- getArgs
  isCircle <- isJust <$> lookupEnv "CIRCLECI"
  let runner = if isCircle then junit else hspec

  -- Run unreliable tests first, so local dev errors are reported for reliable
  -- specs at the end
  putStrLn "Running UNRELIABLE tests; failures here should not fail the build"
  void $ runner ("unreliable-" <> name) id =<< load
    args
    (skip reliableTests config)

  putStrLn "Running RELIABLE"
  reliableSummary <- runner name id
    =<< load args (skip (anys [unreliableTests, isolatedTests]) config)

  putStrLn "Running ISOLATED"
  isolatedSummary <- runner ("isolated-" <> name) noConcurrency
    =<< load args (skip (not . isolatedTests) config)

  evaluateSummary $ reliableSummary <> isolatedSummary
 where
  load = flip readConfig
  junit filename changeConfig =
    (spec `runJUnitSpec` ("/tmp/junit", filename)) . changeConfig
  hspec _ changeConfig = runSpec spec . changeConfig
  noConcurrency x = x { configConcurrentJobs = Just 1 }

runJUnitSpec :: Spec -> (FilePath, String) -> Config -> IO Summary
runJUnitSpec spec (path, name) config =
  spec `runSpec` configWithJUnit junitConfig config
 where
  filePath = path <> "/" <> name <> "/test_results.xml"
  junitConfig =
    setJUnitConfigOutputFile filePath $ defaultJUnitConfig $ pack name

makeParallelConfig :: Config -> IO Config
makeParallelConfig config = do
  jobCores <- fromMaybe 1 <$> runMaybeT
    (MaybeT lookupTestCapabilities <|> MaybeT lookupHostCapabilities)
  putStrLn $ "Running spec with " <> show jobCores <> " cores"
  setNumCapabilities jobCores
  -- Api specs are IO bound, having more jobs than cores allows for more
  -- cooperative IO from green thread interleaving.
  pure config { configConcurrentJobs = Just $ jobCores * 4 }

lookupTestCapabilities :: IO (Maybe Int)
lookupTestCapabilities = fmap Unsafe.read <$> lookupEnv "TEST_CAPABILITIES"

lookupHostCapabilities :: IO (Maybe Int)
lookupHostCapabilities = Just . reduceCapabilities <$> getNumCapabilities

-- Reduce capabilities to avoid contention with postgres
reduceCapabilities :: Int -> Int
reduceCapabilities = max 1 . (`div` 2)

skip :: (Path -> Bool) -> Config -> Config
skip predicate config = config { configSkipPredicate = Just predicate }

unreliableTests :: Path -> Bool
unreliableTests = ("UNRELIABLE" `isInfixOf`) . snd

reliableTests :: Path -> Bool
reliableTests = not . unreliableTests

isolatedTests :: Path -> Bool
isolatedTests = ("ISOLATED" `isInfixOf`) . snd

anys :: [a -> Bool] -> a -> Bool
anys xs a = or $ fmap (\f -> f a) xs