{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TypeApplications #-}

module Minilang.ServerSpec where

import Data.Aeson (eitherDecode, FromJSON)
import Minilang.API (Score)
import Minilang.Server (serveAPI)
import Network.Wai (Application)
import Test.Hspec (Spec, it)
import Test.Hspec.Wai (get, matchBody, shouldRespondWith, with)
import Test.Hspec.Wai.Matcher (MatchBody (..))
import Data.Data (Proxy (..))

spec :: Spec
spec = with app $
  it "GET /api/leaderboard returns empty list of scores" $ do
    get "/api/leaderboard"
      `shouldRespondWith` 200 {matchBody = arrayOfLengthOf (Proxy @Score) 2}

arrayOfLengthOf :: forall elem proxy . (FromJSON elem) => proxy elem -> Int -> MatchBody
arrayOfLengthOf _ len = MatchBody $ \_ actual ->
  case eitherDecode actual of
    Right (scores :: [elem]) ->
      if length scores == len
        then Nothing
        else Just $ "Expected array of length " ++ show len ++ ", but got " ++ show (length scores)
    Left err -> Just $ "Failed to decode JSON: " ++ err

app :: IO Application
app = pure serveAPI