module Network.Telegram.API.Bot.Capacity.Postable (Postable (..), Initial) where

import "aeson" Data.Aeson (FromJSON, Value, decode)
import "base" Control.Exception (try)
import "base" Control.Monad (join)
import "base" Data.Maybe (fromJust)
import "http-client" Network.HTTP.Client (Response (responseBody))
import "text" Data.Text (unpack)
import "transformers" Control.Monad.Trans.Class (lift)
import "transformers" Control.Monad.Trans.Except (ExceptT (ExceptT))
import "transformers" Control.Monad.Trans.Reader (ask)

import qualified "wreq" Network.Wreq.Session as Wreq (post)

import Network.Telegram.API.Bot.Core (Telegram, Token (Token), Ok, result)

type family Initial a = r | r -> a

class FromJSON a => Postable a where
        {-# MINIMAL initial_value, post_endpoint #-}
        initial_value :: Initial a -> Value
        post_endpoint :: Initial a -> String

        post :: Initial a -> Telegram e a
        post x = snd <$> ask >>= \(session, Token token) -> lift . ExceptT . try
                . fmap (fromJust . join . fmap result . decode @(Ok a) . responseBody)
                        . flip (Wreq.post session) (initial_value x) $
                                "https://api.telegram.org/" <> unpack token <> "/" <> post_endpoint x