Postable.hs

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