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

module Minilang.ServerSpec where

import Control.Concurrent.STM (newTVarIO)
import Control.Monad (void)
import Data.Aeson (FromJSON, eitherDecode, encode)
import Data.ByteString (isInfixOf, toStrict)
import qualified Data.ByteString as BS
import qualified Data.ByteString.Base64.Lazy as Base64
import Data.ByteString.Lazy (ByteString)
import Data.Data (Proxy (..))
import Minilang.API (Score, User (..), newToken)
import Minilang.App (Env (..), makeEnv)
import Minilang.Server (serveAPI)
import Network.Wai (Application)
import Network.Wai.Test (SResponse)
import System.Random (StdGen, mkStdGen64)
import Test.Hspec (Spec, it)
import Test.Hspec.Wai (WaiSession, get, matchBody, post, request, shouldRespondWith, with)
import Test.Hspec.Wai.Matcher (MatchBody (..))

spec :: Spec
spec = with (app testSeed) $ do
  it "GET / returns 'index.html'" $ do
    get "/"
      `shouldRespondWith` 200
        { matchBody = MatchBody $ \_ actual ->
            if "<html>" `isInfixOf` toStrict actual
              then Nothing
              else Just "Expected HTML content"
        }

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

  it "POST /api/register returns registration token given user is not registered" $ do
    let token = "{\"token\":\"" <> Base64.encode (fst $ newToken testSeed) <> "\"}"
    let user = encode $ User "alice"
    postJSON "/api/register" user
      `shouldRespondWith` 201
        { matchBody = MatchBody $ \_ t ->
            if t == token
              then
                Nothing
              else Just ("Expected token " ++ show token ++ ", but got " ++ show t)
        }

  it "POST /api/register returns 400 given user is already registered" $ do
    let user = encode $ User "alice"
    void $ postJSON "/api/register" user
    postJSON "/api/register" user
      `shouldRespondWith` 400

postJSON :: BS.ByteString -> ByteString -> WaiSession () SResponse
postJSON url = request "POST" url [("Content-Type", "application/json")]

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 :: StdGen -> IO Application
app g = do
  env <- makeEnv g
  pure $ serveAPI env

testSeed :: StdGen
testSeed = mkStdGen64 42