module Util.Ajax
  ( postJson
  , delete
  ) where

import           Control.Arrow      (left)
import           Data.Aeson         (FromJSON, ToJSON)
import qualified Data.Aeson         as Aeson
import           Data.Default       (def)
import qualified Data.Map.Lazy      as LM
import           Data.Text          (Text)
import qualified Data.Text          as T
import qualified Data.Text.Encoding as T
import           Reflex.Dom         (Dynamic, Event, IsXhrPayload, MonadWidget,
                                     XhrRequest, XhrRequestConfig (..),
                                     XhrResponse, XhrResponseHeaders (..))
import qualified Reflex.Dom         as R

postJson
  :: forall t m a b. (MonadWidget t m, ToJSON a, FromJSON b)
  => Text
  -> Event t a
  -> m (Event t (Either Text b))
postJson url input =
  fmap getJsonResult <$>
    R.performRequestAsync (R.postJson url <$> input)

delete
  :: forall t m a. (MonadWidget t m)
  => Dynamic t Text
  -> Event t ()
  -> m (Event t (Either Text Text))
delete url fire = do
  response <- R.performRequestAsync (R.attachWith (\u _ -> request "DELETE" u ()) (R.current url) fire)
  return $ fmap getResult response

getJsonResult :: forall a. (FromJSON a) => XhrResponse -> Either Text a
getJsonResult response =
  case getResult response of
    Left l  -> Left l
    Right r -> left T.pack . Aeson.eitherDecodeStrict $ (T.encodeUtf8 r)

getResult :: XhrResponse -> Either Text Text
getResult response =
  case R._xhrResponse_responseText response of
    Just responseText ->
      if R._xhrResponse_status response == 200
        then Right responseText
        else Left responseText
    _ -> Left "NoKey"

request :: forall a. (IsXhrPayload a) => Text -> Text -> a -> XhrRequest a
request method url sendData =
  let
    config = XhrRequestConfig
      { _xhrRequestConfig_headers = def
      , _xhrRequestConfig_user = def
      , _xhrRequestConfig_password = def
      , _xhrRequestConfig_responseType = def
      , _xhrRequestConfig_responseHeaders = def
      , _xhrRequestConfig_withCredentials = False
      , _xhrRequestConfig_sendData = sendData
      }
  in
    R.xhrRequest method url config