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

import Prelude

import Control.Applicative ((<|>))
import Control.Concurrent (getNumCapabilities, setNumCapabilities)
import Control.Monad (void)
import Control.Monad.Trans.Maybe (MaybeT(MaybeT), runMaybeT)
import Data.List (isInfixOf)
import Data.Maybe (fromMaybe, isJust)
import System.Environment (getArgs, lookupEnv)
import Test.HSpec.JUnit (runJUnitSpec)
import Test.Hspec (Spec)
import Test.Hspec.Runner
  ( Config
  , Path
  , 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 }

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 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