module BackoffProp (spec) where

import Data.Maybe (listToMaybe)
import Data.Time (NominalDiffTime)
import qualified Hedgehog.Gen as Gen
import qualified Hedgehog.Range as Range
import HomeAssistant.Runtime.Supervisor (Backoff (..), backoffDelay)
import Test.Hspec (Spec, describe, it)
import Test.Hspec.Hedgehog (hedgehog, forAll, (===))

spec :: Spec
spec = describe "backoffDelay" $
  it "doubles from base, clamped at cap" $ hedgehog $ do
    baseD <- forAll $ Gen.double (Range.constant 0.0001 10)
    ratio <- forAll $ Gen.double (Range.constant 1 100)
    let base = realToFrac baseD :: NominalDiffTime
        cap = realToFrac (baseD * ratio) :: NominalDiffTime
        backoff = Backoff base cap 1
        delays = map (backoffDelay backoff) [1 .. 100 :: Int]
    listToMaybe delays === Just (min cap base)
    mapM_ (\(a, b) -> b === min cap (a * 2)) (zip delays (drop 1 delays))